Universal Bond Models of FRP Reinforcements Externally Bonded and Near-Surface Mounted to RC Elements in Bending
The use of fibre-reinforced polymer materials (FRPs) for the retrofitting of reinforced concrete (RC) structures has become very popular. However, the main concern for the exploitation of FRPs is their premature debonding failure modes. This paper presents two different universal models for calculat...
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| Format: | Article |
| Language: | English |
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MDPI AG
2024-01-01
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| Series: | Materials |
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| Online Access: | https://www.mdpi.com/1996-1944/17/2/493 |
| _version_ | 1797343063884955648 |
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| author | Justas Slaitas |
| author_facet | Justas Slaitas |
| author_sort | Justas Slaitas |
| collection | DOAJ |
| description | The use of fibre-reinforced polymer materials (FRPs) for the retrofitting of reinforced concrete (RC) structures has become very popular. However, the main concern for the exploitation of FRPs is their premature debonding failure modes. This paper presents two different universal models for calculating flexed RC elements strengthened with externally bonded and near-surface mounted FRP reinforcements, which were derived by coupling principles of the fracture mechanics of solids and generally accepted assumptions. The first model allows a complete analysis of the behaviour, development, and propagation of rupture of the joint. The main advantages of the proposed model, compared to existing ones, are that it does not require additional bond shear tests to identify missing factors, and it is versatile and suitable for both externally bonded reinforcements (EBR) and near surface mounted (NSM) strengthening techniques. In addition, the concrete–FRP connection is divided into zones and the current phase and length of each zone are determined, allowing for more detailed analysis of the connection at different load stages. The proposed computational model and its derivation focus on the performance of the joint between the two cracks and the distribution of the shear stresses in that joint. The second one requires fewer computations and can be fully exploited when the joint is treated as a unit, without division. The results of the calculations have been validated using the experimental database of 77 RC beams and strengthened with externally bonded and near-surface mounted carbon fibre reinforced polymer (CFRP) and glass fibre reinforced polymer (GFRP) sheets, plates, strips, and bars taken from 13 different studies. Both the prestress force and the initial stress state before strengthening were evaluated. |
| first_indexed | 2024-03-08T10:42:17Z |
| format | Article |
| id | doaj.art-6a939dcc7b21478e9c5bb268e3fe13f2 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-08T10:42:17Z |
| publishDate | 2024-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-6a939dcc7b21478e9c5bb268e3fe13f22024-01-26T17:30:26ZengMDPI AGMaterials1996-19442024-01-0117249310.3390/ma17020493Universal Bond Models of FRP Reinforcements Externally Bonded and Near-Surface Mounted to RC Elements in BendingJustas Slaitas0Department of Reinforced Concrete Structures and Geotechnics, Vilnius Gediminas Technical University, Sauletekio Ave. 11, 10223 Vilnius, LithuaniaThe use of fibre-reinforced polymer materials (FRPs) for the retrofitting of reinforced concrete (RC) structures has become very popular. However, the main concern for the exploitation of FRPs is their premature debonding failure modes. This paper presents two different universal models for calculating flexed RC elements strengthened with externally bonded and near-surface mounted FRP reinforcements, which were derived by coupling principles of the fracture mechanics of solids and generally accepted assumptions. The first model allows a complete analysis of the behaviour, development, and propagation of rupture of the joint. The main advantages of the proposed model, compared to existing ones, are that it does not require additional bond shear tests to identify missing factors, and it is versatile and suitable for both externally bonded reinforcements (EBR) and near surface mounted (NSM) strengthening techniques. In addition, the concrete–FRP connection is divided into zones and the current phase and length of each zone are determined, allowing for more detailed analysis of the connection at different load stages. The proposed computational model and its derivation focus on the performance of the joint between the two cracks and the distribution of the shear stresses in that joint. The second one requires fewer computations and can be fully exploited when the joint is treated as a unit, without division. The results of the calculations have been validated using the experimental database of 77 RC beams and strengthened with externally bonded and near-surface mounted carbon fibre reinforced polymer (CFRP) and glass fibre reinforced polymer (GFRP) sheets, plates, strips, and bars taken from 13 different studies. Both the prestress force and the initial stress state before strengthening were evaluated.https://www.mdpi.com/1996-1944/17/2/493carbonglass fibre-reinforced polymerfracturedamagebond modelretrofitting |
| spellingShingle | Justas Slaitas Universal Bond Models of FRP Reinforcements Externally Bonded and Near-Surface Mounted to RC Elements in Bending Materials carbon glass fibre-reinforced polymer fracture damage bond model retrofitting |
| title | Universal Bond Models of FRP Reinforcements Externally Bonded and Near-Surface Mounted to RC Elements in Bending |
| title_full | Universal Bond Models of FRP Reinforcements Externally Bonded and Near-Surface Mounted to RC Elements in Bending |
| title_fullStr | Universal Bond Models of FRP Reinforcements Externally Bonded and Near-Surface Mounted to RC Elements in Bending |
| title_full_unstemmed | Universal Bond Models of FRP Reinforcements Externally Bonded and Near-Surface Mounted to RC Elements in Bending |
| title_short | Universal Bond Models of FRP Reinforcements Externally Bonded and Near-Surface Mounted to RC Elements in Bending |
| title_sort | universal bond models of frp reinforcements externally bonded and near surface mounted to rc elements in bending |
| topic | carbon glass fibre-reinforced polymer fracture damage bond model retrofitting |
| url | https://www.mdpi.com/1996-1944/17/2/493 |
| work_keys_str_mv | AT justasslaitas universalbondmodelsoffrpreinforcementsexternallybondedandnearsurfacemountedtorcelementsinbending |