Análise da influência de ligações semi-rígidas no desempenho estrutural de sistemas pré-fabricados

Abstract

The present study aims to analyze the impacts of beam–column joint stiffness on the structural behavior of a three-story building constructed with precast elements. To this end, numerical simulations were carried out using the SAP2000 and TQS PREO software, which allow the assessment of structural behavior through nonlinear static pushover analysis and the verification of global stability coefficients, as established by NBR 6118:2023. The structure was modeled with rigid, pinned, and semi-rigid connections, adding stiffness at points defined as relevant to the structure. This made it possible to observe how different stiffness levels influence the global behavior of the structure, the displacements, and the formation of plastic hinges. In addition to stability-related aspects, the internal forces resulting from each scenario were also analyzed. The results showed that the adoption of semi-rigid connections at the selected nodes led to an increase of approximately 148% in the maximum shear force obtained in the pushover analysis and to a maximum displacement about 20% higher compared to the fully pinned model. While in the pinned model the plastic hinges were concentrated at the bases of the columns, with low capacity for force redistribution, the semi-rigid model also mobilized the beams as energy-dissipating elements, resulting in a more distributed lateral collapse mechanism and improved ductile performance. These results reinforce the importance of carefully considering joint behavior in the design of precast structures, since connection stiffness directly influences both the load bearing capacity and the ductility of the structural system.