Carbon Fiber Reinforced Polymer Surface Area and Bond Thickness Variation in Shear Strengthening of Reinforced Concrete Beam

International Journal of Civil Engineering

© 2022 by SSRG - IJCE Journal

Volume 9 Issue 3

Year of Publication : 2022

Authors : John A. Trust God, Osuji S. Obinna, Nwankwo Ebuka

10.14445/23488352/IJCE-V9I3P102

How to Cite?

John A. Trust God, Osuji S. Obinna, Nwankwo Ebuka, "Carbon Fiber Reinforced Polymer Surface Area and Bond Thickness Variation in Shear Strengthening of Reinforced Concrete Beam," SSRG International Journal of Civil Engineering, vol. 9,  no. 3, pp. 14-23, 2022. Crossref, https://doi.org/10.14445/23488352/IJCE-V9I3P102

Abstract:

This paper presents the results of carbon fibre reinforced polymer (CFRP) fabric surface area and bond thickness variation in shear strengthening of the reinforced concrete beam. Fifteen (15) single-span reinforced concrete beams with a span of 1100mm, and a cross-sectional area of 100mm x 150mm were subjected to static loading. Two 10mm and two 8mm diameter steels were provided at each beam sample's bottom and top. the depth of the internal steel reinforcement was 135mm. Two Carbon Fiber Wraps (also known as carbon fibre reinforced polymer fabric) of thickness 200g/m2 (0.111mm) and 300g/m2 (0.167mm) were bonded to the longitudinal axis on 1 side and 2-sides with 2mm, 4mm, 6mm, and 8mm adhesive thickness. the glue applied in this investigation was a mortar-like structural two-part Sikadur (R)-31 epoxy adhesive. 6 mm diameter shear links were introduced at 220 mm centre to centre in a constant moment region to ensure sliding failure developed in the shear region. One of the beams was a reference sample and not bonded with CFRP fabrics. the remaining samples were investigated to ascertain the response of various FRP surface areas and bond thickness variation to the shear strength of the beams. Each beam sample was supported and loaded with a two-point load positioned at one-third of the beam length. A hydraulic jack with a loading capacity of 200kN was used to apply the load. Vertical displacements at mid-span were measured using a dial gauge. the results show that the CFRP fabric to bond thickness ratio for RC beams strengthened along the longitudinal axis on 1-side and 2-sides should not be greater than 0.075; reinforced concrete beams strengthened along the longitudinal axis on both faces with the same surface area as the single face performed better than RCC strengthened on single. This improved performance can be ascribed to stress distribution via the bond on both sides rather than just one, which increases its shear capacity. Furthermore, beams strengthened with carbon fibre reinforced polymer fabric along the longitudinal axis lower stiffness while greatly reducing the surface area of CFRP while still reaching the requisite shear strength.

Keywords:

Bond thickness variation, CFRP Contribution to shear, Ductility index, FRP surface Area, Shear Strength, Shear strengthening.

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