中文摘要：

本文以广州国际会展中心一期在环境激励下获得的屋盖5处位置加速度响应时程数据为基础,分别采用随机减量法（RDT）、峰值拾取法（PP）以及频域分解法（FDD）识别结构的前4阶竖向振动模态频率;并采用随机减量法（RDT）获得了前2阶阻尼比。基于有限元分析软件ANSYS,建立结构三维有限元模型,获得了结构前16阶模态频率,并将前4阶整体竖向模态频率与实测结果进行对比。研究表明：（1）RDT法、PP法以及FDD法具有很好的识别结构振动模态频率的功能,且RDT法能有效地识别结构整体阻尼比;（2）有限元数值计算在结构设计初期对识别动力特性上具有较高的精度。

英文摘要：

The acceleration responses of five accelerometers located on the roof of the Guangzhou International Con- vention ＆ Exhibition Center （GICEC） were obtained under the condition of the ambient excitation. Three methods of random decrement technique （RDT）, peak picking （PP）, frequency domain decomposition （FDD） were adopt- ed for the identification of the first four vertical vibration modal frequencies, and the first two modal damping ratio were identified by means of RDT method. The 3-D finite element model （FEM） was built with the software of AN- SYS, then the first sixteen modal frequencies were extracted. Meanwhile, the first four vertical vibration modal fre- quencies were compared with that from the field measurement. The results revealed that： First, the methods of RDT, PP, and FDD are efficient to identify the structural modal frequency, and the RDT method has high accuracy for estimation of the structural damping ratio. Second, the 3-D FEM has a good accuracy for predicting the structure dynamic characteristics in its prior period design stage.