Engineering Questions with Answers - Multiple Choice Questions
Dynamic Analysis of Block Foundations
1 - Question
The method of Barken is based on the assumption of ___________
a) Equation of motion
b) Linear spring theory
c) Participation of soil in the vibration
d) All of the mentioned
View Answer
Answer: b
Explanation: Barken’s method is based on linear spring theory. The method neglects the effect of damping and participating in the soil mass.
2 - Question
The rotation of foundation about y axes is known as _____________
a) Yawning
b) Pitching
c) Rocking
d) All of the mentioned
View Answer
Answer: c
Explanation: In the general case, rotation about y, z and x-axes are respectively known as rocking, yawning and pitching.
3 - Question
Barken’s method is used in ___________ places.
a) Congested area
b) Design offices
c) Working area
d) All of the mentioned
View Answer
Answer: c
Explanation: Barken’s method is very much used in design offices.
4 - Question
If the combined C.G. of the machine and foundation lies in the same vertical line, then the twisting modes are _________
a) Coupled
b) Uncoupled
c) All of the mentioned
d) None of the mentioned
View Answer
Answer: b
Explanation: If the combined C.G. of the machine and foundation lies in the same vertical line as the centroid of the base plane, then the vertical and translation and twisting modes are uncoupled.
5 - Question
The value of kx for the elastic support of soil is given by which of the following expression?
a) Kx = Cu A
b) Kx = Cϴ Iy
c) Kx = Cx A
d) Kx = Cu Iy
View Answer
Answer: c
Explanation: The values of Kx, Ky and Kϴy for the elastic support of soil are given by the following expressions:
For vertical motion: Kz = Cu A
For horizontal motion: Kx = Cx A
For rocking motion: Kϴy: Cϴ Iy.
6 - Question
The permissible amplitude should not exceed ___________ for reciprocating machine.
a) Probable amplitude
b) Limiting amplitude
c) Maximum amplitude
d) Minimum amplitude
View Answer
Answer: b
Explanation: The permissible amplitude should not exceed the limiting amplitude for the machine prescribed by the manufacturers.
7 - Question
The methods of Pauw and Balakrishna Rao are based on ___________ assumptions.
a) Equation of motion
b) Linear spring theory
c) Participation of soil in the vibration
d) Barken’s method
View Answer
Answer: c
Explanation: The method of Pauw and Balakrishna Rao are based on the assumption that a certain mass of soil participates in the vibration with the foundation.
8 - Question
According to Barken, the value of the coefficient of elastic uniform shear is taken as __________
a) 0.5
b) 2 Cu
c) 3.0
d) 0.5 Cu
View Answer
Answer: d
Explanation: According to Barken, the coefficient of elastic uniform shear Cτ for foundation resting on elastic support is taken as 0.5 Cu.
9 - Question
If foundation block is supported by an elastic pad of contact area A and thickness t, the value of stiffness factor for vertical motion is given by which of the following expression?
a) Kx = C A/t
b) Kz = E A/t
c) Kϴy = Ely / t
d) All of the mentioned
View Answer
Answer: b
Explanation: The value of stiffness factors are given by the following expressions:
For vertical motion: Kz = E A /t
For horizontal (sliding motion): Kx = CA /t
For rocking motion: Kϴy = Ely/t.
10 - Question
The two natural frequencies representing the couple motion, in sliding and rocking motion is ___________
a) ωn1 and ωn2
b) ωx and ωy
c) ωϴ and ωn
d) ωn1 and ωn
View Answer
Answer: a
Explanation: ωn1 and ωn2 are the two natural frequencies representing the coupled action (i.e., sliding along x-axis and rocking about the y-axis).