| Large tonnage prestressed concrete box simply supported continuous beam system has been widely used in highway bridge construction in China in recent years.Large tonnage prestressed concrete box girder has good structural stability,fast on-site construction speed,smooth driving in the later operation stage,and improved passenger comfort.At present,there are few studies on the conversion technology of large tonnage prestressed concrete box simply supported continuous beam system.Taking the upper structural engineering project of Hangzhou Ningbo double track S1 bid section as an example,the technology of large tonnage prestressed concrete box simply supported continuous beam system is deeply studied.The main research achievements include:1.Referring to domestic and foreign research achievements and specifications,a suitable analysis method has been found by studying the basic theory of large-tonnage prestressed concrete box simply supported continuous beam system.The coupling effects of shear lag,torsional distortion,and bending deformation during the transformation process of large-tonnage prestressed box simply supported continuous beam system were studied.2.Established a refined finite element model,selected the optimal grid element attributes for simulation analysis,and used HYPERMESH to complete grid division for complex components;A suitable method was selected in ABAQUS to simulate the system transformation process during the construction process;Analyzed the bending deformation,stress distribution,and stress changes in each construction stage;Study and simulate the location of maximum tensile and compressive stress during construction,analyze the reasons for the occurrence of critical values,and propose solutions.3.The effect of concrete shrinkage and creep was simulated in ABAQUS.A concrete shrinkage and creep prediction model was selected to simulate the large tonnage prestressed concrete box simply supported continuous beam.The concrete shrinkage and creep subroutine was written in Fortran language,and the program was written in Python language to fit the creep coefficient.The influence of concrete shrinkage and creep within 3000 days on the transformation process of large-tonnage prestressed concrete box simply supported continuous beam system was analyzed.4.There are many key control links that need to be further studied in the construction process of the conversion of large-tonnage prestressed concrete box simply supported continuous beam system.Proposed a system transformation construction process and a construction process to ensure safe construction and reduce wet joint concrete cracking,and conducted research on the removal process of steel sand box temporary supports and other auxiliary construction equipment.The above research focuses on the conversion technology of large-tonnage prestressed concrete box simply supported continuous beam system,and proposes targeted analysis methods and techniques suitable for this system. |
