车撞作用下钢筋-超高性能混凝土桥墩损伤破坏机理与性能设计

普通钢筋混凝土桥墩在车辆撞击作用下易发生严重破坏，甚至完全丧失承载力引起桥梁整体倒塌，造成巨大的经济损失和人员伤亡。相对而言，超高性能混凝土具有优异的弯拉性能、变形能力、拉伸断裂能及应变率效应。本项目拟围绕钢筋-超高性能混凝土（R-UHPC）桥墩的抗车撞性能评估与设计，开展UHPC动态本构关系，以及车辆撞击作用下R-UHPC桥墩动态响应与损伤破坏的研究工作。通过系统静、动态力学性能试验，标定UHPC的动态损伤K&C模型，建立其本构参数确定方法；进行典型模型水平撞击试验与数值仿真分析，揭示车辆撞击作用下R-UHPC桥墩的损伤破坏机理，提出墩柱动态抗弯、抗剪承载力计算方法，以及失效模式判别准则；基于实车撞击工况的高精度数值仿真和参数影响分析，进一步建立R-UHPC桥墩的抗车撞性能设计方法。预期成果可为R-UHPC桥墩的抗车撞性能评估、设计和工程应用提供一定的理论基础和技术支撑。

Normal reinforced concrete bridge piers were prone to severe damage under vehicular collision. Under such circumstance, the collided bridge piers could lose their bearing capacities and further trigger overall collapse of bridge. Comparatively, ultra high performance concrete has the excellent flexural-tensile property, tensile facture energy, deformation capacity and strain-rate effect. Focusing on the vehicular impact-resistant performance evaluation and design of the reinforced-ultra high performance concrete (R-UHPC) bridge pier, this project will perform the study on the dynamic constitutive relation of UHPC, damage/failure and dynamic responses of the R-UHPC bridge pier under vehicle impact. By conducting the systematic static and dynamic mechanical properties tests, the parameters of dynamic damage K&C model will be comprehensively calibrated for the UHPC, and the algorithm for constitutive parameters will be derived. Moreover, based on the typical model lateral impact tests and numerical simulations, the damage mechanism of the R-UHPC bridge pier under vehicle impact will be revealed, the calculation methods of the dynamic shear and bending bearing capacities will be proposed, and the failure mode judging criterion of the impacted R-UHPC bridge pier will be established. Furthermore, by performing the high-fidelity numerical analysis of actual vehicle-bridge collision and parameter influencing study, the impact-resistant performance design method of the R-UHPC bridge pier will be put forward. The expected findings will provide the theoretical basis and technical support for the vehicular impact-resistant evaluation, design and engineering application of the R-UHPC bridge piers.