Concrete-filled bimetallic tubes under axial compression: Experimental investigation

This paper presents the experimental results of axial compression tests on concrete-filled bimetallic tubes (CFBT). The cross section of the bimetallic tube is composed of an outer layer made of stainless steel and an inner layer made of carbon steel. A total of 12 specimens with a circular cross section were tested under axial compression. The test parameters included the thickness of the stainless steel tube layer (tss=0-1.36 mm) and the compressive strength of the infilled concrete (fcu=21.1-42.8 MPa). Test results showed that, the two layers of the bimetallic tube worked well together, and the CFBT specimens exhibited ductile characteristics. The influence of the parameters on the failure mode, load versus deformation relationship, axial compressive strength, and strain development of the tested specimens were investigated. Finally, the feasibility of three existing design codes for predicting the axial compressive strength of CFBT under axial compression was evaluated.