Estudo paramétrico do conector Perfobond e influência do confinamento do concreto

Abstract

The present work refers to an experimental and numerical study for the Perfobond connector. This work is being undertaken as it has been observed that the different geometric arrangements in which the Perfobond connector is inserted have great influence on its mechanical behavior. Significant variations in ductility, strength and failure mode of the connector observed in the literature can be attributed to the depth and level of concrete confinement in the region of the connection. Therefore, in this work it was adopted a new push test geometry, similar to a pullout test, which allows simulating the connector in both superficial and confined situations. It was observed that confined Perfobond holes with perforating rebar show a secondary resistance stage, which occurs after local failure of the concrete dowel, where the perforating rebar resists nearly the totality of the shear force until it fails. This behavior provides a strength and ductility increase to the connection and is not observed in superficial connections, whose resistant capacity is defined by the local failure of the concrete, which, due to the absence of confinement, immediately damage the surface, causing cracking and spalling of the concrete. In order to generate more data for the formulation of a new design model, a numerical model that reproduces the configuration of the performed tests was built in ABAQUS software. The model was able to accurately simulate performed push tests and then was used to extrapolate the physical and geometric configurations of the experimental prototypes in a parametric study to validate the influence of some properties such as the hole diameter (D), plate thickness (t), rebar diameter (d), and the confinement given by the connector depth inside the concrete (P), and the confinement steel reinforcement rate (Ac).