Seismic performance analysis of the prestressed prefabricated concrete frame structure with mortise-tendon joints

In this paper, a novel assembled concrete frame structure (Prestressed Mortise and Tenon Frame, PMTF) was proposed. The PMTF utilizes a combination of prestressed and mortise-tenon connections. The core zone of the joints in the PMTF involves the upper column tenon, integrating the slab-beam connection zone, and incorporating the lower column cups to create a mortise-tenon connection, similar to those found in timber structures. To ensure reliable connection between each component of the core zone, the unbonded prestressing strands (UPS) were applied. The UPS serves to provide the restoring force and reduce the residual deformation at the same time. To further investigated its seismic performance, One-story, two-span finite element model (FEM) of the PMTF was established using the FEM software ABAQUS. Firstly, the damage process and modes of the PMTF were analyzed under two different horizontal loading conditions: monotonic and low-cycle reciprocating loading. Secondly, the parametric analysis of the PMTF was carried out with four parameters: axial compression ratio, prestressing tendon area and initial effective stress of the UPS, and contact friction coefficient of concrete interface. Finally, a restoring force model of the PMTF was proposed. The results showed that the PMTF exhibited the moderate energy dissipation capacity and relatively small residual deformation, with damaged localized primarily in the core zone of the joints. The axial compression ratio had a more significant effect on the hysteretic performance of PMTF compared to the other parameters. The suggested values for each parameter were as follows: axial compression ratio less than 0.3, initial effective stress less than 0.75 f pu , and friction coefficient between 0.6 and 0.7. The proposed restoring force model can effectively predict the hysteretic performance of the PMTF.