实际车载下的在役混凝土梁桥承载性能演化分析  

Evolution analysis of bearing capacity of existing concrete beam bridge under actual vehicle load

作　　者：陈水生[1] 赵辉 李锦华[1] 朱朝阳 CHEN Shuisheng;ZHAO Hui;LI Jinhua;ZHU Chaoyang(School of Civil Engineering and Architecture,East China Jiaotong University,Nanchang 330013,China)

机构地区：[1]华东交通大学土木建筑学院,江西南昌330013

出　　处：《中南大学学报（自然科学版）》2022年第10期4096-4105,共10页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(12062006,11962006)。

摘　　要：为了探究在役混凝土梁桥在未来服役时间的承载力失效概率演化规律,首先采用蒙特卡罗随机抽样的方法生成随机车流荷载;然后,综合考虑桥梁车致荷载效应的随机性和桥梁抗力退化的时变性,基于经典极值理论和结构可靠度原理,给出在役混凝土梁桥的承载性能演化分析方法和步骤;最后,以一座在役简支T梁桥为工程案例,分析其在实际车流荷载作用下的承载力失效概率。研究结果表明:随着桥梁服役时间的增加,桥梁抗力的均值和标准差逐渐减小,而桥梁车致荷载效应极值的均值增大,标准差减小;混凝土梁桥的承载力失效概率随着桥梁服役时间的增加而增大,直接承受车辆荷载作用的主梁承载力失效概率大于非直接承受车辆荷载作用的主梁承载力失效概率,整个桥梁系统的承载性能取决于承载力失效概率最大的主梁;桥梁承载性能受运营环境的影响较大,抗力低速退化的承载力失效概率是抗力不退化的5.6倍。为保证在役混凝土梁桥的运营安全,针对重型货车出现频率较高和恶劣使用环境的桥梁,建造时应该提高安全储备,管养时可以采取适当的政策进行干预。In order to explore the evolution law of bearing capacity failure probability of existing concrete beam bridge in future service time,the Monte Carlo random sampling method was used to generate the random traffic flow load firstly.Then,the randomness of vehicle-induced load effect and the time variability of bridge resistance degradation were comprehensively considered.Based on the classical extreme value theory and structural reliability principle,the evolution analysis method and steps of bearing capacity of existing concrete beam bridge were given.Finally,an existing simply supported T-beam bridge was taken as an engineering case and the failure probability of its bearing capacity under actual traffic load was analyzed.The results show that the mean value and standard deviation of bridge resistance gradually decrease with the increase of the service time of bridge,while the mean value of extreme value of vehicle-induced load effect increases,and the standard deviation decreases.The failure probability of bearing capacity increases with the increase of service time of the concrete beam bridge,and the main beam direct under the vehicle load is greater than that of the main beam not direct under the vehicle load.The bearing capacity of the whole bridge system depends on the main beam with the largest bearing capacity failure probability.The bearing capacity of bridge is greatly affected by the operating environment,and the failure probability of low-speed degradation resistance is 5.6 times higher than that of the non-degradation resistance.In order to ensure the operation safety of existing concrete beam bridge,for bridge with high frequency of heavy truck and harsh service environment,safety reserves should be improved during construction,and appropriate policies can be taken to intervene in management and maintenance.

关 键 词：性能演化 随机车流 经典极值 抗力退化 失效概率 

分 类 号：TB114.3[理学—概率论与数理统计]