预应力高强混凝土梁抗震性能试验研究

对三根混凝土强度等级为C80,纵筋为1860级钢绞线和HRBF500级钢筋的预应力混凝土梁进行低周反复加载试验,在此基础上对其抗震性能进行分析和研究。结果表明,预应力高强混凝土梁的破坏状态为受压区混凝土压碎,受拉钢筋和钢绞线均未拉断;由于高强混凝土脆性较大的特点,试件在反复荷载作用下破坏较为突然,承载力退化较快;试件的滞回环较饱满,有一定的耗能能力;试件的屈服强度和极限强度随换算配筋率的增大而增加,延性系数则随换算配筋率的增大有所减小。试验所采用的中等配筋率的预应力高强混凝土梁,在低周反复荷载下有一定的变形能力;预应力高强混凝土梁有较好的变形恢复能力;较小的预应力强度比有利于提高预应力混凝土构件的耗能能力。

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 λ was helpful to increase the energy dissipation capacity of the prestressed high strength concrete beams.