Abstract
The previous research on the precast beam column butt joints showed that prestresses induced by the thru bolts caused undesirable compressive failure at the joint blocks of precast beams and the system had poor seismic performances consequently. To prevent the compressive failure mode occurred, the remedial measures such as rectangular spiral hoops, steel end plates and Dog-boned tension steel bars are developed and provided at the joint blocks of precast beams. Those treatments are expected to increase compressive strength of the concrete, improve the anchorage of reinforcing bars and control the yielding location of steel bars respectively. Five types of specimen are designed by using one or two of the measures. Seismic performances are experimentally tested and effects of the measures are analysed. Test results show that the butt type precast beam and column joints with steel end plates anchorage and Dog-boned tension steel bars satisfy most of the seismic performance criteria of ACI requirements such as strength degradation, stiffness degradation and energy dissipation capacity. And they are supposed to be used effectively for the joints of special moment frames in the strong seismic zone areas.