1. Home
  2. Vol 10, No 8 (2024)
  3. Varghese

Flexural Performance of Beams Strengthened with FRP Laminates and Alternative U-Wrap Anchors

Sneha M. Varghese, Kiran Kamath, Rajiv Selvam, Surumi Rasia Salim

Abstract


Premature debonding is identified as the main failure mode in reinforced concrete (RC) beams strengthened with externally bonded Fiber-Reinforced Polymer (FRP) laminates. This issue leads to the underutilization of FRP materials and needs to be addressed. Research has shown that end anchorage systems can effectively delay/mitigate delamination failures and enhance the performance of strengthened beams. FRP U-wraps are an effective means to prevent debonding failure; however, as open-form anchors, U-wraps cannot always guarantee complete resistance to debonding failures. This study proposes an alternative U-wrapping technique where the ends of the U-wraps are flared and inserted into the concrete substrate. The feasibility and effectiveness of this technique were studied by comparing it with conventional U-wraps. The experimental phase involved testing seven RC beams, each measuring 1.96×0.15×0.3 meters, under four-point bending. The results showed that the anchorage technique improved beam performance in terms of load-deflection behavior, failure modes, ductility, and FRP strain. Additionally, finite element simulations were conducted using Abaqus software to assess the effectiveness of the alternative U-wrap scheme. These models incorporated various nonlinear material constitutive laws, including cohesive zone modeling to replicate debonding failures at the CFRP-concrete interface. The numerical predictions were found to be in good agreement with the experimental test data.

 

Doi: 10.28991/CEJ-2024-010-08-01

Full Text: PDF


Keywords


Fiber Reinforced Polymer (FRP); Premature Debonding; Alternative U-Jackets; Finite Element Study; Abaqus.

References


El-Mandouh, M. A., Hu, J. W., Shim, W. S., Abdelazeem, F., & ELsamak, G. (2022). Torsional Improvement of RC Beams Using Various Strengthening Systems. Buildings, 12(11), 1776. doi:10.3390/buildings12111776.

Askar, M. K., Hassan, A. F., & Al-Kamaki, Y. S. S. (2022). Flexural and shear strengthening of reinforced concrete beams using FRP composites: A state of the art. Case Studies in Construction Materials, 17. doi:10.1016/j.cscm.2022.e01189.

Ceroni, F. (2010). Experimental performances of RC beams strengthened with FRP materials. Construction and Building Materials, 24(9), 1547–1559. doi:10.1016/j.conbuildmat.2010.03.008.

ACI 440.2R-17 (2017). Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures. American Concrete Institute (ACI), Michigan, United States. doi:10.14359/51700867.

Chalioris, C. E., Zapris, A. G., & Karayannis, C. G. (2020). U-jacketing applications of fiber-reinforced polymers in reinforced concrete t-beams against shear-tests and design. Fibers, 8(2), 13. doi:10.3390/fib8020013.

Elsayed, W. E., Ebead, U. A., & Neale, K. W. (2009). Studies on mechanically fastened fiber-reinforced polymer strengthening systems. ACI Structural Journal, 106(1), 49–59. doi:10.14359/56283.

Al-Atta, B., Kalfat, R., & Al-Mahaidi, R. (2022). Hybrid and patch anchors for prevention of IC debonding in RC planks flexurally strengthened using FRP. Structures, 43, 1042–1056. doi:10.1016/j.istruc.2022.07.026.

Sun, W., Liu, S., & Zhang, C. (2020). An effective improvement for enhancing the strength and feasibility of FRP spike anchors. Composite Structures, 247. doi:10.1016/j.compstruct.2020.112449.

Abdalla, J. A., Mhanna, H. H., Ali, A. B., & Hawileh, R. A. (2023). CFRP U-Wraps and Spike Anchors for Enhancing the Flexural Performance of CFRP-Plated RC Beams. Polymers, 15(7), 1621. doi:10.3390/polym15071621.

Chen, W., Pham, T. M., Sichembe, H., Chen, L., & Hao, H. (2018). Experimental study of flexural behaviour of RC beams strengthened by longitudinal and U-shaped basalt FRP sheet. Composites Part B: Engineering, 134, 114–126. doi:10.1016/j.compositesb.2017.09.053.

Al-Saawani, M. A., El-Sayed, A. K., & Al-Negheimish, A. I. (2022). Mitigation of Concrete Cover Separation in Concrete Beams Strengthened with Fiber-reinforced Polymer Composites. IOP Conference Series: Earth and Environmental Science, 1026(1), 12008. doi:10.1088/1755-1315/1026/1/012008.

Fu, B., Teng, J. G., Chen, J. F., Chen, G. M., & Guo, Y. C. (2017). Concrete Cover Separation in FRP-Plated RC Beams: Mitigation Using FRP U-Jackets. Journal of Composites for Construction, 21(2), 04016077. doi:10.1061/(asce)cc.1943-5614.0000721.

