1 Introduction
2 Strengthening Evaluation Test Specimen Details
Quality | Dimension | Scale factor |
---|---|---|
Length | M | S |
Mass | M | S3 |
Force | MLT−2 | S2 |
Stress | ML−1 T−2 | 1 |
Velocity | LT−1 | 1 |
Acceleration | LT−2 | S−1 |
Time | T | S |
Quality | Target column | Circular cross-sectional column specimen | Similarity | Rectangular cross-sectional column specimen |
---|---|---|---|---|
Section (mm) | Diameter | Diameter | Length × breadth | |
1200 | 600 | 2 | 540 × 680 | |
Height (mm) | 6100 | 2900 | 2.10 | 2900 |
Geometry ratio | 5.08 | 5.08 | 1 | 5.08 |
Axial load (ton) | 155 | 38.75 | 2 | 38.75 |
Longitudinal reinforcing bar (mm) | D25 = 25.4 | D13 = 12.7 | 2 | D13 = 12.7 |
Ratio of reinforcement | 0.016129 | 0.016132 | 0.99, 1.01 | 0.015872 |
Hoop reinforcing bar (mm) | D13 = 12.7 | D10 = 9.53 | 1.33 | D10 = 9.53 |
Spacing of hoop (mm) | S = 300 | S = 150 | 2 | S = 150 |
2.1 Half-Scale Model Column Specimen Details
2.2 One-Sixth Scale Model Column Specimen Details
Quality | Target column | Circular cross-sectional column specimen | Similarity | Rectangular cross-sectional column specimen |
---|---|---|---|---|
Section (mm) | Diameter | Diameter | Length × breadth | |
1200 | 600 | 2 | 540 × 680 | |
Height (mm) | 6100 | 1025 | 5.95 | 1025 |
Axial load (ton) | 155 | 4.305 | 6 | 4.305 |
Longitudinal reinforcing bar (mm) | D25 = 25.4 | D10 = 9.53 | 2.66 | D10 = 9.53 |
Ratio of reinforcement | 0.016129 | 0.01817 | 0.88, 0.90 | 0.01801 |
Hoop reinforcing bar (mm) | D13 = 12.7 | D10 = 9.53 | 1.33 | D10 = 9.53 |
Spacing of hoop (mm) | S = 300 | S = 75 | 4 | S = 75 |
2.3 STPU and GFPU-Strengthening Details
Properties | STPU | Concrete | Rebar | Tendon |
---|---|---|---|---|
Drying time (s) | 20 | – | – | – |
Tensile strength (MPa) | 26 | 2.8 | 400 | 1600 |
Shore hardness (D) | 70 | – | – | – |
Bond strength (MPa) | 14 | – | – | – |
Percent elongation | 150 | – | – | – |
Compressive strength (MPa) | – | 30 | – | – |
Specimen | Cross-section type | Strengthened type | Test |
---|---|---|---|
C-RC | Circular | RC | Quasi-static |
C-RC | Circular | RC | Pseudo-dynamic |
R-RC | Rectangular | RC | Pseudo-dynamic |
C-PU | Circular | STPU 5 mm | Pseudo-dynamic |
R-PU | Rectangular | STPU 5 mm | Pseudo-dynamic |
C-GFPU | Circular | GFPU (GFRP + STPU) 5 mm | Pseudo-dynamic |
R-GFPU | Rectangular | GFPU (GFRP + STPU) 5 mm | Pseudo-dynamic |
Specimen | Cross-section type | Strengthened type | Test |
---|---|---|---|
C-RC | Circular | RC | Shaking table |
R-RC | Rectangular | RC | Shaking table |
C-PU | Circular | STPU 5 mm | Shaking table |
R-PU | Rectangular | STPU 5 mm | Shaking table |
C-GFPU | Circular | GFPU (GFRP + STPU) 5 mm | Shaking table |
R-GFPU | Rectangular | GFPU (GFRP + STPU) 5 mm | Shaking table |
2.4 Data Measurement Details
2.4.1 Pseudo-dynamic Test Specimen
2.4.2 Shaking Table Test Specimen
3 Quasi-static Test
