Prediction of dynamic loads and responses of a tall building in tornado wind: Numerical analysis and experimental validation

Abstract

The aerodynamic loads and responses under non-synoptic wind events, such as tornadoes, exhibit a transient nature and have not been thoroughly explored for tall buildings to date. This study extends a time-domain method, previously developed for straight-line winds, to predict dynamic loads and responses of a 1:350 scaled tall building model under non-stationary tornado wind. The method uses 2DOF response equations for a tapered tall building with a circular cross-section, incorporating aerodynamic load parameters from straight-line wind tunnel tests and wind speeds from experimental data measured in the ISU-Tornado Simulator (ISU-TS). The motion-induced self-excited loads are modelled using flutter derivatives, while buffeting loads are simulated using buffeting indicial derivative functions. Numerical simulations of wind-induced responses were validated against experimental responses from a laboratory tornado test on an aeroelastic model of the tapered circular tall building. The results for peak accelerations showed close alignment between numerical and experimental responses, with errors within 7.5–16 %. The study emphasizes the importance of accurately defining wind field and structural parameters for predicting dynamic responses. This approach enhances wind tunnel facilities' ability to investigate the impact of non-stationary tornado winds on structural load and response. • Time-domain method for prediction of 2DOF wind response of a tall building. • Comparison of predicted and model response of a tall building in tornado wind. • Proposed method can be used for non-synoptic wind events. • Parametric study on effects of taper, mass, damping on building response. • Predicted response closely matched experimental ones with an error of less than 16 %.

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