Design Examples of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 425

s

a

Fsin a

4 m D 3

B

A

b

s

10 m 5 m 25 m

g vk = 77.1 kN/m

450 kN 450 kN

q vk = 45.65 kN/m

1.2 m

450 kN 450 kN

q vk = 45.65 kN/m

1.2 m 1.6

0. 4

0.352

-

+

0.952

1

1.6 3.57 m

1.43

Figure 4.186 Determination of the force in diagonal member D 3 using the influence
line method.

F Ed D ð maximum ¼ 925 : 1 1 : 3 + 1542 1 : 35

¼ 3284 : 3 kN Tension force ð Þ

F Ed D ð minimum ¼F D : L : g g + F L : L : g q

F Ed D ð minimum ¼ 925 : 1 1 : 3 492 : 6 1 : 35

¼ 537 : 6 kN Tension force ð Þ

4.6.3.8 Calculation of Force in the Diagonal Chord Member D 2
The force in the diagonal truss member D 2 can be calculated, as shown in
Figure 4.187 , as follows:

A ve D ðÞ¼ 0 : 5 34 : 29 1 : 2 ¼ 20 : 57

A +ve D ðÞ¼ 0 : 5 5 : 71 0 : 2 ¼ 0 : 57

A net D ðÞ¼ 20 : 57 + 0 : 57 ¼ 20 : 0

F D : L : D ðÞ¼ 20 77 : 1 ¼ 1542 kN

F L : L : D ðÞ negative ð Þ ¼ 450 1 ð : 2+1 : 152 Þ 20 : 57 45 : 65 7 : 5

0 ð : 2+0 : 152 Þ 0 : 57 2 : 45 ¼ 2001 : 5kN