Numerical Simulation Analysis On Mechanical Characteristics Of Deck Pavement Of Small Radius Curved Slope Bridge

As an important part of the bridge,the deck pavement plays a decisive role in distributing the load and ensuring the safety of traffic.Due to the low stiffness and high deformation of the steel deck,the pavement is subject to complex stresses and is prone to rutting,rolling deformation and other damages.In order to meet the traffic needs under the constraints of terrain,land and other restrictions,engineering often build longitudinal slope,small radius curve bridge,but compared to straight bridges,curve bridge pavement layer is more unfavorable forces,more likely to suffer damage,so the pavement layer is required to have a higher high temperature stability and interface safety.Therefore,in this paper,in order to study the mechanical characteristics of the deck pavement of small-radius curved-slope bridge,the temperature field and the moving load subroutine under two-wheel uniaxial load are written,and the model of steel box girder bridge with asphalt mixture pavement layer based on viscoelastic characterization is established,and the mechanical responses generated by the deck pavement of small-radius curved-slope bridge under four conditions of temperature field,temperature stress field,dynamic load stress field and temperature-load coupling stress field are studied respectively,and the effects of temperature field,longitudinal slope,radius of curvature,pavement modulus,pavement combination,and vehicle speed on the force characteristics and fatigue life of the pavement are analyzed,and the main research results are as follows.(1)The moving load subroutine with curved trajectory was written in fortran language to realize the loading of dynamic load of small radius curved slope bridge,and the temperature field subroutine was written to realize the study of temperature field of curved bridge under simulated harsh environment.(2)According to the actual working conditions of the rainbow interchange pavement technology research project in Kangding transit section of G318 national highway,the finite element software ABAQUS was used to model the full bridge deck pavement of small radius curved slope bridge,and analyze the stress characteristics of the small radius curved slope bridge deck pavement,the research shows that: the road surface undergoes daily changes in the high temperature season than in the low temperature season;as the magnitude of alternating tensile and compressive stresses affects the fatigue life of the pavement layer The fatigue life of the pavement is affected by the magnitude of alternating tensile and compressive stresses,and the maximum difference in tensile and compressive stresses in one day is much greater in the summer high temperature season than in the winter low temperature season,so it is more likely to produce temperature shrinkage cracks in the winter low temperature season;the temperature-load coupling will reduce the most unfavorable stresses on the pavement,and the stresses on the curved slope bridge pavement will be inhibited and reduced,which is more favorable to the stresses on the curved slope bridge pavement.(3)By changing the parameters of longitudinal slope,radius of curvature,grade combination,pavement modulus and vehicle speed of curved bridge,the effect of each parameter on the mechanical response of the surface and subgrade of the bridge deck was analyzed.In winter low-temperature season,the pavement base layer material AC-20 is more conducive to pavement cracking and shear resistance;increase the pavement modulus and use the upper layer modulus low,the lower layer modulus high pavement combination is more conducive to the pavement force.(4)By changing the parameters of longitudinal slope,radius of curvature,grade combination,pavement modulus and vehicle speed of the curved bridge,the effect of each parameter on the fatigue life of the surface layer and the bottom layer of the bridge deck was analyzed,and the study showed that the fatigue life of the pavement increased with the increase of longitudinal slope,radius of curvature,pavement modulus and the decrease of vehicle speed.