Jordan Journal of Civil Engineering

Effect of plan and height aspect ratios on along wind and across wind loads on super high rise buildings


Ashish Singh; Sasankasekhar Mandal;


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 various formulations are available to calculate across wind components of ESWL. One such formulation based on curve fitting of data obtained from wind tunnel, is used to calculate across wind loads to see the effect of plan and height aspect ratio. The present study looks into the relative variation of along and across wind ESWL for varying plan aspect ratio (0.5 to 2) and height aspect ratio (4 to 9), keeping the height fixed as 300m for all the cases. From the plot of the design forces along with the height, it is observed that magnitude of across wind forces exceeds that of the along wind forces at heights above 175 m for the buildings with side ratios 1 to 2. The magnitude of the cross wind forces is higher by 8.66% to 19.22% at the tip of the buildings for side ratio 1 and 2. However, for increasing height ratio, the across wind load increases more rapidly than the along wind load for height ratio 6 to 9. Here, the magnitude of the cross wind forces is higher by 18.1% to 277.4% at the tip of the buildings for height ratios 6 and 9. It is observed that the absolute magnitude of along wind as well as across wind loads, becomes the maximum for square plan buildings. Therefore, it is concluded that slender buildings should be experimentally and theoretically studied in greater detail to ascertain the design wind loads


high rise building, across-wind equivalent static wind load, effect of height and plan aspect ratios