Study On The Interaction Of Steel Deck-pavement System Under Temperature Effect During Asphalt Concrete Paving

The high paving temperature of asphalt concrete pavement brings temperature field on steel box girder bridge,which is non-linear and time-space dependent.Steel box girder is deformed under the coupling of traffic-and thermal-induced loading.The deformation characteristics and the stress loading mechanism are very complex.The high paving temperature does not only affect the performance of composite paving layer of the bridge,but also potentially threaten the safety of the entire bridge structure.However,this problem has not attract enough attention so far.This study investigated the paving temperature field of steel bridge deck based on the response of bridge to temperature field.The impact of paving temperature on the steel box girder bridge and the interactions within the bridge pavement system were also explored.Firstly,according to Fourier law and heat balance principle,the heat differential equation of the three-dimensional(3D)transient temperature field was inferred,and the mathematical expression of paving temperature with respect to time and space was determined.The heat transfers in the boundary and inner structures of paving temperature field were also analyzed based on heat transfer principle.The boundary condition was discussed using the third-kind boundary condition of the heat conduction.The direct integral method of the transient thermal field and the solution for the elastic thermal stress were explored.Secondly,the thermal field of steel bridge deck was measured by in-situ temperature monitoring technology to analyze the time and spatial distributions of the local thermal field in the composite pavement system.The real-measured data was used to determine the relevant thermodynamics parameters.The element deletion method was adopted in finite element models to simulate the dynamic process of asphalt pavement paving,so a numerical simulation method used for paving temperature field of asphalt concrete was created.Thirdly,based on the transient heat transfer theory,the thermal-solid coupling numerical simulation model of the thermal field in a flat steel box girder during the double-layered asphalt pavement was established to analyze the 3D temperature distribution of the steel bridge deck.Trigonometric and exponential functions were used to fit the worst transverse and longitudinal temperature loading model of the steel bridge deck,and to quantify the 3D temperature change.Meanwhile,the influential factors were acquired based on the response analysis of paving thermal field.The paving temperature load equations of different influencing factors were presented.Fourthly,using the sequential coupling thermodynamics calculation method,results of the thermal field were input into the established three-stage thermodynamic model to calculate temperature effect,thermal-solid coupling steel bridge structure displacement and the time and spatial distribution law were investigated.Furthermore,the impact of temperature on bridge structure was analyzed.Then,the shear stress at the adhesive layer and the stress within the pavement layer under thermal loading were analyzed.The shear strength obtained from laboratory shear test was used to verify the shear strength of adhesive layer.Lastly,the transverse stress,longitudinal stress and vertical deformation of the steel girder were analyzed under the coupling of thermal loading and construction loading.Results showed that since the steel box girder cross section does not reach the worst temperature load,the mechanical response index of steel bridge deck is still lower than that at the worst temperature loading moment under the working load coupling.Moreover,the numerical simulations with various model parameters were conducted to study the influence of the orthotropic deck's parameters and layout on the thickness and mechanical index of pavement layers,and analyze the impact of pavement layer thickness and modulus on the mechanical response of orthotropic deck.In addition,the orthogonal test was carried out to explore the characteristics and interaction between steel bridge deck and pavement layers.In conclusion,based on transient heat transfer theory,this study investigated the thermal field and its effect on steel bridge deck during paving process through the in-situ monitoring and numerical simulation.The steel bridge deck-pavement interaction was explored as well.Research results well revealed the time and spatial distributions of the thermal field,the effect on steel bridge deck paving,and the characteristics of the interaction of the bridge deck layered composite system.The findings in this paper can guide the design,construction and maintenance of the steel bridge deck pavement,mitigate the influence of high-temperature paving on bridge structure,and inhibit the occurrence of pavement layers' premature distresses.