Deck 5: Concrete Beam and Structural Design

Question 1

The angle of repose of a soil is the maximum angle which the outer face of the soil mass makes

A)With the horizontal
B)With the vertical
C)With the perpendicular to the inclined plane of the soil
D)None of these

Answer 1

With the horizontal

Question 2

In a doubly-reinforced beam if and is the effective depth and is depth of critical neutral axis, the following relationship holds good

A)mc/t = n/(d - n)
B)(m + c)/t = n/(d + n)
C)(t + c)/n = (d + n)/n
D)mc/t = (d - n)/t

Answer 2

mc/t = n/(d - n)

Question 3

A raft foundation is provided if its area exceeds the plan area of the building by

A)10 %
B)20 %
C)40 %
D)50%

Answer 3

50%

Question 4

In favourable circumstances a 15 cm concrete cube after 28 days, attains a maximum crushing strength

A)100 kg/cm²
B)200 kg/cm²
C)300 kg/cm²
D)400 kg/cm²

Question 5

If p₁ is the vertical intensity of pressure at a depth h on a block of earth weighing w per unit p² is

A) wh(1?cos?)/(1+sin?)
B) wh(1?sin?)/(1+sin?)
C) wh(1?tan?)/(1+tan?)
D) w(1?sin?)/h(1+sin?)

Question 6

Pick up the incorrect statement from the following. The intensity of horizontal shear stress at the elemental part of a beam section, is directly proportional to

A)Shear force
B)Area of the section
C)Distance of the C.G. of the area from its neutralaxis
D)Moment of the beam section about its neutral axis

Question 7

According to I.S.: 456, 1978 the thickness of reinforced concrete footing on piles at its edges, is kept less than

A)20 cm
B)30 cm
C)40 cm
D)75 cm

Question 8

An R.C.C. beam of 25 cm width and 50 cm effective depth has a clear span of 6 metres and carries a U.D.L. of 3000 kg/m inclusive of its self weight. If the lever arm constant for the section is 0.865, the maximum intensity of shear stress, is

A)8.3 kg/cm²
B)7.6 kg/cm²
C)21.5 kg/cm²
D)11.4 kg/cm²

Question 9

The percentage of minimum reinforcement of the gross sectional area in slabs, is

A)0.10 %
B)0.12 %
C)0.15 %
D)0.18%

Question 10

If the permissible compressive stress for a concrete in bending is C kg/m² , the modular ratio is

A)2800/C
B)2300/2C
C)2800/3C
D)2800/C²

Question 11

An R.C.C. beam not provided with shear reinforcement may develop cracks in its bottom inclined roughly to the horizontal at

A)25°
B)35°
C)45°
D)55°

Question 12

Cantilever retaining walls can safely be used for a height not more than

A)3 m
B)4 m
C)5 m
D)6 m

Question 13

The maximum area of tension reinforcement in beams shall not exceed

A)0.15 %
B)1.5 %
C)4 %
D)1 %

Question 14

The width of the flange of a T-beam should be less than

A)One-third of the effective span of the T-beam
B)Distance between the centres of T-beam
C)Breadth of the rib plus twelve times the thickness of the slab
D)Least of theabove

Question 15

For a circular slab carrying a uniformly distributed load, the ratio of the maximum negative to maximum positive radial moment, is

A)1
B)2
C)3
D)5

Question 16

According to I.S. : 456 specifications, the safe diagonal tensile stress for M 150 grade concrete, is

A)5 kg/cm²
B)10 kg/cm²
C)15 kg/cm²
D)20 kg/cm²

Question 17

The width of the flange of a T-beam, which may be considered to act effectively with the rib depends upon

A)Breadth of the rib
B)Overall thickness of the rib
C)Centre to centre distance between T-beams
D)All the above

Question 18

The maximum shear stress (qmax) in a rectangular beam is

A)1.25 times the average
B)1.50 timesthe average
C)1.75 timesthe average
D)2.0 times theaverage

Question 19

If K is a constant depending upon the ratio of the width of the slab to its effective span l, x is the distance of the concentrated load from the nearer support, bw is the width of the area of contact of the concentrated load measured parallel to the supported edge, the effective width of the slab be is

A)K/x (1 + x/d) + bw
B)Kx (1 - x/l) + bw
C)Kx (1 + x/l) + bw
D)All the above

Question 20

The length of the straight portion of a bar beyond the end of the hook, should be at least

A)Twice thediameter
B)Thrice thediameter
C)Four times the diameter
D)Seventimes the diameter

Question 21

If the maximum bending moment of a simply supported slab is M Kg.cm, the effective depth of the slab is (where Q is M.R. factor)

A) $\frac{{\text{M}}}{{10\sqrt {\text{Q}} }}$

B) $\frac{{\text{M}}}{{10\sqrt {\text{Q}} }}$ .

C) $\sqrt {\frac{{\text{M}}}{{\text{Q}}}}$ .

D) $\sqrt {\frac{{\text{M}}}{{100{\text{Q}}}}}$

Question 22

If is the overall height of a retaining wall retaining a surcharge, the width of the base slab usually provided, is

A)0.3 H
B)0.4 H
C)0.5 H
D)0.7 H