Study On Technology Of (72+128+72)m Prestressed Concrete Continuous Beam Bridge Construction Control

In recent years,transportation in China develops quickly and the amount of bridge increases as well.To across rivers and other lines in traffic,more prestressed concrete continuous beam bridges are required to be built and their main spans are longer and longer.That will bring higher construction technology requirements for them.The cantilever method is the main construction method to built prestressed concrete continuous beam bridges.But this construction method may make the structure generate complex quality and construction safety will be hard to assured.Therefore,it is necessary to monitor the bridge in order to ensure the bridge’s line shape and stress meet the design requirements and ensure the safety of construction.Firstly,this paper introduces the characteristics of prestressed concrete beam bridge and the significance of construction monitoring,and summarizes the development of construction monitoring technology at home and abroad.Then,taking a(72 + 128 + 72)m prestressed concrete continuous beam bridge as the engineering background,the design parameters and structure of the bridge are introduced.Combined with the engineering characteristics,the construction scheme of the 0# block temporary structure is designed.The structure form,main dimensions of each component are determined and checked to ensure the safety and stability in the process of loading.Using Midas/civil and combining with engineering practice,the finite element model is established.The definition of material,load and constraint in the modeling process is explained.The concrete pouring in each construction stage and the tensioning of prestressed steel beam are calculated and analyzed respectively,The alignment and stress calculation results can be obtained for each construction stage,which will be used as a reference for alignment and stress monitoring in the field construction.The loading tests of travelers are observed synchronnously on the field,from which this paper calculates the elastic and inelastic deformations of the travelers.The elastic deformations will contribute the correctness of girders’ elevations.The temporary structure of the bridge is reasonably designed to meet the requirements of relevant codes.The structural simulation analysis has mastered the stress and displacement changes of the main girder during construction.It provides a theoretical basis for site construction,thus ensuring safe and smooth construction.