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Cast-In Anchor Channel Product Guide, Edition 1 • 02/2019

1. Anchor

Channel Systems

2. HAC

Portfolio

3. HAC

Applications

4. Design

Introduction

5. Base material 6. Loading

7. Anchor Channel

Design Code

8. Reinforcing

Bar Anchorage

9. Special Anchor

Channel Design

10. Design

Software

11. Best

Practices

12. Instructions

for Use

13. Field Fixes

14. Design

Example

7.1 & 7.2 Introduction to

Anchor Channel Design

7.3 Anchor Channel Tension Design 7.4 Anchor Channel Shear Design (y) 7.4 Anchor Channel Shear Design (X)

7.5 Interaction Equations

(Combined Loading)

7.6 Seismic Design

Steel Concrete Steel Concrete Steel Concrete

Cracks

Cracked Uncracked

Figure 7.3.2.14 — Cracked and uncracked concrete.

cp,N

= modification factor for splitting

The modification factor for anchor channels designed for

uncracked concrete without supplementary reinforcement to

control splitting, ψ

cp,N

, shall be computed in accordance with Eq.

(17) or (18). The critical edge distance, c

, shall be taken from

Table 8-4 of ESR-3520.

= critical edge distance for splitting

cr,N

= critical anchor edge distance

s,min

= minimum edge distance

cp,N

Uncracked concrete with no

supplementary reinforcement

If c

a,min

≥ c

ESR 3520 eq (17) 1

If c

a,min

< c

ESR 3520 eq (18)

Uncracked concrete with no suppplementary reinforcement

If Camin>Cac ESR 3520 eqn (17)

If Camin<Cac ESR 3520 eqn (18)

Uncracked Concrete With Supplementary Reinforcement 1

Cracked Concrete 1

Ncp ,

Ncr

Ncp

MAX

,min,

;

Uncracked concrete with

supplementary reinforcement

Cracked concrete 1

The basic concrete breakout strength can be achieved if

the minimum edge distance ca,min equals c

cr,n

. Test results,

however, indicate that it require minimum edge distances

exceeding c

cr,n

to achieve the basic concrete breakout strength

when tested in uncracked concrete without supplementary

reinforcement to control splitting. When a tension load is

applied, the resulting tensile stresses at the embedded end

of the anchor are added to the tensile stresses induced due

to anchor installation, and splitting failure may occur before

reaching the concrete breakout strength. To account for this

potential splitting mode of failure, the basic concrete breakout

strength is reduced by a factor ψ

cp,N

if c

a,min

is less than the

critical edge distance c

. If supplementary reinforcement to

control splitting is present or if the anchors are located in a

region where analysis indicates cracking of the concrete at

service loads, then the reduction factor ψ

cp,N

is taken as 1.0. The

presence of supplementary reinforcement to control splitting

does not affect the selection of Condition A or B.

ϕ factor for concrete breakout strength in tension

Condition A (ϕ=0.75) is considered when

• Supplementary reinforcement is present

• Reinforcement does not need to be explicitly designed for the

anchor channel

• Arrangement should generally conform to anchor

reinforcement

• Development is not required

Condition B (ϕ =0.70) is considered when

• No Supplementary reinforcement is present

Condition ϕ

A 0.75

B 0.70

Figure 7.3.2.15 — Arrangement of anchor reinforcement for anchor channels

loaded by tension load in a narrow member.

Figure 7.3.2.16 — Arrangement of anchor reinforcement for anchor channels

loaded by tension load at an edge.

Anchor reinforcement in tension

As opposed to supplementary reinforcement, anchor

reinforcement acts to transfer the full design load from the

anchors into the reinforcement. Hence, concrete breakout

is precluded. Where anchor reinforcement is developed in

accordance with ACI 318 on both sides of the breakout surface

for an anchor of an anchor channel, the design strength of the

anchor reinforcement shall be permitted to be used instead

of the concrete breakout strength in determining ΦNn or ΦVn,

dependent upon the if the load is tension or shear. A strength

reduction factor of 0.75 shall be used in the design of the anchor

reinforcement. Anchor reinforcement can be utilized in tension,

longitudinal shear, and perpendicular shear. An explicit design

and full development are required for anchor reinforcement.

Tension* (AC232 D5.2.10.9)

In accordance with the provisions of AC232 D5.2.10.9, the

tension anchor reinforcement shall consist of stirrups made

from deformed reinforcing bars with a maximum diameter of 5/8

in (No. 5 bar)

Figure 7.3.2.17 — Arrangement of anchor reinforcement for anchor channels

loaded in tension, plan view.

= effective embedment depth

= factored tension load

ℓ

= development length

ℓ

= development length in tension of a deformed bar or

deformed wire with a standard hook, measured from

critical section to outside end of hook

Where anchor reinforcement is developed in accordance with

ACI 318-11 Chapter 12 or ACI 318-14 Chapter 25 on both sides

of the breakout surface for an anchor of an anchor channel,

the design strength of the anchor reinforcement, ϕN

, shall be

permitted to be used instead of the concrete breakout strength,

ϕN

, in determining ϕN

. The anchor reinforcement for one

anchor shall be designed for the tension force, N

, on this

anchor using a strut-and-tie model. The provisions in Figure -

7.3.2.17 shall be taken into account when sizing and detailing

the anchor reinforcement. Anchor reinforcement shall consist of

stirrups made from deformed reinforcing bars with a maximum

diameter of 5/8 in. (No. 5 bar) (16 mm). A strength reduction

factor, ϕ, of 0.75 shall be used in the design of the anchor

reinforcement.

Figure 7.3.2.17 — Arrangement of anchor reinforcement for anchor channels

loaded in tension, section view.