Modulus of elasticity of I-214 young poplar wood from standing trees to sawn timber: influence of the age and stand density

Gallego, Antolino; Ripoll, M.A.; Timbolmas, Cristian; Rescalvo, Francisco J.; Suárez, Elisabet; Valverde, I.; Rodríguez, María Fernández; Reyes, Francisco Bruno Navarro; Merlo, Edgard Monforte

doi:10.1007/s00107-021-01675-5

Cited by 8 publications

(14 citation statements)

References 42 publications

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“…Poplar is a fast-growing species with a rotation of 9 years in the south of Spain and up to 18 years in the north, which in 2016 covered an extension of 145.000 ha approximately [13]. The use of poplar for construction supports what the Food and Agriculture Organization of the United Nations requires for 2050, when it is expected that the 75% of the wood used for industrial purposes will come from fast-growing plantations [14].…”

Section: Introductionmentioning

confidence: 94%

“…Characteristic values of the structural properties of the 18 year-old Populus x euroamericana, hybrid I-214, from the North of Spain were 36.3 N/mm 2 for bending strength ( f m,k ), 7746 N/mm 2 for the mean modulus of elasticity (E 0,m ), and 338 kg/m 3 for density (ρ k ) [15]. The values of modulus of elasticity increased to 8800 N/mm 2 for the same hybrid from Central Spain (Guadalajara) [13] and to 9907 N/mm 2 for Portuguese poplar (Populus alba and Populus nigra) [16], showing in all the cases structural properties similar to softwood species. Until 2003, poplar was included in UNE 56544, but due to the lack of updating data of new species and hybrids it was removed.…”

Section: Introductionmentioning

confidence: 96%

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Embedment Strength of Low- and Medium-Density Hardwood Species from Spain

Cabrera

Moltini

Baño³

2022

Forests

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The embedment strength is a key parameter in the design of timber connections with metal fasteners. This property can be determined by the equations given by design codes such as the Eurocode 5, which are based on the European Yield Model proposed by Johansen, and it depends on the value of timber density among other parameters. These equations provided by design codes are based on experimental tests performed mainly in softwood species; thus, the objective of this work is to evaluate the embedment strength of two low- and medium-density hardwood species from Spain (poplar—Populus x euroamericana; beech—Fagus sylvatica) in the parallel and perpendicular to grain directions. Four different experimental test configurations were carried out according to EN 383 for each species using two different fasteners: (i) a 9 mm-diameter screw and (ii) a 12 mm-diameter bolt. Results of embedment strength were evaluated according to three different determination methods, and later compared with the current equations provided by Eurocode 5 (EC5) and new ones proposed in the draft of the new Eurocode 5 (prEC5). Results showed that current equations overestimated perpendicular to grain embedment strength for the cases studied, while the equation proposed in prEC5 for screws fitted best perpendicular to grain embedment strength. However, it underestimated the parallel to grain one because it does not consider any difference due to load-to-grain angle (α). Finally, ratios between experimental parallel and perpendicular to grain embedment strength were studied (k90), showing 30% and 44% higher values than the theoretical values resulting from k90 equations of EC5 and prEC5 for beech with screws and bolts, respectively, and 4% and 49% higher than the theoretical values for poplar with screws and bolts, respectively.

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Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 96%

Embedment Strength of Low- and Medium-Density Hardwood Species from Spain

Cabrera

Moltini

Baño³

2022

Forests

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“…Characteristic values of the structural properties of the 18-year-old Populus x euroamericana, hybrid I-214, from the North of Spain were N/mm 2 , N/mm 2 , and kg/m 3 [20], which fit with the strength class C14 of EN 338:2016 [21]. The values of modulus of elasticity increased to 8800 N/mm 2 for the same hybrid from Central Spain (Guadalajara) [19] and to 9907 N/mm 2 for Portuguese poplar (Populus alba and Populus nigra) [22], showing in all the cases structural properties like softwood species. Until 2003, poplar was included in the Spanish timber grading standard [16], but it was removed due to the lack of updated data on new species and hybrids.…”

