Design Examples of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 442

h i

+ l 2

51+ a l 0 F¼ 0 : : 2

¼ 0

764 2 F¼ 0 : 51+0 : 49 0 ð : 764 0 : 2 Þ +0 : : 888

1

w¼

888 +

p ¼ 0 : 746 but w 1 : 0

888 2 764 2 0 : 0 : 0 :

0 : 746 27,600 275

1

Then, N b , Rd ¼ ¼ 5,147,400N

: 1

N b , Rd ¼ 5147 : 4kN > N Ed ¼ 4706 : 6 kN ThenO ð : K : Þ

4.6.3.21 Design of the Compression Diagonal Member D 4
The diagonal compression members D 4 , shown in Figure 4.203 , carrying
a compressive design force of 1935.7 kN can be designed as follows.
To classify the cross section chosen (see Figure 4.203 ) ,

s

235
f y

r

235
275

e ¼ ¼ ¼ 0 : 924

C 1 ¼ 115mm, t fl ¼ 26, C 1 = t fl ¼ 115 = 26 ¼ 4 : 4 < 30 : 5 Flange is Class 1 ð Þ

C 2 ¼ 292mm, t w ¼ 14, C 2 = t fl ¼ 292 = 14 ¼ 20 : 9 < 30 : 5 Web is Class 1 ð Þ

32 cm 2

A¼ 2 26 2 : :

8 1

:

4 ¼ 178

:

6+30

¼ 48,731 cm 4

8 3 6 26 3 7 2

I x ¼ 1 : 4 30 : = 12 + 2 2 : = 12 + 2 : 6 26 16 :

6 26 3 4 3 12 ¼ 7623 cm 4 I y ¼ 2 2 : = 12 + 30 : 8 1 : =

r

I x
A

r

48,731
178

i x ¼ ¼ ¼ 16 : 53 cm

: 32

26 cm

y

2.6

x x

1.4

2.6

y

Figure 4.203 The cross section of the diagonal compression member D 4 .