Reinforced concrete beam-column joints strengthened in shear with embedded bars

Beam-column (BC) joints play an important role in the seismic performance of moment-resisting reinforced concrete (RC) frame structures. Without adequate joint shear reinforcement, BC joints can be the most vulnerable elements during an earthquake. Several techniques for improving the seismic performance of BC joints have been proposed, but they have been criticised for being labour-intensive and/or susceptible to premature debonding. This research explores the application of the deep embedment technique for strengthening a shear-deficient beam-column joint. Two approaches, experimental and finite element (FE) study were conducted. The experiment contained the tests of seven exterior RC BC joints under constant column axial load and a reverse cyclic load at the beam end. Variables considered during the experiments were the material type and embedded reinforcement ratio. The FE study included the modelling of the tested specimens using ABAQUS and parametric study to asses the effect of column axial load, concrete compressive strength and embedded bar size on joint shear strength. The experimental results showed the strengthened specimens had superior global and local behaviour compared to the control one. In addition, the maximum joint shear strength also changes linearly with the variation of the concrete strength, column axial load and embedded bar size