Empirical fragility assessment of adobe and rammed earth walls subjected to seismic actions

Abstract

AbstractIn many Latin American countries, most constructions from the colonial period were built in earth masonry. During past earthquakes, some of these buildings collapsed even with moderate magnitude events resulting in significant loss of human lives. Nevertheless, empirical fragility functions at the component level (FFs) for these structures have not been comprehensively investigated in the literature. This paper presents the probabilistic characterization of the uncertain damage sustained by earthen vertical wall segments subjected to seismic actions. Drift‐based FFs are constructed for in‐plane (IP) actions using 48 test results from previous studies. Three damage states, corresponding to cracking, extensive cracking, and collapse, are proposed for this loading direction. Only the collapse state is analyzed for out‐of‐plane (OOP) forces and a total of 26 experimental results comprise the database for this case; peak ground acceleration is selected to represent the intensity measure for OOP demands. Analysis of variance (ANOVA) tests aided to confirm that, for in‐plane demands, the compressive strength is one of the most influential parameters for the cracking limit state. ANOVA tests also helped to identify that only the slenderness and boundary conditions seem to have a slight influence in the FFs for the OOP demands. Finally, the derived FFs were used to recommend drift and acceleration‐based limit states for earthquake‐resistant assessment of earthen components. The developed fragility functions may be used to predict the probability of occurrence of a certain damage state at a component level which can be used in risk and resilience assessments of vernacular buildings.