Pedestrian-level wind environment on outdoor platforms of a thousand-meter-scale megatall building: Sub-configuration experiment and wind comfort assessment

A thousand-meter-scale megatall building is consisted of three peripheral elliptical towers and one central circular tower, together with 10 outdoor platforms along the height with an interval of 100 m to connect the four towers. As there is no shelter between every two adjacent platforms, pedestrians will feel uncomfortable or unsafe due to large approaching wind speed when strolling or walking across the platforms. Therefore, the pedestrian-level wind environment on outdoor platforms is studied via the combination of wind tunnel tests and CFD simulations. Firstly, wind environment experiment of a sub-configuration of the megatall building is carried out, and characteristics of the pedestrian-level wind environment are analyzed. Then, distributions of the pedestrian-level wind speeds of a full model of the megatall building are compared to that of the sub-configuration via CFD simulations, and an adjustment coefficient is introduced to establish the link of wind speeds between these two models. Lastly, based on the statistical meteorological data provided by the Dalian Meteorological Service Center and the aerodynamic information above, assessment of the pedestrian-level wind comfort and wind danger of the outdoor platforms is implemented using both the Lawson criterion and the NEN 8100 criterion. The results show that quality of the wind environment is very poor on most zones of the platforms, especially in the passageways of two adjacent towers due to the “funneling effects”, and some effective measures should be explored to improve it. This study contributes to further understanding of characteristics of the pedestrian-level wind environment of outdoor platforms high up on megatall buildings via sub-configuration experiment and full model simulations.