Study On Construction Monitoring Of A Long-span Continuous Girder Bridge Across A Railway

For medium and small span bridges,the cross-section size of pier columns is generally small.When the pier height is large and the number of pier columns is large,due to the influence of construction technology,construction equipment,natural environment and other factors,the deviation of pier columns often occurs in the construction process.Around the initial deflection of pier column,the types of pier column deflection are summarized,and the internal force distribution characteristics are analyzed.Taking a high pier continuous beam bridge with pier column deflection exceeding the limit as an example,the finite element model of the whole bridge rod structure and pier column solid structure is established,and the influence of pier column deflection exceeding the limit on the internal force,deformation and stability of main beam and pier column is analyzed.The main research work of this paper is as follows.(1)The theoretical models of deflection types and internal forces of piers are established,and the distribution rules of axial force,shear force and bending moment of piers under different deflection types are given.(2)According to the 14.6 of technical code for construction of highway bridges and culverts(JTG tf50-2011),the allowable deviation of pier perpendicularity or inclination is0.3% h and no more than 20 mm,and the result is evaluated.(3)The finite element analysis of bridge rod structure is established.The calculation of internal force of straight pier and defective pier in serviceability limit state and bearing capacity limit state,as well as the analysis of structural dynamic characteristics,overall stability and seismic performance are carried out.The boundary conditions and external forces of the pier are determined to provide the load and boundary conditions for the establishment of the solid finite element model of the pier.(4)Based on ABAQUS finite element software,the finite element modeling analysis of pier is established,and the stress changes of steel bar and concrete after pier deflection are analyzed.