Concrete encased steel composite column with steel jacket using recycled concrete is proposed by the authors, and is being conducted continuous studies to make it practical. This paper discusses how to evaluate the axial strength of full scale columns. It is revealed based on the test results that the AIJ design formulas for SRC structures can be applied for evaluating the axial strengths of these columns. Furthermore, improved design formula to estimate the axial strength is proposed for these columns considering scale effect of concrete and local buckling of steel jacket.
