STAAD.Pro 2006 TECHNICAL REFERENCE MANUAL A Bentley Solutions Center Part Number: DAA036990-1/0001 www.reiworld.com www.bentley.
STAAD.Pro 2006 is a suite of proprietary computer programs of Research Engineers, a Bentley Solutions Center. Although every effort has been made to ensure the correctness of these programs, REI will not accept responsibility for any mistake, error or misrepresentation in or as a result of the usage of these programs. RELEASE 2006 © 2006 Bentley Systems, Incorporated. All Rights Reserved.
About STAAD.Pro STAAD.Pro is a general purpose structural analysis and design program with applications primarily in the building industry - commercial buildings, bridges and highway structures, industrial structures, chemical plant structures, dams, retaining walls, turbine foundations, culverts and other embedded structures, etc. The program hence consists of the following facilities to enable this task. 1. 2. 3. 4. 5. 6.
About the STAAD.Pro Documentation The documentation for STAAD.Pro consists of a set of manuals as described below. These manuals are normally provided only in the electronic format, with perhaps some exceptions such as the Getting Started Manual which may be supplied as a printed book to first time and new-version buyers. All the manuals can be accessed from the Help facilities of STAAD.Pro. Users who wish to obtain a printed copy of the books may contact Research Engineers.
Table of Contents STAAD.PRO Technical Reference Manual Section 1 General Description 1- 1.1 1.2 1.3 1.4 1.5 1-1 2 2 3 4 4 7 11 18 18 31 35 37 39 41 42 42 42 43 47 48 48 49 49 50 50 53 54 55 56 57 57 57 58 60 62 62 1 - 65 Introduction Input Generation Types of Structures Unit Systems Structure Geometry and Coordinate Systems 1.5.1 Global Coordinate System 1.5.2 Local Coordinate System 1.5.3 Relationship Between Global & Local Coordinates 1.6 Finite Element Information 1.6.1 Plate/Shell Element 1.6.
1.17 1.18 1.19 1.20 1.21 1.22 1.23 1.24 1.25 1.26 Section 2 1.16.7 Support Displacement Load 1 - 65 1.16.8 Loading on Elements 65 Load Generator 67 1.17.1 Moving Load Generator 67 1.17.2 Seismic Load Generator based on UBC, IBC and other codes 68 1.17.3 Wind Load Generator 69 Analysis Facilities 70 1.18.1 Stiffness Analysis 70 1.18.2 Second Order Analysis 75 1.18.2.1 P-Delta Analysis 75 1.18.2.2 Imperfection Analysis 77 1.18.2.3 Non Linear Analysis 77 1.18.2.4 Multi-Linear Analysis 77 1.18.2.
Section 3 2.3.7 Torsion per Publication T114 2.3.8 Design of Web Tapered Sections 2.3.9 Slender compression elements 2.4 Design Parameters 2.5 Code Checking 2.6 Member Selection 2.6.1 Member Selection by Optimization 2.6.2 Deflection Check With Steel Design 2.7 Truss Members 2.8 Unsymmetric Sections 2.9 Composite Beam Design as per AISC-ASD 2.10 Plate Girders 2.11 Tabulated Results of Steel Design 2.12 Weld Design 2.13 Steel Design per AASHTO Specifications 2.14 Steel Design per AISC/LRFD Specification 2.
3.8.2 Shear Wall Design 3.8.3 Slabs and RC Designer 3.8.4 Design of I-shaped beams per ACI-318 Section 4 Section 5 3 - 20 28 3 - 35 Timber Design 4- 4.1 4.2 4.3 4.4 4.5 4.6 4-1 13 16 17 18 4 - 18 Timber Design Design Operations Input Specification Code Checking Orientation of Lamination Member Selection Commands and Input Instructions 5- 5.1 Command Language Conventions 5-2 5.1.1 Elements of The Commands 3 5.1.2 Command Formats 5 5.1.3 Listing of Members by Specification of Global Ranges 8 5.
5.21 5.22 5.23 5.24 5.25 5.26 5.27 5.28 5.29 5.30 5.31 5.20.8 Curved Member Specification 5 - 86 5.20.9 Applying Fireproofing on members 98 Element/Surface Property Specification 103 5.21.1 Element Property Specification 104 5.21.2 Surface Property Specification 105 Member/Element Releases 106 5.22.1 Member Release Specification 107 5.22.2 Element Release Specification 110 5.22.3 Element Ignore Stiffness 112 Member Truss/Cable/Tension/Compression Specification 113 5.23.
5.32 5.33 5.34 5.35 5.36 5.37 5.38 5.39 5.40 5.41 5.31.2.10 Canadian (NRC 1995) Seismic Load 5 - 221 5.31.3 Definition of Wind Load 234 5.31.4 Definition of Time History Load 238 5.31.5 Definition of Snow Load 244 Loading Specifications 245 5.32.1 Joint Load Specification 247 5.32.2 Member Load Specification 248 5.32.3 Element Load Specifications 251 5.32.3.1 Element Load Specification - Plates 252 5.32.3.2 Element Load Specification - Solids 256 5.32.3.3 Element Load Specification - Joints 258 5.32.3.
5.42 5.43 5.44 5.45 5.46 5.47 5.48 5.49 5.50 5.51 5.52 5.53 5.54 Index Stress/Force output printing for Surface Entities Print Section Displacement Print Force Envelope Specification Post Analysis Printer Plot Specifications Size Specification Steel and Aluminum Design Specifications 5.47.1 Parameter Specifications 5.47.2 Code Checking Specification 5.47.3 Member Selection Specification 5.47.4 Member Selection by Optimization 5.47.
1-1 General Description Section 1 1.1 Introduction The STAAD.Pro 2006 Graphical User Interface (GUI) is normally used to create all input specifications and all output reports and displays (See the Graphical Environment manual). These structural modeling and analysis input specifications are stored in a text file with extension “.STD”. When the GUI does a File Open to start a session with an existing model, it gets all of its information from the STD file.
General Description 1-2 Section 1 which the facilities are discussed follows the recommended sequence of their usage in the STD input file. 1.2 Input Generation The GUI (or user) communicates with the STAAD analysis engine through the STD input file. That input file is a text file consisting of a series of commands which are executed sequentially. The commands contain either instructions or data pertaining to analysis and/or design.
Section 1 Specification of the correct structure type reduces the number of equations to be solved during the analysis. This results in a faster and more economic solution for the user. The degrees of freedom associated with frame elements of different types of structures is illustrated in Figure 1.1. Structure Types Figure 1.1 1.4 Unit Systems For input, see section 5.3 The user is allowed to input data and request output in almost all commonly used engineering unit systems including MKS, SI and FPS.
General Description 1-4 Section 1 1.5 Structure Geometry and Coordinate Systems A structure is an assembly of individual components such as beams, columns, slabs, plates etc.. In STAAD, frame elements and plate elements may be used to model the structural components. Typically, modeling of the structure geometry consists of two steps: A. Identification and description of joints or nodes. B. Modeling of members or elements through specification of connectivity (incidences) between joints.
Section 1 directions. The translational degrees of freedom are denoted by u 1 , u 2 , u 3 and the rotational degrees of freedom are denoted by u 4 , u5 & u6. B. Cylindrical Coordinate System: In this coordinate system, (Fig. 1.3) the X and Y coordinates of the conventional cartesian system are replaced by R (radius) and Ø (angle in degrees). The Z coordinate is identical to the Z coordinate of the cartesian system and its positive direction is determined by the right hand rule. C.
General Description 1-6 Section 1 Figure 1.3 : Cylindrical Coordinate System Figure 1.
Section 1 1.5.2 Local Coordinate System A local coordinate system is associated with each member. Each axis of the local orthogonal coordinate system is also based on the right hand rule. Fig. 1.5 shows a beam member with start joint 'i' and end joint 'j'. The positive direction of the local x-axis is determined by joining 'i' to 'j' and projecting it in the same direction. The right hand rule may be applied to obtain the positive directions of the local y and z axes.
General Description 1-8 Section 1 Figure 1.5a Figure 1.
Section 1 Figure 1.6a - Local axis system for various cross sections when global Y axis is vertical.
General Description 1-10 Section 1 Figure 1.6b - Local axis system for various cross sections when global Z axis is vertical (SET Z UP is specified).
Section 1 1.5.3 Relationship Between Global & Local Coordinates Since the input for member loads can be provided in the local and global coordinate system and the output for member-end-forces is printed in the local coordinate system, it is important to know the relationship between the local and global coordinate systems. This relationship is defined by an angle measured in the following specified way. This angle will be defined as the beta (β) angle.
General Description 1-12 Section 1 Reference Point An alternative to providing the member orientation is to input the coordinates (or a joint number) which will be a reference point located in the member x-y plane (x-z plane for SET Z UP) but not on the axis of the member. From the location of the reference point, the program automatically calculates the orientation of the member x-y plane (x-z plane for SET Z UP).
Section 1 Figure 1.
General Description 1-14 Section 1 Figure 1.
Section 1 Figure 1.
General Description 1-16 Section 1 Figure 1.
Section 1 Figure 1.
General Description 1-18 Section 1 1.6 Finite Element Information For input, see sections 5.11, 5.13, 5.14, 5.21, 5.24, and 5.32.3 STAAD is equipped with a plate/shell finite element, solid finite element and an entity called the surface element. The features of each is explained below. 1.6.1 Plate/Shell Element The Plate/Shell finite element is based on the hybrid element formulation. The element can be 3-noded (triangular) or 4-noded (quadrilateral).
Section 1 Geometry Modeling Considerations The following geometry related modeling rules should be remembered while using the plate/shell element 1) The program automatically generates a fictitious fifth node "O" (center node - see Fig. 1.8) at the element center. 2) While assigning nodes to an element in the input data, it is essential that the nodes be specified either clockwise or counter clockwise (Fig. 1.9).
General Description 1-20 Section 1 Correct numbering Generated Node (Center Node) Incorrect numbering Figure 1.8 Figure 1.9 Good Elements Bad Elements Figure 1.10 Figure 1.11 Figure 1.13 Theoretical Basis The STAAD plate finite element is based on hybrid finite element formulations. A complete quadratic stress distribution is assumed. For plane stress action, the assumed stress distribution is as follows. σy τyx τxy σx τxy τyx σy Figure 1.
Section 1 Complete quadratic assumed stress distribution: ⎛ σ x ⎞ ⎡1 x y 0 0 0 0 x2 2xy ⎜ ⎟ ⎢ 2 ⎜ σ y ⎟ = ⎢0 0 0 1 x y 0 y 0 ⎜⎜ ⎟⎟ ⎢ 0 y 0 0 0 x 1 2 xy y2 τ − − − − ⎝ xy ⎠ ⎣⎢ 0 ⎤ ⎥ 2xy ⎥ − x 2 ⎥⎥ ⎦ ⎛ a1 ⎞ ⎜ ⎟ ⎜ a2 ⎟ ⎜a ⎟ ⎜ 3⎟ ⎜ M ⎟ ⎜ ⎟ ⎝ a10 ⎠ a 1 through a 10 = constants of stress polynomials. The following quadratic stress distribution is assumed for plate bending action: Q Qy x M xy Z M yx My Qx Mx Mx M xy Y My X M yx Qy Figure 1.
General Description 1-22 Section 1 The distinguishing features of this finite element are: 1) Displacement compatibility between the plane stress component of one element and the plate bending component of an adjacent element which is at an angle to the first (see Fig. below) is achieved by the elements. This compatibility requirement is usually ignored in most flat shell/plate elements. Figure 1.
Section 1 1-23 8) The plate bending portion can handle thick and thin plates, thus extending the usefulness of the plate elements into a multiplicity of problems. In addition, the thickness of the plate is taken into consideration in calculating the out of plane shear. 9) The plane stress triangle behaves almost on par with the well known linear stress triangle. The triangles of most similar flat shell elements incorporate the constant stress triangle which has slow rates of convergence.
General Description 1-24 Section 1 Output of Plate Element Stresses and Moments For the sign convention of output stress and moments, please see Fig. 1.13. ELEMENT stress and moment output is available at the following locations: A. Center point of the element. B. All corner nodes of the element. C. At any user specified point within the element. Following are the items included in the ELEMENT STRESS output.
Section 1 Notes: 1. All element stress output is in the local coordinate system. The direction and sense of the element stresses are explained in Fig. 1.13. 2. To obtain element stresses at a specified point within the element, the user must provide the location (local X, local Y) in the coordinate system for the element. The origin of the local coordinate system coincides with the center of the element. 3.
General Description 1-26 Section 1 Sign Convention of Plate Element Stresses and Moments Figure 1.18 Figure 1.
Section 1 Figure 1.20 Figure 1.
General Description 1-28 Section 1 Figure 1.22 Figure 1.
Section 1 Figure 1.24 Figure 1.
General Description 1-30 Section 1 Please note the following few restrictions in using the finite element portion of STAAD: 1) Members, plate elements, solid elements and surface elements can all be part of a single STAAD model. The MEMBER INCIDENCES input must precede the INCIDENCE input for plates, solids or surfaces. All INCIDENCES must precede other input such as properties, constants, releases, loads, etc.
Section 1 However the user has to decide between adopting a numbering system which reduces the computation time versus a numbering system which increases the ease of defining the structure geometry. 2 1 5 3 6 4 7 8 Efficient Element numbering 5 3 1 2 4 7 6 8 Inefficient Element numbering Figure 1.26 1.6.2 Solid Element Solid elements enable the solution of structural problems involving general three dimensional stresses.
General Description 1-32 Section 1 Theoretical Basis The solid element used in STAAD is of eight noded isoparametric type. These elements have three translational degrees-of-freedom per node. Figure 1.27 By collapsing various nodes together, an eight noded solid element can be degenerated to the following forms with four to seven nodes. Joints 1, 2, and 3 must be retained as a triangle. Figure 1.
Section 1 8 x = ∑ hixi , i =1 8 y = ∑ hiyi , i =1 8 z = ∑ hizi i =1 where x, y and z are the coordinates of any point in the element and x i , y i , z i , i=1,..,8 are the coordinates of nodes defined in the global coordinate system. The interpolation functions, h i are defined in the natural coordinate system, (r,s,t). Each of r, s and t varies between -1 and +1.
General Description 1-34 Section 1 Local Coordinate System The local coordinate system used in solid elements is the same as the global system as shown below : Figure 1.29 Properties and Constants Unlike members and shell (plate) elements, no properties are required for solid elements. However, the constants such as modulus of elasticity and Poisson’s ratio are to be specified. Also, Density needs to be provided if selfweight is included in any load case.
Section 1 Output of Solid Element Stresses Element stresses may be obtained at the center and at the joints of the solid element. The items that are printed are : Normal Stresses : SXX, SYY and SZZ Shear Stresses : SXY, SYZ and SZX Principal stresses : S1, S2 and S3. Von Mises stresses: __________________________ SIGE= .707 √ (S1-S2) 2 + (S2-S3) 2 + (S3-S1) 2 Direction cosines : 6 direction cosines are printed, following the expression DC, corresponding to the first two principal stress directions. 1.6.
General Description 1-36 Section 1 The attributes associated with surfaces, and the sections of this manual where the information may be obtained, are listed below: Attributes Related Sections Surfaces incidences - 5.13.3 Openings in surfaces - 5.13.3 Local coordinate system for surfaces - 1.6.3 Specifying sections for stress/force output - 5.13.3 Property for surfaces - 5.21.2 Material constants - 5.26.3 Surface loading - 5.32.3.4 Stress/Force output printing - 5.
Section 1 The diagram below shows directions and sign convention of local axes and forces. Figure 1.30 1.7 Member Properties The following types of member property specifications are available in STAAD: See section 5.20 A) B) C) D) E) F) PRISMATIC property specifications Standard Steel shapes from built-in section library User created steel tables TAPERED sections Through ASSIGN command CURVED specification Shear Area for members refers to the shear stiffness effective area.
General Description 1-38 Section 1 (12EI/L 3 )/(1+Φ) where Φ = (12 EI) / (GA s L 2 ) and A s is the shear stiffness effective area. PHI (Φ)is usually ignored in basic beam theory. STAAD will include the PHI term unless the SET SHEAR command is entered. Shear stress effective area is a different quantity that is used to calculate shear stress and in code checking. For a rectangular cross section, the shear stress effective area is usually taken as 2/3 rds of the cross sectional area.
Section 1 1.7.1 Prismatic Properties The following prismatic properties are required for analysis: See section 5.20.2 AX IX IY IZ = = = = Cross sectional area Torsional constant Moment of inertia about y-axis. Moment of inertia about z-axis. In addition, the user may choose to specify the following properties: AY AZ YD ZD = = = = Effective shear area for shear force parallel to local y-axis. Effective shear area for shear force parallel to local z-axis. Depth of section parallel to local y-axis.
General Description 1-40 Section 1 STAAD automatically considers the additional deflection of members due to pure shear (in addition to deflection due to ordinary bending theory). To ignore the shear deflection, enter a SET SHEAR command before the joint coordinates. This will bring results close to textbook results. The depths in the two major directions (YD and ZD) are used in the program to calculate the section moduli. These are needed only to calculate member stresses or to perform concrete design.
Section 1 Table 1.1 Required properties Structural Type Required Properties TRUSS structure PLANE structure FLOOR structure SPACE structure AX AX, IZ or IY IX, IZ or IY AX, IX, IY, IZ 1.7.2 Built-In Steel Section Library See section 2.2.1 and 5.20.1 This feature of the program allows the user to specify section names of standard steel shapes manufactured in different countries. Information pertaining to the American steel shapes is available in section 2.
General Description 1-42 Section 1 1.7.3 User Provided Steel Table See sections 5.19, 5.20.4 and Examples Manual problem 17 The user can provide a customized steel table with designated names and proper corresponding properties. The program can then find member properties from those tables. Member selection may also be performed with the program selecting members from the provided tables only.
Section 1 For the keyword COLUMN also, the program will assign an Ishaped beam section (Wide Flange for AISC, UC section for British). If steel design-member selection is requested, a similar type section will be selected. See section 5.20.5 for the command syntax and description of the ASSIGN Command. 1.7.6 Steel Joist and Joist Girders STAAD.Pro now comes with the facilities for specifying steel joists and joist girders.
General Description 1-44 Section 1 The designation for the G series Joist Girders is as shown in page 73 of the Steel Joist Institute publication. STAAD.Pro incorporates the span length also in the name, as shown in the next figure. Figure 1.33 Modeling the joist - Theoretical basis Steel joists are prefabricated, welded steel trusses used at closely spaced intervals to support floor or roof decking.
Section 1 As a result of the above assumption, the following points must be noted with respect to modeling joists: 1) The entire joist is represented in the STAAD input file by a single member. Graphically it will be drawn using a single line. 2) After creating the member, the properties should be assigned from the joist database. 3) The 3D Rendering feature of the program will display those members using a representative Warren type truss.
General Description 1-46 Section 1 Assigning the joists The procedure for assigning the joists is explained in the Graphical User Interface manual. The STAAD joists database includes the weight per length of the joists. So, for selfweight computations in the model, the weight of the joist is automatically considered. An example of a structure with joist (command file input data) is shown below.
Section 1 LOAD COMB 3 1121 PERF ANALY PRINT STAT CHECK PRINT SUPP REAC FINISH 1.7.7 Composite Beams and Composite Decks There are two methods in STAAD for specifying composite beams. Composite beams are members whose property is comprised of an I-shaped steel cross section (like an American W shape) with a concrete slab on top. The steel section and concrete slab act monolithically. The two methods are: a) The EXPLICIT definition method – In this method, the member geometry is first defined as a line.
General Description 1-48 Section 1 b) The composite deck generation method – The laboriousness of the previous procedure can be alleviated to some extent by using the program’s composite deck definition facilities. The program then internally converts the deck into individual composite members (calculating attributes like effective width in the process) during the analysis and design phase.
Section 1 Only one of the attributes described in sections 1.8 and 1.9 can be assigned to a given member. The last one entered will be used. In other words, a MEMBER RELEASE should not be applied on a member which is declared TRUSS, TENSION ONLY or COMPRESSION ONLY. 1.9 Truss/Tension/Compression - Only Members See section 5.23 For analyses which involve members that carry axial loads only, i.e. truss members, there are two methods for specifying this condition.
General Description 1-50 Section 1 1.11 Cable Members STAAD supports 2 types of analysis for cable members - linear and non-linear. 1.11.1 Linearized Cable Members See section 5.23, 5.37 & 1.18.2.5 Cable members may be specified by using the MEMBER CABLE command. While specifying cable members, the initial tension in the cable must be provided. The following paragraph explains how cable stiffness is calculated. The increase in length of a loaded cable is a combination of two effects.
Section 1 1 Kcomb = 1 / Ksag + 1 / Kelastic K comb = (EA/L) / [1+w 2 L 2 EA(cos 2 α)/12T 3 ] Note: When T = infinity, K comb = EA/L When T = 0, K comb = 0 It may be noticed that as the tension increases (sag decreases) the combined stiffness approaches that of the pure elastic situation. The following points need to be considered when using the linear cable member in STAAD : 1) The linear cable member is only a truss member whose properties accommodate the sag factor and initial tension.
General Description 1-52 Section 1 that the user declare the member to be a tension only member by using the MEMBER TENSION command, after the CABLE command. This will ensure that the program will test the nature of the force in the member after the analysis and if it is compressive, the member is switched off and the stiffness matrix re-calculated.
Section 1 1.11.2 Non Linear Cable & Truss Members Cable members for the Non Linear Cable Analysis may be specified by using the MEMBER CABLE command. While specifying cable members, the initial tension in the cable or the unstressed length of the cable may be provided. The user should ensure that all cables will be in sufficient tension for all load cases to converge. Use selfweight in every load case and temperature if appropriate; i.e. don’t enter component cases (e.g. wind only). See section 5.23, 5.
General Description 1-54 Section 1 1.12 Member Offsets See section 5.25 Some members of a structure may not be concurrent with the incident joints thereby creating offsets. This offset distance is specified in terms of global or local coordinate system (i.e. X, Y and Z distances from the incident joint). Secondary forces induced, due to this offset connection, are taken into account in analyzing the structure and also to calculate the individual member forces.
Section 1 1.13 Material Constants See section 5.26 The material constants are: modulus of elasticity (E); weight density (DEN); Poisson's ratio (POISS); co-efficient of thermal expansion (ALPHA), Composite Damping Ratio, and beta angle (BETA) or coordinates for any reference (REF) point. E value for members must be provided or the analysis will not be performed. Weight density (DEN) is used only when selfweight of the structure is to be taken into account.
General Description 1-56 Section 1 1.14 Supports See section 5.27 STAAD allows specifications of supports that are parallel as well as inclined to the global axes. Supports are specified as PINNED, FIXED, or FIXED with different releases (known as FIXED BUT). A pinned support has restraints against all translational movement and none against rotational movement. In other words, a pinned support will have reactions for all forces but will resist no moments.
Section 1 1.15 Master/Slave Joints See section 5.28 The master/slave option is provided to enable the user to model rigid links in the structural system. This facility can be used to model special structural elements like a rigid floor diaphragm. Several slave joints may be provided which will be assigned same displacements as the master joint. The user is also allowed the flexibility to choose the specific degrees of freedom for which the displacement constraints will be imposed on the slaved joints.
General Description 1-58 Section 1 1.16.2 Member Load See section 5.32.2 Three types of member loads may be applied directly to a member of a structure. These loads are uniformly distributed loads, concentrated loads, and linearly varying loads (including trapezoidal). Uniform loads act on the full or partial length of a member. Concentrated loads act at any intermediate, specified point. Linearly varying loads act over the full length of a member.
Section 1 Member Load Configurations - Figure 1.
General Description 1-60 Section 1 1.16.3 Area Load / Oneway Load / Floor Load See section 5.32.4 Often a floor is subjected to a uniform pressure. It could require a lot of work to calculate the equivalent member load for individual members in that floor. However, with the AREA, ONEWAY or FLOOR LOAD facilities, the user can specify the pressure (load per unit square area). The program will calculate the tributary area for these members and calculate the appropriate member loads.
Section 1 Figure 1.37 shows a floor structure with area load specification of 0.1. 6m 4m 6 7 1 2 10 4m 5m 8 3 11 5m X 9 4 12 5 13 6m Z Figure 1.37 Member 1 will have a linear load of 0.3 at one end and 0.2 at the other end. Members 2 and 4 will have a uniform load of 0.5 over the full length. Member 3 will have a linear load of 0.45 and 0.55 at respective ends. Member 5 will have a uniform load of 0.25.
General Description 1-62 Section 1 1.16.4 Fixed End Member Load See section 5.32.7 Load effects on a member may also be specified in terms of its fixed end loads. These loads are given in terms of the member coordinate system and the directions are opposite to the actual load on the member. Each end of a member can have six forces: axial; shear y; shear z; torsion; moment y, and moment z. 1.16.5 Prestress and Poststress Member Load See section 5.32.
Section 1 em = eccentricity of cable at middle of member (in local y-axis) ee = eccentricity of cable at end of member (in local y-axis) L = Length of member 2) The angle of inclination of the cable with respect to the local x-axis (a straight line joining the start and end joints of the member) at the start and end points is small which gives rise to the assumption that sin θ = θ = dy / dx Hence, if the axial force in the cable is P, the vertical component of the force at the ends is P(dy / dx) and the h
General Description 1-64 Section 1 5) The term MEMBER PRESTRESS as used in STAAD signifies the following condition. The structure is constructed first. Then, the prestressing force is applied on the relevant members. As a result, the members deform and depending on their end conditions, forces are transmitted to other members in the structure. In other words, "PRE" refers to the time of placement of the member in the structure relative to the time of stressing.
Section 1 1.16.6 Temperature/Strain Load See section 5.32.6 Uniform temperature difference throughout members and elements may be specified. Temperature differences across both faces of members and through the thickness of plates may also be specified (uniform temperature only for solids).. The program calculates the axial strain (elongation and shrinkage) due to the temperature difference for members. From this it calculates the induced forces in the member and the analysis is done accordingly.
General Description 1-66 Section 1 of the element must be provided in order to facilitate computation of these effects. 4) The self-weight of the elements can be applied using the SELFWEIGHT loading condition. The density of the elements has to be provided in order to facilitate computation of the selfweight. On Solid elements , the loading types available are 1. The self-weight of the solid elements can be applied using the SELFWEIGHT loading condition.
Section 1 1.17 Load Generator – Moving load, Wind & Seismic Load generation is the process of taking a load causing unit such as wind pressure, ground movement or a truck on a bridge, and converting it to a form such as member load or a joint load which can be then be used in the analysis. For seismic loads, a static analysis method or a dynamic analysis method can be adopted. The static analysis method, which is the one referred to here, is based on codes such as UBC, IBC, AIJ, IS1893 etc.
General Description 1-68 Section 1 1.17.2 Seismic Load Generator based on UBC, IBC and other codes See sections 5.31.2 and 5.32.12 The STAAD seismic load generator follows the procedure of equivalent lateral load analysis explained in UBC, IBC and several other codes. It is assumed that the lateral loads will be exerted in X and Z (or X and Y if Z is up) directions (horizontal) and Y (or Z if Z is up) will be the direction of the gravity loads.
Section 1 1.17.3 Wind Load Generator See sections 5.31.5 and 5.32.12 The Wind Load Generator is a utility which takes as input wind pressure and height ranges over which these pressures act and generates nodal point and member loads. This facility is available for two types of structures.
General Description 1-70 Section 1 and hence, they will all receive the load. The concept of members on the windward side shielding the members in the inside regions of the structure does not exist for open structures. As a large structure may consist of hundreds of panels and members, a considerable amount of work in calculating the loads can be avoided by the user with the help of this facility. 1.18 Analysis Facilities The following PERFORM ANALYSIS facilities are available in STAAD.
Section 1 Structural systems such as slabs, plates, spread footings, etc., which transmit loads in 2 directions have to be discretized into a number of 3 or 4 noded finite elements connected to each other at their nodes. Loads may be applied in the form of distributed loads on the element surfaces or as concentrated loads at the joints. The plane stress effects as well as the plate bending effects are taken into consideration in the analysis.
General Description 1-72 Section 1 5) Two types of coordinate systems are used in the generation of the required matrices and are referred to as local and global systems. Local coordinate axes are assigned to each individual element and are oriented such that computing effort for element stiffness matrices are generalized and minimized. Global coordinate axes are a common datum established for all idealized elements so that element forces and displacements may be related to a common frame of reference.
Section 1 1-73 Consideration of Bandwidth The method of decomposition is particularly efficient when applied to a symmetrically banded matrix. For this type of matrix fewer calculations are required due to the fact that elements outside the band are all equal to zero. STAAD takes full advantage of this bandwidth during solution, as it is important to have the least bandwidth to obtain the most efficient solution.
General Description 1-74 Section 1 Modeling and Numerical Instability Problems Instability problems can occur due to two primary reasons. 1) Modeling problem There are a variety of modeling problems which can give rise to instability conditions. They can be classified into two groups. a) Local instability - A local instability is a condition where the fixity conditions at the end(s) of a member are such as to cause an instability in the member about one or more degrees of freedom.
Section 1 1-75 very "flexible" member, viz., when k1>>k2, or k1+k2 ≅ k1, A=1 and hence, 1/(1-A) =1/0. Thus, huge variations in stiffnesses of adjacent members are not permitted. Artificially high E or I values should be reduced when this occurs. Math precision errors are also caused when the units of length and force are not defined correctly for member lengths, member properties, constants etc.
General Description 1-76 Section 1 The lateral loading must be present concurrently with the vertical loading for proper consideration of the P-Delta effect. The REPEAT LOAD facility (see Section 5.32.11) has been created with this requirement in mind. This facility allows the user to combine previously defined primary load cases to create a new primary load case. 3) A new stiffness analysis is carried out based on the revised load vector to generate new deflections.
Section 1 1.18.2.2 Imperfection Analysis See section 5.37 and section 5.26.6 Structures subjected to vertical and lateral loads often experience secondary forces due to curvature imperfections in the columns and beams. This secondary effect is similar to the P-Delta effect. In STAAD the procedure consists of the following steps: 1. First, the deflections and the axial forces in the selected imperfect members are calculated based on the provided external loading. 2.
General Description 1-78 Section 1 any PDELTA, NONLINEAR, dynamic, or TENSION/ COMPRESSION member cases. The multi-linear spring command will initiate an iterative analysis which continues to convergence. 1.18.2.5 Tension / Compression Only Analysis When some members or support springs are linear but carry only tension (or only compression), then this analysis may be used. This analysis is automatically selected if any member or spring has been given the tension or compression only characteristic.
Section 1 The user has control of the number of steps, the maximum number of iterations per step, the convergence tolerance, the artificial stabilizing stiffness, and the minimum amount of stiffness remaining after a cable sags. This method assumes small displacement theory for all members/trusses/elements other than cables & preloaded trusses. The cables and preloaded trusses can have large displacement and moderate/large strain.
General Description 1-80 Section 1 The analysis sequence is as follows: 1. Compute the unstressed length of the nonlinear members based on joint coordinates, pretension, and temperature. 2. Member/Element/Cable stiffness is formed. Cable stiffness is from EA/L and the sag formula plus a geometric stiffness based on current tension. 3. Assemble and solve the global matrix with the percentage of the total applied load used for this load step. 4.
Section 1 8. Do not apply Prestress load, Fixed end load. 9. Do not use Load Combination command to combine cable analysis results. Use a primary case with Repeat Load instead. 1.18.3 Dynamic Analysis Currently available dynamic analysis facilities include solution of the free vibration problem (eigenproblem), response spectrum analysis and forced vibration analysis. 1.18.3.1 Solution of the Eigenproblem See sections 5.30, 5.32.10, 5.
General Description 1-82 Section 1 usually mass motion in other directions at some or all joints and these mass directions (“loads” in weight units) must be entered to be correct. Joint moments that are entered will be considered to be 2 weight moment of inertias (force-length units). Please enter selfweight, joint and element loadings in global directions with the same sign as much as possible so that the “masses” do not cancel each other.
Section 1 In addition, the dynamic results will not reflect the location of a mass within a member (i.e. the masses are lumped at the joints). This means that the motion, of a large mass in the middle of a member relative to the ends of the member, is not considered. This may affect the frequencies and mode shapes. If this is important to the solution, split the member into two.
General Description 1-84 Section 1 be created to include either the positive or negative contribution of seismic results. 1.18.3.5 Response Time History Analysis See Sections 5.31.6 and 5.32.10.2 STAAD is equipped with a facility to perform a response history analysis on a structure subjected to time varying forcing function loads at the joints and/or a ground motion at its base. This analysis is performed using the modal superposition method.
Section 1 Time History Analysis for a Structure Subjected to a Harmonic Loading A Harmonic loading is one in which can be described using the following equation F (t) = F0 sin (ω t + φ) In the above equation, F(t) = Value of the forcing function at any instant of time "t" F 0 = Peak value of the forcing function ω = Frequency of the forcing function φ = Phase Angle A plot of the above equation is shown in the figure below. Figure 1.
General Description 1-86 Section 1 are chosen from this time ′0′ to n*tc in steps of "STEP" where n is the number of cycles and tc is the duration of one cycle. STEP is a value that the user may provide or may choose the default value that is built into the program. STAAD will adjust STEP so that a ¼ cycle will be evenly divided into one or more steps. Users may refer to section 5.31.
Section 1 A Harmonic loading is one in which can be described using the following equation F (t) = F0 sin (ω t + φ) In the above equation, F(t) = Value of the forcing function at any instant of time "t" F 0 = Peak value of the forcing function ω = Frequency of the forcing function φ = Phase Angle A plot of the above equation is shown in the figure below. Figure 1.
General Description 1-88 Section 1 Ground motion or a joint force distribution may be specified. Each global direction may be at a different phase angle. Output frequency points are selected automatically for modal frequencies and for a set number of frequencies between modal frequencies. There is an option to change the number of points between frequencies and an option to add frequencies to the list of output frequencies.
Section 1 Figure 1.39a Figure 1.
General Description 1-90 Section 1 Figure 1.39c Figure 1.
Section 1 Y Y Y Z Z ST 1-91 Z Longer leg RA Y Y Y Z Z Z Figure 1.
General Description Section 1 Y Y Y Z Z 1-92 Z Longer leg ST RA Y Y Y Z Z Z Figure 1.
Section 1 1.19.1 Secondary Analysis See sections 5.40, 5.41, 5.42 and 5.43 Solution of the stiffness equations yield displacements and forces at the joints or end points of the member. STAAD is equipped with the following secondary analysis capabilities to obtain results at intermediate points within a member. 1) 2) 3) 4) Member forces at intermediate sections. Member displacements at intermediate sections. Member stresses at specified sections. Force envelopes.
General Description 1-94 Section 1 1.19.4 Member Stresses at Specified Sections See sections 5.40 and 5.41 Member stresses can be printed at specified intermediate sections as well as at the start and end joints.
Section 1 1.20 Multiple Analyses Structural analysis/design may require multiple analyses in the same run. STAAD allows the user to change input such as member properties, support conditions etc. in an input file to facilitate multiple analyses in the same run. Results from different analyses may be combined for design purposes. For structures with bracing, it may be necessary to make certain members inactive for a particular load case and subsequently activate them for another.
General Description 1-96 Section 1 1.21 Steel/Concrete/Timber Design See sections 2, 3 and 4 Extensive design capabilities are available in STAAD for steel, concrete and timber sections. Detailed information on steel, concrete and timber design is presented in Sections 2, 3 and 4 respectively. 1.22 Footing Design See section 5.52 A footing design facility capable of designing individual footings for user specified support(s) is available.
Section 1 1.24 Plotting Facilities Please refer to the STAAD.Pro Graphical Environment Manual for a complete description of the extensive screen and hardcopy graphical facilities available and information on using them. 1.25 Miscellaneous Facilities STAAD offers the following miscellaneous facilities for problem solution. Perform Rotation See section 5.17 This command can be used to rotate the structure shape through any desired angle about any global axis.
General Description 1-98 Section 1 1.26 Post Processing Facilities All output from the STAAD run may be utilized for further processing by the STAAD.Pro GUI. Please refer to the STAAD.Pro Graphical Environment Manual for a complete description of the extensive screen and hardcopy graphical facilities available and for information on how to use them.
2-1 American Steel Design Section 2 2.1 Design Operations STAAD contains a broad set of facilities for designing structural members as individual components of an analyzed structure. The member design facilities provide the user with the ability to carry out a number of different design operations. These facilities may be used selectively in accordance with the requirements of the design problem.
