Shrinkage for Some Wood Species Estimated by Density

Christofóro, André Luis; Almeida, Tiago Hendrigo de; Almeida, Diego Henrique de; Santos, Júlio César dos; Panzera, Túlio Hallak; Lahr, Francisco Antônio Rocco

doi:10.5923/j.ijme.20160602.01

Cited by 23 publications

(20 citation statements)

References 9 publications

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“…The required lumber production to meet demand makes this sector one of the leading employers and drives the economy in Brazil (Fiorelli and Dias 2003;Almeida et al 2015;Christoforo et al 2015). Wood is used either directly in the structure of the building or as a component of other subsystems (De Araujo et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Density as Estimator of Dimensional Stability Quantities of Brazilian Tropical Woods

Almeida¹,

Almeida²,

Araújo³

et al. 2017

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Wood is a material widely used in various sectors of construction, such as in structures and building components. The volume of wood extracted from tropical forests has reached a considerable amount, and this wood is marketed with popular names without prior characterization. Wood density is an easy property to measure, and its use as an estimator of other properties is very common in this sector. This study investigated the possibility of the estimation of important quantities in dimensional stability of Brazilian tropical woods by using the density at 12% moisture content, anhydrous density, and basic density. Testing the ability to estimate radial, axial, tangential, and volumetric shrinkage, anisotropy coefficient, coefficient of volumetric rate of volumetric shrinkage, as well as the rate of volumetric swelling using the densities above, with linear, exponential, geometric, and logarithmic models, the best determination coefficient was: R 2 = 19.58%. The results were, in summary, that the variable density was not a good estimator of the dimensional stability of the wood.

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Section: Introductionmentioning

confidence: 99%

Density as Estimator of Dimensional Stability Quantities of Brazilian Tropical Woods

Almeida¹,

Almeida²,

Araújo³

et al. 2017

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“…Results showed only correlation when considered species as a group. Christoforo et al [14] evaluated the possibility to estimate: (a) shrinkage in the three preferential directions in wood; (b) anisotropy coefficient; (c) coefficient of shrinkage, in the cited directions, for five species of hardwoods, relying on strength classes proposed by NBR 7190:1997. The best results showed adjusted coefficient of determination only 54%.…”

Section: Introductionmentioning

confidence: 99%

“…However, knowledge of the physical properties, specifically those involving dimensional stability of wood, i.e. shrinkage [radial (R); tangential (T), longitudinal (L), volumetric (V)] and coefficient of anisotropy (CA) are fundamental for a well-developed design and, so, a better use of the material [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Density as Estimator of Shrinkage for Some Brazilian Wood Species

Cavalheiro¹,

Almeida²,

Almeida³

et al. 2016

ijme

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Shrinkage and coefficient of anisotropy are fundamental physical parameters in analysis of dimensional stability of timber structures members. In Brazil, properties of wood are obtained according to assumptions and calculation required by Annex B of ABNT NBR 7190: 1997 (Timber Structures Design). Among the physical properties, density appears as the easiest one to be experimentally obtained, defined by ratio between mass of the sample and its volume. To evaluate the possibility of estimating shrinkage (longitudinal, RL; radial, RR; tangential, RT; volumetric, RV; and coefficient of anisotropy, CA) of wood depending on density, this study aimed to test regression models (linear, exponential, logarithmic, geometric) using basic density (ρ bas ) and apparent density (ρ 12 ) as independent variables. For this purpose, five wood species belonging to conifers: Pinus sp., Pinus oocarpa; and dicotyledonous: Paricá (Schizolobium amazonicum), Jatobá (Hymenaea sp.) and Lyptus®, were employed. In all, 23 samples for Pinus sp.; 15 for Pinus oocarpa; 28 for Paricá; 16 for Lyptus®; and 11 for Jatobá were produced, totaling 651 determinations. Results of analysis of variance for regression models indicated insignificance of the adjustments obtained by adopting densities as estimators of shrinkage and coefficient of anisotropy for this set of wood species. Only models involving basic density and apparent density were significant, wherein the optimal settings were from linear case, exhibiting coefficient of determination (R 2 ) 91.72% (for softwoods) and 83.36% (for hardwoods).

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“…The wood is a material of natural and renewable source, and has good relation between strength and density [1][2][3][4][5][6][7][8]. The natural round wood is an excellent solution because it does not require wood processing [8][9][10][11][12][13][14], commonly used in structural projects, such as bridges, in which concrete can also be used in conjunction with wood [15], consisting of steel bars and resins as the joining elements between wood and concrete materials.…”

Section: Introductionmentioning

confidence: 99%

Pull out Strength Evaluation of Steel Bars Bonded-in to 45° in Round Timbers of Corymbia citriodora Treated with CCA

Pigozzo¹,

Arroyo²,

Christofóro³

et al. 2017

ijme

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With the possibility of developing simple connections, of easy execution, strong and durable, the bonded-in steel bars with structural resins have started being applied to different situations, such as shear connectors in mixed wood-concrete structures. These connectors, when steel bars are inclined in relation to the grain, may work under axial forces transmitting more stiffness and strength to the connection. In this research, the pull out strength of bonded-in steel bars was evaluated, bent 45° in relation to wood grain, using epoxy resin Sikadur-32 Fluid. In random sample of round pieces of Eucalyptus citriodora (Corymbia citriodora), CCA treated, with six replications in each observation, and considering the variability of the parameters: natural wood mechanical properties; apparent density; bar diameters; adherence surface and the moisture content. Steel bars used were highly resistant ones (CA-50), with threaded surface solicited by axial force, under monotonic loadings, with two consecutive load cycles. From the analysis of variance (ANOVA), the increase in the moisture content promoted reductions in the values of the compressive strength. The estimate of the pullout strength by the multivariable regression model, the moisture content was considered not significant, increases in the area of anchoring strengths implied significant increases in anchorage strength values, and the interaction between the factors (anchoring area and moisture content) promoted reductions in the anchor strength values of the steel bars.

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Shrinkage for Some Wood Species Estimated by Density

Cited by 23 publications

References 9 publications

Density as Estimator of Dimensional Stability Quantities of Brazilian Tropical Woods

Density as Estimator of Dimensional Stability Quantities of Brazilian Tropical Woods

Density as Estimator of Shrinkage for Some Brazilian Wood Species

Pull out Strength Evaluation of Steel Bars Bonded-in to 45° in Round Timbers of Corymbia citriodora Treated with CCA

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