Exploring the impact of spatial variation of material properties on seismic behavior of URM walls with openings via computational modeling

Abstract

The mechanical properties of unreinforced masonry (URM) wall constituents (i.e., brick, mortar, and unit-mortar interface) vary considerably due to their inherent nature and manufacturing process. In this context, the present study explores the impact of material uncertainty related to the tensile bond strength, friction angle, and masonry compressive strength by considering their spatial variation. A recently proposed computational modeling approach is used throughout this study, called probabilistic discrete rigid block analysis (D-RBA). The masonry texture is represented using a system of rigid blocks interacting along their boundaries. In the proposed modeling strategy, unit-mortar interfaces are explicitly simulated, and failure mechanisms (e.g., joint openings, sliding, and crushing) are considered at the contact points defined among adjacent blocks. The adopted computational framework predicts and characterizes variations in the ultimate load and drift capacity of URM walls with openings and the associated failure mechanisms. The results indicate the advantageous feature of probabilistic D-RBA when the spatial variation of mechanical properties of the URM system is considered. D-RBA provides a more realistic representation of the existing condition of the URM walls and offers less uncertainty in the numerical predictions compared to non-spatial probabilistic analysis. The implementation of D-RBA can thus enhance the decision-making process in seismic assessment and retrofitting old masonry buildings.