Modelling of exterior beam to column joint in ’60-70s RC existing buildings

Beam-to-column joints are commonly considered critic regions for r.c. frames subjected to high-magnitude earthquakes. When designed for gravity loads only, beam-to-column corner joints can not on- ly strongly affect the global structural behaviour of a frame, but also be a cause of its collapse. In the paper a component-based f.e. model of external beam-to-column joints is presented. The joint deformation is mod- elled by means of two unrelated contributions, the shear deformation of the panel zone, and the rotation at the interface sections between the joint and the structural members, due to the reinforcing bars’slip within the joint core. The first part of this work focuses on the evaluation of the joint strength and stiffness. Finally, the component-based f.e. model is validated by experimental results of tests on beam-column corner joint realized according the construction practice of the 60’s-70’s, confirming the effectiveness of the presented model for the assessment of existing structures.