Study of local second order effects on shear walls of structural masonry buildings
structural masonry; shear walls; geometric nonlinearity; local second order effects; numerical modeling.
The present study consisted 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-of-plane response of selected shear panels on two 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: complete shear panels under loads applied in full extension; isolated columns; and complete shear panels under the application of loads separately in each column. The analysis considered the magnitude of the displacement of the panels, the influence of the columns, as well as the second order moments caused by the models’ geometric nonlinearity. Finally, verifications in the design of panels 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 British standard BS 5628: 2005, with subsequent comparison with the results obtained from numerical modeling. The analysis of the results showed the influence of the lateral support on the panels’ stiffness, and highlighted the importance of considering the local second order effects in panels’ design, since 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.