Study on Axial Compressive Capacity of FRP-Confined Concrete-Filled Steel Tubes and Its Comparisons with Other Composite Structural Systems

Table 4

Comparisons of CCFST, CFFT, DSTC-H, and DSTC-F.

Type	Specimen	(mm)	(mm)	(MPa)	(MPa)	(MPa)	(kN)	(MPa)
CCFST	average	0.334	2.0	31.2	275	2878	1948.8	91.2
CFFT [20]	N-150C2L-2	0.234	—	34.6	—	3626	1104.5	60.9
DSTC-H [21]	DSTC-2	0.234	3.2	37.0	302	3626	955.0	99.9
DSTC-F [21]	DSTC-4	0.234	3.2	36.7	302	3626	1322.0	74.9

Note. = the 28-day compressive strength of concrete; = the total nominal thickness of CFRP; = the thickness of steel tube; CFRP tubes of CFFT, DSTC-H, and DSTC-F were made of two layers of CFRP (nominal thickness is 0.117 mm/ply), while CCFSTs were wrapped with two layers of CFRP sheets (nominal thickness is 0.167 mm/ply).