中文摘要：

介绍了联合应用峰值法和互谱法的模态参数识别方法，并提出了一种新的主梁振型优化方法．将上述方法应用于润扬大桥悬索桥的运行模态识别系统中，利用结构健康监测系统采集的振动响应数据获取结构的模态参数．作为应用实例，对台风麦莎作用下的主梁、主缆和桥塔振动响应数据进行了模态参数识别．结果表明：主梁部分振型的模态频率不仅能从主梁的振动响应识别出来，而且能够从主缆和桥塔振动响应中识别，主梁、主缆和桥塔之间存在较强的耦合振动．此外，将运行模态的识别结果和成桥之初的现场测试结果进行了对比，二者识别结果整体上吻合较好，但运行模态系统识别的部分振型模态频率，如L1和L2，发生了较明显的下降．

英文摘要：

An output-only modal identification method by a combination use of the peak-picking method and the cross spectrum methods are presented. Meanwhile, a novel mode shape optimum method of the deck is proposed. The methods are applied to the operational modal identification system of the Runyang Suspension Bridge, which can be used to obtain the modal parameters of the bridge from out-only data sets collected by its structural health monitoring system （SHMS）. As an example, the vibration response data of the deck, cable and tower recorded during typhoon Matsa excitation are used to illustrate the program application. Some of the modal frequencies observed from deck vibration responses are also found in the vibration responses of the cable and the tower. The results show that some modal shapes of the deck are strongly coupled with the cable and the tower. By comparing the identification results from the operational modal system with those from field measurements, a good agreement between them is achieved, but some modal frequencies identified from the operational modal identification system （OMIS）, such as L1 and L2, obviously decrease compared with those from the field measurements.