Aeroelastic and aerodynamic wind tunnel tests for tall buildings

Starting from the consolidated concept of aerodynamic model, a benchmark is proposed to further asses an extend its capability of correctly identify the dynamic response of a tall building, devoting particular attention to the contribution of higher-order modes and the possible presence of aerodynamic damping. Being the extrema ratio in terms of accuracy and reliability, a full-aeroelastic model of a tall building is presented as the subject of comparison. The complexity involved in the dynamic wind-tunnel scaling led to the definition of a novel semi-automatized procedure. Based on the author’s experience, developed during the project, each step comes with practical advice, often challenging to find in the scientific literature, and food for thought on the worthiness of design-oriented aeroelastic modeling approach. The design, construction, identification, and validation of a 1:360-scale, a four-level lumped-mass aeroelastic model of the well-known Caarc standard tall building, is presented. Differently to the numerous previous research involving the Caarc building, here it is disclosed in a new guise, featuring torsional and second-order modes, enhancing the challenge for the aerodynamic model test. An extensive experimental campaign is performed at the CRIACIV boundary layer wind tunnel. Tests are performed in turbulent flow for a wide range of velocities and varying the structural damping to be able to address the results for different design criteria. Although the aerodynamic model is generally found to provide useful insight in the building response, the presence of aerodynamic damping and second-order modes are found to be relevant both in terms of base moments and acceleration. From a design perspective, even for "not exceptional" tall buildings, such as the Caarc, the aerodynamic model seems a valid option for early design stages, while the adoption of an aeroelastic model might be a valuable solution in the refinement of loads or serviceability criteria.