立交预应力连续箱梁桥的动力测试及分析

荆潜分离式立交桥为三跨一联预应力连续箱梁桥：通过建立该箱梁桥的三维有限元模型，分析得到了其固有频率，并对该桥进行了动力测试及分析。在试验过程中，优选了测点布置及动力测试系统，采用环境随机激励法和模态识别技术得到了其动力特性参数，其结果与有限元分析结果吻合良好。在无障碍行车和有障碍行车2种工况下，测试了该桥的冲击系数和动力响应。最后，对冲击系数的设计取值进行了讨论，并对测试值与我国规范放大谱计算值进行了对比研究？这些为校验桥梁设计的安全性及经济性提供了有力依据。

Dynamic Testing and Analysis of Prestressed Continuous Box Girder Bridge

This paper presented the results from experimental investigations of the dynamic characteristics conducted on Jinqian separate-type overpass, a prestressed three-span continuous box girder bridge. Firstly, the three-dimensional finite element model of the bridge was build up, and the natural frequency was obtained by modal analysis method. Then dynamic testing was carried out. During the testing, the optimization of the measuring point plan and measuring systems were considered, and the parameters of dynamic characteristics were obtained by using environment random excitation method and modal identification technique, which agreed well with the results of finite element analysis. Meanwhile, the impact factor and dynamic response of the bridge were measured in two cases including non-obstacle and obstacle driving. Finally, the evaluation of the impact factor for bridge designs was discussed, and comparative study of the impact factor was conducted between the testing and the amplification spectrum of China's code. The study work obviously played an important role in the evaluation of the safety and economics of bridge design.