800m级变截面钢管混凝土飞燕拱与自锚悬索组合桥研讨

Study and Discussion on 800-m Variable Cross-section Concrete Filled Steel Tube Swallow-type Arch and Self-anchored Suspension Cable Composite Bridge

针对800 m级超大跨径钢管混凝土拱桥的需求,提出了单叶双曲面状变截面钢管混凝土飞燕拱与自锚悬索的组合桥.钢管混凝土飞燕式拱桥的推力可与自锚悬索桥的拉力平衡,形成自平衡结构体系,且以拱肋结构受力为主,自锚悬索体系受力为辅,两者协同工作,优势互补;另外,由于采用了单叶双曲面状变截面钢管的四肢空间桁架拱肋结构形式,从而能减轻跨中拱肋节段结构自重,降低跨中节段施工吊装风险和难度,增加拱脚处截面尺寸,使得拱桥结构的质量中心和刚度中心有效降低,增加了组合桥的稳定性.将组合桥这一结构形式应用于实际工程中,进行工程参数设计,并根据建立的Midas有限元模型进行内力分析计算、模态分析和屈曲分析,验证了该结构技术措施的优越性.

In view of the demand of 800-m oversized span concrete filled steel tube(CFST)arch bridge,the composite bridge of single-plane double-curved variable cross-section CFST swallow-type arch and self-anchored suspension cable is proposed.The thrust of swallow-type CFST arch bridge and the tension of self-anchored suspension bridge are balanced,which forms a self-balanced structure system.The arch rib structure is the main force,and the self-anchored suspension cable system is the auxiliary force.The both work cooperatively and complement to each other.In addition,using the four-limb spatial truss arch rib structure with the single-plane double-curved variable cross-section CFST,the self-weight of arch rib segment in mid span is reduced,the risk and difficulty of mid-span segment hoisting construction are reduced,and the section size at the arch foot is increased so as to effectively reduce the mass center and stiffness center of the arch bridge structure,and to increase the stability of the composite bridge.This structural type of composite bridge is applied in the actual projects to carry out the engineering parameter design.Based on the established Midas finite element model,the internal force analysis and calculation,the modal analysis and the buckling analysis are carried out to verify the superiority of the structural technical measures.