Location

San Diego, California

Session Start Date

3-26-2001

Session End Date

3-31-2001

Abstract

This paper presents model block vibration tests results on two and three layered soil system underlain by rigid layer. Using sand and sawdust in different positions (either at top or at middle or at bottom) and thickness (es) inside a tank, different layered soil bed are prepared and vibration tests are conducted on each prepared bed using Lazan Type oscillator. A large number of response curves (frequency vs. amplitude) are obtained on different layered system. Maximum amplitudes (resonant amplitude) and corresponding frequencies (resonant frequency) are tabulated to study the effect of layering on resonant frequencies. Effects of position and thickness (es) of the layer/layers on natural frequencies are found to be significant, Natural frequency increases significantly due to presence of thin stiff layer at top compared to natural frequency of bottom layer treating it to be half space whereas it decreases significantly due presence of thin soft layer at top. Several other significant observations are made and presented in the paper. Natural frequencies of the soil foundation on different layered soil systems used for the experimental investigations are predicted using static equivalent stiffness of the system and compared with experimental results. Predicted results are found to be in good agreement with the experimental results.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Meeting Name

Fourth Conference

Publisher

University of Missouri--Rolla

Publication Date

3-26-2001

Document Version

Final Version

Rights

© 2001 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

Share

COinS
 
Mar 26th, 12:00 AM Mar 31st, 12:00 AM

Natural Frequency of Vibrating Foundations on Layered Soil System-An Experimental Investigation

San Diego, California

This paper presents model block vibration tests results on two and three layered soil system underlain by rigid layer. Using sand and sawdust in different positions (either at top or at middle or at bottom) and thickness (es) inside a tank, different layered soil bed are prepared and vibration tests are conducted on each prepared bed using Lazan Type oscillator. A large number of response curves (frequency vs. amplitude) are obtained on different layered system. Maximum amplitudes (resonant amplitude) and corresponding frequencies (resonant frequency) are tabulated to study the effect of layering on resonant frequencies. Effects of position and thickness (es) of the layer/layers on natural frequencies are found to be significant, Natural frequency increases significantly due to presence of thin stiff layer at top compared to natural frequency of bottom layer treating it to be half space whereas it decreases significantly due presence of thin soft layer at top. Several other significant observations are made and presented in the paper. Natural frequencies of the soil foundation on different layered soil systems used for the experimental investigations are predicted using static equivalent stiffness of the system and compared with experimental results. Predicted results are found to be in good agreement with the experimental results.