Civil Engineering Reference
In-Depth Information
W
2
W
1
w
A
B
C
2
W
1
L
BM due to
W
1
ve
m
1
L
L
A
B
C
(a)
(b)
2
wL
2
W
2
L
ve
m
3
BM due to
w
BM due to
W
2
ve
m
2
A
B
C
A
B
C
(c)
(d)
2
W
1
L
W
2
L
2
wL
2
Complete bending moment diagram
ve
m
1
m
2
m
3
A
B
C
(e)
F
IGURE
3.24
Bending moment (BM) diagram using the principle of superposition
PROBLEMS
P.3.1
A transmitting mast of height 40m and weight 4
.
5 kN/m length is stayed by three
groups of four cables attached to the mast at heights of 15, 25 and 35m. If each cable is
anchored to the ground at a distance of 20m from the base of the mast and tensioned
to a force of 15 kN, draw a diagram of the compressive force in the mast.
Ans.
Max. force
=
314.9 kN.
P.3.2
Construct the normal force, shear force and bending moment diagrams for the
beam shown in Fig. P.3.2.
Ans. N
AB
=
9
.
2kN,
N
BC
=
9
.
2kN,
N
CD
=
5
.
7kN,
N
DE
=
0.
S
AB
=−
6
.
9kN,
S
BC
=−
3
.
9kN,
S
CD
=+
2
.
2kN,
S
DE
=+
7
.
9kN
.
M
B
=
27
.
6kNm,
M
C
=
51 kNm,
M
D
=
40 kNm.
