Behavior of thin-walled dodecagonal section double skin concrete-filled steel tubular beam-columns

• Beam-column tests of dodecagonal section double skin concrete-filled steel tubes were presented in this study.
• The load─displacement curves, load─strain curves, failure modes and ultimate loading capacity of test specimens were obtained.
• Parametric study was carried out using the verified finite element model.
• The suitability of proposed design equations was evaluated.

The behavior of thin-walled dodecagonal section double skin concrete-filled steel tubular beam-columns was investigated in this paper. A series of tests were carried out on specimens having the length of 2000 mm. Both outer and inner tubes of test specimens were cold-formed steel dodecagonal hollow sections (DHS). The diameters of outer and inner steel tubes of test specimens were 400 mm and 240 mm, respectively. Each test specimen was tested to failure, and the behavior under loading was recorded. Finite element model was developed using ABAQUS and verified against the test results. Parametric study was conducted using the verified finite element model. The suitability of current design methods was evaluated.