Polymer Reinforced Concrete Beams Research Articles

Comprehensive analysis of bond stress transfer mechanisms in glass fiber-reinforced polymer-reinforced concrete beams using acoustic emission monitoring

The present study investigates the critical bond characteristics between glass fiber-reinforced polymer (GFRP) bars, which is essential for the application bars as corrosion-resistant components in structural concrete. The interfacial bond deterioration and stress transfer mechanisms have been investigated in the present study by employing acoustic emission (AE) monitoring in hinged-type GFRP-reinforced concrete (GFRP-RC) beam specimens. The bond strength of the test specimens, governed by chemical adhesion, mechanical interlocking, and frictional resistance, has been intricately examined. Various AE signal parameters as well as historic and severity indices derived from the AE signal parameters have been meticulously evaluated and correlated with bond stress and rebar slip variations. The present study has also introduced an innovative approach of using the sentry function for the assessment of bond deterioration and associated mechanisms. The results of the present study demonstrate the reliability of AE parameters in monitoring debonding and bond strength variation, the effectiveness of the sentry function in evaluating damage progression, and the utility of historic and severity indices in capturing micro-mechanism transformations. The accurate localization of debonding and the qualitative distribution of bond stress have also been demonstrated by through correlations between cumulative AE parameters and rebar slip, Additionally, the present study also highlights the significance of peak frequency variations in AE signals, serving as a crucial tool for quantifying the mechanical interlocking and interfacial friction. The results contribute significantly to precise assessments and development of effective strategies for mitigating bond deterioration in GFRP-RC elements.

Theoretical Model for Calculating Shear Strength of Fiber-Reinforced Polymer-Reinforced Concrete Beams

Theoretical Model for Calculating Shear Strength of Fiber-Reinforced Polymer-Reinforced Concrete Beams

Modified Shear Design Model for Steel- and Fiber- Reinforced Polymer-Reinforced Concrete Beams

Modified Shear Design Model for Steel- and Fiber- Reinforced Polymer-Reinforced Concrete Beams

Evaluating Behavior of Shear-Critical Glass Fiber- Reinforced Polymer-Reinforced Concrete Beams

Evaluating Behavior of Shear-Critical Glass Fiber- Reinforced Polymer-Reinforced Concrete Beams

Design and Detailing of Glass Fiber-Reinforced Polymer-Reinforced Concrete Beams according to ACI CODE-440.11-22

Design and Detailing of Glass Fiber-Reinforced Polymer-Reinforced Concrete Beams according to ACI CODE-440.11-22

Experimental investigation and numerical simulation of the flexural behavior of reinforced concrete beams strengthened by geopolymer-bonded CFRP

PurposeA numerical simulation of the test beam was carried out with Abaqus and compared with test data to ensure that the modeling method is accurate. An analysis of the effects of the angle between the U-hoop and horizontal direction, the pre-crack height, the pre-crack spacing, and the strength of the geopolymer adhesive on the cracking load and ultimate load of the reinforced beam is presented.Design/methodology/approachLoad tests and finite element simulations were conducted on carbon fiber reinforced polymer-reinforced concrete beams bonded with geopolymer adhesive. The bond-slip effect of geopolymer adhesive was taken into account in the model. The flexural performances, the flexural load capacities, the deformation capacities, and the damage characteristics of the beams were observed, and the numerical simulation results were in good agreement with the experimental results. An analysis of parametric sensitivity was performed using finite element simulation to investigate the effects of different angles between U-hoop and horizontal direction, pre-crack heights, pre-crack spacing, and strength of geopolymer adhesive on cracking load and ultimate load.FindingsUnder the same conditions, the higher the height of the pre-crack, the lower the bearing capacity; increasing the pre-crack spacing can delay cracking, but reduce ultimate load. By increasing the strength of the geopolymer adhesive, the flexural resistance of the beam is improved, and crack development is also delayed; the angle between the u-hoop and horizontal direction does not affect the cracking of reinforced beams; a horizontal u-hoop has a better effect than an oblique u-hoop, and 60° is the ideal angle between the u-hoop and horizontal direction for better reinforcement.Originality/valueAccording to the experimental study in this paper, Abaqus was used to simulate the strength of different angles between U-hoop and horizontal direction, pre-crack heights, pre-crack spacings, and geopolymer adhesives, and the angles' effects on the cracking load and load carrying capacity of test beams were discussed. Since no actual tests are required, the method is economical. This paper offers data support for the promotion and application of environmentally friendly reinforcement technology, contributes to environmental protection, and develops a new method for reinforcing reinforced concrete beams and a new concept for finite element simulations.

