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老化桥梁开发创新的寿命预测和风险评估方法。详细的疲劳机制建模，腐蚀环境的影响，由于除冰盐，和先进的概率方法将系统地集成到一个总体框架。本计画将考虑一般多轴随机荷载下之疲劳损伤累积行为，以代表桥梁实际使用状况。将腐蚀损伤扩展和疲劳裂纹扩展耦合分析用于研究寒冷地区钢桥的损伤交互作用。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。 有效的概率方法将被用来解决桥梁的时变可靠性问题，考虑机械和腐蚀损伤积累。如果成功，这项研究将导致在寒冷地区老化桥梁的多物理损伤耦合的详细了解。该方法具有通用性，不仅适用于桥梁结构的耐久性分析，也适用于汽车、飞机等结构的耐久性评估。从本科教育、研究生科研、学生课外活动等方面提出了多层次、系统的培养方案。研究方法，工具和结果将被记录并用于提高本科和研究生课程。预计该研究的成功将大大提高寒冷地区钢桥的设计、分析和评估。在拟议项目中培训的学生将在老化桥梁的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.