建筑结构风压与蓄滞洪区风速计算方法研究

Study on Calculation Method of Wind Pressure for Building Structures and Wind Speed in Flood Detention Area

设计风压与蓄滞洪期间设计风速分别是建筑结构荷载计算和蓄滞洪区风浪计算的重要输入参数。现行GB/T 50181—2018《洪泛区和蓄滞洪区建筑工程技术标准》在采用基本风压计算蓄滞洪期间设计风速计算方法中没有考虑GB 50009—2012《建筑结构荷载规范》基本风压的重现期已提高为50 a的事实。通过对随机变量实施函数变换后的概率分布是否仍服从原分布的理论证明,得出若假定年最大风速服从极值Ⅰ型分布,则相应风压不服从该分布的结论,并予以实例验证,从而认为《规范》中不同重现期风压换算公式是不严谨的。基于伯努利方程、对数函数的Taylor展开等导出重现期风压的插值计算公式;针对我国蓄滞洪区分布区域,基于《规范》给出的10 a、50 a以及100 a三种重现期设计风压值,推算出我国各流域蓄滞洪区最大风速变异系数,进一步导出蓄滞洪期间设计风速与基本风压的计算关系。

The designed wind pressure and designed wind speed during flood detention are important input parameters for the load calculation of building structure and wind wave calculation of detention basin respectively.There are defects in the current wind pressure conversion method in“Load code for the design of building structures”GB 50009—2012,and the current“Technical standard for buildings in flood plains and flood detention areas”GB/T 50181—2018 fails to take into account that the reference wind pressure return period of GB 50009—2012 has been increased to 50 a in the calculation method of design wind speed during flood detention period.By proving whether the probability distribution of random variable still obeys the original distribution after the function transformation,the result shows that if annual maximum wind speed obeys Gumbel distribution,then the corresponding wind pressure don’t obey the distribution,which is verified by an example.Therefore,it is considered that the conversion formula of wind pressure at different recurrence stages in GB 50009—2012 is not rigorous.Based on the Bernoulli’s equation and Taylor series expansion of the logarithm function,the interpolation formula for calculating the wind pressure of different recurrence period is derived.Using the wind pressure values with recurrence period of 10 a,50 a and 100 a given by GB 50009—2012,the maximum variation coefficient of wind speed in flood detention areas of each river basin in China was calculated,and the calculation relationship between design wind speed and reference wind pressure during flood detention period was further derived.