RAPID: Structural Damage Data Collection and Analysis of a Recently Damaged Bridge

建议在修复完成前的4-6周内收集受损桥梁的结构数据。2013年4月1日，新罕布夏州朴茨茅斯的莎拉·朗桥被一艘473英尺长的货船撞上，这座桥长2804英尺，是一座双层桁架桥。经过目测和评估，确定主要结构损坏是227英尺长的钢桁架段中的两个构件严重弯曲，必须更换。这座桥在维修完成之前不能通车。新汉普郡交通部估计维修费用为250万美元，需要4-6周时间。考虑到碰撞是一种罕见的、意想不到的事件，而且可以用来收集损坏桥梁上易腐烂的振动数据的时间很短，拟议的工作符合RAPID的目标。项目组将在大桥上部署无线传感器，并记录维修前后的环境振动。此外，还将记录和分析桥梁受损的结构构件。建议的测量将提供主要结构在受损(修复前)和健康(修复后)状态下的罕见数据集，这将有助于了解受损桁架的结构行为。将分析和比较桥梁在健康和损伤状态下的振动数据，以确定固有频率的变化。此外，还将利用桥梁数据建立桥梁桁架的有限元分析模型。分析模型将用于了解桁架的结构振动特性，并可以假设桁架的频率将如何随着其他受损构件的变化而变化。这项工作将回答振动频率随不同程度损伤而变化的问题，最终有助于结构健康监测领域。

It is proposed to collect structural data of a damaged bridge in the next 4-6 weeks before repair is completed. The Sarah Long Bridge, a 2804-foot double deck truss bridge, in Portsmouth, New Hampshire, was struck by a 473-foot cargo ship on April 1, 2013. After visual inspection and assessment, it was determined that the primary structural damage is the severely bending of two members of the 227-foot segment of the steel truss and they must be replaced. The bridge is closed to traffic till the repairs are completed. The New Hampshire Department of Transportation estimates the repair to cost $2.5 million and take 4-6 weeks. The proposed work fits RAPID's goal given that the collision is a rare, unanticipated event and the short time period available to collect perishable vibration data on the damaged bridge. The project team will deploy wireless sensors on the bridge and record ambient vibrations before and after the repairs. Additionally, the damaged structural members of the bridge will be documented and analyzed. The proposed measurements will provide rare data sets of a major structure at its damaged (pre-repair) and healthy (post-repair) states, which will help understand structural behavior of a damaged truss. The vibration data of the bridge at its healthy and damaged states will be analyzed and compared to identify changes in natural frequencies. In addition, the bridge data will also be used to develop a finite element analytical model of the bridge truss. The analytical model will be used to understand structural vibration characteristics of the truss and can postulate how frequencies of the truss will change with other damaged members. This exercise will answer the question of change in vibration frequencies with different levels of damage; and ultimately help in structural health monitoring field.