The Cable Force Optimization And The Seismic Analysis Of The Beam Arch Combination Structure

With the social development and progress, especially some new technologies applied tosome areas in recent years, the CFST Arch Bridge occupies an increasingly important role inthe construction of the bridge. The beam arch combination structure, have excellent ability toleap, good mechanical characteristics, and broad applicability of the foundation，to becomeone of the most competitive bridges. Although this bridge style combines the advantages ofbeam bridge and arch bridge, there were also some new issues, such as the cable forceoptimization and the seismic analysis of the beam arch combination structure, need to studyby the majority of scientists.The engineering background of this paper is Nianchu river bridge. For the seismicanalysis and the suspender force of construction stage and finished stage of the beam archcombination structure, the research will include the following aspects:1. The paper recall the development of the early stone arch bridge, the steel truss archbridge, concrete arch bridge, CFST arch bridge and so on. The paper reviewed the researchstatus of CFST arch bridge, especially the research of the suspender force and the seismicanalysis of CFST arch bridge.2. Identifies the reasonable suspender force of the finished stage. First, describes threecommonly used to determine a reasonable suspender force of the finished stage——rigidlysupported continous girder, least bending energy method and rigid suspender method; Then,Use these three methods to determine the reasonable suspender force of Nianchu river bridge;Last, on the basis of its merits of the analysis, choose the reasonable suspender force theminimum bending energy method calculated.3. Identify the reasonable suspender force of the construction stage. On the basis of thereasonable suspender force of the finished stage, the paper determined the suspender tensionof the construction phase through the one-time tensioning analysis and the two-timetensioning analysis. The one-time tensioning analysis use the unknown load factors functionconsidered the construction phase to determine the reasonable suspender force of theconstruction stage. First, In the analysis software, the suspender force of the constructionstage is the unit pulling force. Then, run the construction stage analysis. And in the post-CSstage, set the constraint condition and get the unknown load factors; Last, identify thereasonable suspender force of the construction stage.4. On the basis of the reasonable suspender force of the beam arch combination structure,use the Midas/CIVIL to take seismic analysis. First, the vibration modes and frequencies of the structure were obtained by the dynamic analysis. Then, on the basis of the dynamicanalysis, take the response spectrum analysis and the time-history analysis.