Experimental study on seismic behavior of prestressed concrete flat beam frame joints
LIU Qingwen;WANG Fangbin;School of Civil Engineering and Architecture,Nanchang Hangkong University;
The seismic behavior of four prestressed concrete flat beam frame exterior joints are studied under low frequency reversed loading. The failure features,characteristic loads,hysteresis loops,skeleton curves,ductility and energy dissipation of exterior joints are analyzed under seismic loads. Studies show that the first crack appears in the vicinity of beam-column,and the final failure occurs mainly in the joint outer region. The load-displacement hysteresis loops of joints are plump,and the displacement ductility coefficient is between 3. 7 and 5. 13,which reflect that joints have good ductility and energy dissipation capacity. The change of ductility and energy dissipation capacity is not obvious with the number of prestressing tendons through the outer joint core area. The failure pattern of specimens is bond slip mechanism of the interface between rebars and concrete in the joint outer region,while the joint inner core area does not reach the ultimate strength of stirrups. It is recommended flat beam frame joints should be set vertical stirrups in the joint outer region. We can conclude that prestressed concrete flat beam-column joints have good seismic perfomance,and can be applied to the seismic structure by reasonable construction measures.