Abstract: Vibration is a problem that the construct can’t avoid，SO handling the knowledge of the dynamic characteristics such as natural frequency and quake pattern.Can make US avoid the loss that results from resonance.The modal analysis is made to ascertain the dynamic characteristics，and to get the natural frequency and vibration pattern.Based on the accurate medal analysis of complex system structure，vibration diagnostic program and refimng the dynamic characteristics can be performed.Finite.element method is used to analyze the med al of Guanlei Wharf Bridge crane structure and ten modals have been abstracted .From these medals.critical medals are found out and their influences on the structure are illustrated.Considering the actual conditions，the self-vibration security estimation is given under the basic work condition.

Key words: bridge crane, container wharf, finite element method, dynamic characteristics of structure, medal

摘要： 振动是结构经常面对的问题之一，因此了解结构本身具有的刚度特性即结构的固有频率和振型，将避免在使 用中因共振因素造成不必要的损失．所谓的模态分析就是确定设计结构的振动特性，得到结构的固有频率和振型， 对复杂结构进行准确的模态分析将对结构系统的振动特性分析、振动故障诊断以及结构动态特性的优化设计提供 依据．用有限元法对关累码头桥吊结构进行了模态分析，得到了1O阶模态，并挑选出关键模态，分析了其对结构的影 响，最后结合该码头的实际情况，给出了其基本工况下的振动安全性评价．

关键词: 桥吊, 集装箱码头, 有限元法, 结构动力特性, 模态