| As a combined material, the core concrete of concrete-filled steel material endures triaxial compressions which strengthen the material’s resistance capacity of compression and deformation. With the stability and convenience of manufacturing and installation, the concrete-filled steel tube arch bridge is developing with the tendency of becoming long-span and super-long-span arch bridge.There is sort of interaction or constraint between steel tube and concrete since the concrete is filled and sealed in the steel tube, which make this combined material different from the normal concrete material when the concrete creep occurs. Under the influence of concrete creep, stress redistribution phenomenon occurred in this combined material which leads to the stress declination of concreted and stress increment of steel tube. This paper based on the mechanism and cognition of concrete creep, has introduced and analyzed the commonly used creep mode and theory comparatively. At the background of an arch Bridge, a finite element model has been constructed in the ANSYS finite element software, and then the creep effect analysis of the main arch rib has also been implemented.Linear theory is commonly accepted in former structure calculation. With the span growth of CFST arch bridge, the nonlinear property is more evident. This paper, based on the statement of nonlinear theory and calculation method, has also taken the geometric nonlinearity analysis of CFST bridge into consideration by using the FE model in ANSYS.Considering the influence of concrete creep and geometric nonlinearity at the same time is quite rare at present. This paper which adopted the differential method and derivation of tangent stiffness matrix of plane beam element has programmed a procedure aimed at the analysis of considering creep and geometric nonlinearity coupling simultaneously with the help of initial strain method. A calculation example has been analyzed by using the program to testify its accuracy. |
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