Al-Saawani, M. A., El-Sayed, A. K., Al-Negheimish, A. I., & Alhozaimy, A. M. (2024). FRP U-Wraps for Mitigating Plate-End Debonding in FRP-Strengthened Beams: Finite Element Modeling and Parametric Study. Arabian Journal for Science and Engineering, 49, 14001–14019. doi:10.1007/s13369-024-08853-6.

Fu, B., Tang, X. T., Li, L. J., Liu, F., & Lin, G. (2018). Inclined FRP U-jackets for enhancing structural performance of FRP-plated RC beams suffering from IC debonding. Composite Structures, 200, 36–46. doi:10.1016/j.compstruct.2018.05.074.

Al-Mahaidi, R., & Kalfat, R. (2018). FRP Anchorage Systems. Rehabilitation of Concrete Structures with Fiber-Reinforced Polymer, 331–376. doi:10.1016/b978-0-12-811510-7.00008-2.

Al-Saawani, M. A., El-Sayed, A. K., & Al-Negheimish, A. I. (2023). Inclined FRP U-Wrap Anchorage for Preventing Concrete Cover Separation in FRP Strengthened RC Beams. Arabian Journal for Science and Engineering, 48(4), 4879–4892. doi:10.1007/s13369-022-07186-6.

Dong, J., Wang, Q., & Guan, Z. (2013). Structural behaviour of RC beams with external flexural and flexural-shear strengthening by FRP sheets. Composites Part B: Engineering, 44(1), 604–612. doi:10.1016/j.compositesb.2012.02.018.

Ceroni, F., & Pecce, M. (2005). Ductility performance of RC beams strengthened with CFRP sheets. WIT Transactions on the Built Environment, 81, 579–589.

Ali, A., Abdalla, J., Hawileh, R., & Galal, K. (2014). CFRP mechanical anchorage for externally strengthened RC beams under flexure. Physics Procedia, 55, 10–16. doi:10.1016/j.phpro.2014.07.002.

Mostofinejad, D., Hosseini, S. M., Nader Tehrani, B., Eftekhar, M. R., & Dyari, M. (2019). Innovative warp and woof strap (WWS) method to anchor the FRP sheets in strengthened concrete beams. Construction and Building Materials, 218, 351–364. doi:10.1016/j.conbuildmat.2019.05.117.

Eslami, A., Shayegh, H. R., Moghavem, A., & Ronagh, H. R. (2019). Experimental and analytical investigations of a novel end anchorage for CFRP flexural retrofits. Composites Part B: Engineering, 176. doi:10.1016/j.compositesb.2019.107309.

Bank, L. C. (2013). Progressive Failure and Ductility of FRP Composites for Construction: Review. Journal of Composites for Construction, 17(3), 406–419. doi:10.1061/(asce)cc.1943-5614.0000355.

Xiao, Y., Chen, Z., Zhou, J., Leng, Y., & Xia, R. (2017). Concrete plastic-damage factor for finite element analysis: Concept, simulation, and experiment. Advances in Mechanical Engineering, 9(9), 1–10. doi:10.1177/1687814017719642.

Raza, A., Khan, Q. uz Z., & Ahmad, A. (2020). Prediction of Axial Compressive Strength for FRP-Confined Concrete Compression Members. KSCE Journal of Civil Engineering, 24(7), 2099–2109. doi:10.1007/s12205-020-1682-x.

Obaidat, Y. T., Heyden, S., & Dahlblom, O. (2010). The effect of CFRP and CFRP/concrete interface models when modelling retrofitted RC beams with FEM. Composite Structures, 92(6), 1391–1398. doi:10.1016/j.compstruct.2009.11.008.

Benzeggagh, M. L., & Kenane, M. (1996). Measurement of mixed-mode delamination fracture toughness of unidirectional glass/epoxy composites with mixed-mode bending apparatus. Composites Science and Technology, 56(4), 439–449. doi:10.1016/0266-3538(96)00005-x.

Esmaeili, J., Aghdam, O. R., Andalibi, K., Kasaei, J., & Gencel, O. (2022). Experimental and numerical investigations on a novel plate anchorage system to solve FRP debonding problem in the strengthened RC beams. Journal of Building Engineering, 45. doi:10.1016/j.jobe.2021.103413.

Mostafa, A. A. B., & Razaqpur, A. G. (2013). A new CFRP anchor for preventing separation of externally bonded laminates from concrete. Journal of Reinforced Plastics and Composites, 32(24), 1895–1906. doi:10.1177/0731684413498633.

Yahiaoui, D., Boutrid, A., Saadi, M., Mamen, B., & Bouzid, T. (2023). New Anchorage Technique for GFRP Flexural Strengthening of Concrete Beams Using Bolts-End Anchoring System. International Journal of Concrete Structures and Materials, 17(1), 20. doi:10.1186/s40069-023-00578-4.


Full Text: PDF

DOI: 10.28991/CEJ-2024-010-08-01

Refbacks

  • There are currently no refbacks.


Bookmark and Share


Copyright (c) 2024 Sneha Marium Varghese, Kiran Kamath, Rajiv Selvam, Surumi Rasia Salim

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
x
Message