Behaviour and design of short high-strength steel welded box and concrete-filled tube (CFT) sections

This paper presents an experimental investigation on the ultimate strength of short welded box (HS) and CFT sections (CB) fabricated from high strength steel (HSS) and filled with high strength concrete (HSC). This paper additionally presents experimental data on steel only loaded sections (CS) and concrete only loaded sections (CC). Forty-five test specimens having width to thickness ratios (b/t) ranging from 15 to 40 and length to width ratios (L/b) ranging from 3.5 to 5 were tested. Finite element modelling (FEM) of the test specimens (HS, CS and CB) was verified with the experimental results. The FEM was used to investigate the effect of induced residual stresses on the ultimate strengths for lightly and heavily welded box sections. Furthermore, FEM of the test specimens (CB) was used to investigate the adequacy of design specifications pertaining to square CFT sections fabricated from HSS and HSC. Experimental and FEM results suggest that the current design specifications are adequate to predict the ultimate strengths of square CFT sections fabricated from HSS (690 MPa) and HSC (90-130 MPa).