This set of Strength of Materials Multiple Choice Questions & Answers (MCQs) focuses on “Combined Stress”.
1. Bond stress for M20 grade concrete in tension is ____________
Explanation: Bond stress is the shear stress acting parallel to the bar on the interface between the reinforcing bar and the surrounding concrete. Hence it is the stress developed between the contact surface of Steel and concrete to keep them together. The value of M20 designs Bond stress is 1.2 in tension.
2. The formation of diagonal cracks at junctions is due to ________
a) Shear stress
b) Bond stress
c) Temperature stress
d) Lateral stress
Explanation: Bending is usually accompanied by shear. The combination of shear and bending stresses produces the principle stresses which causes diagonal tension in the beam section. This should be resisted by providing shear reinforcement in the form of vertical stirrups (or) bent up bars along with stirrups.
3. Calculate the factored bending moment of a rectangular reinforced concrete beam of effective span 4300 mm and load imposed 37.5 kN/m.
Explanation: Factored load (w) = 1.5×37.5 = 56.25 kN/m.
Factored bending moment for simply supported beam (M) = wl2/ 8. = 56.25×(4.3)2/ 8 = 130kNm.
4. Determine the limiting percentage of steel for singly reinforced sections of M20 grade & Fe415.
Explanation: The limiting percentage of steel for singly reinforced sections of M20 grade & Fe415 is 0.96.
|Grade of Concrete||Limiting Percentage of Tensile Steel for a Fe415|
5. Calculate the limiting depth of the neutral axis for mild steel of effective depth 400 mm.
Explanation: The limiting depth of neutral axis Fe 250 steel is
Xu (max) = 0.53 × d ( for Fe250)
= 0.53 × 400
6. Lap splices should not be used for bars larger than _____ mm.
Explanation: Splices are provided when the length of the bar is less than that required. The splicing of reinforcement is provided either by lap joint or mechanical joint or welded Joint. Lap splices should not be used for bars larger than 36 mm for larger diameter, bars may be welded.
7. Anchorage value for “U” hook is ________
a) 16 × diameter of bar
b) 12 × diameter of bar
c) 10 × diameter of bar
d) 8 × diameter of bar
Explanation: Anchorage value for “U” hook is 16 × diameter of bar.
|Type of Hook / Bend in Degrees||Anchorage Value|
|U hook||16 × diameter of bar|
|45 bend||4 × diameter of bar|
|90 bend||8 × diameter of bar|
|135 bend||12 × diameter of bar|
8. The standard __________ are provided in deformed bars.
Explanation: In situations, where straight anchorage length cannot be provided due to lack of space. To improve the anchorage of bars, standard bends are provided in deformed bars.
9. Transverse bars are also called as _________
a) Main bars
b) Anchor bars
c) Distribution bars
Explanation: In addition to main bars, along the shorter direction provided at the bottom, minimum reinforcement along the longer span and are also provided on top of the main bars and at right angles to them. These are called distribution bars are transverse bars.
10. A slab supporting only in two edges opposite to each other is ______
a) Two way slab
b) One way slab
c) Continuous slab
d) Cantilever slab
Explanation: If the ratio of the longest span the shorter span is greater than 2 or A slab supporting only in two edges (opposite to each other) is called one way slab. This slab spans across shorter span practically.
11. Torsion reinforcement is provided in ___________ slab
a) One way slab
b) Two way slab
c) Simply supported slab
d) Cantilever slab
Explanation: A slab supporting on all four edges is known as two way slab. In this slab, the ratio of longest span to the shorter span is less than 2. It requires torsional reinforcement because there’s a chance of twisting at corners.
12. Generally in residential buildings, the width of stay is kept as ____________
Explanation: The stair consists of series of steps with landings at appropriate intervals. The width of stair depends upon the type of building in which it is provided. Generally, in residential buildings, the width of stair is 1 m.
13. As per IS 456:2000; the slope or pitch of stairs should be in between 25 ° to ___________
Explanation: Each step has one tread and one rise. As per IRC, the tread is in between 250mm to 300 mm. The slope or pitch of the stairs should be in between 25° to 40°.
14. When space is less, the ___________ staircases is much preferred.
a) Open well
b) Dog legged
c) Spiral stair
Explanation: The most common type of Stairs arranged with two adjacent flights running parallel with mid landing. Where the space is less, dog legged staircase is generally provided resulting in economical utilisation of available place.
15. The ______________ of a column is the distance between the points of zero bending moments.
a) Slenderness ratio
c) Radius of gyration
d) Effective length
Explanation: Effective length of a column is the distance between the points of zero bending moments (point of contra flexure) of a buckled column the effective length of the column depends upon the unsupported length and the end conditions.
Sanfoundry Global Education & Learning Series – Strength of Materials.
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