Experimental Study on Axial Compression Performance of 7A04 High Strength Aluminum Alloy Circular Tube Concrete Short Column

Table 6

Ductility index and coefficient of strength improvement.

Specimen label	Confinement coefficient	Ductility index DI	Coefficient of strength improvement
ACST3	1.31	3.23	1.63
ACST5	2.28	4.58	1.79
AHCST3	0.735	2.59	1.09
AHCST5	1.27	4.03	1.49

is the yield strength of aluminum alloy, is the confinement coefficient, is the yield strength of aluminum tube, is the axial compressive strength of concrete, is the sectional area of aluminum tube, and is the axial compressive strength of concrete, sectional area of concrete.