Non-Destructive Evaluation of South Temple (I-15) Bridge Structure Through Dynamic Characterization Using an Eccentric Mass Shaker

在接下来的四年里，大约120座桥梁将被摧毁和重建，作为犹他州湖城1-15重建的一部分。 这是一个难得的机会，破坏性测试旧桥梁结构建于20世纪60年代。 研究人员获准进入一座九跨桥，即南寺立交桥。 这座桥将于3月1日左右进行测试，为期约六周。 这座桥的可用性提供了初步的机会，调查使用强迫振动分析和动态特性作为一种非破坏性评估技术的潜力。 桥梁受损后，其动力特性将重新确定。 结构的损伤应该表现在桥梁从未损伤状态到损伤状态的固有频率和振型的变化上。 这种评估方法特别适用于柱和桩帽之间的连接处可能不易看到损坏的结构，或形成的塑性铰可能不会立即明显或被建筑覆盖物隐藏的混凝土结构。 该项目是对结构动力学成熟理论的应用的测试。

Over the next four years approximately 120 bridges will be destroyed and rebuilt as part of the 1-15 reconstruction through Salt Lake City, Utah. This is a rare opportunity to destructively test older bridge structures constructed in the 1960's. The researchers have been given access to a nine span bridge, the South Temple overpass bridge. This bridge will be accessible for testing on about March 1st, for a period of about six weeks. The availability of this bridge provides the initial opportunity to investigate the potential of using forced vibration analysis and dynamic characterization as a non-destructive evaluation technique. After the bridge has been damaged the dynamic characteristics will be redetermined. The damage in the structure should be manifest in the change of the natural frequencies and mode shapes from the undamaged to the damaged state of the bridge. This evaluation approach would be especially applicable to structures where damage might not be readily visible at the joint between a column and pile cap, or concrete structures where plastic hinges that form might not be immediately obvious or hidden by architectural coverings. This project is a test of an application of proven theories of structural dynamics.