Effect of Plan and Height Aspect Ratios on Along-wind and Across-wind Loads on Super High-rise Buildings

Abstract

The Indian standard provides the formulations for the along-wind equivalent static wind load (ESWL) in detail and briefly deals with across-wind load. The present study looks into the relative variation of along and across-wind ESWL for varying plan aspect ratios (0.5 to 2) and height aspect ratios (4 to 9), keeping the height fixed at 300m for all the cases. The plot of design forces versus the height of the building shows that the across-wind forces exceed the along-wind forces at heights above 175 m for buildings with plan aspect ratios of 1 to 2. The magnitude of the across-wind forces is higher than corresponding along-wind forces by about 18 % to 9% at the tip of the buildings for plan aspect ratios of 1 and 2, respectively. However, for increasing height aspect ratio, the across-wind load increases exponentially. Here, across-wind forces at the tip of the buildings have increased by about 18% to 277% over the corresponding value of maximum along-wind force for the height aspect ratios of 6 to 9. Therefore, it is recommended that designers should refrain from planning super high-rise buildings square in plan and keep the height aspect ratio below eight. © 2022 JUST. All Rights Reserved.