ORIGINAL ARTICLE Seismic vulnerability: theory and application to Algerian buildings Ahmed Mebarki & Mehdi Boukri & Abderrahmane Laribi & Mohammed Farsi & Mohamed Belazougui & Fattoum Kharchi Received: 28 January 2013 / Accepted: 7 June 2013 # Springer Science+Business Media Dordrecht 2013 Abstract When dealing with structural damages, under the effect of natural hazards such as earthquakes, it is still a scientific challenge to predict the potential damages, before occurrence of a given hazard, as well as to evaluate the damages once the earthquake has occurred. In the present study, two distinct methods addressing these topics are developed. Thousands (∼54,000) of existing buildings damaged during the Boumerdes earthquake that occurred in Algeria (M w =6.8, May 21, 2003) are considered in order to study their accuracy and sensitiv- ity. Once an earthquake has occurred, quick evaluations of the damages are required in order to distinguish which structures should be demolished or evacuated immedi- ately from those which can be kept in service without evacuation of its inhabitants. For this purpose, visual inspections are performed by trained and qualified engi- neers. For the case of Algeria, an evaluation form has been developed and is still in use since the early 80s: Five categories of damages are considered (no damage or very slight, slight, moderate, major, and very severe/collapse). This paper develops a theoretical methodology that pro- cesses the observed damages caused to the structural and nonstructural components (foundations, roofs, slabs, walls, beams, columns, fillings, partition walls, stairways, balconies, etc.), in order to help the evaluator to derive the global damage evaluation. This theoretical methodology transforms the damage category into a corresponding “residual” risk of failure ranging from zero (no damage) to one (complete damage). The global failure risk, in fact its corresponding damage category, is then derived according to given combinations of probabilistic events in order to express the influence of any component on the global damage and behavior. The method is calibrated on a set of ∼54,000 buildings inspected after Boumerdes earthquake. Almost 80 % of accordance (same damage category) is obtained, when comparing the theoretical results to the observed damages. For pre-earthquake analysis, the methodology widely used around the world relies on the prior calibration of the seismic response of J Seismol DOI 10.1007/s10950-013-9377-0 MSc. A. Laribi passed away in 2011. The first method, devoted to the post-earthquake damage evaluation in the present study, results from the research he was carrying out to prepare his PhD thesis, at USTHB (Algeria) in co-supervision with UPEMLV (France). A. Mebarki (*) Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208, 5 bd Descartes, 77454 Marne-la-Vallée, France e-mail: Ahmed.Mebarki@univ-paris-est.fr M. Boukri : M. Farsi : M. Belazougui National Earthquake Engineering Research Center (CGS), Rue Kaddour Rahim Prolongée, BP.252, 16040 - Hussein Dey, Algiers, Algeria M. Boukri Civil Engineering Department, University Saad Dahlab, Blida, Algeria A. Laribi : F. Kharchi Université des Sciences et Technologie Houari Boumediène, Laboratoire Bâti dans son Environnement, USTHB/FGC/LBE, BP 32, El Alia, Bab Ezzouar, Algeria