On the role of CFRP reinforcement for wood beams stiffness

Ianăşi, Aurora Cătălina

doi:10.1088/1757-899x/95/1/012015

Cited by 8 publications

(8 citation statements)

References 2 publications

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“…The addition of carbon plates and sheets increases stiffness ranging from 20.2% to 29.6% [161]. In addition, an experimental study of reinforcing laminated wood beams using CFRP and GFRP composite sheets was conducted.…”

Section: Effect Of the Cfrp On Flexural Stiffness Enhancement Of Timbermentioning

confidence: 99%

Strengthening Timber Structural Members with CFRP and GFRP: A State-of-the-Art Review

Saad

Lengyel

2022

Polymers

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The application of fibre-reinforced polymers (FRP) for strengthening timber structures has proven its efficiency in enhancing load-bearing capacity and, in some cases, the stiffness of structural elements, thus providing cost-effective and competitive alternatives both in new design and retrofitting existing historical buildings. Over the last few decades, several reinforcing materials and techniques evolved, and considerable progress was made in numerical modelling, especially using the finite element method. As this field of research has become extensive and diversified, as well as numerous contradicting results have emerged, a thorough review is necessary. This manuscript covers the topics of historical preliminaries, reinforcing with carbon and glass fibre composites, bond characteristics, main reinforcing techniques, modelling of knots, and the effects of the fibre waviness on the composite behaviour. A detailed overview is given on the experimental and numerical investigation of mechanics of strengthened beams. A one-of-a-kind table that compares the stiffness improvement observed in several studies with analytical estimates. Attention is drawn to a number of challenges that have arisen, e.g., the moderate stiffness enhancement, composite-to-wood interface, modelling of knots, and strengthening of defected timber members. This paper can be used as a starting point for future research and engineering projects.

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Section: Effect Of the Cfrp On Flexural Stiffness Enhancement Of Timbermentioning

confidence: 99%

Strengthening Timber Structural Members with CFRP and GFRP: A State-of-the-Art Review

Saad

Lengyel

2022

Polymers

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“…Moreover, the use of CFRP sheets for wood strengthening resulted in a stiffness increase of 15–60% [ 23 ], and an increase of 20% in another study [ 24 ]. The introduction of carbon plates and sheets leads to a stiffness increase varying from 20.2% to 29.6% [ 25 ].…”

Section: Introductionmentioning

confidence: 99%

Experimental, Analytical, and Numerical Assessments for the Controversial Elastic Stiffness Enhancement of CFRP-Strengthened Timber Beams

Saad

Lengyel

2022

Polymers

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The strengthening of timber beams with carbon-fibre-reinforced polymers (CFRP) has been widely used in the last decades to enhance the behaviour of historical or new timber structures, usually for bending. While considerable improvement in capacity and ductility is typically achieved, the increase in stiffness was, in many cases, well short of analytical expectations, which tend to overestimate stiffness. This study addresses the problem by investigating the underlying mechanical behaviour using experimental, analytical, and numerical tools on a sample of Norway spruce (Picea abies) beams reinforced with carbon-fibre fabric. In the experimental program, each beam is tested for bending with and without CFRP reinforcement in order to determine specimen-specific stiffness increase on an individual basis. The reinforcement yielded an increase of 27% in capacity, 53% in ultimate displacement, and 133% in compliance, verifying its efficiency. Axial compression tests on an independent sample are also performed to verify modulus of elasticity in compression. Numerical computations based on a beam model and a three-dimensional finite element model are performed with the introduction of separate moduli of elasticity for tension and compression in timber. Inverse computation using the experimental load–deflection curves yielded the moduli and the compression yield stress of timber to provide the best match between tests and simulations. The mean difference of only 6% in stiffness between FEM and the tests is obtained. The dominance of normal stresses in the longitudinal direction is found, in correspondence with the experimentally observed tensile failure of timber (apart from a few defected specimens). Compression yield stresses are within 7% (beam model) and 2% (FEM) error compared with the control axial tests. The differences between FE simulations and tests in ultimate load and compliance are within 1%. This study concludes that the application of CFRP in the composite beams enables the determination of timber material properties opposed to pure timber beams without reinforcement, and the adoption of separate moduli of elasticity for tension and compression leads to adequate modelling of reinforced timber beams.

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“…Reinforcements with epoxy and FRP, with glass, carbon and basalt fibres, in their different forms, have been applied with the aim of increasing performance and improving the strength and stiffness of structural elements (FIORELLI;DIAS, 2003;BALSEIRO, 2007;NEUBAUEROVÁ, 2012;ROSA;ESCAMILLA;GARCÍA, 2013;BERTOLINI et al, 2014;IANASI, 2015). According to Balseiro (2007), the timber reinforcement with glued fibre laminates has, as the most common failure mode, the delamination, either in the bond line or in the adjacent area.…”

Section: Introductionmentioning

confidence: 99%

Influence of temperature on the adhesion of fibre reinforced polymers to timber surface

et al. 2019

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Carbon and glass fibre reinforced polymer composites are being increasingly used in timber structures, where they can be exposed to harsh temperature conditions. In order to be properly used, information is needed on their adhesion to the substrate. The objective of this research is to evaluate the influence of temperatures between 20 and 80 ºC on the adhesion of these reinforcements to the wood. The shear test of adhesive line and pull-off test of the reinforcement from wood surface were carried out using specimens made of Pinus spp. The results demonstrated that temperature causes the nonlinear reduction of the reinforcement adhesion. The specimens exposed to a temperature of 80 °C presented residual bond strength means of 34% and 20% of the mean strength at room temperature for CFRP and for GFRP, respectively. Caution in using the applied resins is required due to the presented behaviour even in the service temperature range specified by the manufacturers.

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On the role of CFRP reinforcement for wood beams stiffness

Cited by 8 publications

References 2 publications

Strengthening Timber Structural Members with CFRP and GFRP: A State-of-the-Art Review

Strengthening Timber Structural Members with CFRP and GFRP: A State-of-the-Art Review

Experimental, Analytical, and Numerical Assessments for the Controversial Elastic Stiffness Enhancement of CFRP-Strengthened Timber Beams

Influence of temperature on the adhesion of fibre reinforced polymers to timber surface

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