ECC-混凝土复合桥面板弯曲受力机理与疲劳性能研究

钢-混凝土组合梁具有自重轻、承载能力高、装配化施工程度高和经济指标好等优点，在我国基础设施建设中应用越来越广泛。本项目基于高延性水泥基复合材料（ECC）抗拉强度高、延性好、控制裂缝宽度性能优异与疲劳寿命长等优点，提出一种ECC-混凝土复合桥面板结构，以期能够改善组合梁桥面板的工作性能，促进ECC应用及桥梁工业化建造。.本项目采用模型试验、数值模拟与理论推导相结合的方法开展研究。首先，研究ECC-混凝土界面的细观行为机制，揭示界面的静力与疲劳失效机理，建立考虑疲劳损伤累计的界面本构模型；之后，研究ECC-混凝土复合桥面板的静力受弯性能，明确复合桥面板的弯曲受力机理，得到合理的设计参数范围；在此基础上，研究复合桥面板的受弯疲劳性能，得到复合桥面板抗弯刚度和承载力的退化规律，明确复合桥面板的疲劳损伤机理；最后，建立复合桥面板的抗弯计算理论与疲劳寿命评估方法，提出抗疲劳设计建议。

Steel-concrete composite beams are widely adopted in infrastructure in our country due to its light weight, high carrying capacity, high degree of assembly and excellent economic performance. Engineered Cementitious Composite (ECC) possesses high tensile strength, high ductility, excellent crack-width-control capacity, and long fatigue life, hence this study proposes an ECC-concrete composite bridge deck, which is expected to improve the service performance of composite bridge deck, subsequently promote the application of ECC and the industrial construction of bridges. .In this study, the method of model test, numerical simulation and theoretical derivation will be adopted to conduct the research. Firstly, it will study the meso-behavior mechanism of ECC-concrete interface, and reveal the static and fatigue failure mechanism of interface, and establish the interface constitutive model considering the accumulation of fatigue damage. Then, the static bending performance of ECC-concrete composite bridge deck will be investigated, the bending mechanism of composite bridge deck will be clarified, and the range of reasonable design parameters could be obtained. On this basis, the bending fatigue performance of composite bridge deck will be studied to gain the degradation law of bending stiffness and bearing capacity of composite bridge deck, as a result, the fatigue damage mechanism of composite deck can be clarified. Finally, the flexural calculation theory and fatigue life assessment method of the composite bridge deck are established, and the anti-fatigue design suggestions will be proposed.