Deck 3: Design and Reinforcement of Concrete Structures

Question 1

If the shear stress in a R.C.C. beam is

A)Equal or less than 5 kg/cm², no shear reinforcement isprovided
B)Greater than 4 kg/cm², but less than 20 kg/cm², shear reinforcement is provided
C)Greater than 20 kg/cm², the size of the section ischanged
D)All the above

Answer 1

All the above

Question 2

The ratio of the breadth to effective depth of a beam is kept

A)0.25
B)0.50
C)0.70
D)0.75

Answer 2

0.50

Question 3

In a cantilever retaining wall without a heel slab

A)Thickness ofthe stem is keptsame throughout
B)Base slab is made 10 cm thicker than the stem
C)Width of the base slab is kept 0.7 time the total height of the wall
D)All the above

Answer 3

All the above

Question 4

is the pre-stressed force applied to the tendon of a rectangular pre-stressed beam whose area of cross section is and sectional modulus is . The maximum stress in the beam, subjected to a maximum bending moment , is

A)f = (P/A) +(Z/M)
B)f = (A/P) +(M/Z)
C)f = (P/A) + (M/Z)
D)f = (P/A) + (M/6Z)

Question 5

A reinforced concrete cantilever beam is 3.6 m long, 25 cm wide and has its lever arm 40 cm. It carries a load of 1200 kg at its free end and vertical stirrups can carry 1800 kg. Assuming concrete to carry one-third of the diagonal tension and ignoring the weight of the beam, the number of shear stirrups required, is

A)30
B)35
C)40
D)45

Question 6

To ensure that the hogging bending moment at two points of suspension of a pile of length L equals the sagging moment at its centre, the distances of the points of suspension from either end, is

A)0.107 L
B)0.207 L
C)0.307 L
D)0.407L

Question 7

The stresses developed in concrete and steel in reinforced concrete beam 25 cm width and 70 cm effective depth, are 62.5 kg/cm² and 250 kg/cm² respectively. If m = 15, the depth of its neutral axis is

A)20 cm
B)25 cm
C)30 cm
D)35 cm

Question 8

If the modularratio is , steel ratio is and overalldepth of a beam is , the depth ofthe critical neutral axis of the beam, is

A)[m/(m - r)] d
B)[m/(m + r)] d
C)[(m + r)/m] d
D)[(r - m)/m] d

Question 9

According to the steel beam theory of doubly reinforced beams

A)Tension is resisted by tension steel
B)Compression is resisted by compression steel
C)Stress in tension steel equals the stress in compressionsteel
D)All the above

Question 10

The breadth of a ribbed slab containing two bars must be between

A)6 cm to 7.5 cm
B)8 cm to 10 cm
C)10 cm to 12 cm
D)12 cm to 15 cm

Question 11

The stem of a cantilever retaining wall which retains earth level with top is 6 m. If the angle of repose and weight of the soil per cubic metre are 30° and 2000 kg respectively, the effective width of the stem at the bottom, is

A)51.5
B)52.5
C)53.5
D)54.5

Question 12

For a number of columns constructed in a rcjw, the type of foundation provided, is

A)Footing
B)Raft
C)Strap
D)Strip

Question 13

A singly reinforced concrete beam of 25 cm width and 70 cm effective depth is provided with 18.75 cm² steel. If the modular ratio (m) is 15, the depth of the neutral axis, is

A)20 cm
B)25 cm
C)30 cm
D)35 cm

Question 14

In testing a pile by load test, pile platform is loaded with one and half times the design load and a maximum settlement is noted. The load is gradually removed and the consequent rebound is measured. For a safe pile, the net settlement (i.e. total settlement minus rebound) per tonne of test load should not exceed

A)10 mm
B)15 mm
C)20 mm
D)25 mm