Under Slab Hollow Condition Vehicle Load On Double Layer CRCP Steel Stress Influence Simulation Analysis

Based on the science and technology plan project of Wuhan Urban Construction Committee--The Design and Technology Research of Bilayer Continuous Reinforced Concrete Pavement of City Road Under the Condition of Heavy Load(project number: 201502)--and Bilayer CRCP project at “Wuhan Route 21”on the one hand,and with the help of finite element modeling analysis software ANSYS as well as on the basis of void under slab on the other hand,this thesis aims at exploring the influence of road structure changing on the stress of Bilayer CRCP steel under heavy vehicle load and the most unfavorable voids through sensitivity analysis and multiple linear regression.First,the study starts from the location of void,via comparing and analyzing three different conditions under no void,the void in the slabs and the voids in the plate,finally finds that comparing with the condition without void,the void in the slab has a little influence on the stress of Bilayer CRCP steel,and the void in the plate is the most harmful position;with the increasing of void size,the stress growth rate of Bilayer CRCP steel decreases,which indicates that Bilayer CRCP has a very good effect on resisting the diseases from large-scale voids.Then,based on the most unfavorable position of voids(voids in plate),the stress of the upper and lower steel bars shows different objectives through analyzing the substrate modulus?thickness and the influence of subgrade modulus on the stress of Bilayer CRCP: upper steel bars are subjected to compression stress,which is mainly related to the modulus of subgrade and the void size,while substrate has a small effect;lower steel bars are subjected to tensile stress,which is mainly related to the substrate modulus and thickness,while the effect of subgrade modulus is small.In the analysis,it is also found that the location of the neutral layer of the Bilayer CRCP plate is obviously affected by the substrate,and the neutral layer is always in the lower part of the surface layer,which means the lower steel bars have smaller stress than the upper one.In the end,based on the results of finite element analysis,a simplified formula for the maximum stress of the upper and lower longitudinal reinforcement influenced by the Bilayer CRCP under the vehicle load toward the multiple linear regression analysis of the load stress of the upper and lower steel bars of Bilayer CRCP at “Route 21,and the formula includes five independent variables: the thickness of the base concrete,the modulus of the plain concrete,the void size,the subgrade modulus and the vehicle load.Through the sensitivity analysis of single factor,it is proposed that the relationship between the maximum stress of longitudinal reinforcement and the individual factors is determined.Finally,much more precision prediction formulas of the steel bar stress which has been satisfied with the hypothesis test is obtained through the analysis of the hypothesis of the variables.