Probabilistic Fatigue Life Prediction and Risk Assessment of Aging Bridges in Cold Regions

该奖项的研究目标是为寒冷地区的老化桥梁开发一种创新的寿命预测和风险评估方法。详细的疲劳机制建模、除冰盐的腐蚀环境影响以及先进的概率方法将被系统地整合到一个总体框架中。本项目将考虑一般多轴随机荷载作用下的疲劳损伤累积行为，以反映桥梁的实际使用状况。寒区钢桥的腐蚀损伤扩展和疲劳裂纹扩展耦合分析将用于研究寒区钢桥的损伤相互作用。将使用随机过程理论和贝叶斯方法进行严格的不确定性量化和传播分析。将采用有效的概率方法来求解考虑力学和腐蚀损伤累积的桥梁时变可靠性问题。如果研究成功，将有助于深入了解寒区老化桥梁的多物理场损伤耦合。所开发的方法具有足够的通用性，不仅有利于桥梁分析，也有利于其他类型的结构，如汽车、飞机等的长期耐久性评估。提出了一个系统的多层次的教育计划，以提高本科教育、研究生研究和学生的课外活动。研究方法、工具和结果将被记录下来，并用于加强本科和研究生课程。预计该研究的成功将大大提高寒区钢桥的设计、分析和评价。该项目培养的学生将在老化桥梁风险管理中发挥重要作用，因为他们中的许多人毕业后将成为寒冷地区的土木工程师和政府雇员。

The research objective of this award is to develop an innovative life prediction and risk assessment methodology for aging bridges in cold regions. The detailed fatigue mechanism modeling, corrosive environmental effects due to deicing salts, and advanced probabilistic methods will be systematically integrated into a general framework. Fatigue damage accumulation behavior under general multiaxial random loading will be considered in this project to represent the realistic service conditions of bridges. Coupled corrosion damage growth and fatigue crack growth analysis will be used to investigate the damage interaction of steel bridges in cold regions. A rigorous uncertainty quantification and propagation analysis will be performed using random process theory and Bayesian methodology. Efficient probabilistic methods will be employed to solve the time-dependent reliability problem of bridges considering mechanical and corrosive damage accumulation. If successful, this research will result in a detailed understanding of multi-physics damage coupling of aging bridges in cold regions. The developed methodology is general enough and will not only benefit the bridge analysis, but also benefit other types of structures, such as automobiles, aircrafts, etc. for their long term durability evaluation. A systematic multi-level educational plan is proposed to improve the undergraduate education, graduate research, and student extracurricular activities. The research methodology, tools, and results will be documented and used to enhance both undergraduate and graduate curriculum. It is expected that the success of the proposed study will significantly enhance the design, analysis and evaluation of steel bridges in cold regions. Students trained in the proposed project will play important roles in the risk management of aging bridges as many of them will be civil engineers and government employees in cold regions after their graduation.