Simulation Of Bond Stress In Short Cfst Column With Dumbbell-Shaped Section

In this thesis , the application status and perspective of concrete-filled steel tube(CFST) are firstly introduced briefly, as well as its structural types, mechanical characters and engineering application. Consequently, the application of nonlinear finite element contact theory in simulating of CFST is presented. Then, the thesis put forward the author's research.Although the study about bond stress in circular CFST section has become mature, the bond stress in dumbbell-shaped CFST section, a commonly used section in CFST arch bridges, is even unfamiliar, so are the value of bond stress, the mechanical state and the distribution of main stress in CFST under both axial compression and small eccentricity. To get known of the complex mechanical state of CFST component, and the round bond stress between steel tube and core concrete, this thesis firstly perform an analysis on the value and distribution of bond stress in short column with dumbbell-shaped section with finite element method (FEM). Meanwhile, further study on the influence of concrete standard and steel ratio on bond stress is carried out, acquiring mechanical properties of core concrete, such as the stress distribution, which offers important reference for design and further analysis about the column. Secondly, simulating of the contact process between concrete and steel tube surface is carried out with nonlinear finite element contact theory, acquiring the distribution of contact stress and the distribution of stress in dumbbell-shaped CFST under contact. Lastly, an actual arch bridge with dumbbell-shaped CFST is analyzed from global and local aspect, finite element methods of global analysis and local one are put forward. Through the simulating of arch rib joints, the failure coefficient of joints in destruction under normal service order is obtained.