Design Examples of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 434

and net cross-sectional areas of the lower chord members are the same since
they are connected using butt weld. The design of section can be performed
as follows:

6cm 2

A¼A net ¼ 50 2 : 6+36 2 : 2+2 40 2 : 6 ¼ 431 :

Af y
g M0 ¼

431 : 6 275 100

1

N pl , Rd ¼ ¼ 11,869,000N ¼ 11869 kN > N Ed

: 0

¼ 11039 : 3kN

0 : 9 A net f u

g M2 ¼

0 : 9 431 : 6 100 430

1

N u , Rd ¼ ¼ 13,362,336N

: 25

¼ 13,362 : 3kN > N Ed ¼ 11,039 : 3kN

4.6.3.15 Design of the Lower Chord Members L 3 and L 2
Following the same procedures adopted for the design of the lower chord
members L 5 and L 4 , we can design the tensile lower chord members L 3
and L 2 , shown in Figure 4.195 , carrying a tensile design force of
8302.3 kN. The design of section can be as follows:

0 ¼ 332 cm 2 A¼A net ¼ 50 2 : 0+36 2 : 0+2 40 2 :

Af y
g M0 ¼

332 275 100
1

N pl , Rd ¼ ¼ 9,130,000N ¼ 9130 kN > N Ed

:

0

¼ 8302 : 3kN

0 : 9 A net f u

g M2 ¼

0 : 9 332 100 430

1

N u , Rd ¼ ¼ 10,278,720N ¼ 10,278 : 7kN

: 25

> N Ed ¼ 8302 kN

b = 36 cm

2 y

x x

2

2

y

2

50 cm

Figure 4.195 The cross section of the lower chord tension member L 3 and L 2 .