针对预应力混凝土桥梁中钢绞线局部锈蚀造成疲劳性能退化问题，制作了 6 根预应力混凝土梁，对其中 4 根不同钢绞线锈断位置的试验梁进行电化学加速锈蚀试验、静力加载和疲劳加载试验，研究了钢绞线断裂后预 应力混凝土梁的疲劳性能退化机理和力学性能退化规律，分析了混凝土表面裂缝扩展、荷载?挠度关系及疲劳寿 命。研究结果表明：L/4 锈断位置处的试验梁刚度退化和裂缝扩展规律，与未锈蚀梁和端部锈蚀梁的差异明显； 不同锈断位置的预应力混凝土梁的静载和疲劳性能均有不同程度降低；当锈断位置处于梁端时，钢绞线与混凝土 形成二次锚固效应，对梁的刚度保证具有积极作用。
In order to investigate the fatigue property degradation characteristic of prestressed concrete beam with local corrosion-induced fracture of steel strand, a total of 6 prestressed concrete beams were designed and fabricated. Electrochemical accelerated corrosion was applied to 4 of them at different locations of steel strand rust failure, and static and fatigue loading tests were carried out. The fatigue degradation mechanism and mechanical degradation characteristic of prestressed concrete beams destabilized by breaking steel strand were studied, and the crack propagation, load-deflection relationship and fatigue life of concrete were analyzed. The results show that, the stiffness degradation and crack propagation characteristic of beam with breaking steel strand at the position of L/4 are obviously different from those of non-corroded beam and beam with breaking steel strand at the position of end. The static load and fatigue properties of prestressed concrete beams with breaking steel strand are reduced. When the corroded position is located at the end of beam, the secondary anchorage formed by steel strand and concrete can provide a positive effect on the stiffness of the beam.