Report - PEER - University of California, Berkeley

SOME DEVELOPMENTS ON PERFORMANCE-BASED SEISMIC DESIGNOF MASONRY STRUCTURESSergio M. ALCOCER 1 , Juan G. ARIAS 2 and Leonardo E. FLORES 3ABSTRACTPerformance-based earthquake engineering aims at improving the seismic-risk decision-makingprocess through assessment and design methods such that a building attains specific levels ofperformance under given specified earthquake demands. Masonry design and construction havebeen traditionally developed on an empirical basis; until recently, improvements had beenattained through a trial-and-error process, more than through rigorous mechanics principles andmodels. Current prescriptive assessment and design methods fail to describe most commonlimit states accepted for structures made of other materials. In this paper, current designpractices and new approaches under development, based on experimental data from static anddynamic tests, are presented. To assess the seismic performance of typical Mexican confinedmasonry houses, results of a series of shaking table underway are included. A performancecriteria and a simple analytical model, aimed at predicting the nonlinear response of masonrystructures, are introduced. Measured and calculated responses are compared to evaluate theadequacy of modeling assumptions. Differences indicate the need of improvement of nonlinearmodeling of complex confined masonry walls.Keywords: Confined masonry; Walls; Design; Limit states; Testing; and Evaluation.1.1 Housing in Mexico1. INTRODUCTIONAs many other countries, Mexico experiences a very large housing deficit that hasaccumulated over decades. Limited economic growth and scarce financial incentivesin the country have been two of the primary reasons for the estimated 4.3 millionhouses that need to be either built or refurbished. Although the deficit is concentratedin urban areas, rural villages experience much of the same problems, but with more1 Director, Institute of Engineering, UNAM, Apartado Postal 70-472, Mexico DF, 04510,salcocem@iingen.unam.mx2 Research assistant, Institute of Engineering, UNAM, Apartado Postal, 70-472, Mexico DF, 04510,jara@iigen.unam.mx3 Researcher, National Center for Disaster Prevention, CENAPRED, Av. Delfin Madrigal 665, Mexico DF,04360, Ifc@cenapred.unam.mx233