Implementation of Displacement Coefficient method for seismic assessment of buildings built on soft soil sites

This paper presents the results of an investigation aimed at extending the Coefficient Method for the seismic assessment of existing buildings built on very soft soil conditions. In the first part of this investigation, the lateral displacement response of four steel frames and six reinforced concrete frames under a set of 20 earthquake ground motions recorded on very soft soil sites of the old bed-lake of Mexico City is investigated. It is shown that the seismic response of the buildings strongly depends on the ratio of the first-mode period of vibration of the structure to the predominant period of the ground motion (T/Tg). In the second part of this study, a Displacement Coefficient method approach is employed for obtaining estimates of maximum inelastic roof displacement demands. Error statistics indicates that the Coefficient Method provides reasonably good estimates.