高架桥大悬臂预应力盖梁施工技术

Construction Technology of Large-cantilevered Prestressed Pier Caps of Viaduct

G312、G346南京龙潭港至绕越高速公路段改扩建工程预应力盖梁梁长33. 5 m,其中单侧悬臂长10. 75 m,为保证盖梁施工顺利进行,更改现有预应力张拉顺序,改变常规盖梁施工步骤,并采用有限元软件对大悬臂盖梁各施工阶段应力进行分析。通过将分析结果与监测结果进行对比可知,新的方法能保证大悬臂盖梁端部挠度变形不影响盖梁线形及断面尺寸,确保长悬臂盖梁施工质量及安全。该工程施工方法和施工过程可为同类工程项目的实施提供参考。

The length of prestressed bent cap which used in the reconstruction and extension project in the G312/G346 Longtan Harbor of Nanjing-Raoyue expressway is 33.5 m,and the unilateral cantilever is 10.75 m.In order to ensure that the construction of bent cap will be carried out smoothly,it is necessary to change the existing prestress tension sequences and conventional bent cap construction steps,and use the finite element software to analyze the stress on large-cantilever bent cap at each construction stage.Compared with the monitoring results,the new method can guarantee that the deflection deformation of large-cantilever bent cap at the end will not affect the line shape and section size of bent cap,and ensure the construction quality and safety of long-cantilever bent cap.And the technology could provide reference for the implementation of similar engineering projects.