Civil Engineering Reference
In-Depth Information
Live Loads
To determine the worst cases of loading on an intermediate cross girder due
to live loads, we can study different longitudinal sections through vehicles,
distributed loads, and sidewalks of Load Model 1 acting on the bridge, as
shown in
Figure 4.46
.
From the different sections, we can find that the max-
imum concentrated and distributed loads transferred to the intermediate
cross girder are shown in
Figure 4.46
. The case of loading for the evaluation
of maximum positive bending moment due to live loads on an intermediate
cross girder can be studied, as shown in
Figure 4.46
.
The case of loading is
that the larger concentrated load from vehicles transferred is located at the
centerline (midspan) of an intermediate cross girder, with maximum bend-
ing moment located at the midspan as shown in
Figure 4.46
. The maximum
positive bending moment is calculated as follows:
M
L
:
L
:
maximum positive bending moment
ð
Þ
¼
623
:
25
6
270
2
54
2
:
5
1
:
25
15
2
:
5
3
:
75
30
1
5
:
5
¼
2725
:
1kNm
The case of loading for the evaluation of maximum negative bending
moment due to live loads on an intermediate cross girder can be also studied,
as shown in
Figure 4.47
.
The maximum negative bending moment is
calculated as follows:
2.5 kN/m
9 kN/m
6 m
6 m
270
270
180
180
90
90
54 kN/m
30
k
N/m
30 kN/m
15 kN/m
15 kN/m
100
150
a
A
0.5
B
1.2
1.2
100
150
2 m
2
2
2.5
2
1.0
1.0
1
1.0
0.5
0.5
6 m
6 m
783.75 kN
623.25 kN
4.8
4.8
Figure 4.46 Case of loading for maximum positive bending moment from live loads
acting on an intermediate cross girder.
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