新型大纵肋正交异性钢板—活性粉末混凝土（RPC）组合桥面板的疲劳破坏机理

Fatigue crack in deck and early damage of deck pavement have been posing formidable challenges to the development and application of orthotropic steel deck for a long time. One of the most effective ways to address the presented issues is to enhance the stiffness of the deck by introducing new-type composite deck systems. An innovative composite deck system that composed of an orthotropic steel deck with large cross-section longitudinal rib stiffened and a thin reactive powder concrete (RPC) layer is presented. The main objective of the project is to expound the fatigue deterioration mechanism of the proposed composite deck system. The following problems should to be investigated by model tests and theoretical analysis to achieve the foregoing goal. (1) The main mechanical behaviors, major fatigue mode and actual fatigue performance of the presented deck will be determined. The key influencing factors that are crucial to the fatigue properties of the structure will be explored in order to clarify its actual fatigue performance. (2) The fatigue-oriented multi-scale theoretical model will be established. The multi-scale coupling mechanism between fatigue crack of components and mechanical performance deterioration of the deck system will be expounded. (3) The practical evaluation method for structural fatigue endurance need to be developed based on the equivalent fatigue effects of key components. The investigation results of the project would lay foundations for the performance design and whole-lifetime design of the composite deck system presented herein. And the corresponding research findings will contribute to the sustainable development and technological innovation of bridge engineering.

钢桥面板疲劳开裂和桥面铺装损坏是长期困扰正交异性钢桥面板并制约其发展的两类关键技术难题，发展新型组合桥面板结构是综合解决上述问题的有效途径。本项目将新型桥面板与高性能材料有机结合，提出新型大纵肋正交异性钢板—活性粉末混凝土（RPC）组合桥面板，并通过模型实验和理论分析对其疲劳破坏机理进行深入研究。主要研究内容包括：（1）结构的力学特性和疲劳性能：确定结构的静载力学特性、主要疲劳破坏模式和实际疲劳寿命，明确其疲劳特性的关键影响因素；（2）疲劳破坏机理：建立面向疲劳研究的结构多尺度理论分析模型，揭示构件疲劳损伤与结构力学性能劣化的多尺度耦合规律；（3）结构的疲劳寿命评估：基于控制构件疲劳损伤综合效应的等效和量化，提出结构疲劳寿命的实用评估方法。研究成果可为新型大纵肋正交异性钢板—活性粉末混凝土（RPC）组合桥面板的性能设计和全寿命设计奠定基础，对于促进桥梁工程的可持续发展具有重要意义。

疲劳开裂和铺装损坏是长期制约正交异性钢桥面板可持续发展的世界性难题，发展新型组合桥面板结构是综合解决上述问题的有效途径。本项目提出了新型大纵肋正交异性钢—高性能混凝土组合桥面板结构，完成了钢筋混凝土（RC）、工程用水泥基复合材料（ECC）和超高性能混凝土（UHPC）三类结构层条件下，结构体系的优化设计、关键传力构件的静力和疲劳性能、结构体系的疲劳失效机理等理论分析和试验研究工作，取得了一系列研究成果，主要包括：1.推导了短栓钉的荷载—滑移曲线解析表达式，建立了短栓钉的抗剪承载力计算式；2.建立了高性能混凝土中短栓钉的疲劳强度曲线与疲劳劣化理论模型并确定了其实际疲劳性能；3.阐明了新型大纵肋正交异性钢—高性能混凝土组合桥面板纵桥向、横桥向两个维度的疲劳破坏模式与疲劳劣化过程，揭示了关键受力构件力学性能退化对结构疲劳性能的影响；4.建立了可考虑钢—混组合效应劣化效应的组合桥面板结构体系时变疲劳分析方法，提出了主导疲劳破坏模式演化全过程中控制构件疲劳损伤综合效应的量化方法，并据此发展了简化疲劳评估方法；5.阐明了焊接残余应力与初始制造缺陷两类关键影响因素对典型焊接构造细节疲劳抗力的劣化效应机制；6.建立了典型焊接构造细节疲劳裂纹扩展三维模拟方法，揭示了典型焊接构造细节的疲劳裂纹扩展机理；7.提出了基于主导疲劳失效模式的正交异性钢桥面板结构体系疲劳抗力评估方法，明确了其主导疲劳失效模式和结构体系的实际疲劳抗力；8.阐明了新型大纵肋正交异性钢—高性能混凝土组合桥面板关键受力构件力学性能退化与疲劳控制细节损伤演化间的相关关系，提出了考虑混凝土劣化效应的组合桥面板结构体系疲劳抗力评估方法；9.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的智能监测与评估系统。相关研究成果具有广阔的应用前景，已在包括深中通道在内的多项重大工程建设项目中得到了成功应用。