SITE-CITY INTERACTION

摘要

This paper focuses the seismic site-city interaction in Mexico City like environment. It is based on analytical model which reproduce separately the building motion including soil-structure interaction and the feed-back of building vibration into the soil. The urban environment studied corresponds to the Roma Norte district of Mexico City, one of those which suffered lot of damages during the 1985 Mexico earthquake. Analytical results contribute to explain partially the anomalous long time duration and monochromatic beatings systematically observed on the ground motion recorded in the Mexico City's lacustrian zone since 1985. Included in this paper are parametric analysis based on energetic considerations, performed in order to evaluate the main parameters of the urban environment controlling the site-city effect. A rough analytic relationship is then developed to quantify this effect, which depends on the urban density, on the mass ratio and on the resonance criterium between the soil and the city. This confirms the importance of the seismic Site-City Interaction and the need to account it for risk and hazard analysis in urban area.