Design Examples of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 359

Design of the Rollers
The design of rollers requires determination of the diameter, length, and
number of rollers to resist the vertical load as well as the arrangement and
allowed movement in the direction of rollers. The design axial force per
unit length of roller contact N Sd

specified in BS EN 1337-1 [3.11] shall

satisfy

N

Sd N Rd

where N Rd is the design value of resistance per unit length of roller contact,

which is calculated as

f u 550 2

210,000

1
g 2 m ¼ 23 R

1
1 ¼ 33

N

Rd ¼ 23 R

E d

: 131 R

Assume the number of rollers is 2 and their length is 800 mm as shown in
Figure 4.33 :

36 10 3
1800

R D+L+ F 2193 :

N

Sd ¼

2 900 ¼

¼ 1218 : 5N = mm

Then, the radius of rollers can be determined by equalizing N Sd with

N Rd as follows:

131 R
Then, R¼ 37.7 mm, taken as 50 mm and the diameter D is 100 mm.

1218 : 5 ¼ 33 :

Design of Upper Bearing Plate
The upper bearing plate is shown in Figure 4.123 . The width and length of
the plate are dependent on the spacing between rollers and the length of rol-
lers as well as the allowed movement in the direction of rollers. The thick-
ness of the upper bearing plate can be determined as follows:

R D+L+ F
2

ð D + 100 Þ :

36 10 3
2

2193 200

2 ¼ 109,668,000N mm

M ¼ ¼ :

2

b 2 t 2

900 t 2

4 ¼ 225 t 2 mm 3
The plate thickness t 2 can be calculated now as follows:
M
W pl ¼

W pl ¼

4 ¼

f y
g M0