Behavior of pile foundations in liquefied and laterally spreading ground. eScholarship
ASCE/AEG/UMKC Geotechnical Conference April 6, 2002 University Center, Pierson Auditorium University of Missouri at Kansas City Behavior of Pile Foundations in Liquefied and Laterally Spreading Ground By Priyanshu Singh 1 Scott J. Brandenberg 1 Ross W. Boulanger 2 Bruce L. Kutter 3 ABSTRACT Methods for predicting the performance of pile foundations in liquefying and laterally spreading ground during earthquakes have developed considerably in recent years. Nonetheless, the mechanisms of soil pile interaction in liquefied soil are still not well understood and the accuracy of design methods remains to be quantified. Subsequently, a series of dynamic centrifuge model experiments are being performed at UC Davis to study the behavior of single piles and pile groups in a soil profile comprised of a nonliquefied crust spreading laterally over a loose saturated sand layer. This paper will discuss some recent findings on the lateral resistance of liquefied soil, present initial evaluations of simplified pushover design methods against centrifuge test data, and summarize current recommendations for engineering practice. INTRODUCTION Extensive damage to pile supported structures in areas of liquefaction and lateral spreading has been observed in many earthquakes around the world. A review of case histories and physical modeling studies shows that many important lessons and insights have been learned in recent years, but that numerous questions remain regarding the mechanisms of soil pile interaction in liquefied soil for many situations. In addition, the accuracy of our evolving design methods remains to be quantified. Predicting the behavior of a pile foundation in liquefying ground during an earthquake requires consideration of design motions, free field site response, superstructure response, and soil pile superstructure interaction. Evaluating pile performance requires consideration of the inertial and kinematic loads imposed on the piles and their pile cap connections, transient or permanent deformations of the pile foundation, the influence of the pile foundation on the dynamic Graduate student, Dept. of Civil Environmental Engrg. University of California, Davis, CA. Associate Professor, Dept. of Civil Environmental Engrg. University of California, Davis, CA. Professor, Department of Civil Environmental Engineering, University of California, Davis, CA.