Seismic performance evaluation of reinforced concrete beam-column joints of existing buildings

Common computer programs generally model beam-column joint (BCJ) as a finite point without physical property that will neither yield nor fail. However, this assumption is not appropriate for modelling existing buildings without seismic provisions where the shear capacities of BCJs were uncertain. This paper presented the finite element analysis and cyclic load test results of four full-scale edge column BCJ specimens with and without column and BCJ shear link detailing according to seismic provisions. The aim was to compare the numerical analysis and experimental results to establish a reduction factor between BCJ with and without seismic detailing provisions and to verify the accuracy of numerical analysis results. With the proposed reduction factor, non-seismic provisioned BCJ that will fail under seismic actions can be determined from general computer analysis programs and correspondingly strengthened if necessary to ensure that yielding occurs in structural members connected to the joint instead of brittle joint shear failure. Furthermore, splitting crack along the lower column axis was observed in all non-seismic provisioned specimens due to eccentricity between the upper and lower column load centre and inadequate link confinement in the lower column.