JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD

Pre Requisites

Soil Dynamics

Course Objectives

To understand the wave propagation in soils, determine dynamic

properties of soil for analyzing and designing foundations subjected to vibratory loading.

Course Outcomes

At the end of the course, the student will be able to:

• Understanding the fundamentals of vibration wave progression and dynamic soil properties
• Design machine foundations resting on soils

UNIT - I

Fundamentals of Vibration: Definitions, Simple harmonic motion, Response of SDOF systems of Free and Forced vibrations with and without viscous damping, Frequency dependent excitation, Systems under transient loads, Rayleigh’s method of fundamental frequency, Logarithmic decrement, Determination of viscous damping, Transmissibility, Systems with Two and Multiple degrees of freedom, Vibration measuring instruments.

UNIT - II

Wave Propagation and Dynamic Soil Properties: Propagation of seismic waves in soil deposits - Attenuation of stress waves, Stress-strain behaviour of cyclically loaded soils, Strength of cyclically loaded soils, Dynamic soil properties - Laboratory and field testing techniques, Elastic constants of soils, Correlations for shear modulus and damping ratio in sand, gravels, clays and lightly cemented sand. Liquefaction of soils: An introduction and evaluation using simple methods.

UNIT - III

Vibration Analyses: Types, General Requirements, Permissible amplitude, Allowable soil pressure, Modes of vibration of a rigid foundation block, Methods of analysis, Lumped Mass models, elastic half space method, elasto-dynamics, effect of footing shape on vibratory response, dynamic response of embedded block foundation, Vibration isolation.

UNIT - IV

Design of Machine Foundations: Analysis and design of block foundations for reciprocating engines, Dynamic analysis and design procedure for a hammer foundation, IS code of practice design procedure for foundations of reciprocating and impact type machines. Vibration isolation and absorption techniques.

UNIT - V

Machine Foundations on Piles: Introduction, Analysis of piles under vertical vibrations, Analysis of piles under translation and rocking, Analysis of piles under torsion, Design procedure for a pile supported machine foundation.

R16 B.TECH CIVIL ENGG.

TEXT BOOKS:

• 1. Swami Saran – Soil Dynamics and Machine Foundations, Galgotia Publications Pvt. Ltd.
• 2. Principles of Soil Dynamics, Das, Braja M., and Ramana G.V. 2nd Edition, Cengage Learning Engineering Publishers, 2010
• 3. Kameswara Rao, N.S.V. – Vibration Analysis and Foundation Dynamics, Wheeler Publication Ltd. 1998.

REFERENCES:

• 1. Prakash, S. and Puri, V. K. - Foundation for Machines: Analysis and Design, John Wiley & Sons, 1998.
• 2. Prakash, S. - Soil Dynamics, McGraw Hill, 1981. R16 B.TECH CIVIL ENGG.