Table 2.
Experimental results and failure characteristics of all specimens after complete collapse.
| Group# | Specimen | fcu (MP)a | Cracking load (kN) |
Pu (kN) | Deflection (mm) | Toughness (N mm) | Ultimate strain at failure, micro-strain |
Dominant mode of failure | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Beam | Column | Joint | MS Beam | MS Column | Stirrup | Column2 | FRP 1 | FRP 2 | |||||||
| Control | J0 | 25.4 | 10 | 25 | 45 | 79.8 | 40.2 | 2655 | 2350 | 1479 | 1310 | – | – | – | Flexural failure of the beam |
| Group #1 | JI0 | 24.8 | 10 | 25 | 40 | 67 | 29.6 | 1733 | 1600 | 1428 | – | – | – | – | Shear failure at the joint |
| JI1 | 25.1 | 10 | – | – | 103.8 | 19.3 | 1276 | 2780 | 1462 | – | – | 12,500 | 11,900 | Rupture of the CFRP sheet | |
| JI2 | 25.8 | 58 | – | – | 107.8 | 26.9 | 2163 | 2900 | 1740 | – | – | 13,000 | – | Rupture of the CFRP sheet | |
| Group #2 | JII0 | 25.9 | 10 | 32 | 50 | 70 | 20.4 | 971 | 1720 | 1413 | 1000 | – | – | – | De-bonding of main reinforcement |
| JII1 | 26.1 | 48 | 38 | 63 | 85 | 13.1 | 726 | 3301 | 1173 | 1110 | – | 8000 | – | Peeling off at the end of the CFRP sheets | |
| JII2 | 25.4 | 35 | – | 65 | 89.7 | 14.8 | 953 | 3542 | 1633 | 1190 | – | 8950 | – | Rupture of the CFRP sheet | |
| Group #3 | JIII0 | 25.3 | 10 | 40 | 50 | 65.1 | 15.2 | 629 | 1610 | 1220 | 850 | 1010 | – | – | Splitting flexural failure at the upper implanted column |
| JIII1 | 26.1 | 10 | 45 | 65 | 85.1 | 26.8 | 1762 | 3102 | 1091 | 1075 | 1450 | 10,500 | – | Peeling off at the end of CFRP plates | |
| JIII2 | 26.5 | 10 | 25 | 40 | 73.7 | 13.3 | 621 | 1750 | 1273 | 1010 | 1300 | 8020 | – | Peeling off at the end of CFRP sheets | |
| JIII3 | 25.8 | 10 | – | 42 | 66.2 | 20.4 | 989 | 1690 | 1260 | 890 | 1080 | 2000 | – | De-bonding of CFRP sheet followed by rupture of CFRP anchorage sheet | |
MS Beam: strain on the main steel of the beam, MS Column: strain on the tension main steel of the lower column, Column2: strain on tension main steel for the implanted upper column, FRP1: strain on the longitudinal direction of the strengthening CFRP, FRP2: strain on the horizontal CFRP sheet at the joint.