Design of concrete filled tubular CHS T-joints under in-plane bending

Experimental investigation was conducted to study the ultimate strengths of concrete-filled tubular CHS (Circular Hollow Section) T-joints under in-plane bending loading. The main chord was loaded in compression while the brace was under in-plane bending loading. Three concrete filled steel T-joints were tested. The failure modes and ultimate strengths of test specimens were obtained. Test results indicate that the filled concrete has significant effect on the ultimate strength of T-joints. Design equations for the concrete-filled T-joints under in-plane bending were proposed. Width of weld, contribution of concrete in compression and variation of thickness at the chord punch shear face were considered in the proposed equations. It is shown that predictions obtained from the proposed equations are generally accurate compared with test results. In addition, simplified equation was also proposed.