为满足大深宽比高层建筑抗风设计要求,通过同步测压试验研究B类和C类地貌下深宽比1/8～8.0范围内矩形建筑的横风向基底弯矩谱.通过矩形断面气动力分布研究侧面分离再附流动特性,并根据流动特性分析横风向风压谱的能量分布与转化特征.研究结果表明:当深宽比超过3.0时,侧风面分离流发生稳定再附,沿流向风压系数均值和标准差均表现出先增大后减小的特征,随湍流度增大,再附位置向上游移动;横风向基底弯矩谱呈现显著的尖峰特征,当深宽比超过3.0时,由于分离流再附进而出现第二谱峰;当深宽比小于1/3时,横风向基底弯矩谱高频能量较大;提出横风向基底弯矩系数标准差、斯特劳哈尔数以及归一化基底弯矩功率谱在深宽比1/8～8范围内的拟合公式;获得横风向风振计算的求解公式,在合理约化频率范围内,基于拟合公式计算的风振响应和等效风荷载结果比GB 50009-2012《建筑结构荷载规范》和AU 2004《AIJ recommendations for loads on buildings》中相关公式计算结果更加接近试验值,且深宽比的适用范围更大.
Crosswind base bending moment spectral model for rectangular high-rise buildings with large side ratios
In order to satisfy the wind-resistant design requirements for high-rise buildings with large side ratio,the crosswind base bending moment spectrums of rectangular buildings with side ratio of 1/8～8.0 in terrain categories B and C were investigated by means of synchronous pressure measurement tests in this study.The characteristics of lateral separation and reattachment flow through rectangular cross-section aerodynamic distribution were studied,and the energy distribution and transformation characteristics of the crosswind wind pressure spectrum were analyzed based on the flow characteristics.Results show that stable reattachment would occur when the side ratio was greater than 3.0,and both the mean and standard deviation of wind pressure show characteristics of first increasing and then decreasing along the flow direction,and the attachment position moves upstream as the turbulence intensity increases.The crosswind wind pressure spectrum exhibits significant peak characteristics.When the side ratio exceeds 3.0,a second spectral peak emerges as a result of the reattachment of the separated flow.And when the side ratio is less than 1/3,the high-frequency energy is significantly higher.Fitting formulas for the standard deviation of the crosswind base moment coefficient,Strouhal number,and the normalized base moment spectrum within the side ratio range of 1/8～8 were proposed.The solution formula for crosswind vibration calculation was obtained.The wind-induced response and equivalent static wind load calculated based on fitting formulas are closer to the test values than the results calculated by relevant formulas in the standard GB 50009-2012'Load code for the design of building structures'and AIJ 2004'AIJ recommendations for loading on buildings',with a wider applicability range of side ratio.
rectangular buildingcrosswind directionside ratiobase moment spectrumseparation reattachment
万方数据
维普
