武汉二七长江三塔结合梁斜拉桥疲劳特性分析

利用大型有限元软件Midas/Civil建立武汉二七长江大桥全桥三维有限元模型.根据成桥阶段内力计算,确定了主跨跨中截面、主跨1/4跨截面、边跨混凝土主梁结合段、中塔最外侧斜拉索和边塔最内侧斜拉索作为疲劳破坏最危险部位.选取英国规范BS5400、美国规范AASHTO、欧洲规范Eurocode1和我国的6轴标准疲劳车,分别对疲劳破坏最危险部位进行加载计算,获得了运营期内各最危险部位的疲劳应力谱.结合武汉二七长江大桥的设计交通流量,计算得到了疲劳车辆年平均日交通流量.选取不同材料的疲劳S-N曲线,利用疲劳累积损伤准则计算得到了最危险部位的年累计损伤度.比较四种标准疲劳车在疲劳寿命评估中的准确性,最后综合评估武汉二七长江大桥的疲劳性能.结果表明,该桥100年运营期内不会发生疲劳破坏.

Fatigue Behavior Analysis of Wuhan Erqi Yangtze River Composite Girder Cable-stayed Bridge with Three-tower

Using the large general software Midas/Civil to establish full bridge dimensional finite element model of Wuhan Erqi Yangtze River Bridge.According to the internal force calculation on the formation bridge stage,the cross-section of the main span、the 1/4cross-section of the main span、the concrete main beam joint section of the side span、the outermost cable-stayed of the middle tower and the innermost cable-stayed of the side tower were determined as the most dangerous part of the fatigue damage.Selecting the standard fatigue vehicle of British norms BS5400、U.S.norms AASHTO、European norms Eurocode1 and document 4,loading calculation for the most dangerous fatigue damage parts is done to obtain the fatigue stress spectrum of the various most dangerous parts during the operations.Combining the design traffic flow of Wuhan Erqi Yangtze River Bridge,the annual average daily traffic flow of fatigue vehicles is calculated and obtained.Selecting different materials＇ fatigue SNcurve,the annual cumulative injury degree of the most dangerous part with the fatigue cumulative injury criteria is calculated and obtained,comparison of the accuracy of four standard fatigue vehicle fatigue life evaluation.Compared with the accuracy of fatigue life evaluation of four kinds of standard fatigue vehicles,it can evaluate the fatigue performance of Wuhan Erqi Yangtze River Bridge comprehensively.The results show that：fatigue damage will not occur during the 100-year operations,which could provide a theoretical reference for the bridge fatigue safety during the operations.