以实际工程中的10方立式钢储罐为研究对象,采用刚性缩尺模型风洞试验方法,获得大型低矮圆柱结构内外表面的风压分布规律.结果表明:大型低矮圆柱壳结构外表面的风荷载与规范采用的数据有较大差异,内表面风压呈现出明显的波动.对平均风压和脉动风压的相关性分析表明,准定常理论仅对外表面的背风区适用.对各测点风压时程数据进行三阶和四阶矩统计量分析,研究低矮圆柱壳表面风压的非高斯特性.结果显示:绝大多数测点的概率密度偏离高斯概型.为了便于设计应用,给出非高斯峰值因子的参考数值.与以往试验结果的比较表明:不同高径比的圆柱壳风荷载有所不同,负压区的体型系数绝对值随着高径比的增大而增大.
Taking typical steel tanks in practice with volume of 100 000 m3 as research object, wind tunnel test on rigid scale models was carried out to obtain wind pressure distributions on both internal and external walls for large cylindrical structures with very low aspect ratio. It is shown that, wind pressures outside cylindrical wall exist obvious difference with those provided in related specifications, and wind pressures inside cylindrical wall fluctuate markedly. Results from correlation analysis of mean and fluctuating pressures indicate that, quasi-steady theory is only applicable to the windward region of external wall. The third and fourth moments of wind pressure time history data were calculated to investigate the non-Gaussian feature of wind pressures on large cylindrical structures. It is shown that the probability distribution of fluctuating wind pressure for most taps deviates from Gaussian distribution. The peak factors for estima- ting the maximum positive and negative wind pressures are given for ease of application in design. Comparison with earlier test results indicates that, wind loads on cylindrical structures vary with the aspect ratio, and the maximum negative mean pressure coefficient increases with the increase of the aspect ratio.