Civil Engineering Reference
In-Depth Information
The
resultant
of
the
forces
per
bolt
(
R
)
is
equal
to
p
139
5
2
+ 143
9
2
4 kN, which is less than 206 kN (the resistance
of the bolt in double shear). Then O.K.
:
:
¼
200
:
Flange Splices
Maximum force in the upper flange
¼
162
275
100
=
1000
¼
4455 kN
N
flange
ð
Þ ¼
4455
=
206
¼
21
:
6 bolts 6 rows of four bolts in double shear
ð
Þ
4.5.13 Design of Roller Steel Fabricated Bearings
Let us now design the roller steel fabricated bearings shown in
Figure 4.126
and detailed in
Figure 4.159
.
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 3132.8 kN. The material of con-
struction 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 4.159
. To determine the centers of gravity
(distance
e
), we can take the first area moment around the axis
z
-
z
, shown
in
Figure 4.159
, as follows:
2
25
1
:
2
0
:
6+23
:
2
1
:
6
11
:
6
466
:
592
e ¼
¼
12
¼
4
:
8cm
2
25
1
:
2+23
:
2
1
:
6
97
:
Assuming that the thickness of the sole plate is
t
1
, with detailed dimensions
shown in
Figure 4.159
based on the flange plate girder dimensions, we can
determine the maximum moment applied to the sole plate (
M
) as follows:
8
10
3
M ¼R
D+L+
F
e
=
2
¼
3132
:
48
=
2
¼
75,187,200Nmm
:
¼ b
1
t
1
=
4
¼
175
t
1
The plate thickness
t
1
can be calculated now as follows:
M
W
pl
¼
4
¼
700
t
1
=
Section plastic modulus
W
pl
f
y
g
M0
75,187,200
175
t
1
¼
340
1
0
:
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