HAC_Technical-Guide

188 189
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
Case II: Shear force parallel, Ψparallel=2.0
Concrete edge breakout may be limited by the side concrete
edge breakout, even if the load acts in a different direction. The
side concrete edge breakout is equal to twice the perpendicular
concrete edge breakout strength.
• C
a1
is measured from the corner to the center of the anchor
channel.
• The analysis shall consider a maximum of three anchors.
• Projected areas are in accordance with ACI 318-14.
Calculation of projected area for a single anchor in a deep
member, A
vco
:
A
vco
= (1.5c
a1
) x {[2(1.5c
a1
) x [(1.5c
a1
) + [(N
a
-1) x s)] +(1.5c
a2
)}
Calculation of projected area of the failure surface, Avc:
A
vc
= {min (h, 1.5 c
a1
) x [min (c
a2
,
1
, 1.5c
a1
) + (N
a
-1) + (c
a2
,
2
, 1.5c
a1
)]}
where
N
a
= number of anchors
Figure 7.4.4.4 — Projected area due to an anchor channel loaded in shear acting
parallel to the long channel axis. Verification of side concrete edge breakout.
Ψ
ed,v
: Modification factor for edge effect in Shear
The modification factor for edge effect for a single anchor or
group of anchors loaded in shear, ψ
ed,V
, shall be calculated as
follows using the smaller value of c
a2
.
If c
a2
≥1.5c
a1
, then ψ
ed,V
= 1.0
If c
a2
< 1.5c
a1
, then
0.1)
5.1
(3.07.0
1
2
,e
£+=Y
a
a
Vd
c
c
c
a1
: Distance from the edge to axis (in.) (edge to center line of
channel)
c
a2
: Edge distance (in) of anchor channel in direction 2
If anchors are located close to an edge so that there is not
enough space for a complete breakout prism to develop, the
strength of the anchor is further reduced beyond that reflected
in A
Vc
/A
Vco
. If the smallest side cover distance is greater than
or equal to 1.5hef, a complete prism can form and there is no
reduction (ψ
ed,V
= 1). If the side cover is less than 1.5h
ef
, the
factor ψ
ed,N
is required to adjust for the edge effect
Ψ
C,v
: Modification factor for cracked/uncracked concrete
For anchors located in a region of a concrete member where
analysis indicates no cracking at service loads, the following
modification factor shall be permitted ψ
c,V
= 1.4
ψ
c,V
= 1.4 For anchors located in a region of a concrete member
where analysis indicates cracking at service load levels, the
following modification factors shall be permitted:
ψ
c,V
= 1.0 For anchors in cracked concrete without
supplementary reinforcement or with edge
reinforcement smaller than a No. 4 bar
ψ
c,V
= 1.2 For anchors in cracked concrete with straight
reinforcement of a No. 4 bar or greater between the
anchor and the edge
ψ
c,V
= 1.4 For anchors in cracked concrete with reinforcement
of a No. 4 bar or greater between the anchor and the
edge, and with the reinforcement enclosed within
stirrups spaced at not more than 4 in.
Ψ
h,v
: Modification factor for concrete thickness
The modification factor for anchors located in a
concrete member where ha < 1.5c
a1
, ψ
h,V
shall be calculated as
0.1
.5.1
1
,
³=Y
a
a
Vh
h
c
c
a1
…Distance from the edge to axis (in.)
h
a
….Height of the concrete member (in)
ψ
h,V
shall not be taken less than 1.0.
For anchors located in a concrete member where
h
a
< 1.5c
a1
, tests have shown that the concrete breakout strength
in shear is not directly proportional to the member thickness h
a
.
The factor ψ
h,V
accounts for this effect.
For anchors located in a concrete member where h
a
< 1.5c
a1
,
tests (CEB 1997; Eligehausen et al. 2006b) have shown that the
concrete breakout strength in shear is not directly proportional
to the member thickness h
a
. The factor ψ
h,V
accounts for this
effect
Anchor reinforcement in longitudinal
shear(ACI 318-11 D6.2.9)
For conditions where anchor reinforcement is provided as
illustrated in figure 7.4.4.5, the concrete breakout strength in
longitudinal shear can be that of the reinforcement strength.
The anchor reinforcement of an anchor channel shall be
designed for the total longitudinal shear load acting at the
anchor channel anchors and channel bolts. Such anchor
reinforcement shall be arranged at all anchors of an anchor
channel.
Anchor reinforcement shall consist of stirrups made from
deformed reinforcing bars with a maximum diameter of 5/8 in
(No. 5 bar). The enclosing anchor reinforcement should be in
contact with the anchor and as close to the concrete surface as
possible, while still observing minimum cover requirements.
To ensure yielding of the anchor reinforcement, the enclosing
anchor reinforcement in Fig. R17.5.2.9a should be in contact
with the anchor and placed as close as practicable to the
concrete surface
S ection view
B ottom view
Figure 7.4.4.5 — Anchor reinforcement to preclude concrete breakout in shear
acting along the longitudinal axis of the anchor channel
In accordance with the provisions of ACI 318-14, 17.5.2.10.8.2,
longitudinal shear anchor reinforcement shall consist of stirrups
made from deformed reinforcing bars with a maximum diameter
of 5/8 in (No. 5 bar) and straight edge reinforcement with a
diameter not smaller than the diameter of the stirrups. Only one
bar at both sides of each anchor shall be assumed as effective.
The distance of this bar from the anchor shall not exceed 0.5c
a1
and the anchorage length in the breakout body shall not be less
than 4 times the bar diameter. The distance between stirrups
shall not exceed the smaller of anchor spacing or 6 inches.
Figure 7.4.4.6 — Anchor reinforcement to resist shear loads acting
along the longitudinal axis of the anchor channel.
Because the anchor reinforcement is placed below where the
shear is applied, the force in the anchor reinforcement will be
larger than the shear force acting on the anchor channel bolts. If
a shear load (V
ua,y
) is acting on the anchor channel, the resultant
factored tension force of the anchor reinforcement, N
ua,re
, shall
be computed by the following equation:
)(1
z
e
N
s
,reua,
NlbfV yua
÷
ø
ö
ç
è
æ
+=
e
s
= distance between reinforcement and shear force
acting on the anchor channel (in)
z = internal lever arm of the concrete member, (in)
= 0.85 (h – h
ch
– 0.5d
a
)
< (2h
ef
, 2c
a1
)