Torsional response and interference effect of wind-excited tall buildings

A series of wind tunnel model tests were performed to investigate the torsional response of a tall square building and interference effects from neighbouring buildings with different sizes and shapes. The tall square building model, called the principal model, was tested by using an aeroelastic test rig designed for pure torsion vibration. Four types of interfering models were used to provide interference by individually locating each of them at positions upstream and downstream of the principal model. The aeroelastic test results of the isolated building model were compared with those obtained by pressure measurements and multi-degree aeroelastic tests, and used as a reference for estimating interference effects. It was found that significant torsional response occurred when the principal building was under interference. The dynamic torsional response increased by up to 2.2 times that of the isolated building. However, in some positions, the proximity effect provided by the interfering models reduced the torsional response. The critical relative locations of the interfering models were identified and possible torsional excitation mechanisms were discussed.