Design Examples of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 357

Flange Splices

Maximum force in the upper flange ¼ 150 275 100

=

1000 ¼ 4125 kN

N flange ð Þ 4125 = 206 ¼ 20 bolts 5 rows of four bolts in double shear ð Þ

Maximum force in the lower flange ¼ 210 275 100 = 1000 ¼ 5775 kN

N flange ð Þ 5775 206

¼ 28 taken as 30 bolts 5 rows of six bolts in double shear

=

ð Þ

4.4.6 Design of Roller Steel Fabricated Bearings
Let us now design the roller steel fabricated bearings shown in Figure 4.106
and detailed in Figure 4.123 . The maximum vertical reaction at the supports
of the main plate girder was previously calculated under dead and live loads
with dynamic effect ( R D+L+ F ), which was 2193.36 kN. The material of
construction for the bearings is cast iron steel (ISO 3755) 340-550 having
a yield stress of 340 MPa and an ultimate stress of 550 MPa.

Design of the Sole Plate
The reaction ( R D+L+ F ) can be assumed as two equal concentrated loads at
two points, which are the centers of gravity of half of the load bearing stiff-
ener section shown in Figure 4.123 . To determine the centers of gravity
(distance e ), we can take the first area moment around the axis z - z , shown
in Figure 4.33 , as follows:

2 25 1 : 0 0 : 5+23 : 0 1 : 6 11 : 5

e ¼ ¼ 5 : 16 cm

2 25 1 : 0+23 : 0 1 : 6

Assuming that the thickness of the sole plate is t 1 , with detailed dimensions
shown in Figure 4.33 based on the flange plate girder dimensions, we can
determine the maximum moment applied to the sole plate ( M ) as follows:

36 10 3 M ¼R D+L+ F e = 2 ¼ 2193 : 51 : 6 = 2 ¼ 56,588,688Nmm :

¼ b 1 t 1 =

4 ¼ 200 t 1
The plate thickness t 1 can be calculated now as follows:
M
W pl ¼

4 ¼ 800 t 1 = Section plastic modulus W pl

f y
g M0
56,588,688
200 t 1 ¼

340
1

0
Then, t 1 ¼ 28.8 mm, taken as 40 mm, as shown in Figure 4.123 .

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