Design Examples of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 276

Live Loads
To determine the live loads acting on main trusses in the longitudinal direc-
tions, we can study different lateral sections through vehicles, distributed
loads, and sidewalks of Load Model 1 acting on the bridge, as shown in
Figure 4.51 . From the lateral section shown in Figure 4.51 , we can find that
the maximum concentrated and distributed loads transferred to a main truss
are 375 kN and 43.8 kN/m, respectively, as shown in Figure 4.52 . We can
also calculate the negative distributed reactions acting on a main truss in the
longitudinal direction by investigating the case of loading shown in
Figure 4.53 . The negative distributed load acting on a main truss is
0.83 kN/m as shown in Figure 4.54 . The calculated dead and live loads

150 kN 150 100

100

50 50

9 kN/m 2

5 kN/m 2 2.5 kN/m 2 5 kN/ m 2

A B

2 m 2 2

2 1 1 2

1

0.5 0.5 0.5 0.5

12 m

Reaction from concentrated loads = 375 kN

Reaction from distributed loads = 43.8 kN/m
Figure 4.51 Maximum reactions due to live loads transferred by cross girders on main
trusses.

375 kN 375 kN

q vk = 43.8 kN/m

1.2 m
Figure 4.52 Live loads acting on main trusses.

5 kN/m 2

2 m 12 m

2 m

Negative reaction from distributed loads = -0.83 kN/m
Figure 4.53 Negative reactions due to live loads transferred by cross girders on main
trusses.