Civil Engineering Reference
In-Depth Information
moments due to Cooper's E80 load is outlined in Examples 5.1 and 5.2.
Example 5.1
Determine the maximum bending moment per rail for Cooper's E80 load on
a 60 ft long deck plate girder (DPG) span. The moment at the center, C, is
assumed to be near the maximum bending moment in both location and
magnitude.
A review of the Cooper's load configuration indicates that the maximum
moment will likely occur under axles,
NP
=
3, 4, 5, 12, 13, or 14 (
Figure E5.1).
With
NP
=
3 (Cooper's load configuration wheel number 3)
From Table 5.1:
x
1
=
(S
1
)
3
=
13 ft
since
x
1
≤
L/
2
≤
30 ft; N1
=
1
support B is
(L/
2
+
x
1
)
=
30
+
13
=
43 ft from N1
since
(S
1
)
8
=
43 ft,
NL
=
8 and is over support B
xL
0
NE
is the last wheel on the span and is equal to
NL
=
43-43
=
−
1
=
7 when
NL
is over
support B
M
(
NL
−
1
)
,N1
+
P
N1,NE
(xL)
60
M
7,1
+
P
1,7
(xL)
60
M
B
L
R
B
=
=
=
5702
+
232
(
0
)
60
=
=
95.03 kips,
M
(
NP−1
)
,N1
=
M
2,1
M
C
=
R
B
(L/
2
)
−
R
B
(L/
2
)
−
=
95.03
(
30
)
−
460
=
2391 ft-kips.
©
NP
NL
N1
C
A
B
x
1
xL
L
/2
L
/2
FIGURE E5.1