岩溶地区强震作用钢管混凝土拱桥致病机理及震害评估方法研究

Based on the earthquake characteristics of Karst area which is small magnitude and high intensity, on the earthquake ground motion of Karst area, the study on mechanism of earthquake damage and assessment of the long-span Concrete-filled Steel Tube(CFST) arch bridges are very important scientific and engineering problems, and comprehensive assessment of earthquake damage is one of the key scientific problems, which is very important scientific research value and engineering significance for seismic design, preventing earthquake damage, treatment and reinforcement of these bridges. The research on the new method is very necessary because the earthquake damage assessment methods of long-span CFST arch bridges are still immature. This project will research on the characteristics of earthquake ground motion in Karst area ,reveal their destruction characteristics and determine the three- dimensional spatial parameters of the earthquake ground motion. The simplified method of dynamic and nonlinear analysis on interaction of the soil- foundation- structure will be proposed and the nonlinear finite element model of long-span CFST arch bridge for mechanism of earthquake damage will be created. Based on the strength/deformation, ductility and energy, the earthquake damage assessment methods of the members of various parts will be proposed. Combining with AHP(analytic hierarchy process) and fuzzy theory, a optimal data transmission method will be proposed, and considering structural factors, environmental factors, curing conditions, soil, foundation, arch rib, web member, suspender, crossbeam of suspender, bearing and longitudinal beam，a new method for earthquake comprehensive assessment of CFST arch bridge will be proposed, which is a new approach for the earthquake damage quantitative assessment,and some measures of earthquake damage prevention, treatment and reinforcement are provided.

基于岩溶地区"小震级高烈度"的地震特点，大跨度钢管混凝土拱桥在岩溶区地震动作用下地震灾害致病机理研究及评估工作是亟需重视的科学与工程问题，其中震害综合评估是关键科学问题之一，对这些桥梁的抗震设计及震害预防与处治加固具有重要的科学研究价值和工程意义。钢管混凝土拱桥的震害评估方法仍不成熟，有必要开展其震害综合评估新方法研究。 本项目将研究岩溶地区地震动场的特征，揭示岩溶区地震动的破坏特性、确定地震动三维空间参数；提出地基-基础-上部结构相互作用动力非线性分析简化方法，建立震害形成机理研究的非线性有限元模型；提出基于强度/变形、延性和能量的各部分构件震害评估方法，结合层次分析法和模糊理论，提出最优数据传递方法，综合考虑结构因素、环境因素、养护条件、地基、基础、拱肋弦杆、腹杆、吊杆、吊杆横梁、纵梁支座、纵梁等各部分震害，提出综合评估新方法，为其震害定量评估提供新途径，并给出震害预防与处治加固措施。

近十几年来世界范围内地震频发，对桥梁安全性构成了严重挑战，岩溶地区具有“小震级高烈度”特点，目前的抗震研究很少涉及岩溶地区，且存在诸多局限和不足，对地基地震动及其参数的研究尤其是定量研究较少，地震动作用下地震灾害致病机理和评估方法研究也不够全面和成熟，为研究岩溶地区强震作用下钢管混凝土拱桥的致病机理和震害评估方法，针对钢管混凝土拱桥力学性能特点，采用试验方法和数值仿真研究了岩溶地区地震动场的破坏特性和地震动参数；采用模型试验、理论推导和数值方法研究了钢管混凝土拱桥节点的受力机理、应力分布、破坏模式和极限承载力影响因素等，提出了钢管混凝土拱桥K形节点不同破坏模式的极限承载力计算公式；提出了地基-基础-上部结构相互作用动力非线性简化分析方法，建立了震害机理研究的非线性有限元模型，研究了考虑地基-基础-上部结构共同作用的钢管混凝土拱桥地震响应以及溶洞对钢管混凝土拱桥的影响；提出了基于强度和延性比的钢管混凝土拱桥震害评估指标，建立相应指标体系和权重体系，建立了基于模糊理论和层次分析法的钢管混凝土拱桥震害综合评估模型；提出了岩溶洞地区大跨度钢管混凝土拱桥的震害预防和处治措施，为岩溶地区大跨度钢管混凝土拱桥的抗震设计和震害预防与加固措施提供科学依据，促进岩溶地区大跨度桥梁的地震灾害致病机理和评估方法研究，保障大跨度钢管混凝土拱桥在地震作用下的安全运行。