Fatigue Assessment of Retrofitted Bridge Welds in the High Cycle Domain

最近的报告量化了桥梁所有者面临的巨额维护成本，数字从安大略省的22亿美元到美国整个桥梁存量的1400亿美元不等。为了最大限度地减少这些成本，正在开发新的翻新方法来延长桥梁的使用寿命，包括：使用疲劳性能增强焊后处理，使用纤维增强聚合物(FRP)材料加固，以及使用较轻的材料(如铝)更换桥面。在评估这些翻新方法的耐久性时，疲劳仍然是一个中心问题。为了在日常基础上安全地实施这些方法，需要进行进一步的研究，以：1)验证它们在使用中变幅(VA)负载条件下的长期性能，以及2)开发改进的预测模型，以深入了解行为并促进最佳改装规划和设计。

Recent reports have quantified the significant maintenance costs facing bridge owners, with numbers ranging from $2.2 billion for the Province of Ontario to $140 billion for the entire bridge stock in the US. In order to minimize these costs, new retrofitting methods are being developed for extending the service lives of bridges, including: the use of fatigue performance enhancing post-weld treatments, strengthening with fibre-reinforced polymer (FRP) materials, and deck replacement using lighter materials such as aluminum. In assessing the durability of these retrofitting methods, fatigue remains a central issue. For these methods to be safely implemented on a routine basis, there is a need for further research to: 1) verify their long term performance under in-service variable amplitude (VA) loading conditions, and 2) develop improved predictive models to gain insight regarding behaviour and facilitate optimal retrofit planning and design.