Investigation of the Flexural Behavior of Preloaded and Pre-Cracked Reinforced Concrete Beams Strengthened with CFRP Plates

S M Samindi M K Samarakoon; Bartosz Piatek; G H M J Subashi De Silva

doi:10.3390/ma16010022

Investigation of the Flexural Behavior of Preloaded and Pre-Cracked Reinforced Concrete Beams Strengthened with CFRP Plates

Materials (Basel). 2022 Dec 20;16(1):22. doi: 10.3390/ma16010022.

Authors

S M Samindi M K Samarakoon¹, Bartosz Piatek², G H M J Subashi De Silva³

Affiliations

¹ Department of Mechanical and Structural Engineering and Materials Science, Faculty of Science and Technology, University of Stavanger, 4021 Stavanger, Norway.
² Department of Roads and Bridges, Rzeszow University of Technology, 35-959 Rzeszów, Poland.
³ Department of Civil and Environmental Engineering, University of Ruhuna, Galle 8100, Sri Lanka.

Abstract

This paper investigates the flexural behavior of preloaded reinforced concrete (RC) beams, strengthened with Carbon Fiber Reinforced Polymer (CFRP) plates using an experimental program, analytical procedure, and Finite Element Method (FEM) simulation. The RC beams were subjected to preloads of 30%, 50% and 70% of the yielding load, prior to installation of the strengthening system. The eight RC-strengthened beams with a reinforcement configuration of 3Ø12 and two CarboDur S512 plates have been evaluated using bending tests. The failure modes of all the RC-strengthened beams were governed by the widening of flexural cracks within a constant bending zone, followed by debonding of the CFRP plates. The plates were debonding simultaneously or one plate prior to the other plate. The ultimate moment capacity is not significantly reduced while increasing preload levels from 0% to 70%. The moment capacity is increased by 70% to 80% in the CFRP strengthened beams, compared with un-strengthened beams indicating the potential of capacity enhancement that can be attained by externally bonded CFRP.

Keywords: CFRP; cracks; flexural strengthening; preload; reinforced concrete; ultimate moment.

Grants and funding

This research was funded by Department of Mechanical and Structural Engineering and Materials Science, Faculty of Science and Technology, University of Stavanger, Norway.