2019 CSCE Annual Conference - Laval (Greater Montreal)

2019 CSCE Annual Conference - Laval (Greater Montreal) Conference

Interpretation of Bond-Dependent Coefficient for Glass Fiber-Reinforced Polymer (GFRP) Bars

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Dr. Brahim Benmokrane, Universite de Sherbrooke (Presenter)
Mr. Paul Ballet
Dr. Khaled Mohamed, University of Sherbrooke

The bond-dependent coefficient (kb) is a key parameter for determining the crack width of the GFRP-reinforced concrete members. Many studies have been focusing on the bond behavior of GFRP bars, however, there is no consensus on the interpretations of the kb value.

The current study aims at interpreting the kb by assessing the available calculation procedures and recommending adequate service load and crack width limitations for the determination of the kb values. To achieve this objective, 20 full-scale GFRP-RC beams measuring 4250 mm long × 200 mm wide × 400 mm deep were tested to failure under four-point bending. The beams were reinforced longitudinally using GFRP bars of size #5, #6, and #8 produced by four different manufacturers (V-ROD, Aslan, ComBar, and MST-BAR). Specimens fabrications and testing procedure were following the test method recommended by CSA S806; Annex S. Each beam was replicated twice to reduce the dissidence between the results.  Results of this study showed that the kb value depended on the bar diameter and surface configuration and varied between 0.8 to 1.2 for all the beams. Stress-level approach and slope approach were used to interpret the kb, with the stress-level approach at serviceability limit of 30% of ultimate load produced feasible estimation for the crack width. Additionally, the calculated stresses using cracked section analysis were in acceptable agreement with the experimentally measured ones.