Seismic Response Parametric Study of Ancient Rocking Columns

Abstract

ABSTRACTThis study examines the seismic response of free-standing, monolithic rocking columns, taking into account different ground motion intensity measures (IMs). The primary scope of this article is to investigate the effect of the IMs, among 23 considered, on the rocking response of the examined structural system. The seismic vulnerability of the examined structural systems is based on the probabilistic seismic demand model (PSDM), in which the degree of uncertainty depends on the used IM. Thus, concluding to the most efficient one is of major importance. A performance-based analysis has been performed, using three limit states, and fragility curves are generated in terms of the most efficient univariate and bivariate IMs, considering the maximum rocking rotation normalized to the critical overturning rotation, as engineering demand parameter. Time domain analyses are numerically performed, by solving the equation of rocking motion, given a set of 35 natural seismic records. The results indicate that the velocity based as well as the frequency content IMs exhibit a strong correlation with the seismic behavior of free-standing rocking columns. Moreover, the acceleration based IMs can describe with great efficiency the rocking response only as a bivariate IM combined with the frequency content of the ground motions.