【作者】 嵇学培；

【导师】 谢壮宁；

【作者基本信息】 汕头大学 ， 防灾减灾工程及防护工程， 2008， 硕士

【摘要】 随着社会的发展、科学技术的进步和城市化进程的加快,高层、超高层建筑得到了迅猛地发展。由使用新材料、新工艺和新的施工技术建造起来的超高层建筑通常是轻质高柔性结构,这类建筑对于风环境特别敏感,风荷载已成为超高层建筑的重要控制荷载。大量实验表明,超高层建筑的横风向动力响应通常要比顺风向的大。在工程应用中,横风向的等效静态风荷载有时甚至起到了决定性的作用。对一些高柔轻质建筑而言,其结构与风之间的相互作用,有时会使结构响应急剧放大而导致结构不稳定乃至破坏,影响结构使用和安全。因此,需要对此类结构进行气动弹性效应影响的研究。在建的432m广州珠江新城西塔为典型的高柔性结构,本文以此为原型,设计制作了气动弹性模型,考察这一重要工程结构的气动弹性效应。首先通过静力拉伸法测量并估算结构阻尼,发现了模型结构阻尼随响应振幅的增加而增加的规律。通过一系列风洞试验,运用随机减量技术(RDT)识别出了结构的动力响应参数,分析了结构的气动阻尼特性。结果表明:西塔的横风向气动阻尼基本上均为正数,在低风速段随风速的增加而增加,在梯度风风速为45.4m/s时达到最大值为1.75%;随后在临界风速附近急剧下降,在51m/s时降到最小值,约为-0.06%。由于负气动阻尼值的绝对值很小,可以忽略其不利影响。最后在总阻尼识别的基础上,将气弹模型的结果和刚性模型的结果进行了比较,结果显示,两种不同试验方法的结果具有较好的可比性。同时根据高层建筑结构振动控制原理,设计了倒悬质量块的减振装置(TMD)。通过可调质量块来改变减振装置的参数,使其达到较好的减振结果。结果发现:减振参数的选取对减振效果起着重要的作用,减振装置会使结构的固有特性发生改变,而这又会反过来影响结构的减振效果。本文实施的气动弹性模型试验,部分验证了刚性模型试验的可靠性。气弹模型试验得到的气动阻尼特性可以作为西塔结构抗风设计的依据,也可为相关工程提供参考。更多还原

【Abstract】 Modern super tall buildings are usually constructed with innovative structural systems and high strength materials; tend to be more flexible and lightly damped than those in the past. As a consequence, the sensitivity of these buildings to strong wind has increased. Wind load plays the key role in the structural design of those buildings.Massive experiments indicate that wind induced response on super tall buildings in the crosswind direction may be more significant than that in the along-wind direction. For high flexible buildings, the effect of the interaction between the structure and wind on wind induced response and wind loads may also significant. Aerodynamic damping that reflects the effect of the structure-wind interaction often plays an important role in estimations of wind induced dynamic responses of super high-rise buildings. Aero-elastic model test is considered to be the most reliable method for evaluating wind effects on super tall buildings.Guangzhou West Tower (GWT) with a height of 432m is at present the tallest building in south China. In first part of this study, in order to evaluate the aeroelastic effect, an experiment of GWT is firstly carried out using the MDOF aero-elastic model technique in boundary layer wind tunnel. and the results are compared with those of stiffness model based experiment using the high frequency base balance (HFBB) technique. The Random Decrement Technology (RDT) is applied to identify the aerodynamic damping of GWT. Good agreement in wind-induced response is found between the two techniques when same damping ratio is used to calculate the wind induced response in the HFBB approach. Generally, the aerodynamic damping of GWT is positive at large scope of wind speed. The results show that the aerodynamic damping increase with the increase of the wind speed and a maximum aerodynamic damping of 1.74% is found when the wind speed at the gradient wind height is 45.4m/s. Then the aerodynamic damping decrease rapidly near the critical wind speed, and finally a minimum aerodynamic damping of–0.06% is found at wind speed of 51m/s.In part 2, a tuned mass damper (TMD) is applied to reduce the wind-induced vibration of GWT. Wind tunnel experiments are performed to verify the effectiveness of TMD on reducing the wind-induced vibration on super tall building model. The effects of the introduction of a TMD on the vibration of the building model of GWT are analyzed and discussed.Finally, some conclusions are summarized as the reference for the wind-resistant design of GWT.更多还原