Quantification of site city interaction effect on Response of building in near fault region using Domain Reduction Method

This paper presents the quantification of site-city-interaction (SCI) effects on the dynamic response of buildings and free-field motion using domain reduction method. The simulated physics based broadband near-fault ground motion due to Mw6.5 strike-slip earthquake is being utilized to excite the site-city models using domain reduction method. The two step, domain reduction method, is utilized to reduce the exorbitant computational memory and speed as well as measures have been taken to preserve the ground motion characteristics. A building is incorporated in numerical grid as a building block model (BBM) and its dimension, different modes of vibrations and damping are as per the real building. The dynamic response of site-city models is simulated using both the pulse and non-pulse type motions. The analysis of simulated results reveals that the SCI study using realistic earthquake ground motion has caused a reduction of response of building and free field motion in a wide frequency bandwidth as well as its fundamental frequency. An increase of these reductions has been obtained with decrease of building-damping, fundamental frequency and impedance contrast between the BBM and the underlying sediment. A considerable difference in SCI effects is obtained when site-city model is excited with pulse and non-pulse type near-fault ground motions. Detailed study is carried out in order to find out the terms and conditions under which SCI is beneficial to all the buildings of the city.