Wind tunnel test and analysis method for segmented-rigid models of super-tall high aspect-ratio buildings

Abstract

Traditional wind tunnel testing technologies face challenges from super-slender buildings and skyscrapers with large aspect ratios. These buildings are difficult to fit into typical boundary layer wind tunnels with an acceptable geometric scale. Limited research has been conducted into overcoming this issue by combining wind tunnel test results of multiple building sections. This study proposes a more precise and comprehensive sectional model wind tunnel testing and analysing method to address this gap. The high-frequency pressure integration method is selected for its ability to accurately capture sectional model surface pressure distributions. Two super-slender building models—a 2D pressure-tapped circular cylinder and a 2D pressure-tapped rectangular prism—are used to investigate the method. A case study demonstrates the application of the proposed method to an actual commercial building project in an urban setting. Experimental testing includes subjecting the 2D models to uniform flow conditions with varying turbulence intensities and Reynolds numbers. The correlation mechanisms of drag and lift with different separation distances for these two models in diverse flow conditions have been thoroughly investigated. Shear flow conditions, simulating those in skyscraper cities like Shanghai, are also examined. The study introduces a method to synthesise the time series of wind loads along the building height, ensuring the synthetic signal embodies the characteristics of simultaneous sampling. The mathematical derivation of the synthetic wind load (SWL) method is validated through comparisons of wind load cross-spectra and dynamic responses of a hypothetical chimney. Furthermore, the study investigates the effects of structural mode shape, model split position, the number of horizontal pressure-tap lines, and the number of tested sectional models on the SWL method for both representative Reynolds number-dependent and independent models. The SWL method's feasibility is demonstrated through combining sectional wind loads from different tests on a 3D model. In summary, this research pioneers the development and validation of the SWL method, offering a robust solution for wind tunnel testing of very high aspect ratio buildings. The method reproduces the deflection prediction of a high aspect ratio building within 10% accuracy compared to the prediction using a full building model, addressing challenges in segmented-rigid model testing.