Estimation of the Characteristic Value of Wood Strength

Christofóro, André Luis; Almeida, Andréa de Souza; Lanini, Tamiris Luiza Soares; Nogueira, Rodrigo de Souza; Lahr, Francisco Antônio Rocco

doi:10.1590/1809-4430-eng.agric.v39n1p127-132/2019

Cited by 8 publications

(6 citation statements)

References 12 publications

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“…Regarding f v0,k , Matos and Molina (2016) obtained, through tests for Eucalyptus saligna species, a λ equal to 0.13, whose value is close to the specifications of the ABNT NBR 7190-1 (2022). On the other hand, Christoforo et al (2019) obtained a λ equal to 0.23 for a grouping of five hardwood species. This result is according to the experiment of Couto et al (2020), which verified a λ equal to 0.22 for a set of 10 hardwoods, being a value approximately 80% higher than stated in ABNT NBR 7190-1 (2022).…”

Section: Introductionmentioning

confidence: 95%

Characteristic Strengths in the Compression and in the Static Bending as Parameters to Estimate Characteristic Shear Strength for Timber Design

et al. 2023

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To simplify the characterization of wood species, the Brazilian standard document ABNT NBR 7190-1 (2022) establishes the determination of mechanical properties employing the characteristic strength in the compression parallel to grain (fc0,k). This mechanical property is estimated using the linear relation given by the following expression fv0,k = 0.12·fc0,k Brazilian and European standard documents support the estimation of fv0,k using relations among properties. However, the European guidelines in the EN 384 (2019) have used the conventional characteristic strength in the static bending test (fM,k). Thus, this study aimed to investigate the efficiency of the ratio fv0,k = 0.12·fc0,k for adopting 30 hardwoods. The variance analysis results demonstrate the divergence among the experimental outcomes and those values estimated using the relation cited. Therefore, regression models at two parameters were considered to obtain more accurate estimates of fv0,k by adopting fc0,k, and fM,k as independent variables. Regarding the results, the geometric (R² = 80.80%) and linear (R² = 74.19%) models were the most accurate for the estimates of fv0,k in terms of fc0,k, and fM,k, respectively. This fact evinces the good accuracy of the models under consideration, which may provide a more rigorous structural design compared to the correlation currently prescribed by the ABNT NBR 7190-1 (2022).

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Section: Introductionmentioning

confidence: 95%

Characteristic Strengths in the Compression and in the Static Bending as Parameters to Estimate Characteristic Shear Strength for Timber Design

et al. 2023

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“…8 and Eq. 9 -used in studies by Christoforo et al (2012), Icimoto et al (2015), Ferro et al (2015), Lahr et al (2017), Almeida et al (2018), andChristoforo et al (2019)) using Newton's method with quadratic approximation was applied for determination of the optimal coefficient (λ) for relations Ec0 = λ•Et0 and Ec0 = EM/λ:…”

Section:  mentioning

confidence: 99%

“…Recently, Christoforo et al (2019) studied relations between characteristic compression strength (fc0,k), characteristic tensile strength parallel to the grain (ft0,k), and characteristic shear strength (fv0,k). The coefficients (α) they obtained after testing five tropical wood species were 0.96 and 0.23 for relations fc0,k = α•ft0,k and fv0,k = α•fc0,k, respectively, which were 25% and 92% higher than the coefficients specified by ABNT NBR 7190 (1997).…”

Section: Introductionmentioning

confidence: 99%

Analysis of relations between the moduli of elasticity in compression, tension, and static bending of hardwoods

Almeida

Aquino

Wolenski

et al. 2020

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Accurate estimation of average modulus of elasticity in compression parallel to the grain (Ec0) is of paramount importance for rational sizing of timber structures, given the use of this property in the estimation of stability of compressed parts (ultimate limit state, ULS) and in calculation of excessive strains (serviceability limit state, SLS). In Brazil, if values cannot be experimentally determined, ABNT NBR 7190 (1997) allows for estimation of Ec0 through relations to average modulus of elasticity both in tension parallel to the grain (Et0) (Ec0 = Et0) and in bending (EM) (Ec0 = EM/0.90). This research aimed to access the efficiency of these relations by testing 30 tropical wood species. The analysis of variance results showed that Ec0 and Et0 were statistically equal. However, Ec0 and EM/0.90 were not statistically equal, and the method of least squares resulted in a coefficient of 0.98, which was 8.89% higher than the one suggested by ABNT NBR 7190 (1997) and close to 1, thus, validating the results of ANOVA, which pointed on the equivalence between Ec0 and EM (Ec0 = EM). As an alternative to simplified equations of the standard, two-parameter regression models were used. The geometric model with R² = 91.67% proved to be the model of best fit, which demonstrated that Ec0 could be calculated as a function of EM.

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“…Aiming to ensure that the design of timber structures in the country follows the current state of knowledge, the ABNT NBR 7190 (1997) was canceled and replaced by this new version. ABNT NBR 7190 (1997) is discussed in numerous works that seek to contribute to this scientific progress (Lima, Jr et al 2018;Christoforo et al 2019;Almeida et al 2020;Christoforo et al 2020;Molina et al 2020;Lahr et al 2021;Soares et al 2021). It is noteworthy that there are already works in which the ABNT NBR 7190-1 (2022) code is used in the design (Fraga et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Comparative dimensioning of plane timber truss by ABNT NBR 7190:1997 method and ABNT NBR 7190-1:2022 method

Menezes

Fraga

Mascarenhas

et al. 2022

BioRes

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Wood, a renewable source and a material with excellent mechanical properties, is one of the oldest materials used in civil construction. In Brazil, its use is widespread in roof structures in the form of plane trusses. Given the Brazilian context of the growing presence of wood in structural systems, in addition to the normative updating processes, this study presents a comparison between calculation methods and possible increases in material consumption of wood for roof structure. The design methods compared are according to the recently published standard ABNT NBR 7190-1 (2022) and its previous version ABNT NBR 7190 (1997). The results were obtained via iTruss software, which includes linear-elastic structural analysis by the finite element method (FEM). It was concluded that the ABNT NBR 7190-1 (2022) presents a conservative dimensioning in relation to the previous version of 1997, favoring safety. However, there were no significant increases in wood consumption, demonstrating the efficiency of the revised version.

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Estimation of the Characteristic Value of Wood Strength

Cited by 8 publications

References 12 publications

Characteristic Strengths in the Compression and in the Static Bending as Parameters to Estimate Characteristic Shear Strength for Timber Design

Characteristic Strengths in the Compression and in the Static Bending as Parameters to Estimate Characteristic Shear Strength for Timber Design

Analysis of relations between the moduli of elasticity in compression, tension, and static bending of hardwoods

Comparative dimensioning of plane timber truss by ABNT NBR 7190:1997 method and ABNT NBR 7190-1:2022 method

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