ABSTRACT
Most seismic designs of mat foundations on clayey deposits are carried out considering only the aspects of bearing capacity, using the concept of load excentricity. Settlements induced by seismic loading are seldom considered mainly because it has been believed that they are of low relevance on the basis of the few case histories reported in the literature. This way of thinking was proved wrong by the significant number of cases that developed in Mexico City during the September 19. 1985 seismic event, where mat foundations on clay deposits underwent large plastic displacements that caused damage beyond any repair to the buildings they supported.
In this paper, the main features of a procedure based on limit equilibrium that allows computation of plastic displacements induced by earthquakes on mat foundations are presented and its capabilities are evaluated throughout comparisons with an actual case.
