Experimental Study On Lateral Bending Performance Of New Steel-UHPC Composite Bridge Deck

The composite bridge deck structure formed by ultra-high performance concrete(UHPC)and steel bridge deck has the advantages of high bearing capacity and good crack resistance.Under vehicle load,the negative bending moment zone will be formed near the longitudinal diaphragm of steel-UHPC composite bridge deck,resulting in large transverse tensile stress and controlling the design.In order to explore the related performance of the new structure form,this paper studies the lateral bending resistance of the new steel-UHPC composite bridge deck based on the Fulong Xijiang Bridge in Foshan.This chapter and related research work are as follows:Chapter 1:The presentation and material properties of steel-concrete composite structure and ultra-high performance concrete(UHPC)are briefly introduced,and their respective structures and mechanical characteristics are briefly expounded.On this basis,through some problems existing in the current steel-concrete composite structure,the concept of steel-UHPC composite structure is introduced.At the same time,the research results of steel plate-concrete composite structure at home and abroad are collected to lay the foundation for the follow-up study of this paper.Chapter 2:Two new steel-UHPC composite bridge decks(the reinforcement ratio of the tensile upper reinforcement is 0.89%)were subjected to cross-bridge static load bending test.The strain,midspan deflection,relative slip,crack width and failure mode of each measuring point under different bending static loads were investigated.The cracking stress(cracking strength)and ultimate stress(ultimate strength)of the new steel-UHPC composite bridge deck under transverse bending were calculated by the section conversion method of steel-concrete composite beams.According to the plastic calculation theory of conventional composite beam,based on the ultimate bearing capacity and the neutral axis obtained from the test,assuming that the stress diagrams of each part are rectangular,the reduction coefficients of UHPC tensile strength and steel plate compressive strength under negative bending bearing capacity of steel-UHPC composite bridge deck are obtained.Chapter 3:Considering the nonlinearity of materials,the ABAQUS finite element model for nonlinear simulation analysis of the whole process of static loading of composite bridge deck is established by using the plastic damage model of concrete and setting the steel-UHPC interface contact properties and boundary conditions.The load-mid-span deflection curve,load-strain curve of each measuring point and crack development law obtained by the finite element method were compared with the corresponding test results.The fourth chapter:Based on the finite element model calibrated in the third chapter,the parametric analysis is carried out to explore the influence of UHPC tensile strength,top longitudinal reinforcement ratio and steel plate strength on the static performance of negative bending moment of bridge deck.According to the parameters of the above finite element model,the adaptability range of UHPC tensile strength and steel plate compressive strength reduction coefficient in the bearing capacity of negative bending moment of steel-UHPC composite bridge deck obtained in the second chapter is analyzed,and the structural design of steel plate-UHPC composite bridge deck is proposed.