Mechanical Analysis Of Deck Pavement For Curved And Longitudinal Slope Steel Bridge

Due to the limitation of terrain or other structures,the urban interchanges,the bridges in mountain areas and some bridges connected with the main bridge usually adopt the curved bridge or large longitudinal slope bridge.To guarantee an adequate clearance,the flat steel box girder has been widely employed in the curved and longitudinal slope bridge.Differing from the flat and straight steel bridge,the vehicle loads exerted on these bridge are so more changeable,resulting in more complex bridge deck pavements.Shortly after the traffic opening,some bridge deck pavements suffer serious damages which cause great danger.Therefore,it is necessary to submit reasonable suggestions for pavement structure through the mechanical analysis of deck pavement for curved and longitudinal slope steel bridge.Firstly,the common diseases of curved and longitudinal slope steel bridge deck pavement are surveyed,and the causes of the diseases are analyzed.Four control indexes of the steel bridge deck pavement are put forward,including surface-tensile stress,the maximum vertical displacement,shear stress of bonding layer,and pavement layer maximum shear stress.Secondly,the finite element model of the steel bridge deck pavement structure is established.Then mechanical characteristics of different load positions and different calculating layers are analyzed,and the most unfavorable load positions of the control index of the steel bridge deck pavement are confirmed.Thirdly,based on the time-temperature equivalence of asphalt mixture,the stress distribution on the uphill vehicle is analyzed.Then the relationship between speed and paving material modulus is established.The influences of different speed,axle load and temperature on the maximum vertical displacement and the transverse shear strain of pavement surface are obtained.Based on the downhill vehicle braking effect,and the vehicle load analysis,it is found that the longitudinal slope and the horizontal force coefficients have effect on the shear stress of bonding layer.Multi-factor coupling effect of the longitudinal slope of the steel bridge deck pavement control index regression equations are proposed.Finally,based on the comparative analysis result of the steel bridge deck pavement at the curved and straight road,and the sensitivity analysis of pavement structure parameters,it is found that higher modulus in upper layer and lower modulus in bottom layer are helpful to reduce the maximum tensile stress on pavement surface and the maximum shear stress inside the pavement.Higher modulus in lower layer and upper modulus in bottom layer are beneficial to resist shear.In order to reduce the pavement structure stress,increasing the thickness of the upper layer is a good choice.Increasing the thickness of lower layer is conducive to the reduction of bond stress.The regression equations of the control index of curved steel deck pavement considering the influence of multi factors are proposed.