既有铁路混凝土梁疲劳与承载力可靠性评估

ASSESSMENT OF FATIGUE AND LOAD-BEARING RELIABILITY OF EXISTING CONCRETE BEAM OF A RAIL WAY BRIDGE

将列车荷载视为随机过程，考虑既有铁路混凝土梁的抗力劣化，采用时变的可靠性计算方法对川黔线一座铁路混凝土梁剩余使用期内承载力失效概率进行了计算。顾及到铁路混凝土梁的钢筋疲劳，对该梁随时间变化的疲劳可靠性指标进行了计算。综合这两种失效模式对桥梁安全性的影响，对该梁的体系可靠性进行了评估，预测了该梁的剩余使用寿命，进而提出了整改措施。

Regarding the train load as a random process, considering the resistance deterioraion of the existing concrete beam , the time -dependent reliability formula is adopted to calculate the failure probability of the existing concrete beam of a bridge in Chuan-Qian Railway during its remain service life. In consideration of the fatigue effect of the existing concrete beam, the time-dependent frtigue reliability index is computed. Taking accoun of the effects of both load-bearing failure model and fatigue failure model ; the system reliability of these two models is evalated. Based on previous efforts, the remain service life of the beam is predicted. Moreover, some suggestions are given about how to deal with the beam under present condition.