Design Examples of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 373

in the compression flange of the main plate girder ( F max ) multiplied by the
arm ( r ). The maximum force can be calculated as follows ( Figure 4.136 ) :

M Ed M ð : G : Þ 20285 : 7

99 270 ¼ 7589 kN
Additional bending moment ¼ 7589

F max ¼ ¼

y ct :

0

ð = 100 Þ 2 : 2306 ¼ 169 : 3kNm

Design Bending Moment (M Ed ) and Shear Force (Q Ed )
M Ed ¼M D+L+ F ¼ 3570 : 1 + 169 : 3 ¼ 3739 : 4kNm

Q Ed ¼Q D+L+ F ¼ 1325 kN

Design of the Cross Girder Cross Section

W pl f y
g M0

M c , Rd ¼ for classes 1 and 2

W pl 275
1

4 10 6 3739 : ¼

: 0

8cm 3
Choose UB 914 419 343 (equivalent to American W36 230),
shown in Figure 4.137 . W PL around x - x¼ 15,480 cm 3 . To classify the cross
section chosen,

W PL ¼ 13,597,818mm 3 ¼ 13,597 :

s

235
f y

r

235
275

e ¼ ¼ ¼ 0 : 924

F = 1/100 F max in the main
girder compression flange

F

r = 223.06 cm

91.19 cm

Figure 4.136 Additional bending moment on cross girders due to flexibility of the
U-frame.