Numerical study on Role of Shear Key in Precast Beam to Beam Connection Subjected to Torsion

Connections play an important role in behaviour of precast concrete structures. It is also observed that the failure of precast building took place because of connection failure. Generally connection between precast elements are designed for axial force, shear force and bending moment. But when the precast beam supports precast slab of different span on both the side, torsional moment cannot be neglected. Therefore, it is important to study the behaviour of precast connections under the effect of pure torsional loading. In this paper effectiveness of shear key on behaviour of precast beam to beam connection under pure torsion is presented. A numerical simulation is carried out to investigate the torsional behaviour of three different type of precast wet connections with and without shear key using Finite Element Method based software ABAQUS. Projected longitudinal reinforcement of precast beam elements are welded after their erection and the gap is filled with concrete. The damaged plasticity model is employed for modelling the behaviour of concrete and elastic perfectly plastic models are employed for the modelling of behaviour of steel reinforcement. A prefect bond is assumed between the steel reinforcement and concrete. The damage along cracks, are modelled through concrete damage parameters. Precast beam connection with out shear key is considered as control beam. While other beam to beam connections have shear key of different configuration. Torque v/s twist behaviour and damage patterns as obtained from numerical analysis of different precast beam connections with shear key are compared with control specimen. Analysis results exhibited enhanced torsional strength of precast beam connection with shear key in comparison of connection without shear key.