Development of a Mechanical Wedge–Barrel Anchor for CFRP Rods: Static and Fatigue Behaviors
Publication: Journal of Composites for Construction
Volume 25, Issue 3
Abstract
In this study, a mechanical anchorage for prestressed carbon fiber–reinforced polymer (CFRP) rods was proposed. The proposed anchorage consisted of a steel barrel with a conical hole and three separate aluminum wedges that are in direct contact with the CFRP rod. The anchorage system relied only upon friction, without any adhesives required. The static and fatigue behaviors of the anchor were experimentally investigated according to the European guidelines for testing post-tensioning kits and fulfilled their requirements. The average tensile strength of the anchorage system for the 8-mm CFRP rods was 2,371.4 MPa, being greater than the guaranteed value of 2,047 MPa. The fatigue tests revealed that the wedge seating distance (prior to pulling the rod) significantly affected the occurrence of slippage between the anchor components. Therefore, a new displacement-controlled presetting system was developed to ensure adequate wedge seating distance. It eliminated the need for hydraulic jacks and demonstrated the capability of applying presetting forces greater than 110 kN. Furthermore, the anchors were tested under loading frequencies of 5, 17, and 23 Hz. The proposed anchorage was observed to be insensitive to the loading frequency because no slippage or temperature rise occurred under these loading frequencies.
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Data Availability Statement
All data and models from the experimental results and FE models that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
The authors acknowledge the Innosuisse Swiss Innovation Agency (Grant No. 19240.1 PFIW-IW) for funding this research project. The authors acknowledge the financial and technical support from the project partners, namely, S&P Clever Reinforcement Company AG, Switzerland; the Swiss Federal Railways (SBB) AG, Bern, Switzerland; and dsp Ingenieure + Planer AG Engineering Office, Uster, Switzerland.
Notation
The following symbols are used in this paper:
- Dr
- dial gauge reading for the CFRP rod;
- Dr,ref
- dial gauge reading for the CFRP rod in the reference state;
- Dw
- dial gauge reading for the wedges;
- Dw,ref
- dial gauge reading for the wedges in the reference state;
- f
- loading frequency;
- N
- number of cycles;
- P
- presetting force;
- S
- wedge seating distance;
- S61.9
- wedge seating distance at the lower fatigue load;
- T
- tensile load of the CFRP rod;
- Tnom
- nominal tensile strength of the CFRP rod;
- Tres
- residual tensile strength of the CFRP rod;
- Tu
- ultimate tensile strength of the CFRP rod;
- Δr
- relative draw-in of the CFRP rod; and
- Δw
- relative draw-in of the wedges.
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Published In
Journal of Composites for Construction
Volume 25 • Issue 3 • June 2021
Copyright
© 2021 American Society of Civil Engineers.
History
Received: Sep 15, 2020
Accepted: Feb 19, 2021
Published online: Mar 23, 2021
Published in print: Jun 1, 2021
Discussion open until: Aug 23, 2021
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