Section: Introduction 45mentioning

confidence: 98%

“…The increasing demand for wood is leading the industry to look for alternative species for structural uses, both fast-growing with lower mechanical properties, such as poplar, and slow-growing with higher mechanical properties, such as beech. The rotation of poplar varies between 9 years in the south of Spain and up to 18 years in the north, depending not only on the origin but also on the subspecies and hybrid, and in 2016 the cuts represented 1.6% of the total cuts and 3.1% of hardwoods in Spain [19]. Characteristic values of the structural properties of the 18-year-old Populus x euroamericana, hybrid I-214, from the North of Spain were N/mm 2 , N/mm 2 , and kg/m 3 [20], which fit with the strength class C14 of EN 338:2016 [21].…”

Section: Introduction 45mentioning

confidence: 99%

Influence of Density and Predrill in the Embedment Strength of Two Hardwood Species

Cabrera

Moltini

Baño

2023

World Conference on Timber Engineering (WCTE 2023)

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The embedment strength is a key parameter in the design of timber connections with metal fasteners. It can be determined by the equations given by Eurocode 5 from the density value. Since those equations were mainly developed for softwood species, the objective of this work is to evaluate the influence of the density in the embedment strength of two high-and low-density hardwood species (beech -Fagus sylvatica-and poplar -Populus x euroamericana-, respectively) in the parallel-and perpendicular-to-grain direction. Four different experimental test configurations were carried out according to EN 383 for each species using a 5-mm nominal diameter and considering the influence of predrilling in the wood specimens. Results showed a good correlation between density and embedment strength for all the test types. In addition, predrilling showed no significant influence on the value of embedment strength, contrary to what is considered in the equations provided by the current version of the structural design codes. Both, current and new equations proposed by the new draft of Eurocode underestimate the values of embedment strength in both species, thus being on the safe side for the structural design of connections.

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“…At present, scholars at home and abroad have mainly conducted research on the relevant mechanical properties of tree branches such as jujube, litchi, longan, willow, etc. The results suggest that the physical and mechanical properties of branches are the basis for developing the relevant processing machinery (Monteiro et al 2020) (El Haouzali et al 2020) (Gallego et al 2021). For instance, Wang et al measured the tensile and shear mechanical properties of jujube branches by using the finite element method, predicted the macroscopic mechanical parameters of jujube branches, and evaluated the accuracy of the finite element simulation results through experiments (Wang et al 2020).…”

Section: Introductionmentioning

confidence: 99%

Test and analysis of mechanical properties of poplar branches

Zhao,

Zhou,

Jing

et al. 2023

Preprint

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The mechanical properties of poplar branches are the basis for designing and optimizing the working parameters of branch pruning and crushing machinery. In this paper, a precision microcomputer-controlled electronic universal testing machine was used to test the tensile, compression, bending, and shear mechanical properties of poplar branches. The test results suggested that the elastic constitutive relationship of the stress-strain curves of poplar branches under longitudinal compression, transverse compression, and bending conformed to Hooke's law, and longitudinal tensile and shear exhibited plastic damage; the anti-failure strength, anti-failure elastic modulus and external work of poplar branches under longitudinal compression were greater than those under transverse compression. Meanwhile, the analysis results indicated that there was an exponential function positive correlation between longitudinal tensile strength and longitudinal tensile work, a polynomial exponential function positive correlation between longitudinal compressive strength and longitudinal compressive work, a power function positive correlation between transverse compressive proportional ultimate strength and transverse compressive work, and an exponential function positive correlation between bending strength and bending work; meanwhile, there was a polynomial function positive correlation between the peak shear force and the cross-sectional area of the sample, and there was an exponential function positive correlation between the shear work and the cross-sectional area of the sample. Additionally, the external work required to destroy poplar branches can be estimated using the established regression equation. The study results of this paper provide important data support for poplar branch pruning and crushing simulation tests and machine power selection.

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Modulus of elasticity of I-214 young poplar wood from standing trees to sawn timber: influence of the age and stand density

Cited by 8 publications

References 42 publications

Embedment Strength of Low- and Medium-Density Hardwood Species from Spain

Embedment Strength of Low- and Medium-Density Hardwood Species from Spain

Influence of Density and Predrill in the Embedment Strength of Two Hardwood Species

Test and analysis of mechanical properties of poplar branches

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