新型高性能正交异性钢桥面板的疲劳失效机理与结构体系疲劳抗力研究

Fatigue crack is one of the most pressing problems confronting conventional orthotropic steel bridge deck (OSD). Development of innovative high performance OSD, aiming to improve the fatigue performance, is the imperative demand for the sustainable development of bridge project. An innovative high performance OSD incorporating several novel structural details is proposed. Main objective of the project is to expound its fatigue failure mechanism and fatigue resistance based on the multi-scale coupling relationship between fatigue failure modes of details and structure system. At the structural detail level, the method for quantitating deterioration effects of initial manufacturing defects on the fatigue resistance of the proposed details will be developed. Probability statistic properties of fatigue resistance will be determined for each important fatigue failure mode of the proposed details. At structure system level, the relationship between the design parameters of structure system and the accumulated fatigue damage of important fatigue failure mode will be revealed. The evolution mechanism of dominating fatigue failure mode of structure system will be expounded based on the established model considering coupling relationship between fatigue damage and key influencing factors. The evaluation method for fatigue resistance of structure system will be proposed by determining the dominating fatigue failure mode of structure system on basis of the relationship between fatigue failure mode and accumulated fatigue damage of important failure modes. Investigation results of the project will provide scientific instruction related to high performance and analysis method for the whole life cycle design theory of steel bridge, and have important significance in promoting sustainable development.

传统正交异性钢桥面板疲劳开裂问题突出，已成为制约桥梁工程可持续发展的痼疾，发展新型高性能正交异性钢桥面板是解决这一难题的有效途径。本项目研发新型构造细节并提出新型高性能正交异性钢桥面板，以构造细节与结构体系疲劳失效模式的多尺度耦合关系为切入点，对其疲劳失效机理和疲劳抗力进行深入研究。在构造细节层面，提出初始制造缺陷对于构造细节疲劳抗力劣化效应的量化方法，确定构造细节各重要疲劳失效模式对应疲劳抗力的概率统计特征；在结构体系层面，阐明结构体系设计参数对于重要疲劳失效模式疲劳致损效应的影响机制，建立疲劳致损效应与关键影响因素的耦合关系模型，揭示结构体系主导疲劳失效模式的演变机理；在此基础上由重要失效模式的疲劳抗力及其疲劳致损效应入手，提出基于主导疲劳失效模式的结构体系疲劳抗力实用评估方法。研究成果可为钢桥的全寿命周期设计理论提供高性能结构体系和分析方法支撑，对促进其可持续发展具有重要意义。

传统正交异性钢桥面板疲劳开裂问题突出，已成为制约桥梁工程可持续发展的痼疾，发展新型高性能正交异性钢桥面板是解决这一难题的有效途径。在项目资助下，研发了新型构造细节并提出新型高性能正交异性钢桥面板，以构造细节与结构体系的主导疲劳开裂模式为切入点，对其疲劳开裂机理和疲劳抗力进行系统研究，取得了系列创新研究成果，主要包括：1.提出了纵肋与横隔板新型交叉细节，并对其疲劳性能进行了系统的试验与理论研究，揭示了其疲劳开裂机理，确定了其主导开裂模式；2.发展了纵肋与顶板新型双面焊构造细节，通过系统的试验与理论研究，揭示了其疲劳开裂机理，确定了其主导开裂模式与疲劳抗力；3.建立了疲劳裂纹扩展三维模拟方法，阐明了纵肋与顶板构造细节的疲劳裂纹扩展特性与性能劣化机理；4.通过切片和扫描电子显微镜分析，确定了纵肋与顶板构造细节的焊接微裂纹尺寸和分布特征，并阐明了焊接微裂对纵肋与顶板构造细节主导开裂模式的影响；5.引入超声冲击技术强化纵肋与顶板构造细节的疲劳性能，并对其强化效应进行了量化评估；6.基于等效结构应力建立了正交异性钢桥面板结构体系疲劳抗力评估方法，实现了对钢桥面板结构多开裂模式的疲劳性能统一评估；7.基于结构体系疲劳抗力评估方法阐明了关键因素对构造细节主导开裂模式的影响机制，并确定了纵肋与顶板构造细节的临界熔透率；8.提出了新型高性能正交异性钢桥面板，通过试验与理论研究揭示了其疲劳失效机理，确定了其疲劳抗力；9.建立了疲劳可靠度评估模型，对正交异性钢桥面板结构体系的疲劳可靠度进行了评估，并量化了关键因素对疲劳寿命的影响；10.构建了疲劳损伤评估和指标可视化的正交异性钢桥面板疲劳损伤智能监测与评估系统。相关研究成果具有广阔的应用前景，已在包括深圳至中山跨江通道在内的多项重大工程建设项目中得到了成功应用。

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