Design Examples of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 371

due to dead loads on an intermediate cross girder (see Figure 4.133 ) as
follows:

Q D : L : ¼ 3 9 = 2+2 21 : 6 ¼ 56 : 7kN

M D : L : ¼ 3 9 2 = :

6 1

: :

6 3

:

6 ¼ 147 kNm

8+21 8+21

Live Loads
To determine the maximum reactions due to live loads transferred by the
stringers to the cross girders, the case of loading shown in Figure 4.134 is
studied. The maximum reaction R L.L. can be calculated as follows:

R L : L : ¼ 125 + 2 125 4 ð : 5 1 : 6 Þ= 5 + 125 4 ð : 5 3 : 2 Þ= 5+40 0 : 5

9kN
The maximum straining actions due to live loads on an intermediate
cross girder can be then calculated (see Figure 4.135 ) as follows:

0 : 25 = 4 : 5+40 2 : 1 1 : 05 = 4 : 5 ¼ 342 :

Q L : L : ¼ 2 342 : 9 ¼ 685 : 8kN

M L : L : ¼ 342 :

8 1

: :

9 3

:

6 ¼ 1851

:

8 + 342 66 kNm

Dynamic Factor F

L F ¼ 2 9 ¼ 18m

2 : 16

F 3 ¼ p

18 2 +0

: 73 ¼ 1 : 264, F 3 1 : 0 and 2 : 0 :

0 :

125 kN 125 kN 125 kN 125 kN

q vk = 40 kN/m q vk = 40 kN/m

2.1 0.8 1.6 1.6 1.6 0.8 0.5

4.5 m 4.5 m

R L.L = 342.9 kN
Figure 4.134 The case of loading producing maximum straining actions from live loads
on an intermediate cross girder.