Effects of corner modifications on wind-induced responses of super high-rise buildings by wind tunnel tests based on a novel low-damping elastic test model

Abstract

Corner modification is a useful aerodynamic countermeasure to reduce wind-induced responses of super high-rise buildings. In this paper, the effects of corner modifications on wind-induced responses of super-tall buildings with square section were carefully studied by using wind tunnel tests based on a low-damping elastic test model, from which the aeroelastic effect can be taken into account. First, an elastic test model of a 452-m-high building with low damping was designed and manufactured. In this test model, a core beam with a cross-shaped section was adopted to provide the essential stiffness. Four types of coats with different corners, including right-angle, recessed, chamfered and rounded, were specially designed to conveniently change the configurations of the elastic test model. Second, the frequency and damping ratio of the elastic test model were identified experimentally. The measured frequencies of the test model are in good agreement with the target frequencies, and a very low damping ratio of 0.3% and 0.5% were achieved. Third, a series of wind tunnel tests on the elastic test models were carried out to measure the wind-induced responses of the buildings with different corner modifications, including the accelerations at the top, the base shears and moments at the bottom. The results show that the three types of corner modifications, including recessed, chamfered and rounded corners, all play an important role in reducing the cross-wind and along-wind responses. It seems that the optimized parameters for the recessed, chamfered and rounded corners are respectively 3%, 7.5% and 10% from the viewpoints of both the peak and RMS base moments. 15.3%, 23.4% and 18.9% of the maximum peak base moment in the cross-wind direction can be reduced by the optimized parameters of the recessed, chamfered and rounded corners, respectively. The values in the along-wind direction (RMy) are 15.2%, 22.3% and 21.1%, respectively. As for the acceleration at the top, the RMS acceleration of the building with the three types of corners can all be significantly reduced up to 90% for wind attack angle of α = 15°, 30° and 45°.