大跨度悬索桥抖振的概率疲劳累积损伤分析

为探讨脉动风作用下大跨度悬索桥的抖振疲劳问题，在桥梁抖振时域分析基础上，得到悬索桥构件的应力响应时程。采用雨流计数法对不同等级风速作用下的应力循环进行统计，同时假设构件疲劳寿命服从威布尔分布，得到风振的疲劳累积损伤及可靠度分析方法。最后以东海某大跨悬索桥为对象进行了详细探讨。结果表明：该桥的主缆及吊杆在脉动风荷载作用下有足够的疲劳可靠度，不会出现疲劳破坏；加劲梁在高风速下抖振疲劳损伤较大，在运营过程中，应加强对加劲梁在强风作用后的损伤检测。

In order to study the buffeting fatigue of large-span suspension bridge under action of fluctuating wind,this paper concludes the stress response time of bridge members by analyzing the time domain of the buffeting. And the rainflow-counting algorithm is adopted to record the stress cycles at different wind speeds. At the same time,accumulated fatigue damage and reliable analysis methods arrive upon the assumption that the distribution of members' fatigue life matches Weibull shape. This paper uses a large-span suspension bridge at the East China Sea as study object and detailed analysis shows that under fluctuating wind load,the main cables and the suspenders demonstrate sufficient fatigue reliability; therefore fatigue damage will not occur in its operation. However,stiffening beams bear major damage at high wind speed,hence damage examine is require.