基于扭转强迫振动风洞试验的矩形截面高层建筑三维风荷载研究

Three-dimensional wind loads of rectangular tall buildings based on torsional forced vibration wind tunnel tests

为了研究扭转振动对高层建筑三维气动力的影响,利用扭转强迫振动装置,通过多点测压风洞试验测试了三个矩形截面高层建筑模型在不同试验风速和不同扭转振幅情况的表面风压时程。进而讨论了结构顺风向、横风向和扭转向均方根风力系数及功率谱的变化规律,研究结果表明:结构顺风向、横风向和扭转向均方根风力系数均随着试验风速和扭转振幅的变化而变化;结构顺风向阻力系数随着扭转振动振幅的变化主要是由于结构顺风向气动力的变化引起,而其横风向和扭转向风力系数随着扭转振动的变化包含了气动力变化与结构气动弹性效应两部分。对于高层建筑来说,应考虑扭转振动引起的结构三维气动力的变化以及结构横风向和扭转向气弹效应。

In order to study the effects of torsional vibration on three-dimensional aero-dynamic forces of tall buildings,the wind pressure time series of three models of rectangular tall buildings under different test wind speeds and torsional vibration amplitudes were measured through measuring pressure wind tunnel tests and applying a torsional forced vibration device. Further more,the characteristics of root mean square（ RMS） wind coefficients and wind load power spectra in alongwind, acrosswind and torsional directions were discussed. The results showed that the RMS wind coefficients in alongwind,acrosswind and torsional directions vary with wind speeds and torsional vibration amplitudes; the variation of RMS alongwind resistance coefficients with torsional vibration amplitudes is caused due to the variation of dynamic wind loads on structures; the variations of RMS acrosswind and torsional wind force coefficients are caused due to the variations of the dynamic wind loads and the aero-elastic effects; for tall buildings,the variations of dynamic wind loads in alongwind,acrosswind and torsional directions and the aero-elastic effects in acrosswind and torsional directions induced by torsional vibration should be considered.