B C1107 Pages 3

PART ‏تا‎
‎Answer any two full questions, each carries 15 marks.
4 லி Explain the following: (5)
i) Shear force and bending moment in a beam.

ii) Hogging and sagging moments.
ili) Point of contra flexure.
b) Determine the load P such that reactions at supports A and B are equal in the (19)

beam shown in fig3.Draw the shear force and bending moment diagrams and
mark the values at salient points.

~~ | பய

Fig3

5 ച What is meant by pure bending? Sketch an example of a beam subjected 10 (3)
pure bending.

b) A simply supported beam of length 3 m carries a point load of 12 KN ata (12)
distance of 2 m from left support. The cross section of the beam is as shown in
Fig.4 b.

௮2/20 ‏چپ‎

x ye" ॥ | 7 / ॐ,

ഈ നാ | 0 ks
5 | i

x x

|< 100 mn ‏ع‎

Fig 4 0)

Determine the bending stresses at extreme fibres at section X-X. Take moment
of inertia about neutral axis of the section as 2.56x107 mm‘.

6 a) Calculate the strain energy stored in a cantilever beam of length 2 m subjected (5)
10 a point load 10 kN at the free end. Take E = 200 GPa and I= 1.5x10’mm‘.

b) Calculate the moment of resistance of a composite beam made of wood and (10)
steel. The cross section is rectangular,with wood 150 mm wide and 300 mm
deep, strengthened by fixing steel plates of 12 mm thickness and 300 mm
deepth on either side.If the maximum stress in wood is 8 N/mm/?, what is the
corresponding maximum stress attained in steel?.Take 5५-10 GPa and Es=200
GPa.

Page 2 of 3