Experimental study on two innovative ductile moment-resisting precast concrete beam-column connections

The use of precast concrete elements in construction leads to increased output quality, better product control, cost savings, and reduced construction time. The main problem of precast concrete structures is the improper performance of connections under lateral loads. In the present study, the aim is to improve the behavior of precast connections under cyclic loading. Two new beam-column precast connections with steel profiles as corbel with high-strength bolt fasteners are developed. Those connections have been designed to be used in intermediate moment frames in regions with high seismic risk. The advantage of these connections is the elimination of the need for remarkable concrete formwork, temporary supports, and low demand for in-situ concrete during construction and providing the possibility of construction progress on the floors in parallel. For studying the seismic performance of proposed connections, six specimens including four precast and two monolithic connections with different rebar ratios were made. The specimens were subjected to a horizontal displacement control cyclic loading to obtain the load-displacement curves. The maximum lateral strength, ductility, strength degradation, stiffness reduction, and energy dissipation of precast connections were evaluated and compared with the in-situ connections. The ultimate strength and ductility of the precast connections were similar to the in-situ specimens, and proposed connections showed good cyclic behavior. The strength degradation and stiffness deterioration of precast connections were more than the in-situ connection, and the energy dissipation of them was less than monolithic connections. According to the analysis results, the performance of the proposed connections is acceptable and satisfies the criteria of the connections for use in areas with high seismicity.