A doubly reinforced rectangular concrete beam has a width of 300 mm and an effective
depth of 500 mm. The beam is reinforced with 2200 mm2 of steel in tension and
628 mm2 of steel in compression. the effective cover for compression steel is 50 mm.
Assume that both tension and compression steel yield. The grades of concrete and steel
used are M20 and Fe250, respectively. The stress block parameters (rounded off to first
two decimal places) for concrete shall be as per IS 456 : 2000.
The moment of resistance of the section is
A. 206.00 kN-m
B. 209.20 kN-m
C. 236.80 kN-m
D. 251.90 kN-m
Answer : Option BExplaination / Solution: No Explaination.
Two beams PQ (fixed at P and with a roller support at Q, as shown in Figure I, which
allows vertical movement) and XZ (with a hinge at Y) are shown in the Figures I and II
respectively. The spans of PQ and XZ are L and 2L respectively. Both the beams are
under the action of uniformly distributed load (W) and have the same flexural stiffness,
EI (where, E and I respectively denote modulus of elasticity and moment of inertia
about axis of bending). Let the maximum deflection and maximum rotation be δmax1 and θmax1, respectively, in the case of beam PQ and the corresponding quantities
for the beam XZ be δmax2 and θmax2, respectively.
Which one of the following
relationships is true?
A. δmax1 ≠ δmax2 and θmax1 ≠ θmax2
B.
δmax1 = δmax2 and θmax1 ≠ θmax2
C. δmax1 ≠ δmax2 and θmax1 = θmax2
D. δmax1 = δmax2 and θmax1 = θmax2
Answer : Option DExplaination / Solution: No Explaination.
A rectangular concrete beam of width 120 mm and depth 200 mm is prestressed
by pre tensioning to a force of 150 kN at an eccentricity of 20 mm. The crosssectional
area of the prestressing steel is 87.5 mm2. Take modulus of elasticity of
steel and concrete as 2.1 × 105 MPa 3.0 × 104 MPa respectively. The percentage
loss of stress in the prestressing steel due to elastic deformation of concrete is
A. 8.75
B. 6.125
C. 4.81
D. 2.19
Answer : Option BExplaination / Solution: No Explaination.
In a pre-stressed concrete beam section shown in the figure, the net loss is 10% and the final prestressing
force applied at X is 750 kN. The initial fiber stresses (in N/mm2 ) at the top and bottom
of the beam were:
A. 4.166 and 20.833
B. –4.166 and –20.833
C. 4.166 and –20.833
D. –4.166 and 20.833
Answer : Option DExplaination / Solution:
Loss = 10%
The target mean strength fcm for concrete mix design obtained from the characteristic strength
fck and standard deviation σ, as defined in IS:456-2000, is
A. fck + 1.35σ
B. fck + 1.45σ
C. fck + 1.55σ
D. fck + 1.65σ
Answer : Option DExplaination / Solution: No Explaination.
Cross-section of a column consisting to two steel strips, each of thickness t and
width b is shown in the figure below. The critical loads of the column with perfect
bond and without bond between the strips are P and P0 respectively. The ratio
P/P0 is
A. 2
B. 4
C. 6
D. 8
Answer : Option BExplaination / Solution: No Explaination.