Civil Engineering Reference
In-Depth Information
15,571.7 kN m
20,285.7 kN m
D
x
m
13.5 m
Figure 4.145 Calculation of curtailed flange plate lengths.
Length of Flange Plates
Assuming the overall bending moment diagram of the main plate girder is a
second-degree parabola (see
Figure 4.145
), we can determine the length of
the curtailed top flange plate of the upper and lower flanges as follows:
2
x
20,285
:
7
15,571
:
7
4714
20,285
¼
¼
7
¼
0
:
23238
L
=
2
20,285
:
7
:
x
13
5
¼
0
:
482; then,
x¼
6.5 m.
:
Hence, the length of the smaller top plate is 13 m.
4.5.5 Design of the Fillet Weld Between Flange Plates and Web
To determine the size of fillet weld connecting the bottom flange plates of
the upper and lower flanges with the web plate for the investigated bridge,
we can calculate the maximum shear flow at the support for the reduced
cross section, shown in
Figure 4.146
,
as follows:
6
270
3
12 + 2
54
3
3
5
2
Inertia about
y
-
y ¼
1
:
=
=
12 + 54
3
136
:
¼
8,661,492 cm
4
Shear flow at section
s
-
s
:
Q
Ed
S
ss
I
yy
q ¼
¼
2
a f
vw
,
d
p
b
w
g
M2
¼
f
u
=
=
p
430
30
mm
2
f
vw
,
d
¼
25
¼
233
:
=
7N
0
:
85
1
:
2
10
3
Þ
10
3
3327
:
54
3
136
ð
:
5
q ¼
¼
2
a
233
:
7
8,661,492
10
4
Then,
a¼
1.7 mm, taken as 8 mm, which is the minimum size.
Search WWH ::
Custom Search