Seismic Vulnerability of Flat Plate Column Joint With Out Slab Shear Reinforcement

Abstract

During an earthquake, a brittle punching failure can arise in flat plate-column connections due to poor transfer capacity of shearing forces and unbalanced moments. To increase the shear capacity of the slab, various types of shear reinforcement can be used in the slab around the connection. The aim of the project is to study the response of slab column connections containing without slab shear reinforcement when subjected to combined gravity and cyclic lateral loading. At first a calibration model was developed to simulate the tested flat plate-column joint using finite element analysis program MASA. This model was used to predict the load displacement behaviour. The predicted behaviour was compared with the observed behaviour as reported by James Lee & Ian Robertson (Ref.4). The comparison showed that the model predicts the load level excellently but significantly over estimates the stiffness of the joint compared to that observed by James Lee & Ian Robertson. Since the present study is to compare the relative behaviour of slab-column joints provided without slab shear reinforcement, the error in the estimation of joint stiffness will not alter the comparative conclusions drawn. Thus, the developed model was validated for application to various types of column slab connection behaviour.