Mechanics-based approach for predicting the short-term deflection of CFRP plated RC beams

Abstract

Most design codes available today for predicting the deflection of adhesively plated RC beams use a full-interaction moment-curvature approach that requires the flexural rigidity to be quantified empirically. Due to their empirical nature, these design rules can only be applied within the bounds of the tests from which they were derived. Furthermore, as these design rules follow a full-interaction analysis, the slip between the reinforcement and adjacent concrete was not considered and the method does not cope with the discrete rotation of the cracks; that is, the deflection associated with crack widening was not directly considered. As an alternative, partial-interaction mechanics-based methods can be used. In this study, a mechanics-based approach for quantifying the deflection of adhesively plated RC beams was presented. The approach took into account the slip between the reinforcement and adjacent concrete, the formation and widening of flexural cracks, and the intermediate crack debonding mechanism of the externally bonded plate. The deflection from the mechanics-based approach was determined by considering the discrete rotation of individual cracks and the curvature of uncracked regions of the beam. The deflection results derived from the mechanics-based approach were compared with the experimental results of seven adhesively plated CFRP RC beams bonded to their tension face and a significant correlation between the results was observed. The mechanics-based approach does not require any components on the member level to be quantified empirically; thus, it could be useful in predicting the deflection of adhesively plated RC beams with new types of reinforcement material.

Performances, challenges and opportunities in strengthening reinforced concrete structures by using FRPs – A state-of-the-art review

“…where is the ratio between the distance from the neutral axis to the fibre experiencing with negligible shear stress. The mechanics-based approach to evaluate the deflection behaviour of adhesively bonded FRP plate to RC beams were modelled in previous research, which accounts the slip between reinforcement and adjacent concrete [153]. Alternatively, the degradation observed under specific exposure conditions could be generalized by using the primary equation and adopting the appropriate coefficients.…”

Effect of the plate bondstress-slip property on the flexural strength of FRP Plated RC beams using a displacement-based approach

“…Moreover, the stress-strain response depicted in Fig. 5b was used to represent the constitutive relationship for the CFRP plate [3,22].…”

“…Quantifying the moment-rotation relationship of RC segments allowed researchers to come up with mechanics-based solutions to calculate the mid-span deflection of RC beams [19,20], non-prismatic RC beams [21] and FRP plated RC beams [22]. The research on partialinteraction design of RC structures progressed such that displacement-based mechanics solutions for predicting the flexural capacity of FRP plated RC beams were presented [11,23,24].…”

Flexural Behavior of Double-Skin Steel Tube Beams Filled with Fiber-Reinforced Cementitious Composite and Strengthened with CFRP Sheets

“…Project funding, often times, are significantly raised as a result of the strengthening practices for the present steel and composite structural parts by replacement and addition of new steel elements, because these repair works are time and capital intensive [ 13 ]. In recent years, engineers have made utilization of carbon fiber-reinforced polymer (CFRP) schemes for steel sections’ strengthening [ 12 , 13 , 14 ]. These schemes are suitable for resisting harsh weathers and possess high strength and elasticity compared with its weight ratio higher than those of the steel [ 15 ].…”