Design of Concrete Structures 7

Objective Questions and Answers of Civil Engineering: Design of Concrete Structures 7

Subject: Design of Concrete Structures 7

Part 7: Objective questions and answers of Design of Concrete Structures

 

Q1. In symmetrically reinforced sections, shrinkage stresses in concrete and steel are respectively

a) Compressive and tensile

b) Tensile and compressive

c) Both compressive

d) Both tensile

 

Q2. The maximum value of hoop compression in a dome is given by

a) Wr / 4d

b) Wr/2d

c) Wr/d

d) 2wr/d

Where, w = load per unit area of surface of dome r = radius of curvature

D = thickness of dome

 

Q3. The purpose of reinforcement in prestressed concrete is

a) To provide adequate bond stress

b) To resist tensile stresses

c) To impart initial compressive stress in concrete

d) All of the above

 

Q4. Most common method of prestressing used for factory production is

a) Long line method

b) Freyssinet system

c) Magnel-blaton system

d) Lee-macall system

 

Q5. Which of the following losses of prestress occurs only in pretensioning and not in  posttensioning?

a) Elastic shortening of concrete

b) Shrinkage of concrete

c) Creep of concrete

d) Loss due to friction

 

Q6. Which of the following has high tensile strength?

a) Plain hot rolled wires

b) Cold drawn wires

c) Heat treated rolled wires

d) All have same tensile strength

 

Q7. Stress strain curve of high tensile steel

a) Has a definite yield point

b) Does not show definite yield point but yield point is defined by 0.1% proof stress

c) Does not show definite yield point but yield point is defined by 0.2% proof stress

d) Does not show definite yield point but yield point is defined by 2% proof stress,

 

Q8. Cube strength of controlled concrete to be used for pretensioned and post-tensioned work respectively should not be less than

a) 35 mpa and 42 mpa

b) 42 mpa and 35 mpa

c) 42 mpa and 53 mpa

d) 53 mpa and 42 mpa

 

Q9. In a spherical dome subjected to concentrated load at crown or uniformly distributed load, the meridional force is always

a) Zero

b) Tensile

c) Compressive

d) Tensile or compressive

 

Q10. In a ring beam subjected to uniformly distributed load

I) shear force at mid span is zero

Ii) shear force at mid span is maximum

Iii) torsion at mid span is zero

Iv) torsion at mid span is maximum the correct answer is

a) (i) and (iii)

b) (i)and(iv)

c) (ii) and (iii)

d) (ii) and (iv)

 

Q11. In prestressed concrete

a) Forces of tension and compression change but lever arm remains unchanged

b) Forces of tension and compressions remain unchanged but lever arm changes with the moment

c) Both forces of tension and compression as well as lever arm change

d) Both forces of tension and compression as well as lever arm remain unchanged

 

Q12. Normally prestressing wires are arranged in the

a) Upper part of the beam

b) Lower part of the beam

c) Center

d) Anywhere

 

Q13. Select the incorrect statement

a) The loss of prestress is more in pre-tensioning system than in posttensioning system.

b) Pretensioning system has greater certainty about its durability.

c) For heavy loads and large spans in buildings or bridges, posttensioning system is cheaper than pretensioning system

d) None of the above

 

Q14. Prestress loss due to friction occurs

a) Only in post-tensioned beams

b) Only in pretensioned beams

c) In both post-tensioned and preten-sioned beams

d) None of the above

 

Q15. High carbon content in the steel causes

a) Decrease in tensile strength but increase in ductility

b) Increase in tensile strength but decrease in ductility

c) Decrease in both tensile strength and ductility

d) Increase in both tensile strength and ductility

 

Q16. Select the correct statement

a) Elastic modulus of high tensile steel is nearly the same as that of mild steel.

b) Elastic modulus of high tensile steel is more than that of mild steel.

c) Carbon percentage in high carbon steel is less than that in mild steel.

d) High tensile steel is cheaper than mild steel.

 

Q17. Ultimate strength of cold drawn high steel wires

a) Increases with increase in diameter of bar

b) Decreases with increase in diameter of bar

c) Does not depend on diameter of bar

d) None of the above

 

Q18. If the ratio of center to center spacing of intersecting walls to actual thickness of intersecting wall is more than 20, then the stiffening coefficient for wall proper will be

a) 0

b) between 0 and 1

c) 1

d) greater than 1

 

Q19. Where a structural component or a system is providing lateral support to five or more walls or columns, the lateral load to be resisted may be taken as

a) 4 percent

b) 5 percent

c) 6 percent

d) 7 percent of the total vertical load on the most heavily loaded wall or column in the group.

 

Q20. If H is the height of wall between centers of supports, then the effective height of wall where concrete floors have a bearing on wall irrespective of the direction of span will be

a) 0.75 H

b) 0.85 H

c) 1.0 H

d) 1.5 H

 

Part 7: Objective questions and answers of Design of Concrete Structures

 

Q1. Answer b

 

Q2. Answer b

 

Q3. Answer c

 

Q4. Answer a

 

Q5. Answer a

 

Q6. Answer b

 

Q7. Answer c

 

Q8. Answer b

 

Q9. Answer c

 

Q10. Answer a

 

Q11. Answer b

 

Q12. Answer b

 

Q13. Answer d

 

Q14. Answer a

 

Q15. Answer b

 

Q16. Answer a

 

Q17. Answer b

 

Q18. Answer d

 

Q19. Answer d

 

Q20. Answer a