Table 3.
The parameters of specimens.
| Specimen | Outer square steel tube B0 × t0 (mm) | Inner square steel tube D0 × t0 (mm) | Hollow ratio χ | Concrete strength grade | Column height H (mm) | Number of CFRP layers |
|---|---|---|---|---|---|---|
| S120 × 3_20 × 3_0 | 120 × 3 | 20 × 3 | 0.17 | C30 | 500 | – |
| S120 × 3_40 × 3_0 | 120 × 3 | 40 × 3 | 0.33 | C30 | 500 | – |
| S120 × 3_60 × 3_0 | 120 × 3 | 60 × 3 | 0.50 | C30 | 500 | – |
| S120 × 3_20 × 3_1a | 120 × 3 | 20 × 3 | 0.17 | C30 | 500 | 1 |
| S120 × 3_20 × 3_1b | 120 × 3 | 20 × 3 | 0.17 | C30 | 500 | 1 |
| S120 × 3_20 × 3_3a | 120 × 3 | 20 × 3 | 0.17 | C30 | 500 | 3 |
| S120 × 3_20 × 3_3b | 120 × 3 | 20 × 3 | 0.17 | C30 | 500 | 3 |
| S120 × 3_40 × 3_1a | 120 × 3 | 40 × 3 | 0.33 | C30 | 500 | 1 |
| S120 × 3_40 × 3_1b | 120 × 3 | 40 × 3 | 0.33 | C30 | 500 | 1 |
| S120 × 3_40 × 3_3a | 120 × 3 | 40 × 3 | 0.33 | C30 | 500 | 3 |
| S120 × 3_40 × 3_3b | 120 × 3 | 40 × 3 | 0.33 | C30 | 500 | 3 |
| S120 × 3_60 × 3_1a | 120 × 3 | 60 × 3 | 0.50 | C30 | 500 | 1 |
| S120 × 3_60 × 3_1b | 120 × 3 | 60 × 3 | 0.50 | C30 | 500 | 1 |
| S120 × 3_60 × 3_3a | 120 × 3 | 60 × 3 | 0.50 | C30 | 500 | 3 |
| S120 × 3_60 × 3_3b | 120 × 3 | 60 × 3 | 0.50 | C30 | 500 | 3 |
B0 is the side length of the outer rectangular steel tube, D0 is the side length of the inner rectangular steel tube, t0 is the thickness of the pipe.
S120 × 3_20 × 3_1b: “S”—square steel tube;“120 × 3_20 × 3”—parameter of outer and inner steel tube;“1”—number of CFRP layers; “b”—distinguishing the same parameters.