Geotechnical Engineering

Shallow Foundations

Question 1
Marks : +2 | -2
Pass Ratio : 100%
The weight of the raft is not considered in the structural design, because ___________
Weight is carried by subsoil
Raft does not remain contact with soil
The weight is transferred to column
All of the mentioned
Explanation:
The weight of the raft is not considered in the structural design because it is assumed to be carried by directly by the subsoil.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
When the allowable soil is low or the building loads are heavy, the footing used is ___________
Raft footing
Strap footing
Trapezoidal combined footing
Rectangular combined footing
Explanation:
When the allowable soil pressure is low, or the building loads are heavy, the use of spread footings would cover more than one-half of the area and it may prove more economical to use mat or raft foundation.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
Which of the following condition is true regarding the transfer of load from strap to soil, used in strap footing?
Transfer load to soil
Does not transfer load to soil
Partially transfer to load
None of the mentioned
Explanation:
The strap used does not remain in contact with soil, and thus does not transfer any pressure to the soil.
Question 4
Marks : +2 | -2
Pass Ratio : 50%
Raft is subdivided in to series of beams to establish __________
Shear failure and Moment diagrams
Pressure distribution
None of the mentioned
All of the mentioned
Explanation:
The raft is subdivided into a series of continuous beams (strips) centered on the appropriate column rows to establish shear failure and moment diagram.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
For a rectangular combined footing, xÌ… is given as ___________
xÌ… = L/2
L/3 < xÌ… < L/2
xÌ… = L/3
None of the mentioned
Explanation:
For a rectangular combined footing, xÌ… = L/2 and for a trapezoidal combined footing solutions lies between the limits L/3 < xÌ… < L/2.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
If the independent spread footing of two columns are connected by a beam, it is called ___________
Combined footing
Trapezoidal combined footing
Strap footing
Raft footing
Explanation:
In strap footing, two independent columns are supported by as trap or beam at the bottom.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
The net ultimate bearing capacity for raft may be determined by __________
Skempton’s equation and Terzaghi’s equation
Darcy’s equation
None of the mentioned
All of the mentioned
Explanation:
The net ultimate bearing capacity may be determined from both Skempton and Terzaghi’s equation as given below:
Question 8
Marks : +2 | -2
Pass Ratio : 100%
The penetration resistance N for designing of raft should be taken at ___________ intervals.
50 cm
60 cm
75 cm
20 cm
Explanation:
The penetration resistance N values should be taken at 75 cm intervals for a depth equal to width of the raft, below the base of the raft.
Question 9
Marks : +2 | -2
Pass Ratio : 50%
The net pressure can be calculated for raft having width greater than ___________
6 m
20 cm
30 cm
4 m
Explanation:
Based on the settlement criterion for raft, the net pressure can be calculated from the following equation having its width greater than 6m.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
The foundation that is used when the soil mass is sufficiently erratic?
Strap footing
Combined footing
Mat footing
Rectangular combined footing
Explanation:
Mat footing is used where the soil contains compressible lenses or the soil is sufficiently erratic so that the differential settlement would be difficult to control.