Ultimate Load Capacity Analysis of a Long-Span Rigid-Frame with a Flexible Concrete Filled Steel Tubular Arch Bridge

摘要

On the basis of the virtual work principles and nonlinear finite element theory, the author introduce a plausible method, which analyse the double nonlinear problem of structure by importing the elastic-plastic constitutive relationship matrix into geometric nonlinear FEA equation. For ultimate load capacity problem, a series of concepts, such as the first kind of stability, the second kind of stability and the strength damage problem are summarized and compared. The three-dimensional finite element model for a long-span rigid-framed flexible CFST arch bridge in YiWan railway is established in three different modes, which are back bone model, space beam gird model and solid model. Considering geometric and material nonlinear, the ultimate load capacity of CFST arch bridge at usage is analyzed. Under the background of YiChang Yangtse Bridge, the catholicity method to compute the ultimate capacity is brought forward. The results show that material nonlinear is more important than geometric nonlinear in ultimate capacity analysis. The elastic-plasticity stability can be improved remarkably to reinforce the arch rib and compose plane in the foot of the arch.