Experimental investigations on prefabricated interlocking prestressed tendon composite joint and its application to beam-column connection

This study proposes an interlocking prestressed tendon composite joint (I-PTCJ) that can be applied to a beam–column connection of the multi-story structure. First, the main structure and prefabrication process of the I-PTCJ were introduced. Next, three beam–column specimens using local and integral I-PTCJs (named specimens PT1 and PT2) and a traditional interlocking joint (I-J, specimen named TG1) were designed and manufactured. Furthermore, quasi-static experiments were performed on these three specimens to evaluate their seismic performance. In addition, the influence of the prestressed tendons (PTs) and the arrangement mode (local or integral) of the I-PTCJs were investigated in detail. Finally, a preliminary comparative analysis between the experimental and simulated results was carried out. The results showed that the introduction of the PTs reduced the degree of damage within the PT installation area, delayed the cracking of the interlocking interface, and improved the bond performance of the longitudinal rebar. However, it also aggravated the degree of damage outside the PT installation area and reduced the displacement ductility and energy dissipation capacity of the specimen. Compared with TG1 (using the traditional I-J), PT1 (using the local I-PTCJ) had a higher peak load, lower displacement ductility, higher shear deformation, gentler rigidity deterioration, and lower cumulative energy dissipation. Compared with PT1, PT2 (using the integral I-PTCJ) had a higher peak load, lower displacement ductility, lower shear deformation, lower cumulative energy dissipation, and better bond performance of the longitudinal rebar. Both the yield displacement angle and ultimate displacement angle met the deformability requirement of the existing building design codes. Thus, the proposed I-PTCJ can be applied to the beam-column connection of multi-story structures.