Prediction of along-wind loading on tall building based on two-dimensional aerodynamic admittance

Abstract

The mismatch of simulated turbulence integral scale may occur in some wind tunnel model tests, especially in a short wind tunnel, which would lead to inaccurate prediction of the wind loading based on traditional aerodynamic admittance (traditional AAF) containing the three-dimensional effect (3D-effect). For this, a method for prediction of along-wind loading on tall building based on two-dimensional aerodynamic admittance (2D-AAF) is introduced. The key to the method is to identify the 2D-AAF which does not contain the 3D-effect through separating the 3D-effect from the traditional AAF. With this method, the 2D-AAFs of the along-wind loading of a CAARC building model in two turbulent flow fields with different turbulence integral scales are identified. As expected, the traditional AAF which contains 3D-effect changes with the turbulent flow field because 3D-effect is related to the turbulence integral scale. Different from the traditional AAF, the 2D-AAFs obtained in two different turbulent flow fields are almost consistent, confirming that the 2D-AAF is independent of the turbulence integral scale. An empirical expression for the 2D- AAF of along-wind loading of CAARC building is then proposed by fitting the experimental data. A comparison between the high-frequency-force-balance (HFFB) measurements conducted in a simulated boundary layer flow field and the prediction values shows that the reproduced spectrum of along-wind loading based on the 2D-AAF has high accuracy, verifying the validity of proposed prediction method.