钢桥面板疲劳开裂加固处治关键问题研究进展

Reinforcement and Treatment of Fatigue Cracking in Orthotropic Steel Bridge Decks:A Review

正交异性钢桥面板疲劳开裂显著影响钢桥的服役性能,其加固处治问题是工程界近年来高度关注的热点问题。对钢桥面板结构疲劳开裂加固处治的发展状况进行了分析总结,重点剖析了加固处治的关键问题和未来发展方向。结果表明:多开裂模式是钢桥面板结构疲劳问题的基本属性,加固处治方法的适用性和强化效应与开裂模式、裂纹扩展特性、裂纹长度等因素密切相关;以装配式加固处治法为代表的多类加固处治方法,通过加固件与开裂结构形成协同受力体系改变裂纹局部区域的受力特性,从而实现性能强化和延寿,加固体系中含有既有疲劳裂纹和已有一定损伤累积的未开裂模式,引入装配件或局部补强将产生新的疲劳易损部位和开裂模式,其疲劳开裂模式相较于加固前更多样、更复杂;加固前各开裂模式的损伤状态、加固体系的受力特性与开裂模式、及其剩余寿命预测等关键问题,是钢桥面板结构疲劳开裂加固处治研究的重要基础;在役钢桥面板结构的实际损伤状态评估及损伤重构方法、加固体系的剩余寿命预测和基于加固体系剩余寿命的加固设计是迫切需要解决的重要研究课题;基于功能材料的加固处治新方法和重度疲劳开裂的综合加固处治法是亟待突破的重要研究课题。

Fatigue cracking significantly affects the service performance of orthotropic steel bridge deck(OSD),making their reinforcement and treatment the focus of intense research in recent years.This paper analyzes and summarizes the development of fatigue cracking reinforcement for OSDs,focusing on key issues and future development directions.The results indicate that multiple fatigue cracking modes of the welded joints are the fundamental attributes of fatigue problems in OSDs.The applicability and effectiveness of reinforcement methods are closely related to the fatigue cracking mode and the fatigue crack length.Taking assembly reinforcement as an example,a new synergistic structure system is developed by incorporating reinforced components in existing structures.Local stress characteristics of the fatigue cracking area in the synergistic structure system is changed notably in contrast with the existing structure,thereby achieving performance enhancement and longevity.The reinforcement system contains existing fatigue cracks,cumulative fatigue damage in uncracked modes,and parts vulnerable to new fatigue generated by reinforcement.The fatigue cracking modes of the reinforcement system are diverse and complicated.Key issues such as the damage status of each cracking mode before reinforcement,the stress state of the reinforcement system,the cracking mode of the reinforcement system,and the prediction of its remaining lifetime are important foundations for studying OSD reinforcement and treatment.The assessment of the actual damage status and damage reconstruction methods for in-service OSDs,the remaining lifetime prediction of the synergistic structure system,as well as the reinforcement design based on the remaining lifetime of the reinforcement system are issues of considerable interest for fatigue cracking reinforcement in OSDs.The reinforcement method based on new materials and the treatment methods applicable to OSDs with significant fatigue cracking are important research topics that require urgent attention.