American Steel Design 2-2 Section 2 2.2 Member Properties For specification of member properties of standard American steel sections, the steel section library available in STAAD may be used. The syntax for specifying the names of built-in steel shapes is described in the next section. 2.2.1 Built - in Steel Section Library The following sections describe specification of steel sections from the AISC (9th Edition, 1989) Steel Tables.
Section 2 10 TO 20 BY 2 TA ST C15X40 1 2 TA ST MC8X20 Double Channels Back to back double channels, with or without spacing between them, are available. The letter D in front of the section name will specify a double channel. 21 22 24 TA D MC9X25 55 TO 60 TA D C8X18 Angles Angle specifications in STAAD are different from those in the AISC manual. The following example illustrates angle specifications.
American Steel Design 2-4 Section 2 engineers are familiar with a convention used by some other programs in which the local y-axis is the minor axis. STAAD provides for this convention by accepting the command: 54 55 56 TA RA L40356 (RA denotes reverse angle) Double Angles Short leg back to back or long leg back to back double angles can be specified by inputting the word SD or LD, respectively, in front of the angle size. In case of an equal angle either LD or SD will serve the purpose.
Section 2 Pipes Two types of specifications can be used for pipe sections. In general pipes may be input by their outer and inner diameters. For example, 1 TO 9 TA ST PIPE OD 2.0 ID 1.875 will mean a pipe with O.D. of 2.0 and I.D. of 1.875 in current input units. Pipe sections listed in the AISC manual can be specified as follows. 5 TO 10 TA ST PIPX20 PIP X 20 denotes extra strong pipe of 2 in.dia Pipe symbol 10 X Dia.
American Steel Design 2-6 Section 2 Tubes, like pipes, can be input by their dimensions (Height, Width and Thickness) as follows. 6 TA ST TUBE DT 8.0 WT 6.0 TH 0.5 is a tube that has a height of 8, a width of 6, and a wall thickness of 0.5. Member Selection cannot be performed on tubes specified in the latter way. Only code checking can be performed on these sections. Welded Plate Girders Welded plate girders from the AISC manual may be specified as follows.
Section 2 2.3 Allowables per AISC Code For steel design, STAAD compares the actual stresses with the allowable stresses as defined by the American Institute of Steel Construction (AISC) Code. The ninth edition of the AISC Code, as published in 1989, is used as the basis of this design (except for tension stress). Because of the size and complexity of the AISC codes, it would not be practical to describe every aspect of the steel design in this manual.
American Steel Design 2-8 Section 2 F b = 0.66F y If meeting the requirements of this section of: a) b f /2t f is less than or equal to 65/ Fy b) b f /t f is less than or equal to 190/ Fy c) d/t is less than or equal to 640(1-3.74(f a /F y ))/ Fy when (f a /F y ) < 0.16, or than 257/ Fy if (f a /F y ) >0.16 d) The laterally unsupported length shall not exceed 76.
Section 2 2.3.5 Combined Compression and Bending Members subjected to both axial compression and bending stresses are proportioned to satisfy AISC formula H1-1 and H1-2 when f a /F a is greater than 0.15, otherwise formula H1-3 is used. It should be noted that during code checking or member selection, if f a /F a exceeds unity, the program does not compute the second and third part of the formula H1-1, because this would result in a misleadingly liberal ratio.
American Steel Design 2-10 Section 2 Methodology If the user were to request design for torsion, the torsional properties required for calculating the warping normal stresses, warping shear stresses and pure shear stresses are first determined. These depend of the ”boundary” conditions that prevail at the ends of the member. These boundary conditions are defined as “Free”, “Pinned” or “Fixed”.
Section 2 Restrictions This facility is currently available for Wide Flange shapes (W, M & S), Channels, Tee shapes, Pipes and Tubes. It is not available for Single Angles, Double Angles, members with the PRISMATIC property specification, Composite sections (Wide Flanges with concrete slabs or plates on top), or Double Channels. Also, the stresses are calculated based on the rules for concentrated torsional moments acting at the ends of the member. 2.3.
American Steel Design 2-12 Section 2 the particular design requirements of an analysis, some or all of these parameter values may have to be changed to exactly model the physical structure. For example, by default the KZ (k value in local z-axis) value of a member is set to 1.0, while in the real structure it may be 1.5. In that case, the KZ value in the program can be changed to 1.5, as shown in the input instructions (Section 6). Similarly, the TRACK value of a member is set to 0.
Section 2 Table 2.1 - AISC Parameters Parameter Name Default Value Description KX 1.0 K value used in computing KL/r for flexural torsional buckling for tees and double angles LX Member Length L value used in computing KL/r for flexural torsional buckling for tees and double angles KY 1.0 K value in local y-axis. Usually, this is minor axis. KZ 1.0 K value in local z-axis. Usually, this is major axis. LY Member Length Length to calculate slenderness ratio for buckling about local Y axis.
American Steel Design 2-14 Section 2 Table 2.1 - AISC Parameters Parameter Name STIFF Default Value Description Member length or depth of beam whichever is greater Spacing of stiffeners for plate girder design TRACK 0.0 Controls the level of detail to which results are reported. 0 = Minimum detail 1 = Intermediate detail level 2 = Maximum detail (see Figure2.1) DMAX 1000 in. Maximum allowable depth. DMIN 0.0 in. Minimum allowable depth. RATIO 1.
Section 2 Table 2.1 - AISC Parameters Parameter Name Default Value Description DJ2 End Joint of member Joint No. denoting end point for calculation of "Deflection Length" (See Note 1) CAN 0 0 = deflection check based on the principle that maximum deflection occurs within the span between DJ1 and DJ2. 1 = deflection check based on the principle that maximum deflection is of the cantilever type (see note below) TORSION 0.0 0.0 = No torsion check performed. 1.
American Steel Design 2-16 Section 2 NOTES: 1) When performing the deflection check, the user can choose between two methods. The first method, defined by a value 0 for the CAN parameter, is based on the local displacement. Local displacement is described in section 5.43 of this manual. If the CAN parameter is set to 1, the check will be based on cantilever style deflection.
Section 2 1 2 1 3 2 EXAMPLE : 4 3 D D = Maximum local deflection for members 1 2 and 3. PARAMETERS DFF 300. ALL DJ1 1 ALL DJ2 4 ALL 3) If DJ1 and DJ2 are not used, "Deflection Length" will default to the member length and local deflections will be measured from the original member line. 4) It is important to note that unless a DFF value is specified, STAAD will not perform a deflection check. This is in accordance with the fact that there is no default value for DFF (see Table 2.1).
American Steel Design 2-18 Section 2 the user provides CMY, the program will use that value and not calculate CMY at all, regardless of what the user defines SSY to be. Figure 2.1 - Terms used in calculating slenderness ratios KL/r for local Y and Z axes 7) For a T shape which is cut from a parent I, W, S, M or H shapes, the PROFILE parameter should be assigned a value corresponding to the parent shape. For example, if the T desired is an American WT6, specify W12 for the PROFILE parameter. 2.
Section 2 When code checking is selected, the program calculates and prints whether the members have passed the code or have failed; the critical condition of the AISC code (like any of the AISC specifications or compression, tension, shear, etc.); the value of the ratio of the critical condition (overstressed for a value more than 1.
American Steel Design 2-20 Section 2 Member selection cannot be performed on members whose section properties are input as prismatic. 2.6.1 Member Selection by Optimization See Section 5.47.4 Steel table properties of an entire structure can be optimized by STAAD. The method used in the optimization, which takes place if the SELECT OPTIMIZE command is specified, involves the following steps. a. b. c. d. e.
Section 2 member rather than as a regular frame member with both ends pinned. 2.8 Unsymmetric Sections For unsymmetric sections like single angles, STAAD considers the smaller section modulus for calculating bending stresses. For single angles, the “specification for allowable stress design of single-angle members”, explained in pages 5-309 to 5-314 of the AISC-ASD 9 th edition manual has been incorporated. 2.9 Composite Beam Design as per AISC-ASD In section 1.7.
American Steel Design 2-22 Section 2 The following parameters have been introduced to support the composite member design, specified using the explicit definition method. Table 2.
Section 2 UNIT INCH PARAMETER CODE AISC BEAM 1 ALL TRACK 2 ALL DR1 0.3135 ALL WID 69.525 ALL FPC 3.0 ALL THK 4.0 ALL CMP 1 ALL CHECK CODE ALL SELECT ALL 2.10 Plate Girders Plate girders may be designed according to Chapter G of the AISC specifications. The generalized ISECTION specification capability available in the User Table facility may be used to specify the plate girder sections.
American Steel Design 2-24 Section 2 a) MEMBER refers to the member number for which the design is performed. b) TABLE refers to the AISC steel section name which has been checked against the steel code or has been selected. c) RESULT prints whether the member has PASSed or FAILed. If the RESULT is FAIL, there will be an asterisk (*) mark in front of the member number. d) CRITICAL COND refers to the section of the AISC code which governed the design.
Section 2 Fey = Fez = 12 π Ε 2 23( K Y L Y rY ) 2 12 π 2Ε 23( K Z L Z rZ ) 2 STAAD.Pro MEMBER SELECTION - (AISC 9TH EDITION) ************************** |--------------------------------------------------------------------------| | Y PROPERTIES | |************* | IN INCH UNIT | | * |=============================| ===|=== ------------ | |MEMBER 2 * | | | AX = 8.85 | | * | ST W14X30 | | --Z AY = 3.39 | |DESIGN CODE * | | | AZ = 3.47 | | AISC-1989 * =============================== ===|=== SY = 5.
American Steel Design 2-26 Section 2 2.12 Weld Design Selected provisions of the AISC specifications for the Design, Fabrication and Erection of Steel for Buildings, 1999, and the American Welding Society D1.1 Structural Welding Code – Steel, 1998, have been implemented. See Section 5.47.5 STAAD is able to select weld thickness for connections and tabulate the various stresses.
Section 2 Horizontal Stress - as produced by the local z-shear force and torsional moment. Vertical Stress - as produced by the axial y-shear force and torsional moment. Direct Stress - as produced by the axial force and bending moments in the local y and z directions. The Combined Stress is calculated by the square root of the summation of the squares of the above three principal stresses.
American Steel Design 2-28 Section 2 Vertical stress, Fv = Direct stress, Fd = VY AX FX AX + + CV × MX JW MZ * SZ + MY * SY * The moments MY and MZ are taken as absolute values, which may result in some conservative results for asymmetrical sections like angle, tee and channel. 2 2 2 Combined force Fcomb = Fh + Fv + Fd Weld thickness = Fcomb Fw where F w = Allowable weld stress, default value is 0.4 FYLD (Table 2.1).
Section 2 P Figure 2.4 - Weld design for SELECT WELD TRUSS. 2.13 Steel Design per AASHTO Specifications The design of structural steel members in accordance with the AASHTO Standard Specifications for Highway Bridges, 17 th edition has been implemented. General Comments The section of the above code implemented in STAAD is Chapter 10, Part C – Service Load design Method, Allowable Stress design. Sections 10.32.1.A and 10.36 are implemented.
American Steel Design 2-30 Section 2 manual) and Composite beams (I shapes with concrete slab on top) is not suppported. Allowable Stresses per AASHTO Code The member design and code checking in STAAD is based upon the allowable stress design method. It is a method for proportioning structural members using design loads and forces, allowable stresses, and design limitations for the appropriate material under service conditions.
Section 2 It can be mentioned here that AASHTO does not have a provision for increase in allowable stresses for a secondary member and when 1/r exceeds a certain value. Bending Stress Allowable stress in bending compression for rolled shape girders and built-up sections whose compression flanges are supported laterally through their full length by embedment in concrete is given by Fb = 0.
American Steel Design 2-32 Section 2 Bending-Axial Stress Interaction Members subjected to both axial and bending stresses are proportioned according to section 10.36 of the AASHTO steel code. All members subject to bending and axial compression are required to satisfy the following formula: fa Fa + C mx f bx (1 − f a / Fex ) Fbx + C my f by (1 − f a / Fey ) Fby < 1. 0 at intermediate points, and fa . 472 Fy + f bx Fbx + f by Fby < 1. 0 at support points.
Section 2 Table 2.3 - AASHTO Design Parameters Parameter Name Default Value Description KY 1.0 K value in local y-axis. Usually, this is minor axis. KZ 1.0 K value in local z-axis. Usually, this is major axis. LY Member Length Length to calculate slenderness ratio for buckling about local Y axis. LZ Member Length Same as above except in local z-axis. 36 KSI Yield strength of steel in current units. FYLD FU Depends on FYLD Ultimate tensile strength of steel in current units. NSF 1.
American Steel Design 2-34 Section 2 Verification Problem AASHTO Steel Design. TYPE: REFERENCE: Attached step by step hand calculation as per AASHTO code. PROBLEM: Determine the allowable stresses (AASHTO code) for the members of the structure as shown in figure. Also, perform a code check for these members based on the results of the analysis. Y 15 k (WL) 2k/ft (DL + LL) 5 5 5' 7 8 9 8 2 3 10' 6 6 7 4' 4 4 16' 11' 1 3 2 1 X Figure 2.
Section 2 VERIFICATION PROBLEM HAND CALCULATION Manual / Code refers to AASHTO Manual . Steel Design Member 1 , Size W 12X26, L = 10 ft., a = 7.65 in 2 , Sz = 33.39 in 3 From observation Load case 1 will govern, Fx = 25.0 kip (compression), Mz = 56.5 k-ft Allowable Stress Calculation: From Table 10.32.1A, Bending Minor Axis: Allowable minor axis bending stress: FTY = FTZ = 0.55 x F Y = 19.8 ksi Bending Major Axis: 2 Fcz 50 x106 Cb ⎛ I yc ⎞ J ⎛d ⎞ = + 9.87 ⎜ ⎟ ≤ 0.55Fy ⎜ ⎟ 0.
American Steel Design 2-36 Section 2 2 Fcz = 50 × 106 × 1.75 ⎛ 8.6564 ⎞ 0.28389 ⎛ 11.46 ⎞ + 9.87 ⎜ ⎜ ⎟ 0.772 ⎟ = 33.38789 ⎝ 120 ⎠ 8.6564 ⎝ 120 ⎠ 64375.03 psi From this, calculated FCZ = 64.37.As this is larger than 0.55xF Y FCZ = 0.55xF Y = 19.8 ksi Axial Compression: Critical (kL/r) y = 1.0 x 120/1.5038 = 79.7978 Cc = 2π 2 E = Fy As (kL/r) y < 2π 2 * 29000 = 126.099 36 C c , the allowable axial stress in compression 2 2 Fy ⎡ ( KL r ) Fy ⎤ 36 ⎡ ( 79.79 ) 36 ⎤ ⎢1 − ⎥= Fa = ⎢1 − ⎥ = 13.
Section 2 Fez = π 2E F .S . ( KL r ) 2 = π 2 * 29000 ⎛ 120 ⎞ 2.12 ⎜ ⎟ ⎝ 5.17 ⎠ 2 2-37 = 250.5999 From table 10-36A, C mz = 0.85 Equation 10-42 Cmy f by fa Cmx fbz 3.26 0.85* 20.299 + + = + + 0 = 1.122 3.26 ⎞ Fa ⎛ 13.58 ⎛ ⎛ fa ⎞ fa ⎞ ⎜1⎟19.8 ⎜1 − ⎟ Fbz ⎜⎜1 − ⎟⎟ Fby ⎝ 250.599 ⎠ F ' ⎝ F 'ez ⎠ ey ⎝ ⎠ For the end section, Equation 10-43 f fa f 3.26 20.299 + bz + by = + + 0 = 1.217 0.472 Fy Fbz Fby 0.472 * 36 19.8 The value calculated by STAAD is 1.218 Member 2 , Size W 12X26, L = 5 ft., a = 7.
American Steel Design 2-38 Section 2 Bending Minor Axis: Allowable minor axis bending stress: FTY = FTZ = 0.55 x F Y = 19.8 ksi Bending Major Axis: 2 Fcz 50 x106 Cb ⎛ I yc ⎞ J ⎛d ⎞ = + 9.87 ⎜ ⎟ ≤ 0.55Fy ⎜ ⎟ 0.772 S xc I yc ⎝l⎠ ⎝ l ⎠ Where, C b = 1.75+ 1.05(M1/M2)+0.3x(M1/M2) 2 Here M1 = 39.44, M2 = 677.96 so C b = 1.69 S zc =Section modulus w.r.t. compression flange =204/(0.5X12.22) = 33.38789 in 3 I YC = tb 3 /12 = 0.38 x 6.49 3 /12 = 8.6564 in 4 J = (2 x 6.49x0.38 3 + (12.22 – 2x0.38)x0.
Section 2 As (KL/r) y < 2-39 C c , the allowable axial stress in compression 2 2 Fy ⎡ ( KL r ) Fy ⎤ 36 ⎡ ( 39.92 ) 36 ⎤ ⎢1 − ⎥= Fa = ⎢1 − ⎥ = 16.13 4π 2 E ⎥ 2.12 ⎢ 4π 2 29000 ⎥ F .S . ⎢ ⎣ ⎦ ⎣ ⎦ Shear: Allowable shear stress as per gross section, F v = 0.33xF Y = 11.8 ksi Actual Stress Calculation: Axial stress (f a ) = 8.71 / 7.65 = 1.138 ksi. The critical moment occurs at the end node of the beam. So we use the AASHTO equation 10.42 in section 10-36 to calculate the design ratio.
American Steel Design 2-40 Section 2 for the end section, Equation 10-43 f fa f 1.138 20.299 + bz + by = + + 0 = 1.092 0.472 Fy Fbz Fby 0.472 * 36 19.8 The value calculated by STAAD is 1.093 Member 3 , Size W 14X43, L = 11 ft., a = 12.6 in 2 , Sz = 62.7 in 3 From observation Load case 3 will govern, Forces at the end are Fx = 25.5 kip (compression), Mz = 112.17 k-ft Allowable Stress Calculation: From Table 10.32.1A, Bending: Minor Axis: Allowable minor axis bending stress: FTY = FTZ = 0.
Section 2 3 3 4 I YC = tb /12 = 0.53 x 8.0 /12 = 22.61in J = (2 x 8.0x0.53 3 + (13.66 – 2x0.53)x0.305 3 )/3 = 0.913 in 4 2 Fcz 50 × 106 × 1.75 ⎛ 22.61 ⎞ 0.917 ⎛ 12.6 ⎞ = + 9.87 ⎜ ⎜ ⎟ 0.772 ⎟ = 83 62.7 22.61 ⎝ 132 ⎠ ⎝ 132 ⎠ 187.61 psi Since FCZ is larger than 0.55xF Y, FCZ = 0.55xF Y = 19.8 ksi Axial Compression: Critical (KL/r) y = 1.0 x 11x12/1.894 = 69.69 Cc = 2π 2 E = Fy As (KL/r) y < 2π 2 * 29000 = 126.099 36 C c , the allowable axial stress in compression 2 2 Fy ⎡ ( KL r ) Fy ⎤ 36 ⎡ ( 69.
American Steel Design 2-42 Section 2 Fez = π 2E F .S . ( KL r ) 2 = π 2 * 29000 2.12 ( 22.648 ) 2 = 263.18 From table 10-36A, C mz = 0.85 So the design ratio is Equation 10-42 Cmy f by fa Cmx fbz 2.024 0.85* 21.467 + + = + + 0 = 1.069 2.024 ⎞ Fa ⎛ 14.387 ⎛ ⎛ fa ⎞ fa ⎞ ⎜1⎟19.8 ⎜1 − ⎟ Fbz ⎜⎜1 − ⎟⎟ Fby 263.209 ⎝ ⎠ F ' F ' ez ⎠ ⎝ ey ⎠ ⎝ for the end section, Equation 10-43 f fa f 2.024 21.467 + bz + by = + + 0 = 1.203 0.472 Fy Fbz Fby 0.472 * 36 19.8 The value calculated by STAAD is 1.
Section 2 FTY = FTZ = 0.55 x F Y = 19.8 ksi Major Axis: 2 Fcz = 50 x106 Cb ⎛ I yc ⎞ J ⎛d ⎞ + 9.87 ⎜ ⎟ ≤ 0.55Fy ⎜ ⎟ 0.772 S xc I yc ⎝l⎠ ⎝ l ⎠ Where, C b = 1.75+ 1.05(M1/M2)+0.3x(M1/M2) 2 Here M1 = -191.36 Kip-in , M2 = -1346.08 Kip-in so C b = 1.606 S zc =Section modulus w.r.t. compression flange =428/(0.5X13.66) = 62.7 in 3 I YC = tb 3 /12 = 0.53 x 8.0 3 /12 = 22.61in 4 J = (2 x 8.0x0.53 3 + (13.66 – 2x0.530)x0.305 3 )/3 = 0.911 in 4 2 Fcz 50 × 106 × 1.606 ⎛ 22.61 ⎞ 0.911 ⎛ 12.6 ⎞ = + 9.87 ⎜ ⎜ ⎟ 0.
American Steel Design 2-44 Section 2 The critical moment occurs at the end node of the beam. So we use the AASHTO equation 10.42 in section 10-36 to calculate the design ratio. Actual bending stress = 112.17 x12/62.7 = 1.789 x 12 = 21.467 ksi f a f bz f by 0.6944 21.467 + + = + + 0 = 1.119 19.8 19.8 Fa Fbz Fby f fa f 0.6944 21.467 + bz + by = + + 0 = 1.125 0.472 Fy Fbz Fby 0.472 * 36 19.8 The value calculated by STAAD is 1.126 Member 5 , Size W 16X36, L = 5 ft., a = 10.6 in 2 , Sz = 56.
Section 2 Where, C b = 1.75+ 1.05(M1/M2)+0.3x(M1/M2) 2 Here M1 = 40.14, M2 = -684.4 so C b = 1.81 S zc =Section modulus w.r.t. compression flange =448/(0.5X15.86) = 56.5 in 3 I YC = tb 3 /12 = 0.43 x 6.99 3 /12 = 12.238 in 4 J = (2 x 6.99x0.43 3 + (15.86 – 2x0.43)x0.29 3 )/3 = 0.5 in 4 2 Fcz 50 × 106 × 1.81 ⎛ 12.238 ⎞ 0.5 ⎛ 15 ⎞ = + 9.87 ⎜ ⎟ = 2 ⎜ ⎟ 0.772 56.5 12.238 ⎝ 60 ⎠ ⎝ 60 ⎠ 63079 psi Since FCZ is larger than 0.55xF Y, FCZ = 0.55xF Y = 19.8 ksi Axial Compression: Critical (KL/r) y = 1.
American Steel Design 2-46 Section 2 Actual Stress Calculation: Axial stress (f a ) = 14.02 / 10.6 = 1.323 ksi. The critical moment occurs at the end node of the beam. So we use the AASHTO equation 10.42 in section 10-36 to calculate the design ratio. Actual bending stress = 57.04 x12/56.5 = 1.001 x 12 = 12.115 ksi (KL/r) z = 1x60/6.5= 9.231 Fez = π 2E F .S . ( KL r ) 2 = π 2 * 29000 2.12 ( 9.231) 2 = 1584.398 From table 10-36A, C mz = 0.
Section 2 Member 6 , Size W 16X36, L = 16 ft., a = 10.6 in 2 , Sz = 56.5 in 3 From observation Load case 3 will govern, Forces at the end are Fx = 10.2 kip (compression), Mz = 62.96 k-ft Allowable Stress Calculation: From Table 10.32.1A, Bending: Minor Axis: Allowable minor axis bending stress: FTY = FTZ = 0.55 x F Y = 19.8 ksi Major Axis: 2 Fcz 50 x106 Cb ⎛ I yc ⎞ J ⎛d ⎞ = + 9.87 ⎜ ⎟ ≤ 0.55Fy ⎜ ⎟ 0.772 S xc I yc ⎝l⎠ ⎝ l ⎠ Where, C b = 1.75+ 1.05(M1/M2)+0.3x(M1/M2) 2 Here M1 = 8.947 M2 = 183.
American Steel Design 2-48 Section 2 Since FCZ is larger than 0.55xF Y, FCZ = 0.55xF Y = 19.8 ksi Axial Compression: Critical (KL/r) y = 1.0 x 192/1.52 = 126.29 2π 2 E = Fy Cc = As (KL/r) y Fa = > 2π 2 * 29000 = 126.099 36 C c , the allowable axial stress in compression π 2E F .S . ( KL r ) = 2 π 2 *29000 2.12* (126.29 ) 2 = 8.46 ksi Shear: Allowable shear stress as per gross section, F v = 0.33xF Y = 11.8 ksi Actual Stress Calculation: Axial stress (f a ) = 10.2 /10.6 = 0.962ksi.
Section 2 2-49 So the design ratio is Cmy f by fa Cmx fbz 0.962 0.85*13.372 + + = + + 0 = 0.691 Fa ⎛ 8.46 ⎛ ⎛ 0.926 ⎞ fa ⎞ fa ⎞ ⎜1⎟19.8 ⎜1 − ⎟ Fbz ⎜⎜1 − ⎟⎟ Fby 154.58 ⎠ ⎝ F ' ⎝ F 'ez ⎠ ey ⎠ ⎝ f fa f 0.962 13.372 + bz + by = + + 0 = 0.732 0.472 Fy Fbz Fby 0.472*36 19.8 The value calculated by STAAD is 0.732 Member 7 , Size W 16X36, L = 4 ft., a = 10.6 in 2 , Sz = 56.5 in 3 From observation Load case 3 will govern, Forces at the midspan are Fx = 24.05 kip (tension), Mz = 62.
American Steel Design 2-50 Section 2 Axial Tension: F a = 0.55 x F Y = 19.8 ksi Shear: Allowable shear stress as per gross section, F v = 0.33xF Y = 11.8 ksi Actual Stress Calculation: Actual stress (f a ) = 24.05 /10.6 = 2.268 ksi, hence safe. From Table 10.32.1A, Allowable stress in bending(compression) The critical moment occurs at the end node of the beam. So we use the AASHTO equation 10.42 in section 10-36 to calculate the design ratio. Actual bending stress = 62.96 x12/56.5 = 1.11433 x 12 = 13.
Section 2 Allowable Stress Calculation: Axial Compression: Critical (KL/r) y = 1.0 x 7.07x12/0.795 = 106.73 Cc = 2π 2 E = Fy As (KL/r) y < 2π 2 * 29000 = 126.099 36 C c , the allowable axial stress in compression 2 2 Fy ⎡ ( KL r ) Fy ⎤ 36 ⎡ (106.73) 36 ⎤ ⎢1 − ⎥= Fa = ⎢1 − ⎥ = 10.89 4π 2 E ⎥ 2.12 ⎢ 4π 2 29000 ⎥ F .S . ⎢ ⎣ ⎦ ⎣ ⎦ ksi Actual Stress Calculation: Actual stress (f a ) = 23.04 /1.938 = 11.88 ksi. Ratio f a 11.88 = = 1.09 Fa 10.89 The value calculated by STAAD is 1.
American Steel Design 2-52 Section 2 Cc = 2π 2 E = Fy As (KL/r) y < 2π 2 * 29000 = 126.099 36 C c , the allowable axial stress in compression 2 2 Fy ⎡ ( KL r ) Fy ⎤ 36 ⎡ ( 68.57 ) 36 ⎤ ⎢1 − ⎥= Fa = ⎢1 − ⎥ = 14.47 k 4π 2 E ⎥ 2.12 ⎢ 4π 2 29000 ⎥ F .S . ⎢ ⎣ ⎦ ⎣ ⎦ si Actual Stress Calculation: Actual stress (f a ) = 48.44 /3.61 = 13.42 ksi. Ratio f a 13.42 = = 0.927 Fa 14.47 The value calculated by STAAD is 0.
Section 2 **************************************************** * * * STAAD.Pro * * Version Bld * * Proprietary Program of * * Research Engineers, Intl. * * Date= * * Time= * * * * USER ID: * **************************************************** 1. 2. 3. 4. 5. 6. 7. 8. 9. 11. 12. 13. 15. 16. 17. 19. 21. 22. 23. 24. 26. 27. 29. 30. 31. 33. STAAD PLANE VERIFICATION PROBLEM FOR AASHTO CODE * * THIS DESIGN EXAMPLE IS VERIFIED BY HAND CALCULATION * FOLLOWING AASHTO ASD 97 CODE.
American Steel Design 2-54 Section 2 35. PRINT FORCES MEMBER END FORCES STRUCTURE TYPE = PLANE ----------------ALL UNITS ARE -- KIP FEET MEMBER 1 LOAD JT AXIAL SHEAR-Y SHEAR-Z TORSION MOM-Y MOM-Z 1 1 3 1 3 25.00 -25.00 12.00 -12.00 -5.65 5.65 1.05 -1.05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 -56.50 0.00 10.52 3 5 3 5 8.71 -8.71 15.83 -15.83 10.64 -10.64 -2.77 2.77 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 56.50 -3.29 -10.52 -3.
Section 2 40. CHECK CODE ALL STAAD.Pro CODE CHECKING - (AASH) *********************** ALL UNITS ARE - KIP MEMBER FEET (UNLESS OTHERWISE NOTED) RESULT/ CRITICAL COND/ RATIO/ LOADING/ FX MY MZ LOCATION ======================================================================= * 1 TABLE ST W12X26 FAIL 25.00 C * 2 ST W12X26 * 3 ST W14X43 * 4 ST W14X43 5 ST W16X36 FAIL 8.71 C FAIL 25.50 C FAIL 8.75 T PASS 14.02 C 6 ST W16X36 PASS 10.20 C 7 ST W16X36 PASS 24.06 T * 8 ST L40404 FAIL 23.
American Steel Design 2-56 Section 2 2.14 Steel Design per AISC/LRFD Specification The 2 nd and 3 rd editions of the American LRFD code have been implemented. The commands to access those respective codes are: For the 3 rd edition code – PARAMETER CODE LRFD or PARAMETER CODE LRFD3 For the 2 nd edition – PARAMETER CODE LRFD2 2.14.1 General Comments The design philosophy embodied in the Load and Resistance Factor Design (LRFD) Specification is built around the concept of limit state design.
Section 2 In the STAAD implementation of LRFD, members are proportioned to resist the design loads without exceeding the limit states of strength, stability and serviceability. Accordingly, the most economic section is selected on the basis of the least weight criteria as augmented by the designer in specification of allowable member depths, desired section type, or other such parameters.
American Steel Design 2-58 Section 2 the live load and other loads in comparison with the dead load, a uniform reliability is not possible. LRFD, as its name implies, uses separate factors for each load and resistance. Because the different factors reflect the degree of uncertainty of different loads and combinations of loads and of the accuracy of predicted strength, a more uniform reliability is possible.
Section 2 Sect. C1 of the LRFD specification, an analysis of second order effects is required. Thus, when using LRFD code for steel design, the user must use the P-Delta analysis feature of STAAD. 2.14.4 Section Classification The LRFD specification allows inelastic deformation of section elements. Thus local buckling becomes an important criterion. Steel sections are classified as compact, noncompact or slender element sections depending upon their local buckling characteristics.
American Steel Design 2-60 Section 2 2.14.6 Axial Compression The column strength equations have been revised in LRFD to take into account inelastic deformation and other recent research in column behavior. Two equations governing column strength are available, one for inelastic buckling and the other for elastic or Euler buckling. Both equations include the effects of residual stresses and initial out-of-straightness.
Section 2 2.14.7 Flexural Design Strength In LRFD, the flexural design strength of a member is determined by the limit state of lateral torsional buckling. Inelastic bending is allowed and the basic measure of flexural capacity is the plastic moment capacity of the section. The flexural resistance is a function of plastic moment capacity, actual laterally unbraced length, limiting laterally unbraced length, buckling moment and the bending coefficient.
American Steel Design 2-62 Section 2 2.14.10 Design Parameters Design per LRFD specifications is requested by using the CODE parameter (see Section 5.47). Other applicable parameters are summarized in Table 2.2. These parameters communicate design decisions from the engineer to the program and thus allow the engineer to control the design process to suit an application's specific needs. See Table 2.2 and Section 5.47.
Section 2 2-63 Table 2.4 - AISC LRFD Parameters Parameter Name Default Value Description UNT Member Length Unsupported length (Lb ) of the top* flange for calculating flexural strength. Will be used only if flexural compression is on the top flange. UNB Member Length Unsupported length (Lb ) of the bottom* flange for calculating flexural strength. Will be used only if flexural compression is on the bottom flange.
American Steel Design 2-64 Section 2 Table 2.4 - AISC LRFD Parameters Parameter Name PROFILE Default Value Description None Used in member selection. See section 5.47.1 for details. AXIS 1 1 - Design single angles for bending based on principal axis. 2 - Design single angles for bending based on geometric axis. FLX 1 1 – Single Angle Member is not fully braced against lateral torsional buckling. 2 - Single Angle Member is fully braced against lateral torsional buckling.
Section 2 Example for the LRFD-2001 code UNIT KIP INCH PARAMETER CODE LRFD or CODE LRFD3 FYLD 50 ALL UNT 72 MEMBER 1 TO 10 UNB 72 MEMB 1 TO 10 MAIN 1.0 MEMB 17 20 SELECT MEMB 30 TO 40 CHECK CODE MEMB 1 TO 30 Example for the LRFD-1994 code UNIT KIP INCH PARAMETER CODE LRFD2 FYLD 50 ALL UNT 72 MEMBER 1 TO 10 UNB 72 MEMB 1 TO 10 MAIN 1.0 MEMB 17 20 SELECT MEMB 30 TO 40 CHECK CODE MEMB 1 TO 30 2.14.
American Steel Design 2-66 Section 2 If the TRACK is set to 1.0, member design strengths will be printed out. 2.14.13 Composite Beam Design per the American LRFD 3rd edition code The design of composite beams per the 3 rd edition of the American LRFD code has been implemented. The salient points of this feature are as follows: b = effective width Reinforced-concrete slab t = thickness of slab Rib Height AS = Area of Steel Beam f C = Ult. Compressive Strength of Concrete Figure 2.
Section 2 3. 2-67 If step 1 produces a higher value than step 2, plastic neutral axis (PNA) is in the slab. Else, it is in the steel beam. CASE 1: PNA IN SLAB Find the depth of PNA below the top of slab as: 0.85 f c . b . a . = A s . f y a= As . f y 0.85 f c . b fC a hr P.N.A. C t fy e d/2 d T d/2 fy Figure 2.7 Lever arm e = d a + hr + t − 2 2 ( ) Moment capacity = φ b A s . f y .
American Steel Design 2-68 Section 2 CASE 2: PNA IN STEEL BEAM Define: C s = Compressive force in slab = 0.85 . f c . b . t C b = Compressive force in steel beam T b = Tensile force in steel beam Cs + Cb = Tb Since magnitude of C b + magnitude of T b = A s . f y Substituting for T b as (A s . f y – C b ), we get: Cs + Cb = As . f y – Cb C b = (A s . f y – C s ) x 0.5 Determine whether the PNA is within the top flange of steel beam, or inside its web.
Section 2 CASE 2A: PNA IN FLANGE OF STEEL BEAM fC CS t hr fy fy y Cf e2 e1 P.N.A. Tb fy Figure 2.8 Calculate: y= Cf (b f . f y ) where, b f = width of flange The point of action of the tensile force is the centroid of the steel area below the PNA. After finding that point, e 1 and e 2 can be calculated. Moment Capacity = ( φ b C f . e1 + C s .
American Steel Design 2-70 Section 2 CASE 2B: PNA IN WEB OF STEEL BEAM fC CS t hr fy Cf Cw g e3 e2 e1 P.N.A. TS fy Figure 2.9 C f = Compressive force in flange = A f . f y C w = Compressive force in web = C b – C f g= Cw (t w . f y ) where, t w = thickness of web Point of action of the tensile force is the centroid of the steel area below the PNA. After finding that point, e 1 , e 2 and e 3 can be calculated. ( Moment Capacity = φ b C s . e 2 + C f . e1 + C w .
Section 2 Notes 1. Rib Height is the distance from top of flange of steel beam to lower surface of concrete. 2. If the slab is flush on top of the steel beam, set the Rib Height to zero. Reinforced-concrete slab Rib Height Figure 2.10 3. For moments which cause tension in the slab (called positive moments in STAAD convention), design of the beam is presently not carried out. 4. Shear connectors are presently not designed. 5. Member selection is presently not carried out. 6.
