Design Examples of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 393

1kN
The cross section of the bracing member (see Figure 4.154 ) can be deter-
mined as follows:

F D ¼ 281 : 6 = ð 2 sin45 Þ ¼ 199 :

2 6360 ¼ 7632mm
Choose two angles back-to-back 150 150 15, with 10 mm gusset
plate between them:

l b x ¼ 6360mm, l b y ¼ 1 :

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

6360
45

1

l¼

7636 ¼ 1

: 597

: 9 86 :

The axial compressive force in the diagonal bracing member
( N Ed ¼ 298.7 kN):

N Ed

N b , Rd 1

: 0

wAf y
g M1

where N b , Rd ¼

4cm 2 A¼ 2 43 : 2 ¼ 86 :

e = 42.6 mm

y

x x

2 angles back-to-back
150×150×15

10 mm

y

Figure 4.154 Upper wind bracing cross section s-s.