Details
| Original language | English |
|---|---|
| Article number | 264 |
| Journal | Polymers |
| Volume | 10 |
| Issue number | 3 |
| Publication status | Published - 4 Mar 2018 |
| Externally published | Yes |
Abstract
Carbon fiber reinforced polymer (CFRP) composites have exhibited a great potential for strengthening of steel structures. In the current study, an innovative prestressed unbonded reinforcement (PUR) system is introduced for fatigue strengthening of existing steel members. The system relies on a pair of mechanical clamps; each holds multiple CFRP plates and anchors their prestressing forces to the steel substrate via friction. A finite element model was established to optimize the design of the required mechanical components of the system. A set of static and fatigue tests was conducted on the developed mechanical clamps as the key elements of the proposed PUR system. The performance of the PUR system was then evaluated using a set of fatigue tests on two precracked steel plate specimens, one without any strengthening system and the other one strengthened with the proposed PUR system. In the latter specimen, the CFRP plates were prestressed up to about 800 MPa (approximately 30% of the CFRP tensile strength), which resulted in a complete fatigue crack arrest in the precracked steel plate. Furthermore, neither slippage of the mechanical clamps nor any prestress loss in the CFRP plates was observed after 7.5 million fatigue cycles. Based on the promising experimental results, obtained from the sets of fatigue tests performed in the current study, it can be concluded that the proposed PUR system can be considered as an efficient alternative to the conventional bonded reinforcement solutions for fatigue strengthening of damaged steel members.
Keywords
- Carbon fiber reinforced polymer, Fatigue crack, Fatigue strengthening, Finite element simulation, Mechanical clamp, Prestressed unbonded reinforcement, Steel structures
ASJC Scopus subject areas
- Chemistry(all)
- General Chemistry
- Materials Science(all)
- Polymers and Plastics
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In: Polymers, Vol. 10, No. 3, 264, 04.03.2018.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Prestressed unbonded reinforcement system with multiple CFRP plates for fatigue strengthening of steel members
AU - Hosseini, Ardalan
AU - Ghafoori, Elyas
AU - Motavalli, Masoud
AU - Nussbaumer, Alain
AU - Zhao, Xiao Ling
AU - Koller, Roland
N1 - Funding Information: Acknowledgments: The authors gratefully acknowledge the financial support provided by the Swiss National Science Foundation (SNSF Project No. 200021-153609) and the Australian Research Council (ARC) Linkage Grant (LP140100543). The authors also would like to thank the technicians of the Central Workshop and the Mechanical Systems Engineering Laboratory of Empa for their exceptional cooperation in manufacturing the mechanical parts and performing the experiments. Support from S&P Clever Reinforcement Company AG, Switzerland, by providing the materials for the current study is acknowledged. Publisher Copyright: © 2018 by the authors.
PY - 2018/3/4
Y1 - 2018/3/4
N2 - Carbon fiber reinforced polymer (CFRP) composites have exhibited a great potential for strengthening of steel structures. In the current study, an innovative prestressed unbonded reinforcement (PUR) system is introduced for fatigue strengthening of existing steel members. The system relies on a pair of mechanical clamps; each holds multiple CFRP plates and anchors their prestressing forces to the steel substrate via friction. A finite element model was established to optimize the design of the required mechanical components of the system. A set of static and fatigue tests was conducted on the developed mechanical clamps as the key elements of the proposed PUR system. The performance of the PUR system was then evaluated using a set of fatigue tests on two precracked steel plate specimens, one without any strengthening system and the other one strengthened with the proposed PUR system. In the latter specimen, the CFRP plates were prestressed up to about 800 MPa (approximately 30% of the CFRP tensile strength), which resulted in a complete fatigue crack arrest in the precracked steel plate. Furthermore, neither slippage of the mechanical clamps nor any prestress loss in the CFRP plates was observed after 7.5 million fatigue cycles. Based on the promising experimental results, obtained from the sets of fatigue tests performed in the current study, it can be concluded that the proposed PUR system can be considered as an efficient alternative to the conventional bonded reinforcement solutions for fatigue strengthening of damaged steel members.
AB - Carbon fiber reinforced polymer (CFRP) composites have exhibited a great potential for strengthening of steel structures. In the current study, an innovative prestressed unbonded reinforcement (PUR) system is introduced for fatigue strengthening of existing steel members. The system relies on a pair of mechanical clamps; each holds multiple CFRP plates and anchors their prestressing forces to the steel substrate via friction. A finite element model was established to optimize the design of the required mechanical components of the system. A set of static and fatigue tests was conducted on the developed mechanical clamps as the key elements of the proposed PUR system. The performance of the PUR system was then evaluated using a set of fatigue tests on two precracked steel plate specimens, one without any strengthening system and the other one strengthened with the proposed PUR system. In the latter specimen, the CFRP plates were prestressed up to about 800 MPa (approximately 30% of the CFRP tensile strength), which resulted in a complete fatigue crack arrest in the precracked steel plate. Furthermore, neither slippage of the mechanical clamps nor any prestress loss in the CFRP plates was observed after 7.5 million fatigue cycles. Based on the promising experimental results, obtained from the sets of fatigue tests performed in the current study, it can be concluded that the proposed PUR system can be considered as an efficient alternative to the conventional bonded reinforcement solutions for fatigue strengthening of damaged steel members.
KW - Carbon fiber reinforced polymer
KW - Fatigue crack
KW - Fatigue strengthening
KW - Finite element simulation
KW - Mechanical clamp
KW - Prestressed unbonded reinforcement
KW - Steel structures
UR - http://www.scopus.com/inward/record.url?scp=85043264369&partnerID=8YFLogxK
U2 - 10.3390/polym10030264
DO - 10.3390/polym10030264
M3 - Article
AN - SCOPUS:85043264369
VL - 10
JO - Polymers
JF - Polymers
SN - 2073-4360
IS - 3
M1 - 264
ER -