American Steel Design 2-72 Section 2 TABLE 2.5 – COMPOSITE BEAM DESIGN PARAMETERS FOR AISC-LRFD Name Default value RBH 0.0 inches Description Rib Height EFFW Value used in analysis Effective width of slab FPC Value used in analysis Ultimate compressive strength of concrete Example STAAD SPACE … … MEMBER PROPERTY 1 TA CM W12X26 CT 6.0 FC 4.0 CW 40.0 … … PERFORM ANALYSIS … … PARAMETER CODE LRFD RBH 5.
Section 2 2.15 Design per American Cold Formed Steel Code General Provisions of the AISI Specification for the Design of ColdFormed Steel Structural Members, 1996 Edition have been implemented. The program allows design of single (noncomposite) members in tension, compression, bending, shear, as well as their combinations using the LRFD Method. For flexural members, the Nominal Section Strength is calculated on the basis of initiation of yielding in the effective section (Procedure I).
American Steel Design 2-74 Section 2 designation symbol in the input file. Details of the latter are explained below. The AISI Steel Section Library: The command-line syntax for assigning steel sections from the AISI library is as explained below : C-Section With Lips 20 TO 30 TA ST 14CS3.75X135 33 36 TA ST 12CS1.625X102 42 43 TA ST 4CS4X060 C-Section Without Lips 50 TO 60 TA ST 10CU1.25X071 32 33 TA ST 3CU1.25X057 21 28 TA ST 1.5CU1.25X035 Z-Section With Lips 1 3 4 TA ST 12ZS3.
Section 2 Equal Leg Angles With Lips 8 9 TA ST 4LS4X105 10 11 TA ST 3LS3X060 12 13 TA ST 2LS2X075 Equal Leg Angles Without Lips 1 5 TA ST 4LU4X135 7 8 TA ST 2.5LU2.5X105 4 9 TA ST 2LU2X060 Hat Sections Without Lips 4 8 TA ST 10HU5X075 5 6 TA ST 6HU9X105 1 7 TA ST 3HU4.5X135 Current Limitations : At the present time, only standard single sections are available for specification.
American Steel Design 2-76 Section 2 Design Procedure The following two design modes are available: 1. Code Checking The program compares the resistance of members with the applied load effects, in accordance with the LRFD Method of the AISI code. Code checking is carried out for locations specified by the user via the SECTION command or the BEAM parameter. The results are presented in a form of a PASS/FAIL identifier and a RATIO of load effect to resistance for each member checked.
Section 2 Cross-sectional properties of members are checked for compliance with the following Sections: • • B1.1(a), Maximum Flat-Width-to-Thickness Ratios, and B1.2, Maximum Web Depth-to-Thickness Ratio The program checks member strength in accordance with Chapter C of the specification as follows: 1. Tension Members. Resistance is calculated in accordance with Section C2. 2. Flexural Members. a) C3.1, Strength for bending only: • C3.1.1, Nominal Section Strength, Procedure I • C3.1.
American Steel Design 2-78 Section 2 The following table contains the input parameters for specifying values of design variables and selection of design options. Table 2.6 - AISI Cold Formed Steel Design Parameters Parameter Name Default Value Description BEAM 1.0 When this parameter is set to 1.0 (default), the adequacy of the member is determined by checking a total of 13 equally spaced locations along the length of the member. If the BEAM value is 0.
Section 2 Table 2.6 - AISI Cold Formed Steel Design Parameters Parameter Name Default Value Description DMAX 1000.0 Maximum depth permissible for the section during member selection. This value must be provided in the current units. DMIN 0.0 Minimum depth required for the section during member selection. This value must be provided in the current units. FLX 1 Specifies whether torsional-flexural buckling restraint is provided or is not necessary for the member. See AISI C4.
American Steel Design 2-80 Section 2 Table 2.6 - AISI Cold Formed Steel Design Parameters Parameter Name Default Value Description KZ 1.0 Effective length factor for overall column buckling in the local Z-axis. It is a fraction and is unit-less. Values can range from 0.01 (for a column completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the capacity in axial compression. LT Member length Unbraced length for twisting.
Section 2 Table 2.6 - AISI Cold Formed Steel Design Parameters Parameter Name Default Value Description STIFF Member length Spacing in the longitudinal direction of shear stiffeners for reinforced web elements. It is input in the current units of length. See section AISI C3.2 0 This parameter is used to control the level of detail in which the design output is reported in the output file. The allowable values are: TRACK 0 - Prints only the member number, section name, ratio, and PASS/FAIL status.
American Steel Design 2-82 Section 2 2.16 Castellated Beams STAAD.Pro comes with the non-composite castellated beam tables supplied by the steel products manufacturer SMI Steel Products. Details of the manufacture and design of these sections may be found at http://www.smisteelproducts.com/English/About/design.html Figure 2.
Section 2 Analysis and Design criteria The local axis system (local X, local Y and local Z) of a castellated beam is identical to that for a wide flange, and is shown in section 1.5.2 of the Technical Reference manual. User’s have to recognize that there are two basic issues to be understood with regard to these members a) analysis b) steel design We first explain the design issues because only then will their relationship with the analysis issues become apparent.
American Steel Design 2-84 Section 2 The design method is the allowable stress method, using mainly the rules stated in the AISC ASD 9 th edition code. Only code checking is currently available for castellated beams. Member selection is not. Design parameters: The following table contains a list of parameters and their default values. Table 2.7 Parameter Default Value Description SOPEN 1.5e + b is the minimum allowable value.
Section 2 2-85 Table 2.7 Parameter CMZ Default Value 0.85 Description Cm value in local Z axis. Used in the interaction equations in Chapter H of AISC specifications. TRACK 0 Parameter used to control the level of description of design output. Permissible values are 0 and 1 . RATIO 1.0 Permissible maximum ratio of actual load to section capacity. Any input value will be used to change the right hand side of governing interaction equations in Chapter H and elsewhere. References: STAAD.
American Steel Design 2-86 Section 2 member fails these checks, the remainder of the checks are not performed. The cross section checks are the following: Figure 2.13 1. Web Post Width ( e ) should be at least 3.0 inches 2. Tee Depth ( d T -top and d T -bot ) should be greater than the thickness of flange plus one inch. 3. Angle θ should be between 45 and 70 degrees. 4.
Section 2 Checking the member for adequacy in carrying the applied loading: This consists of five different checks: 1. 2. 3. 4. 5. Global Bending Vierendeel Bending Horizontal Shear Vertical Shear Web Post Buckling Design for Section considered in the design (shown with the vertical dotted lines) Vierendeel Bending Global Bending Vertical Shear Horizontal Shear Web Post Buckling Figure 2.
American Steel Design 2-88 Section 2 1. Global Bending: Global bending check is done at the web post section. This is the region of the member where the full cross section is active, without interference of the holes. The actual bending stress is computed at the middle of the web post location and is obtained by dividing the moment by the section modulus of the full section. For computing the allowable bending stress, the compactness of the section is first determined in accordance with Table B5.
Section 2 Allowable Stresses for vierendeel bending: • Axial Stress: The allowable axial stress is computed as per the Chapter E of the AISC specifications. The unsupported length for column buckling is equal to e. • Bending Stress: The allowable bending stress is computed for the top and bottom Tee section as per the Chapter F of the AISC manual. The axial stress plus bending stress is computed at the top and bottom of each tee section.
American Steel Design 2-90 Section 2 The command syntax in the STAAD input file for assigning castellated beams is: MEMBER PROPERTY AMERICAN Member-list TABLE ST section-name Example MEMBER PROPERTY AMERICAN 2 TABLE ST CB12x28 Assigning Design parameters Under the PARAMETERS block on input, the code name must be specified as: CODE AISC CASTELLATED Example PARAMETER CODE AISC CASTELLATED UNL 0.01 MEMB 25 31 FYLD 50 MEMB 25 31 SOPEN 11.
Section 2 Steel Design Output: A typical TRACK 2 level output page from the STAAD output file is as shown. Figure 2.
American Steel Design 2-92 Section 2 Viewing the design results in the graphical screens: After the analysis and design is completed, double click on the castellated member. This feature, known as member query, brings up a dialog box, one of whose tabs will be Castellated Beam Design as shown. Figure 2.
Section 2 Example Problem : STAAD PLANE EXAMPLE PROBLEM FOR *CASTELLATED BEAM DESIGN UNIT FT KIP JOINT COORDINATES 1 0. 0. ; 2 45 0 3 0 15; 4 45 15 MEMBER INCIDENCE 1 1 3; 2 3 4; 3 4 2 MEMBER PROPERTY AMERICAN 2 TA ST CB27x40 1 3 TA ST W21X50 UNIT INCH CONSTANTS E STEEL ALL DEN STEEL ALL POISSON STEEL ALL MEMBER RELEASE 2 START MX MY MZ 2 END MY MZ UNIT FT SUPPORT 1 2 FIXED LOADING 1 DEAD AND LIVE LOAD MEMB LOAD 2 UNI Y -0.
American Steel Design 2-94 Section 2 LOADING 2 WIND FROM LEFT MEMBER LOAD 2 UNI Y -0.6 LOAD COMB 3 1 1.0 2 1.0 PERFORM ANALYSIS LOAD LIST 3 PRINT MEMBER FORCES PRINT SUPPORT REACTION UNIT KIP INCH PARAMETER CODE AISC CASTELLATED UNL 0.01 MEMB 2 FYLD 50 MEMB 2 CMZ 0.85 MEMB 2 CB 1.1 MEMB 2 TRACK 2.0 ALL SOPEN 11.124 MEMB 2 EOPEN 11.
3-1 American Concrete Design Section 3 3.1 Design Operations STAAD has the capabilities for performing concrete design. It will calculate the reinforcement needed for the specified concrete section. All the concrete design calculations are based on the current ACI 318. Two versions of the code are currently implemented. The 2002 edition and the 1999 edition.
American Concrete Design 3-2 Section 3 3.2 Section Types for Concrete Design The following types of cross sections can be defined for concrete design. For Beams For Columns For Slabs Walls/Plates Prismatic (Rectangular & Square), Trapezoidal and T-shapes Prismatic (Rectangular, Square and Circular) Finite element with a specified thickness. YD ZD ZD YD YD ZD PRISMATIC YD YB ZB ZB CIRCULAR TEE TRAPEZOIDAL Figure 3.1 3.
Section 3 In the above input, the first set of members are rectangular (18 inch depth and 12 inch width) and the second set of members, with only depth and no width provided, will be assumed to be circular with 12 inch diameter. It can been seen that no area (AX) is provided for these members. For concrete design, this property must not be provided. If shear areas and moments of inertias are not provided, the program calculates these values from YD and ZD.
American Concrete Design 3-4 Section 3 generate load cases which contain loads magnified by the appropriate load factors. Table 3.1 – ACI 318 Design Parameters Parameter Name Default Value Description FYMAIN * 60,000 psi Yield Stress for main reinforcing steel. FYSEC * 60,000 psi Yield Stress for secondary steel. FC * 4,000 psi Compressive Strength of Concrete. CLT * 1.5 inch Clear cover for top reinforcement. CLB * 1.5 inch Clear cover for bottom reinforcement. CLS * 1.
Section 3 Table 3.1 – ACI 318 Design Parameters Parameter Name DEPTH Default Value *YD Description Depth of concrete member. This value defaults to YD as provided under MEMBER PROPERTIES. NSECTION *** 12 Number of equally-spaced sections to be considered in finding critical moments for beam design. TRACK 0.0 BEAM DESIGN: With TRACK set to 0.0, Critical Moment will not be printed out with beam design report. A value of 1.0 will mean a print out. A value of 2.
American Concrete Design 3-6 Section 3 3.5 Slenderness Effects and Analysis Consideration Slenderness effects are extremely important in designing compression members. The ACI-318 code specifies two options by which the slenderness effect can be accommodated (Section 10.10 & 10.11 ACI-318).
Section 3 combinations of forces and moments, whereas a primary load case is revised during the pdelta analysis based on the deflections. Also, the proper factored loads (such as 1.4 for DL etc.) should be provided by the user. STAAD does not factor the loads automatically. 3.6 Beam Design Beams are designed for flexure, shear and torsion. For all these forces, all active beam loadings are prescanned to locate the possible critical sections.
American Concrete Design 3-8 Section 3 3.6.2 Design for Shear Shear reinforcement is calculated to resist both shear forces and torsional moments. Shear forces are calculated at a distance (d+SFACE) and (d+EFACE) away from the end nodes of the beam. SFACE and EFACE have default values of zero unless provided under parameters (see Table 3.1). The value of the effective depth "d" used for this purpose accounts for the actual center of gravity of the main reinforcement calculated under flexural design.
Section 3 Example for beam design per the ACI 318-2002 code UNIT KIP INCH START CONCRETE DESIGN CODE ACI 2002 or CODE ACI FYMAIN 58 ALL MAXMAIN 10 ALL CLB 2.5 ALL DESIGN BEAM 1 7 10 END CONCRETE DESIGN Example for beam design per the ACI 318-1999 code UNIT KIP INCH START CONCRETE DESIGN CODE ACI 1999 FYMAIN 58 ALL MAXMAIN 10 ALL CLB 2.5 ALL DESIGN BEAM 1 7 10 END CONCRETE DESIGN 3.6.4 Description of Output for Beam Design Table 3.
American Concrete Design 3-10 Section 3 3) BAR INFO Reinforcement bar information specifying number of bars and bar size. 4) FROM Distance from the start of the beam to the start of the reinforcement bar. 5) TO Distance from the start of the beam to the end of the reinforcement bar. 6) ANCHOR States whether anchorage, (STA/END) either a hook or continuation, is needed at start (STA) or at the end.
Section 3 Table 3.2 (Actual Output from Design) ==================================================================== B E A M LEN - 20.00FT. N O. 14 D E S I G N FY - 60000. R E S U L T S - FC - 4000. FLEXURE SIZE - 15.00 X 21.00 INCHES LEVEL HEIGHT BAR INFO FROM TO ANCHOR FT. IN. FT. IN. FT. IN. STA END --------------------------------------------------------------------1 0 + 2-5/8 3-NUM.
American Concrete Design 3-12 Section 3 3.6.5 Cracked Moment of Inertia – ACI Beam Design When beam design is done per ACI 318, STAAD will report the moment of inertia of the cracked section at the location where the design is performed. The cracked section properties are calculated in accordance with the equations shown below. Rectangular sections Figure 3.4 Tee shaped sections Figure 3.
Section 3 A typical screen from the STAAD beam design output, showing the cracked moment of inertia value, is shown below. Figure 3.6 3.7 Column Design Columns design in STAAD per the ACI code is performed for axial force and uniaxial as well as biaxial moments. All active loadings are checked to compute reinforcement. The loading which produces the largest amount of reinforcement is called the critical load. Column design is done for square, rectangular and circular sections.
American Concrete Design 3-14 Section 3 2) Find an approximate arrangement of bars for the assumed reinforcement. 3) Calculate PNMAX = 0.85 Po, where Po is the maximum axial load capacity of the section. Ensure that the actual nominal load on the column does not exceed PNMAX. If PNMAX is less than Pu/PHI, (PHI is the strength reduction factor) increase the reinforcement and repeat steps 2 and 3. If the reinforcement exceeds 8%, the column cannot be designed with its current dimensions.
Section 3 any of the radial axes. The values printed for the TRACK 1.0 output are: P0 = Maximum purely axial load carrying capacity of the column (zero moment). Pnmax = Maximum allowable axial load on the column (Section 10.3.5 of ACI 318). P-bal = Axial load capacity at balanced strain condition. M-bal = Uniaxial moment capacity at balanced strain condition. e-bal = M-bal / P-bal = Eccentricity at balanced strain condition. M0 = Moment capacity at zero axial load.
American Concrete Design 3-16 Section 3 DESIGN COLUMN 23 25 END CONCRETE DESIGN Example for column design per the ACI 318-1999 code UNIT KIP INCH START CONCRETE DESIGN CODE ACI 1999 FYMAIN 58 ALL MAXMAIN 10 ALL CLB 2.5 ALL DESIGN COLUMN 23 25 END CONCRETE DESIGN Column Design Output The following table illustrates different levels of the column design output. Table 3.3 The following output is generated without any TRACK specification.
Section 3 TRACK 1.0 generates the following additional output. COLUMN INTERACTION: MOMENT ABOUT Z -AXIS (KIP-FT) -------------------------------------------------------P0 Pn max P-bal. M-bal. e-bal.(inch) 897.12 717.70 189.56 158.50 10.03 M0 P-tens. Des.Pn Des.Mn e/h 137.46 -432.00 323.12 9.88 0.003 -------------------------------------------------------COLUMN INTERACTION: MOMENT ABOUT Y -AXIS (KIP-FT) -------------------------------------------------------P0 Pn max P-bal. M-bal. e-bal.(inch) 897.12 717.
American Concrete Design 3-18 Section 3 3.8 Designing elements, shear walls, slabs STAAD currently provides facilities for designing 3 types of entities associated with surface type of structures. a. Individual plate elements – these are designed from the standpoint that one element is independent of the next element. See section 3.8.1 for details. b. Shear Walls – Structural components modelled using the SURFACE INCIDENCE command can be designed as shear walls. See section 3.8.2 for details. c.
Section 3 Z Y My X Mx TRANS. My Mx LONG. Figure 3.7 Table 3.4 (Actual Output from Design) ELEMENT FORCES FORCE, LENGTH UNITS= KIP FEET -------------FORCE OR STRESS = FORCE/WIDTH/THICK, MOMENT = FORCE-LENGTH/WIDTH ELEMENT LOAD QX QY MX MY MXY FX FY FXY 13 1 0.00 0.04 0.14 0.06 0.00 6.05 0.76 0.00 TOP : SMAX= 9.35 SMIN= 2.09 TMAX= 3.63 ANGLE= 0.0 BOTT: SMAX= 2.74 SMIN= -0.56 TMAX= 1.65 ANGLE= 0.0 3 0.00 0.03 0.10 0.04 0.00 2.63 0.25 1.46 TOP : SMAX= 5.44 SMIN= 0.74 TMAX= 2.35 ANGLE= 18.7 BOTT: SMAX= 1.
American Concrete Design 3-20 Section 3 Example for element design per the ACI 318-2002 code UNIT KIP INCH START CONCRETE DESIGN CODE ACI 2002 or CODE ACI FYMAIN 58 ALL MAXMAIN 10 ALL CLB 2.5 ALL DESIGN ELEMENT 43 END CONCRETE DESIGN Example for element design per the ACI 318-1999 code UNIT KIP INCH START CONCRETE DESIGN CODE ACI 1999 FYMAIN 58 ALL MAXMAIN 10 ALL CLB 2.5 ALL DESIGN ELEMENT 43 END CONCRETE DESIGN 3.8.
Section 3 The attributes associated with the surface element, and the sections of this manual where the information may be obtained, are listed below: Attributes Surfaces incidences Openings in surfaces Local coordinate system for surfaces Specifying sections for stress/force output Property for surfaces Material constants Surface loading Stress/Force output printing Shear Wall Design - Related Sections 5.13.3 5.13.3 1.6.3 5.13.3 5.21.2 5.26.3 5.32.3.4 5.42 3.8.2, 5.
American Concrete Design 3-22 Section 3 The program reports shear wall design results for each load case/combination for a user specified number of sections given by the SURFACE DIVISION (default value is 10) command. The wall is designed at these horizontal sections. The output includes the required horizontal and vertical distributed reinforcing, the concentrated (in-plane bending) reinforcing, and the links required to resist out-of-plane shear.
Section 3 The following table explains parameters used in the shear wall design command block above. All reinforcing bar sizes are English designation (#). Table 3.5 - SHEAR WALL DESIGN PARAMETERS Parameter Name FYMAIN Default Value Description 60.0 ksi Yield strength of steel, in current units. FC 4.0 ksi Compressive strength of concrete, in current units. HMIN 3 Minimum size of horizontal reinforcing bars (range 3 18).
American Concrete Design 3-24 Section 3 Table 3.5 - SHEAR WALL DESIGN PARAMETERS Parameter Name LMIN Default Value 3 LMAX 18 CLEAR 3.0 in TWOLAYERED 0 KSLENDER 1.5 Example . . . SET DIVISION 12 SURFACE INCIDENCES 2 5 37 34 SUR 1 19 16 65 68 SUR 2 11 15 186 165 SUR 3 10 6 138 159 SUR 4 . . . SURFACE PROPERTY 1 TO 4 THI 18 SUPPORTS Description Minimum size of links (range 3 - 18) Maximum size of links (range 3 - 18) Clear concrete cover, in current units.
Section 3 1 7 14 20 PINNED 2 TO 5 GEN PIN 6 TO 10 GEN PIN 11 TO 15 GEN PIN 19 TO 16 GEN PIN . . . SURFACE CONSTANTS E 3150 POISSON 0.17 DENSITY 8.68e-005 ALPHA 5.5e-006 . . .
American Concrete Design 3-26 Section 3 Notes regarding the above example: 1. Command SET DIVISION 12 indicates that the surface boundary node-to-node segments will be subdivided into 12 fragments prior to finite element mesh generation. 2. Four surfaces are defined by the SURFACE INCIDENCES command. 3. The SUPPORTS command includes the support generation feature. For instance, the line 2 TO 5 GEN PIN assigns pinned supports to all nodes between nodes 2 and 5.
Section 3 Design for in-plane shear (denoted using Fxy in the shear wall force output) per Section 11.10 of ACI 318 a. Extreme compression fiber to centroid of tension (concentrated) reinforcement distance, d, is taken as 0.8 horizontal length of the wall (ACI - 11.10.4), b. Limit on the nominal shear strength, Vn, is calculated (ACI - 11.10.3), c. Nominal shear strength of concrete is computed (11.10.6), d.
American Concrete Design 3-28 Section 3 d. Extreme compression fiber to centroid of tension reinforcement distance, d, is taken as 0.8 horizontal length of the wall (11.10.4 of ACI 318). e. Flexural design of the wall is carried out in accordance with provisions of Chapter 10. f. The flexural (concentrated) reinforcing is located at both ends (edges) of the length of the wall. Rebar layout conforms to the spacing requirements of Section 7.6.
Section 3 Description Slab Interactive Design offers the following advantages: 1. Bending and shear design, fully conforming to the ACI 318-02 Code. 2. Design based on finite element analysis - no limitations of traditional design approaches, such as the Direct Design or Equivalent Frame methods. 3. It is suitable for systems with non-uniform slab thickness. 4. Reinforcing calculations may be based on extremum or average bending moment. 5.
American Concrete Design 3-30 Section 3 compute - one of the orthogonal directions is assumed to be parallel to the design section. c. Punching shear check. This design is performed for all rectangular columns satisfying the following conditions: - The column supports the slab at a node located within a design panel or on its boundary, - There are no beams attached to the common slabcolumn node. Table 3.6 - INTERACTIVE SLAB DESIGN PARAMETERS Parameter Name Fc Default Value Description 4.
Section 3 the denser the grid of elements, the more precise the results that will be obtained. The program extracts and processes the internal forces from the FEA results in three ways (for each load case / combination): a. For all rectangular panels, where design is performed for the entire area of the panel (four column strips, two middle strips), notional boundaries are generated that reflect each of the six design strips.
American Concrete Design 3-32 Section 3 There are two categories of output for bending moments (envelopes are reported) and flexural reinforcing in the Slab Design Report window. a. Moment Diagram page allows to browse the results displayed for each of the transverse sections of the strip or user defined section. The force shown is as previously calculated (maximum or average) and the reported required reinforcing is based on that force. b.
Section 3 3-33 Distance from extreme compression fiber to centroid of tension reinforcement, d, is assumed to be equal to: • • for longitudinal bending: slab depth - concrete cover - ½ dia. of min. size bar for transverse bending: slab depth - concrete cover - 1½ dia. of min. size bar Strength reduction factor is established in accordance with Section 9.3.2. The program allows the designer, as an option, to use the WoodArmer equations for reinforcement calculations, as follows: a.
American Concrete Design 3-34 Section 3 If both Mx1 and My1 are positive, Mxd = 0 and Myd = 0. If both Mx1 and My1 are negative, Mxd = Mx1 and Myd = My1. If Mx1 is negative and My1 positive, Mxd = Mx2 and Myd = 0. If My1 is negative and Mx1 positive, Mxd = 0 and Myd = My2. Mxd and Myd are then used in lieu of Mx and My for calculations of the required reinforcing. Punching shear design notes: • • • • Design for two-way shear is carried out in accordance with Section 11.12.
Section 3 3.8.4 Design of I-shaped beams per ACI-318 I-shaped sections can be designed as beams per the ACI 318 code. The property for these sections must be defined through a user table, I-section, or using the tapered specification. Information on assigning properties in this manner is available in sections 5.19 (Isection type) and 5.20.3 (Tapered I shape) of the Technical Reference manual.
American Concrete Design 3-36 Section 3 • If the thickness of the web is the same as the width of one of the flanges but not the other, the member is designed as a T-section or a rectangular section, depending on which side the compression due to bending is at.
Section 3 An example for I-beam design is shown below. STAAD PLANE I BEAM CONCRETE DESIGN PER ACI-318 UNIT FEET KIP JOINT COORDINATES 1 0 0 0; 2 10 0 0 MEMBER INCIDENCES 112 UNIT INCHES KIP MEMBER PROPERTY 1 TAPERED 18 10 18 15 2.5 CONSTANTS E 3300 ALL DENSITY CONCRETE ALL POISSON CONCRETE ALL SUPPORTS 1 2 PINNED UNIT FEET KIP LOAD 1 DEAD LOAD MEMBER LOAD 1 UNI GY -5.76 LOAD 2 LIVE LOAD MEMBER LOAD 1 UNI GY -7.04 LOAD COMB 3 ACI 318-02 1 1.4 2 1.
American Concrete Design 3-38 Section 3 START CONCRETE DESIGN CODE ACI 2002 UNIT INCHES KIP MINMAIN 9 ALL FC 4 ALL FYMAIN 60 ALL TRACK 2.
4-1 Timber Design Section 4 4.1 Timber Design STAAD.Pro supports timber design per two codes – 1985 AITC code and 1994 AITC code. The implementation of both the codes is explained below. 1994 AITC code implementation The salient aspects of design in accordance with the 4 th edition (1994) of the Timber Construction Manual published by the American Institute of Timber Construction are: 1.
Timber Design 4-2 Section 4 an E of 1900 ksi and an allowable bending stress, F b , of 1450 psi. A 5x5 Douglas Fir-Larch, Select Structural, Beam or Stringer member has an E of 1600 ksi and an allowable bending stress, F b , of 1600 psi. And a 5x5 Douglas Fir-Larch, Select Structural, Post or Timbers member has an E of 1600 ksi and an allowable bending stress, F b , of 1750 psi.
Section 4 Naming convention in STAAD.Pro for Dimensional Lumber sections As can be seen from Tables 8.3 through 8.6 of the AITC 1994 manual, one or more of the following attributes have to be considered while choosing a section : • • • • • Species Commercial Grade Size classification Nominal size of the section Grading rules agency STAAD uses a naming convention that incorporates all of the above. Shown below is the name of a section that has characteristics as shown.
Timber Design 4-4 Section 4 3/4” x 30” 24F-V8 DF/DF beam both have an E of 1600 ksi and an allowable bending stress in the tension zone, F bx , of 2400 psi. Therefore, in STAAD’s glulam database, the section sizes are not linked to the glulam type. Users may specify any cross-section size they choose and pick the desired glulam type. The Modulus of Elasticity and allowable stresses associated with that glulam are assigned to the member.
Section 4 Example for Dimensional Timber: UNIT FEET KIP DEFINE MATERIAL START ISOTROPIC DFLN_SS_4X4 E 273600 POISSON 0.15 DENSITY 0.025 ALPHA 5.5e-006 END DEFINE MATERIAL MEMBER PROPERTY AITC 3 4 7 8 TABLE ST DFLN_SS_4X4 CONSTANTS MATERIAL DFLN_SS_4X4 MEMB 3 4 7 8 Example for Glulam Timber: UNIT FEET KIP DEFINE MATERIAL START ISOTROPIC GLT-24F-V8_WET_DF/DF E 191923 POISSON 0.15 DENSITY 0.025 ALPHA 5.5e-006 END DEFINE MATERIAL MEMBER PROPERTY AITC 8 PRIS YD 1.5 ZD 0.
Timber Design 4-6 Section 4 Assigning the input Please see the Graphical User Interface manual for the procedure for assigning the properties, glulam types and material constants. Design parameters The timber design parameters for the AITC 4 th Edition are listed below. Table 4.1 - AITC 1994 Timber Design Parameters Name Default name used in value and referred STAAD Parameter units if Description applicable to in AITC 1994 code document Cb CB 1.0 Bearing Area Factor, Table 4.13 CF CFB 1.
Section 4 Table 4.1 - AITC 1994 Timber Design Parameters Name Default name used in value and referred STAAD units if Parameter applicable to in Description AITC 1994 code document Cr CR CSF 1.0 1.0 Repetitive Member Factor, see Section 4.5.10 CF Ct CTM 1.0 Temperature Factor, see Table 4.11 CT CTT 1.0 Buckling Stiffness Factor, see Section 4.5.15 Kb KB 1.0 Buckling Length Coefficient to calculate Kbd KBD 1.0 KbE KBE 0.609 KCE 1.0 K ey KEY 1.
Timber Design 4-8 Section 4 Table 4.1 - AITC 1994 Timber Design Parameters Name Default name used in value and referred STAAD units if Parameter applicable to in Description AITC 1994 code document SRC SRC 1.0 Slenderness ratio of Compression member SRT SRT 1.0 Slenderness ratio of Tension member RATIO 1.0 Permissible ratio of actual to allowable stress BEAM 1.0 0 = Design for end forces or locations specified by section command.
Section 4 Example for Dimensional lumber: STAAD PLANE EXAMPLE FOR DIMENSIONAL LUMBER UNIT FEET POUND JOINT COORDINATES 1 0 0 0; 2 6 0 0; 3 12 0 0; 4 18 0 0; 5 24 0 0; 6 6 3 0; 7 12 6 0; 8 18 3 0; MEMBER INCIDENCES 1 1 2; 2 2 3; 3 3 4; 4 4 5; 5 1 6; 6 6 7; 7 7 8; 8 8 5; 9 2 6; 10 3 7; 11 4 8; 12 6 3; 13 3 8; UNIT FEET POUND DEFINE MATERIAL START ISOTROPIC DFLR_SS_2X4 E 2.736e+008 POISSON 0.15 DENSITY 25 ALPHA 5.5e-006 ISOTROPIC DFLR_SS_3X6 E 2.736e+008 POISSON 0.15 DENSITY 25 ALPHA 5.
Timber Design 4-10 Section 4 7 START MP 0.99 SUPPORTS 1 PINNED 5 FIXED BUT FX MZ UNIT FEET POUND LOAD 1 DEAD+LIVE LOAD SELFWEIGHT Y -1 MEMBER LOAD 1 TO 4 UNI GY -30 5 TO 8 UNI GY -40 LOAD 2 SNOW LOAD MEMBER LOAD 5 TO 8 UNI GY -50 LOAD 3 WIND LOAD MEMBER LOAD 5 6 UNI Y -30 7 8 UNI Y 25 LOAD COMB 11 D+L+SNOW 1 1.0 2 1.0 LOAD COMB 12 D+L+SNOW+WIND 1 1.0 2 1.0 3 1.0 PERFORM ANALYSIS PRINT STATICS CHECK PARAMETER CODE AITC BEAM 1.
Section 4 Example for Glulaminated lumber: STAAD PLANE EXAMPLE FOR GLULAM DESIGN INPUT WIDTH 79 UNIT FEET KIP JOINT COORDINATES 1 0 0 0; 2 12 0 0; 3 24 0 0; 4 36 0 0; 5 0 12 0; 6 6 10 0; 7 18 6 0; 8 30 2 0; MEMBER INCIDENCES 1 1 2; 2 2 3; 3 3 4; 4 5 6; 5 6 7; 6 7 8; 7 8 4; 8 1 5; 9 2 6; 10 3 7; 11 1 6; 12 2 7; 13 3 8; UNIT INCHES KIP DEFINE MATERIAL START ISOTROPIC GLT-24F-V8_DF/DF E 1600 POISSON 0.15 DENSITY 1.44676e-005 ALPHA 5.5e-006 END DEFINE MATERIAL MEMBER PROPERTY 1 TO 7 PRIS YD 16.5 ZD 10.
Timber Design 4-12 Section 4 MEMBER LOAD 1 TO 3 UNI GY -100 4 TO 7 UNI GY -100 LOAD COMB 3 1 1.0 2 1.0 PERFORM ANALYSIS PRINT STATICS CHECK PARAMETER CODE AITC CMT 1 ALL RATIO 0.9 ALL CHECK CODE ALL FINISH 1985 AITC code implementation STAAD’s Timber design module per the 1985 AITC code (Timber Construction Manual, 3rd. Edition, 1985) allows design of Glulam timber sections.
Section 4 iii) Form Factor iv) Lateral stability of Beams and Columns v) Moisture Content Factor vi) Temperature and Curvature factors. The allowable stresses for bending, tension, compression, shear and Moduli of elasticities are modified accordingly . 5. Determines slenderness for beams and columns (Short, intermediate and long) and checks for min. eccentricity, lateral stability, buckling, bending and compression, bending and tension and horizontal shear against both axes. 6.
Timber Design 4-14 Section 4 FVZ, FVY Allowable horizontal shear stresses. VZ, VY Shear in local Z and local Y direction. ZD, YD Depth of section in local Z and Y axis. EZ, EY Minimum eccentricity along Z and Y axis. CFZ, CFY CFZ and CFY are values of the size factors in the Zaxis and Y-axis respectively. CLZ, CLY CLZ and CLY represent the factors of lateral stability for beams about Z-axis and Y-axis respectively. RATIO Permissible ratio of the stresses as provided by the user.
Section 4 b) When CF >= 1.00, the effect of CF and CL are cumulative FBZ is taken as FBZ x CFZ x CLZ FBY is taken as FBY x CFY x CLY Min. Eccentricity: The program checks against min. eccentricity in following cases: a) The member is a FRAME member and not a truss member and under compression. b) The value of actual axial compressive stress does not exceed 30% of the allowable compressive stress. c) The actual moments about both axes are less than moments that would be caused due to min. eccentricity.
Timber Design 4-16 Section 4 4.3 Input Specification A typical set of input commands for STAAD TIMBER DESIGN is listed below: UNIT KIP INCH PARAMETER CODE TIMBER GLULAM 1:16F-V3-DF/DF MEMB 1 TO 14 GLULAM 1:24F-V5-SP/SP MEMB 15 TO 31 GLULAM 20F-V1-DF/WW MEMB 32 TO 41 LAMIN 1.375 LY 168.0 MEMB 5 9 15 TO 31 LZ 176.0 MEMB 1 TO 4 6 7 8 10 TO 14 LUZ 322.6 ALL LUY 322.6 ALL WET 1.0 ALL CDT 1.33 NSF 0.85 BEAM 1.
Section 4 Glued Laminated Timber. The structural members are to be specified in the following manner: Table - 1 Members : Combination Symbol Table No. Species (Outer/core Lamination) GLULAM 1 : 16F-V3-DF/DF Table - 2 Members : Table No. Combination No. Species GLULAM 2 : 3 - DF Figure 4.2 For TABLE-2 members, the applicable stress values are selected based on the depth and the number of laminations.
Timber Design 4-18 Section 4 4.5 Orientation of Lamination Laminations are always assumed to lie along the local Z-plane of the member. The user may please note that in the MEMBER PROPERTIES section, YD always represents the depth of the section across the grain and ZD represents the width along the grain. This is in accordance with the sign convention conforming to “SET Y UP”. Y Z YD Z Y ZD YD ZD Figure 4.3 4.6 Member Selection The SELECT MEMBER command starts with the min.
Section 4 Table 4.2 - AITC 1985 Timber Design Parameters Parameter Name LZ Default Value LY LUZ Length of the Member(L) -DO1.92*L LUY 1.92*L WET 0.0 NSF 1.0 CDT CSF CTM CCR RATIO 1.0 1.0 1.0 1.0 1.0 LAMINATION BEAM 1.50 inch 1.0 Description Effective length of the column in z-axis. Same as above in y-axis. Unsupported effective length for beam in z. Unsupported effective length for beam in y. 0.0 - dry condition 1.
Timber Design 4-20 Section 4 SAMPLE OUTPUT RESULTS STAAD CODE CHECKING - (AITC) *********************** ALL UNITS ARE - KIP MEMBER FEET (UNLESS OTHERWISE NOTED) TABLE RESULT/ CRITICAL COND/ RATIO/ LOADING/ FX MY MZ LOCATION ======================================================================= 2 PR 8.000X15.000 FAIL TCM:CL. 5-18 1.205 2 2.24 C 0.00 45.38 0.0000 |--------------------------------------------------------------------------| | MEMB2 GLULAM GRADE:16F-V1-DF/WW LAM.=1.
