Design Examples of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 292

It should be noted that the design force of member U 4 is close to that
of this designed member U 5 ; therefore, we can use the same cross section
for U 4 .

4.3.3.14 Design of the Compression Upper Chord Member U 3
Following the same procedures adopted for the compression member
U 5 , we can design the compression upper chord member U 3 , shown in
Figure 4.68 , carrying a compressive design force of 9773.9 kN. To classify
the cross section chosen (see Figure 4.67 ) ,

s

235
f y

r

235
275

e ¼ ¼ ¼ 0 : 924

b ¼ 400mm, t fl ¼ 30, b = t fl ¼ 400 = 33 ¼ 13 : 3 < 30 : 5 Flange is Class 1 ð Þ

C ¼ 396mm, t w ¼ 20, C = t fl ¼ 396 = 20 ¼ 19 : 8 < 30 : 5 Web is class 1 ð Þ

0 ¼ 465 cm 2 A¼ 55 3 : 0+40 3 : 0+2 45 2 :

55 3 : 0 24 : 0 40 3 : 0 18 : 6

e ¼ ¼ 3 : 72 cm

465

0 45 3 0 3 0 2 I m ¼ 2 2 : = 12 + 55 3 : = 12 + 55 3 : 6 24 :

¼ 167,143

0 3 6 2 95 cm 4 +40 3 : = 12 + 40 3 : 0 18 : :

72 2 1cm 4 I x ¼ 167,143 : 95 565 3 : ¼ 160,709 :

55 cm

3.0

e = 3.72

C = 39.6

x

x

h w = 45

m

m

2.0

2.0

3.0

2 .4

Gusset plate

b = 40

Figure 4.68 The cross section of the compression member U 3 .