The In-plane Ultimate Bearing Capacity Analysis For Arch Rib Of Rectangular Concrete-filled Steel Tubular

The rectangular concrete-filled steel tubular structure, which has significant advantagessuch as great bearing capacity, good ductility and toughness, convenient production andconstruction, great fire-resisted characteristics and economic effects, etc. In recent years ithas been widespread concerned at home and abroad. However, local bucking is more likely tooccur when the stiffened rectangular CFST arch rib are subjected to eccentric compressiveload, thus it reduces the bearing capacity of specimens, thus affect its overall performance,especially when the cross-section of its components is square or rectangular. In order toimprove the performance of such kind of composite columns, longitudinal stiffeners arewelded on the steel tubes, which are called stiffened rectangular concrete-filled stiffenedtubular arch rib in this paper.Based on earlier research results, the working mechanism of the rectangular CFST archrib is studied by finite element analysis method in this paper. The finite element method wasused in the parametric analysis in order to research its ultimate load-carrying capacity. Themain research works are listed as follows:1. The research on rectangular CFST arch rib at home and abroad was reviewed firstly.The finite element method and test program were selected for the behavior analysis ofstiffened rectangular CFST arch rib subjected to eccentric compressive load.2. The principle and constitutive relation of rectangular CFST arch rib in the finiteelement analysis were studied in detail and the suitable constitutive relation of steel and coreconcrete has been established. The paper analyzed the connection between the two differentmaterials and simulated using the appropriate interface unit. Considering geometric andmaterial nonlinearities and the eventual component model can reflect correctly the finiteelement mechanics performance of rectangular CFST. The ribs were compared with thecalculated without rib results, which verifies the superiority of the stiffened rectangular CFSTarch rib3. The effects of different design parameters, like ultimate bearing capacity calculating theories, nonlinear properties, core concrete constitutive relations, load distributions, steelgrade, concrete grade, steel ratio, arch axis line type, the ratio of height to span and thelength-height ration of arch rib on the ultimate bearing capacity are studied. The results of thisthesis provide a basic reference for the future research work and revision of the designguidance for stiffened rectangular CFST arch bridges，and comparative analysis of ultimateconcrete circular and rectangular steel tube arch rib of the bearing capacity.