Section 4 Output Results and Parameters Explained For CODE CHECKING and/or MEMBER SELECTION the output results are printed as shown in the previous section. The items are explained as follows: a) MEMBER refers to the member number for which the design is performed. b) TABLE refers to the size of the PRISMATIC section (B X D or ZD X YD). c) RESULT prints whether the member has PASSed or FAILed . d) CRITICAL COND refers to the CLAUSE or FORMULA NO. from the TIMBER CONSTRUCTION MANUAL (3rd.
Timber Design 4-22 Section 4 h) LOCATION specifies the actual distance from the start of the member to the section where design forces govern in case BEAM command or SECTION command is specified. OUTPUT parameters that appear within the box are explained as follows: a) MEMB refers to the same member number for which the design is performed. b) GLULAM GRADE refers to the grade of the timber. c) LAM refers to lamination thickness provided in the input or assumed by the program.
5-1 STAAD Commands and Input Instructions Section This section of the manual describes in detail various commands and related instructions for STAAD. The user utilizes a command language format to communicate instructions to the program. Each of these commands either supplies some data to the program or instructs it to perform some calculations using the data already specified. The command language format and conventions are described in Section 5.1.
STAAD Commands and Input Instructions 5-2 Section 5 Input Instructions 5.1 Command Language Conventions This section describes the command language used in STAAD. First, the various elements of the language are discussed and then the command format is described in detail.
Section 5 5.1.1 Elements of The Commands a) Integer Numbers: Integer numbers are whole numbers written without a decimal point. These numbers are designated as i 1 , i 2 , etc., and should not contain any decimal point. Negative signs (-) are permitted in front of these numbers. Omit the sign for positive. No spaces between the sign and the number. b) Floating Point Numbers: These are real numbers which may contain a decimal portion. These numbers are designated as f 1 , f 2 ... etc..
STAAD Commands and Input Instructions 5-4 Section 5 d) Repetitive Data: Repetitive numerical data may be provided in some (but not all) input tables such as joint coordinates by using the following format: n*f where n = number of times data has to be repeated f = numeric data, integer and floating point Example JOINT COORDINATES 1 3*0. This joint coordinate specification is same as: 1 0. 0. 0.
Section 5 5.1.2 Command Formats a) Free-Format Input: All input to STAAD is in free-format style. Input data items should be separated by blank spaces (not commas) from the other input data items. Quotation marks are never needed to separate any alphabetic words such as data, commands or titles. Limit a data item to 24 characters. b) Commenting Input: For documentation of a STAAD data file, the facility to provide comments is available.
STAAD Commands and Input Instructions 5-6 Section 5 Example ⎧ XY ⎫ ⎨ YZ ⎬ ⎩ XZ ⎭ In the above example, the user must make a choice of XY or YZ or XZ. Example * ⎧ FX ⎫ ⎨ FY ⎬ ⎩ FZ ⎭ Here the user can choose one or all of the listing (FX, FY and FZ) in any order. Parentheses, ( ), enclosing a portion of a command indicate that the enclosed portion is optional. The presence or absence of this portion affects the meaning of the command, as is explained in the description of the particular command.
Section 5 One restriction is that a semicolon can not separate consecutive commands. They must appear on separate lines. Example MEMBER INCIDENCES 1 1 2; 2 2 3; 3 3 4 etc. Possible Error: PRINT FORCES; PRINT STRESSES In the above case, only the PRINT FORCES command is processed and the PRINT STRESSES command is ignored. f) Listing Data: In some STAAD command descriptions, the word "list" is used to identify a list of joints, members/elements or loading cases.
STAAD Commands and Input Instructions 5-8 Section 5 parallel to the global direction specified. Note that this is not applicable to JOINTs or ELEMENTs. ALL, BEAM, PLATE, SOLID. Do not use these unless the documentation for a command specifically mentions them as available for that command. ALL means all members and elements, BEAM means all members, etc.
Section 5 General format: ⎧XRANGE ⎫ ⎨YRANGE ⎬ ⎩ZRANGE ⎭ f 1, f 2 where, XRANGE, YRANGE, ZRANGE = direction of range (parallel to global X, Y, Z directions respectively) f1, f2 = values (in current unit system) that defines the specified range. Notes 1) Only one range direction (XRANGE, YRANGE etc.) is allowed per list. (Exceptions: Area/Floor load and Master/Slave). 2) No other items may be in the list. 3) The values defining the range (f1, f2) must be in the current unit system.
STAAD Commands and Input Instructions 5-10 Section 5 STAAD Commands 5.2 Problem Initiation And Title Purpose This command initiates the STAAD run, allows the user to specify the type of the structure and an optional title. General format: STAAD ⎧PLANE ⎪SPACE ⎨ ⎪TRUSS ⎩FLOOR ⎫ ⎪ ⎬ ⎪ ⎭ (any title a 1 ) Description Any STAAD input has to start with the word STAAD. Following type specifications are available: See Section 1.
Section 5 Notes 1) The user should be careful about choosing the type of the structure. The choice is dependent on the various degrees of freedom that need to be considered in the analysis. The following figure illustrates the degrees of freedoms considered in the various type specifications. Detailed discussions are available in Section 1.3. PLANE indicates the XY plane for Y up and the XZ plane for Z up. FLOOR indicates the XZ floor for Y up and the XY floor for Z up.
STAAD Commands and Input Instructions 5-12 Section 5 5.3 Unit Specification Purpose This command allows the user to specify or change length and force units for input and output. General format: * ⎧length-unit ⎫ UNIT ⎨ ⎬ ⎩force-unit ⎭ length-unit = force-unit = ⎧INCHES ⎪FEET or FT or FO ⎪CM ⎨METER ⎪MMS ⎪DME ⎩KM ⎫ ⎪ ⎪ ⎬ ⎪ ⎪ ⎭ ⎧KIP ⎫ ⎪POUND ⎪ ⎪KG ⎪ ⎨MTON ⎬ ⎪NEWTON ⎪ ⎪KNS ⎪ ⎪MNS ⎪ ⎩DNS ⎭ Note: DME denotes Decimeters.
Section 5 specification preceding that data. Also, the input unit for angles is always degrees. However, the output unit for joint rotations (in joint displacement) is radians. For all output, the units are clearly specified by the program. Example UNIT UNIT UNIT UNIT KIP FT INCH METER KNS CM MTON Notes This command may be used as frequently as needed to specify data or generate output in the desired length and/or force units. Mixing of different unit systems (Imperial, Metric, SI etc.) is allowed.
STAAD Commands and Input Instructions 5-14 Section 5 5.4 Input/Output Width Specification Purpose These commands may be used to specify the width(s) of the lines of output file(s). General format: ⎧INPUT ⎫ ⎨ ⎬ ⎩OUTPUT ⎭ WIDTH i1 For OUTPUT WIDTH, i 1 = 72 or 118 depending on narrow or wide output. Description The user may specify the required input/output width, as required, using this command. For INPUT width, 79 is always used.
Section 5 5.5 Set Command Specification Purpose This command allows the user to set various general specifications for the analysis/design run. General format: SET ⎧ NL ⎪ DISPLACEMENT ⎪ SDAMP ⎪ WARP ⎪ ITERLIM ⎪ PRINT ⎪ SHEAR ⎪ ⎨ ⎧ON ⎫ ⎪ECHO ⎨ ⎬ ⎪ ⎩OFF ⎭ ⎪ GUI ⎩Z ⎫ ⎪ ⎪ ⎪ ⎪ ⎪ ⎪ ⎪ ⎬ ⎪ ⎪ i6 ⎪ UP ⎭ i1 i2 i3 i4 i5 i7 where, i 1 = Maximum number of primary load cases (NL) i 2 = Maximum allowable displacement tolerance for any joint in the structure.
STAAD Commands and Input Instructions 5-16 Section 5 Description See Sections 5.18 and 5.38 The SET NL command is used in a multiple analysis run if the user wants to add more primary load cases after one analysis has been performed. Specifically, for those examples, which use the CHANGE or RESTORE command, if the user wants to add more primary load cases, the NL value should be set to the maximum number with the SET NL command.
Section 5 Notes for SET Z UP The SET Z UP Command directly influences the values of the following input: 1) JOINT COORDINATE 2) Input for the PERFORM ROTATION Command 3) BETA ANGLE The following features of STAAD cannot be used with the SET Z UP command: 1. Area Load/Floor Load/Oneway Load Generation 2.
STAAD Commands and Input Instructions 5-18 Section 5 The SET PRINT 1 command is for eliminating the Zero Stiffness messages. The SET SHEAR command is for omitting the additional pure shear distortion stiffness terms in forming beam member stiffnesses. With this command you can exactly match simple textbook beam theory results.
Section 5 5.6 Separator Command Purpose This command may be used to specify the desired separator character that can be used to separate multiple lines of data on a single line of input. General format: SEPARATOR a1 Description See Section 5.1.2 The semicolon (;) is the default character which functions as the separator for multiple line data on one line. However, this separator character can be changed by the SEPARATOR command to any character a 1 , other than the comma or asterisk.
STAAD Commands and Input Instructions 5-20 Section 5 5.7 Page New Command Purpose This command may be used to instruct the program to start a new page of output. General format: PAGE NEW Description With this command, a new page of output can be started. This command provides the flexibility, the user needs, to design the output format. Notes The presentation quality of the output document may be improved by using this command properly.
Section 5 5.8 Page Length/Eject Command Purpose These commands may be used to specify the page length of the output and the desired page eject character. General format: PAGE ⎧LENGTH ⎨ ⎩EJECT ⎫ ⎬ a1 ⎭ i The page length in STAAD output is based on a default value of 60 lines . However, the user may change the page length to any number i (number of lines per page) desired. Description Standard page eject character (CNTRL L for PCs and 1 for Mini/Mfrm) is embedded in the STAAD program.
STAAD Commands and Input Instructions 5-22 Section 5 5.9 Ignore Specifications Purpose This command allows the user to provide member lists in a convenient way without triggering error messages pertaining to non-existent member numbers. General format: IGNORE LIST Description IGNORE LIST may be used if the user wants the program to ignore any nonexistent member that may be included in a member list specification.
Section 5 5.10 No Design Specification Purpose This command allows the user to declare that no design operations will be performed during the run. The memory reserved for design will be released to accommodate larger analysis jobs. General format: INPUT NODESIGN Description STAAD always assumes that at some point in the input, the user may wish to perform design for steel or concrete members. These design processes require more computer memory.
STAAD Commands and Input Instructions 5-24 Section 5 5.11 Joint Coordinates Specification Purpose These commands allow the user to specify and generate the coordinates of the JOINTs of the structure. The JOINT COORDINATES command initiates the specification of the coordinates. The REPEAT and REPEAT ALL commands allow easy generation of coordinates using repetitive patterns.
Section 5 JTORIG causes the program to use a different origin than (0, 0, 0) for all of the joints entered with this JOINT COORDINATES command. It is useful in instances such as when the center of cylinder is not at (0, 0, 0) but at a different point in space. The JTORIG command should be entered on a separate command line. Basically after the joint coordinates are entered or generated, then the xOrigin, yOrigin, and zOrigin values are added to the coordinates.
STAAD Commands and Input Instructions 5-26 Section 5 * i1 = The joint number for which the coordinates are provided. Any integer number within the limit (see section 5.2 for limit) is permitted. x 1 , y 1 and z 1 = X, Y & Z (R, θ & Z for cylindrical or R, Y & θ for cylindrical reverse) coordinates of the joint. For PLANE analyses z 1 is an optional data item when defining input for individual joints. z 1 is always required for joint generation. The following are used only if joints are to be generated.
Section 5 spaced from 3 to 6. Hence, joint 4 will have coordinates of 20.25 0.0 8.5 and joint 5 will have coordinates of 35.25 0.0 8.5. Example 2 JOINT COORDINATES 1 0.0 0.0 0.0 4 45 0.0 0.0 REPEAT 4 0.0 0.0 15.0 REPEAT ALL 10 0.0 10.0 0.0 Here, the 220 joint coordinates of a ten story 3 X 4-bay structure are generated. The REPEAT command repeats the first input line 4 times, incrementing each Z coordinate by 15. Thus, the first 2 lines are sufficient to create a "floor" of twenty joints. 1 0. 0. 0.
STAAD Commands and Input Instructions 5-28 Section 5 The following examples illustrate various uses of the REPEAT command. REPEAT 10 5. 10. 5. The above REPEAT command will repeat the last input line 10 times using the same set of increments (i.e. x = 5., y = 10., z = 5.) REPEAT 3 2. 10. 5. 3. 15. 3. 5. 20. 3. The above REPEAT command will repeat the last input line three times. Each repeat operation will use a different increment set. REPEAT 10 0. 12. 0. 15*0 0. 10. 0.
Section 5 5.12 Member Incidences Specification Purpose This set of commands is used to specify MEMBERs by defining connectivity between JOINTs. REPEAT and REPEAT ALL commands are available to facilitate generation of repetitive patterns. The member/element incidences must be defined such that the model developed represents one single structure only, not two or more separate structures. STAAD is capable of detecting multiple structures automatically.
STAAD Commands and Input Instructions 5-30 Section 5 Note: Use “REPEAT ALL 0”, to start a set of members that will be repeated if you don’t want to repeat back to the last REPEAT ALL. The following data are used for member generation only: i 4 = Second member number to which members will be generated. i 5 = Member number increment for generation. i 6 = Joint number increment which will be added to the incident joints. (i 5 and i 6 will default to 1 if left out.
Section 5 5-31 This example creates the 510 members of a ten story 3 X 4-bay structure (this is a continuation of the example started in Section 5.12). The first input line creates the twenty columns of the first floor: 1 1 21 ; 2 2 22 ; 3 3 23 ; ... ; 19 19 39 ; 20 20 40 The two commands (21 21 22 23 and REPEAT 4 3 4) create 15 members which are the second floor "floor" beams running, for example, in the east-west direction: 21 21 22; 22 22 23; 23 23 24 24 25 26; 25 26 27; 26 27 28 ... ... ...
STAAD Commands and Input Instructions 5-32 Section 5 Notes The PRINT MEMBER INFO command may be used to verify the member incidences provided or generated by REPEAT and REPEAT ALL commands. Also, use the Post Processing facility to verify geometry graphically.
Section 5 5.13 Elements and Surfaces This section describes the commands used to specify: a. Plate and Shell elements (see section 5.13.1). b. Solid elements (see section 5.13.2). c. Surface entities (see section 5.13.3).
STAAD Commands and Input Instructions 5-34 Section 5 5.13.1 Plate and Shell Element Incidence Specification Purpose This set of commands is used to specify ELEMENTs by defining the connectivity between JOINTs. REPEAT and REPEAT ALL commands are available to facilitate generation of repetitive patterns. The element incidences must be defined such that the model developed represents one single structure only, not two or more separate structures.
Section 5 i1 i 2 ...i 5 = Element number (any number up to six digits). If MEMBER INCIDENCE is provided, this number must not coincide with any MEMBER number. = Clockwise or counterclockwise joint numbers which represent the element connectivity. i 5 is not needed for triangular (3 noded) elements. The following data is needed if elements are to be generated: i 6 = Last element number to which elements are generated. i 7 = Element number increment by which elements are generated.
STAAD Commands and Input Instructions 5-36 Section 5 5.13.2 Solid Element Incidences Specification Purpose 4 through 8 noded elements, also known as solid elements, are described using the commands described below. Technical information on these elements is available in section 1.6.2 of this manual. General format The element incidences for solid elements are to be identified using the expression SOLID to distinguish them from PLATE/SHELL elements.
Section 5 Specify the four nodes of any of the faces of the solid element in a counter-clockwise direction as viewed from the outside of the element and then go to the opposite face and specify the four nodes of that face in the same direction used in specifying the nodes of the first face. The opposite face must be behind the first face, as defined by the right hand rule, i.e. the opposite (back) face points to the first (front) face, which points to the viewer.
STAAD Commands and Input Instructions 5-38 Section 5 5.13.3 Surface Entities Specification Purpose In order to facilitate rapid modeling of complex walls and slabs, a type of entity called Surface is available. At the modeling level, it corresponds to the entire structural part, such as a wall, floor slab or bridge deck. At the analysis level, it is first decomposed into a number of quadrilateral plate elements.
Section 5 General Format: SET DIVISION m SURFACE INCIDENCE n1, ..., ni SURFACE s DIVISION sd1, ..., sdj RECOPENING x1 y1 z1 x2 y2 z2 x3 y3 z3 x4 y4 z4 DIVISION od1, ..., odk where : m - number of segments to be generated between each pair of adjacent nodes n1, ..., ni - node numbers defining the perimeter of the surface, s - surface ordinal number, sd1, ..., sdj - number of divisions for each of the nodeto-node distance on the surface perimeter, x1 y1 z1 (...
STAAD Commands and Input Instructions 5-40 Section 5 2. 3. 4. 5. surface boundaries provided the nodes are collinear on edges they belong to. In addition, the user specifies the number of edge divisions that will be the basis for mesh generation. A single command per wall is used for this purpose. The program will subdivide all edges into the requested number of fragments and each of these fragments will become an edge of a plate element.
Section 5 SURFACE INCIDENCES command start the specifications of the elements. SUR 1 and SUR 2 commands define Surface elements No. 1 and 2 with default boundary divisions and no openings. SUR 3 command defines Surface No. 3 with non-default edge divisions and one opening. The DIV command following SUR 3 defines Surface element edge divisions. Non-default opening edge divisions are defined by the DIV command following the RECO command.
STAAD Commands and Input Instructions 5-42 Section 5 5.14 Element Mesh Generation Purpose This set of commands is used to generate finite element meshes. The procedure involves the definition of super-elements, which are subsequently divided into smaller elements. Description This is the second method for the generation of element incidences.
Section 5 General Format: DEFINE MESH A i x i yi z i ( ... A j x j yj z j ⎧ CYL ⎫ ⎨ ⎬ ⎩ RCYL ⎭ (x o ,y o ,z o )) ⎧( QUADRILATERAL) ⎫ ⎬ ⎩ TRIANGULAR ⎭ GENERATE ELEMENT ⎨ MESH A i A j ..... n 1 (n 2 ) MESH A m A n ..... n 3 (n 4 ) ..... ..... (up to 21 MESH input lines) where A i , A j = Alphabets A - Z or alphabets a - z. Maximum is 52. x i ,y i ,z i = Coordinates for boundary point A i . If CYL or RCYL is defined, above coordinates will be in cylindrical or reverse cylindrical coordinates system.
STAAD Commands and Input Instructions 5-44 Section 5 Limits There is a limit of 21 Mesh commands. Up to 33000 joints may be generated and up to 67000 elements. Total number of joints in the model after this command is completed may not exceed 100,000. Notes All coordinates are in current unit system. While using this facility the user has to keep the following points in mind: 1. All super-elements must be 4-noded or 8-noded.
Section 5 4. This command must be used after the MEMBER INCIDENCE & ELEMENT INCIDENCE section and before the MEMBER PROPERTIES & ELEMENT PROPERTIES section. The elements that are created internally are numbered sequentially with an increment of one starting from the last member/element number plus one. Similarly the additional joints created internally are numbered sequentially with an increment of one starting from the last joint number plus one.
STAAD Commands and Input Instructions 5-46 Section 5 7. Element incidences of the generated sub-elements may be obtained by providing the command 'PRINT ELEMENT INFORMATION' after the 'MESH...' command in the input file. 8. If the STAAD input file contains commands for JOINT COORDINATES, MEMBER INCIDENCES, ELEMENT INCIDENCES and MESH GENERATION, they should be specified in the following order: STAAD SPACE UNIT . . .
Section 5 G F C B H E D A Figure 5.4 STAAD SPACE TANK STRUCTURE WITH * MESH GENERATION UNIT . . . DEFINE MESH A 0 0 0 ; B 0 20 0 ; C 20 20 0 D 20 0 0 ; E 0 0 -20 ; F 0 20 -20 G 20 20 -20 ; H 20. 0. -20 GENERATE ELEMENT MESH AEHD 16 MESH EABF 16 MESH ADCB 16 MESH HEFG 16 MESH DHGC 16 Typical generated Quad and Triangular elements: Typical generated Quad elements Typical generated Triangular elements Figure 5.
STAAD Commands and Input Instructions 5-48 Section 5 5.15 Redefinition of Joint and Member Numbers Purpose This command may be used to redefine JOINT and MEMBER numbers. Original JOINT and MEMBER numbers are substituted by new numbers. General Format: SUBST ⎧ ⎪ ⎨ ⎪ ⎩ ⎧ JOINT ⎫ ⎨ ⎬ ⎩MEMBER ⎭ COLUMN ⎧XRANGE ⎫ ⎨YRANGE ⎬ ⎩ZRANGE ⎭ ⎫ ⎪ ⎬ ⎪ ⎭ f1, f2 START i where, f 1 and f 2 are two range values of x, y, or z and i is the new starting number.
Section 5 Joints with Y coordinates ranging from 9.99 to 10 meters will have a new number starting from 101. Columns will be renumbered starting with the new number 901. Note Meaningful respecification of JOINT and MEMBER numbers may significantly improve ease of interpretation of results.
STAAD Commands and Input Instructions 5-50 Section 5 5.16 Listing of entities (Members / Elements / Joints, etc.) by Specification of GROUPS This command allows the user to specify a group of entities such as joints, members, plate & solid elements and save the information using a 'group-name'. The 'group-name' may be subsequently used in the input file instead of a member/element/joint list to specify other attributes.
Section 5 END GROUP DEFINITION where, group-name = an alphanumeric name specified by the user to identify the group. The group-name must start with the '_' (underscore) character and is limited to 24 characters. member-list = the list of members/elements/solids belonging to the group. TO, BY, ALL, BEAM, PLATE, and SOLID are permitted. ALL means all members+ plates+ solids; BEAM means all beams; PLATE all plates; and SOLID all solids. joint-list = the list of joints belonging to the group.
STAAD Commands and Input Instructions 5-52 Section 5 suffice, and that is for defining panels during a FLOOR LOAD assignment. In section 5.32.4 of this manual, as explained under the topic “Applying floor load on members grouped under a FLOOR GROUP name”, a panel has to be specified using a FLOOR GROUP, not a MEMBER GROUP. A FLOOR GROUP is presently not accepted in lieu of a member-list for any other command.
Section 5 5.17 Rotation of Structure Geometry Purpose This command may be used to rotate the currently defined joint coordinates (and the attached members/elements) about the global axes. General format: PERFORM ROTATION * ⎧X ⎨Y ⎩Z d1 ⎫ d2 ⎬ d3 ⎭ where, d 1 , d 2 , d 3 are the rotations (in degrees) about the X, Y and Z global axes respectively. This command may be entered after the Joint Coordinates or between two Joint Coordinate commands or after all Member/Element Incidences are specified.
STAAD Commands and Input Instructions 5-54 Section 5 5.18 Inactive/Delete Specification Purpose This set of commands may be used to temporarily INACTIVATE or permanently DELETE specified JOINTs or MEMBERs. General format: INACTIVE ⎧ MEMBERS member-list ⎫ ⎨ ⎬ ⎩ ELEMENTS element-list ⎭ DELETE ⎧ MEMBERS member-list ⎫ ⎨ ⎬ joint-list ⎩ JOINTS ⎭ Description These commands can be used to specify that certain joints or members be deactivated or completely deleted from a structure.
Section 5 c) d) e) f) g) h) i) place. For example, such joints may have been generated for ease of input of joint coordinates and were intended to be deleted. Hence, if a DELETE MEMBER command is used, a DELETE JOINT command should not be used. The DELETE MEMBER command is applicable for deletion of members as well as elements.
STAAD Commands and Input Instructions 5-56 Section 5 5.19 User Steel Table Specification Purpose STAAD allows the user to create and use customized Steel Section Table (s) for Property specification, Code checking and Member Selection. This set of commands may be used to create the table(s) and provide necessary data. General format: START USER TABLE TABLE i 1 (f n ) section-type section-name property-spec END where, i1 = fn = section-type = table number (1 to 99).
Section 5 section-name = propertyspec = Any user designated section name, use 1 to 12 characters. First three characters of Pipes and Tubes must be PIP and TUB respectively. Only alphanumeric characters and digits are allowed for defining section names. (Blank spaces, asterisks, question marks, colon, semi-colon etc. are not permitted.) Properties for the section. The requirements are different for each section type as follows.
STAAD Commands and Input Instructions 5-58 Section 5 5) TF = Thickness of flange 6) IZ = Moment of inertia about local z-axis (usually strong axis) 7) IY = Moment of inertia about local y-axis 8) IX = Torsional constant 9) AY = Shear area in local y-axis. If zero, shear deformation is ignored in the analysis. 10) AZ = Same as above except in local z-axis. Channel 1) AX, 2) D, 3) TW, 4) WF, 5) TF, 6) IZ, 7) IY, 8) IX, 9) CZ, 10) AY, 11) AZ CZ Y Figure 5.
Section 5 Double Angle 1) D, 2) WF, 3) TF, 4) SP, 5) IZ, 6) IY, 7) IX, 8) CY, 9) AY, 10) AZ Y WF CY Z SP Figure 5.7 Tee 1) AX, 2) D, 3) WF, 4) TF, 5) TW, 6) IZ, 7) IY, 8) IX, 9) CY, 10) AY, 11) AZ Y CY Z Figure 5.
STAAD Commands and Input Instructions 5-60 Section 5 Tube 1) AX, 2 ) D, 3) WF, 4) TF, 5) IZ, 6) IY, 7) IX, 8) AY, 9) AZ General The following cross-sectional properties should be used for this section-type. This facility allows the user to specify a built-up or unconventional steel section. Provide both the Y and Z parameters for design or code checking. 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) 14) 15) 16) AX D TD = Cross section area. = Depth of the section.
Section 5 Isection This section type may be used to specify a generalized I-shaped section. The cross-sectional properties required are listed below. This facility can be utilized to specify tapered I-shapes. 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) DWW TWW DWW1 BFF TFF BFF1 TFF1 AYF AZF XIF = = = = = = = = = = Depth of section at start node. Thickness of web. Depth of section at end node. Width of top flange. Thickness of top flange. Width of bottom flange. Thickness of bottom flange.
STAAD Commands and Input Instructions 5-62 Section 5 NOTES: 1) DWW should never be less than DWW1. The user should provide the member incidences accordingly. 2) The user is allowed the following options for the values AYF, AZF and XIF. a) If positive values are provided, they are used directly by the program. b) If zero is provided, the program calculates the properties using the following formula. AYF = D x TWW (where D =Depth at section under consideration) AZF = 0.
Section 5 Example START USER TABLE TABLE 1 UNIT . . . WIDE FLANGE W14X30 8.85 13.84 .27 W21X50 14.7 20.83 .38 W14X109 32. 14.32 .525 TABLE 2 UNIT . . . ANGLES L25255 2.5 2.5 0.3125 L40404 4. 4. .25 .795 END * 6.73 .385 291. 19.6 .38 0 0 6.53 .535 984 24.9 1.14 7.92 0 14.605 .86 1240 447 7.12 7.52 0 .489 0 0 0 0 These section-names must be provided in ascending order by weight, since the member-selection process uses these tables and the iteration starts from the top.
STAAD Commands and Input Instructions 5-64 Section 5 UNIT . . . WIDE FLANGE W14X30 8.85 13.84 .27 6.73 .385 291. 19.6 .38 0 0 W21X50 14.7 20.83 .38 6.53 .535 984 24.9 1.14 7.92 0 W14X109 32. 14.32 0.525 14.605 .86 1240 447 7.12 7.52 0 and the file TFILE2 will contain: UNIT . . . ANGLES L25255 2.5 2.5 .3125 .489 0 0 L40404 4. 4. .25 .795 0 0 Notes The User-Provided Steel Table(s) may be created and maintained as separate file(s). The same files may be used for all models using sections from these tables.
Section 5 5.20 Member Property Specification Purpose This set of commands may be used for specification of section properties for frame members. The options for assigning properties come under 2 broad categories: • • Those which are specified from built-in property tables supplied with the program, such as for steel, aluminum and timber.
STAAD Commands and Input Instructions 5-66 Section 5 The MEMBER PROPERTY command may be extended to multiple lines by ending all lines but the last with a space and hyphen (-). Properties which are specified from built-in property tables 1.
Section 5 The MEMBER PROPERTY command may be extended to multiple lines by ending all lines but the last with a space and hyphen (-). 2.
STAAD Commands and Input Instructions 5-68 Section 5 4. General format for Aluminum: MEMBER PROPERTIES ALUMINUM member-list TABLE ST section-name-in-table The section on aluminum design in the International Codes manual contain information on the section types which can be assigned for the aluminum table in the above list. 5.
Section 5 5.20.1 Type Specs and Additional Specs for assigning properties from Steel Tables Purpose The following commands are used for specifying section properties from built-in steel table(s). General format: type-spec . table-name type-spec = additional-spec. ⎧ST ⎫ ⎪RA ⎪ ⎪D ⎪ ⎪LD ⎪ ⎪SD ⎪ ⎨T ⎬ ⎪CM ⎪ ⎪TC ⎪ ⎪BC ⎪ ⎩TB ⎭ ST specifies single section from the standard built-in tables. RA specifies single angle with reverse Y-Z axes (see Section 1.5.2). D specifies double channel.
STAAD Commands and Input Instructions 5-70 Section 5 also. For details on specifying sections from the American steel tables, see Section 2.2.1 of this manual. * ⎧SP ⎪WP ⎪TH ⎪WT additional-spec = ⎨DT ⎪OD ⎪ID ⎪CT ⎪FC ⎪CW ⎩CD SP f 1 = WP f 2 = TH f 3 = WT f 4 DT f 5 OD f 6 = = = ID f 7 CT f 8 FC f 9 = = = CW f 10 CD f 11 = = See Section 1.7.2 a.
Section 5 Notes All values f 1-9 must be supplied in current units. Some important points to note in the case of the composite section are: 1. The 'CM' parameter can be assigned to I-shaped sections only. A 'CM' (composite) section is one obtained by considering a portion of a concrete slab to act in unison with the I shaped steel section. FC is the strength or grade of concrete used in the slab. In the USA, FC is called the specified compressive strength of concrete. Typical values of FC range between 2.
STAAD Commands and Input Instructions 5-72 Section 5 Not all I shaped sections have a corresponding T. This may be inferred by going through the section libraries of individual countries and organizations. In such cases, if a user were to specify such a T section, the program will terminate with the message that the section does not exist. 5. Steel Cover plates also can be added only to I shaped sections. Thus, the 'TC', 'BC' and 'TB" are not applicable to any shape other than an I shape. Figure 5.
Section 5 5-73 5.20.2 Prismatic Property Specification Purpose The following commands are used to specify section properties for prismatic cross-sections. General format: For the PRISMATIC specification, properties are provided directly (End each line but last with a hyphen “-”) as follows: * property-spec = See Section 1.7.1 AX IX IY IZ AY AZ ⎧AX ⎪IX ⎪IY ⎪IZ ⎨AY ⎪AZ ⎪YD ⎪ZD ⎪YB ⎩ZB f1 ⎫ f2 ⎪ f3 ⎪ f4 ⎪ f5 ⎬ f6 ⎪ f7 ⎪ f8 ⎪ f9 ⎪ f10 ⎭ ZD YD ZD YD YB ZB T-SECTION ZB TRAPEZOIDAL SECTION Figure 5.
STAAD Commands and Input Instructions 5-74 Section 5 YD ZD YB ZB f 7 = Depth of the member in local y direction. (Diameter of section for circular members) f 8 = Depth of the member in local z direction. If ZD is not provided and YD is provided, the section will be assumed to be circular. f 9 = Depth of stem for T-section. f 10 = Width of stem for T-section or bottom width for TRAPEZOIDAL section.
Section 5 5.20.2.1 Prismatic Tapered Tube Property Specification Purpose The following commands are used to specify section properties for prismatic tapered tube cross-sections. For the property types shown below, additional information can be obtained from Table 2.1 of the ASCE 72 document, 2nd edition. General format: ⎫ * ⎧ROUND HEXDECAGONAL ⎪ ⎪ property-spec = ⎨DODECAGONAL ⎬ START d1 END d2 THICK t ⎪ ⎪OCTAGONAL HEXAGONAL ⎪ ⎪ SQUARE ⎭ ⎩ START END THICK d 1 = Depth of section at start of member.
STAAD Commands and Input Instructions 5-76 Section 5 HEXAGONAL (6 SIDES) D t t OCTAGONAL (8 SIDES) DODECAGONAL (12 SIDES) t t D D HEXDECAGONAL (16 SIDES) ROUND D t t D Figure 5.
Section 5 5.20.3 Tapered Member Specification Purpose The following commands are used to specify section properties for tapered I-shapes. General format: argument-list = f 1 f 2 f 3 f 4 f 5 (f 6 f 7 ) See Section 1.7.4 where, f 1 = Depth of section at start node. f 2 = Thickness of web. f 3 = Depth of section at end node. f 4 = Width of top flange. f 5 = Thickness of top flange. f 6 = Width of bottom flange. Defaults to f 4 if left out. f 7 = Thickness of bottom flange.
STAAD Commands and Input Instructions 5-78 Section 5 5.20.4 Property Specification from User Provided Table Purpose The following commands are used to specify section properties from a previously created USER-PROVIDED STEEL TABLE. General format: member-list UPTABLE I1 section-name UPTABLE stands for user-provided table i 1 = table number as specified previously (1 to 99) section-name = section name as specified in the table. (Refer to Section 5.19) See Section 1.7.3 Example See Section 5.20.
Section 5 5.20.5 Assign Profile Specification Purpose The ASSIGN command may be used to instruct the program to assign a suitable steel section to a frame member based on the profile-spec shown below. General format: profile-spec = See Section 1.7.5 ⎧BEAM ⎫ ⎪COLUMN ⎪ ⎨ ⎬ ⎪CHANNEL ⎪ ⎩ANGLE (DOUBLE) ⎭ Example See Section 5.20.6 Notes Sections are always chosen from the relevant built-in steel table.
STAAD Commands and Input Instructions 5-80 Section 5 5.20.6 Examples of Member Property Specification This section illustrates the various options available for MEMBER PROPERTY specification Example UNIT . . . MEMBER PROPERTIES 1 TO 5 TABLE ST W8X31 9 10 TABLE LD L40304 SP 0.25 12 TO 15 PRISMATIC AX 10.0 IZ 1520.0 17 18 TA ST PIPE OD 2.5 ID 1.75 20 TO 25 TA ST TUBE DT 12. WT 8. TH 0.5 27 29 32 TO 40 42 PR AX 5. IZ 400. IY 33. IX 0.2 YD 9. ZD 3.
Section 5 Member 56 is a wideflange W12X26 with a 4.0 unit wide cover plate of 0.3 units of thickness at the top. Member 57 is a composite section with a concrete slab of 5.0 units of thickness at the top of a wide flange W14X34. The compressive strength of the concrete in 2 the slab is 3.0 force/length .
STAAD Commands and Input Instructions 5-82 Section 5 5.20.7 Composite Decks As explained in section 1.7.7 of this manual, a composite deck generation facility is now built into the program. The command syntax for defining the deck within the STAAD input file is as shown below.
Section 5 member-list = d1 d2 d3 = = = and is limited to 23 characters. This name must not be the same as any group name. the list of members belonging to the deck. TO, BY, ALL, and BEAM are permitted. ALL means all members in structure; BEAM means all beams. x component of the direction of the deck. y component of the direction of the deck. z component of the direction of the deck. The following parameters may be in any order or omitted. They only apply to the composite members listed above.
STAAD Commands and Input Instructions 5-84 Section 5 The following parameter may be specified by member list. They only apply to the composite members listed above. f13 = concrete width for each composite member listed. cw-member-list = the list of composite members in this deck that have this width. Enter as many CW lines as necessary to define the width of all composite members of this deck. This Deck definition data should be entered after the member properties have been entered.
Section 5 Example START DECK DEFINITION _DECK DEC-1 PERIPHERY 4 16 40 18 38 56 50 49 DIRECTION 0.000000 0.000000 -1.000000 COMPOSITE 41 7 4 38 OUTER 7 8 31 30 VENDOR USSTEEL DIA 0.700 HGT 2.75 CT 11.0 FC 3.1 RBW 2.6 RBH 0.1 CMP 1.0 SHR 1 CD 0.0000870 CW 123.000000 MEMB 41 CW 123.000000 MEMB 7 CW 61.500000 MEMB 4 CW 61.
