Real-time hybrid simulation testing of novel sma-based seismic upgrade of precast concrete beam-to-column joints

Abstract

This paper presents real-time hybrid simulation (RTHS) experimental testing of a new upgrade system for seismically deficient precast buildings using shape memory alloy (SMA). The system, called SMA partial moment transfer (SMA-PMT) is installed strategically at beam-to-column joints within the precast building to develop a frame system (up to the capacity of the existing column and beam at joint) acting along the existing building shear wall to resist lateral loads, as opposed to upgrading the seismic capacity by strengthening the existing shear wall which is often challenging from a constructability perspective. Three beam-to-column joints equipped with SMA-PMT devices were subjected to six RTHS tests using scaled earthquake records. Results indicate that the SMA-PMT devices successfully establish partial frame action at targeted joints, significantly improving lateral load capacity and seismic performance while limiting residual deformations. The findings experimentally validate the previously proposed retrofit concept and demonstrate the potential of SMA-based devices for upgrading deficient lateral systems in existing precast buildings, providing a practical solution for seismic risk mitigation.