Civil Engineering Reference
In-Depth Information
In Problems 4.10 to 4.22 design rectangular sections for the beams, loads, and
values shown in the accompanying il-
lustrations. Beam weights are not included in the loads shown. Show sketches of cross sections, including bar sizes,
arrangement, and spacing. Assume concrete weighs 150 lb/ft
3
,
f
y
60,000 psi, and
c
f
4000 psi.
Problem 4.10
L
= 30 k
D
= 3 k/ft
12'
12'
24'
0.18
f '
c
f
y
Use
ρ =
4.11
Repeat Problem 4.10 if
D
2 k/ft and if
L
20 k. (
One ans.
14 in.
28 in. with 3 #11 bars.)
Problem 4.12
L
= 20 k
L
= 20 k
D =
1.5 k/ft
10'
10'
10'
30'
0.18
f '
c
f
y
Use
ρ
=
4.13
Repeat Problem 4.12 if
D
2 k/ft. (
One ans.
16 in.
33 in. with 4 #11 bars.)