STAAD Commands and Input Instructions 5-86 Section 5 5.20.8 Curved Member Specification Purpose The following commands are used to specify that a member is curved. The curve must be a segment of a circle and the internal angle subtended by the arc must be less than 180 degrees. Any non-tapered cross-section is permitted. General Format: MEMBER CURVED member-list RADIUS r GAMMA g PRESS p where r = radius in length units g = The angle in degrees used to define the plane of the circle.
Section 5 ASME Boiler and Pressure Vessel Code, Section III, NB3687.2, 1971, for Class I components is used to calculate the flexibility reduction factor. Set p = 0 or omit for this flexibility increase calculation to occur with internal pressure equal to zero. Set p > 0 to specify internal pressure to use in this flexibility calculation. Pressure reduces the flexibility increase. Set p = -9999 to ignore this additional flexibility calculation and use only beam theory.
STAAD Commands and Input Instructions 5-88 Section 5 Notes: 1) The input for defining the curved member involves 2 steps. The first is the member incidence, which is the same as that for a straight line member. The second is the command described above, which indicates that the segment between the 2 nodes of the member is curved, and not a straight line. 2) Any non-tapered cross section property currently available in STAAD can be assigned to these members.
Section 5 Y Y Start Node End Node Gamma = 0° Gamma = 0° Start Node End Node X Start Node X Y 5-89 Y End Node Gamma = 180° Gamma = 180° End Node Start Node X X Gamma angle for various configurations of the circular arc lying in the global XY plane Figure 5.
STAAD Commands and Input Instructions Section 5 Y Y End Node Start Node Gamma = 0° Gamma = 0° Start Node End Node X Y X Y Start Node End Node Gamma = 180° Gamma = 180° Start Node End Node X X 5-90 Gamma angle for various configurations of the circular arc lying in the global XY plane Figure 5.
Section 5 Y Y Start Node 5-91 End Node Gamma = 0° Gamma = 180° End Node Start Node Z Z Y Y Start Node End Node Gamma = 0° Gamma = 180° End Node Start Node Z Z Gamma angle for various configurations of the circular arc lying in the global YZ plane Figure 5.
STAAD Commands and Input Instructions Section 5 Y Y End Node Start Node Gamma = 0° Gamma = 0° Start Node End Node Z Y Z Y Start Node End Node Gamma = 180° Start Node Gamma = 180° End Node Z Gamma angle for various configurations of the circular arc lying in the global YZ plane Figure 5.
Section 5 X X Start Node Start Node Gamma = +90° Gamma = -90° End Node End Node Z X Z X End Node End Node Gamma = -90° Gamma = +90° Start Node Start Node Z 5-93 Z Gamma angle for various configurations of the circular arc lying in the global XZ plane Figure 5.
STAAD Commands and Input Instructions Section 5 X X Start Node End Node Gamma = +90° Gamma = -90° Start Node End Node Z Z X X 5-94 End Node Start Node Gamma = +90° Gamma = -90° Start Node Z End Node Z Gamma angle for various configurations of the circular arc lying in the global XZ plane Figure 5.13f Member local axis system The local axis directions for curved members are dependent on the point of interest along the curve. The general rules for local axis, as laid out in Section 1.5.
Section 5 5-95 Sign convention for joint displacements The displacements of the nodes of the curved member are along the global axis system just as in the case of straight members. Sign convention for member end forces The member end forces for curved members are quite similar to that for straight members. The only distinguishing item is that they are normal and tangential to the local axis at the corresponding ends.
STAAD Commands and Input Instructions 5-96 Section 5 Example staad space unit kip feet joint coord cyl reverse 1 150 0 0 13 150 0 90 repeat 1 30 0 0 repeat all 1 0 15 0 memb inci 1 1 27 26 101 27 28 112 113 40 41 124 201 27 40 213 start group definition member _column 1 to 26 _circumferential 101 to 124 _radial 201 to 213 end group definition member properties _column pris yd 3.0 _circumferential pris yd 3.0 _radial pris yd 3.
Section 5 Notes 1. 2. The radius should be in current units. Certain attributes like releases, TENSION/COMPRESSION flags, and several member load types are currently not available. Section forces too are currently not available.
STAAD Commands and Input Instructions 5-98 Section 5 5.20.9 Applying Fireproofing on members STAAD.Pro now includes a method to automatically consider the weight of fireproofing material applied to structural steel. Two types of fireproofing configurations are currently supported. They are: Block Fireproofing (BFP): The next figure shows this configuration. The fire-protection material forms a rectangular block around the steel section.
Section 5 T T T T T T T T T BFP - BLOCK FIREPROOFING Figure 5.14 Contour Fireproofing (CFP): In this configuration, the fire-protection material forms a coating around the steel section as shown in the next figure. The area of fireproofing material (A fp ) for this case is calculated in the following manner.
STAAD Commands and Input Instructions 5-100 Section 5 B f is the flange width D the overall depth of the steel section T is the thickness of the fireproofing material beyond the outer edges of the cross section as shown in the next figure. T f is the thickness of the flange for the I shape and Tee T a is the thickness of the leg of the angle T w is the thickness of the web for the I shape and Tee A steel = Area of the steel section T T CFP - CONTOUR FIREPROOFING Figure 5.
Section 5 Command Syntax MEMBER FIREPROOFING ⎧BFP ⎫ Member-list FIRE ⎨ ⎬ THICKNESS f1 DENSITY f2 ⎩CFP⎭ where, f1 = thickness (T in the figures above) in length units f2 = density of fireproofing material in (force / length ^ 3) units In the actual load case itself, nothing besides the SELFWEIGHT command is necessary to instruct the program to include the weight of the fireproofing material in the selfweight calculation. Example Problem STAAD SPACE UNIT KIP FEET JOINT COORDINATES 1 0. 0. ; 2 0. 15. ; 3 20.
STAAD Commands and Input Instructions 5-102 Section 5 UNIT KIP FT LOADING 1 DEADWEIGHT OF STEEL + FIREPROOFING SELF Y -1.0 LOAD 2 LIVE MEMBER LOAD 2 UNI GY -0.8 LOAD COMBINATION 3 1 0.75 2 0.
Section 5 5.21 Element / Surface Property Specification General Individual plate elements, and the Surface element need to have their thickness specified before the analysis can be performed. The commands for specifying this information are explained in this section. No similar properties are required for solid elements. However, constants such as modulus of elasticity, Poisson’s Ratio, etc. are required.
STAAD Commands and Input Instructions 5-104 Section 5 5.21.1 Element Property Specification Purpose This set of commands may be used to specify properties of plate finite elements. General Format: ELEMENT PROPERTY element-list THICKNESS f 1 (f 2 , f 3 , f 4 ) = Thickness of the element. f1 f 2 ...f 4 = Thicknesses at other nodes of the element, if different from f 1 . Description See Section 1.6 Elements of uniform or linearly varying thickness may be modeled using this command.
Section 5 5.21.2 Surface Property Specification Purpose This set of commands may be used to specify properties of surface entities. General Format: SURFACE PROPERTY surface-list THICKNESS t t = Thickness of the surface element, in current units.
STAAD Commands and Input Instructions 5-106 Section 5 5.22 Member/Element Releases STAAD allows specification of releases of degrees of freedom for frame members and plate elements. Section 5.22.1 describes MEMBER release options and Section 5.22.2 describes ELEMENT release options.
Section 5 5-107 5.22.1 Member Release Specification Purpose This set of commands may be used to fully release specific degrees of freedom at the ends of frame members. They may also be used to describe a mode of attachment where the member end is connected to the joint for specific degrees of freedom through the means of springs .
STAAD Commands and Input Instructions 5-108 Section 5 For members 1, 10, 11 and 13 to 18, the moment about the local Z axis is released at their end joint. Also, the members are attached to their END joint about their local x axis through a momentspring whose stiffness is 200.0 units of force-length/Degree. Members 1 and 11 are released at both start and end joints, though not necessarily in the same degrees of freedom. Partial Moment Release Moments at the end of a member may be released partially.
Section 5 5-109 The above RELEASE command will apply a factor of 0.75 on the moment related stiffness coefficients at START of members 15 to 25. Notes Member releases are a means for describing a type of end condition for members when the default condition, namely, fully moment and force resistant, is not applicable. Examples are bolted or riveted connections.
STAAD Commands and Input Instructions 5-110 Section 5 5.22.2 Element Release Specification Purpose This set of commands may be used to release specified degrees of freedoms at the corners of plate finite elements. General Format: ELEMENT RELEASE element-list See Section 1.8 ⎧J1 ⎨J2 ⎪J3 ⎩J4 ⎫ ⎬ ⎪ ⎭ * ⎧FX ⎪FY ⎨FZ ⎪MX ⎪MY ⎩MZ ⎫ ⎪ ⎬ ⎪ ⎪ ⎭ where the keywords J1, J2, J3 and J4 signify joints in the order of the specification of the element incidence.
Section 5 5-111 Notes 1. All releases are in the local axis system. See Figure 1.13 for the various degrees of freedom. Fx and Fy have the same sense as Sx and Sy in Figure 1.13. Fz has the same sense as SQx or SQy. Generally, do not over release. The element must still behave as a plate after the releases. 2. Selfweight is applied at each of the nodes as if there were no releases. 3. Thermal stresses will include the fixed-end thermal pre-stress as if there were no release. 4.
STAAD Commands and Input Instructions 5-112 Section 5 5.22.3 Element Ignore Stiffness Purpose Structural units like glass panels or corrugated sheet roofs are subjected to loads like wind pressures or snow loads. While these units are designed to carry those loads and transmit those loads to the rest of the structure, they are not designed to provide any additional stiffness to the structure.
Section 5 5.23 Member Truss/Cable/Tension/Compression Specification A member can have only one of the following specifications: MEMBER TRUSS MEMBER TENSION MEMBER COMPRESSION MEMBER RELEASES If multiple specifications are applied to the same member, only the last entered will be used (Warnings will be printed). MEMBER TRUSS, MEMBER TENSION, MEMBER COMPRESSION, and MEMBER CABLE are axial-only for stiffness. MEMBER CABLE are special truss members that may also be specified as tension-only. Sections 5.23.
STAAD Commands and Input Instructions 5-114 Section 5 5.23.1 Member Truss Specification Purpose This command may be used to model a specified set of members as TRUSS members. Description This specification may be used to specify TRUSS type members in a PLANE, SPACE or FLOOR structure. The TRUSS members are capable of carrying only axial forces. Typically, bracing members in a PLANE or SPACE frame will be of this nature.
Section 5 Notes The TRUSS member has only one degree of freedom - the axial deformation. Note also that Member Releases are not allowed. Selfweight and transverse loads may induce shear/moment distributions in the member. Member loads are lumped at each end, whereas a frame member with moment releases only retains the axial component of the applied member load.
STAAD Commands and Input Instructions 5-116 Section 5 5.23.2 Member Cable Specification Purpose This command may be used to model a specified set of members as CABLE members. Description for use in all analyses except Non Linear Cable Analysis: The CABLE members, in addition to elastic axial deformation, are also capable of accommodating the stiffness effect of initial tension and tension due to static loads. Theoretical discussions of CABLE members are presented in Section 1.11 of this manual.
Section 5 This is a truss member but not a tension-only member unless you also include this member in a MEMBER TENSION input. See section 5.23.3. Note also that Member Releases are not allowed. The tension is a preload and will not be the final tension in the cable after the deformation due to this preload. Description for use in Non Linear Cable Analysis : The CABLE members, in addition to elastic axial deformation, are also capable of accommodating large displacements.
STAAD Commands and Input Instructions 5-118 Section 5 5.23.3 Member Tension/Compression Specification Purpose This command may be used to designate certain members as Tension-only or Compression-only members. General Format: MEMBER TENSION member - list MEMBER COMPRESSION member - list MEMBER TENSION 0 (No list required) Description Tension-only members are truss/cable members that are capable of carrying tensile forces only.
Section 5 command must be used to convey to STAAD that multiple analyses and multiple structural conditions are involved. For NON-LINEAR CABLE ANALYSIS : This command is unnecessary and ignored. Cables are automatically assumed to be partially to fully tension only (except that there should always be selfweight) without this command. In this analysis type, trusses without preload are assumed to be linear members that carry both tension and compression regardless of this command.
STAAD Commands and Input Instructions 5-120 Section 5 2) A member declared as a TENSION only member or a COMPRESSION only member will carry axial forces only. It will not carry moments or shear forces. In other words, it is a truss member. 3) The MEMBER TENSION and MEMBER COMPRESSION commands should not be specified if the INACTIVE MEMBER command is specified. 4) Do not use Load Combination to combine these cases.
Section 5 … LOAD 2 … LOAD 3 … LOAD 4 … LOAD 5 REPEAT LOAD … PERFORM ANALYSIS CHANGE LOAD LIST ALL PRINT … PRINT … PARAMETER … CHECK CODE … FINISH MEMBER TENSION 0 This command switches off ALL tension/compression only specifications for load cases which are specified subsequent to this command, usually entered after a CHANGE command. There is no list associated with this command. Hence, for any further primary load cases, the tension/compression only attributed is disabled for ALL members.
STAAD Commands and Input Instructions 5-122 Section 5 convergence may not be possible using this procedure, do not set the limit too high. c) The principle used in the analysis is the following. • The program reads the list of members declared as MEMBER TENSION and/or COMPRESSION. • The analysis is performed for the entire structure and the member forces are computed.
Section 5 5.24 Element Plane Stress and Inplane Rotation Specifications Purpose These commands allow the user to model the following conditions on plate elements a) PLANE STRESS condition b) In-plane rotation stiffness reformulated to be rigid or to be zero. General Format: ELEMENT ⎧ PLANE STRESS ⎨ RIGID ( INPLANE ROTATION ) ⎩ IGNORE ( INPLANE ROTATION ) ⎫ ⎬ ⎭ element-list Description See Section 1.
STAAD Commands and Input Instructions 5-124 Section 5 element formulation normally includes this important action automatically. However, it may be noted that some element formulations ignore this action by default. The user may utilize this option to compare STAAD results with solutions from these programs. These options are exclusive of each other and also exclusive of element releases. No single element may have more than one of these options.
Section 5 5-125 5.25 Member Offset Specification Purpose This command may be used to rigidly offset a frame member end from a joint to model the offset conditions existing at the ends of frame members.
STAAD Commands and Input Instructions 5-126 Section 5 wp in the diagram refers to the location of the centroid of the starting or ending point of the member. LOCAL is an optional parameter, if not entered then f1, f2, f3 are assumed to be in global. LOCAL means that the distances f1, f2, f3 are in the same member coordinate system that would result if the member were not offset and BETA = 0.0. Example MEMBER OFFSET 1 START 7.0 1 END -6.0 0.0 2 END -6.0 -9.
Section 5 5-127 5.26 Specifying and Assigning Material Constants Purpose Material constants are attributes like Modulus of Elasticity and Density which are required for operations like generating the stiffness matrix, computing selfweight, and for steel and concrete design. In STAAD, there are 2 ways in which this data may be specified : a. a 2-step process that involves step 1 - Creating the material data by defining MATERIAL tags specified under the heading DEFINE MATERIAL (see Section 5.26.
STAAD Commands and Input Instructions 5-128 Section 5 b. Assign material attributes explicitly by specifying the individual constants as explained in section 5.26.2. CONSTANTS E ... POISSON .. Section 5.26.3 explains the commands required to assign material data to Surface elements.
Section 5 5.26.1 The Define Material Command Purpose This command may be used to specify the material properties by material name. Then assign the members and elements to this material name in the CONSTANTS command.
STAAD Commands and Input Instructions 5-130 Section 5 plates or when Poisson cannot be computed from G. DENSITY specifies weight density. ALPHA Co-efficient of thermal expansion. DAMPING or CDAMP Damping ratio to be used in computing the modal damping by the composite damping method. Value of the corresponding constants. For E, G, f1 f2 POISSON, DENSITY, ALPHA and damping. For plates only, the first value is for local x direction and the second for local y.
Section 5 5.26.2 Specifying CONSTANTS for members, plate elements and solid elements Purpose This command may be used to specify the material properties (Moduli of Elasticity and Shear, Poisson's ratio, Density, Coefficient of linear expansion, and material damping) of the members and elements. In addition, this command may also be used to specify the member orientation (BETA angle or REFERENCE point).
STAAD Commands and Input Instructions 5-132 Section 5 E G specifies Young's Modulus. This value must be provided before the POISSON for each member/element in the Constants list. specifies Shear Modulus. Enter only for beams & plates and when Poisson would not be 0.01 to 0.499. POISSON specifies Poisson's Ratio. If G is not entered, then this value is used for calculating the Shear Modulus (G=0.5xE/(1+POISSON)). Must be 0.01 to 0.499. Poisson must be entered when Poisson cannot be computed from G.
Section 5 next page.] The 'RANGLE' option rotates the section through an angle equal to (180 - "alpha"). Both options will work the same way for equal angles. For unequal angles, the right option must be used based on the required orientation.
STAAD Commands and Input Instructions 5-134 Section 5 Local Y Global X α α Local Z as well as Global Z Orientation of a column ( vertical member ) corresponding to BETA = 0; Local X and Global Y come out of the paper ( Local X is parallel to Global Y ) Global X α Local Y Global Z Local Z Orientation of a column ( vertical member ) corresponding to BETA = ANGLE Local X and Global Y come out of the paper ( Local X is parallel to Global Y ) Figure 5.
Section 5 Value of the corresponding constants. For E, G, POISSON, DENSITY, ALPHA and CDAMP, builtin material names can be entered instead of f 1 . The built-in names are STEEL, CONCRETE & ALUMINUM. Appropriate values will be automatically assigned for the built-in names. f1 CONSTANTS in Kip, inch, Fahrenheit units Constant E (US) Poisson’s Density Alpha CDAMP Steel 29000 Concrete 3150 Aluminum 10000 Units Kip/in 2 0.30 .17 .33 .000283 .0000868 .000098 Kip/in 3 6.5E-6 5.5E-6 12.
STAAD Commands and Input Instructions 5-136 Section 5 Example DEFINE MATERIAL ISOTROPIC CFSTEEL E 28000. POISSON 0.25 DENSITY 0.3E-3 ALPHA 11.7E-6 DAMP 0.075 END MATERIAL CONSTANTS MATERIAL CFSTEEL MEMB 1 TO 5 CONSTANTS E 2.1E5 ALL BETA 45.0 MEMB 5 7 TO 18 DENSITY STEEL MEMB 14 TO 29 BETA 90 MEMB X The last command in the above example will set BETA as 90 ° for all members parallel to the X-axis. Notes 1) The value for E must always be given first in the Constants list for each member/element.
Section 5 7) If G and Poisson are both required in the analysis, such as for the stiffness matrix of plate elements, and G is specified, but Poisson is not, then, Poisson is calculated from [(E/2G) – 1]. 8) To obtain a report of the values of these terms used in the analysis, specify the command PRINT MATERIAL PROPERTIES.
STAAD Commands and Input Instructions 5-138 Section 5 5.26.3 Surface Constants Specification Explained below is the command syntax for specifying constants for surface entities. The attributes associated with surfaces, and the sections of this manual where the information may be obtained, are listed below: Attributes Related Sections Surfaces incidences - 5.13.3 Openings in surfaces - 5.13.3 Local coordinate system for surfaces - 1.6.3 Specifying sections for stress/force output - 5.13.
Section 5 where f is one of the following, as appropriate: Young’s Modulus (E), Poisson’s Ratio, Modulus of Rigidity (G), Weight density, Coefficient of thermal expansion, all in current units. In lieu of numerical values, built-in material names may be used for the above specification of constants. The built-in names are STEEL, CONCRETE and ALUMINUM. Example SURFACE CONSTANTS E 3150 1 TO 4 POISSON 0.17 ALL DENSITY 8.68e-005 1 TO 4 ALPHA 5.5e-006 1 TO 4 Notes: 1.
STAAD Commands and Input Instructions 5-140 Section 5 5.26.4 Modal Damping Information Purpose To define unique modal damping ratios for every mode. If all modes have the same damping, then enter damping with the Define Time History Load or with the Dynamic Loading commands. Damping may be entered here 1. EXPLICITly for some or all modes; 2. by specifying that STAAD EVALUATE each mode’s damping based on the frequency of the mode and the minimum and maximum damping entered here.
Section 5 5-141 3. Alternatively enter d1, d2, d3, etc. as the damping ratios for each mode. With the Explicit option each value can be preceded by a repetition factor (rf*damp) without spaces. For example: EXPLICIT 0.03 7*0.05 0.04 <= mode 1 damping is .03, modes 2 to 8 are .05, mode 9 is .04. If there are fewer entries than modes, then the last damping entered will apply to the remaining modes.
STAAD Commands and Input Instructions 5-142 Section 5 However they are determined, the α and β terms are entered in the CALC data above. For this example calculate the damping ratio at other frequencies to see the variation in damping versus frequency. Mode 1 3 Hz 4.0 12.0 2 8 20 4.5 Rad/sec 25.133 75.398 12.0664 50.2655 120.664 28.274 Damp Ratio .04000 .06000 .05375 .04650 .09200 .
Section 5 5.26.5 Composite Damping for Springs Purpose This command may be used to designate certain support springs as contributing to the computation of modal damping by the composite damping method. The Response Spectrum or Time History dynamic response analyses must select composite damping for this data to have any effect on results. General Format: SPRING DAMPING joint – list * ⎧ KFX f 1 ⎫ ⎨ KFY f 2 ⎬ ⎩ KFZ f 3 ⎭ Description At least one of KFX, KFY, or KFZ must be entered.
STAAD Commands and Input Instructions 5-144 Section 5 5.26.6 Member Imperfection Information Purpose To define camber and drift specifications for selected members. Drift is usually for columns and camber for beams.
Section 5 5.27 Support Specifications STAAD support specifications may be either parallel or inclined to the global axes. Specification of supports parallel to the global axes is described in Section 5.27.1. Specification of inclined supports is described in Section 5.27.2.
STAAD Commands and Input Instructions 5-146 Section 5 5.27.1 Global Support Specification Purpose This set of commands may be used to specify the SUPPORT conditions for supports parallel to the global axes. For SURFACE elements, if nodes located along a straight line are all supported identically, as in the case of the base of a wall, support generation can be performed for assigning restraints to those nodes. See the “GENERATE” option in the command syntax below.
Section 5 Description of Pinned and Fixed See Section 1.14 PINNED support is a support that has translational, but no rotational restraints. In other words, the support has no moment carrying capacity. A FIXED support has both translational and rotational restraints. A FIXED BUT support can be released in the global directions as described in release-spec (FX for force-X through MZ for moment-Z).
STAAD Commands and Input Instructions 5-148 Section 5 Notes 1) Users are urged to refer to Section 5.38 for information on specification of SUPPORTS along with the CHANGE command specifications. 2) Spring constants must be provided in the current units. 3) All spring DOF must be entered after the last non-spring DOF is specified, if both are on the same line. 4) If there are two entries for the same joint, then: a) any direction that is pinned/fixed on either will be fixed in that direction.
Section 5 The above command will generate pinned supports for all joints located between nodes No. 3 and 7 along a straight line. This may include joints explicitly defined by the user or joints generated by the program for internal use only (e.g., as a result of SET DIVISION and SURFACE INCIDENCES commands). Currently the support generation command can only be used in conjunction with the Surface element support specifications.
STAAD Commands and Input Instructions 5-150 Section 5 5.27.2 Inclined Support Specification Purpose These commands may be used to specify supports that are inclined with respect to the global axes. General Format: SUPPORT joint-list INClined ⎧ f1 f2 f3 ⎨ ⎪REF f 4 f 5 f 6 ⎩REFJT f 7 ⎫ ⎬ ⎪ ⎭ ⎧PINNED ⎨ ⎪FIXED (BUT release-spec[spring-spec.
Section 5 2 5-151 3 3m 4 1 4m Y 3m X Reference point (1, -1, 0) Figure 5.18 Inclined Support Axis System The INCLINED SUPPORT specification is based on the "Inclined Support axis system". The local x-axis of this system is defined by assuming the inclined support joint as the origin and joining it with a "reference point" with co-ordinates of f 1 , f 2 and f 3 (see figure) measured from the inclined support joint in the global coordinate system.
STAAD Commands and Input Instructions 5-152 Section 5 Notes Inclined support directions are assumed to be same as global when computing some dynamic and UBC intermediate results (e.g. global participation factors). If masses and/or forces in the free directions at inclined supports are a relatively small portion of the overall forces, then the effect should be very small.
Section 5 5-153 5.27.3 Automatic Spring Support Generator for Foundations STAAD has a facility for automatic generation of spring supports to model footings and foundation mats. This command is specified under the SUPPORT command.
STAAD Commands and Input Instructions 5-154 Section 5 Do not use this command with SET Z UP. The ELASTIC FOOTING option : If you want to specify the influence area of a joint yourself and have STAAD simply multiply the area you specified by the sub-grade modulus, use the FOOTING option. Situations where this may be appropriate are such as when a spread footing is located beneath a joint where you want to specify a spring support.
Section 5 5-155 Delaunay triangle method used in the ELASTIC MAT option, which is that the contour formed by the nodes of the mat must form a convex hull. The PLATE MAT DIR ALL option : Similar to the Plate Mat except that the spring supports are generated in all 3 directions. If the compression only option is also specified, then the compression direction will be assumed to be in the Y direction.
STAAD Commands and Input Instructions 5-156 Section 5 information on this input format. The actual spring constant used will be the subgrade modulus (f3 entered above) times the influence area (computed by Staad) times the s i values entered in the curve (so the curve stiffness values will likely be between 0.0 and 1.0). SPRINGS d 1 s 1 d 2 s 2 …… d n s n Example SUPPORTS 1 TO 126 ELASTIC MAT DIREC Y SUBG 200. 1 TO 100 PLATE MAT DIREC Y SUBG 200. YR -.01 .01 PLA MAT DIR Y SUBG 200 MUL SPRINGS -0.51 40.
Section 5 5-157 words, the region should have the shape of a convex polygon. The example below explains the method that may be used to get around a situation where a convex polygon is not available. For the model comprised of plate elements 100 to 102 in the figure below, one wishes to generate the spring supports at nodes 1 to 8.
STAAD Commands and Input Instructions 5-158 Section 5 5.27.4 Multi-linear Spring Support Specification When soil is modeled as spring supports, the varying resistance it offers to external loads can be modeled using this facility, such as when it becomes stiffer as it is compressed. Another application of this facility is when the behavior of soil in tension differs from its behavior in compression. General format: MULTILINEAR SPRINGS joint-list SPRINGS d 1 s 1 d 2 s 2 …… d n s n See Section 5.27.
Section 5 5-159 Load-Displacement characteristics of soil can be represented by a multi-linear curve. Amplitude of this curve will represent the spring characteristic of the soil at different displacement values. A typical spring characteristic of soil may be represented as the step curve as shown in the figure below. In the above example, the multi-linear spring command specifies soil spring at joints 2 and 4. (Note that the amplitude of the step curve does not change after the first point.
STAAD Commands and Input Instructions 5-160 Section 5 Figure 5.20 F = Force Units L = Length units Spring constant is always positive or zero.
Section 5 5.27.5 Spring Tension/Compression Specification Purpose This command may be used to designate certain support springs as Tension-only or Compression-only springs. General Format: SPRING TENSION joint – list spring-spec SPRING COMPRESSION joint – list spring-spec spring-spec = * ⎧KFX ⎨KFY ⎪KFZ ⎩ALL ⎫ ⎬ ⎪ ⎭ Description See Section 1.9 Tension-only springs are capable of carrying tensile forces only. Thus, they are automatically inactivated for load cases that create compression in them.
STAAD Commands and Input Instructions 5-162 Section 5 direction spring goes slack, the X and Z springs at the same joint are made inactive as well. The procedure for analysis of Tension-only or Compression-only springs requires iterations for every load case and therefore may be quite involved. Since this command does not specify whether the spring is in the positive or negative direction from the joint, it is assumed in STAAD to be in the negative direction.
Section 5 command is used. This example is for the SPRING TENSION command. Similar rules are applicable for the SPRING COMPRESSION command. The dots indicate other input data items.
STAAD Commands and Input Instructions 5-164 Section 5 … CHECK CODE … FINISH a) See Section 5.5 for explanation of the SET NL command. The number that follows this command is an upper bound on the total number of primary load cases in the file. b) STAAD performs up to 10 iterations automatically, stopping if converged. If not converged, a warning message will be in the output. Enter a SET ITERLIM i command (i>10) before the first load case to increase the default number of iterations.
Section 5 d) A revised SPRING TENSION / COMPRESSION command and its accompanying list of joints may be provided after a CHANGE command. If entered, the new SPRING commands replace all prior SPRING commands. If not entered after a CHANGE, then the previous spring definitions are used. e) The SPRING TENSION command should not be used if the following load cases are present : Response Spectrum load case, Time History Load case, Moving Load case.
STAAD Commands and Input Instructions 5-166 Section 5 5.28 Master/Slave Specification Purpose This set of commands may be used to model specialized linkages (displacement tying, rigid links) through the specification of MASTER and SLAVE joints. Please read the notes for restrictions.
Section 5 5-167 displacement at the master plus the rigid rotation, R SIN θ. Notice that instead of providing a joint list for the slaved joints, a range of coordinate values (in global system) may be used. All joints whose coordinates are within the range are assumed to be slaved joints. For convenience, the coordinate range specified for slaved joints in this entry may include the master joint for this entry. However, master and slave joints of other entries must not be included in the coordinate range.
STAAD Commands and Input Instructions 5-168 Section 5 Example - Fully Rigid and Rigid Floor Diaphragm SLAVE RIGID MASTER 22 JOINT 10 TO 45 SLAVE RIGID MASTER 70 JOINT YR 25.5 27.5 SLA ZX MAS 80 JOINT YR 34.5 35.
Section 5 5.29 Draw Specifications Purpose This command has been discontinued in STAAD.Pro. Please use the Graphical User Interface for screen and hard copy graphics.
STAAD Commands and Input Instructions 5-170 Section 5 5.30 Miscellaneous Settings for Dynamic Analysis When dynamic analysis such as frequency and mode shape calculation, response spectrum analysis and time history analysis is performed, it involves eigenvalue extraction and usage of a certain number of modes during the analysis process. These operations are built around certain default values. This section explains the commands required to override those defaults.
Section 5 5.30.1 Cut-Off Frequency, Mode Shapes or Time Purpose These commands are used in conjunction with dynamic analysis. They may be used to specify the highest frequency or the number of mode shapes that need to be considered. General Format: See Section 1.18.3 CUT (OFF) ⎧FREQUENCY f1 ⎫ ⎨MODE SHAPE i1 ⎬ t1 ⎭ ⎩TIME Where, f 1 = Highest frequency (cycle/sec) to be considered for dynamic analysis. i 1 = Number of mode shapes to be considered for dynamic analysis.
STAAD Commands and Input Instructions 5-172 Section 5 meets the convergence tolerance, then the Subspace iteration is done. If the cut off frequency f1 results in fewer modes than i1, then only those frequencies up to the cut off are used. If the cut off frequency would result in more modes than i1, then only the first i1 modes are used. That is, the modes cut off takes precedence over the frequency cut off.
Section 5 5.30.2 Mode Selection Purpose This command allows specification of a reduced set of active dynamic modes. All modes selected by this command remain selected until a new MODE SELECT is specified. General format: MODE SELECT mode_list Description This command is used to limit the modes used in dynamic analysis to the modes listed in this command and deactivate all other modes that were calculated but not listed in this command.
STAAD Commands and Input Instructions 5-174 Section 5 The advantage of this command is that one may find the amount of structural response generated from a specific mode or a set of modes. For example, if 50 modes are extracted, but the effect of just the 40 th to the 50 th mode in a response spectrum analysis is to be determined, one may set the active modes to be 40 through 50. The results will then be devoid of any contribution from modes 1 through 39.
Section 5 5.31 Definition of Load Systems Purpose This section describes the specifications necessary for defining various load systems, for automatic generation of Moving loads, UBC Seismic loads and Wind loads. In addition, this section also describes the specification of Time History load for Time History analysis. Description STAAD has built-in algorithms to generate moving loads, lateral seismic loads (per the Uniform Building Code), and wind loads on a structure.
STAAD Commands and Input Instructions 5-176 Section 5 5.31.1 Definition of Moving Load System Purpose This set of commands may be used to define the moving load system. Enter this command only once with up to 200 TYPE commands. General format: DEFINE MOVING LOAD (FILE file-name) ⎧LOAD f1,f2,.fn ( DISTANCE d1,d2,..dn-1 (WIDTH w) ) ⎫ ⎬ ⎩load-name (f) ⎭ TYPE j ⎨ ( DISTANCE d1,d2,..
Section 5 Where, j n fi di w = = = = moving load system type number (integer limit of 200 types) number of loads (e.g. axles), 2 to 200. value of conc. i th load distance between the (i+1) th load and the i th load in the direction of movement = spacing between loads perpendicular to the direction of movement. If left out, one dimensional loading is assumed. (e.g. the width of vehicle). This parameter will double the total load since the f i is applied to each wheel.
STAAD Commands and Input Instructions 5-178 Section 5 50 80 90 100 6.5 7.0 7.0 9.0 Figure 5.21 Several load systems may be repeated within the same file. The STAAD moving load generator assumes: 1) All positive loads are acting in the negative global vertical (Y or Z) direction. The user is advised to set up the structure model accordingly. 2) Resultant direction of movement is determined from the X and Z (or Y if Z is up) increments of movements as provided by the user.
Section 5 reference point x x d1 W d2 d1 d2 z reference point W z Movement parallel to global X axis Movement parallel to global Z axis Figure 5.22 Notice that in the left view, the reference point is on the positive Z wheel track side; whereas in the right view, the reference point is on the least positive X wheel track side. Specifying standard AASHTO loadings General format: See Section 1.17.1 TYPE i ⎧HS20 ⎨HS15 ⎪H20 ⎩H15 ⎫ ⎬ ⎪ ⎭ (f) ( vs ) where, i = moving load system type no.
STAAD Commands and Input Instructions 5-180 Section 5 Example DEFINE MOVING LOAD TYPE 1 LOAD 10.0 20.0 – 15.0 10.0 DISTANCE 5.0 7.5 – 6.5 WIDTH 6.0 TYPE 2 HS20 0.80 22.0 Example: When data is provided through an external file called MOVLOAD Data in input file UNIT . . . DEFINE MOVING LOAD FILE MOVLOAD TYPE 1 AXLTYP1 TYPE 2 AXLTYP2 1.25 Data in external file MOVLOAD AXLTYP1 10 20 15 5.0 7.5 6.0 AXLTYP2 20 20 10 7.
Section 5 5-181 5.31.2 Definitions for Static Force Procedures for Seismic Analysis See Sections 1.17.2 and 5.32.12 STAAD offers facilities for determining the lateral loads acting on structures due to seismic forces, using the rules available in several national codes and widely accepted publications. The codes and publications allow for so called equivalent static force methods to be used in place of more complex methods like response spectrum and time history analysis.
STAAD Commands and Input Instructions 5-182 Section 5 5.31.2.1 UBC 1997 Load Definition Purpose This feature enables one to generate horizontal seismic loads per the UBC 97 specifications using a static equivalent approach. Depending on this definition, equivalent lateral loads will be generated in horizontal direction(s). Description The seismic load generator can be used to generate lateral loads in the X & Z directions for Y up or X & Y for Z up.
Section 5 5-183 Equation 30-7 – In addition, for Seismic Zone 4, the total base shear shall also not be less than V= 0.8ZN v I W R For an explanation of the terms used in the above equations, please refer to the UBC 1997 code. There are 2 stages of command specification for generating lateral loads. This is the first stage and is activated through the DEFINE UBC LOAD command. General Format DEFINE UBC (ACCIDENTAL) LOAD ZONE f1 ubc-spec SELFWEIGHT JOINT WEIGHT Joint-list WEIGHT w [See Section 5.31.2.
STAAD Commands and Input Instructions 5-184 Section 5 f10 = Optional Period of structure (in sec) in Z (or Y if Z up)direction to be used in Method B The Soil Profile Type parameter STYP can take on values from 1 to 5. These are related to the values shown in Table 16-J of the UBC 1997 code in the following manner : STAAD Value 1 2 3 4 5 UBC 1997 code value SA SB SC SD SE The soil profile type S F is not supported.
