Experimental study of a novel prestressed precast concrete beam-to-column joint based on plastic hinge relocation

Abstract

To avoid the difficulties and high costs associated with traditional prestressed dry joints in construction, a novel post-tensioned precast concrete frame based on plastic hinge relocation (PPFBP) beam-to-column joint is proposed in this study. The precast columns and beams were integrated solely through the application of post-tensioned (PT) strands. The combined use of the haunched beams and the vertical slots for plastic hinge relocation simplifies the connection of the joint and enhances assembly efficiency. The mechanism of the proposed joint is analyzed first, followed by the development of a complete design procedure that complies with the criteria for plastic hinge relocation and self-centering. Three full-scale interior beam-to-column joints were designed and tested under cyclic loading to investigate the seismic performance in hysteresis curves, ductility, energy dissipation capacity, and residual displacement. The results indicate that the bearing capacity and ductility of the proposed joint are similar to those of cast-in-place structures, with the advantage of minimal residual displacement, enabling rapid post-earthquake repairability. The hysteresis curve of PPFBP joint with plastic hinge relocation exhibits a flag shape, indicating significant self-centering capability and energy dissipation ability. The cumulative energy dissipation of PPFBP joint with plastic hinge relocation is much higher compared to that without it, achieving a maximum equivalent viscous damping coefficient of about 15 %, which is similar to that of hybrid dry joints. The insufficient strength of the prestressed grouting material led to bond slippage in the specimen with bonded PT strands, exhibiting a hysteresis response similar to that with partially bonded PT strands. Finally, the prediction of the bearing capacity in PPFBP joint is consistent with the experimental results, validating the effectiveness of the proposed design method.