Experimental research on circular concrete filled stainless steel tubular truss

The flexural behaviour of circular concrete filled stainless steel tubular trusses is presented in this paper. A total of four specimens were tested, including three circular concrete filled stainless steel tubular truss and one hollow circular stainless steel tubular truss. All specimens were tested under static load. The main parameter explored in the test included the location of concrete-filled. (Case 1: Concrete-filled top chord. Case 2: Concrete-filled bottom chord. Case 3: Concrete-filled top and bottom chord. Case 4: Hollow circular stainless steel tubular truss.) This paper presents the failure modes, overall deflections, load-strain curves, load versus displacement curves and load carrying capacity of all the tested specimens. It was found that the typical failure mode includes: the surface plasticity of the top chord, the weld fracture and crack around tubular joints at the bottom chord, and the bent of the top and bottom chords. The flexural rigidity, load carrying capacity and ductility of different types of circular concrete filled stainless steel tubular trusses are different due to the remarkable changes of the location of concrete-filled. It is demonstrated from the comparison that the truss of concrete filled in both top and bottom chord (CC100×2.0-BC76×2.0-C30A) has the best flexural rigidity and the greatest load carrying capacity per unit truss weight. Whereas, the truss of concrete filled in top chord (CC100×2.0-BC76×2.0-C30T) has the best ductility.