Aeroelastic torsional behaviour of tall buildings in wakes

Wind tunnel model tests were performed to investigate interference effects on torsional response of a tall square building from neighbouring buildings with different sizes and shapes. The tall square building model was tested by using an aeroelastic test rig designed for pure torsional vibration. Four types of interfering models were used to provide interference by individually locating each of them at positions upstream and downstream of the square building model. It was found that torsional responses were significantly enhanced by a factor of up to 2.2 times that of the isolated building when vortex shedding from the interfering building was in resonance with the natural frequency of the square building submerged in the wake. The critical relative locations of the interfering models were identified and possible torsional excitation mechanisms were discussed.