HAC_Technical-Guide

398 399
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
4.1.3.2.4
ACI 318-14 Chapter 17
Pull-out strength Tension
PROFIS Anchor Channel has determined that anchor element #3 controls for pullout
in tension.
Per ESR-3520 Section 4.1.3.2.4, nominal pullout strength (Npn) is calculated using
ACI 318 anchoring-to-concrete provisions. This example is based on ACI 318-14
provisions; therefore, pullout calculations will be per ACI 318-14 Chapter 17.
ФN
pn
≥ N
a
ua
N
pn
= Ψ
c,P
. λ . N
p
ACI 318-14 Eq.(17.4.3.1)
N
p
= 8 A
brg
f΄
c
ACI 318-14 Eq. (17.4.3.4)
A
brg
for an HAC-50F anchor channel = 0.40 in2 ESR-3520 Table 8-1
λ =1 normal weight concrete Reference 1st of example
f΄
c
= 6000 psi Reference 1st of example
Concrete Ψ
c,P
ACI 318-14 17.4.3.6
Cracked 1
Uncracked 1.25
Considering cracked concrete Ψ
c,P
=1.0
Ф factor:
Condition A (Ф =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 (Ф =0.70) is considered when
• No Supplementary reinforcement is present
Assume Condition B
Ф =0.70
N
a
ua3
= 786 lbs
N
p
= (8) (0.40 in2) (6000 lb/in2) = 19,195 lb
N
pn
= (1.0) (1.0) (19,195 lb) = 19195 lb
Ф N
pn
= 13437 lbs
N
aua3
β
N,pn
: _______ x100 = 6 %
Ф N
pn
Code Discussion Calculations
Step 7: Concrete strength
ESR-3520 section
4.1.3.2.3
ACI 318-14 Chapter 17
Concrete breakout strength in Tension.
PROFIS Anchor Channel has determined that anchor element #3 controls for concrete
breakout in tension.
Per ESR-3520 Section 4.1.3.2.3, nominal concrete breakout strength (N
cb,3
) is
calculated using ESR 3520 Equation (6). The value calculated for concrete breakout
strength in tension (N
cb
) is based on the location of the anchor element being
considered. The basic concrete breakout strength in tension (N
b
) is not dependent
on the anchor element being considered or the concrete geometry. Therefore, the
calculated value for N
b
will be the same for each anchor element.
Ф N
cb
≥ N
a
ua
N
cb
= N
b
· ψ
s,N
· ψ
ed,N
· ψ
co,N
· ψ
cp,N
· ψ
c,N
ESR-3520 Equation(6)
N
b
= basic concrete breakout strength in tension
ψ
s,N
= modification factor for anchor spacing
ψ
ed,N
= modification factor for edge effects
ψ
co,N
= modification factor for corner effects
ψ
c,N
= modification factor cracked/uncracked concrete
ψ
cp,N
= modification factor for splitting
Nominal concrete breakout strength in tension for Anchor Element #3
1.5
ef
'
cNch,b,3
hfα24N ××××= l
Calculate the basic concrete breakout strength
in tension (N
b,3
). ESR-3520 Equation (7)
λ = 1 normal weight concrete Reference 1st of example
f΄
c
= 6000 psi Reference 1st of example
HAC-50F channel: h
ef
= 4.173 in ESR-3520 Table 8-1
0.1
1.7
α
15.0
Nch,
£
÷
÷
ø
ö
ç
ç
è
æ
=
ef
h
ESR-3520 Equation (8)
The parameter α
ch,N
is a factor that is used to account for the influence of the channel
size on the concrete breakout capacity in tension. The value 7.1 is a constant. ESR-
3520 Table 8-1 provides minimum effective embedment depth values (h
ef,min
) for each
anchor channel size. The h
ef,min
value given for an HAC-50F channel will be used for h
ef
in this example.
Calculate the modification factor for anchor influence (ψ
s,N,3
).
å
+
=
ú
ú
û
ù
ê
ê
ë
é
×
÷
÷
ø
ö
ç
ç
è
æ
-+
=
1n
2i
3
a
ua,
i
a
ua,
1.5
Ncr,
i
N,3s,
N
N
s
s
11
1
y
ESR-3520 Equation (10)
The value calculated for concrete breakout strength in tension (N
cb
) is based on the
location of the anchor element being considered. Therefore, for this example, ψ
s,N
is
calculated to account for the influence of anchor element #1 and anchor element #3
on anchor element #2.
Concrete breakout: ФN
cb
N
aua3
= 786 lbs
⎛ 4.173
⎞
0.15
α
ch,N
= ⎜
______
⎜ = 0.923. < 1
⎝ 7.1 ⎠
N
b,3
= 24 · 1 · 0.923 · 60000 · (4.173)
1.5
= 14634 lbs