多车道荷载下组合梁斜拉桥疲劳性能分析

Fatigue Property of Composite Beam Cable-stayed Bridge Under Multi-lane Load

为了给大跨径钢-混组合梁斜拉桥抗疲劳设计提供依据,针对珠海某水道主航道桥,开展了多车道荷载下钢-混组合梁斜拉桥疲劳性能分析。首先建立全桥有限元模型,通过慢车道标准疲劳车移动荷载分析,获得最不利钢主梁、混凝土桥面板和斜拉索的具体位置。然后基于英国BS5400规范和Miner准则,考虑各车道的影响,获得了最不利钢主梁和斜拉索200万次等效疲劳应力幅以及混凝土桥面板的损伤度。结果表明:中跨455m处钢主梁和边跨ES3#斜拉索为疲劳关键部位,其运营期内200万次等效应力幅分别为61.03MPa和50.16MPa,均小于200万次疲劳破坏应力幅;塔梁结合处混凝土桥面板的疲劳损伤度为5.27×10-8,远小于1,均满足设计要求。研究成果对大跨径钢-混组合梁抗疲劳设计具有直接的指导作用。

To provide a reference for anti-fatigue design of long span composite beam cable-stayed bridge, aimed at a main channel bridge in Zhuhai city, fatigue property analysis of long-span composite beam cable-stayed bridge was carried out. Firstly, a finite element model of whole bridge was established to obtain the most unfavorable steel girder, concrete deck and stayed-cable by moving load analysis when the standard fatigue vehicle applied on the slow lane. Then, based on BS5400 specification and Miner criterion, the two-million equivalent stress amplitude of the most unfavorable steel girder and stayed-cable were obtained considering the multi-lane load, as well as the fatigue damage degree of concrete deck. The results show that the steel girder 455 m away from the beginning and the ES3 ~ stayed-cable located at side-span is the most unfavorable steel girder and stayed-cable respectively, and the two-million equivalent stress amplitude of which reaches to 61.03 MPa and 50.16 MPa separately, less than the fatigue strength stipulated in design specification. And the fatigue damage degree of concrete deck located at the junction between tower and beam is 5.27- 10^-8 , far less than 1. The research results have guiding function to anti-fatigue design of long-span composite beam cable-stayed bridge.