Wind tunnel test on across-wind aerodynamic damping of rectangular super-high-rise buildings

The mechanism of aerodynamic damping in cross-wind is very complicated. No widely adopted theory and sophisticated method are available up to date, with no relevant guidelines in the load standards and codes in most countries. In order to investigate the effects of roughness exposure, aspect ratio and side ratio on acrosswind aerodynamic damping ratio, the random decrement technique is used to evaluate across-wind aerodynamic damping ratios from wind-induced acceleration responses of 15 aeroelastic models. The evaluated-results are compared with previous research achievements. The characteristics of across-wind aerodynamic damping ratio of rectangular high-rise buildings are studied. Results indicate turbulence intensity and side ratio are the most important factors affecting across-wind aerodynamic damping ratio. Aspect ratio indirectly affects aerodynamic damping ratio through making change of response amplitude. For the variation rule of aerodynamic damping ratio with reduced wind velocity, both of the magnitudes of positive and negative peaks decrease as turbulence intensity increases. Meanwhile, reduced wind velocity, from which aerodynamic positive damping ratio changes to negative damping, increases as turbulence intensity increases. Side ratio has significant influence on across-wind aerodynamic damping ratio, and completely different tendency are observed for B/D<1, B/D=1 and B/D>1. According to the database, empirical aerodynamic damping functions are proposed to estimate aerodynamic damping ratios at low reduced velocities for rectangular super-high-rise buildings with an aspect ratio in the range of 5 to 10, a side ratio of 1/3 to 3, and lateral turbulence intensity varying from 0.67% to 17.06%.