Research On Dynamic Characteristics And Performance Of Load Lateral Distribution Of Box Girder Bridge With Corrugated Steel Webs

Box girder bridge with corrugated steel webs is a new type of improved composite structure bridge,which has been widely concerned in recent years.Replacing the concrete floor with the steel floor not only avoids the cracking problem in the tensile zone of the floor,but also greatly reduces the weight of the superstructure of the bridge.As a new structure,related research is still in its infancy.Therefore,in order to study the dynamic characteristics and performance of load lateral distribution of box girder bridge with corrugated steel webs,a prefabricated corrugated box girder bridge with corrugated steel webs on the connecting line of Lanzhou Jingzhong high speed airport is taken as the background,and the box girder bridge is analyzed by means of finite element simulation,field test and theoretical analysis.The main research contents are as follows:(1)In this paper,the prefabricated box girder bridge with corrugated steel webs of Jingzhong high-speed airport connecting line is tested.The dynamic test adopts pulsation method,and the environmental excitation adopts non artificial excitation method.The acceleration sensor is used to collect the vibration information of the bridge structure under ground pulsation,wind load and other factors,and the natural vibration frequency and vibration mode of the bridge are obtained,which provides reference for the comparison of existing code formulas The verification of the accuracy of the finite element model provides a reliable reference.(2)The finite element model of box girder bridge with corrugated steel webs is established by ANSYS software.The accuracy of the model is verified by the experimental data,and the correct modeling method is obtained.The natural frequency of box girder bridge with corrugated steel webs is analyzed under the influence of structural parameters such as transverse connection type,transverse connection stiffness,diaphragm spacing,bridge span,girder height,thickness of corrugated steel web,thickness of steel bottom plate and number of main beams.According to the research conclusions,the engineering suggestions are given.Then,the modified parameter τ is introduced to modify the natural frequency formula of simply supported beam bridge in the code.The modified formula reduces the error of natural frequency of box girder bridge with corrugated steel webs,and can be used to calculate the natural frequency of the bridge.(3)In this paper,the finite element model of box girder bridge with corrugated steel webs is established,and the accuracy of the model has been verified before.The natural frequency of the bridge is analyzed under the influence of bridge span,bridge height,transverse connection type between boxes,curvature radius,thickness of corrugated steel web and steel bottom plate.The parameters α and β are introduced to modify the calculation formula of bridge natural frequency given in the code.The effect of bridge span,beam height and curvature radius are considered in the modified term,and the error of calculation result is small,which can be used to calculate the natural frequency of box girder bridge with corrugated steel webs.(4)Due to the structural characteristics of box girder bridge with corrugated steel webs,torsion is inevitable when vertical bending occurs.A large number of finite element models are established by ANSYS software to analyze the influence of transverse connection type between boxes,bridge span,number of main beams and other factors on load transverse distribution coefficient of box girder bridge with corrugated steel webs.