Developed approach to determine the seismic vulnerability of reinforced concrete structures

¹ Geo-materials Laboratory, Civil Engineering Department, Faculty of Technology, Saad Dahleb university of Blida, ALGERIA.
² Faculty of Technology, university of Medea, ALGERIA

Abstract

Several evaluation methods of the seismic vulnerability have been developed around the world. Which are very use ful from humanitarian and socioeconomic point of view. Generally these methods use knowledge obtained from previous earthquakes and they are basing on seismic intensity scales and on buildings direct observation. But the macroseismic intensity expresses the consequences of the seism, and not its physical characteristics of the structures. Contrary to this type of methods, an approach based on a nonlinear analysis (Push-Over method) is proposed in this work. It consists in modeling the excitation of the earthquake by a response spectrum and building's behavior by capacity curves. These capacity curves are obtained from numerical modeling performed by Opensees software. The superposition of the two curves, response spectra and capacity curve, makes it possible to determine the performance point and consequently to deduce the state of expected damage. To estimate the probability of damage of a building at a given level of solicitation (defined by S_d), we excites a group of buildings characterized by different parameters related to the geometry of the building and those are related to the materials used (concrete, steel) by seismic solicitation (Response spectrum - RPA 99). The performance point for each building is determined by a procedure defined in FEMA 440. We classifies the buildings according to the position of performance point on their curve which defines a damage state of ds (Mild, Moderate, Important or Ruin) according to the damage levels of Risk-UE. A statistical analysis is then made for each class to build the fragility curves.