Reliability-Based Design Recommendations for Deflection Control of Fiber-Reinforced Polymer-Reinforced Concrete Beams

Reliability-Based Design Recommendations for Deflection Control of Fiber-Reinforced Polymer-Reinforced Concrete Beams

The influence of FRP bars and reinforcement ratio on bending for FRP-reinforced concrete beams

The flexural property of the fibre-reinforced polymer-reinforced concrete beams was simulated by the correct selection of element model, material constitutive relation and failure criteria based on the finite element analysis software ABAQUS. The simulation result fits the real test result very well. The feasibility of the modelling method was verified by the test result of selected models, The bending and failure stage of the fibre-reinforced polymer-reinforced concrete beams was divided by the further analysis, and the performance was compared with the normal reinforced concrete beams. By non-linear numerical simulation, the reinforcement ratio and the fibre type were analysed to test the performance of the fibre-reinforced polymer-reinforced concrete beams.

Nonlinear finite element analyses of steel/FRP-reinforced concrete beams in fire conditions

In this paper, a simple one-dimensional two-node layered composite beam element is developed for accurate modeling of structural behavior of steel/fiber reinforced polymer-reinforced concrete beams under a combined mechanical and thermal loading in fire conditions. By employing the Timoshenko’s beam functions to construct the new element, shear-locking problem is avoided naturally and a unified formulation for analyses of both slender and moderately deep beams is established. A nonlinear finite element analysis based on heat transfer theory is performed to determine the temperature distribution across the cross section of the beam. Both geometric and temperature-dependent material nonlinearities are accounted for. The element is computationally effective, and is demonstrated to be efficient and accurate. The element is easily employed to investigate the influences of a series of parameters on the structural behavior of FRP-reinforced concrete beams in fire conditions, which could provide useful references for structural analysis and design.

Ductility Demand of Compression Yielding Fiber-Reinforced Polymer-Reinforced Concrete Beams

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Prediction of Crack Width for Fiber-Reinforced Polymer-Reinforced Concrete Beams

Use of fiber-reinforced polymer (FRP) bars to replace steel in reinforced concrete structures is being encouraged by many structural engineers, especially for its noncorrosive properties. The partial inferiority of the bond and mechanical properties for few commercial FRP bars, however, leads to wider, deeper cracks compared with those of steel-reinforced concrete structures. The characteristics of such cracks have significant interaction with the stresses and displacements induced in the concrete and the reinforcing bars crossing the crack (dowel action of bars), as well as on the contribution of the stirrups at crack location. Furthermore, because the dowel failure of FRP bars takes place in a brittle mode and lower magnitude of transverse displacement than steel, an accurate prediction of these characteristics is essential for a proper evaluation of beam serviceability, as well as its strength and failure conditions. Therefore, this paper presents an analytical formula that calculates the maximum crack width in FRP-reinforced concrete beams, taking into account both the bond and the mechanical properties of FRP bars.

Effective Moment of Inertia for Glass Fiber-Reinforced Polymer-Reinforced Concrete Beams

This paper investigates deflection behavior of concrete flexural members reinforced with glass fiber-reinforced polymer (GFRP) reinforcing bars. It is recognized that serviceability plays a major role in the design of GFRP-reinforced concrete beams. Therefore, accurate modeling of flexural stiffness is critical and the effect of influencing parameters must be considered. This study accounts for variations in concrete strength, reinforcement density, and shear span-depth ratio. Experimental results from 48 simply supported concrete beams reinforced with GFRP are compared with ACI Committee 440's published deflection model. The ACI 440.1R model is found to overestimate the effective moment of inertia, and an appropriate modification is presented.

Fatigue strength in polymer-reinforced concrete beams under cyclic loading

This research focuses on producing an inexpensive polymer, and also on experiments for producing various colors of the high strength polymer concrete in concrete structures. At present, only a few tests on the shear behavior of polymer-reinforced concrete (PRC) beams have been reported. Even fewer experiments on fatigue loading have been carried out to date. In the current experiments, reinforced concrete beams with a polymer fraction are investigated. The beams in this study are reinforced with conventional stirrups at appropriate intervals, and are designed to take static and fatigue loads. The strength of the beams is measured and the behavior of the beams under each loading are observed to determine the advantages of adding a polymer to reinforced concrete beams. Since the shear-fatigue behavior of PRC beams is not well understood, the appropriate limit state model of PRC beams subjected to shear-fatigue loading is developed in this research by incorporating the uncertainties which are assessed based on fatigue test results. Using specimens of reinforced concrete or PRC beams with and without stirrups, compression and split cylinder tests, as well as fatigue tests, were performed. The static test data consist of load, displacement and strain measurements at specified reinforcement locations. In this study, mean regression S N curves are obtained to investigate the shear-fatigue characteristics that the test results are distributed over a wide fatigue life range at the same fatigue load level but, in general, the mean shear-fatigue strength of PRC beams with stirrups is higher than for PRC beams without stirrups. In the static tests, it has been observed that the beams have the same fracture modes as those of reinforced concrete. In the fatigue tests, the PRC beams were observed to perform rather poorly with regard to impact load, but it can be said that the increase in strength and excellent repair performance of the beams were verified. Consequently, this work strongly suggests that steam curing or air curing must be used to increase the strength.