Displacement-based seismic retrofit design for non-ductile RC frame structures using local retrofit interventions at beam-column joints

Seismic retrofit design using local retrofit interventions is often done using piece-meal iterative approach, in which the local retrofit design and global structural response are derived from iterative numerical models. Adopting a displacement-based seismic retrofit approach and following capacity-design principles, the effects of local retrofit interventions’ can be correlated to the expected global deformation responses. Clearly acknowledging that displacement (or drift) is a better response parameter for structural and non-structural damage, a displacement-based methodology gives a more direct and rational seismic retrofit design. This paper will first introduce the concepts of displacement-based seismic retrofit. Then, the design procedure is illustrated for two local retrofit interventions for RC frames: a) selective beam-weakening retrofit, and b) posttensioning retrofit and fibre-reinforced polymer jacketing. The design procedure is then verified using non-linear time-history analysis on a case study building retrofitted using the two local interventions.