Safety Analysis Of Highway Bridge Under Asymmetric Loading

Asymmetric loading will cause certain disturbance to the soil around the bridge and change the stress of the pier and abutment foundation,which will cause bridge settlement,tilt and even structural damage.The economic loss and casualties of the country have a large negative social impact,so it is of great significance to study and analyze the impact of asymmetric loading on the safety of the bridge.The thesis is based on the asymmetric stacking safety evaluation project of a highway ramp bridge in a soft soil area,and uses the numerical simulation software ABAQUS as a research platform to carry out research.First,a 3D finite element model of the bridge,foundation soil and piled soil is established to simulate the squeezing effect of the piled soil,the deformation of the foundation soil layer,the coupling relationship between the pile and soil of the bridge,and the displacement and internal force change process of the overall structure of the bridge,to assess the safety of the bridge at this stage;then study the deformation law of the foundation soil under the influence of the pile,Discusses the impact of the difference in the dimensions of the pile on the structure of the adjacent bridge,based on the simulation of the ramp bridge under extreme asymmetric load to reach the limit state of the working conditions;Finally,according to relevant specifications,comparative analysis under the influence of asymmetric pile load and the state of safety in the form of bridge structures.The research and analysis results show that:(1)After being piled up near the ramp bridge,the bridge has a certain lateral displacement and settlement,the base bending moment increases by 177.7%,the base axial force increases by 27.3%,and the internal force of the main pier and superstructure has no significant change The characteristics of bridge pile foundation deformation,moment and lateral displacement are consistent with previous research conclusions.The bridge as a whole is still in a safe state;(2)The lateral displacement of foundation soil caused by stacking mainly occurs in weak soil layers.Under the effect of a large pile load,the bridge foundation displacement may exceed the allowable value of the specification;reduce the pile height,Increasing the stacking spacing can effectively control the deformation of the foundation soil and reduce the displacement of the bridge structure;the width of the piled soil has a significant effect on the lateral displacement of the foundation soil and has a small effect on the settlement,so clean up the nearby piled soil energy of the bridge Effectively control the flexural deformation of the pile foundation and the horizontal displacement of the bridge;(3)After the expansion joints and bearings are installed relative to the bridge with pier and beam consolidation,the bridge is prone to greater structural deformation under the influence of asymmetric loads.The amount of deformation increases,the bearing produces shear deformation along the bridge direction,and the lateral displacement of the bridge pile foundation increases slightly,and the lateral displacement of the superstructure increases significantly;the curvature of the bridge’s linear curvature and the relative position of the stacking deformation of the expansion joint The amount also has an impact.The research results have reference value for the safety assessment of similar bridges.