Design Examples of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 379

50

3

37.6

25.4

56.4

268.4

270 cm

1.6

54

Figure 4.142 Reduced cross-section of plate girder.

1 : 315 0 : 055 3 1 ð Þ

r¼ ¼ 0 : 697

:

315 2 1

2 ¼ 94 cm,
Then, b eff1 ¼ 0.6 94 ¼ 56.4 cm and b eff2 ¼ 0.4 94 ¼ 37.4 cm as shown
in Figure 4.142 .
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 4.143 , as follows:

b eff ¼ 0 :

633 270

=

4cm 2 A¼ 54 3 2+50 3 2 + 191 : 4 1 : 6+37 : 6 1 : 6 ¼ 990 :

50 3 1 : 5+54 3 4 : 5 + 191 : 4 1 : 6 101 : 7+37 : 6

1 : 6 257 : 2+54 3 277 : 5+50 3 280 : 5

y c ¼

990 : 4

y c ¼ 136 cm