Experimental Study on Shear Performance of Concrete Beams Reinforced with Externally Unbonded Prestressed CFRP Tendons
To investigate the reinforcing effect of externally prestressed carbon-fiber-reinforced polymer (CFRP) tendons on the shear performance of reinforced concrete beams, a set of model tests was designed. Static load comparative tests were conducted on one original beam and four reinforced beams to expe...
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MDPI AG
2024-02-01
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| Online Access: | https://www.mdpi.com/2079-6439/12/3/23 |
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| author | Hetao Qi Haozhe Jiang Bing Wang Ping Zhuge |
| author_facet | Hetao Qi Haozhe Jiang Bing Wang Ping Zhuge |
| author_sort | Hetao Qi |
| collection | DOAJ |
| description | To investigate the reinforcing effect of externally prestressed carbon-fiber-reinforced polymer (CFRP) tendons on the shear performance of reinforced concrete beams, a set of model tests was designed. Static load comparative tests were conducted on one original beam and four reinforced beams to experimentally investigate the impacts of the prestress level and damage in the shear zone on the shear reinforcement effect and analyze the reinforcement mechanism of CFRP tendons. The results show that in the beams reinforced with CFRP, the CFRP tendons could work collaboratively with the stirrups to reduce the strain on the stirrups; the increasing rate in the yield load was 28–70%. After the stirrups yielded, the CFRP tendons did not yet reach their ultimate tensile strength and could still withstand increased shear forces, resulting in an increasing rate of the ultimate load for the reinforced beams with a CFRP content of 56–78%. The enhancements in both the yield load and the ultimate load were positively correlated with the level of prestress in the CFRP tendons. This reinforcement technique efficiently restricts the growth and delays the first appearance of diagonal cracks. The prestress can close the pre-existing diagonal cracks and provide a reserve of shear capacity for the beams. The initial damage in the shear zone decreases the initial shear stiffness and increases the width of the initial diagonal cracks. However, this effect gradually diminishes as the load increases and does not significantly impact the shear capacity. Prestressing can significantly improve the strength utilization rate of the CFRP reinforcement when the reinforced beams fail. The deformation of the CFRP tendon is directly related to the shear deformation. By combining this relationship with the truss–arch model, the shear capacity for the reinforced beam can be predicted. The predicted results exhibit an error of less than 10% when compared to the test results, offering valuable design guidance for reinforced engineering composites. |
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| institution | Directory Open Access Journal |
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| language | English |
| last_indexed | 2024-04-24T18:18:12Z |
| publishDate | 2024-02-01 |
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| spelling | doaj.art-8f5fc27fbfe645c5a62c3a509a74f1fa2024-03-27T13:38:04ZengMDPI AGFibers2079-64392024-02-011232310.3390/fib12030023Experimental Study on Shear Performance of Concrete Beams Reinforced with Externally Unbonded Prestressed CFRP TendonsHetao Qi0Haozhe Jiang1Bing Wang2Ping Zhuge3School of Civil & Environmental Engineering and Geography Science, Ningbo University, Ningbo 315211, ChinaSchool of Civil & Environmental Engineering and Geography Science, Ningbo University, Ningbo 315211, ChinaSchool of Civil & Environmental Engineering and Geography Science, Ningbo University, Ningbo 315211, ChinaSchool of Civil & Environmental Engineering and Geography Science, Ningbo University, Ningbo 315211, ChinaTo investigate the reinforcing effect of externally prestressed carbon-fiber-reinforced polymer (CFRP) tendons on the shear performance of reinforced concrete beams, a set of model tests was designed. Static load comparative tests were conducted on one original beam and four reinforced beams to experimentally investigate the impacts of the prestress level and damage in the shear zone on the shear reinforcement effect and analyze the reinforcement mechanism of CFRP tendons. The results show that in the beams reinforced with CFRP, the CFRP tendons could work collaboratively with the stirrups to reduce the strain on the stirrups; the increasing rate in the yield load was 28–70%. After the stirrups yielded, the CFRP tendons did not yet reach their ultimate tensile strength and could still withstand increased shear forces, resulting in an increasing rate of the ultimate load for the reinforced beams with a CFRP content of 56–78%. The enhancements in both the yield load and the ultimate load were positively correlated with the level of prestress in the CFRP tendons. This reinforcement technique efficiently restricts the growth and delays the first appearance of diagonal cracks. The prestress can close the pre-existing diagonal cracks and provide a reserve of shear capacity for the beams. The initial damage in the shear zone decreases the initial shear stiffness and increases the width of the initial diagonal cracks. However, this effect gradually diminishes as the load increases and does not significantly impact the shear capacity. Prestressing can significantly improve the strength utilization rate of the CFRP reinforcement when the reinforced beams fail. The deformation of the CFRP tendon is directly related to the shear deformation. By combining this relationship with the truss–arch model, the shear capacity for the reinforced beam can be predicted. The predicted results exhibit an error of less than 10% when compared to the test results, offering valuable design guidance for reinforced engineering composites.https://www.mdpi.com/2079-6439/12/3/23bridge engineeringexternal prestressingCFRP tendonsshear strengtheningshear capacitydiagonal cracks |
| spellingShingle | Hetao Qi Haozhe Jiang Bing Wang Ping Zhuge Experimental Study on Shear Performance of Concrete Beams Reinforced with Externally Unbonded Prestressed CFRP Tendons Fibers bridge engineering external prestressing CFRP tendons shear strengthening shear capacity diagonal cracks |
| title | Experimental Study on Shear Performance of Concrete Beams Reinforced with Externally Unbonded Prestressed CFRP Tendons |
| title_full | Experimental Study on Shear Performance of Concrete Beams Reinforced with Externally Unbonded Prestressed CFRP Tendons |
| title_fullStr | Experimental Study on Shear Performance of Concrete Beams Reinforced with Externally Unbonded Prestressed CFRP Tendons |
| title_full_unstemmed | Experimental Study on Shear Performance of Concrete Beams Reinforced with Externally Unbonded Prestressed CFRP Tendons |
| title_short | Experimental Study on Shear Performance of Concrete Beams Reinforced with Externally Unbonded Prestressed CFRP Tendons |
| title_sort | experimental study on shear performance of concrete beams reinforced with externally unbonded prestressed cfrp tendons |
| topic | bridge engineering external prestressing CFRP tendons shear strengthening shear capacity diagonal cracks |
| url | https://www.mdpi.com/2079-6439/12/3/23 |
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