Influence of Externally Bonded CFRP on the Shear Behavior of Strengthened and Rehabilitated Reinforced Concrete T-Beams Containing Shear Stirrups
Abstract
:1. Introduction
1.1. Literature Overview
1.2. Paper Objectives and Significance
2. Materials and Methods
2.1. Material Properties
2.1.1. Concrete and Steel
2.1.2. CFRP
2.1.3. Epoxy Resin (Adhesive)
2.2. Test Specimens
2.2.1. Specimen Details
2.2.2. Test Groups
2.3. Strengthening and Rehabilitation Process
2.4. Test Setup
3. Theoretical Calculations
4. Results and Discussion
4.1. General Behavior and Failure Modes
4.2. Experimental Shear Capacity
4.3. Experimental Load–Deflection Behavior
4.4. Theoretical Results
5. Conclusions
- The results clearly indicate that using externally bonded CFRP laminates and sheets in T-beams is effective in improving the shear capacity.
- For the strengthening and rehabilitation of RC T-beams, the failure to be expected is either pure shear cracks propagated to the tension face of the T-beam, CFRP debonding failure, or CFRP rapture failure associated with cover separation.
- The shear capacity increased for the strengthened T-beams by a range of 26–100%. The highest increase was recorded for the horizontal CFRP strips scheme.
- The shear capacity increased for the preloaded T-beams by a range of 21–73%. The highest increase was recorded for the horizontal CFRP strips scheme.
- The capacities of the strengthened beams were higher than those of their corresponding preloaded T-beams; however, there was no big difference between the experimental results of the strengthening and rehabilitation of T-beams as long as the preloaded T-beams were not loaded with more than 60% of their design capacity. After loading the beams up to 60% of the ultimate load, the dial gauge returned to zero deflection and all beams returned to their initial condition; thus, it is concluded that no significant damage occurred.
- For the experimental load–deflection curves, all T-beams exhibited almost linear trends with different slopes.
- The deflection recorded with the use of CFRP was lower than that of the control T-beam at any load values; however, the deflection at failure was not always lower than that of the control T-beam.
- The ACI 440.2R−17 does not differ between the strengthening and rehabilitation of T-beams. Moreover, not all the parameters are considered logically in the calculations; thus, the theoretical results are not always conservative in predicting the shear capacity and the provisions need to be revised.
- The theoretically predicted values according to the ACI 440.2R−17 and the experimental results did not have the same pattern of ordering the highest capacities.
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
- Abdel-Jaber, M.S.; Walker, P.R.; Hutchinson, A.R. Shear strengthening of reinforced concrete beams using different configurations of externally bonded carbon fibre reinforced plates. Mater. Struct. 2003, 36, 291–301. [Google Scholar] [CrossRef]
- Rasheed, H.A.; Decker, B.R.; Esmaeily, A.; Peterman, R.J.; Melhem, H.G. The Influence of CFRP Anchorage on Achieving Sectional Flexural Capacity of Strengthened Concrete Beams. Fibers 2015, 3, 539–559. [Google Scholar] [CrossRef] [Green Version]
- Al-Khafaji, A.; Salim, H. Flexural Strengthening of RC Continuous T-Beams Using CFRP. Fibers 2020, 8, 41. [Google Scholar] [CrossRef]
- Triantafillou, T.C. Shear Strengthening of Reinforced Concrete Beams Using Epoxy-Bonded FRP Composites. ACI Struct. J. 1998, 95, 107–115. [Google Scholar]
- Abdel-Jaber, M. Shear Strengthening of Reinforced Concrete Beams Using Externally Bonded Carbon Fibre Reinforced Plates. Ph.D. Thesis, Oxford Brookes University, Oxford, UK, 2001. [Google Scholar]
