Dynamic Analysis Of Concrete Filled Steel Tubular Arch Bridge

As a newly-developing bridge style, concrete filled steel tubular (CFST) arch bridge has been widely applied and rapidly developed in our country, for its own merits and can make agreement with the factual situation of bridge engineering in China. Because a large number of CFST arch bridge have been or under constructed in our country, the span of arch become larger and the bridge tends to have lighter and thinner structures. So engineers pay more attention to the dynamic behavior of anti-seismic and anti-wind, they also concern the impulse force of vehicle for the CFST arch bridge. The half-through CFST arch bridge dynamic properties were analyzed in this thesis.Neglecting the effects of shear deformation and warping, the relationship of strain and displacement for spatial arch was derived in this thesis. The Hamilton principle was used to derive the nonlinear dynamic equations of spatial arch under three-displacement-freedom and one-rotation-freedom, and the natural vibration characteristics of simplified circular arch in-plane vibration equations was analyzed. It also lays the foundation for the further study of linear or nonlinear dynamic behavior of spatial arch.Taking the example of Yajisha CFST arch bridge, the 3-D finite element model was built and the natural vibration characteristics was analyzed with the universal FEM software ANSYS. Taking into account the major parameters of arch bridge (the ratio between height vector and span, the ratio between width and span, leaning angle) and the other bridge structure (lateral structure type and hangers type), the effects of these parameters on natural vibration characteristic was studied.Applying the existing anti-seismic theory, the seismic behavior of Yajisha CFST arch bridge was analyzed by response spectrum analysis method. Basing on the results of response spectrum analysis, the axial force of arch foot serves as goal function, the leaning angle of the arch and thickness of steel tube serve as design parameters, and an optimum model might be found in the optimal design program by using ANSYS parameter design language and optimal function.