中、下承式拱桥悬吊桥面系强健性设计理论与计算方法研究

The suspended floor system of half-through and through arch bridges will usually collapse due to hanger rupture, sometimes it even resulted in a fatal car crash. Therefore, it is very necessary to carry out research on its robustness design theory and calculation method. This study will introduce safety limit state into the robustness design of suspended floor system of half-through and through arch bridges, establish the robustness design principles based on reliability theory with considering the hanger rupture. Then reveal the dynamic response of the remained structures in the process of hanger rupture by means of experimental research, theoretical analysis and numerical simulation, moreover, carry out parametric study of the hanger rupture failure as well as its resulting behaviors of the rest structures. This study will propose static and dynamic calculation methods for remained structures after hanger rupture, and calculation method for suspended floor system with considering the process of hanger rupture. The robust structure measures for suspended floor system will also studied in this research, then puts forward robustness design method for suspended floor system, gives suggestion for engineering design and related code provisions. The research results will provide the theoretical foundation and technical support for the robustness design of the suspension deck system of the half-through and through arch bridges, to be applied in new bridge design and existed bridge exhibitions and strengthening, to avoid disproportionate and serious accidents that involving beams falling-off after certain local member destroying, such as hanger rupture. The research results enable to promote the development of robustness design theory in bridge engineering and can have a broad application prospect in China.

中、下承式拱桥悬吊桥面系强健性不足是造成断索后桥面与横梁垮塌甚至车毁人亡严重事故的主要原因，非常有必要开展其强健性设计理论与计算方法研究。本项目在中、下承式拱桥悬吊桥面系设计中，引入破坏安全极限状态，建立基于可靠度理论的考虑吊索破断的强健性设计原则；以试验研究、理论分析和数值模拟为手段，揭示断索过程剩余结构的动力响应机理，开展断索过程及断索后剩余结构的动力响应参数影响分析；建立断索后剩余结构的动力与静力计算方法，建立考虑断索过程的悬吊桥面系计算方法；进行悬吊桥面系强健性构造措施研究，提出悬吊桥面系强健性设计方法，提出工程结构设计与规范条文编写与修订的建议。研究成果将为中、下承式拱桥悬吊桥面系强健性设计提供理论基础与技术支撑，可用于新建桥梁设计和既有桥梁加固改造，以确保断索等局部构件破坏时不引发落梁等不成比例的严重事故的发生，促进我国桥梁工程强健性设计理论的发展，研究成果具有广阔的应用前景。

中、下承式拱桥悬吊桥面系强健性不足是造成断索后桥面与横梁垮塌甚至车毁人亡严重事故的主要原因，目前规范尚未提供相应的计算理论与方法，非常有必要开展其强健性设计理论与计算方法研究。. 本项目开展了中、下承式拱桥悬吊桥面系调查与分析，提出中、下承式拱桥悬吊桥面系强健性设计的破坏安全极限状态，对吊杆断裂状态下荷载类型及其组合系数、材料强度取值等展开分析，建立了悬吊桥面系强健性设计原则；开展了中、下承式拱桥吊索破断模型试验研究，构建了中下承式与拱梁组合钢管混凝土标准拱桥，进行了断索过程中、下承式与拱肋组合标准拱桥剩余结构动力响应分析及参数分析，揭示断索过程剩余结构的动力响应机理，引入动力系数，建立了考虑吊索破断动力影响的等效静力计算方法；开展了考虑断索冲击的悬吊桥面系强健性试验与有限元研究，提出将以横梁受力为主的悬吊桥面系空间结构体系简化为弹性支承连续梁模型进行强健性设计计算，提出了弹性支承连续梁简化计算模型的恒载、活载和吊杆冲击力的取值与布载准则；开展了悬吊桥面系强健性连接构造的局部模型试验研究，探讨了连接构造的受力特性、传力机理、承载能力和破坏模式，对影响连接构造受力性能的主要因素进行了参数分析，进行了连接构造优化设计；最终建立了中、下承式拱桥悬吊桥面系强健性成套设计计算方法，提出了工程结构设计与规范条文编写与修订的建议。. 本项目研究成果将为中、下承式拱桥悬吊桥面系强健性设计提供理论基础与技术支撑，可用于新建桥梁设计和既有桥梁加固改造，以确保断索等局部构件破坏时不引发落梁等不成比例的严重事故的发生，促进我国桥梁工程强健性设计理论的发展，研究成果具有广阔的应用前景。