Design Examples of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 312

b = 40

2 y

x x

2

2

y

2

55 cm

Figure 4.82 The cross section of the lower chord tension member L 4 .

Figure 4.82 , carrying a tensile design force of 9773.9 kN. The design of
section can be as follows:

0 ¼ 370 cm 2 A¼A net ¼ 55 2 : 0+40 2 : 0+2 45 2 :

Af y
g M0 ¼

370 275 100
1

N pl , Rd ¼ ¼ 10,175,000N ¼ 1017 : 5kN > N Ed

: 0

¼ 9773 : 9kN

0 : 9 A net f u

g M2 ¼

0 : 9 370 100 430

1

N u , Rd ¼ ¼ 11,455,200N ¼ 11,455 : 2kN

:

25

> N Ed ¼ 9773 :

9kN

4.3.3.28 Design of the Lower Chord Member L 3
The lower chord member L 3 , shown in Figure 4.83 , carrying a tensile design
force of 7449.1 kN can be designed as follows:

6 ¼ 296 cm 2

A¼A net ¼ 55 1 :

6+40 1

:

6+2 45 1

:

Af y
g M0 ¼

296 100 275
1 : 0

N pl , Rd ¼ ¼ 8,140,000N ¼ 8140 kN > N Ed

¼ 7449 :

1kN

0 : 9 A net f u

g M2 ¼

0 : 9 296 100 430

1

N u , Rd ¼ ¼ 9,164,160N

: 25

¼ 9164 : > N Ed ¼ 7449 :

2kN 1kN