Civil Engineering Reference
In-Depth Information
Figure 2.13
EXAMPLE 2.7
Calculate the nominal or theoretical ultimate moment strength of the beam section shown in Figure
2.13 if
f
y
60,000 psi and
c
f
3000 psi. The 6-in.-wide ledges on top are needed for the support
of precast concrete slabs.
SOLUTION
T
A
s
f
y
(4.00)(60)
240 k
c
)(area of concrete
A
c
stressed to 0.85
f
c
)
C
(0.85
f
c
A
c
0.85
f
Equating
T
and
C
and solving for
A
c
T
0.85
f
240
(0.85)(3)
94.12 in.
2
A
c
c
Finger piers for U.S. Coast Guard base, Boston. (Courtesy of EFCO Corp.)
