车辆对桥墩撞击作用下钢筋混凝土桥梁结构的易损性研究

随着我国公路网的不断延伸以及交通运输量的大幅增加，车辆撞击桥梁墩柱的事故时有发生。桥梁墩柱的车撞风险已引起各界的广泛关注；但作为关键环节之一，其易损性研究还处于起步阶段。.申请人前期建立了某典型卡车撞击桥墩的简化动力分析模型，并对钢筋混凝土柱进行了多次侧向冲击试验。本项目基于前期研究工作，拟采用有限元模拟和风险概率分析等方法对车辆与桥墩撞击下桥梁结构的易损性进行专门研究，并特别考虑车辆撞击力学特征以及桥梁结构整体损伤特征对易损性的影响。具体内容包括：1）分析车辆撞击的基本力学特征，建立车辆撞击需求的力学模型。2）分析钢筋混凝土桥梁损伤特征，建立基于性能的桥墩车撞承载能力的力学模型。3）分析车辆与桥梁参数的概率特征，并分别提出车辆撞击需求和桥墩车撞承载能力的概率模型，从而建立桥梁的易损性模型。本研究成果将有助于了解桥梁在车辆撞击下的安全性，并为后续建立桥梁结构的车撞风险评估体系奠定基础。

Along with the continuous extending of the highway network and the large increase in traffic volume in our country, accidents of vehicle collisions with bridge piers happened occasionally. Risk of bridge piers under vehicle collisions has aroused wide attention from all walks of life; however, as one of the key links, the fragility study is still in its infancy.. In previous work, a simplified dynamic analysis method was proposed for piers collided by a typical type of trucks; and several lateral impact tests of reinforced concrete columns were conducted. Based on these work, this project tries to investigate the fragility of bridge structures under the vehicle-pier collisions using finite element modelling, risk analysis, and other methods; and the effects on the fragility of the impact characteristics of vehicles and the damage characteristics of the whole bridge structures will be focused. The specific content is as follows: 1) analyzing the basic mechanical characteristics of vehicle collisions, and developing a mechanical model of the vehicle impact demand; 2) analyzing the damage characteristics of reinforced concrete bridges, and developing a performance-based mechanical model of the bearing capacity of piers under vehicle impact; 3) analyzing the probabilistic characteristics of the parameters of the impact vehicles and bridges, and proposing probabilistic models of the vehicle impact demand and the bearing capacity of piers under vehicle impact, respectively, so as to build a fragility model for bridges. The research results would help to understand the safety of bridges under vehicle collisions, and lay the foundation of setting up a risk assessment system of bridge structures under vehicle impact in the future.