Influence Of Wheel Lateral Distribution On The Fatigue Damage Of Orthotropic Steel Bridge Deck

Orthotropic steel bridge decks are widely used in the construction of large-span bridges in the world due to their high strength,light weight,large bearing capacity and easy construction.However,under the repeated wheel loads,the fatigue failure of steel bridge decks occurs frequently.So,it is very important to carry out the reasonable anti-fatigue design.The focus of the anti-fatigue design is to accurately calculate the fatigue load spectrum of the structure.At present,the single-trace loading method is often used to calculate the stress spectrum for the steel bridge deck structural details,and the influence of the lateral distribution of the wheels is not considered.Thus,the calculated result is different from the actual stress spectrum.In this paper,the details of two kinds of fatigue and fragile structures in the steel bridge deck of Pingsheng Bridge are taken as an engineering example.The effects of three kinds of wheel lateral distribution probability models on the fatigue damage of the vulnerable structure details are investigated.The main work is as follows:(1)The development history of orthotropic steel bridge deck all over the world is reviewed.In addition,the reasons and the current research situations for the fatigue failure of the steel bridge decks are briefly summarized.The research results of the horizontal distribution of wheels at home and abroad are sorted out.On this basis,a probability model of the horizontal distribution is proposed in this paper.The development history for the fatigue analysis theories of steel bridge decks is introduced,and the corresponding approaches are summarized.Three fatigue damage accumulation theories are introduced,and their advantages and disadvantages are compared and discussed.(2)Taking Pingsheng Bridge as an engineering example,the full-bridge finite element model is established to find the most unfavorable section under the dead load.And,the segment finite element model is established.The finite element mesh is fined at the position of the local wheel loads.The fatigue failure positions in the bridge segment are determined.Besides,,and the fatigue vehicle load model is determined according to the fatigue damage equivalent principle.(3)The fatigue vehicles are loaded at different lateral positions.The stress values for the different measuring points are obtained.According to the linear cumulative damage theory and the BS5400 specification,the daily damage degree of each measuring point is calculated.Considering the lateral distribution of the wheels,the influence of three typical wheel lateral distribution probability models on the structural fatigue damage degree is addressed.