Design Examples of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 367

located at the closest load (point a in Figure 4.130 ) , while the second case of
loading is that the centerline of the stringer is located under one of the inter-
mediate concentrated loads, with maximum bending moment located at
midspan, and finally, the third case of loading is that the stringer span is cov-
ered by the distributed live loads, with maximum bending moment located
at midspan. The three cases of loading are shown in Figure 4.130 :
M L : L : ð Þ ¼ 220 :

83 1

:

85 125 1

:

6 ¼ 208

:

case of loading 1 54 kNm

M L : L : ð case of loading 2 Þ ¼ 187 : 5 2 : 25 125 1 : 6 ¼ 221 : 875 kNm

5 2 M L : L : ð case of loading 3 Þ ¼ 40 4 : = 8 ¼ 101 : 25 kNm

Dynamic Factor F

Assuming a track with standard maintenance, therefore,
L F ¼ 4

: 5+3 ¼ 7 : 5m

125 kN 125 kN 125 kN

B

A

Case of loading 1

a

0.25 1.6 0.4 1.2 1.05

4.5 m

Y A = 220.83 kN Y B = 154.17 kN

125 kN 125 kN 125 kN

B

A

Case of loading 2

1.6 1.6 0.65

0.65

4.5 m

Y B = 187.5 kN

Y A = 187.5 kN

q vk = 40 kN/m

A

B Case of loading 3

4.5 m

Y B = 90.0 kN
Figure 4.130 Cases of loading for the maximum bending moment acting on a stringer.

Y A = 90.0 kN