Nonlinear seismic response and index correlation of high arch dams under cross-stream oblique incidence of near-fault SV waves based on wavelet decomposition

Abstract

This paper aims to propose an analysis framework for the response index correlation of high arch dams under cross-stream oblique incidence of near-fault pulse-like and non-pulse seismic waves. The influence of the dynamic pulse effect of near-fault seismic waves on the index correlation at different incidence angles is evaluated. Further, the seismic response through an arbitrary incident angle is quantitatively estimated. Several typical near-fault records of extracted strong velocity pulses are selected, and their decomposed non-pulse ground motions (GMs) are used to ensure the similarity and uniformity of the response spectra. Furthermore, a seismic input model of the oblique incidence of the SV wave is established based on the three-dimensional viscous-spring artificial boundary method, and its accuracy was confirmed through the numerical application. The engineering demand parameters (EDPs) of pulse-like SV waves and non-pulse SV waves, including dam damage, dynamic displacement, and joint opening, with cross-stream incident angles are discussed emphatically. Finally, the correlation between the response indices of near-fault SV waves at different incident angles is quantitatively analyzed. The numerical results indicate that pulse-like seismic waves with different input angles are more destructive than non-pulse seismic waves, and different response indices of the dam may have different most unfavorable incident angles. A prediction model of the dam response considering different input angles of seismic waves is proposed to roughly estimate the response index values of each input angle. The influence of the dynamic pulse characteristics on the correlation degree of response indices under different input angles is mainly divided into three types: no impact, increasing correlation degree, and decreasing correlation degree. In the seismic design and performance evaluation of arch dams, it should be suggested to comprehensively consider the influence of the oblique incident angle of GMs and near-fault pulse characteristics.