Analysis of Seismic Performance for Single Piles from EQWEAP

摘要

Discrete wave equations can be used to monitor pile responses under superstructure loads and earthquake excitations. The procedure of Earthquake Wave Equation Analysis of Pile (EQWEAP) has been suggested to compute seismic pile responses based on wave equation analysis of the pile. Alternative solutions were adopted to model the effects of soil liquefaction and liquefaction induced lateral spreading. Nonlinear moment and curvature relationships of the pile were followed to obtain the corresponding nonlinear pile behaviors. Using EQWEAP analysis, the authors have conducted the Performance Based Earthquake Engineering analysis (PBEEA) for single piles located in Taipei Basin. Simplified procedures were used following the suggestions of Kramer (2008). The hazard curves on PGAs proposed by Cheng (2002) were adopted. Maximum pile displacements recorded at the pile head were obtained as the Engineering Demand Parameter (EDP) for seismic design use. The earthquake effects on piles with return periods of 30, 475 and 2500 years were simulated respectively. It is found that the simplified analysis can provide efficient and fast solutions to evaluate the seismic performance for single piles, and it is extensible for more realistic foundation in which the pile-to-pile interaction and the cap-pile-soil interaction must be included.