Applicability of effective tangent modulus method in evaluation of buckling strength of long-span cable-stayed bridges

The effective tangent modulus method was proposed to estimate the elasto-plastic bifurcated stability strength of long-span cable-stayed bridge.The present method was compared with the elasto-plastic large displacement theory by calculating the ultimate strength,buckling mode and the axial force of the girder of a cable-stayed bridge with a span of 1 400 m,and was proved to be applicable and accurate.Besides,effects of live load distribution on the ultimate strength and elasto-plastic stability characteristics of the bridge were discussed.Results for the cases under different load conditions showed that relative deviations are lower than 10%,indicating that the influence of live load distribution is very slight.The stability strength of the bridge can be precisely calculated by considering the case under full-span distributed live load.