摘要
为研究上部支承结构和吊杆构造对吊顶自振特性的影响,对一个每层附有吊顶的空间钢框架进行了振动台试验。通过快速傅里叶变换（FFT）和随机子空间识别（SSI）两种模态识别方法获得了吊顶系统的自振频率和阻尼比,给出了吊顶阻尼比的建议值为2%～5%。对主附结构（上部支承结构＋吊顶）的自振特性进行了数值模拟,结果表明：吊杆构造形式对吊顶的第1阶水平和竖向模态没有明显影响,上部支承结构自振频率的不同会对吊顶的竖向模态产生影响,而对水平模态没有明显影响。通过改变上部支承结构的截面尺寸和附加质量对主附结构的竖向模态进行了参数化分析,得到仅考虑附加吊顶质量的上部支承结构的第1阶竖向自振频率小于不考虑上部支承结构影响的吊顶第1阶竖向自振频率fb时,主附结构的第1阶竖向振型表现为上部支承结构和吊顶的整体振动,而大于fb时,第1阶竖向振型表现为吊顶的独立振动。
In order to investigate the influence of the upper supporting structures and hanger rods on the vibration characteristic of suspended ceilings, the shaking table test of a space steel frame with a suspended ceiling attached to each floor was conducted. Two modal identification methods of fast Fourier transform （FFT） and stochastic subspace identification （SSI） were used in the test data processing. The natural frequency and damping ratios of the suspended ceiling systems are obtained, and the recommended suspended ceiling damping ratio is 2%-5%. Numerical simulations of the vibration characteristics of the primary-secondary structures （upper supporting structure and suspended ceiling） were carried out. The finding is that the type of hanger rods has little influence on the first order mode of the suspended ceiling in vertical and horizontal directions. The upper supporting structure with different frequency has certain influence on the modes of the suspended ceiling in vertical direction while not in horizontal direction. By means of changing sectional dimensions and added mass of the upper supporting structures, it is found that when the first order vertical natural frequency of the upper supporting structure with the added mass of the suspended ceiling is lower than the first order vertical natural frequency fb of the suspended ceiling ignoring the influence of the upper supporting structures, the first vertical mode shape of the primary-secondary structure becomes coupled vibration ; but if it is larger thanfb , only the suspended ceiling＇ s vibration will occur in the primary-secondary structure in the first vertical mode of vibration.
作者
韩庆华
赵一峰
芦燕
HAN Qinghua;ZHAO Yifeng;LU Yan(School of Civil Engineering, Tianjin University, Tianjin 300072, China;Key Laboratory of Coast Civil Structure Safety of China Ministry of Education, Tianjin University, Tianjin 300072, China)
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2018年第7期95-103,共9页
Journal of Building Structures
基金
科技部国家重点研发计划课题(2016YFC0701103)
国家自然科学基金项目(51525803,51778411)
天津市应用基础与前沿技术研究计划(自然科学基金)青年项目(17JCQNJC06800)
关键词
吊顶
上部支承结构
振动台试验
自振特性
整体振动
suspended ceiling
upper supporting structure
shaking table test
vibration characteristic
coupled vibration
