The influence of regular openings and pre-compression loading on the in-plane strength parameters of unreinforced masonry shear walls.

This study presents a comprehensive investigation of the in-plane response of unreinforced masonry shear walls with regular openings, under the action of monotonic lateral displacement. Walls are considered with several pre-compression loads as well as different window and door openings configurations. To this end, a group of masonry shear walls built with clay bricks and hydraulic lime-sand mortar was selected featuring regular opening layouts. The micro-modeling approach was utilized by considering complex constitutive laws for materials' nonlinear behavior for capturing damages in elements. Results from the nonlinear analysis of the walls were obtained, including the lateral load capacity of shear walls at different performance points, their lateral displacement, stiffness, ductility capacity, normalized absorbed energy, and the overstrength, force reduction, and response modification factors. Moreover, a full discussion is presented regarding the estimating equations from the ASCE 41–17 code on the maximum shear capacity of the walls including their accuracy to predict the shear capacity of URM walls with openings. It is observed that opening reduces the shear strength of the unreinforced masonry shear wall between 5 and 60% as well as a reduction of 10–85% in its effective stiffness, depending on the intensity of the pre-compression load. Moreover, the code's estimation equations for shear strength of unreinforced masonry shear walls lead to an underestimation. For walls with two or more openings of window or door, the average strength from the upper and lower bound of the code-based strength seems appropriate, considering an intense pre-compression load on the wall. [ABSTRACT FROM AUTHOR]