Figure 1.
(a) Scheme of the active anchorage. (b) Scheme of the tensioning device.
Figure 1.
(a) Scheme of the active anchorage. (b) Scheme of the tensioning device.
Figure 2.
Arrangement of the rivets, S1N–S2N, series’ specimens (NPS I).
Figure 2.
Arrangement of the rivets, S1N–S2N, series’ specimens (NPS I).
Figure 3.
Arrangement of the rivets, S3N–S5N, series’ specimens (NPS II).
Figure 3.
Arrangement of the rivets, S3N–S5N, series’ specimens (NPS II).
Figure 4.
Double-sided N-type anchorage of the NPS I system tested in the S1N–S2N series.
Figure 4.
Double-sided N-type anchorage of the NPS I system tested in the S1N–S2N series.
Figure 5.
Elements of the steel plates (a) and CFRP strips (b) prepared for bonding.
Figure 5.
Elements of the steel plates (a) and CFRP strips (b) prepared for bonding.
Figure 6.
Curing of the adhesive bonding in a heating device.
Figure 6.
Curing of the adhesive bonding in a heating device.
Figure 7.
One-sided N-type anchorage of the NPS II system tested in the S3N-S5N series.
Figure 7.
One-sided N-type anchorage of the NPS II system tested in the S3N-S5N series.
Figure 8.
Elements of the S4N series’ specimens prepared for bonding (longitudinal cut in the strip).
Figure 8.
Elements of the S4N series’ specimens prepared for bonding (longitudinal cut in the strip).
Figure 9.
Rivet upsetting using the hydraulic press.
Figure 9.
Rivet upsetting using the hydraulic press.
Figure 10.
Anchorage specimen installed in the testing machine jaws (a) and the testing machine (b).
Figure 10.
Anchorage specimen installed in the testing machine jaws (a) and the testing machine (b).
Figure 11.
Recording the failure mode using the speed video camera with a high framing rate and an example of the view.
Figure 11.
Recording the failure mode using the speed video camera with a high framing rate and an example of the view.
Figure 12.
Load-displacement plots for all the specimens in the S1N series.
Figure 12.
Load-displacement plots for all the specimens in the S1N series.
Figure 13.
Failure mode of the subsequent specimens in the S1N series: (a) P1/S1N, (b) P2/S1N, (c) P3/S1N.
Figure 13.
Failure mode of the subsequent specimens in the S1N series: (a) P1/S1N, (b) P2/S1N, (c) P3/S1N.
Figure 14.
Load-displacement plots for all the specimens in the S2N series.
Figure 14.
Load-displacement plots for all the specimens in the S2N series.
Figure 15.
Failure mode of the subsequent specimens in the S2N series: (a) P1/S2N, (b) P2/S2N, (c) P3/S2N.
Figure 15.
Failure mode of the subsequent specimens in the S2N series: (a) P1/S2N, (b) P2/S2N, (c) P3/S2N.
Figure 16.
Load-displacement plots for all the specimens in the S3N series.
Figure 16.
Load-displacement plots for all the specimens in the S3N series.
Figure 17.
Failure mode of the subsequent specimens in the S3N series: (a) P1/S3N, (b) P2/S3N, (c) P3/S3N.
Figure 17.
Failure mode of the subsequent specimens in the S3N series: (a) P1/S3N, (b) P2/S3N, (c) P3/S3N.
Figure 18.
Sequence of failure of specimen P3/S3N: (a) Specimen directly before failure, (b) longitudinal shear cracking and bottom part of the strip slipping out, resulting in carbon fiber overlay delamination, (c) specimen directly before the upper part of the strip slipping out, (d) upper part of the strip slipping out, (e) specimen after failure.
Figure 18.
Sequence of failure of specimen P3/S3N: (a) Specimen directly before failure, (b) longitudinal shear cracking and bottom part of the strip slipping out, resulting in carbon fiber overlay delamination, (c) specimen directly before the upper part of the strip slipping out, (d) upper part of the strip slipping out, (e) specimen after failure.
Figure 19.
Load-displacement plots for all the specimens in the S4N series.
Figure 19.
Load-displacement plots for all the specimens in the S4N series.
Figure 20.
Failure mode of the subsequent specimens in the S4N series: (a) P1/S4N, (b) P2/S4N, (c) P3/S4N.
Figure 20.
Failure mode of the subsequent specimens in the S4N series: (a) P1/S4N, (b) P2/S4N, (c) P3/S4N.
Figure 21.
Load-displacement plots for all the specimens in the S5N series.
Figure 21.
Load-displacement plots for all the specimens in the S5N series.
Figure 22.
Failure mode of the subsequent specimens in the S5N series: (a) P1/S5N, (b) P2/S5N, (c) P3/S5N.
Figure 22.
Failure mode of the subsequent specimens in the S5N series: (a) P1/S5N, (b) P2/S5N, (c) P3/S5N.
Figure 23.
Load-displacement plots for the specimens with the maximum failure load in the subsequent series.
Figure 23.
Load-displacement plots for the specimens with the maximum failure load in the subsequent series.
Figure 24.
Increasing of failure loads in subsequent test series.
Figure 24.
Increasing of failure loads in subsequent test series.
Figure 25.
Anchorage efficiency in the subsequent test series.
Figure 25.
