双向受力状态下混凝土干接缝键齿剪切破坏机理及疲劳性能研究

In this paper, the key local structure of precast segmental concrete bridge structure, which is composed of external prestressing force and dry joint, is studied. Under the action of static and fatigue test load, the shear load displacement relationship, stress distribution, shear expansion displacement of dry joint key teeth are measured. Based on the fracture mechanics and truss model, the fracture mechanics model of dry joint tooth is presented, with the extrapolation and interpolation analysis of the experimental parameters with the experimental results. Considering the dry joint key tooth shear stiffness degradation in fatigue loading, tooth damage evaluation model is proposed based on two parameter Weibull model. Based on the Paris equation, the S-N curve for the development of the main failure crack of the key tooth is presented. The completion of the project is to provide experimental data for the study of the two-way dry joint key teeth, and to provide a scientific theoretical basis for revising the relevant norms of the United States and Europe, and formulating the design code of China. The expected results are of scientific significance and application prospect, and promote the application of precast segmental concrete bridge structure with external prestressing and dry joint.

项目针对体外预应力和干接缝相结合的预制节段混凝土桥梁结构的关键局部构造，双向受力干接缝键齿的剪切破坏机理与疲劳性能进行研究。在静力和疲劳试验荷载作用下，测试干接缝键齿剪切荷载位移关系、应力分布、剪胀位移，观察裂缝形态、裂缝发展，获得开裂荷载和破坏荷载。用实验结果校准后计算模型进行实验参数的外推与内插分析。提出基于断裂力学与桁架模式的干接缝键齿的裂缝力学模型，描述干接缝的键齿剪切破坏机理。考虑干接缝键齿剪切刚度在疲劳荷载作用的退化，基于两参数威布尔模型提出键齿损伤评价模型。给出基于Paris方程的键齿主破坏裂缝发展理论S-N曲线，探明键齿疲劳破坏的演化机理。项目的完成为双向受力干接缝键齿研究提供实验数据，为修订已有欧美相关规范、制定我国的设计规范提供科学的理论依据。推进体外预应力和干接缝相结合的预制节段混凝土桥梁结构的应用。预期成果既有科学意义，又有应用前景。

项目针对体外预应力和干接缝相结合的预制节段混凝土桥梁结构的关键局部构造，双向受 力干接缝键齿的剪切破坏机理与疲劳性能进行研究。在静力和疲劳试验荷载作用下，测试干接 缝键齿剪切荷载位移关系、应力分布、剪胀位移，观察裂缝形态、裂缝发展，获得开裂荷载和 破坏荷载。用实验结果校准后计算模型进行实验参数的外推与内插分析。提出基于断裂力学与 桁架模式的干接缝键齿的裂缝力学模型，描述干接缝的键齿剪切破坏机理。考虑干接缝键齿剪 切刚度在疲劳荷载作用的退化，基于两参数威布尔模型提出键齿损伤评价模型。给出基于Pari s方程的键齿主破坏裂缝发展理论S-N曲线，探明键齿疲劳破坏的演化机理。项目的完成为双向 受力干接缝键齿研究提供实验数据，为修订已有欧美相关规范、制定我国的设计规范提供科学 的理论依据。推进体外预应力和干接缝相结合的预制节段混凝土桥梁结构的应用。预期成果既 有科学意义，又有应用前景。