Structural Engineering

Structural Engineering

Structural Engineering
| Structural Engineering |
Q.1
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 B
Explaination / Solution:
No Explaination.


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Q.2
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 D
Explaination / Solution:
No Explaination.


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Q.3
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 B
Explaination / Solution:
No Explaination.


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Q.4
The degree of static indeterminacy of rigidity jointed frame in a horizontal plane and subjected to vertical load only, as shown in figure below, is

A. 6
B. 4
C. 3
D. 1
Answer : Option C
Explaination / Solution:
No Explaination.


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Q.5
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 D
Explaination / Solution:

Loss = 10% 
Find force = 750 kN  
Initial force = 750/0.9 = 833.33kN
Top & Bottom stress = P/A ± m/z

Top = -4.166 (T) 
Bottom = 20.833 (C) 

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Q.6
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 D
Explaination / Solution:
No Explaination.


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Q.7
A reinforced concrete structure has to be constructed along a sea coast. The minimum grade of concrete to be used as per IS : 456-2000 is
A. M 15
B. M 20
C. M 25
D. M 30
Answer : Option D
Explaination / Solution:
No Explaination.


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Q.8
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 B
Explaination / Solution:
No Explaination.


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Q.9
Maximum possible value of compaction factor for fresh (green) concrete is
A. 0.5
B. 1.0
C. 1.5
D. 2.0
Answer : Option B
Explaination / Solution:
No Explaination.


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Q.10
Two geometrically identical isolated footings, X (linear elastic) and Y (rigid), are loaded identically (shown alongside). The soil reactions will




A. be uniformly distributed for Y but not for X
B. be uniformly distributed for X but not for Y
C. be uniformly distributed for both X and Y
D. not be uniformly distributed for both X and Y
Answer : Option A
Explaination / Solution:
No Explaination.


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