Research On The Key Technology Of Girder Bridge Structure Jacking

In recent years, the bridge jacking engineering are incearing. Bridge jacking is aburgeoning construction technology that is technically demanding and difficult indesign, construction and process control. This paper research on the key technologies ofin the girder bridge jacking is great significance to the safety and quality of constructionprocess.Firstly,this paper according to the continuous girder bridge, we propose thesynchronous lifting system and process applicable to it, and take the Chengdu Jiaodaoverpass jacking project as an practical example. It is mainly researched through theselection of the steel supporting bracket system, limiting system design, the choice ofthe lifting hydraulic system in the system structure and the jacking construction process.Secondly, according to the character of lifting supporting stucture，we implement thefinite element software calculation to choose the most suitable lifting support system forJiaoda overpass jacking project. Trough the analysis of the system’s safety,reasonability and economy, we propose the standardized supporting system that issuitable for multi-span continuous bridge jacking construction. Furthermore, simulationstudy has been performed to analyze the force on the beam body in the normal jackingstate, the super top state and the Jack failure state, respectively. Additionally, we discussthe content of its process monitoring design and the arrangement of the measuringpoints by the measurements of stress, displacement, crack and stability coefficient in thekey monitoring item. Finally, the feasibility and reliability of this lossless liftingreconstruction are verified according to the the national standard.It shows that the continuous beam bridge synchronous lifting system performs wellin practice. Moreover, the bearing capacity and displacement of the force components inthe lifting support system meet the standard requirements, based on the finite elementanalysis software. The eight, rather than six, steel pipes support symmetric layout ismore reasonable. Because it won’t produce additional internal force in thelifting process, which would compromise the structure security. With the presence ofboth overall and tilt displacement errors in the jacking process, the additional internalforce, tensile stress and compressive stress on the intermediate pier is much largerthan that on the abutment pier. Therefore, we need to strictly control, monitor and adjustthe intermediate pier. Monitoring results demonstrates that the beam deformation and the lifting height errors are within the warming threshold in the whole jacking process.The beam and steel pipe support the stress in good condition and there are no structuraldisease. The cap also does not have unusual settlement. The construction quality, safetyand time limit for project of the jacking all achieved the desired effect. This paper madea comprehensive and reliable analysis of the key continuous beam bridge jackingtechnology. It can provide the basis for the future design and construction for beambridge Jacking Construction Engineering. And also provided example of evidence towork out the jacking construction standard.