Section 5 Steps to calculate base shear are as follows: 1. Time Period of the structure is calculated based on clause 1630.2.2.1 (Method A) and 1630.2.2.2 (Method B). 2. The user may override the period that the program calculates using Method B by specifying a value for PX or PZ (Items f9 and f10) depending on the direction of the UBC load. The specified value will be used in place of the one calculated using Method B. 3.
STAAD Commands and Input Instructions 5-186 Section 5 "h". Also, the code deals with distributing the forces only on regions above the foundation. If there are lumped weights below the foundation, it is not clear as to how one should determine the lateral forces for those regions. The following example shows the commands required to enable the program to generate the lateral loads. Users may refer to the LOAD GENERATION section of the Reference Manual for this information.
Section 5 5-187 5.31.2.2 UBC 1994 or 1985 Load Definition Purpose This set of commands may be used to define the parameters for generation of UBC-type equivalent static lateral loads for seismic analysis. Depending on this definition, equivalent lateral loads will be generated in horizontal direction(s). Description The seismic load generator can be used to generate lateral loads in the X & Z directions for Y up or X & Y for Z up.
STAAD Commands and Input Instructions 5-188 Section 5 2. Program calculates the structure period T. 3. Program calculates C from appropriate UBC equation(s) utilizing T. 4. Program calculates V from appropriate equation(s). W is obtained from the weight data (SELFWEIGHT, JOINT WEIGHT(s), etc.) provided by the user through the DEFINE UBC LOAD command. The weight data must be in the order shown. 5.
Section 5 5-189 where, = seismic zone coefficient (0.2, 0.3 etc.). Instead of using an f1 integer value like 1, 2, 3 or 4, use the fractional value like 0.075, 0.15, 0.2, 0.3, 0.4, etc. = importance factor f2 = numerical co-efficient R w for lateral load in X-direction f3 = numerical co-efficient R w for lateral load in Z-directions f4 = site co-efficient for soil characteristics f5 = horizontal force factor f6 = importance factor f7 = site characteristic period (Referred to as Ts in the UBC f8 code).
STAAD Commands and Input Instructions 5-190 Section 5 is not defined as part of the structural model. It is used in the same sort of situation in which one uses FLOOR LOADS (see section 5.32.4 for details of the Floor Load input). Notes 1) If the option ACCIDENTAL is used, the accidental torsion will be calculated per UBC specifications. The value of the accidental torsion is based on the "center of mass" for each level.
Section 5 Example DEFINE UBC LOAD ZONE 0.2 I 1.0 RWX 9 RWZ 9 S 1.5 CT 0.032 SELFWEIGHT JOINT WEIGHT 17 TO 48 WEIGHT 2.5 49 TO 64 WEIGHT 1.25 LOAD 1 UBC LOAD X 0.75 SELFWEIGHT Y -1.0 JOINT LOADS 17 TO 48 FY -2.
STAAD Commands and Input Instructions 5-192 Section 5 5.31.2.3 Colombian Seismic Load Purpose The purpose of this command is to define and generate static equivalent seismic loads as per Colombian specifications using a static equivalent approach similar to those outlined by UBC. Depending on this definition, equivalent lateral loads will be generated in horizontal direction(s). See Sections 1.17.2, 5.32.12 and Examples manual problem no.
Section 5 Base Shear, Vs is calculated as Vs = Where, W * Sa W Total weight on the structure = Total lateral seismic load, Vs is distributed by the program among different levels as, Fx = Where, Cvx = Cvx * Vs ( Wx * hxK ) / Σni=1 ( Wx * hxK ) Where, Wx hx K = = = = = Weight at the particular level Height of that particular level 1.0 when, T ≤ 0.5 sec 0.75 + 0.5 * T when, 0.5 < T ≤ 2.5 sec 2.0 when, 2.
STAAD Commands and Input Instructions 5-194 Section 5 General format to provide Colombian Seismic load in any load case: LOAD i COLOMBIAN LOAD {X/Y/Z} (f) where i and f are the load case number and factor to multiply horizontal seismic load respectively. Example DEFINE COLOMBIAN LOAD ZONE 0.38 I 1.0 S 1.
Section 5 5.31.2.4 Japanese Seismic Load Purpose The purpose of this command is to define and generate static equivalent seismic loads as per Japanese specifications using a static equivalent approach similar to those outlined by UBC. Depending on this definition, equivalent lateral loads will be generated in horizontal direction(s). See Sections 1.17.2, 5.32.12 and Examples manual problem no.
STAAD Commands and Input Instructions 5-196 Section 5 αi is calculated from the weight provided by the user in Define AIJ Load command. Seismic coefficient of floor Ci is calculated using appropriate equations Ci = Z Rt Ai Co = = = zone factor normal coefficient of shear force 1 + ( 1 / √αi - αi ) 2T/ ( 1 + 3T ) Where, Z Co Ai The total lateral seismic load is distributed by the program among different levels.
Section 5 Example DEFINE AIJ LOAD ZONE 0.8 I 0.0 CO 0.2 TC 0.
STAAD Commands and Input Instructions 5-198 Section 5 5.31.2.5 Definition of Lateral Seismic Load per Indian IS:1893 (Part 1) – 2002 Code Purpose This feature enables one to generate seismic loads per the IS:1893 specifications using a static equivalent approach. Depending on this definition, equivalent lateral loads will be generated in horizontal direction(s). See Sections 1.17.2, 5.32.12 and Examples manual problem no.
Section 5 5-199 4. Program calculates V from the above equation. W is obtained from the weight data provided by the user through the DEFINE 1893 LOAD command. [See section 5.31.2.2 for SELFWEIGHT, JOINT WEIGHT(s), etc. The weight data must be in the order shown.] 5. The total lateral seismic load (base shear) is then distributed by the program among different levels of the structure per the IS: 1893(Part 1)-2002 procedures.
STAAD Commands and Input Instructions 5-200 Section 5 ST f 5 DM f 6 PX f 7 PZ f 8 DT f 9 = Optional value for type of structure (=1 for RC frame building, 2 for Steel frame building, 3 for all other buildings). If this parameter is mentioned the program will calculate natural period as per Clause 7.6 of IS:1893(Part 1)-2002. = Damping ratio to obtain multiplying factor for calculating S a /g for different damping. If no damping is specified 5% damping (default value 0.
5-201 5.31.2.6 IBC 2000/2003 Load Definition Description See Sections 1.17.2, 5.32.12 and Examples manual problem no. 14 The specifications of the IBC 2000 and 2003 codes for seismic analysis of a building using a static equivalent approach have been implemented as described in this section. Depending on this definition, equivalent lateral loads will be generated in horizontal direction(s).
STAAD Commands and Input Instructions 5-202 Section 5 IBC 2003 On a broad basis, the rules described in section 1617.4 of the IBC 2003 code document have been implemented. This section directs the engineer to Section 9.5.5 of the ASCE 7 code. The specific section numbers of ASCE 7-2002, those which are implemented, and those which are not implemented, are shown in the table below. The associated pages of the ASCE 7-2002 code are 146 thru 149.
Section 5 5-203 The seismic response coefficient, C s , is determined in accordance with the following equation: Cs = S DS ………………. Eqn 16-35 of IBC 2000, Eqn 9.5.5.2.1-1 of ASCE 7-02 ⎡R⎤ ⎢ ⎥ ⎣ IE ⎦ C s need not exceed the following: Cs = S D1 ……………. Eqn 16-36 of IBC 2000, Eqn 9.5.5.2.1-2 of ASCE 7-02 ⎡R⎤ ⎢ ⎥T ⎣ IE ⎦ C s shall not be taken less than: C S = 0.044 S DS I E …….. Eqn 16-37 of IBC 2000, Eqn 9.5.5.2.
STAAD Commands and Input Instructions 5-204 Section 5 There are 2 stages of command specification for generating lateral loads. This is the first stage and is activated through the DEFINE IBC 2000 or 2003 LOAD command. General Format DEFINE IBC ⎧2000 ⎫ ⎬) ⎩2003 ⎭ (⎨ (ACCIDENTAL) LOAD SDS f1 ubc-spec SELFWEIGHT JOINT WEIGHT Joint-list WEIGHT w [See Section 5.31.2.
Section 5 5-205 f6 = The response modification factor for lateral load along the Z direction. See Table 1617.6 of IBC 2000 (pages 365368) and Table 1617.6.2 of IBC 2003 (page 334-337). It is used in equations 16-35, 16-36 & 16-38 of IBC 2000. f7 = Site class as defined in Section 1615.1.1 of IBC 2000 (page 350) & 2003 (page 322). Enter 1 through 6 in place of A through F, see table below). f8 = Optional CT value to calculate time period. See section 1617.4.2.1, equation 16-39 of IBC 2000 and section 9.5.
STAAD Commands and Input Instructions 5-206 Section 5 Example DEFINE IBC 2003 LOAD SDS 0.6 SD1 .36 S1 .3 I 1.0 RX 3 RZ 4 SCL 4 CT 0.032 SELFWEIGHT JOINT WEIGHT 51 56 93 100 WEIGHT 1440 101 106 143 150 WEIGHT 1000 151 156 193 200 WEIGHT 720 Steps to calculate base shear are as follows: 1. Time Period of the structure is calculated based on section 1617.4.2 of IBC 2000, and section 9.5.5.3 of ASCE 7-02. This is reported in the output as Ta. 2.
Section 5 5-207 multiplied by this lever arm to obtain the torsional moment at that joint. The following example shows the commands required to enable the program to generate the lateral loads. Users may refer to Section 5.32.12 of the Technical Reference Manual for this information. Example LOAD 1 ( SEISMIC LOAD IN X DIRECTION ) IBC LOAD X 0.75 LOAD 2 ( SEISMIC LOAD IN Z DIRECTION ) IBC LOAD Z 0.75 The Examples manual contains examples illustrating load generation involving IBC and UBC load types.
STAAD Commands and Input Instructions 5-208 Section 5 5.31.2.7 CFE (Comision Federal De Electricidad) Seismic Load Purpose The purpose of this command is to define and generate static equivalent seismic loads as per MANUAL DE DISEÑO POR SISMO - SEISMIC DESIGN HANDBOOK COMISION FEDERAL DE ELECTRICIDAD - ELECTRIC POWER FEDERAL COMISSION - October 1993 (Chapters 3.1, 3.2, 3.3 and 3.4) specifications. Depending on this definition, equivalent lateral loads will be generated in horizontal direction(s).
Section 5 The ductility reduction factor Q’ is calculated according to section 3.2.5. Q’= Q Q’= 1 + (T/T a ) (Q-1) if if T ≥ Ta T < Ts If not regular Q’ = Q’ x 0.8 If the period T s of the soil is known and the soil type II or III T a and T b will be modified according to section 3.3.2. Lateral loads for each direction are calculated for: T ≤ Tb – Eq. 4.5. Section 3.4.4.2 N P =W h n n ∑ (W n =1 n ) a n N ∑ (W h ) n =1 n n Q' T > Tb – Eq. 4.6/7/8. Section 3.4.4.
STAAD Commands and Input Instructions 5-210 Section 5 The base shear are distributed proportionally to the height if T≤ Tb or with the quadratic equation mentioned if T > Tb. The distributed base shears are subsequently applied as lateral loads on the structure. General Format DEFINE CFE LOAD ZONE f1 cfe-spec SELFWEIGHT JOINT WEIGHT Joint-list WEIGHT w [See Section 5.31.2.
Section 5 f7 = Optional Period of structure (in sec) in X-direction to be used as fundamental period of the structure instead of the value calculated by the program using Raleigh-Quotient method f8 = Optional Period of structure (in sec) in Z direction (or Y if SET Z UP is used) to be used as fundamental period of the structure instead of the value calculated by the program using Raleigh-Quotient method General format to provide RPA Seismic load in any load case: LOAD i CFE LOAD {X/Y/Z} (f) where i and
STAAD Commands and Input Instructions 5-212 Section 5 5.31.2.8 NTC (Normas Técnicas Complementarias) Seismic Load Purpose The purpose of this command is to define and generate static equivalent seismic loads as per Code of the México Federal District (Reglamento de Construcciones del Distrito Federal de México) and Complementary Technical Standards for Seismic Design (y Normas Técnicas Complementarias (NTC) para Diseño por Sismo -Nov. 1987) (Chapters 8.1 8.2 8.6 and 8.8) specifications.
Section 5 B. Base shear is given as Vo / Wo = a / Q’ Where Reduction of Shear Forces are requested Time Period T of the structure is: calculated by the program based on using Raleigh quotient technique.
STAAD Commands and Input Instructions 5-214 Section 5 Table 3.1 Values of Ta, Tb and r ZONE Ta Tb I 0.2 0.6 II not shaded 0.3 1.5 III y II shaded 0.6 3.9 r 1/2 2/3 1.0 a shall not be less than c/4 Vo for each direction is calculated Vo = Wo a/Q’ if T ≤ Tb Vo = ΣWi a/Q’ (K1 hi+K2 hi²) if T > Tb where K1 = q ( 1 – r (1-q)) Σ Wi/( Σ Wi/hi) K2 = 1.5 r q (1-q) Σ Wi/( Σ Wi/hi²) Wi and hi the weight and the height of the i th mass over the soil or embedment level.
Section 5 General Format DEFINE NTC LOAD ZONE f1 ntc-spec SELFWEIGHT JOINT WEIGHT Joint-list WEIGHT w [See Section 5.31.2.2 for complete weight input definition] ntc-spec = ⎧ ⎥ ⎥ ⎥ ⎨ ⎥ ⎥ ⎩ QX f2 ⎫ QZ f3 ⎪ GROUP f4 ⎥ (SHADOWED)⎥ (REGULAR) ⎬ (REDUCE) ⎥ (PX f6) ⎥ (PZ f7) ⎭ where, f1 = Zone number specified in number such as 1, 2, 3 or 4 f2 = seismic behavior factor of the structure along X direction as a parameter according 3.2.4.
STAAD Commands and Input Instructions 5-216 Section 5 f6 = Optional Period of structure (in sec) in X-direction to be used as fundamental period of the structure instead of the value calculated by the program using Raleigh-Quotient method f7 = Optional Period of structure (in sec) in Z or Y direction to be used as fundamental period of the structure instead of the value calculated by the program using Raleigh-Quotient method General format to provide NTC Seismic load in any load case: LOAD i NTC LOAD {X
Section 5 5.31.2.9 RPA (Algerian) Seismic Load Purpose The purpose of this command is to define and generate static equivalent seismic loads as per RPA specifications using a static equivalent approach similar to those outlined by RPA. Depending on this definition, equivalent lateral loads will be generated in horizontal direction(s). Description The seismic load generator can be used to generate lateral loads in the X & Z directions for Y up or X & Y for Z up.
STAAD Commands and Input Instructions 5-218 Section 5 Program calculates the natural period of building T utilizing clause 4.2.4 of RPA 99. Design spectral coefficient (D) is calculated utilizing T as, D = 2.5 η when, 0 ≤ T ≤ T2 = 2.5 η . (T2 /T) 2/3 when, T2 < T ≤ 3.0 sec = 2.5 η . (T2 /3) 2/3 . (3/T) 5/3 when, T > 3.0 sec where η = factor of damping adjustment ………….. Eq. 4.3 T 2 = specific period ………………………….Table 4.7 Total lateral seismic load, V is distributed by the program among different levels.
Section 5 rpa-spec = ⎧ ⎥ ⎥ ⎥ ⎨ ⎥ ⎥ ⎩ Q f2 ⎫ RX f3 ⎪ RZ f4 ⎥ STYP f5 ⎥ CT f6 ⎬ CRDAMP f7 ⎥ f8) ⎥ (PX f9) ⎭ (PZ where f1 = Seismic zone coefficient. Instead of using an integer value like 1, 2, 3 or 4, use the fractional value like 0.08, 0.15, 0.2, 0.3, 0.05, etc. f2 = Importance factor f3 = Coefficient R for lateral load in X direction – table 4.3 f4 = Coefficient R for lateral load in Z direction – table 4.3 f5 = Soil Profile Type f6 = Coefficient from table 4.
STAAD Commands and Input Instructions 5-220 Section 5 Example DEFINE RPA LOAD A 0.15 Q 1.36 STYP 2 RX 3 RZ 4 CT 0.0032 – CRDAMP 30 PX .027 PZ 0.025 JOINT WEIGHT 51 56 93 100 WEIGHT 1440 101 106 143 150 WEIGHT 1000 151 156 193 200 WEIGHT 720 LOAD 1 ( SEISMIC LOAD IN X DIRECTION ) RPA LOAD X 1.
Section 5 5-221 5.31.2.10 Canadian Seismic Code (NRC) - 1995 Purpose This set of commands may be used to define the parameters for generation of equivalent static lateral loads for seismic analysis per National Building Code(NRC/CNRC) of Canada- 1995 edition. Depending on this definition, equivalent lateral loads will be generated in horizontal direction(s). Description The seismic load generator can be used to generate lateral loads in the X & Z directions for Y up or X & Y for Z up.
STAAD Commands and Input Instructions 5-222 Section 5 R = Force modification factor conforming to Table 4.9.1.B that reflects the capability of a structure to dissipate energy through inelastic behaviour. STAAD utilizes the following procedure to generate the lateral seismic loads. 1. User provides seismic zone co-efficient and desired "nrc-spec" (1995) through the DEFINE NRC LOAD command. 2.
Section 5 General format: DEFINE NRC LOAD *nrc-spec SELFWEIGHT JOINT WEIGHT joint-list WEIGHT w MEMBER WEIGHT ⎧UNI v1 v2 v3 ⎫ mem-list ⎨ ⎬ ⎩ CON v 4 v 5 ⎭ ELEMENT WEIGHT plate-list PRESS p 1 FLOOR WEIGHT YRANGE … (see Section 5.32.
STAAD Commands and Input Instructions 5-224 Section 5 where, f1 f2 f3 f4 = Zonal velocity ratio per Appendix C = Factor for acceleration related seismic zone per Appendix C = Factor for velocity related seismic zone per Appendix C = Force modification factor along X-direction that reflects the capability of a structure to dissipate energy through inelastic behaviour. Please refer Table 4.1.9.
Section 5 5-225 Floor Weight is used if the pressure is on a region bounded by beams, but the entity which constitutes the region, such as a slab, is not defined as part of the structural model. It is used in the same sort of situation in which one uses FLOOR LOADS (see section 5.32.4 of STAAD Technical Reference Manual for details of the Floor Load inpuut). The weights have to be input in the order shown.
STAAD Commands and Input Instructions 5-226 Section 5 T c = Time period calculated per sentence 7(c) of section 4.1.9.1 CALC / USED PERIOD The CALC PERIOD is the period calculated using the Rayleigh method. For NRC in the x-direction, the USED PERIOD is PX. For the NRC in the z-direction (or Y direction if SET Z UP is used), the USED PERIOD is PZ. If PX and PZ are not provided, then the used period is the same as the calculated period for that direction.
Section 5 5-227 Input: STAAD SPACE EXAMPLE PROBLEM FOR CANADIAN NRC LOADING UNIT METER KN JOINT COORDINATES 1 0 0 0 4 10.5 0 0 REPEAT 3 0 0 3.5 REPEAT ALL 3 0 3.5 0 MEMBER INCIDENCES 101 17 18 103 104 21 22 106 107 25 26 109 110 29 30 112 REPEAT ALL 2 12 16 201 17 21 204 205 21 25 208 209 25 29 212 REPEAT ALL 2 12 16 301 1 17 348 MEMBER PROPERTY CANADIAN 101 TO 136 201 TO 236 PRIS YD 0.4 ZD 0.3 301 TO 348 TABLE ST W460X52 DEFINE MATERIAL START ISOTROPIC CONCRETE E 2.17184e+007 POISSON 0.17 DENSITY 23.
STAAD Commands and Input Instructions 5-228 Section 5 DAMP 0.03 END DEFINE MATERIAL CONSTANTS MATERIAL CONCRETE MEMB 101 TO 136 201 TO 236 MATERIAL STEEL MEMB 301 TO 348 SUPPORTS 1 TO 16 FIXED DEFINE NRC LOAD V 0.2 ZA 4 ZV 4 RX 4 RZ 4 I 1.3 F 1.3 CT 0.35 PX 2 SELFWEIGHT JOINT WEIGHT 17 TO 48 WEIGHT 7 49 TO 64 WEIGHT 3.5 LOAD 1 EARTHQUAKE ALONG X NRC LOAD X 1.0 PDELTA ANALYSIS PRINT LOAD DATA CHANGE LOAD 2 EARTHQUAKE ALONG Z NRC LOAD Z 1.
Section 5 2 1.0 3 1.0 PERFORM ANALYSIS LOAD LIST ALL PRINT SUPPORT REACTION FINISH Output: - 1. STAAD SPACE EXAMPLE PROBLEM FOR CANADIAN NRC LOADING 3. UNIT METER KN 4. JOINT COORDINATES 5. 1 0 0 0 4 10.5 0 0 6. REPEAT 3 0 0 3.5 7. REPEAT ALL 3 0 3.5 0 9. MEMBER INCIDENCES 10. 101 17 18 103 11. 104 21 22 106 12. 107 25 26 109 13. 110 29 30 112 14. REPEAT ALL 2 12 16 15. 201 17 21 204 16. 205 21 25 208 17. 209 25 29 212 18. REPEAT ALL 2 12 16 19. 301 1 17 348 21. MEMBER PROPERTY CANADIAN 22.
STAAD Commands and Input Instructions 5-230 Section 5 P R O B L E M S T A T I S T I C S ----------------------------------NUMBER OF JOINTS/MEMBER+ELEMENTS/SUPPORTS = 64/ 120/ ORIGINAL/FINAL BAND-WIDTH= 16/ 14/ 78 DOF TOTAL PRIMARY LOAD CASES = 1, TOTAL DEGREES OF FREEDOM = SIZE OF STIFFNESS MATRIX = 23 DOUBLE KILO-WORDS REQRD/AVAIL. DISK SPACE = 12.4/ 38909.8 MB 16 288 LOADING 1 EARTHQUAKE ALONG X ----------***************************************************************************** * * * EQUIV.
Section 5 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 FX FX FX FX FX FX FX FX FX FX FX FX FX FX FX FX 1.416 1.906 1.906 1.416 1.906 2.396 2.396 1.906 1.906 2.396 2.396 1.906 1.416 1.906 1.906 1.416 ----------TOTAL = 30.496 MY MY MY MY MY MY MY MY MY MY MY MY MY MY MY MY 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ----------0.000 AT LEVEL 10.500 METE ************ END OF DATA FROM INTERNAL STORAGE ************ 57. 59. 60. 61.
STAAD Commands and Input Instructions 5-232 Section 5 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 FZ FZ FZ FZ FZ FZ FZ FZ 1.637 1.980 1.980 1.637 1.294 1.637 1.637 1.294 ----------TOTAL = 26.189 MY MY MY MY MY MY MY MY 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ----------0.000 AT LEVEL 7.000 METE FZ FZ FZ FZ FZ FZ FZ FZ FZ FZ FZ FZ FZ FZ FZ FZ MY MY MY MY MY MY MY MY MY MY MY MY MY MY MY MY 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.
Section 5 5 6 7 8 9 10 11 12 13 14 15 16 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 -3.23 0.00 0.45 -2.77 0.45 -4.13 0.00 0.01 -4.12 0.01 -4.13 0.00 -0.01 -4.14 -0.01 -3.22 0.00 -0.45 -3.68 -0.45 -3.23 0.00 0.45 -2.77 0.45 -4.13 0.00 0.01 -4.12 0.01 -4.13 0.00 -0.01 -4.14 -0.01 -3.22 0.00 -0.45 -3.68 -0.45 -3.13 0.00 0.45 -2.68 0.45 -4.01 0.00 0.01 -4.00 0.01 -4.01 0.00 -0.01 -4.03 -0.01 -3.13 0.00 -0.45 -3.58 -0.
STAAD Commands and Input Instructions 5-234 Section 5 5.31.3 Definition of Wind Load Purpose This set of commands may be used to define some of the parameters for generation of wind loads on the structure. See section 5.32.12, Generation of Wind Loads, for the definition of wind direction and the possible surfaces to be loaded. Section 1.17.3 of this manual describes the two types of structures on which this load generation can be performed. See Section 1.17.3, 5.32.12 and Examples manual problem no.
Section 5 5-235 e 1 ,e 2 ,e 3 ...e m exposure factors. A value of 1.0 means that the wind force may be applied on the full influence area associated with the joint(s) if they are also exposed to the wind load direction. Limit: 99 factors. joint-list Joint list associated with Exposure Factor (joint numbers or “TO” or “BY”) or enter only a group name. global coordinate values to specify Y (or Z if Z UP) f 1 and f 2 vertical range for Exposure Factor.
STAAD Commands and Input Instructions 5-236 Section 5 then it defaults to 1.0 for those joints; in which case the entire influence area associated with the joint(s) will be considered. For load generation on a closed type structure defined as a PLANE FRAME, influence area for each joint is calculated considering unit width perpendicular to the plane of the structure. The user can accommodate the actual width by incorporating it in the Exposure Factor as follows.
Section 5 5-237 The Intensity line can be continued in up to 12 lines. So the following INT 0.008 0.009 0.009 0.009 0.01 0.01 0.01 0.011 0.011 0.012 0.012 0.012 HEIG 15 20 25 30 40 50 60 70 80 90 100 120 could be split as INT 0.008 0.009 0.009 0.009 0.01 0.01 0.01 0.011 0.011 0.012 0.012 0.012 – HEIG 15 20 25 30 40 50 60 70 80 90 100 120 or INT 0.008 0.009 0.009 0.009 0.01 0.010.01 0.011 0.011 0.012 0.012 0.012 HEIG 15 20 25 30 40 50 60 70 80 90 100 120 etc.
STAAD Commands and Input Instructions 5-238 Section 5 5.31.4 Definition of Time History Load Purpose This set of commands may be used to define parameters for Time History loading on the structure. General format: DEFINE TIME HISTORY (DT x) TYPE i ⎧ ACCELERATION ⎨ ⎩ FORCE or MOMENT ⎧READ f n ( f8 ) ⎨ - OR ⎪ t 1 p 1 t 2 p 2 ....
Section 5 x = i = Scale f 7 = Save = t1 p1 t2 p2 5-239 solution time step used in the step-by-step integration of the uncoupled equations. Values smaller than 0.00001 will be reset to the default DT value of 0.0013888 seconds. type number of time varying load (integer). Up to 136 types may be provided. ACCELERATION indicates that the time varying load type is a ground motion. FORCE or MOMENT indicates that it is a time varying force or moment. This number should be sequential.
STAAD Commands and Input Instructions 5-240 Section 5 time. Zero force will be assumed for all times after the last data point. a 1 a 2 a 3 ... a n = Values of the various possible arrival times (seconds) of the various dynamic load types. Arrival time is the time at which a load type begins to act at a joint (forcing function) or at the base of the structure (ground motion). The same load type may have different arrival times for different joints and hence all those values must be specified here.
Section 5 5-241 f 5 - time step of loading, default = one twelfth of the period corresponding to the frequency of the harmonic loading. It is best to use the default; or f 6 - subdivide a ¼ cycle into this many integer time steps. Default = 3. f 5 or f 6 is used only to digitize the forcing function. It is not the DT used to integrate for the responses. More subdivisions or smaller step size will make the digitized force curve more closely match a sine wave. The default is usually adequate.
STAAD Commands and Input Instructions 5-242 Section 5 The data in the external file must be provided as one or more timeforce pairs per line as shown in the following example. Data in Input file UNIT . . . DEFINE TIME HISTORY TYPE 1 FORCE READ THFILE ARRIVAL TIME 0.0 DAMPING 0.075 Data in the External file “THFILE” 0.0 2.0 3.0 4.0 1.0 1.8 2.2 2.6 1.0 1.2 Example for Harmonic Loading Generator UNIT . . .
Section 5 To define more than one sinusoidal load, the input specification is as follows : DEFINE TIME HISTORY TYPE 1 FORCE FUNCTION SINE AMPLITUDE 1.925 RPM 10794.0 CYCLES 1000 TYPE 2 FORCE FUNCTION SINE AMPLITUDE 1.511 RPM 9794.0 CYCLES 1000 TYPE 3 FORCE FUNCTION SINE AMPLITUDE 1.488 RPM 1785.0 CYCLES 1000 ARRIVAL TIME 0.0 0.0013897 0.0084034 DAMPING 0.04 Notes 1) By default the response (displacements, forces etc.
STAAD Commands and Input Instructions 5-244 Section 5 5.31.5 Definition of Snow Load Purpose This set of commands may be used to define some of the parameters for generation of snow loads on the structure. See section 5.32.13, Generation of Snow Loads, for the definition of additional parameters and the surfaces to be loaded. General Format: DEFINE SNOW LOAD TYPE f1 PG f2 CE f3 CT f4 IM f5 Where f1 Snow Load Type number (limit of 100). f2 Ground snow load parameter (force per unit area).
Section 5 5-245 5.32 Loading Specifications Purpose This section describes the various loading options available in STAAD. The following command may be used to initiate a new load case. LOADING i 1 (LOADTYPE LIVE REDUCIBLE) (any load title) i 1 = any unique integer number (up to five digits) to identify the load case. This number need not be sequential with the previous load number.
STAAD Commands and Input Instructions 5-246 Section 5 Load command will be used in defining the weight moment of inertias at joints. For slave joint directions, the associated joint weight or weight moment of inertia will be moved to the master. In addition, the translational weights at slave joint directions will be multiplied by the square of the distance to the master to get the additional weight moment of inertia at the master. Cross product weight moment of inertias at the master will be ignored.
Section 5 5.32.1 Joint Load Specification Purpose This set of commands may be used to specify JOINT loads on the structure. For dynamic mass modeling see sections 5.32 and 1.18.3. General format: JOINT LOAD joint-list * ⎧FX ⎪FY ⎨FZ ⎪MX ⎪MY ⎩MZ f1 ⎫ f2 ⎪ f3 ⎬ f4 ⎪ f5 ⎪ f6 ⎭ FX, FY and FZ specify a force in the corresponding global direction (even at inclined support joints). MX, MY and MZ specify a moment in the corresponding global direction. f 1 , f 2 ... f 6 are the values of the loads.
STAAD Commands and Input Instructions 5-248 Section 5 5.32.2 Member Load Specification Purpose This set of commands may be used to specify MEMBER loads on frame members.
Section 5 f4 = f 14 = LIN TRAP close to parallel) local axis. The local x component of force is not offset. If global or projected load is selected, then the local Y component of load is offset the f 4 distance; the local Z component is offset the f 4 distance; and the local X component is not offset. -OR- [The following f 4 and f 14 are not yet implemented] If f 14 is not blank, then f 4 is the perpendicular local y distance from the member shear center to the local z-plane of loading.
STAAD Commands and Input Instructions 5-250 Section 5 start and end distances are measured along the member length and not the projected length. Notes See Section 1.16.2 In earlier versions of STAAD, the LINear type of member load could be applied only along the local axis of the member. It has been modified to allow for global and projected axes directions also.
Section 5 5.32.3 Element Load Specifications This set of commands may be used to specify various types of loads on plate and solid elements.
STAAD Commands and Input Instructions 5-252 Section 5 5.32.3.1 Element Load Specification - Plates Purpose This command may be used to specify various types of ELEMENT LOADS for plates. General format: ELEMENT LOAD ( PLATE ) element-list ⎧ ⎧ GX ⎫ ⎪ PRESSURE ⎨ GY ⎬ ⎪ ⎩ GZ ⎭ ⎪ ⎨ ⎪ ⎧ GX ⎫⎧ X ⎫ ⎪ TRAP ⎨ GY ⎬⎨ Y ⎬ ⎩ ⎩ GZ ⎭ ⎩ JT ⎭ ⎫ p 1 (x 1 y 1 x 2 y 2 ) ⎪ f1 f2 f1 f2 f1 f2 f3 f4 ⎪ ⎪ ⎬ ⎪ ⎪ ⎭ Description The PRESSURE option should be used when a UNIFORM pressure needs to be specified.
Section 5 GX,GY,GZ Global direction specification for pressure denotes global X, Y, or Z direction respectively. Local Y X2 Y2 Local X X1 Y1 Uniformly Loaded Area Figure 5.23 See Section 1.6 p1 x 1 ,y 1 & x 2 ,y 2 Uniformly Varying Press. (Trap Y) Element pressure (force/square of length) or concentrated load (force). p 1 is assumed as a concentrated load if x 2 and y 2 are omitted. Co-ordinate values in the local co-ordinate system Local Y Local X Uniformly Varying Press. (Trap X) Figure 5.
STAAD Commands and Input Instructions 5-254 Section 5 X or Y f1 f2 Direction of variation of element pressure. The TRAP X/Y option indicates that the variation of the Trapezoid is in the local X or in the local Y direction. The load acts in the global direction if selected, otherwise in the local Z axis. Pressure intensity at start. Pressure intensity at end. Alternatively the TRAP and JT options may be selected together in order to specify the actual pressures at the joints.
Section 5 Example LOAD 4 ELEMENT LOAD 1 7 TO 10 PR 2.5 11 12 PR 2.5 1.5 2.5 5.5 4.5 15 TO 25 TRAP X 1.5 4.5 15 TO 20 TRAP GY JT 1.5 4.5 2.5 5.5 34 PR 5.0 2.5 2.5 35 TO 45 PR -2.5 15 25 TRAP GX Y 1.5 4.
STAAD Commands and Input Instructions 5-256 Section 5 5.32.3.2 Element Load Specification - Solids Purpose Two types of loads can be assigned on the individual faces of solid elements: 1. 2. A uniform pressure A volumetric type of pressure on a face where the intensity at one node of the face can be different from that at another node on the same face. An example of such a load is the weight of water on the sloping face of a dam.
Section 5 f 1 f 2 f 3 f 4 …Pressure values at the joints for each 3 or 4 joint face defined. Only f 1 needs to be specified for uniform pressure. In any case the pressure is provided over the entire face. i 1 is one of six face numbers to receive the pressure for the solids selected. See figure 1.15 in section 1.6.2 for the following face definitions. Enter a pressure on all 4 joints even if the face is collapsed to 3 points.
STAAD Commands and Input Instructions 5-258 Section 5 5.32.3.3 Element Load Specification - Joints Purpose This command may be used to specify various types of element like loads for joints. Three or four joints are specified that form a plane area; pressure is specified for that area; then STAAD computes the equivalent joint loads. This command may be used as an alternative or supplement for the Area Load, Floor Load, and the other Element Load commands.
Section 5 5-259 Example LOAD 4 ELEMENT LOAD JOINT 1 by 1 2 by 1 32 by 1 31 by 1 – FACETS 5 PR GY 10 10 15 15 The above data is equivalent to the following : LOAD 4 ELEMENT LOAD JOINT 1 2 32 31 FACETS 1 PRESSURE 2 3 33 32 FACETS 1 PRESSURE 3 4 34 33 FACETS 1 PRESSURE 4 5 35 34 FACETS 1 PRESSURE 5 6 36 35 FACETS 1 PRESSURE GY GY GY GY GY 10 10 10 10 10 10 10 10 10 10 15 15 15 15 15 15 15 15 15 15 So, the value following the word FACETS is like a counter for generation, indicating how many element face
STAAD Commands and Input Instructions 5-260 Section 5 Notes: If a pressure or volumetric load is acting on a region or surface, and the entity which makes up the surface, like a slab, is not part of the structural model, one can apply the pressure load using this facility. The load is defined in terms of the pressure intensity at the 3 or 4 nodes which can be treated as the corners of the triangular or quadrilateral plane area which makes up the region.
Section 5 5.32.3.4 Surface Loads Specification The following loading options are available for surface entities: Uniform pressure on full surface General Format LOAD n SURFACE LOAD surface-list PRESSURE ⎧ GX ⎨ GY ⎩ GZ ⎫ ⎬ w ⎭ GX, GY and GZ : Global X, Y and Z directions. If the direction is omitted, the load will act along the local Z axis of the surface w = Value of pressure. Negative value indicates load acts opposite to the direction of the axis specified.
STAAD Commands and Input Instructions 5-262 Section 5 x1, y1 = Local X and Y coordinates of the corner nearest to the surface origin of the loaded region. Measured from the origin of the surface, in the local coordinate system of the surface. x2, y2 = Local X and Y coordinates of the corner farthest from the surface origin of the loaded region. Measured from the origin of the surface, in the local coordinate system of the surface.
