绿植对高层建筑风压非高斯特性影响分析

Influence of vegetations on non-Gaussian characteristics of wind pressure in high-rise buildings

摘要:

第四代建筑的阳台上覆盖了大量绿植,其气动外形发生明显改变,来流受到绿植的扰动使得建筑表面风压变化更复杂。为探究绿植对高层建筑风压非高斯特性的影响,通过刚性模型测压试验,对不同覆植面积下建筑外立面极值风压和标准化风压系数的概率分布进行分析,给出了非高斯风压的经验判断标准和分布特征,揭示了绿植对建筑外立面极值风压的影响规律。分析结果表明:绿植的存在改变了来流在建筑迎风面分离点位置,使得边缘测点由非高斯性转化为高斯性,侧风面风压均表现出非高斯性,受绿植影响较小；窄面上的极值风压受绿植影响较小,而布置在相对较宽外立面上的绿植对该区域流场影响更大,不同绿化率作用下极值风压降低作用更明显；绿植对建筑极值风压的降低作用随覆植面积的增加先增大后减小,覆植面积为13.5%时风荷载降低作用最大。研究结果可为类似结构抗风设计提供参考。

Abstract:

The balconies of fourth-generation buildings are covered with a large number of vegetations, resulting in a noticeable alteration of their aerodynamic profiles. The airflow is disturbed by the vegetation, leading to more complex variations in wind pressure on the building surfaces. To investigate the influence of vegetations on the non-Gaussian characteristics of wind pressure on high-rise buildings, rigid model pressure tests were conducted to analyze the probability distribution of extreme wind pressures and standardized wind pressure coefficients on the building facade under different coverage areas of vegetations. Empirical criteria and distribution characteristics for non-Gaussian wind pressures were provided, revealing the influence of vegetation on extreme wind pressures on the building facades. The results indicate that the presence of vegetations changes the separation point position of incoming flow on the windward side of the building, causing the edge measurement points to transform from non-Gaussian to Gaussian. Conversely, crosswind wind pressure shows non-Gaussian, which is less affected by vegetations. The extreme wind pressure on narrow surfaces is less affected by vegetations, while vegetations arranged on relatively wide facades have a greater impact on the flow field in the area. The reduction of extreme wind pressure is more significant under different vegetation coverage rates. Furthermore, the effectiveness of greenery in reducing extreme wind pressures initially increases with the coverage area, reaching its maximum reduction effect at a coverage of 13.5%. The results can provide reference for wind-resistant design of similar structures.