A method for flexural reinforcement of old wood beams with CFRP materials

Borri, Antonio; Corradi, Marco; Grazini, Andrea

doi:10.1016/j.compositesb.2004.04.013

Cited by 228 publications

(135 citation statements)

References 6 publications

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“…This natural and renewable material is characterized by high strengths under parallel to grain tension and compressive loads, which are nearly unique as specific properties (i.e., divided by its weight). Moreover, it performs well under the influence of wind and especially earthquake loads, due to the low stiffness of wood, especially in the direction perpendicular to fibres, providing a redistribution of loads in the structure [3][4][5][6][7]. However, without proper maintenance, wood deteriorates due to fungi and insects, and swelling and shrinkage caused by variations on ambient humidity.…”

Section: Introductionmentioning

confidence: 99%

“…Transversely to these issues, wood is tolerant to large strains before failure, necessary to develop the characteristic high strength of composite materials [9]. The study of wood structures reinforced with composites dates back to the 1980s and has been under research since then [5,[10][11][12][13][14][15]. The work of Borri et al [5] is a comprehensive experimental and numerical study on the reinforcement of wood beams with unidirectional CFRP laminates and pultruded bars.…”

Section: Introductionmentioning

confidence: 99%

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Experimental and numerical evaluation of composite repairs on wood beams damaged by cross-graining

Campilho

Moura

Barreto

et al. 2010

Construction and Building Materials

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Keywords:Wood Composite Repair Cohesive zone models Finite element analysis a b s t r a c t An experimental and Finite Element study was performed on the bending behaviour of wood beams of the Pinus Pinaster species repaired with adhesively-bonded carbon-epoxy patches, after sustaining damage by cross-grain failure. This damage is characterized by crack growth at a small angle to the beams longitudinal axis, due to misalignment between the wood fibres and the beam axis. Cross-grain failure can occur in large-scale in a wood member when trees that have grown spirally or with a pronounced taper are cut for lumber. Three patch lengths were tested. The simulations include the possibility of cohesive fracture of the adhesive layer, failure within the wood beam in two propagation planes and patch interlaminar failure, by the use of cohesive zone modelling. The respective cohesive properties were estimated either by an inverse method or from the literature. The comparison with the tests allowed the validation of the proposed methodology, opening a good perspective for the reduction of costs in the design stages of these repairs due to extensive experimentation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental and numerical evaluation of composite repairs on wood beams damaged by cross-graining

Campilho

Moura

Barreto

et al. 2010

Construction and Building Materials

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“…However, their durability is questionable due to some of their characteristics. Starting in the early 1960s, reinforcement with conventional techniques employing both fiber-reinforced plastics (FRP) and non-FRP materials has been studied [1,2] . The following review summarizes some of these studies.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of flexural performance of wood beams using textile fabrics

Beylergi̇l¹,

Aktaş²,

Pekbey³

2012

Science and Engineering of Composite Materials

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Abstract:The aim of this study was to investigate the flexural performance of wood beams (beech -Fagus orientalis Lipsky) reinforced with woven and selected weft knitted glass fabrics, namely, Milano and plain knit. Some physical and mechanical properties of the beech wood and the textile fabrics were determined in accordance with relevant ASTM standards. Twenty-four wood beams which have two different cross sections (I-shaped and square hollow) were manufactured and tested under a threepoint load. They were divided into two groups: Group A specimens were not reinforced to serve as a reference, whereas Group B specimens were reinforced with textile fabrics combined with adhesion. The flexural behavior of the specimens was studied through their load-deflection characteristics. The modes of failure were identified and categorized. The experimental results showed that the load-bearing capacity of reinforced beams increased significantly compared to the beam without reinforcement. This method can be used to repair and strengthen damaged wood beams.

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“…Even though these solutions were efficient, they highly increased the structure's weight. Nowadays, composite materials such as fiber reinforced polymers (FRP) come as a new option in order to improve structural capacity and stiffness of timber structures (Triantafillou 1998;Johns and Lacroix 2000;Lopez-Anido and Xu 2002;Radford et al 2002;Borri et al 2005;Buell and Saadatmanesh 2005;Yail and Kent 2010).…”

Section: Introductionmentioning

confidence: 99%

Static and dynamic properties of retrofitted timber beams using glass fiber reinforced polymers

et al. 2014

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Abstract:A study on the static and dynamic properties of sawn timber beams reinforced with glass fiber-reinforced polymer (GFRP) is reported in this paper. The experimental program is focused on the behavior of unidirectional wooden slabs, and the main objective is to fulfill the service state limit upon vibrations using GFRP when an architectonical retrofitting project is necessary. Two different typologies of reinforcement were evaluated on pine wood beams: one applied the composite only on the lower side of the beams, while the other also covered half of the beams depth. For the dynamic characterization, the natural frequency, damping ratio, and dynamic elastic modulus were measured using two different techniques: experimental modal analysis upon the whole beams; and bandwidth method using smaller samples of the same material. The static characterization consisted on four point bending tests, where elastic modulus, bending strength and ductility were assessed. The lower composite had better ductility and bending strength. On the other hand, the U-shaped laminate showed higher stiffness but also at a higher material cost. However, it allowed some ductility, i.e. compressive plasticity, even in the presence of hidden knots. Both dynamic techniques gave similar results and were capable of measuring the structure stiffness, even if short samples were used. Finally, the changes on dynamic properties because of the GFRP did not jeopardize the dynamic performance of the reinforced timber beams. fiber-reinforced polymer (GFRP) is reported in this paper. The experimental program is focused on the behavior of unidirectional wooden slabs, and the main objective is to fulfill the service state limit upon vibrations using GFRP when an architectonical retrofitting project is necessary. Two different typologies of reinforcement were evaluated on pine wood beams: one applied the composite only on the lower side of the beams, while the other also covered half of the beams depth. For the dynamic characterization, the natural frequency, damping ratio, and dynamic elastic modulus were measured using two different techniques: experimental modal analysis upon the whole beams; and bandwidth method using smaller samples of the same material. The static characterization consisted on four point bending tests, where elastic modulus, bending strength and ductility were assessed. The lower composite had better ductility and bending strength. On the other hand, the U-shaped laminate showed higher stiffness but also at a higher material cost. Powered by Editorial Manager® and ProduXion Manager® from Aries Systems CorporationHowever, it allowed some ductility, i.e. compressive plasticity, even in the presence of hidden knots. Both dynamic techniques gave similar results and were capable of measuring the structure stiffness, even if short samples were used. Finally, the changes on dynamic properties because of the GFRP did not jeopardize the dynamic performance of the reinforced timber beams.

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A method for flexural reinforcement of old wood beams with CFRP materials

Cited by 228 publications

References 6 publications

Experimental and numerical evaluation of composite repairs on wood beams damaged by cross-graining

Experimental and numerical evaluation of composite repairs on wood beams damaged by cross-graining

Enhancement of flexural performance of wood beams using textile fabrics

Static and dynamic properties of retrofitted timber beams using glass fiber reinforced polymers

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