Civil Engineering Reference
In-Depth Information
Ans
. Influence line ordinates
(a) D
=−
0
.
125
L
,A
=
B
=
0, C
=
0
.
25
L
.
(b) D
=
E
=−
0
.
125
L
,A
=
B
=
0, C
=
0
.
25
L
.
P.20.4
The simply supported beam shown in Fig. P.20.4 carries a uniformly distributed
travelling load of length 10m and intensity 20 kN/m. Calculate the maximum positive
and negative values of shear force and bending moment at the section C of the beam.
Ans
.
S
C
=−
37
.
5 kN,
+
40
.
0kN
M
C
=+
550 kNm,
−
80 kNm.
A
C
B
D
8m
8m
4m
F
IGURE
P.20.4
P.20.5
The beam shown in Fig. P.20.5(a) is crossed by the train of four loads shown in
Fig. P.20.5(b). For a section at mid-span, determine the maximum sagging and hogging
bending moments.
Ans.
+
161
.
3kNm,
−
77
.
5kNm.
10
5
20
20 kN
C
2m
2m
2m
5 m
15 m
5 m
(a)
(b)
F
IGURE
P.20.5
P.20.6
A simply supported beam AB of span 20m is crossed by the train of loads
shown in Fig. P.20.6. Determine the position and magnitude of the absolute maximum
bending moment on the beam and also the maximum values of positive and negative
shear force anywhere on the beam.
Ans. M
(max)
=
466
.
7 kNm under a central load 10
.
5m from A.
S
(max
−
ve)
=−
104 kN at A,
S
(max
+
ve)
=
97
.
5kNatB.
50 kN
50 kN
30 kN
5m
4m
F
IGURE
P.20.6
