Analytical study of the section of the rc beams strengthened for flexure with FRP materials (original) (raw)
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Experimental and Analytical Study on Reinforced Concrete Beams in Bending Strengthened with FRP
The Open Construction and Building Technology Journal, 2014
The performance of the interface between fiber reinforced polymer (FRP) composites and concrete is one of the key factors affecting the behavior of strengthened reinforced concrete (RC) structures. Existing laboratory research has shown that RC beams strengthened with FRP sheets usually fail because of either debonding of the impregnated fabric from the concrete substrate or fracture of the FRP. This work presents an experimental and analytical investigation of the effectiveness of FRP strengthening sheets on RC beams aiming at increasing their flexural strength and stiffness. Experimental results obtained from beam specimens tested under four-point bending are examined with main parameters being the resin type and the anchoring system. In addition, the procedure suggested by the EC8 - Greek Assessment & Retrofitting Code (EC8-GARC) provisions is applied and compared with the experimental results.
Experimental and Analytical Investigation of FRP Reinforced Concrete Beams in Flexure
Engineering Research Journal (Shoubra), 2023
Rebars fabricated from Fiber-Reinforced Polymers (FRP) are innovative materials utilized as an alternative to traditional steel reinforcement rebars in reinforced concrete structures to overcome corrosion problems especially in harsh and aggressive environments. FRP rebars manufactured from glass or basalt fibers embedded in a polymer matrix have high tensile strength, stiffness and enhanced durability. Also, FRP rebars have moderate costs. This research investigates experimentally the flexural performance of FRP-reinforced concrete beams. In the experimental program, two concrete beams reinforced by glass and basalt FRP bars were tested under a four-point flexural test until failure. Both the failure load, the failure mechanism and the mid-span deflection of the tested beams are presented and discussed. The experimental investigation showed that the major failure mode of the tested beams reinforced by FRP bars is crushing of concrete at the top substrate. Additionally, theoretical analysis of the ultimate flexural capacity and the failure loads were computed using American design guidelines and were found to be in good agreement with the experimental results.
2018
In this paper presents an experimental study conducted to examine the effectiveness of Fibre Reinforced Polymer (FRP) composites in enhancing the flexural capacity of concrete beams. In this study, Fibrereinforced polymer (FRP) application is a very effective way to repair and strengthen structures that have become structurally weak over their lifespan. Externally reinforced concrete beams with epoxy-bonded FRP sheets were tested to failure using a symmetrical two point concentrated static loading system. The results show that the FRP strengthened beams exhibit increased strength, deformation capacity, ductility and composite action until failure. Keywords-FRP, Epoxy Resin, Flexure, Two Point Static Loading System
Strengthening of reinforced concrete beams in flexural using FRP
Concrete design, 2021
This research is a summary of previous researchers work done in this area.Excessive fatigue deterioration is usually experienced when Reinforced Concrete structural elements are subjected to loadings. This emphasizes the desire to strengthen as well as improve the fatigue performance and extend the fatigue life of RC structural components particularly beams. During the last few decades, strengthening of concrete structural elements by fibre-reinforced polymer (FRP) has become a widely used technique where high strength is needed for carrying heavy loads or repairing is done due to fatigue cracking, failure modes and or corrosion. This paper reviews various aspects of RC beams strengthened with FRP. This topic has not been covered comprehensively in previous studies, whereas the technology has been modified rapidly in the recent past. It highlights aspects such as surface preparation, adhesive curing, finite element(FE) simulation, fatigue performance as well as the failure modes of RC beams retrofitted with FRP. This technique eliminates and or reduces the crack growth rate, delay initial cracking, decline the stiffness decay with residual deflection and extend the fatigue life of RC beams. The best strengthening option in this case is pre-stressed carbon fibre-reinforced polymer (CFRP)
In this paper presents an experimental study conducted to examine the effectiveness of Fibre Reinforced Polymer (FRP) composites in enhancing the flexural capacity of concrete beams. In this study, Fibrereinforced polymer (FRP) application is a very effective way to repair and strengthen structures that have become structurally weak over their lifespan. Externally reinforced concrete beams with epoxy-bonded FRP sheets were tested to failure using a symmetrical two point concentrated static loading system. The results show that the FRP strengthened beams exhibit increased strength, deformation capacity, ductility and composite action until failure.
