Abstract：Under the guide of the existent arch bridge stability theory, the three dimension finite element model has been built for the 136m span tied-arch bridge of railway concrete-filled steel tube about the main bridge of Gechougou bridge. Its stability factor and the instability mode are given under the specific load condition. The results suggest that the structural buckling is mainly shown by out-plane buckling of the arch; elastic buckling coefficients are greater than the general requirement (4～5), which satisfies the requirement of the bridge elastic stability. Considering the nonlinear effects, after the arch ribs are progressively loaded, the ultimate loads of the arch ribs are obtained, and the vertical and transverse displacement of each controlling section when the arch ribs reach the ultimate loads. The effect of material nonlinearity on the stability of the bridge is greater than the geometric nonlinearity by comparing. According to lots of computing data, the effects of transverse brace layout, arch rib inclination angle and ratio of height to span to the stability of this bridge are revealed.
2011, Vol. 30 
