This set of Geotechnical Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Machine Foundations – Barkens Method”.
1. The equation for natural frequency of system as suggested by Barken is __________
a) ωn = √f(1 – r2)
b) ωn = √cu A / m
c) ωn = cu A / m
d) None of the mentioned
View Answer
Explanation: Barken suggested the following equation for the natural frequency of the system
ωn = √cu A / m
Where cu = co-efficient of elastic uniform compression of soil
A = contact area of foundation with soil
m = mass of machine plus foundation.
2. The co-efficient of elastic uniform compression of soil depends on which of the following factor?
a) Size of area of foundation
b) Mass of foundation
c) Exciting force
d) All of the mentioned
View Answer
Explanation: The coefficient of elastic uniform compression of soil depends not only on elastic constant E and μ but also on the size of the base contact area of foundation.
3. On calculating the natural frequency of the system, Barken did not take into account of __________
a) Contact area
b) Frequency ratio
c) Mass of the vibrating soil
d) Mass of machine
View Answer
Explanation: The formula suggested by Barken for natural frequency does not take into account of the mass of soil vibrating with the foundations.
4. What are the methods for determining the natural frequency of the foundation of soil system?
a) Barken’s method and Rankine’s method
b) Pauw’s method
c) None of the mentioned
d) All of the mentioned
View Answer
Explanation: The three methods of determining the natural frequency of the foundation soil system are: i) Barken’s method ii) Balakrishna Rao’s method iii) Pauw’s method.
5. In a damped force vibratory system, the support is derived by _______
a) Co-vibrating body
b) Spring mass system
c) Transmitting force
d) Soil mass
View Answer
Explanation: In a damped force vibratory system, the support is derived from the foundation by way of transmitting a force (FT) to the foundation.
6. The size of co-vibrating body of soil depends on _________
a) Soil mass
b) Apparent soil mass
c) Transmitted force
d) Size of the base area
View Answer
Explanation: The size of co-vibrating body of soil depends on frequency and is influenced by the size of the base area of the vibrator and by the elastic properties of the soil.
7. The mass of co-vibrating soil is called __________
a) Weight of vibrator
b) Soil mass
c) Apparent soil mass
d) Certain soil mass
View Answer
Explanation: The mass of co-vibrating soil is called the apparent soil mass ms, participating in the vibrations.
8. Recommended design value for permissible load on soil under the action of static load, for rock type soil group is ________
a) Greater than 10
b) 5-10
c) 3.5-5
d) Greater than 5
View Answer
Explanation: The recommended design value of the co-efficient of elastic uniform compression for permissible load on soil under action of static load only is greater than 5 kg/cm2.
9. The bulb of pressure concept for calculating the apparent mass of soil was introduced by _________
a) Balakrishna and Nag raj
b) Barken
c) None of the mentioned
d) All of the mentioned
View Answer
Explanation: In 1960, Balakrishna and Nag raj proposed the bulb of pressure concept of calculating the apparent mass of soil participating in the vibration.
10. An aim of the foundation designer should be such that the frequency ratio f/fn is either less than _________
a) 1.5
b) 0.6
c) 2.0
d) 3.4
View Answer
Explanation: The aim of the designer should be such that the frequency ratio f/fn is either less than 0.6 or more than 1.5 by suitably proportioning it.
Sanfoundry Global Education & Learning Series – Geotechnical Engineering.
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