Torsional vibration of wind-excited tall buildings and its suppression by tuned mass dampers

A series of wind tunnel model tests and theoretical analyses were conducted to investigate the mechanism of torsional excitation, torsional response of tall buildings, sensitivity of the torsional response to eccentricity between centres of twist and building geometry, as well as the effects of tuned mass dampers on the torsional response of tall buildings. An aeroelastic model for pure torsion vibration was developed at the Fluids Laboratory of the University of Sydney. The aeroelastic test results were compared with those obtained by force balance technique, direct pressure measurement technique and multi-degree-of-freedom aeroelastic models. It is shown that this type of modelling technique can be a convenient and efficient way to explore the mechanism of torsional excitation and predict the torsional response of tall buildings to wind. It is also shown that tuned mass dampers were quite effective in suppressing the torsional vibration of the building if the parameters of the tuned mass damper were properly selected. A reliable and economical parametric study method of tuned mass dampers is presented, which is based on directly measured torsional excitation or response spectra. A mode shape correction factor was used to adjust the mis-match between the model and prototype torsional model shapes.