Experimental Behavior Of Concrete-filled Stainless Steel Tubes With Initial Concrete Imperfection Under Eccentric Tension

Concrete-filled stainless steel tube(CFSST)structure have outstanding mechanical properties of normal concrete filled steel tubular and various advantages of stainless steel,therefore,in coastal engineering,cross-sea bridge,marine platform,as well as to the beautiful and important buildings with high durability requirements,that new type of CFSST has great application prospect.Due to various factors in the structure of the actual project,Concrete-filled steel tube(CFST)components are often flawed,the existence of these defects affect the combination of the concrete-filled steel tube,thus affecting its mechanical performances.Hence,it is of great importance to have further researches in the mechanical properties of CFSST with initial concrete imperfection.In this paper,based on the experimental study and theoretical analysis,the eccentric tension behaviour of CFSST specimens with initial imperfection was carried out deeply.The main works can be summarized as follows:(1)By consulting domestic and foreign relevant papers review on stainless steel,concrete-filled stainless steel tube and concrete-filled steel tube with initial concrete imperfection in the experimental and theoretical research situation,and points out the research significance and the research content.(2)Including 24 CFSST specimens with initial imperfection specimens and 8 counterparts,32 CFSST were tested under eccentric tension in all.The experimental parameters include gap ration,load eccentricity.Gap ration,load eccentricity were included as the experimental parameters which impact on strength and stiffness were investigated.(3)The whole process of load-deform action relationships of CFSST columns under eccentric tension were analyzed by establishing the nonlinear finite element model.At the same time,the finite element model of reliability and accuracy were verified by using of the existing test results.(4)Basing on the finite element model,study of the influence regular of work mechanism that the effect initial concrete imperfection to CFSST under eccentric tension loading in-depth.Analysising the CFSST columns with initial concrete imperfection component failure mode and the load-deformation curve of the whole process.Analysising Distribution of CFSST and core concrete section stress and the contact stress between the stainless steel tube and core concrete.(5)Based on finite element model,effects of gap ratio,eccentricity,concrete strength,steel yielding strength and steel ratio on the N-? curve of CFSST members with initial imperfection were studied.