气候变化对大跨度悬索桥台风颤振可靠性的影响研究

TYPHOON-INDUCED FLUTTER RELIABILITY ANALYSIS OF LONG-SPAN SUSPENSION BRIDGES UNDER CLIMATE CHANGE

  • 摘要: 气候变化已经成为世界各国政府和非政府组织的共识,海平面温度升高将会增强以海面温度为主要能量来源的热带气旋的频度和强度,导致气候变化台风极端风速的增大。本文以我国东南沿海及长江下游受台风影响的主要城市的10座大跨度悬索桥为背景,分析了全桥气弹模型风洞试验方法确定的颤振临界风速的随机性,建立了考虑颤振临界风速随机性的概率分布模型;基于容许应力法、超越概率法和气候变化模型,提出了随机和时变的颤振检验风速概率分布模型;建立了悬索桥颤振可靠性分析和概率性评价的极限状态方程,提出了基于蒙特卡罗数值模拟方法的悬索桥颤振失效概率计算方法,分析计算了10座大跨度悬索桥的颤振失效概率和可靠指标及其气候变化的影响。分析结果表明,考虑气候变化台风影响的颤振失效概率减小1个~3个数量级,不同气候变化路径导致的颤振失效概率相差4倍~60倍。

     

    Abstract: Climate change has now achieved consensus among governments and non-governmental organizations worldwide. The elevation of temperatures in sea surface is projected to enhance the frequency and intensity of tropical cyclones, which predominantly derive their energy from sea surface temperatures, leading to an increase in extreme wind speeds of typhoons associated with climate change. In this study, ten long-span suspension bridges located in major cities along China's southeastern coast and in the lower reaches of the Yangtze River, which are notably impacted by typhoons, are introduced to analyze the randomness of the critical flutter wind speed determined through full-bridge aeroelastic wind tunnel tests. A probabilistic distribution model accounting for the randomness of the critical flutter wind speed is established. Based on the permissible stress method, proposed is the exceedance probability method and, a climate change model, a probabilistic distribution model for the flutter check wind speed that is stochastic and time-variant. Developed is a limit state function for flutter reliability analysis and the probabilistic assessment of suspension bridge. A method is introduced for calculating the flutter failure probability of suspension bridges, based on the Monte Carlo numerical simulation technique. The flutter failure probabilities and reliability indices of these ten long-span suspension bridges and their implications in the context of climate change are calculated and discussed. The study results indicate that considering the effects of typhoons due to climate change, the flutter failure probability decreases by 1 to 3 orders of magnitude; and that the flutter failure probability varies by 4 to 60 times depending on different climate change pathways.

     

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