Engineering Questions with Answers - Multiple Choice Questions
Minimum Depth of Foundation: Rankine’s Analysis
1 - Question
The gross pressure intensity (q) of a structure is ___________
a) Total pressure at base of the footing
b) Excess pressure after the construction of the structure
c) Minimum pressure intensity at the base
d) None of the mentioned
View Answer
Answer: a
Explanation: The gross pressure intensity q is the total pressure at the base of the footing due to the weight of the superstructure.
2 - Question
The ultimate bearing capacity and the net ultimate capacity are connected by the relation ____________
a) qf = qnf +/- σ̅ and qf = qf – σ̅
b) qf = qnf – σ̅
c) None of the mentioned
d) All of the mentioned
View Answer
Answer: a
Explanation: The ultimate bearing capacity qf and the net ultimate capacity are connected by the following relation:
qf = qnf + σ̅ (or) qf = qf – σ̅
where σ̅ is the effective surcharge at the base level of the foundation.
3 - Question
The net safe bearing capacity is defined by which of the following equation?
a) qns=qnf / F
b) qns = qnf + σ̅
c) qns = qf – σ̅
d) All of the mentioned
View Answer
Answer: a
Explanation: The net safe bearing capacity is the net ultimate bearing capacity divided by a factor of safety F i.e., qns = qnf/F.
4 - Question
The safe bearing capacity can also be referred as _________
a) Net safe bearing capacity
b) Ultimate bearing capacity
c) Safe bearing pressure
d) Net soil pressure
View Answer
Answer: b
Explanation: Sometimes, the safe bearing capacity is also referred to as the ultimate bearing capacity qf divided by a factor of safety F.
5 - Question
Rankine considered the first soil element (element 1) at ___________
a) Base of the structure
b) Below the foundation
c) Edge of the footing
d) All of the mentioned
View Answer
Answer: b
Explanation: Rankine considered the equilibrium of two soil elements, The first one immediately below the foundation (element 1).
6 - Question
The bearing capacity of cohesion-less soil at the ground surface is __________
a) Unity
b) Less than one
c) Zero
d) Greater than one
View Answer
Answer: c
Explanation: According to Rankine’s equation bearing capacity of cohesion less soil is zero at the ground surface.
7 - Question
When a state of equilibrium is reached under the footing?
a) Load on footing increase
b) Load on footing decreases
c) Safe bearing capacity of the soil is reached
d) None of the mentioned
View Answer
Answer: a
Explanation: When the load on footing increases, and approaches a value qf, a state of plastic equilibrium is reached under the footing.
8 - Question
Rankine considered the equilibrium of second soil element at __________
a) Base of the structure
b) Below the foundation
c) Edge of the footing
d) Top of the foundation
View Answer
Answer: c
Explanation: Rankine considered the equilibrium of the other soil element (element 2) beyond the edge of the footing, but adjacent to element 1.
9 - Question
During the state of shear failure, which of the following principal stress relationship exist?
a) σ1 = σ tan α + 2c tan α
b) σ1 = σ3 tan2 α + 2c tan α
c) σ1 = 2c tan α
d) σ1 = σ3 tan α
View Answer
Answer: b
Explanation: During the state of shear failure (plastic equilibrium), the following principal stress relationship exists σ1 = σ3 tan2 α + 2c tan α
for cohesion-less soil,σ1 = σ3 tan2 α.
10 - Question
The symbol σ̅, represent which of the following term?
a) Ultimate bearing capacity
b) Effective surcharge
c) Gross pressure intensity
d) Bearing capacity
View Answer
Answer: b
Explanation: σ̅ represents the effective surcharge at the base level of the foundation, assuming total unit weight for the portion of the soil above the water table and submerged unit weight for the portion below the water table.