Reliability of the maximum displacement ratio in nonlinear static procedure for near-fault sites

The nonlinear static procedure (NSP) has become a popular approach among practitioners for preforming performance based seismic design (PBSD) of buildings. However, researches show that this method can yield unconservative estimations of system responses. It indicates that, even though NSP has been accepted by seismic standards such as ASCE 41-17 as an alternative to the rigorous nonlinear dynamic procedure (NDP), it should be used with caution. In this paper, the accuracy of the maximum displacement ratio coefficient, which is a modification factor in ASCE 41-17 nonlinear static procedure, is evaluated for near-fault zones. This coefficient is meant to relate expected maximum inelastic displacements to displacements calculated for linear elastic response. In order to investigate the accuracy of this coefficient, ten near-fault earthquake records with forward directivity are considered. By performing nonlinear time-history analyses (NTHAs) on SDOF systems with various strength ratios, true values for this coefficient are evaluated. Comparison of NTHA-based results with those obtained from ASCE 41-17 formulations show that ASCE 41-17 formulation is not reliable for near-fault sites

Keywords:

Nonlinear static procedure , Performance based seismic design , Near-fault sites , Pushover analysis