Civil Engineering Reference
In-Depth Information
The plate thickness
t
3
can be calculated from the distribution of bending
moment, caused by the pressure on the concrete foundation, as follows:
M ¼
262,080Nmm per unit width of the plate
:
b
3
t
3
1
t
3
4
¼
0
:
25
t
2
mm
3
M
W
pl
¼
W
pl
¼
4
¼
f
y
g
M0
262,080
0
340
1
25
t
3
¼
0
:
:
4.3.3.34 Design of Hinged Line Rocker Steel Fabricated Bearings
Finally, we can now design the hinged line rocker steel fabricated bearings
shown in
Figure 4.36
and detailed in
Figure 4.91
.
The maximum vertical
reaction at the support of the main plate girder was previously calculated
under dead and live loads with dynamic effect (
R
D+L+
F
), which was
5822.2 kN. The bearing is also subjected to a lateral force from the braking
forces from traffic as well as subjected to a longitudinal force from the reac-
tions of the upper and lower wind bracings, which cause moments around
the longitudinal and lateral directions of the bearing base, respectively. Sim-
ilar to the roller bearing, the material of construction for the bearings is cast
iron steel (ISO 3755) 340-550 having a yield stress of 340 MPa and an ulti-
mate stress of 550 MPa. It should be noted that the overall height of the
hinged bearing must be exactly the same as that of the roller bearing. The
general layout and assumed dimensions of the hinged line rocker bearing
follows:
7
60
¼
522 kN, for Load model 1
See
Figure 4.91
for the direction of the forces. Also, the reactions from
forces) were previously calculated as follows:
R
tot
¼
2
460
Q
lbk
¼
360 + 2
:
7
L ¼
360 + 2
:
06 kN
We can now determine the normal stress distribution due to the applied
loads, shown in
Figure 4.91
, on the concrete foundation as follows:
:
53
¼
921
:
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