Stress And Parameter Analysis Of Key Parts Of Special-shaped Beam Arch Composite Bridge

The half through special-shaped beam arch composite bridge is a derivative of the beam arch composite system bridge.The beam arch composite system bridge has the advantages of strong span capacity of the arch bridge and low requirements for the foundation of the beam bridge.At the same time,the thrust of the arch bridge and the axial force of the beam bridge can balance each other,and the structure is well stressed.The design and construction of modern beam arch composite bridge combines the concepts of beautiful appearance,reasonable stress,economic cost and integration with the local natural environment,so its shape is more and more unique and novel.However,the number of construction is relatively small at present.Based on a half through special-shaped beam arch composite bridge across the Yellow River,this paper studies its static mechanical properties and stability under complex conditions,and analyzes the stress and parameter sensitivity of key parts such as the beam arch joint section of V pier.The main research contents are as follows:(1)Based on the large-scale finite element program,the whole frame model of the specialshaped beam arch composite system bridge is established,and the static mechanical properties and stability of the bridge under complex conditions are analyzed.It is found that the stress and deformation of various structures of the special-shaped beam arch composite bridge under complex conditions meet the requirements of mechanical properties,and the dead load has the most obvious static impact on the structure among many influencing factors,and accounts for the largest proportion.(2)With the help of ABAQUS large-scale finite element calculation program,the refined solid models of the lower anchor plate,the upper lifting lug of the suspender,the extended arch rib segment and the V-pier beam arch joint segment are established;The stress and deformation of the lower anchor plate,the upper lifting lug and the joint of pier,beam and arch under complex conditions are analyzed.The results show that the safety reserve of stress and deformation of the upper and lower anchoring structure of the arch rib suspender is large,the stiffness of the pier beam arch joint section is large,the deformation is small,and the internal force can be effectively transmitted.(3)Through the analysis of the influence of ABAQUS path on the thickness of V-shaped pier shaft,concrete strength,inclination angle,pier shaft height and other parameter variables on the stress and deformation of the joint section,it is found that the inclination angle has the greatest influence on the stress and deformation.When the inclination angle is 70°～80°,the comprehensive stress and deformation of each path is the smallest.When the thickness of pier shaft is 400cm,the benefit is the best.The height of pier shaft can reduce the stress and increase the deformation.The influence of concrete strength on the structure is 10%.(4)Based on the response surface method,the design expert test design software is used to fit the structural response surface function of a path parameter through the central composite design method.According to the sensitivity analysis of the response surface function on each path parameter,it is concluded that the thickness of the pier body is the most sensitive to the deformation of the end beam at the top connection of the V pier,and the inclination angle of the pier body is the most sensitive to the stress and deformation in the middle of the beam section.