Investigation of flexural performance of double skin concrete filled steel tube beams

Concrete Double Skin Steel Tube (CFDSST) beams are consist of two skins of steel filled with concrete between them. CFDSST member is lighter than Concrete Filled Steel Tube (CFST) members, which has a solid cross-section. Therefore, by lessening seismic force against the structures during an earthquake, the CFDST members can be effectively applied to the seismic resistance structures such as the high-rise buildings, bridge piers, etc. This thesis deals with are an experimental investigation of the effect of cross-section and the position of the inner tube on the flexural performance of CFDST beams. A total 13 CFDST beams specimens filled with self-compacted concrete was tested. The parameters examined in the test: (a) inner tube cross-section (square and rectangular) (b) the position of inner tube (center and bottom). Comparisons are presented between the examined specimens according to the flexural strength, failure modes, ductility and flexural stiffness.