Quasi-static Test Research on Seismic Behavior of Monolithic Precast UHPC-NC Composite Frame

The seismic performance of monolithic precast Ultra-High Performance Concrete (UHPC)-Normal Concrete (NC) composite frame was evaluated using quasi-static tests on two 1/2 scaled three-story, two-span frames. The frames included one fully cast-in-place reinforced concrete frame (RCF) and one monolithic precast UHPC-NC composite conctete frame (PCF). The UHPC-NC composite frame consisted of precast columns, composite beams constructed with a precast U-shaped UHPC beam shell and a post-cast NC beam core, and beam-column joints made of post-cast UHPC. The results show that:the damage process of both frames is essentially the same, but the PCF has less damage and better integrity compared to the RCF. The hysteresis curves of both frames are plump. The load-carrying capacity of the PCF is enhanced by 16% compared to that of the RCF. The PCF has a higher energy dissipation capacity than the RCF. The stiffness of the PCF is slightly higher and degrades slower than that of the RCF. The displacement ductility coefficients range from 3.9 to 4.6 for both frames, with the PCF having slightly higher ductility coefficients than the RCF. The seismic performance of the monolithic precast UHPC-NC composite frame structure is superior to that of the fully cast-in-place frame structure.