Civil Engineering Reference
In-Depth Information
Allowable girder tensile bending capacity,
M
tall
=
0.55
(F
y
)(S
n
)
Allowable girder shear capacity,
V
all
=
0.35
(F
y
)(A
w
)
=
0.35
(
50
)(
53.13
)
=
929.8 kips
Compression flange splices
Try a single plate flange splice as shown in
Figure E9.9.
For the splice cross section to be at least equal to the flange cross section,
t
s
=
2.5 in.
Since the plates are spliced on the exterior of the flanges, the moment of
inertia at the splice will be greater than the moment of inertia of the cross
section being spliced. There must be enough bolts each side of the splice to
develop the flange strength.
The maximum force in the compression flange plate at the splice location
(average at the centroid) is
8800
(
12
)
4965
(
1
+
42.5
/
45
)
2
F
f
=
(
2.5
)(
20
)
=
21.3
(
0.97
)(
50
)
=
1031.5 kips.
Note that a conservative approximation for the actual flange force,
F
f
, can
be determined from the couple resisting the applied bending moment as
8800
(
12
)
87.5
F
f
=
=
1206.9 kips
20"
t
s
2-1/2"
5/8"
FIGURE E9.9
