Abstract
We study the expansive concrete filled steel tube with a flat bar in center using for a brace member of the energy dissipative braced frame. From the discussion of the compression test results of the expansive concrete with a water-(cement+admixture) ratio 20 and 30% in the tube, we proposed the estimation formulae of the chemical prestress of the concrete at yield of the steel tube and we showed the idealization of the compression characteristics of the concrete and the steel tube
