Design Examples of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 383

C 1 ¼ 254mm, t fl ¼ 30, C 1 = t fl ¼ 254 = 30 ¼ 8 : 47 Class 2 ð Þ:

C 2 ¼ 2684mm, t w ¼ 16, C 1 = t fl ¼ 2684 = 16 ¼ 167 : 75 > 124 0 : 924

¼ 114 : 58 Class 4 ð Þ:

To calculate the bending moment resistance, the effective area should be
used. Considering web plate buckling, the effective area of the part of web
plate in compression (see Figure 4.144 ) can be calculated as follows:
k s ¼ 23 : 9

270 = 1 : 6

l p ¼

p

23

¼ 1 : 315 > 0 : 673

28 : 4 0 : 924 : 9

:

315 0

:

055 3 1

ð Þ

1

r¼ ¼ 0 : 697

:

315 2 1

b eff ¼ 0 :

697 270

=

2 ¼ 94 cm,

Then, b eff1 ¼ 0.6 94 ¼ 56.4 cm and b eff2 ¼ 0.4 94 ¼ 37.6 cm as shown
in Figure 4.144 .
To calculate the elastic section modulus, the elastic centroid of the sec-
tion has to be located by taking the first area moment, as an example, around
axis y 0 - y 0 shown in Figure 4.144 , as follows:

4cm 2

A¼ 54 3 2 + 191 : 4 1 : 6+37 : 6 1 : 6 ¼ 690 :

½ 54 3 1 : 5+ 191 : 4 1 : 6 98 : 7+37 : 6 1 : 6 254 : 2+54 3 274 : 5

y c ¼

690 : 4

y c ¼ 130 7cm

Inertia about y 1 - y 1 ¼ 54 3 3

:

2 2

½ =

12 + 54 3 129

:

+54 3 3 8 2 ½ = 12 + 54 3 143 :

4 3 4 32 2

+1 ½ : 6 191 : = 12 + 1 : 6 191 :

6 3 8 2 +1 ½ : 6 37 : = 12 + 1 : 6 37 : 6 143 :

¼ 8,227,509 cm 4

3cm 3 W eff , min ¼ 8,227,509 = 145 : 3 ¼ 56,624 :

Bending Moment Resistance

W eff , min f y
g M0

:

3 10 3

275

56,624

M c , Rd ¼ ¼ ¼ 15,571,700,000Nmm

:

1 0

¼ 15,571 : 7kNm