Optimization Of Core Concrete Pouring Method And Seismic Response Analysis Of Dumbbell Section CFST Arch Bridge

Since the end of the 1930 s,CFST arch bridges have been rapidly developed in many medium and large span bridges due to their aesthetically pleasing structural form,excellent structural integrity and corrosion resistance.Before the steel arch rib and the core concrete form a combined structure,the steel arch rib will inevitably generate initial stress.Different core concrete pouring methods will affect the initial stress,and will also have certain influence on the seismic performance of the arch rib structure.In this thesis,the finite element simulation analysis method is used to systematically study the core concrete pouring method of a proposed CFST arch bridge with a cross-section of 130 m.The simulation of eight different core concrete pouring methods is carried out to optimize the pouring method.The simulation analysis of two different core concrete pouring methods was carried out by response spectrum analysis method and time history analysis method,and the influence of the core concrete pouring method on the seismic performance of the CFST arch bridge structure was explored.The research work and results of this thesis are summarized as follows:1.Using the finite element software of Midas Civil to analyze the finite element model of CFST arch bridges with eight common core concrete pouring methods,the single-tube fullsection continuous pouring,first pouring the lower string tube,then pouring the upper-string tube,and finally pouring the abdominal cavity mixing method superior.According to the construction period,the appropriate increase of the partition plate for segmental pouring can reduce the initial stress of the arch rib and the vertical displacement of the arch rib;2.According to the type of seismic site where the bridge site is located and its own dynamic characteristics,the natural seismic wave is selected by the software MIDAS Building,and the natural seismic wave is modified by the software SeismoMatch.The software SeismoArdif is used to fit the artificial seismic wave according to the design response spectrum curve.The four recorded seismic wave parameters meet the seismic design requirements;3.The reaction spectrum analysis and time history analysis of two different core concrete pouring methods were carried out by Midas Civil finite element software.It was found that the time history analysis results were basically the same as the reaction spectrum analysis results.The core concrete pouring method has different seismic performance on the arch ribs.A certain influence can improve the seismic performance of the arch rib by optimizing the core concrete pouring method;4.Through the analysis of the force,displacement and stress in the critical section,it can be found that the seismic action has a great influence on the cross section of the arch,and reasonable structural measures should be taken to strengthen the arch;and the response spectrum analysis and time history analysis show a large lateral displacement.The lateral stiffness of the bridge is small.In the design,the lateral stiffness of the bridge should be increased by increasing the cross-section size,increasing the number of cross braces and reducing the spacing of the cross braces.The research work in this thesis can provide reference for the design of similar dumbbellshaped CFST arch bridges,and can also provide guidance for the subsequent construction drawings design of this bridge.