Theory Of Structures MCQ Questions & Answers

21

If a concrete column 200 × 200 mm in cross-section is reinforced with four steel bars of 1200 mm² total cross-sectional area. Calculate the safe load for the column if permissible stress in concrete is 5 N/mm² and E_s is 15 E_c

A) 264 MN B) 274 MN C) 284 MN D) 294 MN

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Answer & Solution

Answer: Option C

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22

Slenderness ratio of a long column, is

A) Area of cross-section divided by radius of gyration B) Area of cross-section divided by least radius of gyration C) Radius of gyration divided by area of cross-section D) Length of column divided by least radius of gyration

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Answer & Solution

Answer: Option D

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23

The ratio of the area of cross-section of a circular section to the area of its core, is

A) 4 B) 8 C) 12 D) 16

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Answer & Solution

Answer: Option D

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24

A truss containing j joints and m members, will be a simple truss if

A) m = 2j - 3 B) j = 2m - 3 C) m = 3j - 2 D) j = 3m - 2

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Answer & Solution

Answer: Option A

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25

For beams breadth is constant,

A) Depth $${\text{d}} \propto {\text{M}}$$ B) Depth $${\text{d}} \propto \sqrt {\text{M}} $$ C) Depth $${\text{d}} \propto 3\sqrt {\text{M}} $$ D) Depth $${\text{d}} \propto \frac{1}{{\text{M}}}$$

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Answer & Solution

Answer: Option B

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26

Flat spiral springs

A) Consist of uniform thin strips B) Are supported at outer end C) Are wound by applying a torque D) All the above

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Answer & Solution

Answer: Option D

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27

The ratio of lateral strain to axial strain of a homogeneous material, is known

A) Yield ratio B) Hooke’s ratio C) Poisson’s ratio D) Plastic ratio

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Answer & Solution

Answer: Option C

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28

A steel rod of sectional area 250 sq. mm connects two parallel walls 5 m apart. The nuts at the ends were tightened when the rod was heated to 100°C. If α_steel = 0.000012/C°, E_steel = 0.2 MN/mm², the tensile force developed at a temperature of 50°C, is

A) 80 N/mm² B) 100 N/mm² C) 120 N/mm² D) 150 N/mm²

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Answer & Solution

Answer: Option C

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29

In case of principal axes of a section

A) Sum of moment of inertia is zero B) Difference of moment inertia is zero C) Product of moment of inertia is zero D) None of these

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Answer & Solution

Answer: Option C

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30

A close coil helical spring when subjected to a moment M having its axis along the axis of the helix

A) It is subjected to pure bending B) Its mean diameter will decrease C) Its number of coils will increase D) All the above

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Answer & Solution

Answer: Option A

Solution:

A close coil helical spring is designed primarily to resist axial loads, but when a moment is applied along the axis of the helix, it behaves differently.

In this case, the axial moment causes each coil to bend rather than twist or compress.

This results in pure bending of the spring wire, without torsion or axial compression/stretching.

Option B: Its mean diameter will decrease – Not true in this scenario; there is no significant radial compression due to moment.

Option C: Its number of coils will increase – This is incorrect; the number of coils is fixed and does not change with loading.

Therefore, only Option A is correct, as the spring is subjected to pure bending under the applied moment.

Theory Of Structures MCQ Questions & Answers | Civil Engineering