Experimental Study on Wedge Anchorage Performance of Prestressed BFRP Laminates for Flexural Strengthening of Reinforced Concrete Components
Publication: Journal of Composites for Construction
Volume 27, Issue 5
Abstract
This study investigated the anchoring effect of wedge anchorages on prestressed basalt fiber–reinforced polymer (BFRP) laminates. Compared with traditional carbon fiber–reinforced polymer (CFRP) laminates, BFRP laminates have a larger ultimate fracture strain, lower elastic modulus, and smaller prestress loss, making them cost-effective prestressed materials. Fifteen fiber-reinforced polymer (FRP) laminate–anchorage assemblies were prepared to investigate the effects of FRP type, anchorage type, mat type, and presetting load level on the static tensile behavior of FRP laminate–anchorage assemblies. The differences in the failure modes, load versus displacement (L–D) curves, and strain development of the FRP laminates were analyzed. The results demonstrated that, first, the anchorage efficiency of the CFRP laminate–anchorage assembly was higher than that of BFRP. Since the elastic modulus and transverse shear strength of the BFRP laminates were much lower than those of the CFRP laminates, the application of the traditional CFRP anchorage easily damaged the BFRP laminates. Therefore, a specific design and optimization are required for BFRP laminate anchorages. Second, an anchorage with a retracted stressing end wedge was prone to obtain higher normal stress and thus achieve a higher anchoring capacity. Third, the sandpaper mat improved the friction between the FRP laminate and wedges and alleviated the stress concentration phenomenon of the FRP laminate at the stressing end of the anchorage. Finally, an increased presetting load on the wedges could slightly improve the assemblies’ ultimate bearing capacity and stiffness; however, the enhanced presetting load aggravated the stress concentration phenomenon at the stressing end of the anchorage.
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Acknowledgments
This work was supported by the National Science Foundation of China (Grant No. 6305001037) and the Scientific Research Foundation of the Graduate School of Southeast University (Grant no. YBPY21).
Notation
The following symbols are used in this paper:
- b
- nominal width of the FRP laminate;
- bb0
- barrel width;
- bb1
- right width of the barrel;
- bb2
- middle width of the barrel;
- bb3
- left width of the barrel;
- E
- elastic modulus of the FRP laminate;
- Fu
- ultimate bearing capacity of the FRP laminate;
- fu
- ultimate tensile strength of the FRP laminate;
- hb0
- thickness of the barrel;
- hb1
- upper thickness of the barrel;
- hb2
- middle thickness of the barrel;
- hb3
- lower thickness of the barrel;
- hw
- thickness of the stressing end of the wedge;
- La
- length of the anchorage end;
- LFRP
- total length of the FRP laminate–anchorage assembly;
- Ls
- length of the strengthening plate end;
- Ltest
- length of the laminate without anchorage;
- lb0
- barrel length;
- lw0
- wedge length;
- lwe
- length of the wedge’s stressing end out of the barrel;
- length of the wedge’s free end out of the barrel;
- R
- stress ratio;
- t
- nominal thickness of the FRP laminate;
- αb
- slope angle of the barrel;
- αw
- slope angle of the wedge;
- strain at the measuring point;
- strain of strain gauge SG21;
- strain of strain gauge SG22;
- strain of strain gauge SG23;
- reference strain; and
- Δσ
- stress difference.
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Published In
Journal of Composites for Construction
Volume 27 • Issue 5 • October 2023
Copyright
© 2023 American Society of Civil Engineers.
History
Received: Dec 18, 2022
Accepted: May 12, 2023
Published online: Jul 11, 2023
Published in print: Oct 1, 2023
Discussion open until: Dec 11, 2023
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