EXPERIMENTAL STUDY ON SEISMIC BEHAVIOR OF PRESTRESSED HIGH-STRENGTH CONCRETE BEAMS

Seismic behavior of the prestressed high strength concrete beams was studied based on the low-cycle reversed load test of three prestressed concrete beams,for which the strength grade of the concrete,mild steel and prestressing strand were C80,HRBF500 and 1 860 MPa separately.The test results indicated that the main failure mode of the specimens was that the compression concrete at the top side crushed severely,while the tension reinforcing bars and prestressing strands were not broken; crushing of the high strength concrete was more sudden,inducing that strength decrease of the specimens was relatively rapid; the load-deflection hysteresis loops were fatter,and the specimens had enough energy dissipation capacity; The yielding and ultimate strength of the specimens increased with the reinforcing ratio,while the ductility factor was just the opposite; with the medium conversion reinforcing ratio,the test specimens had certain deformation capacity under reversed load; the prestressed high strength concrete beams had preferable displacement restoring capacity.Reducing the prestressed intensity was helpful to increase the energy dissipation capacity of the prestressed high strength concrete beams．