开敞式叶片形空间网格结构风荷载及风振响应实测研究
发布时间：2018-07-13 11:34
【摘要】：大跨空间结构是风敏感结构,风荷载和风致振动常常是控制结构安全的主要因素。随着我国经济的发展和技术水平的提高,大跨空间结构被越来越多地应用到现代工程中。然而近年来也有一些大跨空间结构在风荷载作用下发生破坏。基于此,大跨空间结构抗风设计越来越受到工程人员的重视。本文数据来源于开敞式叶片形空间网格结构屋盖实测风荷载及风振响应。通过在上下屋盖对应布置12对风压传感器,实时测量屋盖表面的风荷载信息,通过现场风速仪记录对应时刻的来流信息,通过在屋盖布置速度传感器测量结构风致速度响应。基于实测风速,分析来流的风速谱与湍流强度,研究发现不同时段的风速谱纵坐标略有不同,但是曲线整体变化规律一致。与经典的Davenport谱、Von Karman谱和Kaimal谱比较,在中低频段,实测风速谱曲线与经典谱曲线基本一致；在高频段,两者则有较大差异。由于后期新增建筑对场地的影响,场地粗糙度(结构设计取为B类地貌)发生变化,实测湍流强度位于C类与D类之间,与日本规范Ⅳ地貌湍流强度相当,说明建筑设计要考虑后期规划建筑对场地粗糙度的影响,否则建筑可能偏于不安全。分析了实测风压频谱特性,考察了测点之间的相关系数,测点之间的相关系数绝对值均少于0.2,属于弱相关。其原因一方面是各测点之间的距离较大,且上下屋面不透风,空气对流较少；另一方面是风压测点集中布置在屋盖中间区域,距离风压复杂的屋檐、拐角区域较远。分别利用峰值因子法、Hermite级数法和sadek-simiu法三种方法计算得到了实测风压的峰值因子,比较了三种计算结果的差别及峰值因子的变化范围,给出了该类开敞式空间网格结构的峰值因子建议取值。与标准高斯分布概率密度曲线相比,实测风压概率密度曲线对称性较好,在曲线尾部较标准高斯曲线略高。实测风压偏度和峰态较一般风洞试验结果小,实测风压非高斯特性并不明显。根据偏度和峰态的曲线关系及其累计分布函数,提出了风压非高斯区域划分依据。基于实测风压功率谱及概率统计参数,分别采用Yamazaki-Shinozuka方法和Forrst-Gurley方法模拟了风压时程,两者功率谱吻合较好,同时表征非高斯特性的偏度、峰态参数也在合理误差范围内。基于结构实测振动速度响应,分别利用随机减量法、峰值拾取法和频域分解法得到了结构实测自振频率和竖向振动模态,对比有限元模型频率及模态结果,两者自振频率误差在10%以内,且结构竖向模态吻合较好。采用多项式拟合数据去除趋势项方法得到了积分位移信号,分析位移信号,结构振动较小,且呈现周期性。本文应用现场实测方法,综合研究了大跨结构的风致响应与风荷载特性。研究成果可丰富大跨结构风效应的知识和抗风设计方法,同时可为大跨建筑的设计与建造提供有科学意义的参考。
[Abstract]:Long span space structure is a wind sensitive structure. Wind load and wind induced vibration are often the main factors to control the safety of the structure. With the development of economy and the improvement of technology, large span space structure is applied to modern engineering more and more. However, in recent years, some large span space structures have been damaged under wind load. Based on this, the wind-resistant design of long-span space structure is paid more and more attention by engineers. The data in this paper are derived from the measured wind loads and wind-induced vibration responses of open vane space grid structures. By arranging 12 pairs of wind pressure sensors corresponding to the upper and lower roof, the wind load information on the roof surface is measured in real time, the flow information at the corresponding time is recorded by the field anemometer, and the wind induced velocity response of the structure is measured by placing the velocity sensor in the roof. Based on the measured wind speed, the wind velocity spectrum and turbulence intensity are analyzed. It is found that the longitudinal coordinates of wind speed spectrum are slightly different in different periods, but the overall variation of the curve is consistent. Compared with the classical Davenport spectrum Von Karman spectrum and Kaimal spectrum, the measured wind velocity spectral line is basically the same as the classical spectral curve in the middle and low frequency range, but there is a great difference between them in the high frequency range. Due to the influence of the new buildings on the site, the roughness of the site (structural design is taken as B geomorphology) is changed. The measured turbulence intensity lies between class C and D, which is equivalent to the turbulence intensity of the Japanese code 鈪，
本文编号：2119223
[Abstract]:Long span space structure is a wind sensitive structure. Wind load and wind induced vibration are often the main factors to control the safety of the structure. With the development of economy and the improvement of technology, large span space structure is applied to modern engineering more and more. However, in recent years, some large span space structures have been damaged under wind load. Based on this, the wind-resistant design of long-span space structure is paid more and more attention by engineers. The data in this paper are derived from the measured wind loads and wind-induced vibration responses of open vane space grid structures. By arranging 12 pairs of wind pressure sensors corresponding to the upper and lower roof, the wind load information on the roof surface is measured in real time, the flow information at the corresponding time is recorded by the field anemometer, and the wind induced velocity response of the structure is measured by placing the velocity sensor in the roof. Based on the measured wind speed, the wind velocity spectrum and turbulence intensity are analyzed. It is found that the longitudinal coordinates of wind speed spectrum are slightly different in different periods, but the overall variation of the curve is consistent. Compared with the classical Davenport spectrum Von Karman spectrum and Kaimal spectrum, the measured wind velocity spectral line is basically the same as the classical spectral curve in the middle and low frequency range, but there is a great difference between them in the high frequency range. Due to the influence of the new buildings on the site, the roughness of the site (structural design is taken as B geomorphology) is changed. The measured turbulence intensity lies between class C and D, which is equivalent to the turbulence intensity of the Japanese code 鈪，
本文编号：2119223
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