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Performance of an EBR CFRP-strengthened RC slab using 24-h and cyclic load tests: a real case study

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Abstract

This study investigates the performance of a case study reinforced concrete (RC) slab strengthened in flexure with Fibre Reinforced Polymer (FRP) sheets. The RC slab is at the top floor of a 17-storey building upon which three water tanks (of 1,000 l each) had to be built due to a change of use of the building's top floor. To assess the performance of the existing slab, site investigations and non-destructive testing (NDT) were carried out as per ACI 318 standards. To increase the load capacity of the slab, Externally Bonded Reinforcement (EBR) Carbon FRP sheets were bonded to the bottom of the RC slab. Following the strengthening intervention, the CFRP-strengthened slab was subjected to a 24-h load test (according to ACI 318) and to a Cyclic Load Test (following ACI 437) using an ad-hoc water pool built on top of the slab. The results from these tests (maximum and residual deflections of 0.92 mm and 0.34 mm, respectively) indicated that the CFRP-strengthened slab met satisfactorily the deflection criteria and performance indices of such tests. The CFRP-strengthened slab was then modelled and analysed in ANSYS® to calibrate and validate the experimental results. It is shown that the deflection and strains predicted by the finite element (FE) model match well the experimental measurements (errors < 15%), which confirms the suitability of the modelling approach adopted in ANSYS®. This article contributes towards the dissemination of real case studies of FRP-strengthened structures, which are scarce in the literature and thus can be useful to engineers and practitioners working in the field of structural strengthening.

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Adopted from Wattanapanich et al. [32]

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Adopted from Wattanapanich et al. [32]

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No datasets were generated or analysed during the current study.

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Acknowledgements

This work was supported by Walailak University, Research Assistant Grant No. 38/2024. The authors acknowledge the partially support provided by the Capacity Enhancement and Driving Strategies for Bilateral and Multilateral Cooperation for 2021 (Thailand and UK). The authors also acknowledge the support from Ministry of Higher Education Malaysia, Fundamental Research Grant Scheme (FRGS), No: 9003-00965.

Funding

The authors would like to acknowledge the support from Ministry of Higher Education Malaysia, Fundamental Research Grant Scheme (FRGS), No: 9003-00965. The project was supported by the Capacity Enhancement and Driving Strategies for Bilateral and Multilateral Cooperation for 2021 (between Thailand and United Kingdom).

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Authors and Affiliations

  1. School of Engineering and Technology, Walailak University, Nakhon Si Thammarat, Thailand

    Radhika Sridhar, Pakjira Aosai & Thanongsak Imjai

  2. Civil Engineering Stream, School of Engineering, The University of Warwick, Coventry, UK

    Reyes Garcia

  3. Malaviya National Institute of Technology Jaipur, Jaipur, Rajasthan, India

    Anoop Shirkol

  4. School of Environmental Engineering, Universiti Malaysia Perlis, Perlis, Malaysia

    Nur Liza Rahim

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  1. Radhika Sridhar
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  2. Pakjira Aosai
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Contributions

R.S. and T.I.: Conceptualization, Methodology, Software, Investigation; T.I., R.S., R. G.: Methodology, Software, Validation, Writing—Original Draft, Writing—Review & Editing; T.I. N.L.R.: Conceptualization, Methodology, Formal analysis, Validation, Writing—Original Draft, Writing—Review & Editing, Visualization; T.I. N.L.R., P. A.: Writing—Original Draft, Visualization; All authors reviewed the manuscript.

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Correspondence to Thanongsak Imjai.

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Appendix 1. Visual inspection and rehabilitation work

Appendix 1. Visual inspection and rehabilitation work

Fig. 13
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Typical images of case study building at the time of site investigation

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Fig. 14
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Typical view of NDT performed on case study building

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Fig. 15
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View of instrumentation (a) LVDTs, (b) strain sensors, in-situ 24-h load test as per the ACI 318, and (c) water pool for load tests

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Sridhar, R., Aosai, P., Imjai, T. et al. Performance of an EBR CFRP-strengthened RC slab using 24-h and cyclic load tests: a real case study. J Build Rehabil 9, 85 (2024). https://doi.org/10.1007/s41024-024-00428-0

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