Investigation of concrete-filled stainless steel tubular X-joints

Abstract

Experimental and numerical investigation of concrete-filled stainless steel tubular X-joints were conducted. The specimens were fabricated from square and rectangular hollow sections (SHS and RHS) with nominal concrete cylinder strength of 30 MPa filled in the chord members. The tests were performed by using steel bearing plates to transmit transverse compression force to the concrete-filled chord members. A numerical study was performed using finite element analysis. The geometric and material nonlinearities of stainless steel tubes as well as the concrete infill were carefully incorporated in the finite element model. The numerical results showed good agreement with the experimental results. Therefore, the parametric study was performed using the verified finite element model to investigate the strength and behaviour of concrete-filled stainless steel tubular X-joints. Chord face failure and chord side wall failure as well as crushing of concrete were the main failure modes observed in the parametric study. The joint strengths obtained from the parametric study and tests were compared with the design strengths calculated using the CIDECT design rules for concrete-filled carbon steel tubular joints. It is shown that the design strengths calculated using the existing design equations are quite conservative.