Strengthening of Damaged Reinforced Concrete Beams Using Externally Bonded Fiber Reinforced Polymer

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Title: Strengthening of Damaged Reinforced Concrete Beams Using Externally Bonded Fiber Reinforced Polymer

Author(s): Salah Altoubat, Abdul Saboor Karzad, Mohamed Maalej

Publication: Special Publication

Volume: 327

Issue:

Appears on pages(s): 28.1-28.12

Keywords: Damaged Beams, Epoxy Injection, FRP Strengthening, Repair, Shear strengthening

Date: 11/1/2018

Abstract:
This paper is part of an on-going research project on the behavior of damaged Reinforced Concrete (RC) beams repaired and strengthened with Externally Bonded Fiber Reinforced Polymer (EB-FRP). A total of seven full-scale rectangular beams; fully-damaged in a previous study, were repaired and retested to failure. The repair methodology consists of filling the cracks with epoxy, and then wrapping the beams with FRP discrete strips with two different thicknesses (1 layer and 2 layers). Out of the seven beams, four beams were strengthened using 2 layers of EB-FRP discrete strips; two beams were strengthened with 1 layer of EB-FRP; and the remaining beam was only repaired by crack injection with epoxy without wrapping with FRP. The beams were instrumented and tested to failure in three-points loading setup. The measured test parameters were the beams deflection and the maximum load-carrying capacity. Furthermore, the mode of failure was also observed and reported in this study. The test results revealed that the use of EB-FRP strips along with epoxy injection is an effective repair method that not only recovers the original strength (strength of the beams tested in previous study, considered as the reference beams), but also significantly increases their shear capacity. Comparing the shear capacity of the repaired beams to that of the reference beams, revealed that 2 layers of EB-FRP increased the shear strength by up to 95%, while the use of 1 layer of EB-FRP increased the shear strength by up to 66%. Moreover, comparison of the test results with existing predictive models (ACI 440.2R and fib TG-9.3) showed that both models reasonably predict the EB-FRP contribution to the shear strength of repaired and strengthened damaged beams.