Location

Arlington, Virginia

Session Start Date

8-11-2008

Session End Date

8-16-2008

Abstract

Pile foundations are regarded as a safe alternative for supporting structures in seismic areas. The performance of piles depends on soil profile, pile and earthquake parameters. The soils may also be prone to liquefaction. In non-liquefying soils the shear modulus degrades with increasing strain or displacements. Material damping increases with increasing strain or displacement. Stiffness of single pile and pile groups are needed for different modes of vibration; e.g., vertical vibrations, horizontal sliding in x or y direction, rotation about x or y axis and torsion. Group action is generally accounted for by including interaction factors. Pile response in any mode of vibration is determined from principles of structural dynamics. In liquefiable soils, the liquefaction may lead to substantial increases in pile cap displacements above those for the non-liquefied case. Down-drag due to liquefied soil may also pose problems. After liquefaction, if the residual strength of the soil is less than the static shear stresses caused by a sloping site such as a river bank, lateral spreading or down slope displacements may exert damaging pressures against the piles as observed during the 1964 Niigata and the 1995 Kobe earthquakes. The paper presents state of the art on analysis and design of piles subjected to seismic loading.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Sixth Conference

Publisher

Missouri University of Science and Technology

Publication Date

8-11-2008

Document Version

Final Version

Rights

© 2008 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Aug 11th, 12:00 AM Aug 16th, 12:00 AM

Design Prediction and Performance of Piles for Seismic Loads

Arlington, Virginia

Pile foundations are regarded as a safe alternative for supporting structures in seismic areas. The performance of piles depends on soil profile, pile and earthquake parameters. The soils may also be prone to liquefaction. In non-liquefying soils the shear modulus degrades with increasing strain or displacements. Material damping increases with increasing strain or displacement. Stiffness of single pile and pile groups are needed for different modes of vibration; e.g., vertical vibrations, horizontal sliding in x or y direction, rotation about x or y axis and torsion. Group action is generally accounted for by including interaction factors. Pile response in any mode of vibration is determined from principles of structural dynamics. In liquefiable soils, the liquefaction may lead to substantial increases in pile cap displacements above those for the non-liquefied case. Down-drag due to liquefied soil may also pose problems. After liquefaction, if the residual strength of the soil is less than the static shear stresses caused by a sloping site such as a river bank, lateral spreading or down slope displacements may exert damaging pressures against the piles as observed during the 1964 Niigata and the 1995 Kobe earthquakes. The paper presents state of the art on analysis and design of piles subjected to seismic loading.