预应力FRP齿连接模壳-混凝土组合桥面板在长期荷载下的损伤机理和性能研究

Focusing on the long-term performance deficiency of bridge deck induced by corrosion and fatigue of steel reinforcement, the light-weight, high strength and corrosion resistance fiber-reinforced polymer (FRP) composites are adopted to realize high performance and longevity of bridge deck. Focusing on the low utilization efficiency of FRP and relatively weak bonding problems of conventional FRP-concrete composite bridge deck, a novel and high efficiency composite bridge deck with prestressed FRP tooth-connected form and concrete was proposed. Based on the previous static study of this kind of deck, the further long-term fatigue and creep behavior of the deck will be studied from the levels of FRP form, interface between FRP forms and FRP form-concrete, and the deck. The aim of this study is to clarify the damage mechanism and key factors under fatigue and sustained loads. Finally, based on FEM analysis with long-term behavior modelling of above three levels and correction of the FEM models, the long-term evaluation and design method of composite bridge deck will be proposed. The characteristics of current research lies in the adoption of macro-micro combined method to study the fatigue and creep damage behavior and mechanism, and the prediction and design of long-term behavior by FEM analysis based on three levels of long-term behavior models with material, interfaces and structure.

针对既有桥面板因钢筋腐蚀-疲劳等因素造成的长期性能不足问题，研究采用轻质高强耐腐蚀的纤维增强复合材料（FRP）实现桥面板的高性能和长寿命。针对传统FRP-混凝土组合桥面板中FRP材料利用率低和界面粘结较弱的问题，提出一种新型高效的预应力FRP齿连接模壳-混凝土组合桥面板形式。在前期静力性能研究基础上，拟通过FRP模壳、FRP模壳间和FRP模壳-混凝土粘结/连接界面及组合桥面板结构三层次的长期疲劳和蠕变性能研究，揭示材料、两种界面和结构在疲劳和持荷作用下的长期力学性能，阐明在疲劳和持荷作用下的损伤退化机理和控制因素。最终基于有限元模拟分析，结合三层次疲劳蠕变模型，修正/验证有限元预测模型，提出组合桥面板结构长期性能评价和设计方法。本项目特色是基于高效的组合结构形式，通过宏微观结合的方法评价疲劳蠕变性能和损伤机理，通过基于材料-界面-结构疲劳蠕变模型的有限元模拟研究结构长期性能预测和设计方法。

针对传统FRP-混凝土组合桥面板中FRP材料利用率低和界面粘结较弱的问题，本项目提出了一种新型高效的预应力FRP齿连接模壳-混凝土组合桥面板形式。为此，本项目首先揭示了用于组合桥面板结构的FRP拉挤型材的长期疲劳失效机理和寿命预测模型，同时阐明了FRP模壳-混凝土之间的粘结性能本构关系和疲劳S-N规律。以此为支撑，通过静力加载测试，研究了该桥面板的破坏模式、应力应变分布规律、界面连接可靠性等指标，证明了该桥面板在静载下的有效性和可靠性。在此基础之上，本项目开展了考虑不同荷载水平的桥面板疲劳和持荷试验，结果表明该桥面板具有优异的长期性能。同时，研究还阐明了该桥面板在长期荷载下的损伤演化机理和规律，建立了相应的寿命预测模型。此外，本项目还建立了该桥面板的三维有限元模型，正确反映了该桥面板的短长期失效规律，模拟结果与试验结果之间的一致性良好，可以为桥面板的短长期性能预测提供依据。本研究圆满完成了申请书中的既定研究目标，相关成果可为推动FRP在组合桥面板结构中的广泛应用提供必要数据和支撑。