预应力混凝土梁疲劳性能研究现状

摘要

对预应力混凝土梁疲劳性能的研究进展进行了详细阐述,论述了等幅疲劳荷载下预应力混凝土梁的疲劳性能及疲劳加载后的静力性能,对控制其疲劳破坏形态的影响因素以及在疲劳加载过程中的受力筋应变变化、裂缝开展和挠度变化规律进行了总结.讨论了变幅疲劳荷载下预应力混凝土梁的疲劳寿命及加载顺序对疲劳寿命的影响,分析了变幅疲劳加载过程中的刚度退化,同时对腐蚀后预应力混凝土梁的疲劳性能进行分析,总结了钢绞线、普通钢筋腐蚀损伤对试验梁疲劳破坏形态、极限承载力及疲劳寿命的影响.在对文献进行总结分析的基础上,根据当前研究所存在的问题,提出了今后预应力混凝土结构疲劳性能研究的方向.结果表明:预应力混凝土梁疲劳破坏始于受力筋疲劳断裂,受压区混凝土一般不会发生破坏,变幅疲劳加载及腐蚀损伤对其疲劳性能有较大影响.%The research progress of fatigue performance of prestressed concrete beams was summarized in detail.The fatigue performance under constant-amplitude fatigue loading and static behavior after fatigue loading of prestressed concrete beams were discussed.The influence factors controlling the fatigue failure pattern, the strain variation of forced steel bars, the development of cracks and the variation of deflection during fatigue loading were summarized.The fatigue life of prestressed concrete beams under variable-amplitude fatigue loading and the influences of loading sequence on fatigue life were discussed, and the stiffness degradation in the process of variable-amplitude fatigue loading was analyzed.The fatigue performance of corroded prestressed concrete beam was analyzed.The influences of corrosion damage of steel strand and common steel bar on the fatigue failure pattern, ultimate bearing capacity and fatigue life of the test beam were summarized.Based on the summary and analysis of the literatures, the research direction of fatigue performance of prestressed concrete structures was put forward considering the existing problems of the current research.The results show that the fatigue failure of prestressed concrete beams starts with the fatigue fracture of the tendons, and the concrete in compression zone generally does not break.Variable-amplitude fatigue loading and corrosion damage have great influence on fatigue performance.