Nonlinear finite element analysis of post-tensioned precast prestressed slab-beam-column joints

A new kind of Precast Prestressed Efficiently Fabricated Frame (PPEFF) system known as the PPEFF system has been used in China for several years, however there are few reports in English. Based on the hybrid frame system, the PPEFF system adds a post-cast composite layer on the top of the precast beam-slab and eliminates the energy dissipation rebars at the lower part of the beam-column joint. This makes it easier to compose a two-way moment-resisting frame without reinforcement congestion in the joint and simplifies the construction of the slab-beam-column joint. This paper introduces the PPEFF system and establishes a nonlinear finite element model that can accurately simulate the seismic performance of the PPEFF joint under low cycle loading. The FEM can simulate the opening and closing of the contact surfaces among slabs, beams and columns, as well as plastic damage mechanism. Hysteresis curves of the PPEFF joint under every step of low cycle loading from the finite element analysis are compared with those from a previous PPEFF joint experiment, showing good agreement. The effects of slab, post-tensioned strands and energy dissipation rebars on the seismic performance of PPEFF joints are further analyzed in this paper. Based on the analysis, some suggestions for seismic design are given.