Determination of the influence of size and position of knots on load capacity and stress distribution in timber beams of Pinus sylvestris using finite element model

Baño, Vanesa; Martitegui, Francisco Arriaga; Fernández, Manuel Guaita

doi:10.1016/j.biosystemseng.2012.12.010

Cited by 29 publications

(17 citation statements)

References 7 publications

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“…First, it is seen that the visual classification by itself is not a reliable way to estimate the bending stress capacity of the element. This is basically due to the influence of the position of the knots, an aspect not considered by the visual classification method [ 33 ]. For example, one beam classified as rejected, NR-2, had a 29% higher corrected MOR than a beam classified as MEG, beam NR-3.…”

Section: Resultsmentioning

confidence: 99%

Experimental Comparison of Different Carbon Fiber Composites in Reinforcement Layouts for Wooden Beams of Historical Buildings

et al. 2017

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This paper offers a detailed, quantitative and exhaustive experimental comparison in terms of mechanical properties of three different layouts of carbon composite materials (CFRP) used to strengthen existing old timber beams highly affected by diverse natural defects and biological attacks, testing the use of pultruded laminate attached on the tension side of the element (LR), CFRP fabrics totally U-shape wrapping the timber element (UR), and the combined use of both reinforcement solutions (UR-P). Moreover, unidirectional and bidirectional fabrics were considered and compared. Timber elements used for the experimental program were extracted from a recent rehabilitation of the roof of the current Faculty of Law building, University of Granada (Spain), catalogued as a historical edifice. Experimental results from bending tests show that in all cases reinforcement provides a clear improvement in terms of bending capacity and stiffness as compared with the control specimens (without reinforcement). However, improvements in terms of ductility differ considerably depending on the kind of layout.

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Section: Resultsmentioning

confidence: 99%

Experimental Comparison of Different Carbon Fiber Composites in Reinforcement Layouts for Wooden Beams of Historical Buildings

et al. 2017

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“…The most relevant singularities considered in visual strength grading for structural sawn timber are knots and grain deviation (14). According to vande-Kuilen and Blass (15) the main features of visual grading standards are based on the most common causes of failure; grain deviation in tropical hardwoods and knots in the case of softwoods, because bending strength decreased with increasing knot size (16). According to Ridley-Ellis et al (17), visual grading does not accurately grade timber directly into strength classes (C14, C16, C18, C20, …), because the latter are so close to each other.…”

Section: Introductionmentioning

confidence: 99%

Comparison between wet and dry timber visual strength grading according to the Spanish (UNE 56544) and German (DIN 4074-1) standards

et al. 2019

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Visual strength grading is widely used to estimate mechanical properties of structural timber. National visual grades are allocated to strength classes according to European standard EN1912. The recent discussion about the proper function of visual strength grading standards and the assignment of strength classes shows the need for further research in this field. Spanish-sourced radiata, Scots, Salzmann and maritime pine timber samples were visually graded in wet and dry condition according to the Spanish UNE56544 (2011) and German DIN4074-1 (2012) standards. Rejection was far higher dry due to distortion (warping) parameters. However, this rejection could be significantly mitigated by adopting a higher twist limit (2 mm / 25 mm width). UNE 56544 is more suitable for visually grading these species because it was specifically designed for them and a Spanish source. However, both standards underestimated the Scots pine rejection pieces which mechanical properties fulfill the MEG and S10 grades.

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“…Some examples of potential uses of these species are residential construction, light framing systems, prefabricated load bearing floors and walls in multistory buildings, and long span glulam beams in buildings and civil structures. The design and modeling of wooden products and structures involving numerical simulations requires the full characterization of the elastic and strength properties of the wood (He et al 2001;Baño et al 2013;Nadir et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Elastic Behavior of Fast-Growth Uruguayan Pine Determined from Compression and Bending Tests

Moya

Baño

2017

BioResources

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The design of engineered wood products and timber structures involving numerical simulations requires knowledge of the elastic and strength properties of wood. This study characterized the elastic behavior of Uruguayan pine wood (Pinus elliottii and P. taeda). A series of compression tests with the load applied with respect to various grain directions and bending tests were performed on small and clear specimens to determine the elastic constants and establish the relationships between the longitudinal moduli of elasticity obtained by the two testing methods. Moduli of elasticity, shear moduli, and Poisson ratios were determined. The longitudinal stiffness values in compression from the same specimen obtained by the two testing methods were similar. The moduli of elasticity in tension and compression parallel to the grain for the elastic behavior was obtained from experimental bending tests, and the downshift of the neutral axis until rupture was found. Using a model that simulates the post-elastic behavior as a curve comprised of several straight lines, the stress-strain diagram for tension and compression parallel to the grain was obtained.

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Determination of the influence of size and position of knots on load capacity and stress distribution in timber beams of Pinus sylvestris using finite element model

Cited by 29 publications

References 7 publications

Experimental Comparison of Different Carbon Fiber Composites in Reinforcement Layouts for Wooden Beams of Historical Buildings

Experimental Comparison of Different Carbon Fiber Composites in Reinforcement Layouts for Wooden Beams of Historical Buildings

Comparison between wet and dry timber visual strength grading according to the Spanish (UNE 56544) and German (DIN 4074-1) standards

Elastic Behavior of Fast-Growth Uruguayan Pine Determined from Compression and Bending Tests

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