【摘要】 贵黔高速鸭池河特大桥为主跨800m的钢桁-混凝土混合梁斜拉桥,中跨钢桁梁采用"N"形桁架。受地形、运输和工期等条件限制,该桥采用缆索吊机进行16m长钢桁梁节段整体悬臂拼装。施工中,在边跨增设主动张拉的背索,以抵消缆索吊机对该桥变形的影响;优化接头处高强螺栓施工的时间和顺序,以防止新节段安装时高强螺栓受剪;重视钢桁梁节段现场的预拼装、测量和误差调整工作,以确保16m长节段拼装精度;采用等值张拉法和群锚千斤顶张拉,以实现钢绞线斜拉索的索力均匀性和整体索力控制;优化斜拉索施工索力,以实现合龙口姿态的调整,采用温度自然合龙法,以实现高精度合龙。鸭池河特大桥合龙后主梁线形平顺,施工误差满足规范要求,该桥已于2016年7月建成通车。更多还原

【Abstract】 The Yachi River Bridge on Guiyang-Qian′xi Expressway is a steel truss and concrete hybrid girder cable-stayed bridge with a main span of 800 mand over the main span,the part of the steel truss girder is the N-shape truss.Restricted by the conditions of the topography,transportation and construction time schedule of the bridge,the 16 m long segments of the steel truss girder were integrally cantileveredly assembled at the site,using the cable crane.In the construction,the temporary active tensioning backstays were added to the pylons on the side spans and were used to counteract the influences of the cable crane on the deformation of the truss girder.The construction time and sequences of the high-strength bolts at the joints of the segments were optimized so as to avoid the shear in the bolts as the new segments were being assembled.The special attention was paid to the site preassembling,survey and tolerance adjustment of the segments so as to ensure the assembling accuracy of the segments.The stay cables were tensioned,using the equivalence tensioning method and the group anchor jacks,so as to achieve the uniformity of the steel strand stay cable forces and the control of the whole cable forces.The stay cable forces in the construction were optimized so as to facilitate the adjustment of the state of the closure gap.The truss girder was closed,using the temperature natural closure method,so as to close the girder in high accuracy.The final alignment of the closed truss girder of the bridge was smooth,the construction tolerance could meet the relevant requirements in the codes and the bridge was completed and open to the traffic in July,2016.更多还原