多跨连续桥船舶撞击连续倒塌研究

The accident of the progressive collapse of multi-span continuous bridge caused by vessel collision happens occasionally, which can result in huge damage to society. In this research, the reduced scale experimental test of vessel collision with multi-span continuous bridge is conducted firstly, and comparisons between experimental results and numerical ones are made to check the validity of system technology for numerical simulation of vessel-bridge collision, the effect of self-weight of structures, prestressed reinforcement, soil structure interaction on vessel-bridge collision are investigated as well. Then the research on the whole process of progressive collapse of multi-span continuous bridge caused by vessel collision using the numerical methods is carried out according to the collision accident of JiuJiang Bridge in Guangdong Province, where the impact force and displacement of bridge structure in the course of collision, the damage characteristic of bridge components, the influence of local collapse on the remaining structure components and the overall structure are investigated, the vulnerable components of bridge structure and vulnerable positions in those components are pointed out further. At the same time, the influence of bridge superstructure, vessel collision speed and collision angle, and different impacted piers on the progressive collapse of multi-span continuous bridge are analysised. At last, the simplified numerical model is obtained by simplifying the complicate numerical model to easy the engineering application, and anti-collapse design measures to increase the redundancy of bridge structure and ductile ability of vulnerable components are proposed. The study can presents a more reasonable explanation of the progressive collapse of JiuJiang Bridge, promote the progress of the vessel-bridge collision theory, and previde valuable reference to the design and strengthening of multi-span continuous bridge against progressive collapse caused by vessel collision.

多跨连续梁桥的船撞连续倒塌事故时有发生，造成的危害巨大。本项目首先开展船撞多跨连续梁桥模型试验，对比数值模拟结果，验证船撞桥数值模拟综合技术，探讨结构自重、预应力效应、水下桩土相互作用等因素对船撞多跨连续梁的影响规律。然后依托广东九江桥船撞事故，利用数值模拟对多跨连续梁船撞连续倒塌全过程进行研究，分析倒塌过程中撞击力和结构位移变化情况，桥梁构件的破坏特点，局部构件的倒塌对其它构件和结构整体的影响，以及多跨连续梁桥船撞易损构件和构件的易损部位，同时分析桥梁上部结构、船舶击速度、角度，撞击不同的桥墩对结构连续倒塌的影响。最后为方便工程运用，对数值模拟做简化处理，探讨数值模拟简化模型；同时还研究增加多跨连续梁冗余度，增大易损构件延性能力的抗倒塌设计措施。通过本项目的研究，以期对九江桥船撞事故给出更合理的解释，并推动船撞桥理论进一步发展，为此类桥型的抗船撞连续倒塌设计和加固提供参考。

多跨连续梁桥的船撞连续倒塌事故时有发生，造成的危害巨大。较为准确地模拟此类桥梁在船撞下的倒塌破坏，并坍塌相应的破坏机理，对预防和减轻船撞带来的灾害具有重要指导意义。. 本项目结合此类桥梁结构特点和工程环境，从混凝土材料本构模型、预应力效应、构件断裂模拟、混凝土构件冲击试验、桥梁结构船撞倒塌以及桥墩防船撞设施等多层次进行了系统和前瞻性研究和和探讨。. 主要研究成果包括：对常用的混凝土低速冲击本构进行了对比，对最理想的模型进行了参数确定研究，使之便于工程应用且具有很高的精度；针对预应力构件的冲击，提出了在显示分析之前施加预应力的有效方法，并得到了相关试验验证；对基岩提出了有效的三维强度破坏准则，可以较准确预测多种岩石的多轴强度；对传统的钢筋混凝土以及多种纤维加劲的混凝土简支梁进行了冲击试验，探讨了高性能混凝土构件的冲击力学性能；对一座14跨的预应力混凝土连续梁桥的船撞倒塌进行了数值模拟，得到了与事故破坏情况基本一致的结果，揭示了此类桥型的破坏特点；对连续梁桥最关键的构件-桥墩进行了新型FRP和传统钢箱防撞船装置研究，揭示了此类防船撞装置的防撞特点。. 通过本课题研究，建立了多跨连续梁桥船撞倒塌超大规模数值模拟的数值方法，涉及的研究成果如混凝土本构参数、预应力施加方法、岩石强度准则以及防撞装置等还可以应用到结构爆炸模拟、汽车撞击等多个行业。