Details
| Original language | English |
|---|---|
| Pages (from-to) | 156-172 |
| Number of pages | 17 |
| Journal | Composites Part B: Engineering |
| Volume | 155 |
| Publication status | Published - 15 Dec 2018 |
| Externally published | Yes |
Abstract
In this study, a novel retrofitting system is developed to strengthen existing metallic I-girders using prestressed unbonded carbon fiber reinforced polymer (CFRP) plates. The system relies on a pair of mechanical clamps. Each clamp holds two CFRP plates (each having cross-sectional dimensions of 50 × 1.4 mm) and anchors their prestressing forces to a metallic I-girder via friction. A finite element (FE) model was established to optimize the design of the required mechanical components, and a set of pull-off tests was performed to evaluate the capacity of the optimized system. The proposed flat prestressed unbonded retrofit (FPUR) system was then applied on a 6.4-m-long steel I-beam, and the excellent performance of the system, in terms of stress reduction in the beam bottom flange, was confirmed based on the results of a set of static four-point bending tests. Moreover, a fatigue four-point bending test was conducted on the steel I-beam, strengthened using the proposed FPUR system with a prestressing level of 53% (i.e., approximately 1120 MPa prestress in the CFRPs). Experimental results of the high-cycle fatigue test confirmed the excellent fatigue performance of the proposed FPUR system, as no prestress loss was observed after 20 million fatigue cycles. An analytical model is proposed to accurately predict the stress state in an I-girder strengthened with the proposed FPUR system, while design recommendations are provided concerning the practical use of the system. Relying on the laboratory experimental test results, the proposed FPUR system was used to strengthen the metallic cross-girders of a 121-year-old bridge in Australia.
Keywords
- Analytical modeling, Carbon fiber reinforced polymer, Fatigue, Finite element analysis (FEA), Flat prestressed unbonded retrofit (FPUR) system
ASJC Scopus subject areas
- Materials Science(all)
- Ceramics and Composites
- Engineering(all)
- Mechanics of Materials
- Engineering(all)
- Mechanical Engineering
- Engineering(all)
- Industrial and Manufacturing Engineering
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In: Composites Part B: Engineering, Vol. 155, 15.12.2018, p. 156-172.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Flat prestressed unbonded retrofit system for strengthening of existing metallic I-Girders
AU - Hosseini, Ardalan
AU - Ghafoori, Elyas
AU - Motavalli, Masoud
AU - Nussbaumer, Alain
AU - Zhao, Xiao Ling
AU - Al-Mahaidi, Riadh
N1 - Funding Information: 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 ). They would also like to thank the technicians of the Structural Engineering Research Laboratory of Empa for their exceptional cooperation in performing the experiments. Finally, support from S&P Clever Reinforcement Company AG, Switzerland, by providing the materials for the current study is acknowledged. Publisher Copyright: © 2018 Elsevier Ltd
PY - 2018/12/15
Y1 - 2018/12/15
N2 - In this study, a novel retrofitting system is developed to strengthen existing metallic I-girders using prestressed unbonded carbon fiber reinforced polymer (CFRP) plates. The system relies on a pair of mechanical clamps. Each clamp holds two CFRP plates (each having cross-sectional dimensions of 50 × 1.4 mm) and anchors their prestressing forces to a metallic I-girder via friction. A finite element (FE) model was established to optimize the design of the required mechanical components, and a set of pull-off tests was performed to evaluate the capacity of the optimized system. The proposed flat prestressed unbonded retrofit (FPUR) system was then applied on a 6.4-m-long steel I-beam, and the excellent performance of the system, in terms of stress reduction in the beam bottom flange, was confirmed based on the results of a set of static four-point bending tests. Moreover, a fatigue four-point bending test was conducted on the steel I-beam, strengthened using the proposed FPUR system with a prestressing level of 53% (i.e., approximately 1120 MPa prestress in the CFRPs). Experimental results of the high-cycle fatigue test confirmed the excellent fatigue performance of the proposed FPUR system, as no prestress loss was observed after 20 million fatigue cycles. An analytical model is proposed to accurately predict the stress state in an I-girder strengthened with the proposed FPUR system, while design recommendations are provided concerning the practical use of the system. Relying on the laboratory experimental test results, the proposed FPUR system was used to strengthen the metallic cross-girders of a 121-year-old bridge in Australia.
AB - In this study, a novel retrofitting system is developed to strengthen existing metallic I-girders using prestressed unbonded carbon fiber reinforced polymer (CFRP) plates. The system relies on a pair of mechanical clamps. Each clamp holds two CFRP plates (each having cross-sectional dimensions of 50 × 1.4 mm) and anchors their prestressing forces to a metallic I-girder via friction. A finite element (FE) model was established to optimize the design of the required mechanical components, and a set of pull-off tests was performed to evaluate the capacity of the optimized system. The proposed flat prestressed unbonded retrofit (FPUR) system was then applied on a 6.4-m-long steel I-beam, and the excellent performance of the system, in terms of stress reduction in the beam bottom flange, was confirmed based on the results of a set of static four-point bending tests. Moreover, a fatigue four-point bending test was conducted on the steel I-beam, strengthened using the proposed FPUR system with a prestressing level of 53% (i.e., approximately 1120 MPa prestress in the CFRPs). Experimental results of the high-cycle fatigue test confirmed the excellent fatigue performance of the proposed FPUR system, as no prestress loss was observed after 20 million fatigue cycles. An analytical model is proposed to accurately predict the stress state in an I-girder strengthened with the proposed FPUR system, while design recommendations are provided concerning the practical use of the system. Relying on the laboratory experimental test results, the proposed FPUR system was used to strengthen the metallic cross-girders of a 121-year-old bridge in Australia.
KW - Analytical modeling
KW - Carbon fiber reinforced polymer
KW - Fatigue
KW - Finite element analysis (FEA)
KW - Flat prestressed unbonded retrofit (FPUR) system
UR - http://www.scopus.com/inward/record.url?scp=85051488618&partnerID=8YFLogxK
U2 - 10.1016/j.compositesb.2018.08.026
DO - 10.1016/j.compositesb.2018.08.026
M3 - Article
AN - SCOPUS:85051488618
VL - 155
SP - 156
EP - 172
JO - Composites Part B: Engineering
JF - Composites Part B: Engineering
SN - 1359-8368
ER -