This set of Repair and Rehabilitation of Structures Multiple Choice Questions & Answers (MCQs) focuses on “Common Crack Patterns in Buildings – Set 2”.
1. Horizontal cracks at the lintel or sill level in top storey occurs when the window and room spans are _____________
a) small
b) large
c) equal
d) wider
View Answer
Explanation: When the room and window spans are large the horizontal cracks occurs at the lintel or sill level in top storey of the building due to the pull exerted by the wall on the adjacent slab due to drying shrinkage and movements caused because of the thermal movement. And these cracks could be prevented by providing slip joints at the supporting walls.
2. ___________ cracks are found over the lintels spanning over the large opening.
a) Horizontal
b) Vertical
c) Diagonal
d) Shear
View Answer
Explanation: Usually diagonal cracks are that occur due to the drying shrinkage of the in-situ RCC lintel and are mainly observed during the first dry spell after the construction and they can be prevented by using low shrinkage or low slump or even by pre-cast lintels.
3. The external walls that do not take any load and act as non-load bearing walls in a framed structure are termed as _____________ walls.
a) main
b) shear
c) vertical
d) auitcase
View Answer
Explanation: In the framed structure, the walls that don’t take any loads are termed as panel walls which are just built to act as a partition to the number of rooms that are built in a building.
4. Horizontal flexure cracks occur when the walls are subjected to a large compressive force.
a) True
b) False
View Answer
Explanation: When the columns undergo shortening which is caused by elastic deformation, creep or drying shrinkage or sometimes even due to greater deflection of upper beam when acted upon by heavy loads eventually the walls now get subjected to large compressive loads that result in bulking of column leading to the formation of horizontal flexure cracks.
5. Damage due to the formation of horizontal flexure cracks increases when the time interval between casting of the frame and the building up of masonry wall is less.
a) True
b) False
View Answer
Explanation: The horizontal flexure cracks become apparent after few years and are accompanied by bowing of the wails. When the time interval between casting of the frame and building up of masonry wall is less, the water during casting remains stagnant and leads to the formation of horizontal flexure cracks.
6. In case of the long panels that are built tightly between the RCC columns, the vertical cracks develop.
a) True
b) False
View Answer
Explanation: When long panels are built tightly between RCC columns then the brick work may undergo compression due to thermal and moisture penetration and they undergo buckling there by developing vertical cracks.
7. The remedial solution to the vertical cracks is done by providing ______ joint.
a) slip
b) horizontal
c) expansion
d) movement
View Answer
Explanation: The best remedial solution to the formation of vertical cracks is provided by decreasing the force in the panel by opening out the horizontal joint in between the wall top and beam bottom and the joint is filled with joint filling compound.
8. When no opening is provided in the panel walls then the horizontal cracks occur in masonry at the edge.
a) True
b) False
View Answer
Explanation: When deflection occurs in the floor, middle portion of the wall start to lose its support and when the length to height ratio is larger, then the load of the panel walls gets transferred to the end of the support by beam action and so horizontal cracks occur at the supports.
9. When there is a central opening in the panel walls and length to height of panel wall is large _________ cracks occur.
a) Shear
b) Diagonal
c) Horizontal
d) Vertical
View Answer
Explanation: Due to the combined action of flexural tension in the masonry portion above the opening and also due to the self weight of the unsupported masonry on the side of the opening diagonal cracks starts to occur from the lintels where they are wider in width and thinner in width as they travel upward.
10. When there is a central opening in the panel walls and length to height of panel wall is small _________ cracks occur.
a) Shear
b) Diagonal
c) Horizontal
d) Vertical
View Answer
Explanation: Horizontal cracks occurs when there is a central opening in the panel walls and length to the height of panel wall is small and the reason for this is mainly due to the tension and also due to the self weight of the masonry on the sides of the opening.
Sanfoundry Global Education & Learning Series – Repair and Rehabilitation of Structures.
To practice all areas of Repair and Rehabilitation of Structures, here is complete set of Multiple Choice Questions and Answers.
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