Study And Practice On Technology Of Construction Control For Zhengfu(45+75+172+75+45)m Curved-String Stiffened Continuous Girder With Steel Truss

With the development of the transportation,the demand for bridges is increasing day by day.Continuous beam has become the first choice for bridge construction due to its strong spanning capacity,smooth driving and low cost.However,with the increase of bridge span,construction difficulty is also increasing.In the process of construction,many factors will affect the internal force and alignment of the bridge.Problems would be caused if those factors cannot be corrected in time.In order to make the internal force and alignment of the bridge meet the design requirements better,the bridge construction control should be implemented.This paper selects appropriate bridge construction control scheme based on the summary of the development status of bridge construction control technology at home and abroad and the construction characteristics of Zhengfu(45+75+172+75+45)m curved-string steel truss stiffened continuous beam.It analyzes the continuous beam support and temporary anchorage so as to ensure the safety of the construction process.Taking the continuous beam as the research object,the author conducts structural simulation analysis of the bridge and gets the key construction stage theory deflection value and the theory of stress after establishing the finite element model with Midas/Civil.Also,sensitivity analysis is carried out on the factors affecting the bridge linear and internal force of steel stuss installation mode,temperature,creep and shrinkage of concrete and prestress loss.Suggestions are put forward for bridge construction control according to the above study.The settlement and internal force of the bridge are measured on the spot according to the monitoring scheme,and the measured value is compared with the theoretical value to identify the parameters,adjust the laying elevation and guide the construction.Through the construction control of the bridge,the alignment and internal force of the girder of the bridge meet the relevant specifications and design requirements,in that the line shape of the bridge is smooth without large mutation.Therefore,the construction control method of this bridge has achieved a good result.