Deck 6: Concrete Design and Structural Analysis

Question 1

The minimum cube strength of concrete used for a pre-stressed member, is

A)50 kg/cm²
B)150 kg/cm²
C)250 kg/cm²
D)350 kg/cm²

Answer 1

350 kg/cm²

Question 2

If d and n are the effective depth and depth of the neutral axis respectively of a singly reinforced beam, the lever arm of the beam, is

A)d
B)n
C)d + n/3
D)d - n/3

Answer 2

d - n/3

Question 3

An R.C.C. column of 30 cm diameter is reinforced with 6 bars 12 mm placed symmetrically along the circumference. If it carries a load of 40, 000 kg axially, the stress is

A)49.9 kg/cm²
B)100 kg/cm²
C)250 kg/cm²
D)175 kg/cm²

Answer 3

49.9 kg/cm²

Question 4

Design of R.C.C. cantilever beams, is based on the resultant force at

A)Fixed end
B)Free end
C)Mid span
D)Mid span and fixed support

Question 5

In a combined footing if shear stress does not exceed 5 kg/cm² , the nominal stirrups provided are

A)6 legged
B)8 legged
C)10 legged
D)12 legged

Question 6

The maximum shear stress (q) in concrete of a reinforced cement concrete beam is

A)Shearforce/(Lever arm×Width)
B)Lever arm/(Shearforce ×Width)
C)Width/(Lever arm × Shearforce)
D)(Shearforce × Width)/Lever arm

Question 7

The thickness of base slab of a retaining wall generally provided, is

A)One half of the width of the stem at thebottom
B)One-third of the width of the stem at the bottom
C)One fourth of the width ofthe steam at the bottom
D)Width of the stem at the bottom

Question 8

If the maximum shear stress at the end of a simply supported R.C.C. beam of 6 m effective span is 10 kg/cm² , the share stirrups are provided for a distance from either end where, is

A)50 cm
B)100 cm
C)150 cm
D)200 cm

Question 9

If T and R are tread and rise respectively of a stair, then

A)2R + T =60
B)R + 2T = 60
C)2R + T = 30
D)R + 2T = 30

Question 10

For stairs spanning l metres longitudinally between supports at the bottom and top of a flight carrying a load w per unit horizontal area, the maximum bending moment per metre width, is

A)wl²/4
B)wl²/8
C)wl²/12
D)wl²/16

Question 11

Though the effective depth of a T-beam is the distance between the top compression edge to the centre of the tensile reinforcement, for heavy loads, it is taken as

A)1/8^th of the span
B)1/10^th of the span
C)1/12^th of the span
D)1/16^th of the span

Question 12

On piles, the drop must be at least

A)80 cm
B)100 cm
C)120 cm
D)140 cm

Question 13

In a pre-stressed beam carrying an external load W with a bent tendon is having angle of inclination ? and pre-stressed load P. The net downward load at the centre is

A) W - 2P cos?
B) W - P cos?
C) W - P sin?
D) W - 2P sin?

Question 14

To have pressure wholly compressive under the base of a retaining wall of width b, the resultant of the weight of the wall and the pressure exerted by the retained, earth should have eccentricity not more than

A)b/3
B)b/4
C)b/5
D)b/6

Question 15

The shear reinforcement in R.C.C. is provided to resist

A)Vertical shear
B)Horizontal shear
C)Diagonal compression
D)Diagonal tension

Question 16

The anchorage value of a hook is assumed sixteen times the diameter of the bar if the angle of the bend, is

A)30°
B)40°
C)45°
D)All the above

Question 17

A circular slab subjected to external loading, deflects to form a

A)Semi-hemisphere
B)Ellipsoid
C)Paraboloid
D)None of these

Question 18

If a rectangular pre-stressed beam of an effective span of 5 meters and carrying a total load 3840 kg/m, is designed by the load balancing method, the central dip of the parabolic tendon should be

A)5 cm
B)10 cm
C)15 cm
D)20 cm

Question 19

The reinforced concrete beam which has width 25 cm, lever arm 40 cm, shear force 6t/cm² , safe shear stress 5 kg/cm² and B.M. 24 mt,

A)Is safe in shear
B)Is unsafe in shear
C)Is over safe in shear
D)Needs redesigning

Question 20

If a bent tendon is required to balance a concentrated load W at the centre of the span L, the central dip h must be at least

A)WL/P
B)WL/2P
C)WL/3P
D)WL/4P

Question 21

If W is total load per unit area on a panel, D is the diameter of the column head, L is the span in two directions, then the sum of the maximum positive bending moment and average of the negative bending moment for the design of the span of a square flat slab, should not be less than

A)WL/12 (L - /3)².
B)WL/10 (L + /3)².
C)WL/10 (L - /3)²
D)WL/12 (L - /3)²

Question 22

A pre-stressed concrete member

A)Is made of concrete
B)Is made of reinforced concrete
C)Is stressed after casting
D)Possesses internal stresses

Question 23

A flat slab is supported

A)On beams
B)On columns
C)On beams and columns
D)On columns monolithically built with slab