Estudo numérico dos conectores T-Perfobond com mesa não soldada em vigas mistas de aço e concreto

Abstract

The use of composite steel-concrete structures has become increasingly common in the construction industry due to the efficiency and cost-effectiveness they offer. These structures allow for rapid assembly of their components, capitalizing on the mechanical properties of each material, with steel acting in tension and concrete in compression. The interaction between these materials is essential for the system's performance, and to achieve this, shear connectors are employed. Among the studied connectors, the T-Perfobond stands out, offering excellent resistance but exhibiting relatively low sliding capacity. As research in this area has advanced, it has emerged models with variations that incorporate high sliding capacity, such as the T-Perfobond with non-welded flange. The purpose of this work is to investigate the behavior of the T-Perfobond connector with the unwelded flange through the development of a numerical analysis using push-out tests, identifying the influence of the following variables: concrete strength, flange thickness, web thickness, steel strength, and connector height. In order to validate the proposed numerical models, the results were compared with existing experimental data in terms of load versus sliding and failure modes. Through the parametric analysis, it was concluded that, in most of the cases, both the increase in concrete and steel strength resulted in increased connector resistance, with the variation in concrete strength being more significant. Exceptions are related to failure mode in steel or concrete, where there is a threshold level relative to this gain. The increase in connector height and thickness showed a slight improvement in load capacity due to the high robustness of the connector. In terms of ductility, it was observed that increasing concrete strength led to greater ductility, while increasing steel strength reduced sliding capacity due to the increased transfer of forces to the concrete. Failure modes occurred, in most cases, due to concrete crushing in the frontal region and around the connector, as well as yielding of the connector's web. In situations involving connectors with greater thickness or height, shear cracks emerged. The results of the parametric analysis allowed for comparison with formulations already existing in the literature, revealing a significant discrepancy in terms of load-bearing capacity. As a result, an analytical formulation was developed for calculating the load-bearing capacity of this type of connector, taking into account the various failure modes. The results demonstrated a satisfactory agreement with the values obtained from numerical modeling, falling within the range established by the American standard in terms of structural reliability.