# Design of Concrete Structures 9

Objective Questions and Answers of Civil Engineering: Design of Concrete Structures 9

Subject: Design of Concrete Structures 9

Part 9: Objective questions and answers of Design of Concrete Structures

Q1. If the eccentricity ratio is more than 1/24, then increase in the permissible stress in the design of wall subjected to eccentric loading as per code is

a) 10%

b) 25%

c) 33 1/3%

d) 50%

Q2. The mode of failure of a very short masonry member having h/t ratio of less than 4 is by

a) shear

b) vertical tensile splitting

c) buckling

d) any of the above

Q3. Assertion A : From consideration of structural soundness and economy of design, most codes control the maximum slenderness ratio of masonry walls and columns.

Reason R : By controlling the maximum slenderness ratio, failure is by excessive stress and not by buckling. Select your answer according to codes given below:

a) Both A and R are true and R is the correct explanation of A.

b) Both A and R are true but R is not .the correct explanation of A.

c) A is true but R is false.

d) A is false but R is true.

Q4. Full restraint is provided by

(i) foundation footing of a wall

(ii) timber floor spanning on the wall and anchored to the wall

(iii) RCC slab with a minimum bearing of 10 cm on the wall

Of these statements

a) (i) and (iii) are correct

b) (i) and (ii) are correct

c) (ii) and (iii) are correct

d) (i), (ii) and (iii) are correct

Q5. Assertion A : Lime based mortars give higher ratio of brickwork strength to mortar strength as compared to nonlime mortar.

Reason R : Lime based mortars have lower bond strength as compared to non-lime mortars.

a) Both A and R are true and R is the correct explanation of A.

b) Both A and R are true but R is not the correct explanation of A.

c) A is true but R is false.

d) A is false but R is true.

Q6. Water retentivity for brick masonry should not be less than

a) 50%

b) 60%

c) 70%

d) 80%

Q7. Minimum compressive strength in N/mm^2 for H1 type mortar used for masonry is

a) 3

b) 5

c) 7.5

d) 10

Q8. Cement mortars richer than 1: 3 are not used in masonry because

(i) There is no gain in strength of masonry

(ii) There is high shrinkage

(iii) They are prone to

Segregation Of these statements

a) Only (ii) is correct

b) (i) and (ii) are correct

c) (ii) and (iii) are correct

d) (i), (ii) and (iii) are correct

Q9. For earthquake resistant masonry buildings, where seismic coefficient is less than 0.08, the horizontal distance between two openings shall not be less than

a) Vt x height of shorter opening

b) Vt x height of longer opening

c) Ax height of shorter opening

d) Vi x height of longer opening

Q10. In a cavity wall, both leaves of which are load bearing, the effective thickness is taken as

a) sum of thickness of both leaves

b) two-third of the sum of thickness of both the leaves

c) actual thickness of the stronger leaf

d) larger of (b) and (c)

Q11. Consider the following statements regarding provision of chases in masonry,

(i) No chase should be permitted in a half brick loadbearing wall,

(ii) Vertical chases should not be closer than 2 m in any stretch of a wall,

(iii) Chases should be provided near to bearings of beams and lintels.

Of these statements

a) (i) and (ii) are correct

b) (i) and (iii) are correct

c) (ii) and (iii) are correct

d) (i), (ii) and (iii) are correct

Q12. In the case of panel wall subjected to horizontal loads at right angles to the plane of the wall, with the mortar not leaner than Ml type, tensile stress in bending in the vertical

direction may be allowed to the extent of

a) 0.4 kg/cm^2

b) 0.7 kg/cm^2

c) 1.0 kg/cm^2

d) 1.2 kg/cm^2

Q13. Consider the following statements: Sand in mortar is needed for

1. Decreasing the quantity of cement.

2. Reducing shrinkage.

3. Decreasing the surface area of the binding material.

4. Increasing the strength.

Of these statements:

a) 2, 3 and 4 are correct

b) 1,2 and 3 are correct

c) 1,3 and 4 are correct

d) 1,2 and 4 are correct

Q14. The mortars used for masonry construction are classified based on strength in IS 2250 and IS 1905 according to their designations L1,L2, H1, H2, M, M2.

The correct sequence of increasing order of their strengths is

a) LLLZ.HLHI.MLMJ

b) L2,L,,M2>Mi,H2)H,

c) M,,M2, H,,H2,Li,L2

d) L2,L,,M,,M2,H,,H2

Q15. A 200 mm thick wall made of modular bricks is 5 m long between cross walls and 3.8 m clear height between RCC slabs at top and bottom. The slenderness ratio of the wall is

a) 15

b) 19

c) 20

d) 25

Q16.The basic stress in masonry units having height to width ratio of 1.5 may be increased by a factor of

a) 1.2

b) 1.4

c) 1.6

d) 2.0

Q17. Consider the following statements:

1. Masonry in rich cements mortar though having good strength with high shrinkage is much

liable for surface cracks.

2. Lime mortar possesses poor workability and poor water retentivity and also suffers high shrinkage.

3. Masonry in lime mortar has better resistance against rain penetration and is less liable to crack when compared to masonry in cement mortar.

Which of these statements are correct?

a) 1,2 and 3

b) 1 and 2

c) 2 and 3

d) 1 and 3

Q18. For masonry built in 1:1:6 cement-lime-sand mix mortar or equivalent, the horizontal shear stress permissible on the area of a mortar bed joint is

a) 0.15 MPa

b) 0.125 MPa

c) 0.1 MPa

d) 0.075 MPa

Q19. If two forces are in equilibrium, then the forces must

I) be equal in magnitude

Ii) be opposite in sense

Iii) act along the same line

a) (i) and (ii)

b) (i) and (iii)

c) Only (i)

d) (i), (ii) and (iii)

Q20. The function of cleats in a roof truss is

a) To support the common rafter

b) To support purlins

c) To prevent the purlins from tilting

d) All of the above

Part 9: Objective questions and answers of Design of Concrete Structures