Analytical Study on RC Beams Strengthened for Flexure with Externally Bonded FRP Reinforcement
Composites Part B: …, 2011
This paper presents analytical study on reinforced concrete (RC) beams strengthened for flexure with externally bonded fiber reinforced polymer (FRP) reinforcement. A simple yet rational numerical model is developed and proposed for this purpose. The model is based on cross-sectional analysis satisfying strain compatibility and equilibrium conditions. The moment-curvature relationship can be generated for an RC beam section using an incremental strain technique. The model can also generate the loaddeflection relationship of the beam with respect to its configuration, loading system, and preloading conditions. The model can predict the flexural capacity of FRP-strengthened section based on full composite action and IC debonding failure modes. This also allows for designing the FRP strengthening area according to the desired failure mode. Various IC debonding criteria were adopted in the model and compared with test results from the literature. The result of comparison indicated that the accuracy of the model is dependent on the adopted IC debonding criterion. Furthermore, the model was verified against test data related to full composite action failure mode and good agreement was found.
Buildings
The design guidelines available in building codes for steel- and fibre-reinforced polymer (FRP) reinforced concrete (RC) beams have been developed on the basis of empirical models. While these models are successfully used for practical purposes, they require continuous improvements with more experimental data. This paper aims to develop a general mathematical model derived from the intrinsic material properties of concrete and certain reinforcements to analyse the bending behaviour of reinforced concrete beams. The proposed model takes into account the effects of non-linearity and ductility on the real behaviour of concrete under compression as well as the concrete tension stiffening. The model focused on analysing the flexural behaviour of rectangular steel, FRP and hybrid FRP–steel RC beams, using the moment–curvature relationship. A general static equilibrium equation was developed and mathematically solved with precise methods to establish a moment–curvature relationship. The ef...
Study on Flexural Behaviour of RC Beam Strengthened with FRP
Journal of Physics: Conference Series, 2021
This paper provides the analytical and experimental work of reinforced concrete beams strengthened with FRP. The main objective of this investigation is to study the flexural behaviour of reinforced concrete beams of different methods of strengthening methods using GFRP to find the flexural strength, failure modes, and ductility of the reinforced concrete beam. All beams were strengthened for flexure with external bonding to prevent flexural failure. The analytical and experimental results indicated that the externally bonded GFRP used for flexural strengthening of reinforced concrete beams increased the cracking load, increased the ultimate load-carrying capacity, and exhibited decreased ductility corresponding to the unstrengthen control specimen. The analytical work was carried out using ANSYS 17.0 Software and found the parameters of total deformation, stress strain curves, and Load deflection graph plotted.
Flexural strengthening of concrete beams using CFRP, GFRP and hybrid FRP sheets
Construction and Building Materials, 2012
h i g h l i g h t s " This paper highlights the efficiency of external strengthening for RC beams using FRP fabric. " Use of separate unidirectional glass and carbon fibres with some U-anchorages were tested. " Efficiency of bidirectional glass-carbon fibre hybrid fabric was also conducted. " Analytical model predictions compared well with measured FRP reinforced beam response. " The results reveal the cost-effectiveness of twin layer glass-carbon FRP fabric.
Turkish Journal of Civil Engineering
The effects of hooked end steel and polypropylene (PP) fibers on the behavior of large-scale doubly reinforced concrete beams under flexure were investigated using experimental and numeric methods. For this purpose, a total of eight beam specimens consisting in two groups were produced in the laboratory and three-point bending tests were conducted under monotonically increasing load. The beams in the groups were designed to have 0.86 and 1.30% tensile reinforcement ratios leading to either flexural or shear critical sections. Three out of eight were produced to be control samples and did not have any fiber additive while remaining five had 0, 0.5 and 1.0% steel or PP fibers by volume. Experimental results showed that the existence of 0.5% either type of fiber in densely reinforced specimens contributed to shear strength and allowed flexural capacities to be fully used instead of an improvement in the capacity. However, when the steel fiber ratio increased to 1.0% flexural capacity w...