摘要:研究目的:HRB500钢筋是桥上纵连板式无砟轨道中的主要受力钢筋，其在服役期间的疲劳特性是工程 界十分关注的问题。为研究桥上纵连板式无砟轨道HRB500钢筋的疲劳性能，本文首先进行HRB500钢筋的 静力拉伸试验，在此基础上，对7种不同应力水平下HRB500钢筋进行对称拉压循环荷载下等幅疲劳试验。研究结论:( 1)根据试验结果拟合得到了 HRB500钢筋的S- N曲线；（2)依据相关规范对铁路工程结构 物可靠度指标和纵向连接钢筋疲劳强度折减系数的相关规定，并参考英国BS 5400规范关于钢筋长寿命区S- N曲线的外推方法和由中值S- N曲线推导不同概率S - N曲线的相关规定，得到了可靠度指标4. 2的适 用于桥上纵连板式无砟轨道钢筋疲劳寿命预测的HRB500钢筋S- N曲线；（3)本研究成果可以为桥上纵连 板式无砟轨道HRB500钢筋疲劳寿命预测模型的建立提供试验依据。

Abstract ： Research purposes ： HRB500 steel bar is the main load - bearing steel bar in longitudinal connected slab track on bridge， and its fatigue properties during service life have received great attention in engineering circles. In order to study the fatigue properties of the HRB500 steel bar in longitudinal connected slab track on bridge， static tension tests on the mechanical properties of HRB500 steel bar were conducted first. On the basis of static tests， constant amplitude fatigue tests on HRB500 steel bar under fi^lly reversed tension and compression cyclic load for seven different kinds of stress levels were conducted. Research conclusions：( 1) The S - V curve of the HRB500 steel bar was fitted according to the fatigue test results； According to the codes in related standards on the reliability indication of railway engineering structures and fatigue strength reduction coefficient of longitudinal connected steel bar， as well as considering the relevant codes in Britain standard 5 400 on the extrapolation method of the long - life S - V curve of steel bar and on deducing S - V curves with different probabilities using middle value S - V curve，the S - V curve of HRB500 steel bar with reliability index of 4. 2 which is suitable for the fatigue life prediction of HRB500 steel bar in longitudinal connected slab track on bridge was deduced; (3) The research results can provide experimental basis for the establishment of life prediction model of HRB500 steel bar in longitudinal connected slab track on bridge.