Análise numérica de conectores de cisalhamento do tipo tubular Perfobond com furo alongado

Abstract

Composite steel-concrete beams combine the properties of these two materials to provide superior structural performance. However, ensuring the bond between steel and concrete is essential, with the most common method being the use of shear connectors, which are responsible for the mechanical connection between the two materials. Structural codes recommend the use of stud and U-profile connectors. However, new versions of these codes are being developed, considering other types of connectors for design purposes. The Perfobond connector has stood out for its strength, but in some cases, its slip capacity is unsatisfactory. Therefore, the Tubular Perfobond shear connector has been investigated as an alternative to the traditional Perfobond, aiming to provide greater ductility and resistance. This study focused on the numerical evaluation of Tubular Perfobond connectors, based on the validation of experimental tests of pre-existing similar connectors, as no tests with Tubular Perfobond connectors were found in the literature. A parametric analysis was also performed, varying the main parameters that could impact the structural behavior of this connector type, primarily the influence of two holes geometries, one with a circular hole and the other with an elongated hole. Three distinct failure modes were observed: tensile failure due to slab cracking, compressive failure due to concrete crushing, and connector yielding connectors with two circular holes failed by tension due to slab cracking, while those with elongated holes failed due to simultaneous concrete crushing and connector yielding. The results generally demonstrated that increasing the concrete strength significantly impacts the connector resistance. Modifying the hole geometry from circular to elongated, as well as using thinner connectors, reduced resistance but increased the slip capacity of the models. Based on the observed results, a formulation was developed to determine the load capacity of this connector type, along with a practical design example. The proposed prescription in this work showed good agreement with the values obtained in the numerical modeling, proving to be safe and effective in predicting not only the load capacity but also the failure mode, thus avoiding undesirable failure cases. Additionally, the change in hole geometry from circular to elongated led to a shift in the failure mode from brittle to ductile, in most cases. Therefore, it can be concluded that the Tubular Perfobond connector is a viable alternative to the traditional Perfobond in terms of strength and ductility.