Fatigue Performance Analysis And Model Test Research Of Composite Box Girder With Corrugated Web And Steel Bottom

In recent years,the composite box girder with corrugated web and steel bottom plate has received extensive attention as a new type of structure.It uses high-strength flat steel plates to replace the traditional concrete floor,and has carried out independent innovation and improvement in structural form.The corrugated web steel bottom plate composite box girder has a simple structure.The selection of the method of integral welding steel box girder reduces the total number of shear connectors,improves the integrity of the box girder,the force is more reasonable,facilitates engineering construction,and reduces the weight of the bridge.The span is larger,the steel base plate and the corrugated steel web can be prefabricated and assembled in the factory to further accelerate the construction progress.Have broader development prospects and market prospects.In order to better scientifically study the fatigue characteristics of this new type of composite structure,this paper conducted a research on the corrugated web steel bottom plate composite box girder under the new project "Research and Industrialization of the Complete Technology for the Construction of New Type of Highway Steel-Concrete Composite Bridges".On the basis of the understanding and summary of the scientific research on fatigue characteristics in the past,with reference to domestic and foreign standards,analysis and scientific research were carried out by means of scale model test and finite element simulation.The research on the fatigue performance of the structure in this paper has the following results:(1)After loading through fatigue dynamic load n times,perform static loading,scientific research has been carried out on the stress,deflection value and change law of the top and bottom plates and webs,and the changes in the integrity and stiffness of the model beams have been analyzed.According to the law of change,the stiffness of each part is slowly reduced under the action of static load,but it will not affect the structure.(2)Under the action of fatigue load,the stress,deflection value and change law of the top and bottom plates are analyzed,and the integrity and stiffness changes of the model beam under the load are analyzed,as well as the fatigue resistance of the model beam.Under the load of the circulatory system,the stress of the top plate and the bottom plate changes linearly,and the deflection value does not produce a sudden change,but linearly increases,indicating that there is fluctuation,but it is not enough to affect the structure.The test results show that the model beam has high rigidity,good structural integrity,and good fatigue resistance of the structure.(3)After 2 million cycles of cyclic loading,the changes in the stress and deflection values of the top and bottom plates are analyzed.According to the change law of the data,it can be concluded that the model beam is always in the elastic stage and has good fatigue resistance.(4)According to the finite element analysis,the normal stress and deflection values of the top and bottom plates under load are obtained,and the data information obtained by fatigue is used for data analysis and testing to verify the accuracy of the fatigue test.The data information obtained through finite element analysis is similar to the test data information,with little difference,and the overall change trend is the same,which well proves the accuracy and stability of the fatigue test data information.The deflection value measured in the test is basically the same as the deflection value simulated by the finite element analysis.In this paper,the fatigue performance of the corrugated web steel-concrete composite box girder is studied,and the research results have certain engineering reference significance for the design,construction and commissioning of this type of structure.