This set of Repair and Rehabilitation of Structures Multiple Choice Questions & Answers (MCQs) focuses on “Building Cracks”.
1. The cracks that occur due to incorrect design or faulty construction is called _________
a) structural cracks
b) non-structural cracks
c) pattern cracks
d) hair line cracks
View Answer
Explanation: A structural crack indicates that the design of the structural element is not in order and the construction practice adopted is also not correct which results in extensive cracking of the structural elements. Other types of cracks mentioned above don’t have any structural and design aspects behind their occurrence.
2. Non-structural cracks occurs due to ____________
a) faulty construction
b) internally induced stress in the building
c) incorrect design
d) overloading
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Explanation: A non-structural crack occurs due to internally induced stress in the building leading to the feeling of instability in the building. The remaining above-mentioned causes are the causes of structural cracks.
3. The occurrence of closely spaced fine cracks at the surface of a material is called as ______
a) crazing
b) pattern cracking
c) scaling
d) peeling
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Explanation: The occurrence of closely spaced fine cracks at the surface of a material is called as crazing that occurs under tensile stress and the plane of crazing corresponds to the stress direction.
4. What is the width of fine cracks?
a) Less than 0.08 inches wide
b) Between 0.04 to 0.08 inches wide
c) Less than 0.04 inches wide
d) Greater than 1mm wide
View Answer
Explanation: A fine crack is less than 0.04 inches wide and occurs generally due to foundation settlement or sulphate action in foundation concrete and masonry in foundation and plinth.
5. The cracks that tend to be short and uniformly distributed throughout the concrete surface is called as ________
a) medium cracks
b) non-structural cracks
c) thin cracks
d) pattern cracks
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Explanation: A pattern cracks indicates the restraint of contraction on the surface layer by backing or inner concrete or it can be also due to an increase in the volume of the interior concrete.
6. Which type of cracks indicates the development of tension in concrete?
a) D-cracking
b) Crazing
c) Medium cracks
d) Isolation crack
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Explanation: Isolation crack indicates the tension on concrete and the tension development is usually perpendicular to the cracks. Sometimes these cracks can also run in a diagonal, longitudinal, transverse, and vertical or in horizontal direction.
7. What is the width of medium cracks?
a) Less than 0.08 inches wide
b) Between 0.04 to 0.08 inches wide
c) Less than 0.04 inches wide
d) Greater than 1mm wide
View Answer
Explanation: A fine crack is between 0.04 to 0.08 inches wide and occurs generally due to foundation settlement or sulphate action in foundation concrete and masonry in foundation and plinth.
8. Which type of crack is more serious for the building?
a) Dormant cracks
b) Individual cracks
c) Active cracks
d) Hairline cracks
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Explanation: Active cracks are more serious for the building because they continue to increase in their width tremendously leading to an increase in the magnitude of the movement of cracks, which leads to the instability of the structure.
9. Which of the following cracks are easily identified by the line demonstrated in the laboratory load test?
a) Dormant cracks
b) Solitary cracks
c) Overload cracks
d) Pattern cracks
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Explanation: Overload cracks are easily identified by the line demonstrated in laboratory load test and they mainly occur due to the overload that comes to the structural elements. The over loading may be due to any sudden loads due to any structural damage to the element.
10. Irregular distribution of solitary cracks indicates __________
a) faults in construction
b) poor construction practice and poor design
c) overloading of structural elements
d) overstressing of concrete
View Answer
Explanation: Irregular distribution of solitary cracks indicates poor construction practice and poor design and it mainly occurs in a long retaining wall or long channels. They occur due to the positive overstressing of concrete due to load or shrinkage.
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.
