Civil Engineering Reference
In-Depth Information
35 kips
6"
¾"
H
y
7/16"
30½"
x
H
¾"
12"
FIGURE E8.2
, that reduce the normal lateral bending stress have
been developed as a corrective measure since the flexure analogy overesti-
mates normal flange stresses due to warping. For the case of
L/a
Modification factors,
β
=
1.20 and
torsional moment,
T
, applied at the center of the span,
β ∼
0.94 (Salmon and
Johnson, 1980; Kulak and Grondin, 2002).
362.9
β
σ
bH
=
=
20.2
β =
20.2
(
0.94
)
=
19.0 ksi,
0.75
(
12
)
2
/
6
[
]
which is close to the value of 18.0 ksi obtained in Example 8.1. The flexure
analogy models flange normal warping stresses well for many typical steel
railway bridge elements.
6.72
2
=
V
H
=
3.36 kips,
3
(
3.36
)
τ
bH
=
=
0.56 ksi,
2
[
12
(
0.75
)
]
