Location

San Diego, California

Session Start Date

5-24-2010

Session End Date

5-29-2010

Abstract

Recent researches have shown that piles are laterally unsupported in liquefiable soils during most strong earthquakes. If this unsupported length is significantly large, the high axial load on piles may make them more vulnerable to buckling instability. Calculation of buckling instability requires the full unsupported length of pile, which is the sum of pile length above the ground, pile length in the liquefied soil and a depth of fixity below the liquefied soil layer. In this paper, the length of fixity of pile foundations embedded in liquefiable soils has been investigated using a simple numerical method. The finite element program SAP2000 V12 has been used to carry out the parametric analysis. The soil has been modeled using Winkler spring approach, which models the lateral restraining effect of the soil as a set of discrete one-dimensional spring distributed along the length of the pile. The buckling loads of the piles embedded in the soil are evaluated using the eigenvalue analysis. The results are then compared and validated with previous analyses based on empirical, analytical and numerical methods. The sensitivity of the buckling load of the embedded piles are studied with respect to the factors such as the depth of liquefaction, the stiffness of the liquefied soil and the unsupported length of the pile, and the results are discussed.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

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

Meeting Name

Fifth Conference

Publisher

Missouri University of Science and Technology

Publication Date

5-24-2010

Document Version

Final Version

Rights

© 2010 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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May 24th, 12:00 AM May 29th, 12:00 AM

Fixity of Piles in Liquefiable Soils

San Diego, California

Recent researches have shown that piles are laterally unsupported in liquefiable soils during most strong earthquakes. If this unsupported length is significantly large, the high axial load on piles may make them more vulnerable to buckling instability. Calculation of buckling instability requires the full unsupported length of pile, which is the sum of pile length above the ground, pile length in the liquefied soil and a depth of fixity below the liquefied soil layer. In this paper, the length of fixity of pile foundations embedded in liquefiable soils has been investigated using a simple numerical method. The finite element program SAP2000 V12 has been used to carry out the parametric analysis. The soil has been modeled using Winkler spring approach, which models the lateral restraining effect of the soil as a set of discrete one-dimensional spring distributed along the length of the pile. The buckling loads of the piles embedded in the soil are evaluated using the eigenvalue analysis. The results are then compared and validated with previous analyses based on empirical, analytical and numerical methods. The sensitivity of the buckling load of the embedded piles are studied with respect to the factors such as the depth of liquefaction, the stiffness of the liquefied soil and the unsupported length of the pile, and the results are discussed.