2024 Volume 70B Pages 18-25
Aerodynamic and response characteristics of a square- and rectangular-plan tall building models with various aspect ratios were investigated through a series of wind tunnel tests under the flow conditions representing the suburban area. The cross-sectional areas were designed to be the same and the aspect ratios were changed from 2 to 9.5. It was found that the effect of the side ratio on mean and fluctuating force coefficients in X-direction was found to be small. But, clear differences were found on force coefficients in Y-direction, showing larger values for the square-plan model. From the Den Hartog criterion, an aerodynamic instability could occur for the square-plan models with the aspect ratio larger than 3 and the rectangular-plan models with the aspect ratio larger than 2 for the wind direction which is normal to the long side of the model. Correlation length scale increases with the aspect ratios, showing larger values in X-direction than those in the Y-direction. Lastly, tip displacements and peak accelerations were calculated based on a spectral modal method. Both responses increase with the aspect ratio and the tip displacements of the square-plan model become larger than those of the rectangular-plan model when the aspect ratio is larger than 6.5. However, peak accelerations of the square-plan model were larger than those of the rectangular-plan model for all the aspect ratios.
