埋入式H型钢桩-桥台节点受弯性能与承载力

为研究整体式桥台无缝桥中埋入式H型钢桩-桥台节点的受弯性能，通过建立节点的有限元模型，分析了桥台厚度、混凝土强度、钢桩朝向、埋深比、钢材强度和轴压比6个参数对节点受弯承载力和破坏模式的影响，并在此基础上，针对不同的破坏模式提出了节点受弯模型与承载力计算公式。研究结果表明:绕钢桩强轴弯曲的节点在埋深比小于2.0时发生桥台混凝土承压破坏，增大钢桩埋深比和混凝土强度等级可有效提高节点受弯承载力；绕钢桩强轴弯曲的节点在埋深比大于2.0时，或绕钢桩弱轴弯曲的节点在埋深比大于1.0时，发生钢桩屈服破坏，提高钢桩的钢材强度等级可提高节点受弯承载力；随着轴压比的增大，发生绕钢桩强轴屈服破坏的节点的受弯承载力明显降低，但轴压比对发生桥台混凝土承压破坏或冲切破坏的节点的受弯承载力的影响可以忽略；提出的节点受弯承载力计算方法能较为准确地预测不同破坏模式的埋入式H型钢桩-混凝土桥台节点的受弯承载力，计算值与有限元结果比值的均值和计算值与试验结果比值的均值为分别为0.981和0.941，因此，可用于该类型节点的受弯承载力计算和破坏模式分析；建议钢桩埋深不少于2.0倍桩宽与混凝土桥台厚度大于2.4倍桩宽，这样可有效避免桥台混凝土的承压破坏和桥台边缘混凝土的冲切破坏。 

Flexural performance and capacity of embedded H-shaped steel pile-abutment joint

In order to investigate the flexural performance of embedded H-shaped steel pile-abutment joint for integral abutment bridges, the finite element model of the joint was established, and the effects of abutment thickness, concrete strength, steel pile orientation, buried depth ratio, steel strength, and axial load ratio on the flexural capacity and failure mode of the joint were analyzed. Based on the parameter research, the flexural model and the calculation formulae of bearing capacity were proposed for different failure modes. Analysis results show that the joint where the moment is around the strong axis of steel pile fails as compressive failure of abutment concrete when the buried depth ratio is less than 2.0. Increasing the buried depth ratio of steel pile and the strength of concrete can effectively enhance the flexural capacity of the joint. When the buried depth ratio is more than 2.0 for the joint where the moment is around strong axis of steel pile, or the buried depth ratio is more than 1.0 for the joint where the moment is around weak axis of steel pile, the failure behaves as the yielding of steel pile. Improving the material strength of steel pile will enhance the flexural capacity of the joint. With the increase of axial load ratio, the flexural capacity of the joint failing as the yielding of steel pile around the strong axis decreases significantly. While the effect of axial load ratio on the flexural capacity of the joint behaving as compressive failure or punching failure of abutment concrete can be ignored. The method proposed for calculating the flexural capacity of the joint can predicts the flexural capacity of embedded steel pile-concrete abutment joints with different failure modes accurately, and the average ratio of calculated values to simulated values is 0.981, and the average ratio of calculated values to experimental values is 0.941. So, it can be used to predict the flexural capacity and analyze the failure mode of the joint. It is suggested that the buried depth ratio is larger than 2.0 and the thickness of abutment is greater than 2.4 times the width of pile, so that the adverse compressive failure and punching failure of abutment concrete will be avoided.