Estudo dos efeitos localizados de segunda ordem em paredes de contraventamento de edifícios de alvenaria estrutural

Abstract

The present study consists of the evaluation of local second order effects on unreinforced shear walls in structural masonry through a numerical approach using the Finite Element Method. For this purpose, an adaptation was made to the equivalent frame model to simulate the out-ofplane response of selected shear walls on storeys of a building. The validation of the new model was performed by comparing its results with those obtained from an experimental model for slender walls in which a flexion out-of-plane of the walls was mobilized. The shear walls were modeled in three configurations: completely modeled shear walls under loads applied in full extension; isolated columns; and completely modeled shear walls under the application of loads separately in each column. The analysis considered the magnitudes of the displacements of the walls, the mobilization of the columns, as well as the second order moments caused by the model’s geometric nonlinearity. Finally, verifications in the design of walls and isolated columns were carried out using the methodologies prescribed in the Brazilian standards NBR 15961-1:2011, NBR 16868-1:2020, and in the Eurocode 6 - PD 6697:2019, with subsequent comparison with the results obtained from numerical modeling. The analysis of the results showed the influence of the lateral support, provide by the transversal walls, on the shear walls’ stiffness, and highlighted the importance of considering the local second order effects in shear walls’ design, whose the required values of compressive strength increased substantially when considering these effects. In addition, it was possible to observe the efficiency of the model developed in the proposed approach, since it presented similar results to those resulting from the prescriptions of NBR 16868-1.