A influência das ações de vento e sísmicas no dimensionamento de edifícios de alvenaria estrutural de múltiplos pavimentos

Abstract

Although seismic actions are not yet routinely considered in the design of structural masonry buildings in Brazil, the publication of ABNT NBR 15421:2023 introduced criteria for accounting for these actions in such structures. In this context, this study aimed to investigate the influence of building height on the design of structural masonry buildings subjected to wind, out-of-plumb, and seismic actions. To this end, two buildings with the same architectural configuration, comprising four and twelve stories, were analyzed for Site Class D and all Brazilian seismic zones, using seismic response modification coefficients R = 1.5 and R = 3.0. The design criteria of the current standard were also compared with those of the Draft Revision of ABNT NBR 16868-1. The analyses included the distribution of horizontal actions; structural verifications for shear, compression, and flexural tension; and an assessment of the reinforcement required in the critical wall, as well as the number of walls failing the seismic design checks relative to those governed by wind and out-of-plumb actions. The results indicated that, for the buildings analyzed, seismic actions had a greater influence than wind and out-of-plumb actions, with this difference being more pronounced in the twelve-story building. Furthermore, the Draft Revision generally resulted in a more conservative design for shear and flexural tension checks, increasing the number of walls requiring reinforcement. It is concluded that considering seismic actions through the Equivalent Lateral Force (ELF) method can significantly affect the design of structural masonry buildings, even in regions of low seismicity, and that, for the structural configuration investigated, the twelve-story building exhibited greater sensitivity to seismic effects than the four-story building.