3.1 Half-Scale Model Column Specimen Details
4 Pseudo-dynamic Test
4.1 Test Results and Discussion
4.1.1 Force Versus Displacement Curve and Relative Displacement
Specimen | PMax (kN) | Displacement (mm) | Relative displacement (mm) | Ratio |
---|---|---|---|---|
C-RC | − 208.63 | − 69.48 | 124.00 | 1.00 |
174.51 | 54.52 | |||
C-PU | − 173.59 | − 72.15 | 118.51 | 0.96 |
188.79 | 46.36 | |||
C-GFPU | − 188.37 | − 69.48 | 114.99 | 0.93 |
180.49 | 45.51 | |||
R-RC | − 224.62 | − 67.60 | 105.89 | 1.00 |
224.07 | 38.29 | |||
R-PU | − 218.09 | − 63.53 | 100.06 | 0.94 |
210.10 | 36.53 | |||
R-GFPU | − 253.13 | − 60.56 | 96.18 | 0.91 |
207.29 | 35.62 |
4.1.2 Rebar Strains
Specimen | PMax (kN) | Reinforcement strain (× 10–6) | Ratio |
---|---|---|---|
C-RC | − 208.63 | 15,813.94 | 1.00 |
174.51 | 2266.68 | 1.00 | |
C-PU | − 173.59 | 8986.20 | 0.57 |
188.79 | 1912.69 | 0.84 | |
C-GFPU | − 188.37 | 15,933.99 | 1.00 |
180.49 | 1643.11 | 0.72 | |
R-RC | − 224.62 | 3503.03 | 1.00 |
224.07 | 1079.27 | 1.00 | |
R-PU | − 218.09 | 2998.34 | 0.85 |
210.10 | 800.11 | 0.74 | |
R-GFPU | − 253.13 | 3344.37 | 0.95 |
207.29 | 841.81 | 0.77 |
Applied load (kN) | Push | Pull | ||||
---|---|---|---|---|---|---|
RC (MPa) | PU (MPa) | GFPU (MPa) | RC (MPa) | PU (MPa) | GFPU (MPa) | |
0 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
10 | 47.38 | 19.61 | 23.66 | 34.63 | 29.31 | 28.14 |
20 | 64.46 | 35.61 | 38.36 | 90.86 | 68.89 | 50.64 |
30 | 114.42 | – | 47.88 | 121.36 | 121.67 | 93.46 |
40 | 131.51 | 63.08 | – | 170.89 | 160.38 | 136.50 |
50 | 152.71 | 82.76 | 68.86 | 211.12 | 194.77 | 174.14 |
60 | 171.09 | 92.71 | – | 286.60 | 224.83 | 228.86 |
70 | 190.56 | 97.90 | 89.19 | 325.54 | 259.22 | 252.86 |
80 | 213.92 | 115.21 | 109.96 | 364.03 | 299.45 | 296.34 |
90 | 232.52 | 133.37 | 126.18 | 413.78 | 332.98 | 332.24 |
100 | 246.36 | 149.38 | 140.88 | 464.39 | 367.15 | 369.23 |
110 | 274.48 | 162.79 | 152.35 | 513.71 | 401.76 | 400.16 |
120 | 296.11 | 191.34 | 164.68 | 567.13 | 426.20 | 420.27 |
130 | 312.11 | 208.64 | 188.47 | 642.83 | 465.35 | 459.85 |
140 | 332.01 | 225.51 | 207.72 | 702.52 | 516.61 | 497.70 |
150 | 358.40 | 257.09 | 224.80 | 766.33 | 527.20 | 576.00 |
160 | 413.77 | 273.10 | 247.30 | 826.46 | 540.61 | 595.46 |
170 | 464.16 | 290.83 | 275.63 | 892.21 | 597.71 | 608.66 |
Applied load (kN) | Push | Pull | ||||
---|---|---|---|---|---|---|
RC (MPa) | PU (MPa) | GFPU (MPa) | RC (MPa) | PU (MPa) | GFPU (MPa) | |
0 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
10 | 13.73 | 14.68 | 14.15 | 29.68 | 14.83 | 7.25 |
20 | 37.52 | 20.95 | – | 56.72 | 40.35 | 28.01 |
30 | 49.42 | – | – | 74.24 | 72.15 | 55.27 |
40 | 60.02 | 38.68 | 34.91 | 104.52 | 97.67 | – |
50 | – | – | 42.05 | – | 108.26 | 89.66 |
60 | 79.27 | – | – | 137.40 | 134.00 | 116.26 |
70 | – | 55.77 | 53.95 | 167.03 | 170.99 | 132.05 |
80 | 98.08 | 63.13 | – | 194.50 | – | – |
