Project:  Dynamic Stiffness of Piles in Liquefiable Soils

PI(s):  Steve Kramer, and Pedro Arduino

Sponsor:  WSDOT

Objective:   To develop a simple, practical constitutive model that can model cyclic mobility in liquefiable soils, to investigate the influence of cyclic mobility on soil-pile interaction, to develop a numerical analysis of pile-soil interaction that accounts for the effects of cyclic mobility, and to use that numerical analysis to develop a series of charts for estimation of pile stiffness for common soil and pile conditions.

Research Approach: The research would make use of the Washington Pile Model (WPM), a recently developed nonlinear, effective-stress based model for the dynamic response of piles subjected to lateral spreading, to investigate pile-head stiffness and damping characteristics. The WPM would be extended by allowing a multiple-degree-of-freedom structure to be connected to the pile and by including and existing plasticity-based soil constitutive model that provides and improved representation of contractive and dilative soil behavior.

This research would allow more accurate evaluation of bridge foundation stiffness and damping characteristics. This would produce greater reliability of structural designs and would reduce the costly overconservatism that is currently required.

For more information send E-Mail to: kramer@u.washington.edu, or parduino@u.washington.edu