Multidimensional functionality limit states for seismic resilience analysis of urban buildings

Currently, most of methodologies available to evaluate the seismic performance of buildings use as index maximum interstory drifts. However, recent earthquakes have evidenced the need to develop performance levels that incorporate seismic resilience concepts to evaluate the level of post-seismic functionality of buildings and their capacity to recover functionality. Furthermore, such performance levels should explicitly consider the performance of structural, non-structural elements and contents. For this purpose, this paper proposes a set of six performance limit states for office-type buildings, in which the seismic performance of structural, non-structural elements and contents is explicitly considered. Each of these limit states is associated with a set of probable events that generically determine its recovery of functionality (e.g., post-seismic inspection and management of financial resources). To exemplify the proposed scheme a seven-story reinforced concrete building with unreinforced infill masonry walls and located in Mexico City is evaluated. The results obtained suggest that the building has a significant probability of experiencing loss of functionality due to the damage suffered mainly by the non-structural elements and contents. This indicates that modern seismic design codes, as that used for this study, accomplish their main objective, which is to reduce the probability of collapse and to prevent the loss of human lives. However, these results also demonstrate that the main objective of decision makers when designing such buildings, which is to be functional for one or several needs, is not achieved.