Research On Mechanical Response Of Long-span Steel Box Bridge Deck Pavement

As pavement material,asphalt mixture has advantages such as protecting bridge deck, prolonging service life,promoting crane comfortability,reducing vibration and noise, though different mechanical characteristics of different bridge types and variance between pavement materials and steel decks cause pavement cracking,disengagement between pavement and deck,rut and other early damage. This paper makes researches on the pavement system of long-span steel box bridges,provides new analysis method and thinking on optimization and damage analysis of pavement system. Main research works in this thesis are as followed:(1) Nonlinear analysis of ZhuJiang HuangPu steel suspension bridge was proceeded, a local box beam with the biggest bending moment was extracted and a finite element model of it was built, displacement constraints conditions on the interface of beam model and shell-solid model were introduced, finite element analysis was proceeded, results were compared with finite element analysis results of local pavement systems.(2) A 12-nodes solid shell element was constituted and a method of analyzing nonlinear contact problem was adopted. Spatial analysis model was constituted by 8 nodes solid shell element, Goodman contact element and 12 nodes solid shell element. The user program was implemented through UPFs secondary exploitation technique of ANSYS software. Spatial pavement system analysis model was constituted. Detail analysis was carried out on sensitivity of pavement system mechanical indexes according to contact state change and least-squares method was used to express mathematical relation between tangential stiffness coefficient and mechanical indexes. According to different material parameters and structure parameters, pavement system was analyzed and incomplete contact conditions were considered. Key factors that can reflect mechanical properties indexes were defined, reasonable range of pavement material and steel bridge deck were determined.(3) A changing method of relaxation and creep function of asphalt mixture was proposed under corresponding fundamental relationship of relaxation curve and creep curve. Combined with characters of steel deck pavement system, detailed research on the visco-elastic response of steel bridge pavement which endured the automobile load was implemented. Quasi-elastic method was used to analyse basic law of pavement system mechanical response according to different temperatures and different contact conditions between steel deck and pavement. Variation pattern of mechanical response was analysed under the conditions of loading and unloading.(4) Leading coupling effect of creep damage and fatigue damage into asphalt mixture creep model, expression of creep-fatigue damage factor was given. Corresponding dissipated energy relations between steel deck composite beam fatigue test and creep test in constant stress was established and creep feature forecast method of asphalt mixture was proposed by composite beam fatigue test. Stress-fatigue life relation of pavement material equation was proposed by energy methods.