Rehabilitation of existing steel bridges by field treatment of welds

通过焊缝现场处理修复现有钢桥

• 批准号: 341305-2007
• 负责人: Walbridge, Scott
• 金额: $ 1.31万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=361167
• 关键词: Rehabilitation; existing; steel; bridges; field

A significant percentage of the cost incurred by society due to the deterioration of existing civil infrastructure can be attributed to the fatigue and corrosion of steel bridges. In many parts of the world, the deterioration of steel bridges due to fatigue is accelerated by increasing traffic volumes and vehicle weights.Post-weld treatment methods, aimed at improving fatigue performance, have been used for some time by other industries. These methods generally increase fatigue life either by modifying the weld profile and removing crack-like defects or by altering the residual stresses near the surface of the treated weld.Although their beneficial effects are widely acknowledged, concerns exist about the reliability of post-weld treatment methods, in particular under in-service (variable amplitude) loading conditions. Recent research has examined and addressed a number of these concerns. Based on this work, the main objective of the research proposed herein is to perform a number of the important steps still needed to transform post-weld treatment in the field into a viable rehabilitation alternative for existing steel bridges.Achievement of the main research objective will hinge on the development of analytical models that can reliably predict the benefit of post-weld treatment in the field under realistic, variable amplitude loading conditions. The development of such models will require a multi-faceted approach including laboratory measurements of the various possible treatment effects and fatigue tests simulating post-weld treatment in the field part way through the service life. The validated analytical models will be used to perform probabilistic assessment studies to determine the benefit of treatment for entire bridge structures.It is expected that the achievement of the main research objective will lead to significant reductions in the life-cycle costs associated with steel bridges. In addition, through the proposed research, a number of M.Sc. and Ph.D. candidates will receive training in fields expected to be highly sought after in the coming years by the government and private agencies responsible for the maintenance of infrastructure in Canada.

由于现有民用基础设施的恶化而引起的社会成本的很大一部分可归因于钢桥的疲劳和腐蚀。在世界上许多地方，由于交通量和车辆重量的增加，钢桥因疲劳而加速恶化。旨在改善疲劳性能的焊后处理方法已被其他行业使用了一段时间。这些方法通常通过改变焊缝轮廓和消除裂纹状缺陷或通过改变处理焊缝表面附近的残余应力来增加疲劳寿命。虽然它们的有益作用得到了广泛的认可，但人们对焊后处理方法的可靠性存在担忧，特别是在现役（可变振幅）加载条件下。最近的研究已经检查并解决了其中的一些问题。基于这项工作，本文提出的研究的主要目标是执行一些仍然需要的重要步骤，将现场的焊后处理转变为现有钢桥的可行修复替代方案。主要研究目标的实现将取决于分析模型的发展，这些模型能够可靠地预测在现实的可变振幅加载条件下现场焊后处理的效益。这种模型的开发将需要多方面的方法，包括各种可能的处理效果的实验室测量和疲劳试验，模拟现场焊接后处理的部分使用寿命。验证的分析模型将用于进行概率评估研究，以确定整个桥梁结构的处理效益。预计主要研究目标的实现将导致与钢桥相关的生命周期成本的显著降低。此外，通过拟议的研究，一些硕士和博士候选人将在未来几年受到政府和负责加拿大基础设施维护的私人机构的高度追捧的领域接受培训。