荆岳长江大桥附近大风特征及设计风速推算研究

Study on the Estimation of Designed Wind Speed for Jingyue Yangtze River Highway Bridge

利用岳阳气象站1952-2000年逐年10min平均最大风速资料序列，对大风特征进行了分析．利用极值Ⅰ型分布曲线，推算出气象站处基本风速，结合沿江观测对比记录，通过比值法把基本风速推算到设计风速．结果表明：（1）桥位附近10min平均年最大风速极值24．7m／s，主导风为东北风；（2）不同重现期（100，50，30，10a）10m高处10min平均年最大风速（基本风速）分别为27．6，25．4，23．8，20．2m／s；（3）考虑5％的计算误差，桥位区不同重现期（100，50，30，10a）10m高处10min平均年最大风速（设计风速）分别为29．0，26．7，25．0，21．2m／s；（4）利用近地层风速随高度的指数变化推算出300m以下每10m高度层的设计基准风速．

Using the yearly series of maximum 10 min averaged wind velocity observed by Yuyang weather stations from 1952 to 2000, the gale characteristics of Yuyang weather stations was analyzed. The reference wind velocity and design wind velocity were calculated by adopting the function of Extreme Ⅰ and referencing the observed wind datum along Yangtze River nearby bridge location. Several conclusions are listed as following. （1） the bridge location takes EN wind as dominant wind direction and extreme value of maxinum 10 min wind velocity is 24.7 m/s. （2） The annually averaged maxi- mum 10 rain wind velocity of the 10 meter high for different return periods（100, 50, 30,10 year） are respectively 27.6 m/s,25.4 m/s,23.8 m/s and 20.2 m/s. （3） the averaged maximum 10 rain wind ve- locity of the 10 meter high of bridge location for different return periods（100, 50, 30,10 year） are re- spectively 29.0 m/s,26.7 m/s,25.0 m/s and 21.2 m/s. Finally, the design reference wind speed of every 10 m layer within 300 m high is extrapolated by using the index change of wind velocity in the surface layer changed by the height, which can be referred for design and construction of the bridge.