Study On Construction Control And Shrinkage Creep Effect Of Asymmetric Continuous Beam

One belt,one road,and other new strategic background of the new era in China in recent years,bridge construction will be built in large scale in deep mountains,canyons,rivers and coastal areas.With the development and improvement of expressways and railways,asymmetric span continuous girder bridges have been widely applied and developed.There is linear mutation in some positions,which makes it difficult to control the construction.Considering the shrinkage and creep effect of concrete,the secondary internal force of the structure and the deflection deformation of the bridge in the later stage will increase continuously.Even some prestressed concrete bridges have cracks in the beam concrete,which reduces the safety factor of the bridge structure and affects the normal use of the bridge.Therefore,asymmetric continuous beam bridge has important research significance.Based on the(50 + 150 + 100)m asymmetric continuous beam of South to North Water Diversion Project,this paper summarizes the existing research results of asymmetric continuous beam bridge at home and abroad,and studies the construction control and shrinkage and creep effect of asymmetric continuous beam,and the following conclusions are obtained:(1)Using finite element analysis software MIDAS / civil In 2019,the main girder of the main canal bridge across the south to North Water Diversion Project is analyzed by finite element simulation in each construction and operation stage.The internal force and deformation of the main girder in each construction stage of the asymmetric continuous bridge are studied,which provides a theoretical basis for the construction control.The adaptive control theory is used to monitor the construction of the bridge,and the sensitivity analysis and correction of the main design parameters are carried out The theoretical data analysis shows that the monitoring results are good;(2)This paper expounds the basic concept of concrete shrinkage and creep,and summarizes the factors affecting the shrinkage and creep.Taking(50 + 150 + 100)m asymmetric continuous beam as the engineering background,the shrinkage and creep model in highway bridge design code is selected to simulate the bridge,and the influence of shrinkage and creep effect on the main parameters of asymmetric continuous beam bridge,such as deflection deformation,stress and prestress loss,is analyzed;(3)This paper analyzes the influence of concrete shrinkage,creep and the loss of post prestress on the post creep deformation of asymmetric continuous bridge during operation,and sums up several optimization measures and suggestions for controlling the post creep deformation and bending moment secondary internal force of bridge from two aspects of bridge construction and design.