1. When do strap footings are used in foundation?
a) To transfer load of an isolated column
b) Distance between the columns are long
c) Two column loads are unequal
d) All of the mentioned
Explanation: A strap footing may be used where the distance between the columns is so great that the combined trapezoidal footing becomes quite narrow, with a high bending moment.
2. When two column loads are unequal, which of the possible footing can be provided?
a) Strap footing
b) Raft footing
c) Trapezoidal combined footing
d) Mat footing
Explanation: When the two columns load are unequal, with the outer column carrying a heavier load, and when there is space limitation beyond the outer column, a trapezoidal footing is provided.
3. The total settlement of a footing in clay is considered to be consisting of ___________ components.
a) One
b) Three
c) Two
d) Four
Explanation: According to Skempton and Bjerrum, the total settlement of a footing in clay may be considered to consist of three components
S = Si + Sc + Ss.
4. The component Sc, used in the total settlement of clay refers to which of the following?
a) Total settlement
b) Consolidation settlement
c) Immediate plastic settlement
d) Settlement due to secondary consolidation of clay
Explanation: The three components used in total settlement of clay are given below:
Sc = consolidation settlement
Si = immediate elastic settlement
Ss = settlement due to secondary consolidation of clay.
5. The immediate settlement can be computed from the expression, based on ____________
a) Theory of plasticity
b) Theory of elasticity
c) Terzaghi’s analysis
d) Pressure distribution
Explanation: The immediate settlement is the elastic settlement and can be computed from the following expression based on the theory of elasticity,
Si = q B (1-μ2/E s) I w.
6. The influence factor for rigid square footing is ____________
a) 0.88
b) 0.82
c) 1.06
d) 1.70
Explanation: As suggested by BIS Code IS: 8009 Part 1, 1976 the value of influence factor Iw for rigid footing is 0.82.
7. The equation for computing immediate settlement “Si = μ0μ1 q B ( 1-μ2/Es )” was proposed by ___________
a) Janbu
b) Bjerrum
c) Kjaernsli
d) All of the mentioned
Explanation: In 1966, Janbu, Bjerrum, and Kjaernsli have proposed the following equation for computing the immediate settlement:
Si = μ0μ1 q B (1-μ2/Es).
8. The value of Es used in the immediate settlement equation, can be found out using _____________
a) Triaxial test
b) Compression test
c) Direct shear test
d) Rankine’s theory
Explanation: The modulus of elasticity Es used in the equation Si = μ0μ1 q B (1-μ2/Es) is computed from triaxial test data, where
Es = (σ1-σ3)/ΔL / L.
9. A combined footing may be rectangular in shape if both the columns carry ___________
a) Unequal loads
b) Equal loads
c) No load
d) All of the mentioned
Explanation: The combined footing may be rectangular in shape if both the columns carry equal loads, or may be trapezoidal if they carry unequal loads.
10. The influence factor Iw for rigid rectangular footing with L/B = 1.5 is ____________
a) 0.88
b) 0.82
c) 1.70
d) 1.06
Explanation: Iw = influence factor = 1.06 for rigid rectangular footing, with L/B = 1.5 = 1.70 for rigid rectangular footing, with L/B = 5.