Research On Mechanical Properties Of Long Span Suspension Bridge Deck Surfacing Subjected To Coupling Of Temperature And Load

Surveying the operation situation of the deck pavement in Yunnan Province,most of the pavement appear certain diseases,such as cracking or rutting,after opening to traffic.Environmental temperature and load condition are two key factors dominating the performance of steel bridge deck pavement.Most of the existing researches in this area concentrated on the analysis of mechanical characteristics of pavement at several constant temperatures,without sufficient consideration of the periodic temperature conditions.In this thesis,based on the temperature field model of bridge deck surfacing,five typical concrete bridge deck pavement structures are selected,the mechanical response and permanent deformation of long span suspension bridge deck surfacing subjected to coupling of temperature and load conditions are mainly analyzed.Firstly,the diseases of concrete bridge deck pavement in Yunnan Province are classified and analyzed,based on the special climatic conditions in Yunnan Province,the influencing factors and causes of several typical concrete bridge deck pavement diseases are analyzed.Temperature is one of the most important causes.The design principles of long span suspension bridge deck surfacing in Yunnan Province are proposed.Secondly,when analyzing mechanical properties of the pavement structure in the condition of periodic temperatures,the most unfavorable condition is selected.The finite element model is used to calculate the temperature field of pavement,the temperature field is also periodic.Thermal stress of the pavement structure in the condition of periodic temperatures is analyzed,which is considered as the initial stress field of the pavement.The numerical variation of thermal stress in the condition of continuous temperature drop is obvious,the maximum of surface stress change is 1.7MPa.Then,the mechanical responses of the pavement under traffic loads in the most unfavorable condition are studied.Finally,considering the daily variation regularity of the traffic the creep parameters of the mixture at different temperatures,the permanent deformation of the pavement in the condition of periodic changing temperature is analyzed with finite element method.The influences caused by different contact pressure are also studied.The anti-rutting performance of structure EA+SMA is the best.The rutting depth is 0.17mm after the standard axle load of 500000 times.The permanent deformation increases 15%and 25%with the contact pressure of 0.9MPa and 1.1MPa.