Estudo numérico do comportamento ao cisalhamento de ligações laje-pilar mistas aço-concreto em lajes lisas

Abstract

The use of flat slabs, that is, without beams, has been frequently utilized in reinforced and prestressed concrete structures, presenting advantages such as simplified formwork and the possibility of defining different architectural layouts. Although not as common, the use of flat slabs for steel-concrete composite structures has recently been considered in building projects. In principle, the behavior of the slab is governed by the same phenomena that occur in reinforced and prestressed concrete solutions, where the punching shear of the concrete governs the loadbearing capacity of the structure. Reinforcements with passive transverse reinforcement, such as stirrups and dowels, and the application of prestressing can be considered. In the case of composite structures, with steel and/or composite columns, other types of reinforcement can be designed and installed in the slab-column connection, creating alternatives that may potentially improve the behavior of this type of connection. Focusing on the slab-column connection, a series of numerical studies was carried out using the DIANA FEA software, attributing to it the characteristics of a steel-concrete composite structure. Thus, after obtaining a calibrated model capable of faithfully reproducing the results obtained in experimental programs found in the literature, parametric analyses of a set of flat slabs with symmetrical spans totaling 57 specimens were conducted. For the simulated models, different arrangements of metal plates in the slab-column connection and variations in the geometric parameters of the structure and the mechanical characteristics of the concrete were tested. In this way, it was possible to identify the factors influencing the load-bearing capacity of this type of connection and identify possibilities for system improvement. At the end of the study, a proposal for a formulation to the Brazilian concrete standard was also made to include this type of reinforcement.