Theoretical And Experimental Study On The Behavior Of Curved Concrete-filled Stainless Steel Tubular Members

This paper describes the mechanical behavior of curved concrete-filled stainless steel tubular(CFSST)members subjected to axial compression or eccentric compressive and bending.Based on regression analysis,simplified calculation formulae of bearing capacities for curved CFSST members were put forward.The main achievements can be summarized as follows:(1)Experimental investigation on sixteen single curved CFSST members under axial compression was carried out,in which 15 circular specimens and 1 stainless steel tubular were included.Initial deflection and slenderness ratio were selected as the main parameters for this study.With the increase of initial deflection and slenderness ratio bearing capacity decreases.(2)Load versus deformation relationship curves of single curved CFSST members were analyzed using finite element method.The changes of the stress distributions in the stainless steel tube and core concrete,as well as the interaction between the steel tube and core concrete,throughout the loading process were investigated.Based on an extensive parametric analysis,a simplified calculation method of bearing capacity for single curved CFSST members were proposed.The failure model of curved CFSST is similar to the CFSST.But the flexural capacity of the curved CFSST is higher than the CFSST.(3)Experimental investigation on four curved CFSST members and one stainless steel subjected to bending was carried out.The investigating parameters included initial deflection.The performance and failure modes of the specimens were studied,which were also compared with those of straight member and stainless steel tubular.(4)Behavior of curved CFSST members subjected to bending was analysed using finite element method.The analytical results agree well with those of tests.The effects of initial deflection were analysed.Based on the parametric analysis,simplified calculation methods for bending stiffness,load-bearing capacity for built-up member,load-bearing capacity for lacing element or batten were proposed.Some construction suggestions for curved built-up CFSST members were also proposed,which may be referred for practical engineering design.