Design Examples of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 317

Factored distributed wind loads ¼ q WL g q ¼ 9 : 03 1 : 7 ¼ 15 : 351 kN = m

R A ¼ 15 : 351 60 = 2 ¼ 460 : 53 kN

a¼ tan 1 6 ðÞ¼ 45 =

6kN
The cross section of the bracing member (see Figure 4.28 ) can be
determined as follows:
l b x ¼ 8490mm,

F D ¼ 460 : 53 = ð 2 sin45 Þ ¼ 325 :

l b y ¼ 1 : 2 8490 ¼ 10,190mm

Choose two angles back-to-back 150 150 15, with 10 mm gusset plate
between them ( Figure 4.89 ) :

4cm 2 , A¼ 2 43 : 2 ¼ 86 : i x ¼ 4 : 59 cm, e ¼ 4 : 26 cm,

q

4

2

59 2 +4 i y ¼ : ð : 26 + 1 = 2 Þ ¼ 6 : 61 cm

r

235
275

e ¼ ¼ 0 : 924

L cr
i

1
l 1

l¼

l 1 ¼ 93 : 9 0 : 924 ¼ 86 : 7636

8490
45

1

l¼

7636 ¼ 2

: 13

: 9 86 :

The axial compressive force in the diagonal bracing member
( N Ed ¼ 325.6 kN):

R A

R B

60 m

B

A

q WL = 15.35 kN/m
Figure 4.89 Loads on the lower wind bracing.