抄録
Concrete filled double steel tubular columns (CFDT in abbreviation) consist of two centric steel tubes and filled concrete between them. By the arrangement of inner tube, the own weight can be reduced in comparison with ordinary concrete filled steel tubular members. Centric loading tests on twelve specimens of CFDT were carried out. Observed failure mode was local buckling of both tubes associated with shearing failure of concrete. Axial strength of CFDT were agreement with or larger than accumulative equation consisting of two steel tubes and filled concrete. However, the larger inner-to-outer diameter's ratios, yield the smaller axial lnadinu canacities. Moreover. empirical equation of axial strength of CFDT was proposed.
