承插式预制桥墩在车辆撞击下的损伤机理及防撞设计研究

In recent years, the socket-mounted prefabricated piers have been widely used in bridge engineering at home and abroad and show rapid growth in need as they have the advantages of low construction precision requirement, short construction period, easy quality assurance and low environmental influence comparing with the traditional integral cast-in-place piers. But researches on the former piers are far less extensive and systematic than the latter. This project intends to study the bridge dynamic response behavior, damage evolution process and failure characteristics caused by vehicle collision onto the socket-mounted prefabricated pier systematically through using a combination method of experiments, theoretical analysis and numerical simulation. Influence of the socket connection parameters including the pier embedded depth and the cushion cap opening size as well as the pier stiffness, the type and mass of vehicle, the vehicle speed and the impact angle will be analyzed systematically. Optimize the structure parameters of socket connection. Reveal the damage and failure mechanism of socket-mounted prefabricated piers. Establish the formula for calculating the vehicle impact force that can reflect the actual conditions of the bridge and vehicle. Put forward a practical method for evaluating the bridge structure damage caused by the vehicle impact. Discuss the reasonable parameters value of the encased steel plate including intensity, thickness and height on improving the pier's impact resistance. Provide theoretical support and engineering guidance for reasonable application of socket-mounted prefabricated piers in the substructure of bridge engineering.

与传统的整体现浇桥墩相比，承插式预制桥墩具有施工精度要求低、施工工期短、质量易保证、对环境影响小等优点，近年来在国内外桥梁工程中得到广泛应用并呈快速发展趋势。目前对这种桥墩的研究远没有整体现浇桥墩那样深入和系统。本项目拟通过试验、理论分析和数值模拟相结合的方法，系统地研究车辆撞击承插式预制桥墩所引起的桥梁结构的动力响应行为、损伤演化过程和破坏特征，分析桥墩插入深度、基础开口尺寸等承插式连接构造参数、桥墩刚度以及车辆类型、载重、车速、撞击角度等因素的影响规律，优化承插式连接构造参数，揭示承插式预制桥墩的损伤失效机理，建立能反映车桥实际情况的车辆撞击荷载的计算公式，提出桥墩结构受车辆撞击所致损伤的评价方法，研究采用外包钢板提高承插式预制桥墩抗撞性能时钢板的强度、厚度、高度等参数的合理取值，为承插式预制桥墩在桥梁工程下部结构中的合理应用提供理论支撑和工程指导。

随着我国交通运输事业的迅速发展，车辆等交通工具日益增加，为保证交通流顺畅和缓解交通拥堵，修建了大量的立交桥、高架桥等跨线结构物，车辆撞击桥墩的事故时有发生。与传统的整体现浇桥墩相比，承插式预制桥墩具有施工精度要求低、施工工期短、质量易保证、对环境影响小等优点，近年来在国内外桥梁工程中得到广泛应用并呈快速发展趋势。而目前对这种桥墩的研究远没有整体现浇桥墩那样深入和系统。本项目通过试验、理论分析和数值模拟相结合的方法，系统地研究了承插式预制桥墩在车辆撞击作用下的动力响应行为、损伤演化过程和破坏特征，深入分析了墩柱嵌入深度、承台基础预留承插间隙以及连接界面型式等承插式连接构造参数、桥墩自身因素以及车辆类型、载重、车速等因素的影响规律，优化承插式连接构造参数，揭示承插式预制桥墩的损伤失效机理，建立了车辆撞击荷载的计算公式，提出桥墩结构受车辆撞击所致损伤的评价方法，研究采用外包钢板提高承插式预制桥墩抗撞性能时钢板的强度、厚度等参数的合理取值。本研究成果将有助于了解承插式预制桥墩在车辆撞击作用下的安全性，在设计理论和设计方法方面为承插式预制桥墩结构的应用和发展奠定基础，为承插式预制桥墩在桥梁快速施工中的合理应用做出积极的贡献。