HAC_Technical-Guide

404 405
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
Code Discussion Calculations
Step 7: Concrete strength
ESR-3520 Section
4.1.3.3.4.
ACI 318-14 Chapter 17
Concrete pryout strength - perpendicular shear (Anchor a3)
The ICC-ES Acceptance Criteria AC232 includes amendments to the ACI 318
anchoring to concrete provisions. These amendments are given in Section 3.1
Strength Design – Amendments to ACI 318. Part D.6.3.2 (ACI 318-11) and Section
17.5.3.2 (ACI 318-14) of these amendments requires the factor ψ
s,N
to be modified
when calculating concrete pryout strength in shear. All of the parameters used to
calculate ψ
s,N
in tension are used except the parameter (N
aua,i
/ N
aua,3
). The shear loads
acting on the anchor elements are substituted for the tension loads such that (V
aua,i
/
V
aua,3
) is used instead of (N
aua,i
/ N
aua,3
).
These provisions for calculating concrete pryout strength are also given in ESR-3520
Section 4.1.3.3.4.
V
cp,y,3
= k
cp
N
cb,3
ESR-3520 Equation (41)
K
cp3
= 2.0 ESR-3520 Table 8-6
N
cb3
= N
b3
· ψ
s,N3
· ψ
ed,N3
· ψ
co,N3
· ψ
c,N3
· ψ
cp,N3
ESR-3520 Equation (6)
s
i
= spacing between each anchor element = 5.91 in
s
xx,1
= distance of each influencing anchor element from anchor element #3
s
1,
3 = distance from anchor element #1 to anchor element #3 = 11.812 in
s
2,3
= distance from anchor element #2 to anchor element #3 = 5.906 in
s
cr,N
= critical anchor spacing for tension loading (h
ef
=4.173 in)
efef
ef
Ncr
hh
h
s 3
1.7
3.1
8.22
,
³
÷
÷
ø
ö
ç
ç
è
æ
-=
ESR-3520 Equation (10)
The parameter ψ
s,N
is a modification factor that is used to account for the influence of
adjacent anchor elements on the anchor element being considered.
V
a
ua,1
= tension load on anchor element #1=421 lb
V
a
ua,2
= tension load on anchor element #2 1461 lb
V
a
ua,3
= tension load on anchor element #3=1618 lb
The calculated value for V
cp,y,3
will be multiplied by a strength reduction factor
(φ-factor) to give a design strength (φV
cp,y,3
).
The calculated φV
cp,y,3
value for anchor element #3 will be checked against the factored
load acting on anchor element #3 (V
ua3
) to obtain the % utilization (V
ua3
/ φV
cp,y,3
).
The anchor element with the highest % utilization will control the design with respect
to concrete pryout failure in shear.
Pryout: ФN
cp,yb
s
cr,N
= 16.98 in
refer to concrete breakout tension influence of
anchor element #1 on anchor element #3:
1.5
11.812 421
1
16.980 1618
0.0437
in lbs
in lbs
æö
-
ç÷
èø
=
influence of anchor element #2 on anchor
element #3:
1.5
5.906 1461
1
16.980 1618
0.4756
in lbs
in lbs
æö
-
ç÷
èø
=
, ,3
1
0.658
1 (0.0437 0.4756)
sN y ==
++
( )
,,
,
0.5 0.50 16.98
8.49
cr N cr N
cr N
c s in
c in
==
=
767.0
1.0
8.49in
5.0in
Ned,
0.5
Ned,
=\
<
÷
ø
ö
ç
è
æ
=
y
y
in 6.984 c
in 0.984 in 6.00 c
x)a2(
x)a2(
=
+=
+
+
907.0
1.0
8.49in
6.984in
49.8
1
c
c
N,3co,
0.5
N,3co,
,
0.5
Ncr,
x)a2(
)(2
=\
<
÷
ø
ö
ç
è
æ
=
=
=
÷
÷
ø
ö
ç
ç
è
æ
®¥=
-
-
y
y
inc
c
Ncr
xa
s,N
ed,N
co,N
cp,N
c,N
3
,3
, ,3 ,3
, ,3
cp,y,3
a
ua,3
, ,3
ψ 0.658
ψ 0.767
ψ 0.907
ψ 1.0
ψ 1.0
14634
6699
2
2 6699 13397
0.7
V 9378lbs
V 1618
1618
100% 1
9378
b
cb
cp
cp y cb
cp
cp y
cp v
N lbs
N lbs
k
V k xN
V x lbs lbs
Condition B
lbs
x
j
j
b
=
=
=
=
=
=
=
=
=
==
=
=
=
æö
==
ç÷
èø
8%
Code Discussion Calculations
Step 7: Concrete strength
ESR-3520 section
4.1.3.3.3
ACI 318-14 Chapter 17
Concrete breakout strength in perpendicular shear for anchor element #3
ФV
cb
≥ V
a
ua
V
cb,3
= V
b,3
· ψ
s,V,3
· ψ
co1,V,3
· ψ
co2,V,3
· ψ
h,V, 3
· ψ
c,V,3
ESR-3520 Equation (30)
V
b
= Basic concrete breakout strength in shear
ψ
s,V
= Modification factor for anchor spacing
ψ
co,V
= Modification factor for corner effects
ψ
c,V
= Modification factor cracked/uncracked concrete
ψ
h,V
= Modification factor for concrete thickness
Calculate the basic concrete breakout strength in shear (V
b,3
).
( )
3
4
a1
'
cVch,b
cfαV ×××= l
ESR-3520 Equation (31)
λ… Modification for lightweight concrete
Lightweight concrete = 0.75
Sand-Lightweight concrete = 0.85
α
ch,V
… Influence factor for channel size (10.50, max.)
f´
c
… Concrete compressive strength (psi) (8,500 psi, max)
c
a1
… Perpendicular edge distance (in.) (edge to center line of channel)
Concrete edge breakout: ФV
cb,y
( ) ( )
3
4
5.0in6,000psi(10.50)0.1V
b
×=
lbs954,6V
b
=\
Figure 14.1.21 — Design example – reduction factors of V
cb