Design of Masonry Structures

The thickness of each leaf of a cavity wall shall not be less than

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7.5 cm
5 cm
15 cm
10 cm

Water retentivity for brick masonry should not be less than

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80 %
60 %
70 %
50 %

For earthquake resistant masonry buildings, the vertical distance between openings one above the other in a load bearing wall shall not be less than

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60 cm
75 cm
50 cm
100 cm

The effective height of free standing non-load bearing wall and column respectively will be

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2.0H and 2.0H
1.5H and 1.5H
2.0H and 1.5H
1.0H and 1.0H

The timber floor not spanning on the masonry wall but properly anchored to the wall gives

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Both lateral and rotational restraints
Lateral restraint but not rotational restraint
Rotational restraint but not lateral restraint
Neither lateral nor rotational restraint

Consider the following statements regarding bands to be provided for strengthening masonry work in masonry buildings constructed in zone III, IV and V.
(i) Lintel band is provided at lintel level on partition walls,
(ii) Gable band is provided at top of gable masonry below the purlins,
(iii) The bands shall be to full width of the wall and not less than 7.5 cm in depth,
(iv) The bands shall be made of reinforced concrete only.
of these statements, the correct statements are

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(i) and (iii)
(i) and (ii)
(ii) and (iii)
(ii) and (iv)

If the horizontal cross-sectional area of a wall is 1200 cm², then the basic stress shall be multiplied by a reduction factor equal to

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0.6
0.75
0.85
0.95

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

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Vi x height of longer opening
Vt x height of longer opening
Vt x height of shorter opening
Ax height of shorter opening

A free standing brick wall 20 cm thick is subjected to a wind pressure of 75 kg/m². The maximum height of wall from stability consideration is

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1.5 m
1.28 m
0.64 m
0.96 m

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

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33? %
25 %
10 %
50 %

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

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20
19
25
15

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

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0.1 MPa
0.15 MPa
0.125 MPa
0.075 MPa

Assertion A : For eccentricity ratio exceeding 1/6, effective thickness of masonry will get reduced.
Reason R : For eccentricity ratio exceeding 1/6, there will be tension on one side of the member.
Select your answer according to the codes give below:

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Both A and R is true and R is the correct explanation of A
A is false but R is true
Both A and R is true and R is not the correct explanation of A
A is true but R is false

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

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1.4
1.2
1.6
2.0

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

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1.0 H
0.75 H
0.85 H
1.5 H

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

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Between 0 and 1
0
1
Greater than 1

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:

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A is false but R is true
Both A and R is true and R is the correct explanation of A
A is true but R is false
Both A and R is true but R is not the correct explanation of A

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 __________ of the total vertical load on the most heavily loaded wall or column in the group

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7 %
4 %
6 %
5 %

Consider the following statements: The use of relatively weak mortar
1. Will accommodate movements due to loads and, cracking if any, and will be distributed as thin hair cracks which are less noticeable or harmful.
2. Will result in reduction of stresses due to differential expansion of masonry units.

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2 alone is correct
1 alone is correct
Both 1 and 2 are correct
Neither 1 nor 2 is correct

For masonry work with solid bricks, consistency of mortar should be

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19 to 23 cm
5 to 8 cm
14 to 18 cm
9 to 13 cm

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

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(ii) and (iii) are correct
Only (ii) is correct
(i) and (ii) are correct
(i), (ii) and (iii) are correct

Assertion A : Lime based mortars give higher ratio of brickwork strength to mortar strength as compared to non-lime mortar.
Reason R : Lime based mortars have lower bond strength as compared to non-lime mortars.
Select your answer according to the codes given below:

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Both A and R is true and R is the correct explanation of A
Both A and R is true but R is not the correct explanation of A
A is true but R is false
A is false but R is true

Minimum compressive strength in N/mm² for H1 type mortar used for masonry is

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3
10
5
7.5

Consider the following statements:
1. Masonry in rich cement 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?

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2 and 3
1 and 2
1, 2 and 3
1 and 3

Minimum thickness of stiffening wall for 1 to 3 storeys shall not be less than

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15 cm
10 cm
30 cm
20 cm

A 200 mm thick brick masonry wall made of modular bricks carries an axial load of 30 kN/m from wall above and an eccentric load of 20 kN/m from RCC floor acting at a distance of 47.5 mm from the centre line of the wall. The resultant eccentricity ratio is

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0.095
0.100
0.105
0.090

Direct load carrying capacity of a brick masonry wall standing freely as against when it supports RC slab will be

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Less
The same in both the cases
More
100 %

Consider the following statements regarding provision of chases in masonry,
(i) No chase should be permitted in a half brick load-bearing 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.

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

Assertion A : For identical strength, a composite cement-lime mortar is preferred over cement mortar.
Reason R : Composite cement-lime mortar has higher drying shrinkage than cement mortar.
Select your answer based on the codes given below. Codes:

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A is false but R is true
A is true but R is false
Both A and R is true but R is not a correct explanation of A
Both A and R is true and R is the correct explanation of A

Assertion A : Limiting value of slenderness ratio for a column is less than that of a wall.
Reason R : A column can buckle around either of the two horizontal axes while a wall can buckle around only one axis.
Select your answer according to the codes given below:

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Both A and R is true but R is not the correct explanation of A
A is true but R is false
A is false but R is true
Both A and R is true and R is the correct explanation of A

For designing masonry components of a structure, seismic forces provision in the design calculation is not necessary for buildings constructed in

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Zone I and II
Zone I, II and III
Zone I only
Zone I, II, III and IV

For strengthening a 50 m long and 5 m high straight compound wall built in brick work, which one of the following would be most suitable?

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Using stronger bricks
Providing a deeper foundation
Providing buttresses at certain intervals
Using a richer mortar

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

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Buckling
Any of the above
Shear
Vertical tensile splitting

Maximum slenderness ratio of load bearing walls for a dwelling having more than 2 storeys
(i) Shall not exceed 12 if lime mortar is used
(ii) Shall not exceed 18 if cement lime mortar 1 : 2 : 9 is used
(iii) Shall not exceed 24 if cement mortar 1 : 6 is used

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

Rich cement mortars are more liable to cracking as compared to lean mortars because rich mortars have

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None of above
Both (A) and (B)
High shrinkage
Less strength

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

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1.0 kg/cm²
0.4 kg/cm²
1.2 kg/cm²
0.7 kg/cm²

Consider the following statements:
A high lime content in a composite cement-lime mortar results in
1. Slow hardening.
2. Quick setting.
3. Weaker mortar.

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1 and 3 are correct
2 and 3 are correct
1 and 2 are correct
1, 2 and 3 are correct

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

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Actual thickness of the stronger leaf
Sum of thickness of both leaves
Two-third of the sum of thickness of both the leaves
Larger of (B) and (C)

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

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

The bending stress in a wall or column subjected to effective vertical load need not be considered, if the eccentricity ratio is

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More than 1/24
Less than or equal to 1/12
Less than or equal to 1/24
Less than or equal to 1/6

Design of Masonry Structures : Question 1 of 40