跨海桥梁受台风影响的风速概率模型分析

ANALYSIS OF WIND SPEED PROBABILITY MODEL OF SEA-CROSSING BRIDGE AFFECTED BY TYPHOONS

  • 摘要: 中国东部沿海地区常受台风侵扰,各台风不同的气旋结构和登陆位置使其对跨海桥梁结构的影响有较大差异。台风期间桥位处的风速概率模型是分析桥位风场特征、评估桥梁抗风能力重要依据。安装于跨海桥梁上的结构健康监测系统实时获取的风场监测数据为了解台风期间桥位风场特征和开展风速概率模型分析提供了数据基础。以影响西堠门大桥的三个典型台风为研究对象,结合桥位风场实时监测数据,采用贝叶斯方法对风速概率模型参数进行动态识别与持续更新,建立的风速概率分布时变模型能够呈现不同时刻的风速概率分布及其在台风全过程中的演变规律,并对三个台风的风速分布及其演变进行了对比分析。对于近侧的登陆风,桥址风场的风速分布具有较大波动性;而对于远端风场,台风影响半径范围内风速分布相对稳定,影响半径范围外则风速分布波动强烈。

     

    Abstract: Typhoons frequently wreak havoc on China's eastern coast. The influence of typhoons with different cyclone structures and landing locations on sea-crossing bridges is quite different. The wind speed probability model at the bridge site is critical for studying the wind field characteristics and for evaluating the wind resistance capability of the bridge. The real-time monitoring data of wind field during typhoon periods obtained by the structural health monitoring system installed on the sea-crossing bridge provides the data basis for studying the wind field characteristics of bridge site and the analysis of a wind speed probability model. Three typical typhoons which have affected Xihoumen Bridge were investigated. Combined with the real-time monitoring data of the wind field at the bridge site, the parameters of the wind speed probability model were dynamically identified and continually updated using the Bayesian method. A time-varying model of wind speed probability distribution was developed, which can depict the wind speed probability distribution at any given time and its progression through the whole typhoon life cycle. Three typhoons' wind speed distribution and evolution were compared. As for the landing typhoon close to the bridge, the wind speed distribution at the bridge site fluctuates. When the typhoon's center is far away from the bridge, the wind speed distribution is relatively stable within the influence radius of the typhoon, and fluctuates strongly outside the influence radius.

     

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