90 | 109.33 | 70.05 | 69.52 | 204.44 | 199.97 | 165.57 |
100 | 117.98 | 81.73 | 78.60 | 221.75 | 220.95 | – |
110 | 131.83 | 88.86 | 82.06 | 257.00 | 236.74 | 198.02 |
120 | 142.86 | 91.24 | 90.93 | 288.58 | 270.26 | 223.75 |
130 | 147.61 | 100.11 | 99.37 | 318.43 | 302.49 | 241.71 |
140 | 155.83 | 107.46 | 110.61 | 338.54 | 328.66 | 256.85 |
150 | 166.21 | 112.01 | 117.10 | – | 343.15 | 289.72 |
160 | 172.05 | 118.28 | 127.27 | 377.91 | 367.59 | 320.00 |
170 | 179.19 | 127.58 | 132.89 | 411.21 | 398.31 | 344.01 |
180 | 188.28 | 132.99 | 142.62 | 441.28 | 422.96 | 363.69 |
190 | 198.87 | 142.07 | 149.54 | 474.80 | 463.62 | 395.49 |
200 | 207.09 | 151.59 | 160.79 | 491.02 | 501.47 | 424.47 |
210 | 217.69 | 159.37 | 168.36 | 579.49 | 573.50 | 445.88 |
4.1.3 Displacement Ductility
Specimen | Load direction | PMax (kN) | Displ. (mm) | Yield displ. (mm) | Displ. ductility | Normalized displ. ductility |
---|---|---|---|---|---|---|
C-RC | Push | 174.51 | 54.52 | 47.26 | 1.15 | 1.00 |
Pull | − 208.63 | − 69.48 | − 61.18 | 1.14 | 1.00 | |
C-PU | Push | 188.79 | 46.36 | 34.69 | 1.34 | 1.16 |
Pull | − 173.59 | − 72.15 | − 43.03 | 1.68 | 1.48 | |
C-GFPU | Push | 180.49 | 45.51 | 32.39 | 1.41 | 1.22 |
Pull | − 188.37 | − 69.48 | − 44.61 | 1.56 | 1.37 | |
R-RC | Push | 224.07 | 38.29 | 31.93 | 1.20 | 1.00 |
Pull | − 224.62 | − 67.60 | − 40.18 | 1.68 | 1.00 | |
R-PU | Push | 210.10 | 36.53 | 27.58 | 1.32 | 1.10 |
Pull | − 218.09 | − 63.53 | − 40.64 | 1.56 | 0.93 | |
R-GFPU | Push | 207.29 | 35.62 | 28.54 | 1.25 | 1.04 |
Pull | − 253.13 | − 60.56 | − 40.74 | 1.49 | 0.88 |
4.1.4 Dissipation Energy
Specimen | Dissipation energy (kN mm) | Ratio |
---|---|---|
C-RC | 6828.68 | 1.00 |
C-PU | 10,425.61 | 1.53 |
C-GFPU | 10,379.11 | 1.52 |
R-RC | 12,292.94 | 1.00 |
R-PU | 10,201.87 | 0.83 |
R-GFPU | 9153.05 | 0.74 |
5 Shaking Table Test
5.1 Test Results and Discussion
5.1.1 Displacement Versus Time Curve
Specimen | Shaking table (mm) | Column head (mm) | Relative displ. (mm) | Range of relative displ. (mm) | Ratio |
---|---|---|---|---|---|
C-RC | 136.55 | 139.97 | 12.96 | 24.06 | 1.00 |
− 103.39 | − 107.46 | − 11.10 | |||
C-PU | 112.84 | 118.37 | 8.59 | 15.82 | 0.66 |
− 116.26 | − 117.86 | − 7.23 | |||
C-GFPU | 127.56 | 133.14 | 7.43 | 12.40 | 0.52 |
− 107.72 | − 107.36 | − 4.97 | |||
R-RC | 134.00 | 140.17 | 7.49 | 12.41 | 1.00 |
− 105.40 | − 105.96 | − 4.92 | |||
R-PU | 134.59 | 138.86 | 5.57 | 7.63 | 0.65 |
− 105.10 | − 104.55 | − 2.06 | |||
R-GFPU | 134.49 | 137.41 | 4.92 | 6.71 | 0.54 |
− 104.75 | − 104.70 | − 1.79 |
5.1.2 Rebar Strain Versus Time Curve
Specimen | Reinforcement strain (× 10–6) | Range of strain (× 10–6) | Ratio |
---|---|---|---|
C-RC | 2420 | 3650 | 1.00 |
− 1230 | |||
C-PU | 1630 | 2170 | 0.59 |
− 540 | |||
C-GFPU | 620 | 960 | 0.26 |
− 340 | |||
R-RC | 1200 | 1690 | 1.00 |
− 490 | |||
R-PU | 330 | 580 | 0.34 |
− 250 | |||
R-GFPU | 300 | 510 | 0.30 |
− 210 |