【摘要】 长沙市洪山大桥是一座无背索斜拉桥,该类型桥梁的受力特性与常规斜拉桥有较大的不同,造成其设计和施工的特殊性。归纳国内外已建和在建的无背索斜拉桥的一般情况,详细论述其塔梁平衡关系和索、塔倾角的取用准则,根据优化塔、索造价和降低塔重偏差对塔身受力的影响来可以得到塔的合理倾角。进一步介绍洪山大桥的主梁类型和截面型式、若干构造细节和施工过程,分析研究表明钢-混凝土组合脊骨梁更能够适应无背索斜拉桥的受力特点,并具有造价和技术优势;主跨两端特殊的构造设计可以保证塔梁结合部和主跨-辅助跨过渡段的传力平顺;施工中采用桥面预压工艺可以有效改善桥面板横桥向受力状态。更多还原

【Abstract】 Hongshan Bridge is a harp-shaped cable-stayed bridge without backstays,located in Changsha.The behaviors of this type of bridge are different from those of the conventional cable-stayed bridge,which make some particularity on structural details and construction method.The newly constructed and in-service cable-stayed bridges without backstays are summarized.The weight balance relationship between pylon and girder and the criterion on determining the angles of pylon and cables are expounded in detail.It is found that the suitable inclination angle of pylon can be obtained via optimizing the cost of pylon and cables and reducing the influence of the weight error on the mechanical characteristics of pylon.The structural type and cross section of the main girder,the special structural details and the construction procedure of the Hongshan Bridge are presented.It is concluded that the steel-concrete composite spine girder structure is advantageous in satisfying the mechanical characteristics of the bridge.The special structural design for the two ends of the main span can ensure smooth transfer of forces between the pylon and the girder and between the main span and the auxiliary span.Moreover,the pre-bending prestressing method is capable of effectively improving the performance of the concrete deck in the transverse direction.更多还原