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根据极限状态设计法及可靠度分析的要求,本文从风荷载入手,建立在设计基准期内最大值分布的概率模型,取代过去习用的多年一遇设计风速值。此模型考虑了各有关风荷载计算系数在自然界中的变异性,论证了大气容重,风载高度变化系数、体形系数等均可视为随机变量。同时根据各地域长期风速序列平均值大小各异的特点,采用风载因子——(V/■)~2作为计算风荷载的笫二个随机变量。以两随机变量乘积之概率分布的形式推导出一个对于海岸工程建筑物具有普遍性意义的风荷载概率模型。此模型可以进一步与波、流等其它形式的环境荷载组合,建设综合概率模型。这是极限状态设计法和可靠度分析中不可缺少的重要内容。
According to the requirements of the limit state design method and the reliability analysis, this paper starts with the wind load and establishes the probability model of the maximum value distribution in the design reference period, replacing the conventional design wind velocity value in many years. The model takes into account the variability of the relevant wind load calculation coefficients in nature. It is demonstrated that the bulk density, the wind load altitude variation coefficient and the body shape coefficient can all be regarded as random variables. At the same time, wind load factor - (V / ■) ~ 2 is taken as the second random variable to calculate the wind load according to the characteristics of the mean value of the long-term wind speed series in different regions. Based on the probability distribution of the product of two random variables, a wind load probability model with universality significance for coastal engineering buildings is derived. This model can be further combined with other forms of environmental loads such as waves and currents to build a comprehensive probabilistic model. This is an indispensable and important part of the ultimate state design method and reliability analysis.