【摘要】 贵黔高速鸭池河特大桥为主跨800m的混合梁斜拉桥,中跨为钢桁梁,边跨为预应力混凝土箱梁。该桥采用缆索吊机进行钢桁梁节段整体悬臂拼装施工,中跨钢桁梁采用自然合龙法施工。施工中,采用优化斜拉索张拉索力的方法实现合龙口姿态的调整,即对22~24号斜拉索分别按70%、60%和50%的成桥索力张拉,合龙后再补张拉,以满足合龙线形要求;对钢桁梁合龙口的间距、标高、轴线、气温和弦杆温度等进行48h连续观测,确定合龙段的合龙温度和放置温度分别为17℃和19℃,上、下游弦杆的配切长度分别为8 114mm和8 136mm;采用钢管和工字钢等临时支撑固定合龙段,以防止其运输和吊装过程中变形。该桥已完成高精度合龙,合龙后主梁线形平顺,误差满足规范要求。更多还原

【Abstract】 The Yachi River Bridge on Guiyang-Qian′xi Expressway is a hybrid girder cablestayed bridge with the main span of 800 m.The main span of the bridge is the steel truss girder while the side spans are the prestressed concrete box girders.The steel truss girder of the main span was integrally cantileveredly assembled segment by segment,using the cable carne and was finally closed,using the natural closure method.In the construction of the bridge,the method of optimizing the tensioning forces of the stay cables was used to fulfill the adjustment of the closure gap,that was,the stay cables No.22~24 were respectively tensioned to the 70%,60% and 50% of the cable forces of the completed bridge and after the truss girder was closed,the supplementary tensioning of the cables was then carried out so as to accommodate the closure alignment requirement.The spacing,level,axial lines,atmospheric temperatures and the chord temperatures of the closure gap were observed continuously for 48 h and the closure temperature and placement temperature of the closure segment were determined to be respectively 17°C and 19°C.The match cutting length of the chords on the upstream and downstream sides was respectively 8 114 mm and 8 136 mm.The closure segment was fixed,using the temporary supports of the steel pipes and Isteel so as to prevent deformation of the segment in the transportation and installation.The bridge presently has been closed in high accuracy.The alignment of the closed main girder is smooth and the tolerances can satisfy the relevant requirements in the codes.更多还原