Stability And Effect Analysis Of Mobile Protective Scaffolding Of Railway In Operation

In this paper,based on the rotating bridge of Ningbo Metro Line 4 across the Xiaoxiang-Ningbo Railway and Hangzhou-Shenzhen High-speed Railway,the existing mobile protective scaffolds below the project as the basis,in-depth study of the protective effect of mobile protective scaffolds in the protection process,the main research contents and results are as follows:(1)Theoretical calculation and analysis of mechanical protection effect of mobile protective scaffolding.Will move set-up for protection by space structure model into 2d plane rigid frame stress,mobile set-up for protection under the action of the different load combination of stress,deflection,stability analysis have been deduced formula,and on the basis of the set-up for mobile protective formula deduction,an increase in the model the scaffolding Angle and shearing stress formula is deduced;When the basic wind pressure value is 0.6kN/m2,the mobile protective scaffold is in the safe protection state under the design load.When the basic wind pressure value is 1.3kN/m2,and the concentrated load acts on the center or 1/3 of the main girder,the deflection value of the mobile protective scaffold under the action of partial load combination exceeds the allowable deflection value,and the mobile protective scaffold is damaged.According to the theoretical calculation,the maximum concentrated load that the mobile protective scaffold can bear is 86.69 kN.(2)Analysis and study on indoor model test of mobile protective scaffolding.The indoor model was designed according to the 1:15 similarity ratio,and the similarity relationship between the mobile protective scaffold and the model scaffold was deduced through the equation analysis method,and the similarity constant was determined.The stress,deflection,stability,rotation Angle and shear stress of the model scaffold are calculated and analyzed by theoretical calculation,which provides theoretical guidance for model test.Through laboratory tests,the stress,deflection,stability,rotation Angle and shear stress of the model scaffold under different load conditions were sorted out and analyzed.Compared with the theoretical adjustment results,the theoretical stress and shear stress are close to the experimental data,which preliminarily proves that the analysis by the two methods is reasonable.(3)Numerical simulation study on the effect of moving protective scaffolding.Combined with the theoretical research,numerical simulation analysis of no ceiling mobile set-up for protection under different load combination of structural strength,stiffness and overall stability,mobile protective scaffolding structure damage analysis results and the theoretical derivation,when the basic wind pressure value of 1.3kN/m2,single girder and concentrated load center or on both sides of a third place,structure under the effect of partial load combinations have damaged;The maximum impact load of the mobile protective scaffold with a roof under safety protection is analyzed by numerical simulation.The results show that the maximum impact load is 135 kG based on the strength and stiffness respectively.The strength,stiffness,shear stress and rotation Angle of the model scaffold under different load conditions are analyzed by numerical simulation.(4)Comparison and verification of the effect analysis results of mobile protective scaffolding and design optimization.The theoretical calculation and numerical simulation results of mobile protective scaffolds were compared and analyzed.The theoretical calculation,model test and numerical simulation results of the model scaffold were compared and analyzed.Through comparative analysis,it can be seen that the curve trend of mobile protective scaffold and model scaffold analysis results are close on the whole,and the error is relatively small,which proves the rationality of different analysis methods.The similar model scaffold is reasonable and effective and can be used in other tests of mobile protective scaffold.Combined with the analysis results of the mobile protective scaffold,the design optimization scheme is proposed and verified by numerical simulation.