Research On The Stress And Fatigue Damage Of Steel Box Girder Bridge Deck U-rib Under The Wheel Track Lateral Distribution

Orthotropic steel bridge decks are widely used in long-span bridge structures because of their many advantages.However,this structure is complex and stress concentrations are prone to occur at the welds.The fatigue problem is prominent under the repeated effects of various loads.Anti-fatigue analysis of steel bridge decks is very important.In this paper,the joint where U-ribs and diaphragms are most prone to fatigue cracks in steel bridge decks is taken as the research object.The traditional single-track loading method is abandoned,and the stress on the connection of the wheel tracks is taken into consideration.Calculate and analyze with fatigue damage,and discuss the impact of three kinds of wheel track distribution probability models at home and abroad on the fatigue damage of joints.The single parameter method was used to optimize the stress and fatigue performance of the connection between the U-rib of the steel bridge deck and the diaphragm,and the reasonable values of the corresponding parameters were recommended.The main work is as follows:(1)The development process of orthotropic steel bridge deck is summarized,the background,types and research status at home and abroad are summarized,the basic concept and analysis method of fatigue are summarized,and some problems existing in the research process of orthotropic steel bridge deck are put forward.(2)Analyze and compare the existing probabilistic model of wheel track lateral distribution at home and abroad,consider the influence of factors such as lane width,vehicle type,etc.,establish a new model of probabilistic wheel track lateral distribution,and demonstrate its accuracy.(3)Establish the finite element model of several sections around the most unfavorable load position of the bridge,load the standard fatigue load at different transverse positions,obtain the stress distribution at the joint of U-rib and diaphragm,and calculate the fatigue damage degree according to the fatigue damage theory and corresponding codes.Considering the probability of lateral distribution of wheel tracks,explores the influence of three new and old probability models on the fatigue damage degree of the research site,and makes a comparative analysis.(4)Based on the background of this paper,the single parameter method is used to adjust the structural parameters of the orthotropic steel bridge deck,and load is applied to study the stress conditions of the orthotropic steel bridge deck with different structural parameters under load,analyze its stress characteristics,and put forward suggestions for optimizing the stress characteristics and anti fatigue characteristics of the orthotropic steel bridge deck.