超高层建筑的风效应实测研究

发布时间：2018-05-10 23:04

本文选题：超高层建筑 + 风效应实测　；参考：《华南理工大学》2014年硕士论文

【摘要】：目前，风工程界主要采用风洞试验方法对超高层建筑进行抗风研究。现场实测作为风工程研究中一项非常重要的基础性和长期性工作，其研究工作及相关成果均显不足，原型实测与风洞试验这两种研究手段的比较验证工作则更加匮乏。阻尼比作为影响结构动力响应的控制性参数，其取值大小对结构风致振动控制具有决定性作用，现有大量文献表明：结构响应幅值对结构阻尼比值有较大影响，两者呈现出非线性关系，这与经典的结构动力学方程中，阻尼比作为一个常数存在较大出入，因此结构响应幅值对阻尼比识别结果影响的研究对抗风实测研究中信号处理的准确性具有重大意义。本文主要从模拟信号阻尼比、超高层建筑的现场实测及风致响应、风洞试验等问题展开研究： 1、由随机减量技术(RDT)得到模拟信号衰减曲线后，用外包络和四参数拟合信号阻尼比。用外包络拟合由不同初始阈值系列得到RDT衰减曲线阻尼比，过大、过小的初始阈值得到的阻尼比误差比较大，过小初始阈值得到信号阻尼比还呈现较大离散性。对不同的随机信号，阻尼比随初始阈值变化趋势不一致。取一倍均方根作为初始阈值时得到的阻尼比最为接近预设值；运用四参数拟合长时RDT衰减信号得到结构模态参数，其中频率值与预设值一致。阻尼比值在大幅值情况下误差很小，在小幅值情况下识别得到的阻尼比误差较大，也呈现出离散性；对于同一衰减信号由外包络拟合阻尼比值和四参数拟合阻尼比平均值，在大幅值情况下基本相等。而在小幅值情况下，结果误差较大，也呈现出离散性，但两者变化趋势一致。 2、对深圳卓越皇岗世纪中心在不同强、台风条件下实施不间断监测表明：结构舒适度满足规范要求；由四参数、功率谱得到结构前两阶频率值均为0.80Hz、0.220Hz左右；由外包络、四参数拟合得到结构的前2阶模态阻尼比分别为0.8%、0.9%左右，并没有呈现随结构加速度幅度增大而增大的趋势。由环境激励加速度响应得到的阻尼比呈现出较大波动性，误差较大，，此时RDT衰减曲线得到阻尼比值准确性得不到保障。 3、深圳卓越皇岗世纪中心刚性模型高频底座天平试验计算表明：结构10年重现期峰值加速度约为18mg，满足规范舒适度要求；分析一阶广义力功率谱函数得到180°风向角下结构折算频率与斯托罗哈数0.1接近，因此在该风向角下出现了较大加速度值和基底弯矩值；对实测建筑频率与有限元模型分析得到，实测频率加速度响应小于有限元模型频率加速度响应，实际结构中，非承重构件增加了结构刚度，有限元模型周期应折减。对比实际风场环境测得加速度响应与刚体模型在相应风场环境中加速度响应存在较大差距，在相同阻尼比情况下，风洞试验得到加速度值大于实测值。分析其原因可能与来流风场的基本风速、风向均与结构实际响应对应风速、风向不一定准确，风洞试验的缩尺效应也可能造成与实测结果的不一致，结构模态阻尼的识别方法也可能导致计算结果产生偏差等有关。
[Abstract]:At present, wind engineering field mainly adopts wind tunnel test method to study wind resistance of super high rise buildings. Field measurement is a very important basic and long-term work in wind engineering research, and its research work and related achievements are insufficient. The comparison and verification of the two methods of prototype measurement and wind tunnel test are more scarce. The damping ratio is a controlling parameter that affects the dynamic response of the structure. The value of the damping ratio plays a decisive role in the wind induced vibration control of the structure. A large number of existing documents show that the amplitude of the structural response has a great influence on the damping ratio of the structure, and there is a nonlinear relationship between the two. The damping ratio is a constant in the classical structural dynamic equation. There are great differences in number, so the research on the influence of structural response amplitude on damping ratio identification results is of great significance to the accuracy of signal processing in wind measurement research. This paper mainly studies on the damping ratio of analog signals, field measurement and wind response of super high rise buildings, wind tunnel test and other problems.
1, after the simulation signal attenuation curve is obtained by random decrement technique (RDT), the damping ratio of the signal is fitted with the external envelope and the four parameter. The damping ratio of the attenuation curve of the attenuation curve is obtained by the outer envelope fitting from the different initial threshold series. The damping ratio is larger than the initial threshold, and the damping ratio of the signal is also obtained by the small initial threshold. Large dispersion. For different random signals, the damping ratio is not consistent with the change trend of the initial threshold. The damping ratio obtained by taking the root mean square root as the initial threshold is most close to the preset value; the modal parameter is obtained by fitting the long RDT attenuation signal with the four parameter, in which the frequency value is in accordance with the presupposition value. The damping ratio is in the case of large value. The error is very small, the damping ratio identified by the small amplitude is larger and shows discreteness. For the same attenuation signal, the damping ratio of the outer envelope and the mean value of the four parameter fitting damping ratio are basically equal in the case of large value. In the case of small amplitude, the result is large and discreteness, but both change. The trend is consistent.
2, uninterrupted monitoring of the center of Shenzhen's outstanding Huanggang century under the condition of typhoon shows that the structural comfort meets the requirements of the standard, and the two order frequency values of the structure are all 0.80Hz and 0.220Hz, from the four parameters, the power spectrum is about 0.8% and 0.9% of the first 2 order modal damping ratios of the structure from the outer envelope and the four parameters. It does not show a tendency to increase with the increase of the acceleration of the structure. The damping ratio obtained by the response to the acceleration response of the environment presents a larger fluctuation and the error is larger. At this time, the RDT attenuation curve gets the damping ratio accuracy not guaranteed.
3, the calculation of the high frequency base balance test of Shenzhen outstanding Huanggang Center rigid model shows that the peak acceleration of the 10 year recurrence period of the structure is about 18mg, which meets the requirements of the standard comfort degree. The analysis of the first order generalized force power spectrum function is close to the Stow Lodha number 0.1 under the 180 degree wind direction angle, so it appears under the wind direction angle. In the actual structure, the structural stiffness of the non load-bearing component is increased and the period of the finite element model should be reduced. The acceleration response and the rigid body measured in the actual wind field environment are measured and the acceleration response and the rigid body are measured in comparison with the actual wind field. There is a large gap in the acceleration response of the model in the corresponding wind field. In the case of the same damping ratio, the acceleration value of the wind tunnel test is greater than the measured value. The reason may be the basic wind speed of the wind field, the wind direction is corresponding to the actual response of the structure, the wind direction is not accurate, and the scale effect of the wind tunnel test may also be caused by the wind tunnel test. The method of structural modal damping identification may also lead to bias in calculation results, which is inconsistent with the measured results.

【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU973.213

【参考文献】