横门西特大桥异形桥塔智能施工关键技术

Key Intelligent Construction Techniques for Unconventionally-Configured Pylon of Hengmen West Bridge

南中高速横门西特大桥主桥为(66+390+324+66+66)m独塔双索面钢箱梁斜拉桥,桥塔为宝瓶形结构,高210 m,中塔柱倾斜82.5°,塔柱断面为八边形。塔柱采用分节段施工,下塔柱采用定型钢模及木模板施工;中、上塔柱7~24号节段采用多功能一体化智能造塔平台施工;下横梁采用落地钢管支架和牛腿相结合的方式施工,与塔柱同步施工;中、上横梁采用空中牛腿支架施工,与桥塔异步施工。多功能一体化智能造塔平台配置了一体化模架系统、智能布料系统、智能养护系统、信息化智能控制系统,实现了全自动顶升、智能布料、智能养护、全过程智能监测等功能。中、上塔柱钢筋采用全断面部品化施工,采用可调节式部品化预制胎架,适应钢筋截面收分,提高部品化预制效率及精度;设置内置劲性骨架,增强部品化钢筋节段整体刚度,减小吊装过程变形;采用可调式专用吊具,实现对钢筋节段吊装姿态的高精度控制;运用BIM技术,实现变截面钢筋节段重心位置精准确定及姿态模拟。该桥桥塔采用智能施工技术,提高了施工精度、质量及效率,节约工期约60 d。

The main bridge of Hengmen West Bridge of the Nansha-Zhongshan Expressway is a steel box girder cable-stayed bridge with five spans of 66,390,324,66 and 66 m.The bridge has only one pylon which rises 210 m and carries two planes of stay cables.The two legs of the pylon incline inwardly towards each other,forming a vase-shaped structure.The pylon legs of octagonal cross-section were installed in segments,the lower leg segments were erected using shaped steel formwork and wooden formwork,and the intermediate and upper leg segments(segments No.7-No.24)were erected by the multi-functional intelligent integrated construction platform.The construction of the lower crossbeam was carried out simultaneously with the construction of the pylon legs,by the combined utilization of the floor-standing steel pipe scaffolds and corbels.The construction of the upper crossbeams was carried out using corbels,independent from the pylon legs construction.The multi-functional intelligent integrated construction platform consists of a formwork system,an intelligent feeding system,intelligent curing system,and computer-based intelligent control system,which can achieve automatic jacking,intelligent material feeding,intelligent curing and full-process intelligent control.The reinforcement in the intermediate and upper pylon leg segments were fabricated off site to the required shapes in the adjustable moulding beds which can adapt to the section of rebars,to improve the fabrication efficiency and precision.Stiffening skeletons are also installed within the pylon leg segments to improve the overall stiffness of the segments while reducing the deformation during segment hoisting and installation.The adjustable specialist riggings were used for the high-precision control of the attitudes of the reinforcement during the hoisting process.The locations of the gravity center as well as the attitudes of the reinforcement of variable cross-section were determined by using BIM technology.The utilization of intelligent construction technology led to improved construction precision,quality and efficiency,and the construction schedule was shortened by 60 days.