Martin Noël

Fatigue Behavior of GFRP Reinforcing Bars in Air and in Concrete

Although the use of glass fiber-reinforced polymer (GFRP) reinforcing bars is gaining acceptance as an alternative to conventional steel reinforcement in concrete structures, little empirical data exist on the long-term fatigue performance of GFRP bars in concrete. Abrasion at the bar-concrete interface is known to have an adverse effect on bonds and on the overall member response under cyclic loading, although this effect was not adequately quantified until now. This paper presents the results of an experimental study comparing the fatigue performance of GFRP bars in air with the behavior of similar bars embedded in concrete. The experimental findings showed that the GFRP bars tested in air survived fatigue lives that were approximately a full order of magnitude longer than similar bars in concrete beams. The results were used to calibrate a statistical fatigue life model and a residual stiffness model for GFRP bars in reinforced concrete flexural members.

Effect of Prestressing on the Performance of GFRP-Reinforced Concrete Slab Bridge Strips

Deterioration of reinforced concrete structures caused by corrosion of steel reinforcement is currently a major concern affecting the safety and functionality of our infrastructure. Fiber-reinforced polymer (FRP) materials have shown tremendous potential as an alternative reinforcement for reinforced and prestressed concrete structures. FRPs have been used in a wide variety of structural applications, from reinforced concrete deck slabs to posttensioned parking garages. However, one promising application for FRP reinforcing bars which has yet to be investigated thoroughly is their use in reinforced concrete slab bridges. This paper presents the results of an experimental study on 10 full-scale glass FRP (GFRP)-reinforced slab bridge strips posttensioned with 0, 2, or 4 carbon FRP (CFRP) tendons with and without shear reinforcement. The tendons were either fully bonded or fully nonbonded to evaluate the effect of bond on the serviceability and ultimate performance of the slabs, particularly in terms of their deformability. Based on the test results, the addition of prestressed CFRP tendons resulted in significantly improved serviceability and ultimate load-carrying capacity with good deformability.

Evaluation of FRP Posttensioned Slab Bridge Strips Using AASHTO-LRFD Bridge Design Specifications

Deterioration of concrete structures caused by corrosion of steel reinforcement requires large capital investments in order to repair or replace existing structures which may or may not be nearing the end of their expected service lives. Fiber-reinforced polymer (FRP) reinforcement has emerged as a viable alternative to conventional reinforcement with lower life cycle costs. Serviceability typically governs the design of FRP structures because of the inherent low stiffness of FRP materials. As a result, concrete members tend to exhibit high deflections, large crack widths, and a reduction in shear capacity compared to similar steel-reinforced members. This study focuses on glass fiber–reinforced polymer (GFRP) reinforced slab strips cast with self-consolidating concrete (SCC) and posttensioned with carbon fiber–reinforced polymer (CFRP) tendons to improve the serviceability, shear capacity, and deformability of slab bridges. The flexural performance of five FRP slabs and one steel-reinforced control slab are compared to the design provisions of the AASHTO Load and Resistance Factor Design (LRFD) Bridge Design Specifications.

Design Equations for Concrete Bridge Decks with FRP Stay-in-Place Structural Forms

AbstractBridge deck construction using stay-in-place (SIP) fiber-reinforced polymer (FRP) structural forms has shown promise as an efficient, rapid, and low-waste alternative to conventional methods. Several studies have shown that the load capacity of this system is typically governed by punching shear strength, although no design-oriented equations have yet been developed to predict failure load or deflection at service. In this paper, two simple design equations are proposed for the ultimate load and stiffness of concrete deck slabs with SIP FRP forms, derived from the results of a comprehensive parametric study using a rigorous finite-difference computer model that is readily available. The equations were then validated by using experimental results from a database of 52 tests reported in the literature including FRP SIP forms of several shapes, sizes, surface treatments, spliced connections, boundary conditions, environmental exposures, and loading protocols. The equations showed an average predicted...

Fatigue Behavior of Full-Scale Slab Bridge Strips with FRP Reinforcement

AbstractWidespread deterioration of reinforced concrete (RC) bridge structures due to corrosion of steel reinforcement has resulted in an increased use of glass fiber-reinforced polymer (GFRP) reinforcing bars as an alternative reinforcement type for new bridge construction. Disadvantages of glass fiber-reinforced polymer reinforced concrete (GFRP-RC) flexural elements may include increased deflections and crack widths, significant reductions in the concrete contribution to shear resistance and susceptibility to fatigue failure. Posttensioned carbon fiber-reinforced polymer (CFRP) tendons can be used to effectively improve serviceability and shear resistance while increasing the fatigue life of the structure. An experimental study on the fatigue behavior of full-scale slab bridge strips with a reinforcement system combining passive GFRP reinforcing bars and active CFRP tendons is presented, along with analytical models to predict their fatigue lives and changes in stiffness resulting from repeated loading...

Fatigue Behavior of Reinforced Concrete Beams with Temperature Differentials at Room and Low Temperature

AbstractThis paper investigates the fatigue behavior of reinforced concrete beams at low temperatures compared to similar beams tested in fatigue at room temperature. Four large-scale steel-reinfor...

Behavior of Shear-Critical RC Beams Strengthened with CFRCM

AbstractStrengthening of RC structures using fiber-reinforced polymer (FRP) systems is a popular rehabilitation technique because of its ease of installation and reduced construction time compared ...