Anchorage efficiency in the subsequent test series.
Table 1.
Differences between anchorages used in the NPS I and NPS II systems.
Table 1.
Differences between anchorages used in the NPS I and NPS II systems.
System | Test Series | Steel Plate Thickness | Adhesive Composition | Surface Treatment | Rivets |
---|
NPS I | S1N–S2N | 2 mm | standard | no treatment | 38 ϕ 4 mm, arranged according to Figure 2 |
NPS II | S3N–S5N | 3 mm | modified | sandblasting, chemical activator | 34 ϕ 4 mm, arranged according to Figure 3 |
Table 2.
Test results of the specimens tested in S1N series.
Table 2.
Test results of the specimens tested in S1N series.
Specimen | Failure Load | Mean Failure Load | Anchorage Efficiency | Mean Anchorage Efficiency | Failure Mode |
---|
(kN) | (kN) | (%) | (%) | - |
---|
P1/S1N | 91 | 110 | 40 | 48 | CFRP slip |
P2/S1N | 111 | 49 | CFRP slip |
P3/S1N | 129 | 56 | CFRP slip, longitudinal crack |
Table 3.
Summary of the loads resulting in the partial slip of the specimens tested in S1N series.
Table 3.
Summary of the loads resulting in the partial slip of the specimens tested in S1N series.
Specimen | Load at the First Partial Slip | Load at the First Partial Slip to Failure Load | Load at the Second Partial Slip | Load at the Second Partial Slip to Failure Load |
---|
(kN) | (%) | (kN) | (%) |
---|
P1/S1N | 51.3 | 57 | 63.1 | 70 |
P2/S1N | 67.5 | 61 | 79.1 | 71 |
P3/S1N | 61.2 | 47 | 60.2 | 47 |
Mean | 60.0 | 55 | 67.5 | 62 |
Table 4.
Test results of the specimens tested in S2N series.
Table 4.
Test results of the specimens tested in S2N series.
Specimen | Failure Load | Mean Failure Load | Anchorage Efficiency | Mean Anchorage Efficiency | Failure Mode |
---|
(kN) | (kN) | (%) | (%) | - |
---|
P1/S2N | 103 | 109 | 37 | 39 | CFRP slip |
P2/S2N | 120 | 43 | CFRP slip |
P3/S2N | 103 | 37 | CFRP slip |
Table 5.
Summary of the loads resulting in the partial slip of the specimens tested in S2N series.
Table 5.
Summary of the loads resulting in the partial slip of the specimens tested in S2N series.
Specimen | Load at the First Partial Slip | Load at the First Partial Slip to Failure Load | Load at the Second Partial Slip | Load at the Second Partial Slip to Failure Load |
---|
(kN) | (%) | (kN) | (%) |
---|
P1/S1N | 43.0 | 42 | - | - |
P2/S1N | 53.5 | 45 | - | - |
P3/S1N | 52.8 | 51 | 61.2 | 59 |
Mean | 49.8 | 46 | - | - |
Table 6.
Test results of the specimens tested in S3N series.
Table 6.
Test results of the specimens tested in S3N series.
Specimen | Failure Load | Mean Failure Load | Anchorage Efficiency | Mean Anchorage Efficiency | Failure Mode |
---|
(kN) | (kN) | (%) | (%) | - |
---|
P1/S3N | 126 | 145 | 46 | 52 | CFRP slip, longitudinal crack |
P2/S3N | 158 | 57 | CFRP slip, longitudinal crack |
P3/S3N | 152 | 55 | CFRP slip, longitudinal crack |
Table 7.
Test results of the specimens tested in S4N series.
Table 7.
Test results of the specimens tested in S4N series.
Specimen | Failure Load | Mean Failure Load | Anchorage Efficiency | Mean Anchorage Efficiency | Failure Mode |
---|
(kN) | (kN) | (%) | (%) | - |
---|
P1/S4N | 166 | 155 | 60 | 56 | CFRP slip, longitudinal crack |
P2/S4N | 144 | 52 | CFRP slip, longitudinal crack |
P3/S4N | 156 | 56 | CFRP slip, longitudinal crack |
Table 8.
Test results of the specimens tested in S5N series.
Table 8.
Test results of the specimens tested in S5N series.
Specimen | Failure Load | Mean Failure Load | Anchorage Efficiency | Mean Anchorage Efficiency | Failure Mode |
---|
(kN) | (kN) | (%) | (%) | - |
---|
P1/S5N | 177 | 185 | 64 | 67 | CFRP slip, longitudinal crack |
P2/S5N | 160 | 58 | CFRP slip, longitudinal crack |
P3/S5N | 217 | 79 | CFRP slip, partial rupture |
Table 9.
Summary of the test results in the subsequent test series.
Table 9.
Summary of the test results in the subsequent test series.
Test Series | Mean Failure Load | Mean Anchorage Efficiency | Standard Deviation | Variability Coefficient |
---|
(kN) | (%) | (kN) | (%) |
---|
S1N | 110 | 47 | 19.4 | 17.5 |
S2N | 109 | 39 | 9.6 | 8.8 |
S3N | 145 | 52 | 16.7 | 11.5 |
S4N | 155 | 56 | 11.4 | 7.3 |
S5N | 185 | 67 | 29.2 | 15.8 |