- Teng, J.G.; Smith, S.T.; Yao, J.; Chen, J.F. Intermediate Crack-induced De-bonding in RC Beams and Slabs. Constr. Build. Mater. 2003, 17, 447–462. [Google Scholar] [CrossRef]
- Chen, J.-F.; Teng, J. Shear capacity of FRP-strengthened RC beams: FRP debonding. Constr. Build. Mater. 2003, 17, 27–41. [Google Scholar] [CrossRef]
- Bousselham, A.; Chaallal, O. Shear Strengthening Reinforced Concrete Beams with Fiber-Reinforced Polymer: Assessment of Influencing Parameters and Required Research. ACI Struct. J. 2004, 101, 219–227. [Google Scholar]
- Zhang, Z.; Hsu, C.-T.T. Shear Strengthening of Reinforced Concrete Beams Using Carbon-Fiber-Reinforced Polymer Laminates. J. Compos. Constr. 2005, 9, 158–169. [Google Scholar] [CrossRef]
- Adhikary, B.B.; Mutsuyoshi, H. Shear strengthening of reinforced concrete beams using various techniques. Constr. Build. Mater. 2006, 20, 366–373. [Google Scholar] [CrossRef]
- Barros, J.A.O.; Dias, S.J.E.; Lima, J.L.T. Efficacy of CFRP-based techniques for the flexural and shear strengthening of concrete beams. Cem. Concr. Compos. 2007, 29, 203–217. [Google Scholar] [CrossRef]
- Hafez, A.M.A. Shear Behavior of RC Beams Strengthened Externally with Bonded CFRP–U Strips. J. Eng. Sci. 2007, 35, 361–379. [Google Scholar]
- Abdel-Jaber, M.; Shatanawi, A.S.; Abdel-Jaber, M.S. Guidelines for Shear Strengthening of Beams Using Carbon Fiber-Reinforced Polymer (FRP) Plates. Jordan J. Civ. Eng. 2007, 1, 327–335. [Google Scholar]
- Bukhari, I.; Vollum, R.; Ahmad, S.; Sagaseta, J. Shear strengthening of reinforced concrete beams with CFRP. Mag. Concr. Res. 2010, 62, 65–77. [Google Scholar] [CrossRef] [Green Version]
- Godat, A.; Qu, Z.; Lu, Z.X.; Labossiere, P.; Ye, L.P.; Neale, K.W. Size Effects for Reinforced Concrete Beams Strengthened in Shear with CFRP Strips. J. Compos. Constr. 2010, 14, 260–271. [Google Scholar] [CrossRef]
- Al-Tersawy, S.H. Effect of fiber parameters and concrete strength on shear behavior of strengthened RC beams. Constr. Build. Mater. 2013, 44, 15–24. [Google Scholar] [CrossRef]
- Alsayed, S.H.; Siddiqui, N.A. Reliability of shear-deficient RC beams strengthened with CFRP-strips. Constr. Build. Mater. 2013, 42, 238–247. [Google Scholar] [CrossRef]
- Mostofinejad, D.; Hosseini, S.A.; Razavi, S.B. Influence of different bonding and wrapping techniques on performance of beams strengthened in shear using CFRP reinforcement. Constr. Build. Mater. 2016, 116, 310–320. [Google Scholar] [CrossRef]
- Ibrahim, A.M.; Mansor, A.A.; Hameed, M. Structural Behavior of Strengthened RC Beams in Shear using CFRP Strips. Open Civ. Eng. J. 2017, 11, 205–215. [Google Scholar] [CrossRef] [Green Version]
- Al-Ghanim, H.; Al-Asi, A.; Abdel-Jaber, M.; Alqam, M. Shear and Flexural Behavior of Reinforced Concrete Deep Beams Strengthened with CFRP Composites. Mod. Appl. Sci. 2017, 10, 110–122. [Google Scholar] [CrossRef] [Green Version]
- Abdel-Jaber, M.; Abdel-Jaber, M.; Katkhuda, H.; Shatarat, N.; El-Nimri, R. Influence of Compressive Strength of Concrete on Shear Strengthening of Reinforced Concrete Beams with Near Surface Mounted Carbon Fiber-Reinforced Polymer. Buildings 2021, 11, 563. [Google Scholar] [CrossRef]
- Chalioris, C.E.; Kosmidou, P.-M.K.; Papadopoulos, N.A. Investigation of a New Strengthening Technique for RC Deep Beams Using Carbon FRP Ropes as Transverse Reinforcements. Fibers 2018, 6, 52. [Google Scholar] [CrossRef] [Green Version]
- Chajes, M.J.; Januszka, T.F.; Mertz, D.R.; Thomson, T.A.; Finch, W.W. Shear strengthening of Reinforced Concrete beams using externally applied composite fabrics. ACI Struct. J. 1995, 92, 295–303. [Google Scholar]
