Nonlinear Stability Analysis Of Concrete-filled Steel Tubular Truss Arch Bridge

Owing to the special characteristic,the reinforced and prestressed truss arch bridges were widely used in engineering practice during the 1980s~1990s.However,there exist nonnegligible structural diseases in some existing bridges during the process of operation and management.The author summarized the advantages and disadvantages about this structure,and some new scheme are proposed in the construction,material,component and structure aspects.This study presented a concrete-filled steel tubular truss arch bridge scheme as an alternative bridge scheme in one high grade highway of Guizhou province,and the nonlinear ultimate bearing capacity of this bridge under four different plans of hybrid aggregate concrete were studied.Furthermore,the structure behaviors of concrete-filled steel tubular truss arch bridge,which considered the coupling effect of creep,geometric and material nonlinearity were investigated.The main research work of this study is as follows:1.The influences of the volume fraction of lightweight aggregate on the mechanical properties of concrete were studied experimentally.Finally,a stress-strain model of hybrid aggregate concrete was proposed.2.Finite element model for concrete-filled steel tubular truss arch bridge were carried out by using CSBNLA and Midas Civil software respectively.The modeling method which considered the construction stage was studied,and the calculation results of those two software were compared.3.The nonlinear stability bearing capacity of concrete-filled steel tubular truss arch bridge at its service stage is calculated by considering the coupling effect of geometric nonlinearity,material nonlinearity.4.Considering the creep influence on the mechanical behavior of concrete-filled steel tubular truss arch bridge,the nonlinear stability bearing capacity of the structure is also calculated.The results show that: The application of concrete-filled steel tubular truss arch bridge is feasible,and the work presented in this study could provide reference for further engineering practice.