Section 5 LOAD 3 Partial Area Load SURFACE LOAD 23 25 PRE GY -250 4 4.3 8 9.5 The attributes associated with surfaces, and the sections of this manual where the information may be obtained, are listed below: Attributes Related Sections Surfaces incidences - 5.13.3 Openings in surfaces - 5.13.3 Local coordinate system for surfaces - 1.6.3 Specifying sections for stress/force output - 5.13.3 Property for surfaces - 5.21.2 Material constants - 5.26.3 Surface loading - 5.32.3.
STAAD Commands and Input Instructions 5-264 Section 5 5.32.4 Area Load/Oneway Load/Floor Load Specification Purpose These commands may be used to specify AREA LOADs, ONEWAY LOADs or FLOOR LOADs on a structure based on members only. They are used mostly when the entity transmitting the load, such as a slab, is not part of the structural model. The AREA LOAD or ONEWAY LOAD may be used for modeling oneway distribution and the FLOOR LOAD may be used for modeling two-way distribution.
Section 5 Note Area load should not be specified on members declared as MEMBER CABLE, MEMBER TRUSS or MEMBER TENSION.
STAAD Commands and Input Instructions 5-266 Section 5 where: f1 f2 Global coordinate values to specify Y, X, or Z range. The floor/oneway load will be calculated for all members lying in that global plane within the first specified global coordinate range. The value of the floor/oneway load (unit weight over f3 square length unit). If Global direction is omitted, then this load acts parallel to the positive global Y if command begins with YRA and based on the area projected on a X-Z plane.
Section 5 5-267 Notes 1. The structure has to be modeled in such a way that the specified global axis remains perpendicular to the floor plane(s). For the FLOOR LOAD specification, a two-way distribution of the load is considered. For the ONEWAY and AREA LOAD specification, a one-way action is considered. For ONE WAY loads, the program attempts to find the shorter direction within panels for load generation purposes.
STAAD Commands and Input Instructions 5-268 Section 5 The load distribution pattern depends upon the shape of the panel. If the panel is Rectangular, the distribution will be Trapezoidal and triangular as explained in the following diagram. X 6 Z 4 6 4 Figure 5.
Section 5 5-269 For a panel that is not rectangular, the distribution is described in following diagram. First, the CG of the polygon is calculated. Then, each corner is connected to the CG to form triangles as shown. For each triangle, a vertical line is drawn from the CG to the opposite side. If the point of intersection of the vertical line and the side falls outside the triangle, the area of that triangle will be calculated and an equivalent uniform distributed load will be applied on that side.
STAAD Commands and Input Instructions 5-270 Section 5 11' 1 10' X 3 2 1 2 8 7 6' B 5 4 3 6 A 10 10' 9 C 5 4 6 7 8 Z Figure 5.28 If the entire floor has a load of 0.25 (force/unit area), then the input will be as follows: ... LOAD 2 FLOOR LOAD YRA 12.0 12.0 FLOAD -0.25 ... If in the above example, panel A has a load of 0.25 and panels B and C have a load of 0.5, then the input will be as follows: Note the usage of XRANGE, YRANGE and ZRANGE specifications. … LOAD 2 FLOOR LOAD YRA 11.9 12.
Section 5 Illustration of Notes Item (6) for FLOOR LOAD The attached example illustrates a case where the floor has to be sub-divided into smaller regions for the floor load generation to yield proper results. The internal angle at node 6 between the sides 108 and 111 exceeds 180 degrees. A similar situation exists at node 7 also. As a result, the following command LOAD 1 FLOOR LOAD YRANGE 11.9 12.1 FLOAD –0.35 will not yield acceptable results.
STAAD Commands and Input Instructions 5-272 Section 5 3) The global horizontal direction options (GX and GZ) enables one to consider AREA LOADs, ONEWAY LOADSs and FLOOR LOADs for mass matrix for frequency calculations. 4) For ONE WAY loads, the program attempts to find the shorter direction within panels for load generation purposes. So, if any of the panels are square in shape, no load will be generated on the members circumscribing those panels. In such cases, one ought to use the FLOOR LOAD type.
Section 5 5-273 b) After the load is specified, if the user decides to change the geometry of the structure (X, Y or Z coordinates of the nodes of the regions over which the floor load is applied), she/he has to go back to the load and modify its data too, such as the XRANGE, YRANGE and ZRANGE values. In other words, the 2 sets of data are not automatically linked. The above limitations may be overcome using a FLOOR GROUP.
STAAD Commands and Input Instructions 5-274 Section 5 Live load reduction per UBC and IBC Codes The UBC 1997, IBC 2000 and IBC 2003 codes permit reduction of floor live loads under certain situations. The provisions of these codes have been incorporated in the manner described further below. To utilize this facility, the following conditions have to be met when creating the STAAD model. 1. The live load must be applied using the FLOOR LOAD or ONEWAY LOAD option.
Section 5 5-275 Figure 5.32 Details of the code implementation: Code name UBC 1997 Section of code which has been implemented 1607.5, page Applicable equations Equation 7-1 R = r(A-150) for FPS units R = r(A-13.94) for SI units IBC 2000 1607.9.2, page 302 Equation 16-2 R = r(A-150) for FPS units R = r(A-13.94) for SI units IBC 2003 1607.9.2, page 277 Equation 16-22 R = r(A-150) for FPS units R = r(A-13.
STAAD Commands and Input Instructions 5-276 Section 5 In the above equations, A = area of floor supported by the member R = reduction in percentage R = rate of reduction equal to 0.08 for floors. Notes: 1. Only the rules for live load on Floors have been implemented. The rules for live load on Roofs have not been implemented. 2.
Section 5 structure satisfies this requirement. If it does not, then the reduction should not be applied. STAAD does not check this condition by itself. 6. Because all the three codes follow the same rules for reduction, no provision is made available in the command syntax for specifying the code name according to which the reduction is to be done.
STAAD Commands and Input Instructions 5-278 Section 5 5.32.5 Prestress Load Specification Purpose This command may be used to specify PRESTRESS loads on members of the structure. General Format: MEMBER ⎧PRESTRESS ⎫ ⎨ ⎬ ⎩POSTSTRESS ⎭ * member-list FORCE f1 ⎧ES ⎨EM ⎩EE (LOAD) f2 f3 f4 ⎫ ⎬ ⎭ = Prestressing force. A positive value indicates precompression in the direction of the local x-axis. A negative value indicates pretension.
Section 5 5-279 Example MEMBER PRESTRESS 2 TO 7 11 FORCE 50.0 MEMBER POSTSTRESS 8 FORCE 30.0 ES 3.0 EM -6.0 EE 3.0 In the first example, a prestressing force of 50 force units is applied through the centroid (i.e. no eccentricity) of members 2 to 7 and 11. In the second example, a poststressing force of 30 force units is applied with an eccentricity of 3 length units at the start, 6.0 at the middle, and 3.0 at the end of member 8.
STAAD Commands and Input Instructions 5-280 Section 5 Correct Input LOAD 1 MEMBER PRESTRESS 6 7 FORCE 100 ES 2 EM -3 EE 2 LOAD 2 MEMBER PRESTRESS 6 FORCE 150 ES 3 EM -6 EE 3 LOAD COMBINATION 3 1 1.0 2 1.0 PERFORM ANALYSIS Examples for Modeling Techniques The following examples describe the partial input data for the members and cable profiles shown below. Example 1 3 3 3 10ft Figure 5.33 JOINT COORD 1 0 0 ; 2 10 0 MEMB INCI 112 . .. UNIT . . .
Section 5 5-281 Example 2 3 3 20 ft Figure 5.34 JOINT COORD 1 0 0 ; 2 20 0 MEMB INCI 112 . . . UNIT . . .
STAAD Commands and Input Instructions 5-282 Section 5 Example 3 3 3 3 5 ft 10 ft Figure 5.35 JOINT COORD 1 0 0 ; 2 5 0 ; 3 15 0 0 ; 4 20 0 MEMB INCI 112;223;334 . . . UNIT . . .
Section 5 5-283 Example 4 3 3 3 20 ft Figure 5.36 JOINT COORD 1 0 0 ; 2 10 0 ; 3 20 0 0 MEMB INCI 112;223 . . . UNIT . . .
STAAD Commands and Input Instructions 5-284 Section 5 Example 5 3 3 3 3 3 10 ft 10 ft Figure 5.37 JOINT COORD 1 0 0 ; 2 10 0 ; 3 20 0 0 MEMB INCI 112;223 . . . UNIT . . .
Section 5 5.32.6 Temperature Load Specification for Members, Plates, and Solids Purpose This command may be used to specify TEMPERATURE loads or strain loads on members, plates, and solids; or strain loads on members. General format: TEMPERATURE LOAD memb/elem-list See Section 1.16.
STAAD Commands and Input Instructions 5-286 Section 5 Example UNIT MMS TEMP LOAD 1 TO 9 15 17 TEMP 70.0 18 TO 23 TEMP 90.0 66.0 8 TO 13 STRAIN 3.0 15 27 STRAINRATE 0.4E -4 Note It is not necessary or possible to specify the units for temperature or for ALPHA. The user must ensure that the value provided for ALPHA is consistent in terms of units with the value provided for the temperature load. (see Section 5.26).
Section 5 5-287 5.32.7 Fixed-End Load Specification Purpose This command may be used to specify FIXED-END loads on members (beams only) of the structure. General format: FIXED ( END ) LOAD Member_list FXLOAD f 1 , f 2 , ..... f 12 member_list = normal Staad member list rules (TO and BY for generation; and - to continue list to next line). See Section 1.16.4 f 1 ... f 6 = Force-x, shear-y, shear-z, torsion, moment-y, moment-z (all in local coordinates) at the start of the member. f 7 ...
STAAD Commands and Input Instructions 5-288 Section 5 5.32.8 Support Joint Displacement Specification Purpose This command may be used to specify DISPLACEMENTs (or generate loads to induce specified displacements) in supported directions (pinned, fixed, enforced, or spring). General format: SUPPORT DISPLACEMENT support joint-list See Section 1.16.7 ⎧FX ⎪FY ⎨FZ ⎪MX ⎪MY ⎩MZ ⎫ ⎪ ⎬ ⎪ ⎪ ⎭ f1 FX, FY, FZ specify translational displacements in X, Y, and Z directions respectively.
Section 5 5-289 DISPLACEMENT MODE With this mode, the support joint displacement is modeled as an imposed joint displacement. The joint directions where displacement may be specified must be defined (same for all cases) in the SUPPORT command, see section 5.27.1. Any beam members, springs or finite elements will be considered in the analysis. Other loading, inclined supports, and master/slave are all considered. Any number of cases may have displacements entered.
STAAD Commands and Input Instructions 5-290 Section 5 (results are superimposed). Only those cases with displacements entered will be affected. Load Mode Restrictions Support Displacements can be applied in up to 4 load cases only. The Support Displacement command may be entered only once per case. Finite elements should not be entered. Inclined supports must not be entered.
Section 5 5.32.9 Selfweight Load Specification Purpose This command may be used to calculate and apply the SELFWEIGHT of the structure for analysis. General format: SELFWEIGHT ⎧X ⎫ ⎨Y ⎬ ⎩Z ⎭ f1 This command is used if the self-weight of the structure is to be considered. The self-weight of every active member is calculated and applied as a uniformly distributed member load. X, Y, & Z represent the global direction in which the selfweight acts. f 1 = The factor to be used to multiply the selfweight.
STAAD Commands and Input Instructions 5-292 Section 5 5.32.10 Dynamic Loading Specification Purpose The command specification needed to perform response spectrum analysis and time-history analysis is explained in the following sections. Related topics can be found in the following sections: CUT OFF MODE - 5.30.1 CUT OFF FREQUENCY - 5.30.1 CUT OFF TIME - 5.30.1 MODE SELECTION - 5.30.
Section 5 5.32.10.1 Response Spectrum Specification Purpose This command may be used to specify and apply the RESPONSE SPECTRUM loading for dynamic analysis.
STAAD Commands and Input Instructions 5-294 Section 5 ACC or DIS indicates whether Acceleration or Displacement spectra will be entered. SCALE f4 = Scale factor by which the spectra data will be multiplied. Usually to factor g’s to length/sec 2 units. DAMP , CDAMP , MDAMP. Select source of damping input. f5 = Damping ratio for all modes. Default value is 0.05 (5% damping if 0 or blank entered). DAMP indicates to use the f5 value for all modes.
Section 5 5-295 ZPA f7 = For use with MIS option only. Defaults to 33 Hz if not entered. Value is printed but not used if MIS f6 is entered. FF1 f8 = The f1 parameter defined in the ASCE 4-98 standard in Hz units. For ASCE option only. Defaults to 2 Hz if not entered. FF2 f9 = The f2 parameter defined in the ASCE 4-98 standard in Hz units. For ASCE option only. Defaults to 33 Hz if not entered.
STAAD Commands and Input Instructions 5-296 Section 5 remaining spectrum cases. The format is shown below. fn may not be more than 72 characters in length. Modal Combination Description SRSS CQC ASCE ABS Square Root of Summation of Squares method. Complete Quadratic Combination method. Default. ASCE4-98 method. Absolute sum. (Very conservative worst case) TEN Ten Percent Method of combining closely spaced modes. NRC Reg. Guide 1.92 (1976). Description See Sections 1.18.3, 5.30, and 5.
Section 5 Example LOAD 2 SPECTRUM IN X-DIRECTION SELFWEIGHT X 1.0 SELFWEIGHT Y 1.0 SELFWEIGHT Z 1.0 JOINT LOAD 10 FX 17.5 10 FY 17.5 10 FZ 17.5 SPECTRUM SRSS X 1.0 ACC SCALE 32.2 0.20 0.2 ; 0.40 0.25 ; 0.60 0.35 ; 0.80 0.43 ; 1.0 0.47 1.2 0.5 ; 1.4 0.65 ; 1.6 0.67 ; 1.8 0.55 ; 2.0 0.43 Multiple Response Spectra If there is more than one response spectrum defined in the input file, the load data should accompany the first set of spectrum data only.
STAAD Commands and Input Instructions 5-298 Section 5 FILE FORMAT FOR SPECTRA DATA The format of the FILE spectra data allows spectra as a function of damping as well as period. The format is: Data set 1 MDAMPCV NPOINTCV (no of values = 2) Data set 2 Damping Values in ascending order (no of values = Mdampcv) Data set 3a 3b Periods Spectra (no of values = Npointcv) (no of values = Npointcv) Repeat Data set 3 Mdampcv times (3a,3b , 3a,3b , 3a,3b , etc.) (i.e. for each damping value).
Section 5 5-299 5.32.10.1.1 Response Spectrum Specification in Conjunction with the Indian IS: 1893 (Part 1)-2002 Code for Dynamic Analysis Methodology The design lateral shear force at each floor in each mode is computed by STAAD in accordance with the Indian IS: 1893 (Part 1)-2002 equations 7.8.4.5c and 7.8.4.5d. Q ik = A k * φ ik *P k *W k and V ik = n ∑ Q ik i =i +1 Note: All symbols and notations in the above equation are as per IS: 1893(Part 1)-2002.
STAAD Commands and Input Instructions 5-300 Section 5 General Format: SPECTRUM {Method} 1893 (TOR) X f1 Y f2 Z f3 ACC (SCALE f4) (DAMP f5 or MDAMP or CDAMP) (MIS f6) (ZPA f7) SOIL TYPE f8 The data in the first line above must be on the first line of the command, the second line of data can be on the first or subsequent lines with all but last ending with a hyphen (limit of 3 lines ). The last line (Soil Type parameter) must be in a separate line.
Section 5 TOR indicates that the torsional moment (in the horizontal plane) arising due to eccentricity between the centre of mass and centre of rigidity needs to be considered. If TOR is entered on any one spectrum case it will be used for all spectrum cases. X Y Z f1, f2, f3 are the factors for the input spectrum to be applied in X, Y, & Z directions. These must be entered as the product of Z I * . Any one or all directions can be input. 2 R Directions not provided will default to zero.
STAAD Commands and Input Instructions 5-302 Section 5 parameter is entered on any spectrum case it will be used for all spectrum cases. ZPA f7 = For use with MIS option only. Defaults to 33 Hz if not entered. Value is printed but not used if MIS f6 is entered. SOIL TYPE f8 = the types of soil. f8 is 1 for rocky or hard soil, 2 for medium soil and 3 for soft soil sites. Depending upon time period, types of soil and damping, average response acceleration coefficient, Sa/g is calculated. Notes: 1.
Section 5 5-303 where, Sa = Spectrum ordinate ξ = damping ratio A, B = Constants The constants A and B are determined using two known spectrum ordinates Sa 1 & Sa 2 corresponding to damping ratios ξ 1 and ξ 2 respectively for a particular time period and are as follows : A = Sa 1ξ 1 − Sa 2 ξ 2 ξ 1e − ξ − ξ 2 e 1 −ξ 2 ξ 1ξ 2 (Sa 2 e − ξ − Sa 1e − ξ 1 B = ξ 1e −ξ1 − ξ 2e 2 ) −ξ 2 where, ξ 1 < ξ < ξ 2 3. The storey drift in any storey shall not exceed 0.
STAAD Commands and Input Instructions 5-304 Section 5 5.32.10.1.2 Response Spectrum Specification per Eurocode 8 Purpose This command may be used to specify and apply the RESPONSE SPECTRUM loading as per Eurocode 8 for dynamic analysis.
Section 5 algebraic summation of higher modes. ASCE & CQC are more sophisticated and realistic methods and are recommended. The specifier EURO is mandatory to denote that the applied loading is as per the guidelines of Eurocode 8. The response spectrum loading can be based on either ELASTIC or DESIGN response spectra.
STAAD Commands and Input Instructions 5-306 Section 5 DAMP , CDAMP , MDAMP. Select source of damping input. f4 = Damping ratio for all modes. Default value is 0.05 (5% damping if 0 or blank entered). DAMP indicates to use the f4 value for all modes. CDAMP indicates to use Composite modal damping if entered, otherwise same as MDAMP. MDAMP indicates to use the damping entered or computed with the DEFINE DAMP command if entered, otherwise default value of 0.05 will be used. LIN or LOG.
Section 5 Soil Type parameter is used to define the subsoil conditions based on which the response spectra will be generated. Based on the subsoil conditions the soil types may be of three kinds Type A : for Rock or stiff deposits of sand Type B :- for deep deposits of medium dense sand,gravel or medium stiff clays. Type C:- Loose cohesionless soil deposits or deposits with soft to medium stiff cohesive soil. Please refer section 3.2 of Eurocode 8 for detailed guidelines regarding the choice of soil type.
STAAD Commands and Input Instructions 5-308 Section 5 Description See Sections 1.18.3, 5.30, and 5.34 of STAAD Technical Reference Manual This command should appear as part of a loading specification. If it is the first occurrence, it should be accompanied by the load data to be used for frequency and mode shape calculations. Additional occurrences need no additional information. Maximum response spectrum load cases allowed in one run is 4.
Section 5 Multiple Response Spectra For special conditions more than one spectrum may be needed to adequately represent the seismic hazard over an area. This happens when the earthquake affecting the area are generated by sources varying widely in location and other parameters. In those cases different values of ALPHA as well as Q may be required to indicate the different shapes of response spectrum for each type of earthquake.
STAAD Commands and Input Instructions 5-310 Section 5 5.32.10.2 Application of Time Varying Load for Response History Analysis Purpose This set of commands may be used to model Time History loading on the structure for Response Time History analysis. Nodal time histories and ground motion time histories may both be provided under one load case. General format: TIME LOAD joint list See Sections 1.18.3, and 5.31.
Section 5 command to convert g’s to the acceleration units used in that command. This is recommended due to possible unit changes between that command and this command.] Multiple loads at a joint-direction pair for a particular ( I t I a ) pair will be summed. However there can only be one ( I t I a ) pair associated with a particular joint-direction pair, the first such entry will be used. Loads at slave joint directions will be moved to the master without moment generation.
STAAD Commands and Input Instructions 5-312 Section 5 In the above example, the permanent masses in the structure are provided in the form of "selfweight" and "member loads" (see sections 5.32 and 1.18.3) for obtaining the mode shapes and frequencies. The rest of the data is the input for application of the time varying loads on the structure. Forcing function type 1 is applied at joints 2 and 3 starting at arrival time number 3. (Arrival time number 3 is 1.8 seconds in example shown in section 5.31.4).
Section 5 5.32.11 Repeat Load Specification Purpose This command is used to create a primary load case using combinations of previously defined primary load cases. General format: REPEAT LOAD i 1 , f 1 , i 2 , f 2 ... i n , f n where, i 1 , i 2 ... i n = primary load case numbers f 1 , f 2 ... f n = corresponding factors This command can be continued to additional lines by ending all but last with a hyphen. Limit of 550 prior cases may be factored.
STAAD Commands and Input Instructions 5-314 Section 5 the REPEAT LOAD is used. 3) The REPEAT LOAD option is available with load cases with JOINT LOADS and MEMBER LOADS. It can also be used on load cases with ELEMENT PRESSURE loads and FIXED END LOADS. Modal dynamic analysis load cases (Response Spectrum, Time History, Steady State) should not be used in REPEAT LOAD. It is also not available for loads generated using some of the program’s load generation facilities such as MOVING LOAD Generation.
Section 5 Example LOAD 1 DL + LL SELFWEIGHT Y -1.4 MEMBER LOAD 1 TO 7 UNIFORM Y -3.5 LOAD 2 DL + LL + WL REPEAT LOAD 1 1.10 4) For a load case that is defined using the REPEAT LOAD attribute, the constituent load cases themselves can also be REPEAT LOAD cases. See load case 4 below. LOAD 1 SELFWEIGHT Y –1.0 LOAD 2 MEMBER LOAD 2 UNI GY –1.5 LOAD 3 REPEAT LOAD 1 1.5 LOAD 4 REPEAT LOAD 2 1.2 3 1.
STAAD Commands and Input Instructions 5-316 Section 5 5.32.12 Generation of Loads Purpose This command is used to generate Moving Loads, UBC Seismic loads and Wind Loads using previously specified load definitions. Primary load cases may be generated using previously defined load systems. The following sections describe generation of moving loads, UBC seismic loads and Wind Loads. Generation of Moving Loads See Sections 1.17 and 5.31.
Section 5 r = (Optional) defines section of the structure along global vertical direction to carry moving load. This r value is added and subtracted to the reference vertical coordinate (y 1 or z 1 )in the global vertical direction to form a range. The moving load will be externally distributed among all members within the vertical range thus generated. r always should be a positive number. In other words, the program always looks for members lying in the range Y 1 and Y 1 +ABS(r) or Z 1 and Z 1 +ABS(r).
STAAD Commands and Input Instructions 5-318 Section 5 modelled using plate elements, something which this facility cannot at present. 3. The x 1 , y 1 , z 1 values of the starting position of the reference wheel must be provided bearing in mind that the reference wheel has to be at the elevation of the deck. An improper set of values of these parameters may result in the wheels being positioned incorrectly, and consequently, no load may be generated at all.
Section 5 where i f1 = load case number = factor to be used to multiply the UBC Load (default = 1.0). May be negative. f2 = factor to be used to multiply the UBC, IBC, 1893, etc. Accidental torsion load (default = 1.0). May be negative. Use only horizontal directions. Example DEFINE UBC LOAD ZONE 0.2 K 1.0 I 1.5 TS 0.5 SELFWEIGHT JOINT WEIGHT 1 TO 100 WEIGHT 5.0 101 TO 200 WEIGHT 7.5 LOAD 1 UBC IN X-DIRECTION UBC LOAD X JOINT LOAD 5 25 30 FY -17.
STAAD Commands and Input Instructions 5-320 Section 5 UBC load case is not acceptable. Additional loads such as MEMBER LOADS and JOINT LOADS may be specified along with the UBC load under the same load case.
Section 5 Correct usage SET NL 10 LOAD 1 UBC LOAD X 1.2 JOINT LOAD 3 FY -4.5 PERFORM ANALYSIS CHANGE LOAD 2 UBC LOAD Z 1.2 MEMBER LOAD 3 UNI GY -4.
STAAD Commands and Input Instructions 5-322 Section 5 Incorrect usage LOAD 1 UBC LOAD X 1.2 SELFWEIGHT Y -1 JOINT LOAD 3 FY -4.5 PDELTA ANALYSIS LOAD 2 UBC LOAD Z 1.2 SELFWEIGHT Y -1 JOINT LOAD 3 FY -4.5 PDELTA ANALYSIS Correct usage LOAD 1 UBC LOAD X 1.2 SELFWEIGHT Y -1 JOINT LOAD 3 FY -4.5 PDELTA ANALYSIS CHANGE LOAD 2 UBC LOAD Z 1.2 SELFWEIGHT Y –1 JOINT LOAD 3 FY -4.
Section 5 4) REPEAT LOAD specification cannot be used for load cases involving UBC load generation unless each UBC case is followed by an analysis command then CHANGE. For example, Correct usage LOAD 1 UBC LOAD X 1.0 PDELTA ANALYSIS CHANGE LOAD 2 SELFWEIGHT Y -1 PDELTA ANALYSIS CHANGE LOAD 3 REPEAT LOAD 1 1.4 2 1.
STAAD Commands and Input Instructions 5-324 Section 5 Correct usage LOAD 1 UBC LOAD X 1.2 SELFWEIGHT Y -1 LOAD 2 UBC LOAD Z 1.2 SELFWEIGHT Y -1 PDELTA ANALYSIS Generation of IS:1893 Seismic Load See Sections 1.17.2 and 5.31.2.5 The following general format should be used to generate the IS 1893 load in a particular direction. General Format: LOAD i 1893 LOAD ⎧X ⎫ ⎨Y ⎬ ⎩Z ⎭ (f) where i = load case number f = factor to be used to multiply the 1893 Load (default = 1.0) Use only horizontal directions.
Section 5 Example DEFINE 1893 LOAD ZONE 0.05 RF 1.0 I 1.5 SS 1.0 SELFWEIGHT JOINT WEIGHT 7 TO 12 WEIGHT 17.5 13 TO 30 WEIGHT 18.0 MEMBER WEIGHT 1 TO 20 UNI 2.0 LOAD 1 1893 LOAD IN X-DIRECTION 1893 LOAD X JOINT LOAD 5 25 30 FY -17.5 LOAD 2 1893 LOAD IN Z-DIRECTION 1893 LOAD Z LOAD 3 DEAD LOAD SELFWEIGHT LOAD COMBINATION 4 1 0.75 2 0.75 3 1.0 In the above example, the first two load cases are the 1893 load cases. They are specified before any other load case.
STAAD Commands and Input Instructions 5-326 Section 5 General Format: LOAD WIND LOAD i ⎧ X ⎨ Y ⎩ Z ⎫ ⎧ ⎬ (f) TYPE j (OPEN)⎨ ⎪ ⎭ ⎪ XR YR ZR f1, f2 f1, f2 f1, f2 LIST memb-list ⎩ ALL See Sections 1.17.3 and 5.31.3 ⎫ ⎬ ⎪ ⎪ ⎭ Where i Load case number X, -X, Z or -Z, Y or -Y Direction of wind in global axis system. Use horizontal directions only. j Type number of previously defined systems f The factor to be used to multiply the wind loads.
Section 5 Y 5-327 Y X or Z X or Z X or Z +f -X or -Z Y +f Y X or Z X or Z -f X or Z -X or -Z -f Figure 5.38 A member list or a range of coordinate values (in global system) may be used. All members which have both end coordinates within the range are assumed to be candidates (for closed type structures) for defining a surface which may be loaded if the surface is exposed to the wind. The loading will be in the form of joint loads (not member loads).
STAAD Commands and Input Instructions 5-328 Section 5 WIND LOAD Z 1.2 TYPE 2 ZR 10 11 LOAD 3 WIND LOAD X TYPE 1 XR 7 8 ZR 14 16 LOAD 4 SUCTION ON LEEWARD SIDE WIND LOAD -X 1.2 LIST 21 22 42 Example for open structures LOAD 1 WIND LOAD IN Z DIRECTION WIND LOAD 2 -1.2 TYPE 1 OPEN Notes 1. For closed type structures, panels or closed surfaces are generated by the program based on the members in the rang es specified and their end joints.
Section 5 2. Plates and solids are not considered for wind load generation. On such entities, wind must be applied using pressure loading facilities for plates and solids. Figure 5.
STAAD Commands and Input Instructions 5-330 Section 5 5.32.13 Generation of Snow Loads Purpose This command is used to generate Snow Loads using previously specified Snow load definitions. This input should be a part of a load case. See Sections 1.16.9 and 5.31.5 General format: SNOW LOAD _flr_grp TYPE j CS f 1 ⎧ BALA ⎫ ⎧ OBST ⎫ ⎧ MONO ⎫ ⎨ ⎬ ⎨ ⎬ ⎨ HIP ⎬ ⎩ UNBA ⎭ ⎩ UNOB ⎭ ⎩ GABLE ⎭ where, _flr_grp = The members that form the roof and that are to be loaded by snow load must be listed in a floor group.
Section 5 5-331 5.33 Rayleigh Frequency Calculation Purpose This command may be used to calculate the Rayleigh method approximate frequency of the structure for vibration corresponding to the general direction of deflection generated by the load case that precedes this command. Thus, this command typically follows a load case. General format: CALCULATE RAYLEIGH (FREQUENCY) Description See Section 1.18.
STAAD Commands and Input Instructions 5-332 Section 5 In this example, the Rayleigh frequency for load case 1 will be calculated. The output will produce the value of the frequency in cycles per second (cps), the maximum deflection along with the global direction and the joint number where it occurs. Since the AREA LOAD is in the global Y direction, the displaced shape to be used as the mode will be in the Y direction.
Section 5 5-333 5.34 Modal Calculation Command Purpose This command may be used to obtain a full scale eigensolution to calculate relevant frequencies and mode shapes. It should not be entered if this case or any other case is a TIME LOAD or RESPONSE SPECTRUM case. For Steady State/Harmonic analysis this command must be included in the load case that defines the weights and weight moment of inertias for eigensolutions (see sections 1.18.3 and 5.32).
STAAD Commands and Input Instructions 5-334 Section 5 5.35 Load Combination Specification Purpose This command may be used to combine the results of the analysis. The combination may be algebraic, SRSS, a combination of both, or ABSolute. General format: LOAD COMBINATION i 1 , f 1 , i 2 , f 2 ... ⎧ SRSS ⎫ ⎨ ABS ⎬ i a 1 ⎩ ⎭ (f srss ) i = Load combination number ( any integer smaller than 100000 that is not the same as any previously defined primary load case number.
Section 5 2) 3) The total number of primary and combination load cases combined cannot exceed the limit described in section 5.2 of this manual. A value of zero (0) as a load factor is permitted. See Notes item (3) later in this section for more details.. Description LOAD COMBINATION Results from analyses will be combined algebraically. LOAD COMBINATION 6 DL+LL+WL 1 0.75 2 0.75 3 1.33 LOAD COMBINATION ABS Absolute value of results from the analyses will be combined. LOAD COMBINATION ABS 7 DL+LL+WL 1 0.
STAAD Commands and Input Instructions 5-336 Section 5 Simple SRSS Combination LOAD COMBINATION SRSS 8 DL+SEISMIC 1 1.0 2 -0.4 3 0.4 This (LOAD COMBINATION SRSS 8) illustrates a pure SRSS load combination with a default SRSS factor of 1. The following combination scheme will be used v= 1.0 1 x L1 2 - 0.4 x L2 2 + 0.4 x L3 2 where v = the combined value and L1 - L3 = values from load cases 1,2 and 3. Since an SRSS factor is not provided, the default value of 1.0 is being used.
Section 5 Example 2 LOAD COMBINATION SRSS 10 -1 0.75 -2 0.572 3 1.2 4 1.7 0.63 Here, both load cases 1 and 2 are combined algebraically with the SRSS combination of load cases 3 and 4. Note the SRSS factor of 0.63. The combination formula will be as follows. v = 0.75 x L1 + 0.572 x L2 + 0.63 1.2 x L3 2 + 1.7 x L4 2 Notes 1) This option combines the results of the analysis in the specified manner. It does not analyze the structure for the combined loading.
STAAD Commands and Input Instructions 5-338 Section 5 4) All combination load cases must be provided immediately after the last primary load case. 5) The maximum number of load cases that can be combined using a LOAD COMBINATION command is 550.
Section 5 5.36 Calculation of Problem Statistics Removed. Please contact the Technical Support division for more details.
STAAD Commands and Input Instructions 5-340 Section 5 5.37 Analysis Specification Purpose STAAD analysis options include linear static analysis, P-Delta (or second order analysis), and several types of Dynamic analysis. This command is used to specify the analysis request. In addition, this command may be used to request that various analysis related data, like load info, statics check info, etc. be printed.
Section 5 5-341 g) If a RESPONSE SPECTRUM or TIME LOAD is specified within a load case or the MODAL CALCULATION command is used, a dynamic analysis is performed. h) In each of the "n" iterations of the PDELTA analysis, the load vector will be modified to include the secondary effect generated by the displacements caused by the previous analysis. There are two options to carry out P-Delta analysis. 1) When the CONVERGE command is not specified: The member end forces are evaluated by iterating “n” times.
STAAD Commands and Input Instructions 5-342 Section 5 Without one of these analysis commands, no analysis will be performed. These ANALYSIS commands can be repeated if multiple analyses are needed at different phases. A PDELTA ANALYSIS will correctly reflect the secondary effects of a combination of load cases only if they are defined using the REPEAT LOAD specification (Section 5.32.11). Secondary effects will not be evaluated correctly for LOAD COMBINATIONS.
Section 5 ⎧ ⎫ ⎨ PERFORM CABLE ⎬ ANALYSIS ⎩ ⎭ ⎧STEPS ⎪EQITERATIONS ( ⎨EQTOLERANCE ⎪SAGMINIMUM ⎪STABILITY f5 ⎩KSMALL f1 f2 f3 f4 f6 f7 5-343 ⎫ ⎪ ⎬) ⎪ ⎪ ⎭ This command may be continued to the next line by ending with a hyphen. Steps = Number of load steps. The applied loads will be applied gradually in this many steps. Each step will be iterated to convergence. Default is 145. The f1 value, if entered, should be in the range 5 to 145.
STAAD Commands and Input Instructions 5-344 Section 5 This parameter alters the stiffness of the structure. K small stiffness = A stiffness matrix value, f7, that is added to the global matrix at each translational direction for joints connected to cables and nonlinear trusses for every load step. If entered, use 0.0 to 1.0. Default is 0.0 . This parameter alters the stiffness of the structure. Notes STAAD allows multiple analyses in the same run.
Section 5 5-345 5) PDELTA effects are computed for frame members and plate elements only. They are not calculated for solid elements. 6) Analysis and CHANGE are required between primary cases for PERFORM CABLE ANALYSIS. 7) Analysis and CHANGE are required after UBC cases if the case is subsequently referred to in a Repeat Load command or if the UBC case will be re-solved after a Select command or after a Multiple analysis.
STAAD Commands and Input Instructions 5-346 Section 5 5.37.1 Steady State & Harmonic Analysis The options available under steady state analysis in STAAD are described in the next few sections.
Section 5 5.37.1.1 Purpose This analysis type is used to model steady, harmonically varying load on a structure to solve for the steady harmonic response after the initial transient response has damped out to zero. STAAD Steady State analysis options include results for one forcing frequency or for a set of frequencies. You may specify ground motion or a distributed joint loading in one load case. Damping is required either in this input or from the Modal Damp input or from the Composite Damping input.
STAAD Commands and Input Instructions 5-348 Section 5 This command directs the program to perform the analysis that includes: a) b) c) e) f) Checking whether all information is provided for the analysis; Forming the joint stiffness matrix; Solving simultaneous equations; Solving for modes and frequencies; Computing for the steady state joint displacements, velocities & accelerations and phase angles; g) Computing the above quantities versus frequency and displaying the results graphically.
Section 5 In PRINT JOINT DISP and in Post processor displayed results, the load case displacement for a given joint and direction will be the maximum value over all of the frequencies (without the phase angles) for a Steady State load case. In post-processing for harmonic analysis, Log-Log graphs of any joint’s relative translational displacement or velocity or acceleration versus frequency may be selected. See section 5.37.1.8 for printing displacements with phase angles by frequency.
