Study On Effect Of Inserting Steel Plates On Cable Force And Main Arch Alignment Of Cantilever Assembled Arch Bridge

In China,the vast majority of long-span arch bridges are constructed by cantilever assembly method,and the stress and alignment of arch ribs are closely related to the construction process.Due to the influence of manufacturing accuracy,measurement error and traditional experience,the way of steel plates padded between arch segments are often used to adjust the arch rib alignment during the construction of arch bridges,wich leads that the actual tension of the buckle cable is low and the arch rib alignment deviates from the target seriously.In recent years,around the arch bridge constructed by cantilever assembly method,relevant scholars have conducted in-depth research on the buckling force and pre-lifting value during the installation of arch segments,with great achievements.However,few researches have been carried out on the influence of inserting steel plates between arch segments on the buckling force,main arch alignment and internal force.Therefore,this paper takes a reinforced concrete arch bridge and a concrete-filled steel tube arch bridge as research objects,and carries out the following work:(1)The linear characteristics of arch bridges constructed by cantilever assembly method are analyzed,based on the geometric relationship between arch segments and the relevant principles of spatial coordinate rotation and translation,the coordinate correction formula of arch segments with padding steel plate is derived.(2)The finite element simulation method of inserting steel plates into arch segments was studied by using the finite element software of MIDAS/Civil and ANSYS,and the calculation program that can consider padding steel plate are compiled by using APDL language of ANSYS.Taking a reinforced concrete arch bridge as an example,the correctness of the theoretical derivation and program in this paper is verified by comparing the theoretical results with the measured data.(3)Calculates the buckling force and pre-lifting value under normal tangent assembling state by using "one-time tensioning method for buckling cable" and "improved influence matrix method",and compares the results obtained after inserting steel plates between arch rib segments,the influence of the position and quantity of inserted steel plates on the buckling force and the main arch line shape during construction is analyzed.(4)Aiming at the main arch ring of reinforced concrete arch bridges and CFST arch bridges,there are two commonly used cross-sectional forms: box type and truss type.According to the mechanical characteristics of box arch and truss arch,this paper explores the influence of the location and number of steel plates on the line shape and internal force of the main arch of box arch and truss arch.The results of the study show that: when the steel plates are inserted into arch segments,the cable forces and the alignment of the arch rib have a significant deviation compared by usual construction process,which will change the internal force state of the arch rib.It can be seen that steel plates should be carefully used to cushion the arch segments in suspension construction of arch bridges and the production of precision should be improved.