Jawaharlal Nehru Technological University Hyderabad 2007 B.E Civil Engineering SOIL DYNAMICS AND MACHINE FOUNDATION (set no1) - Question Paper

1. (a) Classify machine foundations according to I.S.Code with neat sketches [8]
(b) explain the values of permissible amplitudes suggested by B.I.S for the foun-
dations of various kinds of machines. [8]
2. (a) Write a critical note on Logarithmic decrement [6]
(b) The exciting force in a constant force amplitude excitation is 120kN. The
natural frequency of the machine foundation is 4Hz. The damping factor is
0.36. Determine the magnification factor and the transmitted force at an
operating frequency of 10 Hz. [10]
3. (a) explain Tschebotarioff?s decreased natural frequency. [8]
(b) define the factors affecting co-efficient of elastic uniform compression. [8]
4. (a) elaborate the various methods of vibration isolation [8]
(b) explain properties of vibration isolating materials. [8]
5. elaborate the laboratory methods used to determine the dynamic properties of
soils? discuss them in brief. [16]
6. (a) What is apparent soil mass? discuss how Pauw used this concept to arrive
at the natural frequency of a machine foundation soil system? [10]
(b) What is a bulb of pressure concept? [6]
7. (a) elaborate the changes made by Quinlan and Sung to Reissner?s theory?
Explain. [10]
(b) discuss Hsiegn’s formula for vertical vibrations. [6]
8. (a) List the basic differences in analyzing a reciprocating machine foundation by
the 2 approaches namely [8]
i. Linear weightless spring-mass system, and
ii. Elastic half-space theory.
(b) Derive the expressions of natural frequency and amplitude of a block founda-
tion subjected to vertical vibration.

Earning:   Approval pending.