Avaliação da nova formulação para capacidade ao cisalhamento diagonal de alvenaria estrutural

Abstract

This study presents a comparative analysis between the shear strength equation included in the proposed revision of the ABNT standard for structural masonry and the methodology currently prescribed by NBR 16868:2020. The study evaluated 147 walls, including a parametric analysis of a generic wall subjected to varying conditions regarding grouting ratio, vertical reinforcement layout, block strength, mortar strength, and pre-compression level. Additionally, walls from three actual structural masonry buildings—provided by a structural design firm—were analyzed. To simplify the comparative analyses, fixed parameters were adopted for certain variables. The results indicated that the NBR 16868:2020 methodology tends, in several instances, to yield higher shear strength values ​​than those obtained via the proposed revision, particularly for walls with little or no grouting. It was found that explicitly accounting for the masonry's contribution, the pre-compression effect, the dowel action of the reinforcement, and the walls' geometric characteristics significantly influences shear strength. Thus, it is concluded that the proposed revision is more sensitive to the underlying resistance mechanisms, leading to more representative estimates of the structural behavior of masonry walls.