Author(s)

J. A. Avila

Abstract

The damage levels observed in the field, due to the 1985 earthquakes, is compared in a building in Mexico City with the analytical predicted behavior with, and without, the available over-resistance effects. The results were compared to those obtained from the conventional seismic analysis and to the observed damage behavior after the earthquake. Even the structures behaviour, located in soft soil in Mexico City, are qualified as adequate; there were some problems in some buildings, especially those between 7 to 17 levels. The structures behavior shows that these count with a certain over-resistance range that has been indirectly included and that was possibly the reason that a great number of buildings have not collapsed, even though they suffered severe damage. Elastic and inelastic time-history analyses are made. The soil-structure interaction and the P-∆ effects are included in the analysis. The analytical periods are compared to those experimentally obtained. A very good congruency between the analytically predicted behavior and the observed damage level after the earthquake is obtained. The direction and the stories with maximum damage match with the direction and stories with maximum deformations obtained from the analysis. The structural element resistances determined in a nominal way result were quite low compared to their real average values. It is noticed that the structure has a superior lateral resistance capacity compared to that given in the conventional design. 1 Introduction Even the behavior of structures located in the soft zone in Mexico City, and subject to the 1985 earthquakes, are qualified as satisfactory; there were some

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