Static And Dynamic Analyses Of Long Span Steel Box And Half-through Truss Continuous Beam Bridge And Its Joint Optimization

Firstly,the application status of long-span steel truss beam bridge at home and abroad is statistically analysed,and the structural and technical characteristics of this kind bridge is summarized.Focusing on a steel box and half-through truss continuous beam bridge with span combination of(202.5+280+202.5)m,the project’s main parameters are introduced in detail.With the help of finite element software MIDAS/CIVIL,a full-bridge finite element model based on beam element is established.The internal forces and deformations of each component in key stage of construction process are calculated and analysed,support reactions under construction are checked and anti-overturning measures are proposed.Then,the internal forces,stresses and deformations of this project under the action of dead load and other six load combination are calculated and analysed in the stage of bridge operation,the strength,stability and anti-fatigue ability of truss member are cheched and the sections of main truss member are strengthened.The general finite element software ABAQUS is used to establish a fullbridge finite element model based on plate element.Load-bearing mechanism of this structure is analysed and stress state of each frame member is cheched.In order to solve the appearing of excessive stress in the main truss joint,a local finite element model is established to study the optimum structural design of truss joint,by increasing the bending radius of steel plate,strengthening the stiffener rigidity of web member and optimizing the thickness of gusset plate.Meanwhile,the full-bridge finite element model which local mesh is refined is used as reference of load application and stress calculation result checking.Lanczos method is used to calculate the natural vibration characteristics of the bridge and the response of the bridge in earthquake is analysed by using response spectrum and linear time history methods,using fullbridge finite element model based on beam element in which pile-soil interaction is considered.