| CFST Arch Bridge has many advantages,such as good mechanical properties,convenient construction,high economic efficiency,unique shape and so on.It has been widely used and developed in China nearly 30 years.For the Long-span CFST Arch Bridge,its wide-span ratio is smaller and the lateral stiffness is weaker,thus the stability problem is more prominent,so it has important theoretical and practical value for the analysis of the stability ultimate bearing capacity under the construction stage and the completion state.This paper discusses mechanical properties of CFST and the relative theory of ultimate bearing capacity of arch bridge.The finite element calculation model of Hejiang Yangtze River bridge is established by Midas/civil 2017 program,and the ultimate bearing capacity of 500-meter CFST Arch Bridge in construction stage and completion state are carried out.The main research contents are as follows:Firstly,the first type of stability safety factor and the instability mode are obtained through the elastic buckling analysis,and the stable safety factor of the structure,which is counted into the geometrical nonlinear effect,the material nonlinear effect and the double nonlinear effect is obtained by nonlinear analysis,and the four kinds of stability safety factors are compared and analyzed.Secondly,the plastic hinge method is used to study the position and order of plastic hinge in the whole process of concrete filled steel tubular arch structure.According to the position and order of the hinge,optimizing the section arrangement of concrete-filled steel tube,so that the distribution of plastic hinge is uniform in the process of ultimate bearing capacity analysis and the ultimate bearing capacity is improved.At last,the influence of concrete strength,steel tube strength,steel ratio,the number and arrangement of transverse braces and the arch-axle coefficient on the ultimate bearing capacity of CFST arch structure are studied by using the control variable method. |
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