Design Examples of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 431

l 1 ¼ 93 : 9 0 : 924 ¼ 86 : 7636

5000
156

1

l¼

2 7636 ¼ 0

: 369

: 86 :

The axial compressive force in the upper chord member U 4
( N Ed ¼ 10,366.4 kN):

N Ed

N b , Rd 1

: 0

wAf y
g M1

where N b , Rd ¼

1
F +

w¼ p but w 1 : 0

l 2 F 2

h i

+ l 2

51+ a l 0 F¼ 0 : : 2

¼ 0

369 2 F¼ 0 : 51+0 : 34 0 ð : 369 0 : 2 Þ +0 : : 597

1

597 +

p

w¼ ¼ 0 : 938 but w 1 : 0

597 2 369 2

0 : 0 : 0 :

:

938 501,600 275
1 : 1

0

Then, N b , Rd ¼ ¼ 11,762,520N

N b , Rd ¼ 11762 : > N Ed ¼ 10366 : ð : : Þ

5kN 4 kN Then O K

4.6.3.13 Design of the Compression Upper Chord
Members U 2 and U 1
Following the same procedures adopted for the compression members U 4
and U 3 , we can design the compression upper chord members U 2 and
U 1 , shown in Figure 4.193 , carrying a compressive design force of
4846.8 kN. To classify the cross section chosen (see Figure 4.193 ) ,

s

235
f y

r

235
275

e ¼ ¼ ¼ 0 : 924

b ¼ 360mm, t fl ¼ 14, b = t fl ¼ 360 = 14 ¼ 25 : 7 < 30 : 5 Flange is Class 1 ð Þ

C ¼ 362mm, t w ¼ 14, C

= t fl ¼ 362 = 14 ¼ 25 : 9 < 30 : 5 Web is Class 1 ð Þ

4cm 2

A¼ 55 1 :

4+36 1

:

4+2 40 1

:

4 ¼ 232

:

50 1 : 4 20 : 7 36 1 : 4 16 : 9

e ¼ ¼ 2 : 57 cm

232 : 4