STUDY OF SEISMIC VULNERABILITY OF SOCIAL HOUSING WITH THIN RC BEARING WALLS IN THE COAST OF PERU

In recent years, the Peruvian government has promoted the development of social housing projects with thin RC shear walls of limited ductility to overcome the housing deficit in popular sectors of the population. This structure system consists in 10 cm thick walls that have a single central reinforcing mesh that allows a lower cost of construction compared to traditional systems. However, there are no records of its performance to seismic events for two reasons: these new social housing began to be constructed from the year 2000 and there is a seismic silence since 1974 for the central coast of Peru. In addition, performance of this type of buildings has been studied through the fragility curve for the collapse limit state of a simplified model and the vulnerability curve based on expert opinion. The objective of the research is to contribute to improving the safety of peruvian housing through the analytical study of the seismic vulnerability of social constructions with thin RC bearing walls. The typology was first characterized by two representative models: a single-family dwelling of 2 floors and a multi-family building of 5 floors. Both typologies were represented by nonlinear models performed and calibrated with laboratory damage tests. Then, the models were evaluated to seismic demands characteristic of the central coast of South America by means of an Incremental Dynamic Analysis (IDA). Fragility structural curves were obtained for the limit state of collapse. Finally, the seismic performance of both typologies was obtained through vulnerability curves estimating the expected repair cost, based on the FEMA 58 report. The damage states associated to repair techniques costs of the walls were obtained from cyclic lateral load tests for controlled displacements carried out at the Pontifical Catholic University of Peru for SENCICO. For frequent and occasional earthquakes, imperceptible fissures due to flexion and shear predominated. For earthquakes of greater intensities structural damages is more evident. Repair techniques proposed by SENCICO are economically feasible because they represent in average 50% of the reconstruction cost for a very rare earthquake for the typology of 5 floors and 10% reconstruction cost for the 2-story typology. Next steps could be life cycle cost-benefit analysis to assess the economic losses of the typology of social housing and the elaboration of repair plans after a seismic event.