Research On Suspension Casting Technology Of Rigid Frame-Continuous Girder Main Beam Crossing Cold Season

Cantilever casting method is one of the most commonly used construction methods in bridge construction nowadays.It is widely used in continuous beam bridge,continuous rigid frame bridge,cable-stayed bridge and concrete arch bridge.The long-span rigid frame continuous girder bridge located in the cold region will inevitably span the cold season.The cold environment will inevitably affect the displacement and stress of the main girder in the construction and completion stages of the bridge.Therefore,in this paper,combined with a long-span rigid-frame-continuous beam bridge,the numerical analysis method is used to study the cantilever casting technology of the main girder of rigid-frame-continuous beam bridge across the cold season.(1)According to the environmental characteristics of the bridge site,according to the basic theory of concrete hydration heat temperature field and stress field,MIDAS/FEA is used to simulate the hydration heat of two sections of box girder,to study the distribution of temperature field inside the box girder,and to analyze the influence of cement varieties,cement dosage and concrete injection temperature on the hydration heat temperature field in cold environment.The stress variation of single T structure during construction stage under the action of cold wave is studied.MIDAS/CIVIL is used to analyze the deformation and stress changes during construction under the action of temperature gradient in cold region.Based on the above calculation results,corresponding construction suggestions are put forward.(2)Combining with the project of Jinmont Bridge on the Yellow River,a finite element model is established by using MIDAS/CIVIL to simulate the process of crossing the cold environment,analyze the influence of crossing the cold season on the single T structure of the bridge construction stage and the stress after completion of the bridge,and study the influence of different closure temperatures and Bridge stoppage on the alignment and stress of the bridge structure,optimize the model to provide reference for bridge construction.Opinion.(3)On the basis of summing up the construction experience of long-span bridges in cold regions in China,according to the research results in this paper,the construction suggestions of Rigid-Frame continuous girder bridges in severe cold season environment are put forward,including construction preparation,concrete transportation,pouring and maintenance,temperature monitoring,attention points of thermal insulation in cold season,bridge construction cycle analysis and non-design closure temperature closure technology.