Performance of partially grouted reinforced masonry walls with bed-joint reinforcement: parametric and optimization investigation

Post-seismic assessments have indicated that the responses of masonry walls to seismic forces may be classified into two key categories: in-plane global mechanisms and out-of-plane cyclical actions occurring orthogonally to the wall. The initial phase of this investigation scrutinized the widely accepted shear strength models for in-plane shear resistance, V-n, of reinforced masonry (RM) walls. Subsequently, using a dataset comprising 78 samples of fully grouted hollow concrete block (HCB) RM walls, a detailed examination of the sensitivity of experimental shear strength, V-exp, to geometric, mechanical, and reinforcement characteristics of the wall was undertaken. The study's second phase entailed a parametric evaluation using finite element analysis to appraise the sensitivity of lateral drift to wall geometry and bed-joint reinforcement attributes. The third phase of the research introduced an informational model for estimating the lateral drift of partially grouted RM walls, incorporating BJ and vertical reinforcement. The model was established utilizing data from 44 full-scale in-plane cyclic tests on clay brick walls and 32 tests on HCB walls. The investigation further presented a multi-objective optimization methodology to ascertain the optimal vertical and BJR ratios, rho(v) and rho(BJ). A graphical user interface and an accompanying empirical equation were also devised to simplify the analysis and design process for reinforced masonry walls, obviating the need for lengthy analyses. Increasing the BJR size from 6 to 8 mm resulted in a 30% increase in V-n for specimens with six BJR rows, while increasing the number of BJR rows from six to ten led to 16% rise in V-n, as demonstrated by numerical modeling validated against experimental tests.The findings of the study highlight a notable dependence of the lateral drift capacity of reinforced masonry walls on wall geometry and rho(BJ) ratio. These revelations provide invaluable insights for designing earthquake-resistant masonry edifices and formulating rehabilitation strategies for existing masonry structures deficient in seismic resilience.