Performance and seismic vulnerability of a typical confined masonry house in Cuenca-Ecuador

Abstract

The extent of damage in a city, in case of strong earthquakes, can be estimated from the results of the seismic vulnerability of its most common construction type. The aim of the present contribution is to determine the seismic vulnerability of a confined masonry building typical of Cuenca, Ecuador. Firstly, the macroscopic properties of masonry are derived from mesoscopic finite analyses of masonry piers. Secondly, the proposed structure is modeled using an equivalent frame method, in which masonry walls are defined as piers or spandrels using a macroelement model. Thirdly, a pushover analysis is performed on the structure; the results of this analysis are used to define an equivalent SDOF system. The properties of the SDOF are used to calibrate a single-macroelement model that characterizes the cyclic behavior of the MDOF model. Both models are capable to reproduce in-plane shear and flexural failure modes. Finally, nonlinear dynamic analyses are performed on the single-macroelement system for different ground motions, which are obtained from natural records (SIMBAD data base) compatible with the Ecuadorian design spectrum for several PGA levels. The maximum displacement of each analysis is compared with defined limit states, the exceedance of a limit state is recorded and then fitted to a fragility function using the maximum likelihood procedure. The proposed methodology presents an option for seismic vulnerability, to use in scenarios where little data is available.