The Geometric Nonlinear Influence On Different Span Cable-Stayed Bridges During Construction Process

This thesis focuses on the geometric nonlinear analysis of different span cable-stayed bridges considering overall construction process.Firstly, the basic theory of geometric nonlinear analysis for cable-stayed bridge is introduced. Then three principle factors that geometric nonlinear effects of cable-stayed bridges are described, which are large displacement,cable sag effects and combined effects of bending moment and axial force; then the finite element methods are introduced separately.And then, it is briefly described that the cable-stayed bridge construction methods and the analysis methods of construction phase of the cable-stayed bridge, the structural overview and basic construction process of the project are illustrated, the models of different span cable-stayed bridges are builded and calculated respectively by the finite element software NLABS, the calculation includes linearity,part nonlinearity (only considering the sag effect) and complete nonlinearity.Finally, it is analyzed that the geometric nonlinear behavior in cantilever construction process and Full-bridge closure. From such aspects as the incremental deformation of constructing and completed structure under loads, the total structure deformation during overall process, the structure internal force, etc., the magnitude and rule of geometric nonlinear effects of long-span cable-stayed bridges are fully researched.By studying fully shows: With the growing span, the geometric nonlinear influence is becoming bigger, when the span is up to a certain length, the influence is not ignore.