基于直接概率积分法的重载铁路RC梁疲劳可靠度分析  

Fatigue reliability analysis of RC beams in heavy-haul railways based on direct probability integral method

作　　者：高天骁 李铸珅 张佳旺 宋力[2,3] 崔晨星 余志武 GAO Tianxiao;LI Zhushen;ZHANG Jiawang;SONG Li;CUI Chenxing;YU Zhiwu(Shuohuang Railway Development Co.,Ltd.,Suning 062350,China;School of Civil Engineering,Central South University,Changsha 410075,China;National Engineering Research Center of High-speed Railway Construction Technology,Changsha 410075,China)

机构地区：[1]国能朔黄铁路发展有限责任公司,河北肃宁062350 [2]中南大学土木工程学院,湖南长沙410075 [3]高速铁路建造技术国家工程研究中心,湖南长沙410075

出　　处：《铁道科学与工程学报》2023年第4期1416-1424,共9页Journal of Railway Science and Engineering

基　　金：朔黄铁路发展有限责任公司资助项目(SHGF-18-50);国家“863”计划资助项目(2007AA11Z180)。

摘　　要：既有重载铁路线路运营列车轴重提高会造成钢筋混凝土(RC)梁产生更加严重的疲劳问题,影响桥梁的服役性能。为研究重载铁路RC梁的疲劳可靠度,从概率的角度保障重载铁路桥梁的服役安全,根据重载铁路的运营特点,建立重载铁路RC梁的疲劳功能函数,提出基于直接概率积分法的重载铁路桥梁结构的疲劳可靠度分析方法。以某既有重载铁路跨度为8 m的RC简支板梁为例,分析该重载铁路的不同轴重货运列车的荷载模型,将列车轴重与动力系数作为随机变量,并通过移动荷载法与雨流计数法获取钢筋等效应力幅的概率模型。在此基础之上,结合重载铁路的等效运营谱,对跨度为8 m的RC板梁进行疲劳可靠度评估,并探讨年运量及列车轴重对疲劳可靠度的影响。研究结果表明:直接概率积分法能够高效精确地对重载铁路RC梁进行疲劳可靠度评估。在该重载铁路运营的前20年,疲劳失效概率均小于规范规定的限值。随着重载铁路年运量的提高,RC板梁的疲劳失效概率显著增大。运营列车轴重从23 t增大至25 t对RC板梁的疲劳可靠度影响较小。开行30 t轴重列车会造成RC板梁的疲劳可靠度严重下降,需要加强重载铁路桥梁的养护维修。研究结果可为重载铁路RC桥梁的设计与养护维修提供依据。The increase in axle load of operating trains on existing heavy-haul railway lines leads to more serious fatigue problems of reinforced concrete(RC)beams,which seriously affects the service performance of bridges.The objective of this researchwas to study the fatigue reliability of RC beams in heavy-haul railways and to ensure the service safety of heavy-haul railway bridges from the perspective of probability.According to the operation characteristics of heavy-haul railways,the fatigue performance function of RC beams in heavy-haul railways was established,and the fatigue reliability analysis method of heavy-haul railway bridges was proposedbased on the direct probability integral method(DPIM).By taking an 8 m-span simply supportedRC plate beam of an existing heavy-haul railway as an example,the load models of freight trains with different axle loads of the heavy-haul railway were analyzed.The train axle weight and dynamic coefficient were taken as random variables,and the probability model of reinforcement equivalent stress range was obtained through the moving load method and rain flow counting method.On this basis,combined with the equivalent operation spectrum of heavy-haul railway,the fatigue reliability of the 8 m-span RC plate beam was evaluated,and the effects of annual traffic volume and train axle weight on fatigue reliability were discussed.The results indicate that the DPIM can evaluate the fatigue reliability of RC beams in heavy-haul railways efficiently and accurately.In the first 20 years of operation of this heavy-haul railway line,the fatigue failure probability is lower than the limit specified in the design code.With the increase in the annual traffic volume of the heavy-haul railway,the fatigue failure probability of the RC plate beam increases significantly.The increase of train axle weight from 23 t to 25 t has a slight effect on the fatigue reliability of RC plate beams.The operation of 30 t axle weight trains wouldseriously reduce the fatigue reliability of RC beams,so it is necessary to

关 键 词：重载铁路 钢筋混凝土梁 直接概率积分法 等效应力幅 疲劳可靠度 失效概率 

分 类 号：TU375.1[建筑科学—结构工程] U24[交通运输工程—道路与铁道工程]