250+ TOP MCQs on Effective Length and Thickness of Wall and Answers

Building Construction Multiple Choice Questions & Answers (MCQs) on “Effective Length and Thickness of Wall”.

1. L is the length measured between _________ of piers.
a) Ends
b) Centers
c) Edges
d) Faces
Answer: b
Clarification: Actual length of a wall is denoted by L whereas effective length is denoted by l. Actual length (L) is the length which is measured between the centers of piers.

2. Effective length of a wall supported by a buttress at each end is ________
a) 0.8L
b) 1.0L
c) 1.5L
d) 2.0L
Answer: b
Clarification: Effective length of a wall supported by a buttress at each end is 1.0L where L is the actual length of the wall. Effective length of a wall varies with the variations in the conditions of support.

3. Effective thickness is equal to the actual thickness for solid walls.
a) True
b) False
Answer: a
Clarification: In the case of solid or faced walls, effective thickness is equal to the actual thickness. But if the solid walls are bonded into piers and it is given that the slenderness ratio is based on the effective height, then effective thickness is calculated by multiplying actual thickness with a constant called stiffening coefficient.

4. Effective length of a wall when it is supported by a buttress only at one end is __________
a) 1.5L
b) 1.0L
c) 0.5L
d) 2.0L
Answer: a
Clarification: Effective length of a wall when it is supported by a buttress only at one end is 1.5L where L is the actual length of the wall. In this case, the wall is free at the other end. The support can be provided by a cross-wall also instead of a buttress.

5. Effective thickness of masonry is reduced if the eccentricity ratio exceeds ___________
a) 1/2
b) 1/3
c) 1/5
d) 1/6
Answer: d
Clarification: Effective thickness of masonry is reduced if the eccentricity ratio exceeds 1/6. When the eccentricity ratio exceeds 1/6, it results in the tension on one side of the member which reduces the effective thickness.

6. The effective thickness should be _________ of the sum of actual thicknesses of the two skins of a cavity wall if both the skins have uniform thickness throughout.
a) One-fourth
b) Half
c) Two-thirds
d) One-third
Answer: c
Clarification: The effective thickness should be two-thirds of the sum of the actual thicknesses of the two skins of a cavity wall. This is applicable only if both the skins or leaves of the cavity wall are of uniform thickness throughout.

7. The stiffening coefficient varies inversely with the __________
a) Actual thickness of the wall
b) Thickness of pier
c) Spacing of wall
d) Width of pier
Answer: a
Clarification: The stiffening coefficient depends on the thickness of the pier to which the wall is bonded and the actual thickness of the wall. It varies directly with the thickness of the pier and inversely with the actual thickness of the wall.

8. The effective thickness of a __________ column is equal to the actual thickness.
a) Square
b) Rectangular
c) Circular
d) Trapezoidal
Answer: b
Clarification: The effective thickness of a rectangular column is equal to the actual thickness. The effective thickness for non-rectangular columns is calculated by multiplying the thickness of the square column with the moment of inertia.

9. Effective length of a continuous wall supported by piers is ___________
a) 0.8L
b) 1.0L
c) 1.5L
d) 2.0L
Answer: a
Clarification: Effective length of a continuous wall supported by piers is 0.8L. The support can be provided by buttresses or cross-walls as well. However, when a wall is supported at both its ends, then the effective length becomes 1.0L.

10. Effective length of a continuous wall is 0.8L when there is no opening within _________ of the height of the wall.
a) One-fourth
b) One-eighth
c) One-sixteenth
d) One-half
Answer: b
Clarification: Effective length of a continuous wall is 0.8L when there is no opening within one-eighth of the height of the wall. Therefore, when the opening in the wall is not closer than H/8 from the cross wall, then the effective length is 0.8, where H represents the actual height of the wall.