STAAD Commands and Input Instructions 5-350 Section 5 5.37.1.2 Define Harmonic Output Frequencies If Harmonic is requested above, then optionally include the next input. FREQUENCY FLO f 1 FHI f 2 NPTS f 3 (MODAL) FLIST freqs FLO f 1 = Lowest frequency to be included in Harmonic output. Default to half the first natural frequency. FHI f 2 = Highest frequency to be included in Harmonic output. Default to highest frequency plus largest difference between two consecutive natural frequencies.
Section 5 5.37.1.3 Define Load Case Number Currently the load case number is automatically the case with the MODAL CALC command.
STAAD Commands and Input Instructions 5-352 Section 5 5.37.1.4 Steady Ground Motion Loading This set of commands may be used to specify steady ground motion loading on the structure, the ground motion frequency, the modal damping, and the phase relationship of ground motions in each of the global directions. General format: STEADY GROUND FREQ f 1 ⎧ DAMP f2 ⎫ ⎨ CDAMP ⎬ ⎩ MDAMP ⎭ ⎧ ABS ⎫ ⎨ ⎬ ⎩ REL ⎭ This command specifies the ground motion frequency and damping. FREQ.
Section 5 General format: GROUND MOTION ⎧X ⎫ ⎨Y ⎬ ⎩Z ⎭ ⎧ ⎫ ⎨ACCEL ⎬ f3 PHASE f4 ⎩DISP ⎭ Enter the direction of the ground motion, the acceleration magnitude, and the phase angle by which the motion in this direction lags (in degrees). One Ground Motion command can be entered for each global direction. f 3 Ground acceleration in g’s or displacement in length units.
STAAD Commands and Input Instructions 5-354 Section 5 5.37.1.5 Steady Force Loading This set of commands may be used to specify JOINT loads on the structure, the forcing frequency, the modal damping, and the phase relationship of loads in each of the global directions. General format: STEADY FORCE FREQ f 1 ⎧ DAMP f2 ⎫ ⎨ CDAMP ⎬ ⎩ MDAMP ⎭ This command specifies the forcing frequency and damping for a case of steady forces. FREQ.
Section 5 5-355 phase angle of 0.0. All forces specified below will be applied with the phase angle specified above, if any. Default is 0.0. f 7 Phase angle in degrees. One phase angle per global direction. Next are the joint forces, if any. Repeat this command as many times as needed. joint-list * ⎧FX ⎪FY ⎨FZ ⎪MX ⎪MY ⎩MZ f1 ⎫ f2 ⎪ f3 ⎬ f4 ⎪ f5 ⎪ f6 ⎭ FX, FY and FZ specify a force in the corresponding global direction. MX, MY and MZ specify a moment in the corresponding global direction. f 1 , f 2 ..
STAAD Commands and Input Instructions 5-356 Section 5 General format: COPY LOAD i 1 , f 1 , i 2 , f 2 ... i n , f n where, i 1 , i 2 ... i n = prior primary load case numbers that are in this analysis set. f 1 , f 2 ... f n = corresponding factors This command can be continued to additional lines by ending all but last with a hyphen. These cases must have been between the Perform Steady State Analysis command and the prior Analysis command (if any).
Section 5 5-357 5.37.1.6 Harmonic Ground Motion Loading This set of commands may be used to specify harmonic ground motion loading on the structure, the modal damping, and the phase relationship of ground motions in each of the global directions. Response at all of the frequencies defined in section 5.37.1.2 will be calculated. General format: HARMONIC GROUND ⎧ DAMP f2 ⎫ ⎨ CDAMP ⎬ ⎩ MDAMP ⎭ ⎧ ABS ⎫ ⎨ ⎬ ⎩ REL ⎭ This command specifies the damping.
STAAD Commands and Input Instructions 5-358 Section 5 General format: GROUND MOTION ⎧X ⎫ ⎨Y ⎬ ⎩Z ⎭ ⎧ ⎫ ⎨ACCEL ⎬ f3 PHASE f4 ⎩DISP ⎭ Enter the direction of the ground motion, the acceleration and the phase angle by which the motion in this direction lags (in degrees). One Ground Motion command can be entered for each global direction. f 3 Ground acceleration in g’s or displacement in length units.
Section 5 5-359 Frequency - Amplitude pairs are entered to describe the variation of acceleration with frequency. Continue this data onto as many lines as needed by ending each line except the last with a hyphen (-). These pairs must be in ascending order of frequency. Use up to 199 pairs. Linear interpolation is used. One Ground Motion and Amplitude command set can be entered for each global direction.
STAAD Commands and Input Instructions 5-360 Section 5 5.37.1.7 Harmonic Force Loading This set of commands may be used to specify JOINT loads on the structure, the modal damping, and the phase relationship of loads in each of the global directions. Response at all of the frequencies defined in section 5.37.1.2 will be calculated. General format: HARMONIC FORCE ⎧ DAMP f2 ⎫ ⎨ CDAMP ⎬ ⎩ MDAMP ⎭ This command specifies the damping for a case of harmonic forces. DAMP , MDAMP and CDAMP.
Section 5 f 7 Phase angle in degrees. One phase angle per direction. Next are the joint forces, if any. Repeat this command as many times as needed. joint-list * ⎧FX ⎪FY ⎨FZ ⎪MX ⎪MY ⎩MZ f1 ⎫ f2 ⎪ f3 ⎬ f4 ⎪ f5 ⎪ f6 ⎭ FX, FY and FZ specify a force in the corresponding global direction. MX, MY and MZ specify a moment in the corresponding global direction. f 1 , f 2 ... f 6 are the values of the loads. Notes • • Joint numbers may be repeated where loads are meant to be additive in the joint.
STAAD Commands and Input Instructions 5-362 Section 5 f 1 , f 2 ... f n = corresponding factors This command can be continued to additional lines by ending all but last with a hyphen. These cases must have been between the Perform Steady State Analysis command and the prior Analysis command (if any). Next is an optional force multiplier (amplitude) versus frequency specification to be used when the force loading is a function of frequency.
Section 5 Frequency - Amplitude pairs are entered to describe the variation of the force multiplier (amplitude) with frequency. Continue this data onto as many lines as needed by ending each line except the last with a hyphen (-). These pairs must be in ascending order of frequency. Use up to 199 pairs. Linear interpolation is used. Enter amplitudes for up to 3 directions. For directions without amplitude input, including moment directions, the amplitude will be set to 1.0.
STAAD Commands and Input Instructions 5-364 Section 5 5.37.1.8 Print Steady State/Harmonic Results PRINT HARMONIC DISPLACEMENTS List-spec = List- spec ⎧(ALL) ⎨LIST list of items-joints ⎩ ⎫ ⎬ ⎭ This command must be after all steady state/harmonic loadings and before the END STEADY command. For each harmonic frequency of section 5.37.1.2 the following will be printed: 1. Modal responses. 2. Phase angles with 1 line per selected joint containing the phase angle for each of the 6 directions of motion.
Section 5 3 5 5 4 10 6 35 3 GROUND MOTION Z ACC .15 PHASE 20.0 AMPLIT A 0.10 B .21 C 0.03 PRINT HARMONIC DISP ALL END BEGIN STEADY FORCE STEADY FORCE FREQ 11.2 DAMP .033 JOINT LOAD PHASE X 0.0 PHASE Y 10.0 PHASE Z 15.0 UNIT KIP 10 5 TO 7 BY 2 88 FX 10.0 FY 5.0 UNIT POUND 10 5 TO 7 BY 2 88 FX 10.0 FY 5.0 COPY LOAD 1 1.5 2 0.8 3 1.0 PRINT HARMONIC DISP ALL END BEGIN HARMONIC FORCE FREQ FLO 3.5 FHI 33 NPTS 5 MODAL FLIST 4 5 10 17 21 30 HARMONIC FORCE DAMP .033 JOINT LOAD PHASE X 0.0 PHASE Y 10.0 PHASE Z 15.
STAAD Commands and Input Instructions 5-366 Section 5 BEGIN HARMONIC FORCE FREQ FLO 3.5 FHI 33 NPTS 5 MODAL FLIST 4 5 10 17 21 30 HARMONIC FORCE DAMP .033 JOINT LOAD PHASE X 0.0 PHASE Y 10.0 PHASE Z 15.0 UNIT KIP 10 5 TO 7 BY 2 88 FX 10.0 FY 5.0 UNIT POUND 10 5 TO 7 BY 2 88 FX 10.0 FY 5.0 COPY LOAD 1 1.5 2 0.8 3 1.0 AMPLIT ALL A 0.10 B .
Section 5 5.37.1.
STAAD Commands and Input Instructions 5-368 Section 5 5.38 Change Specification Purpose This command is used to reset the stiffness matrix. Typically, this command is used when multiple analyses are required in the same run. General format: CHANGE This command indicates that input, which will change the stiffness matrix, will follow. This command should only be used when an analysis has already been performed.
Section 5 5-369 g) Analysis and CHANGE are required between primary cases for PERFORM CABLE ANALYSIS. h) Analysis and CHANGE are required after each UBC case if the case is subsequently referred to in a Repeat Load command or if the UBC case will be re-solved after a Select command or after a Multiple analysis. Example Before CHANGE 1 PINNED 2 FIXED BUT FX MY MZ 3 FIXED BUT FX MX MY MZ After CHANGE 1 PINNED 2 FIXED 3 FIXED BUT FX MZ See Section 5.
STAAD Commands and Input Instructions 5-370 Section 5 3) Section forces and moments, stress and other results for postprocessing will use the last entered data for supports and member properties regardless of what was used to compute the displacements, end forces and reactions. So beware of changing member properties and releases after a CHANGE command.
Section 5 5.39 Load List Specification Purpose This command allows specification of a set of active load cases. All load cases made active by this command remain active until a new load list is specified. General format: LOAD LIST ⎧load-list ⎫ ⎨ ⎬ ⎩ALL ⎭ Description This command is used to activate the load cases listed in this command and, in a sense, deactivate all other load cases not listed in this command.
STAAD Commands and Input Instructions 5-372 Section 5 In this example, member forces will be printed for all load cases, whereas loading 1 and 3 will be used for printing support reactions and code-checking of all members. Notes The LOAD LIST command may be used for multiple analyses situations when a re-analysis needs to be performed with a selected set of load cases only. All load cases are automatically active before the first CHANGE command is used.
Section 5 5-373 5.40 Section Specification Purpose This command is used to specify intermediate sections along the length of frame member for which forces and moments are required. General format: SECTION f1, f2 ... f3 ⎧MEMBER memb-list ⎫ ⎨ ⎬ ⎩( ALL ) ⎭ Description This command specifies the sections, in terms of fractional member lengths, at which the forces and moments are considered for further processing. See Sections 1.19.2,and 1.19.4 f 1 , f 2 ...
STAAD Commands and Input Instructions 5-374 Section 5 them. As mentioned earlier, no more than three intermediate sections are allowed per SECTION command. However, if more than three intermediate sections are desired, they can be examined by repeating the SECTION command after completing the required calculations. The following example will clarify. Example SECTION 0.2 0.4 0.5 ALL PRINT SECTION FORCES SECTION 0.6 0.75 0.
Section 5 5-375 5.41 Print Specifications Purpose This command is used to direct the program to print various modeling information and analysis results. STAAD offers a number of versatile print commands that can be used to customize the output. General format for data related print commands: PRINT ⎧JOINT COORDINATES ⎪MEMBER INFORMATION ⎪ELEMENT INFORMATION (SOLID) ⎪ MEMBER PROPERTIES ⎨ MATERIAL PROPERTIES ⎪SUPPORT INFORMATION ⎪or ⎩ALL ⎫ ⎪ ⎪ ⎪ ⎬ ⎪ ⎪ ⎭ ⎧(ALL) ⎫ ⎪ ⎪ ⎨ LIST list of items ⎬ ⎪ i.e.
STAAD Commands and Input Instructions 5-376 Section 5 General format to print support reactions: PRINT SUPPORT REACTIONS General format to print story drifts: PRINT STORY DRIFT Description The list of items is not applicable for PRINT ANALYSIS RESULTS and PRINT MODE SHAPES commands. The PRINT JOINT COORDINATES command prints all interpreted coordinates of joints.
Section 5 The following designation is used for member property names: AX AY - AZ - IZ IY IX SY SZ - Cross section area Area used to adjust shear/bending stiffness in local Y axis to account for pure shear in addition to the classical bending stiffness. Area used to adjust shear/bending stiffness in local Z axis to account for pure shear in addition to the classical bending stiffness.
STAAD Commands and Input Instructions 5-378 Section 5 group-names). Only the selfweight of the structure is used to calculate the C.G. User defined joint loads, member loads etc. are not considered in the calculation of C.G. The PRINT (JOINT) DISPLACEMENTS command prints joint displacements in a tabulated form. The displacements for all six global directions will be printed for all specified load cases.
Section 5 5-379 (absolute combination of axial, bending-y and bending-z) stresses. For PRISMATIC sections, if AY and/or AZ is not provided, the full cross-sectional area (AX) will be used. For TAPERED sections, the values of AY and AZ are those for the location where the stress is printed. Hence at the location 0.0, the AY and AZ are based on the dimensions of the member at the start node.
STAAD Commands and Input Instructions 5-380 Section 5 ANGLE = Angle which determines direction of maximum principal stress with respect to local X axis If the JOINT option is used, forces and moments at the nodal points are also printed out in addition to the centroid of the element. The AT option may be used to print element forces at any specified point within the element. The AT option must be accompanied by f 1 and f 2 .
Section 5 The PRINT STORY DRIFT command may be used to obtain a print-out of the average lateral displacement of all joints at each horizontal level along the height of the structure. Example PERFORM ANALYSIS PRINT ELEMENT JOINT STRESS PRINT ELEMENT STRESS AT 0.5 0.5 LIST 1 TO 10 PRINT SUPPORT REACTIONS PRINT JOINT DISPLACEMENTS LIST 1 TO 50 PRINT MEMBER FORCES LIST 101 TO 124 Notes 1) The output generated by these commands is based on the current unit system.
STAAD Commands and Input Instructions 5-382 Section 5 5.42 Stress/Force output printing for Surface Entities Default locations for stress/force output, design, and design output for surface elements are set as follows: SURFACE DIVISION X xd SURFACE DIVISION Y yd where: xd - number of divisions along X axis, yd - number of divisions along Y axis. xd and yd represent default numbers of divisions for each edge of the surface where output is requested.
Section 5 d1, d2 - coordinates in the direction orthogonal to ξ, delineating a fragment of the full crosssection for which the output is desired. s1, ...,si - list of surfaces for output generation Note: If the keyword ALONG is omitted, direction Y (default) is assumed. If command AT is omitted, output is provided for all sections along the specified (or default) edge. Number of sections will be determined from the SURFACE DIVISION X or SURFACE DIVISION Y input values.
STAAD Commands and Input Instructions 5-384 Section 5 5.43 Printing Section Displacements for Members Purpose This command is used to calculate and print displacements at sections (intermediate points) of frame members. This provides the user with deflection data between the joints. General format: PRINT SECTION (MAX) DISPL (NSECT i) (SAVE a) ⎧NOPRINT ⎨ALL ⎩LIST memb-list ⎫ ⎬ ⎭ Description Y Original Position y-displ. x-displ.
Section 5 5-385 Example PRINT SECTION DISPL SAVE PRINT SECTION MAX DISP See Section 1.19.3 SECTION DISPLACEMENTS are measured in GLOBAL COORDINATES. The values are measured from the original (undeflected) position to the deflected position. See figure above. The maximum local displacement is also printed. First, the location is determined and then the value is measured from this location to the line joining start and end joints of the deflected member. Local Deflection Figure 5.
STAAD Commands and Input Instructions 5-386 Section 5 5.44 Printing the Force Envelope Purpose This command is used to calculate and print force/moment envelopes for frame members. This command is not available for finite elements. General format: PRINT ⎧FORCE ⎫ ⎨ ⎬ ⎩MAXFORCE ⎭ list-spec = ENVELOPE (NSECTION i) list-sp. ⎧LIST memb-list ⎫ ⎨ ⎬ ⎩(ALL) ⎭ Description See Section 1.19.
Section 5 Example PRINT FORCE ENV PRINT MAXF ENV NS 15 PRINT FORCE ENV NS 4 LIST 3 TO 15 Notes This is a secondary analysis command and should be used after analysis specification.
STAAD Commands and Input Instructions 5-388 Section 5 5.45 Post Analysis Printer Plot Specifications Purpose This command has been discontinued in STAAD.Pro. Please use the facilities of the Graphical User Interface (GUI) for screen and hard copy graphics.
Section 5 5-389 5.46 Size Specification Purpose This command provides an estimate for required section properties for a frame member based on certain analysis results and user requirements. General Format: * SIZE ⎧WIDTH ⎪DEFLECTION ⎨LENGTH ⎪BSTRESS ⎩SSTRESS f1 ⎫ f2 ⎪ f3 ⎬ f4 ⎪ f5 ⎭ ⎧ MEMBER member-list ⎫ ⎨ ⎬ ⎩ ALL ⎭ where, f 1 = Maxm. allowable width f 2 = Maxm. allowable (Length/Maxm. local deflection) ratio f 3 = Length for calculating the above ratio. Default = actual member length. f 4 = Maxm.
STAAD Commands and Input Instructions 5-390 Section 5 Example SIZE WID 12 DEFL 300 LEN 240 BSTR 36 ALL SIZE DEFL 450 BSTR 42 MEMB 16 TO 25 Note: It may be noted that sizing will be based on only the criteria specified by the user in the relevant SIZE command. In the first example above, sizing will be based on user specified member width of 12, Length/Deflection ratio of 300 (where Length= 240) and max. allowable bending stress of 36.
Section 5 5-391 5.47 Steel and Aluminum Design Specifications This section describes the specifications necessary for structural steel & aluminum design.
STAAD Commands and Input Instructions 5-392 Section 5 5.47.1 Parameter Specifications Purpose This set of commands may be used to specify the parameters required for steel and aluminum design.
Section 5 Description Parameter-name refers to the "PARAMETER NAME" (s) listed in the parameter table contained in the Steel and Aluminum Design section. f 1 = Value of the parameter.
STAAD Commands and Input Instructions 5-394 Section 5 Example PARAMETERS CODE AISC KY 1.5 MEMB 3 7 TO 11 NSF 0.75 ALL PROFILE W12 W14 MEMB 1 2 23 RATIO 0.9 ALL Notes 1) All unit sensitive values should be in the current unit system. 2) For default values of the parameters, refer to the appropriate parameter table.
Section 5 5-395 5.47.2 Code Checking Specification Purpose This command may be used to perform the CODE CHECKING operation for steel and aluminum members. General format: CHECK CODE ⎧MEMBER memb-list ⎨ ⎩ALL ⎩membergroupname ⎩deckname ⎫ ⎬ ⎭ ⎭ ⎭ Description This command checks the specified members against the specification of the desired code. Refer to Section 2 of this manual for detailed information. See Section 2.5 Notes The output of this command may be controlled using the TRACK parameter.
STAAD Commands and Input Instructions 5-396 Section 5 5.47.3 Member Selection Specification Purpose This command may be used to perform the MEMBER SELECTION operation. General format: SELECT ⎧MEMBER memb-list ⎨ ⎩ALL ⎩membergroupname ⎩deckname ⎫ ⎬ ⎭ ⎭ ⎭ Description This command instructs STAAD to select specified members based on the parameter value restrictions and specified code.
Section 5 2) Member selection can be done only after an analysis has been performed. Consequently, the command to perform the analysis has to be specified before the SELECT MEMBER command can be specified. 3) This command does not cause the program to re-analyze for results based on the selected member sizes. However, to maintain compatibility of analysis results with the final member sizes, you should enter a subsequent PERFORM ANALYSIS command.
STAAD Commands and Input Instructions 5-398 Section 5 5.47.4 Member Selection by Optimization Purpose This command performs member selection using an optimization technique based on multiple analysis/design iterations. General format: SELECT OPTIMIZED Description The program selects all members based on an optimization technique. This method performs 2 analyses as well as iteration of sizes to reduce the overall structure weight.
Section 5 5-399 5.47.5 Weld Selection Specification Purpose This command performs selection of weld sizes for specified members. General format: SELECT WELD (TRUSS) ⎧MEMBER memb-list ⎫ ⎨ ⎬ ⎩ALL ⎭ Description By this command, the program selects the weld sizes of the specified members at start and end. The selections are tabulated with all the necessary information.
STAAD Commands and Input Instructions 5-400 Section 5 5.48 Group Specification Purpose This command may be used to group members together for analysis and steel design. General format: (FIXED GROUP) GROUP prop-spec MEMB memb-list (SAME AS i 1 ) prop-spec = ⎧AX ⎫ ⎨SY ⎬ ⎩SZ ⎭ = Cross-section area = Section modulus in local y-axis = Section modulus in local z-axis Description This command enables the program to group specified members together for analysis based on their largest property specification.
Section 5 Example 1 SELECT ALL GROUP SZ MEMB 1 3 7 TO 12 15 GROUP MEMB 17 TO 23 27 SAME AS 30 In this example, the members 1, 3, 7 to 12, and 15 are assigned the same properties based on which of these members has the largest section modulus. Members 17 to 23 and 27 are assigned the same properties as member 30, regardless of whether member 30 has a smaller or larger cross-sectional area. AX is the default property upon which grouping is based.
STAAD Commands and Input Instructions 5-402 Section 5 Notes The FIXED GROUP + GROUP commands are typically entered before the member selection for further analysis and design. This facility may be effectively utilized to develop a practically oriented design where several members need to be of the same size. All the members in a list for a specific GROUP command should have the same cross section type.
Section 5 5.49 Steel Take Off Specification Purpose This command may be used to obtain a summary of all steel sections being used along with their lengths and weights. General format: ⎧LIST memb-list STEEL (MEMBER) TAKE ( OFF ) ( ⎫ ⎨LIST membergroupname⎬) ⎭ ⎩ALL Description This command provides a listing of the different steel table sections used in the members selected. The tabulated listing will include total length of each section name and its total weight.
STAAD Commands and Input Instructions 5-404 Section 5 5.50 Timber Design Specifications This section describes the specifications required for timber design. Detailed description of the timber design procedures is available in Section 4. Section 5.50.1 describes specification of parameters for timber design. Sections 5.50.2 and 5.50.3 discusses the code checking and member selection facilities respectively.
Section 5 5.50.1 Timber Design Parameter Specifications Purpose This set of commands may be used for specification of parameters for timber design. General Format: PARAMETER CODE TIMBER parameter-name f 1 ⎧ MEMBER member-list ⎫ ⎨ ⎬ ⎩ ALL ⎭ Description f 1 = the value of the parameter. The parameter-name refers to the parameters described in Section 4. Notes 1) All values must be provided in the current unit system. 2) For default values of parameters, refer to Section 4.
STAAD Commands and Input Instructions 5-406 Section 5 5.50.2 Code Checking Specification Purpose This command performs code checking operation on specified members based on the American Institute of Timber Construction (AITC) codes. General Format: CHECK CODE ⎧ MEMBER member-list ⎫ ⎨ ⎬ ⎩ ALL ⎭ Description This command checks the specified members against the requirements of the American Institute of Timber Construction (AITC) codes. The results of the code checking are summarized in a tabular format.
Section 5 5.50.3 Member Selection Specification Purpose This command performs member selection operation on specified members based on the American Institute of Timber Construction (AITC) codes. General Format: SELECT ⎧ MEMBER member-list ⎫ ⎨ ⎬ ⎩ ALL ⎭ Description This command may be used to perform member selection according to the AITC codes.
STAAD Commands and Input Instructions 5-408 Section 5 5.51 Concrete Design Specifications for beams, columns and plate elements This section describes the specifications for concrete design for beams, columns and individual plate elements. The concrete design procedure implemented in STAAD consists of the following steps: 1) 2) 3) 4) 5) Initiating the design. Specifying parameters. Specifying design requirements. Requesting quantity take-off. Terminating the design. Section 5.51.
Section 5 5.51.1 Design Initiation Purpose This command is used to initiate concrete design for beams, columns and individual plate elements. General format: START CONCRETE DESIGN Description This command initiates the concrete design specification. With this, the design parameters are automatically set to the default values (as shown on Table 3.1). Without this command, none of the following concrete design commands will be recognized.
STAAD Commands and Input Instructions 5-410 Section 5 5.51.2 Concrete Design-Parameter Specification Purpose This set of commands may be used to specify parameters to control concrete design for beams, columns and individual plate elements.
Section 5 5-411 Notes 1) All parameter values are provided in the current unit system. 2) For default values of parameters, refer to Section 3 for the ACI code. For other codes, please see the International Codes manual.
STAAD Commands and Input Instructions 5-412 Section 5 5.51.3 Concrete Design Command Purpose This command may be used to specify the type of design required. Members may be designed as BEAM, COLUMN or ELEMENT. General format: DESIGN ⎧BEAM ⎫ ⎨COLUMN ⎬ ⎧ memb-list ⎫ ⎩ELEMENT ⎭ ⎩( ALL ) ⎭ Description Members to be designed must be specified as BEAM, COLUMN or ELEMENT. Members, once designed as a beam, cannot be redesigned as a column again, or vice versa.
Section 5 5.51.4 Concrete Take Off Command Purpose This command may be used to obtain an estimate of the total volume of the concrete, reinforcement bars used and their respective weights. General Format: CONCRETE TAKE OFF Description This command can be issued to print the total volume of concrete and the bar numbers and their respective weight for the members designed.
STAAD Commands and Input Instructions 5-414 Section 5 5.51.5 Concrete Design Terminator Purpose This command must be used to terminate the concrete design. General format: END CONCRETE DESIGN Description This command terminates the concrete design, after which normal STAAD commands resume. Example START CONCRETE DESIGN CODE ACI FYMAIN 40.0 ALL FC 3.0 ALL DESIGN BEAM 1 TO 4 7 DESIGN COLUMN 9 12 TO 16 DESIGN ELEMENT 20 TO 30 END Notes Without this command, further STAAD commands will not be recognized.
Section 5 5-415 5.52 Footing Design Specifications Purpose This set of commands may be used to specify footing design requirements. Sections 5.52.1 through 5.52.4 describe the process of design initiation, parameter specification, design command and design termination. Description This facility may be used to design isolated footings for user specified support joints. Once the support is specified, the program automatically identifies the support reaction(s) associated with the joint.
STAAD Commands and Input Instructions 5-416 Section 5 Design Procedure The following sequential design procedure is followed: 1) Footing size is calculated on the basis of the load directly available from the analysis results (support reactions) and user specified Allowable Soil Pressure. No factor is used on the support reactions. 2) The footing size obtained from 1) and the FACTORED LOAD is utilized to calculate soil reactions.
Section 5 Design Parameters Cont. Parameter Name Default Value Description TRACK 1.0 1.0 = only numerical output is provided 2.0 = numerical output and sketch provided DEPTH Calculated by the program The min. depth of the footing base slab. Program changes this value if required for design. S1, S2 Calculated by the program Size of the footing base slab S1 and S2 correspond to column sides YD and ZD respectively. Either S1 or S2 or both can be specified.
STAAD Commands and Input Instructions 5-418 Section 5 5.52.1 Design Initiation Purpose This command must be used to initiate the footing design. General Format: START FOOTING DESIGN Description This command initiates the footing design specifications. Without this command, no further footing design command will be recognized. Notes No footing design specification will be processed without this command.
Section 5 5.52.2 Footing Design Parameter Specification Purpose This command is used to specify parameters that may be used to control the footing design. General Format: CODE AMERICAN parameter-name f 1 ⎧JOINT joint-list ⎫ ⎨ ⎬ ⎩( ALL ) ⎭ Description Parameter-name refers to the parameters described in Section 5.52. f 1 is the value of the parameter. If applicable, this value should be in the current units. The UNIT command is also accepted during any phase of footing design.
STAAD Commands and Input Instructions 5-420 Section 5 5.52.3 Footing Design Command Purpose This command must be used to execute the footing design. General Format: DESIGN FOOTING ⎧ joint-list ⎩( ALL ) ⎫ ⎭ Description This command may be used to specify the joints for which the footing designs are required. Notes The output of this command may be controlled by the TRACK parameter (see Section 5.52). If TRACK is set to the default value of 1.0, only numerical output will be provided.
Section 5 EXAMPLE START FOOTING DESIGN CODE AMERICAN UNIT . . . FY 45.0 JOINT 2 FY 60.0 JOINT 5 FC 3 ALL RATIO 0.8 ALL TRACK 2.0 ALL PEDESTAL 1.0 ALL UNIT . . . CLEAR 0.25 BC 5.20 JOINT 2 BC 5.
STAAD Commands and Input Instructions 5-422 Section 5 5.52.4 Footing Design Terminator Purpose This command must be used to terminate the footing design. General Format: END FOOTING DESIGN Description This command terminates the footing design. Notes If the footing design is not terminated, no further STAAD command will be recognized.
Section 5 5-423 5.53 Shear Wall Design Purpose STAAD performs design of reinforced concrete shear walls per two codes currently: ACI 318-02 and BS 8110. In order to design a shear wall, it must first be modelled using the Surface element. The attributes associated with surfaces, and the sections of this manual where the information may be obtained, are listed below: Attributes Related Sections Surfaces incidences - 5.13.3 Openings in surfaces - 5.13.3 Local coordinate system for surfaces - 1.6.
STAAD Commands and Input Instructions 5-424 Section 5 b. Panels have been defined. Design is performed for all panels, for the cross-section located at a distance c from the start of the panel. Shear Wall design is currently not available for dynamic load cases.
Section 5 5.53.1 Definition of Wall Panels for Shear Wall Design Due to the presence of openings, three types of structural elements may be defined within the boundaries of a shear wall: wall, column, and beam. For each of those entities, a different set of design and detailing rules applies. Users assign those types to panels - functionally different parts of the shear wall. The assignment is based on panel geometry, its position, and overall wall configuration.
STAAD Commands and Input Instructions 5-426 Section 5 5.53.2 Shear Wall Design Initiation General format: START SHEARWALL DESIGN CODE a parameters DESIGN SHEARWALL (AT c) LIST s CREINF cr TRACK tr END SHEARWALL DESIGN where: a - code name – ACI (for ACI 318), BRITISH (for BS 8110) parameters - these are listed in a tabular form in section 3.8.2 of this manual for the ACI code, and in the International Codes manual for BS 8110. cr - column reinforcing parameter, tr - output parameter.
Section 5 Parameter TRACK specifies how detailed the design output should be: 0 - indicates a basic set of results data (default), 1 - full design output will be generated. Note: If the command AT is omitted, the design proceeds for all cross sections of the wall or panels, as applicable, defined by the SURFACE DIVISION X or SURFACE DIVISION Y input values.
STAAD Commands and Input Instructions 5-428 Section 5 5.54 End Run Specification Purpose This command must be used to terminate the STAAD run. General format: FINISH Description This command should be provided as the last input command. This terminates a STAAD run.
Section 5 5-429
STAAD Commands and Input Instructions 5-430 Section 5
Index Index by Section Numbers A ANALYSIS FACILITIES, 1.18 ANGLE, AASHTO, from User Table, 5.19 ASSIGN of, 1.7.5, 5.20.5 BETA, 1.5.3 specification of, 1.7.2 user table, 1.7.3, 5.19 allowable code stress, 2.13.2 axial stress, 2.13.2 bending-axial stress interaction, 2.13.2 bending stress, 2.13.2 general comments, 2.13.1 minimum metal thickness, 2.13.4 MOVING LOAD, 1.17.1, 5.31.1, 5.32.12 shear stress, 2.13.2 stability requirements, 2.13.
2 Index C CONCRETE DESIGN- 3.0 parameter 5.51.2, Table 3.1 CABLE command of, 1.11, 5.23.2, description, 1.11 nonlinear, 1.18.2.5 CALCULATE RAYLEIGH (FREQUENCY), 5.33 specifications, 5.51 terminator, 5.51.5 CONCRETE TAKE OFF, 5.51.4 CONSTANTS, 5.26 COORDINATE CANADIAN SEISMIC, 5.31.2.10 systems, 1.5 Cartesian Coordinate System, 1.5.1 joint, 5.11 CASTELLATED BEAMS, 2.16 CQC, Modal Combination, 5.32.10.1 CB parameter, Table 2.1 & 2.2 CURVED MEMBERS, 1.7.8, 5.20.
Index DESIGN OF I-SHAPED BEAMS F PER ACI-318, 3.8.4 FINISH, 5.53 DFF parameter, Table 2.1 FINITE ELEMENT DJ1, DJ2 parameters, Table 2.1 Information, 1.6 DIAPHRAGM (see MASTER/SLAVE) Plate/shell, 1.6.1, 5.13, 5.21 DIRECTION, 5.27.3 Solid, 1.6.2, 5.13 DISPLACEMENTS PRINT command, 5.41, 5.42 DMAX parameter, Table 2.1& 2.2 FIREPROOFING ON MEMBERS, 5.20.9 FIXED END MEMBER LOAD, 1.16.4, 5.32.7 DMIN parameter, Table 2.1& 2.2 FLOOR LOAD, 5.32.4 DOUBLE ANGLE, 2.2.1, 5.19 FLOOR WEIGHT, 5.31.2.1, 5.31.2.
4 Index GROUP SPECIFICATION, 5.48 H Harmonic Time History Load, 5.31.6 I IBC 2000/2003 LOAD, 5.31.2.6 IGNORE LIST, 5.9 IMPERFECTION Load, 1.18.2.2 LOAD SYSTEMS Definition of, 5.31 LOADING, 1.16, 5.32 LOCAL COORDINATE, 1.5.2, 1.5.3 LX parameter, Table 2.1 & 2.2 LY parameter, Table 2.1 & 2.2 LZ parameter, Table 2.1 & 2.2 M IMPERFECTION, member, 5.26.6 MAIN parameter, Table 2.1& 2.2 INACTIVE MEMBERS, 1.20, 5.18 MASS MODELING, 1.18.3 INCLINED SUPPORT, 5.27.2 MASTER/SLAVE, 1.15, 5.
Index MEMBER PROPERTIES, 1.7, 5.20 MEMBER RELEASE, 1.8, 5.22 MEMBER SELECTION SPECIFICATION, 5.47.3 MEMBER STRESSES (SPECIFIED SECTIONS), 1.19.4, 5.41 TIMBER DESIGN, 5.50, 5.50.1 PARTIAL MOMENT RELEASE, 5.22.1 P-DELTA ANALYSIS, 1.18.2.1 PERFORM ANALYSIS, 5.37 PERFORM CABLE, 5.37 MEMBER Tension-Only 1.9, 5.23.3 PERFORM IMPERFECTION, 5.37 MEMBER TRUSS, 1.9, 5.23 PERFORM ROTATION, 5.17 MEMBER WEIGHT, 5.31.2 PERFORM STEADY STATE, 5.37 MESH GENERATION, 5.14 PERIOD, 5.33, 5.34 MODAL CALCULATION, 5.
6 Index PRISMATIC, 5.19 SELECT ALL, 5.47.3, 5.50.3 PRISMATIC PROPERTY, 1.7.1, 5.20.2 SELECT MEMBER, 5.47.3, 5.50.3 PROFILE, 5.47.1 SELECT OPTIMIZED, 5.47.4 PROPERTY SPEC, 5.20.2 SELECT WELD TRUSS, 5.47.3 R SELFWEIGHT, 5.32.9 SEPARATOR, 5.6 RATIO parameter, Table 2.1& 2.2 RAYLEIGH FREQUENCY, 5.33 REACTIONS (SUPPORT) PRINT command, 5.41 REFERENCE LOAD, 5.31.1 REFERENCE POINT, 1.5.3 RELEASE members, 1.8, 5.22.1 elements, 5.22.2 REPEAT, 511, 5.12, 5.13 REPEAT ALL, 5.11, 5.12, 5.
Index STEEL TABLE, 5.20.1 TORSION parameter, Table 2.1 STEEL TAKE-OFF, 5.49 TRACK parameter, Table 2.1& 2.2 STIFF parameter, Table 2.1 TRAPEZOIDAL LOAD, 5.32.3 STRUCTURE GEOMETRY, 1.5 TRUSS MEMBERS, 1.9, 5.23.1 STRUCTURES – Type, 1.3, 5.2 TUBE, 1.7.2, 5.19 U SUBGRADE, 5.27.3 SUBSTITUTION - JOINT, 5.15 UBC SUBSTITUTION - MEMBER, 5.15 Accidental Torsion, 5.31.2 SUBSTITUTION - COLUMN, 5.15 UBC LOAD, 5.31.2 SUPPORT DISPLACEMENT, 1.16.7, UBC SEISMIC LOAD, 1.17.2, 5.32.8 5.31.2.1, 5.32.
8 Index