- Khalifa, A.; Nanni, A. Improving shear capacity of existing RC T-section beams using CFRP composites. Cem. Concr. Compos. 2000, 22, 165–174. [Google Scholar] [CrossRef]
- Tanarslan, H.M.; Altin, S. Behavior of RC T-section beams strengthened with CFRP strips, subjected to cyclic load. Mater. Struct. 2009, 43, 529–542. [Google Scholar] [CrossRef]
- Bae, W.; Belarbi, A.; Brancaccio, A. Shear strengthening of full-scale RC T-Beams using externally bonded CFRP sheets. In Proceedings of the First Middle East Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures, Dubai, United Arab Emirates, 8–10 February 2011. [Google Scholar]
- Kim, Y.; Quinn, K.; Ghannoum, W.; Jirsa, J. Strengthening of Reinforced Concrete T-Beams Using Anchored CFRP Materials. ACI Struct. J. 2012, 111, 1–6. [Google Scholar] [CrossRef]
- Soliman, J. General behavior of T-section RC beams strengthened with Epoxy-Bonded carbon strands. MOJ Civil Eng. 2018, 4, 213–217. [Google Scholar] [CrossRef]
- El-Saikaly, G.; Godat, A.; Chaall, O. New Anchorage Technique for FRP Shear-Strengthened RC T-Beams Using CFRP Rope. J. Compos. Constr. 2015, 19, 04014064. [Google Scholar] [CrossRef]
- Mhanna, H.H.; Hawilehb, R.A.; Abdallac, J.A. Shear Strengthening of Reinforced Concrete Beams Using CFRP Wraps. Procedia Struct. Integr. 2019, 17, 214–221. [Google Scholar] [CrossRef]
- Benzeguir, Z.E.A.; El-Saikaly, G.; Chaallal, O. Size Effect of RC T-Beams Strengthened in Shear with Externally Bonded CFRP L-Shaped Laminates. J. Compos. Constr. 2020, 24, 04020031. [Google Scholar] [CrossRef]
- Tanarslan, H.M.; Yalçınkaya, Ç.; Alver, N.; Karademir, C. Shear strengthening of RC beams with externally bonded UHPFRC laminates. Compos. Struct. 2021, 262, 113611. [Google Scholar] [CrossRef]
- Kuntal, V.S.; Chellapandian, M.; Prakash, S.S.; Sharma, A. Experimental Study on the Effectiveness of Inorganic Bonding Materials for Near-Surface Mounting Shear Strengthening of Prestressed Concrete Beams. Fibers 2020, 8, 40. [Google Scholar] [CrossRef]
- Chalioris, C.E.; Zapris, A.G.; Karayannis, C.G. U-Jacketing Applications of Fiber-Reinforced Polymers in Reinforced Concrete T-Beams against Shear—Tests and Design. Fibers 2020, 8, 13. [Google Scholar] [CrossRef] [Green Version]
- Hassan, S.K.H.; Abdel-Jaber, M.S.; Alqam, M. Rehabilitation of Reinforced Concrete Deep Beams Using Carbon Fiber Reinforced Polymers (CFRP). Mod. Appl. Sci. 2018, 12, 179. [Google Scholar] [CrossRef]
- Jayaprakash, J.; Samad, A.A.A.; Ashrabov, A.A.; Choong, K.K. Experimental Investigation on Shear Resistance Behaviour of RC Precracked and Non Precracked T-Beams using Discrete CFRP Strips. Int. J. Integr. Eng. 2009, 1, 1–15. [Google Scholar]
- ACI Committee 440. ACI 440.2R-17: Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures; American Concrete Institute (ACI): Farmington Hills, MI, USA, 2017; pp. 1–8. [Google Scholar]
- ACI Committee 318. Building Code Requirements for Structural Concrete (ACI 318-19)—Commentary on Building Code Requirements for Structural Concrete (ACI 318R-19); American Concrete Institute (ACI): Farmington Hills, MI, USA, 2019; p. 261. [Google Scholar]
Requirement | Result (%) | Standard Values | ||
---|---|---|---|---|
Min | Max | Min | Max | |
Fineness (Blaine) (cm2/g) | 4500 | 5000 | ||
Soundness (mm) | 0.5 | 2 | 10 | |
Initial setting time (min) | 130 | 165 | 60 |
Cement (kg/m3) | Water (kg/m3) | Coarse Aggregates (kg/m3) | Fine Aggregates (kg/m3) |
---|---|---|---|
375 | 180 | 1042.97 | 754.178 |
Tested Average Yield Stress (MPa) | Tested Average Ultimate Stress (MPa) | Elastic Modulus (GPa) | Elongation |
---|---|---|---|
