Research on Mechanism of Collapse by Aero-elastic Instability of a Tall Building

研究了高层建筑在涡激振动、驰动和扭转颤振等气动弹性失稳作用下的倒塌过程。为了实现这一目标，采用常规万向节闭锁振动模式，对高层建筑在平流和湍流中的动力特性进行了风洞试验研究。试验结果表明，失稳临界速度和失稳初始阶段的响应几乎不受结构阻尼的影响，而受建筑物质量的影响。在假定建筑物的失稳早期都伴随着旋涡脱落，并且旋涡脱落的频率可以通过考虑振动幅值的有效宽度来确定的前提下，建立了预测上述失稳行为的解析模型。该模型可以预测风洞试验中的各种动力行为。该装置是为了研究建筑物在失稳状态下的弹塑性行为而研制的。该装置通过给力反馈来控制万向节，实现系统中建筑物的弹塑性行为。通过与传统框架的失稳响应比较，该装置可用于建筑物弹塑性特性的研究。

The objective of this research is to investigate the process of collapse of a tall building by occurrence of an aero-elastic instability like vortex induced vibration, galloping and torsional flutter. In order to achieve the objective, wind tunnel tests have been performed to investigate the dynamic behaviors of tall buildings in smooth and turbulent flows using conventional gimbals vibrating in locking modes. From the tests, the critical velocity of the instability and the response at the initial stage of the instability hardly affected by structural damping, but affected by mass of the building.The analytical model for predicting the above behavior of the instability has been developed by the assumption that any instability of buildings is accompanied by the vortex shedding at the early stage and the frequency of the vortex shedding can be determined by the effective width considering the amplitude of the vibration. The model can predict the various dynamic behaviors in the wind tunnel tests.The new device is developing in order to investigate the elastic-plastic behaviors of the building in the instability. The device can control the gimbals by giving the feed-back force to realize the elastic-plastic behaviors of the building in the system. By the comparison of the response of the instability between the new device and the conventional gimbals, the device can be used in the investigation of the elastic-plastic behaviors of the building.