Design Examples of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 392

3600

F w

1800 1800 1800 1800 1800

9000 mm

Figure 4.152 Design heights for the calculation of wind forces on the lower wind
bracings.

R A R B

27 m

A s B

a
Fsin a
F

s

4.5 m

9 m

4.5 m

100 kN q WL = 20.86 kN/m

Figure 4.153 Loads on the lower wind bracing.

1
2 1

25 26 2

F w ¼ : 5 :

7 137

:

53 ¼ 331,208N ¼ 331

:

2kN

Considering the structural analysis for the lower wind bracing system
shown in Figure 4.153 , the critical design wind force in the diagonal bracing
members can be calculated as follows:

Distributed wind loads q WL ð Þ¼ 522 : 6 5 ð : 5 = 7 Þ= 30 ¼ 13 : 69 kN = m

Factored distributed wind loads ¼ q WL g q ¼ 13 : 69 1 : 7 ¼ 23 : 27 kN = m

R A ¼ 100 + 20 : 86 13 : 5 ¼ 381 : 6kN

a¼ tan 1 4 Þ 45 ð : 5 = 4 : 5