DETERMINACIÓN DE CURVAS DE FRAGILIDAD DE UN EDIFICIO DE MARCOS DE CONCRETO REFORZADO, PARA DETERMINADAS EXCITACIONES SÍSMICAS

Abstract

The continued occurrence of earthquakes in our country has left teaching that we must study and analyze, and to mitigate the seismic risk that our buildings are exposed. The fragility curves are one of the most recalled and useful techniques to perform such studies. The fragility curves provides in a simple format the cumulative probability to experiment or to exceed a state of maximum response of the structure, when it is subjected to earthquakes of a certain intensity. In this work, a methodology and its application for the generation of fragility curves is proposed for a tipycal building. The general procedure is described below: First, it is important to know and to define the seismic demand schemes at which the structure will be subjected. In this work, by considering that in most cases there are no seismic records as available and enough as it is desired to represent the overall danger, it is proposed the use of seismic simulation techniques. For this purpose, around 1000 synthetic accelerograms were generated for each of the magnitudes between the thresholds of 7.1° to 8.4° based on the Richter scale. That means that 14,000 total synthetic earthquakes were generated. Subsequently we define a structural model to represent the mechanical behavior of the building. Here we use a numerical model built with elements beam-column. A nonlinear material model It is also used to represent the reinforced concrete behavior. With these models, non-linear dynamic analysis were performed based on the seismic demand already established, andfor each one of the synthetic accelerograms. To analyze the response of the building, an index that determines the level of possible damage to the structure is required. Because the structural and some nonstructural components are sensitive to relative movement between different levels produced during earthquakes, In the present work, the drift was established. In addition, this parameter is used to examine the response of structures in different seismic design standards, which greatly facilitates the implementation of the results. Finally, the fragility curves can be generated from the information of the simulated responses through the statistical analysis and the application of probabilistic concepts. The principal contribution of this paper, was propose a methodology for generate curves of fragility, from statistical methods and probabilistic, of a building of reinforced concrete, however, this methodology could be improved, by considering variations in the strength of materials.