Nonlinear Stability Analysis Of The Continuous Steel Box Girder

Steel box girder is widely used in the bridge construction because of the characteristics of high-strength lightweight,the stability is an important factor affecting the safety.To understand the essence of the problem of stability,not only the linear stability analysis,but also the material nonlinearity and geometric nonlinearity are take into consideration.In this paper,the nonlinear stability and linear stability by finite element software ABAQUS continuous steel box girder bridge under the condition of different stiffeners were compared and analyzed under the engineering project.To investigate the stability of continuous steel box girder nonlinear effect parameters and optimization suggestions,main work are completed in the following:(1)The domestic development situation is introduced briefly,together with the continuous steel box girder on the stability problem of research achievements and existing problems.The literature mainly focuses on the study of the linear stability problem,but these research results can provide reference to the research of nonlinear stability of continuous steel box girder.(2)By using the software ABAQUS,a finite element model of the continuous steel box girder with shell element model method,and the calculation of linear and nonlinear stability of steel box girder,to analyze the similarities and differences of the continuous steel box girder in the operation process of linear and nonlinear mechanical properties and strain state.Then the continuous steel box girder linear stability analysis is carried out by changing the form of stiffening rib,rib spacing and stiffener thickness.Then the operation stage of each order stable eigenvalues and instability modes were obtained,and the analyses of influence of stiffeners,stiffener spacing and thickness of stiffeners on the linear stability of continuous steel.(3)By considering the initial defects,material nonlinearity and geometric nonlinearity on the nonlinear stability analysis of continuous steel box girder,the operation stage of each order stability coefficient and the ultimate bearing capacity were gained,and then analyzes the types of stiffeners,stiffener spacing and stiffener thickness on the non linear stable effect of continuous steel box girder.(4)Finally the design method of rib stiffener was put out,reasonable size and optimal spacing and various stiffeners range,to provide a reasonable continuous steel box girder structure design scheme for the stability problem,and provide reference for similar bridge.(5)Shell element model is established using the finite element software Midas Civil,by changing the thickness and stiffening rib stiffener form of steel box girder for maximum design bending moment and the maximum shear analysis...