550 | 680 | 200 | 14 |
Property | MasterBrace LAM | MasterBrace FIP |
---|---|---|
Modulus of elasticity (GPa) | >210 | 230 |
Tensile strength (GPa) | >2.8 | 4.9 |
Density (g/cm3) | 1.6 | 1.76 |
Thickness (mm) | 1.4 | 0.166 |
Property | Value | |
---|---|---|
Compressive Strength at 25 °C (BS 6319 part 2) | day 1 | 40 MPa |
day 7 | 65 MPa | |
Flexural strength at 25 °C (ASTM C 580 part 7) | day 7 | 20 MPa |
Tensile Strength at 25 °C (BS 6319 Part 7) | day 7 | 10 MPa |
Pot life in Minutes | at 25 °C | 50 |
at 40 °C | 30 | |
Recoat time in Hours | at 25 °C | 8 |
at 40 °C | 6 | |
Bond Strength | <2 MPa (concrete failure) | |
Setting time at 25 °C | 12 h | |
Meets the requirements of ASTM C881 Type 1 Grade 3 Class B & C |
Property | Value | |
---|---|---|
Product Chemistry | MasterBrace® SAT 4500 Part A | Epoxy Resin |
MasterBrace® SAT 4500 Part B | Epoxy Hardener | |
Color | Blue | |
Mixed density | 1.02 kg/liter | |
Viscosity | 1500–2500 mPa·s | |
Compressive strength TS EN 196 (7 days) | >60 MPa | |
Flexural strength TS EN 196 (7 days) | >50 MPa | |
Bonding strength to concrete (7 days) | >3.0 N/MPa | |
Pot life | 30 min | |
Fully cured at 20 °C | 7 days |
Label | Definition |
---|---|
CB | Control sample: T-beam with no CFRP attached |
S-Inc | T-beam strengthened with 45° inclined CFRP attached |
R-Inc | T-beam preloaded with 45° inclined CFRP attached |
S-Str | T-beam strengthened with horizontal straight strips of CFRP attached |
R-Str | T-beam preloaded with horizontal straight strips of CFRP attached |
S-Sh | T-beam strengthened with U-wrap CFRP sheets attached |
R-Sh | T-beam preloaded with U-wrap CFRP sheets attached |
Sample | Experimental Shear Capacity (kN) | Increase (%) | |
---|---|---|---|
CB | 160 | 0% | |
S-Inc1 | 195 | 22% | 26% |
S-Inc2 | 207 | 29% | |
S-Inc3 | 204 | 28% | |
R-Inc1 | 200 | 25% | 21% |
R-Inc2 | 193 | 21% | |
R-Inc3 | 186 | 16% | |
S-Str1 | 320 | 100% | 100% |
S-Str2 | 317 | 98% | |
S-Str3 | 324 | 103% | |
R-Str1 | 279 | 74% | 73% |
R-Str2 | 285 | 78% | |
R-Str3 | 268 | 68% | |
S-Sh1 | 225 | 41% | 41% |
S-Sh2 | 219 | 37% | |
S-Sh3 | 232 | 45% | |
R-Sh1 | 205 | 28% | 28% |
R-Sh2 | 199 | 24% | |
R-Sh3 | 211 | 32% |
Sample | Experimental Shear Capacity (kN) | Theoretical Shear Capacity (kN) | Percent Increase (%) | |
---|---|---|---|---|
CB | 160 | 157.6 | 1% | |
S-Inc1 | 195 | 231.2 | −19% | −15% |
S-Inc2 | 207 | 231.2 | −12% | |
S-Inc3 | 204 | 231.2 | −13% | |
R-Inc1 | 200 | 231.2 | −16% | −20% |
R-Inc2 | 193 | 231.2 | −20% | |
R-Inc3 | 186 | 231.2 | −24% | |
S-Str1 | 320 | 308.9 | 3% | 4% |
S-Str2 | 317 | 308.9 | 3% | |
S-Str3 | 324 | 308.9 | 5% | |
R-Str1 | 279 | 308.9 | −11% | −11% |
R-Str2 | 285 | 308.9 | −8% | |
R-Str3 | 268 | 308.9 | −15% | |
S-Sh1 | 225 | 217.5 | 3% | 3% |
S-Sh2 | 219 | 217.5 | 1% | |
S-Sh3 | 232 | 217.5 | 6% | |
R-Sh1 | 205 | 217.5 | −6% | −6% |
R-Sh2 | 199 | 217.5 | −9% | |
R-Sh3 | 211 | 217.5 | −3% |
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Abdel-Jaber, M. Influence of Externally Bonded CFRP on the Shear Behavior of Strengthened and Rehabilitated Reinforced Concrete T-Beams Containing Shear Stirrups. Fibers 2021, 9, 87. https://doi.org/10.3390/fib9120087
Abdel-Jaber M. Influence of Externally Bonded CFRP on the Shear Behavior of Strengthened and Rehabilitated Reinforced Concrete T-Beams Containing Shear Stirrups. Fibers. 2021; 9(12):87. https://doi.org/10.3390/fib9120087
Chicago/Turabian StyleAbdel-Jaber, Mu’tasime. 2021. "Influence of Externally Bonded CFRP on the Shear Behavior of Strengthened and Rehabilitated Reinforced Concrete T-Beams Containing Shear Stirrups" Fibers 9, no. 12: 87. https://doi.org/10.3390/fib9120087