Civil Engineering Reference
In-Depth Information
7.20 (a)
Determine the tensile development length required for the uncoated #8 bars shown if normal-weight concrete
is used and the bars are straight.
4000 psi,
f
y
60,000 psi.
(b)
Repeat part (a) if 180
hooks are used.
Assume side, top, and bottom cover in all cases to be at least
c
f
2
2
in. Use ACI Equation 12-1 and compute value of
K
tr
.
21"
3 @ 5"
= 15"
3"
3"
3"
4 #8
#3 stirrups
@ 6" O.C.
27"
30"
7.21
Are the uncoated #8 bars shown anchored suffi-
ciently with their 90
hooks?
3000 psi,
f
y
60 ksi.
The stress in the bars is 50 ksi. Side and top cover is on
bar extensions. Normal-weight concrete is used. Use ACI
Equation 12-1 and assume
K
tr
0. (
Ans.
dh
13 in.)
7.22
Repeat Problem 7.6 if the bars are in compression.
c
f
2
2
2" clear
#8
12" clear
14"
7.23
Repeat Problem 7.7 if the bars are in compression.
(
Ans.
18 in.)
15"
