Performance of concrete-filled bimetallic tube short columns under eccentric compression: Experimental investigation

Abstract

Concrete-filled bimetallic tubes (CFBTs) combine the mechanical advantages of concrete-filled steel tubes (CFSTs) and the functional features of bimetallic tubes. This paper presents the test results of fifteen circular short column specimens under eccentric compression. The bimetallic tube adopted in the current research was manufactured by combining an inner carbon steel tube and a cladding stainless steel layer, which can improve the corrosion resistance of the conventional carbon steel tube with economic efficiency. A total of fifteen specimens, including seven hollow bimetallic tubes and eight CFBT short columns, were fabricated and tested by considering the nominal load eccentricity (en/D = 0, 0.26, 0.53, or 0.79) as the main testing parameter. The test results indicated that all the CFBT short columns behaved in an improved ductile manner compared to the hollow bimetallic tubes, and the corresponding load-carrying capacity was significantly enhanced. The development of strain in the two tube layers demonstrated the inner and outer steel tube layers worked well together. The influences of load eccentricity on the mechanical behavior of CFBT short columns were discussed. Finally, an improved model was suggested for calculating the N/Nu-M/Mu interaction relationships of CFBT short columns subjected to eccentric compression.