Quantification of role of impedance contrast in site-city-interaction effects on the responses of buildings and basin

Abstract

This paper presents the role of impedance contrast (IC) at the base of 2D deep elliptical basin (shape-ratio > 0.25) in the site-city-interaction (SCI) effects on both the SH- and SV-wave responses of buildings and basin. The obtained SCI effects in the form of reduction of fundamental frequencies of building (F_02D^SB) and basin (F_02D^B), corresponding amplification and splitting of the bandwidth of fundamental mode of vibrations of both the building and basin corroborates with the findings in the past SCI studies. The F_02D^B of basin and F_02D^SB of building are unaffected by an increase of IC during site-city-interaction, even though, there is an increase of F_02D^B of basin with an increase of IC in the absence of city. A drastic increase of SCI effects on the basin response but only minor increase of SCI effects on the building response with an increase of IC is observed for both the polarizations of the S-wave. However, the rate of increase of SCI effects with IC is more in the case of SV-wave responses of buildings and basin. The obtained larger % reduction of F_02D^B and corresponding amplification in the case of SH-wave responses as compared to those in the case of SV-wave responses may be due to the larger height of B16-buildings compared to B12-buildings used in the SV-wave simulations or due to the buildings behaving as a shear beam for the SH-wave or may be due to both.