Analysis for Stability of Concrete Filled Steel Tube Tied-arch Bridge

This paper analyzes stability of some concrete filled steel tube tied-arch bridge based on linear and nonlinear stability theories.As known from numerical simulation analysis,the calculated result of stability coefficient in consideration of both material and geometric nonlinearities is less than that only in consideration of geometric nonlinearity of bridge by 50%.The paper conducts calculation and analysis by changing cross arm forms,rise-span ratio and leaning angle,and the result indicates that the stability coefficient of bridge presents the trend of linear increase with increase of cross arms,and the setup of K and X-shaped cross arms is more favorable for improvement of stability coefficient of bridge;as the risespan ratio changes from 1 /8 to 1 /3,the stability coefficient of bridge decreases after increase,and within this range of variation the safest rise-span ratio is 1 /5;as the leaning angle of arch changes from 0° to 8°,the stability coefficient of bridge presents the trend of parabolic variation,and is maximal when the leaning angle is 6°.