The In-plane Failure Critreion Of Steel-concrete-steel Composite Structure

Steel-concrete-steel composite(SCS)structure is a kind of sandwich structure consisting of two layers of steel faceplates and infilled core concrete.The main system to suffer the force is the outer steel faceplates and the inner filled concrete,and also the channel steel connectors or steel bars are used to strengthen out-of-plane shear performance.Through the mutual restraint between the steel plate and the concrete,SCS structure features good ductility,and the ability to prevent leakage,impact and explosion.To investigate the in-plane performance of SCS composite structures,8 composite specimens were tested.The load types were uniaxial tension,compression and combined tension and compression.During the test,biaxial principle strains of the specimens,the inner and outer strains of the steel plates,the strains of steel bars and flanges were measured,the maximum carrying capacity was obtained in the biaxial proportional loading.The experimental results show that the SCS composite member has high carrying capacity and good ductility suffered the in-plane forces.As SCS walls are in-plane stress state in most practice,this paper focus on the in-plane behavior of SCS composite elements.Firstly,the failure criterion is established which is based on the limit analysis with taking stress redistribution of steel plate and concrete into account,and has good consistency with the test results.Secondly,in order to study the loading process of the element,based on the elasto-plastic analysis,the post-yield stiffness matrix of the steel plate satisfying the Prandtl-Reuss ideal elastic-plastic material model is deduced.A numerical model for calculating SCS element suffered in-plane force is proposed,which has a good consistency in the simulation of the loading process,and the acquired failure criterion deviates the experimental result slightly.Through the analysis of the deviation,the deviation of the limit analysis model is more uniform in the biaxial loading(combined tension and compression),while the numerical analysis model mainly appears in the large compression to tension.In addition,considering the yield strength of construction steel as the design stress in engineering,the concept of yielding criterion of SCS composite element is put forward which regards the steel plate reaching the initial yielding state as the yielding of the element.The yielding criteria of the element based on the steel plate satisfying Tresca criterion and von Mise criterion are obtained,based on mechanical analysis and numerical analysis respectively.And the method of obtaining the yield load in the test is given.The yield load obtained by this method is in good agreement with the two yield criteria proposed in this paper.The deviation of the two yield criterion mainly occurs in the large compression to tension(excluding the uniaxial compression).Furthermore,the FEM models(by ABAQUS)are used to research the in-plane performance of SCS composite element,and further to verify the accuracy and applicability of the established failure criterion and yield criterion models.