基于节段模型试验的千米级摩天大楼行人风环境特性研究

INVESTIGATION ON CHARACTERISTICS OF THE PEDESTRIAN WIND ENVIRONMENT OF A THOUSAND-METER-SCALE MEGATALL BUILDING BASED ON SUB-CONFIGURATION EXPERIMENT

某千米级摩天大楼是由正三角形布置的外围3个泪滴型塔楼和中心1个圆形塔楼组成的巨型组合结构,沿其高度每隔100 m共设置10个室外平台将此4个塔楼连接起来,用于安全疏散时行人通行。由于两相邻平台之间无任何遮挡,且高空来流风速较大,给行人的舒适性与安全性带来极大的隐患,因此有必要对室外平台的行人风环境特性进行研究。考虑到风洞阻塞率的限制和室外平台上测点数量的布置要求,该文设计制作了一缩尺比为1/300的三平台式节段模型,并进行风环境试验,研究了室外平台行人高度的平均风速与阵风风速特性,并探讨不同高度和形式的挡风板对风环境特性的改善效果,为该摩天大楼的行人风环境评估奠定基础。结果表明:外围塔楼与中心塔楼之间存在明显的"狭管效应",导致行人高度风速比增大,基准模型的最大平均风速比和最大阵风风速比分别达到1.49和1.72。不同挡风板措施,不论在降低行人高度最大风速比,还是改善行人风环境的整体质量,均有效果。其中,挡风板高度或挡风板+导(抑)流板的总高度为20 mm时效果更为显著。

A thousand-meter-scale megatall building, which consists of three equilateral-triangle arranged tear-drop towers and a central circular tower, has 10 outdoor platforms along its height with an interval of 100 m to connect the towers. The outdoor platforms are served as the emergency passageways for evacuation. As there is no shelter between two adjacent platforms, wind can pass through the building with high speed and hence cause discomfort and even danger to the pedestrians. Therefore, it is necessary to study the characteristics of the pedestrian wind environment on the platforms to guide its architectural design. Considering the limitation of blocking ratio of the wind tunnel and the requirement of sufficient measuring points on the platforms, a three-platform sectional model （abbreviated as the sub-configuration） of the megatall building with a length scale of 1/300 is employed to conduct the wind environment experiment. The characteristics of the pedestrian mean wind speed and gust wind speed on the platforms are studied, and the influence of the outdoor platforms with different wind shield heights and forms on characteristics of the wind environment is discussed. This study improves understanding of characteristics of the pedestrian wind environment of outdoor platforms high up on megatall buildings, and lays a solid foundation for its wind comfort and wind safety assessment. The results show that there is significant ＂funneling effects＂ in the narrow passageways of two adjacent towers. The wind speed is accelerated, and the maximum pedestrian mean wind speed amplification factor and pedestrian gust wind speed amplification factor reach 1.49 and 1.72, respectively. Moreover, the aerodynamic measures with different wind shields, especially for the outdoor platforms with higher wind shields, are very effective in reducing the maximum wind speeds amplification factor, and improving the whole quality of pedestrian wind environment.