Improving density estimation in large cross-section timber from existing structures optimizing the number of non-destructive measurements

Osuna-Sequera, Carlos; Llana, Daniel F.; Esteban, Miguel; Martitegui, Francisco Arriaga

doi:10.1016/j.conbuildmat.2019.03.144

Cited by 18 publications

(7 citation statements)

References 17 publications

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“…Bobadilla et al [29] proposed a measure per meter, and if possible, in different faces. For structural timber members, Osuna-Sequera et al [54] recommended to carry out a minimum number of three or four measurements using Wood Extractor, commencing readings in the central one-third of the piece (the area of the maximum bending moment)…”

Section: Resultsmentioning

confidence: 99%

Wood Density Determination by Drilling Chips Extraction in Ten Softwood and Hardwood Species

Martínez¹,

Balmori²,

Llana

et al. 2020

Forests

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Research Highlights: The novelty of this study is the development of an accurate wood density estimation method based on a relatively brand new semi-destructive testing technique (drilling chips extraction). This method is especially crucial in the assessment of existing timber structures. Background and Objectives: Probing, drilling, and coring are non-destructive and semi-destructive techniques commonly used for timber density estimation in existing timber structures. Most of these techniques show poor or medium accuracy or are so expensive or destructive. This paper aims to obtain accurate estimation models for wood density in existing structures using the easy to use drilling chips extraction technique. Materials and Methods: 300 specimens (95 × 65 × 200 mm3) from ten softwood and hardwood species covering a wide range of density (from 350 to 980 kg·m−3) were tested after conditioning. The Wood Extractor device based on the drilling chips extraction technique was used in the radial and the tangential direction. Mass of the chips collected (drilling residue) from each drill was recorded. Results: Density obtained from drilling residue was not statistically significantly different between radial and tangential directions avoiding take into account direction when measuring. The density obtained in the whole specimens is slightly higher than the density obtained by drilling residue being this difference uniformly through the range of densities studied. Two different estimation models were presented with high determination coefficients (96% and 97%) and low standard errors. These results were similar to those obtained by other authors using core drilling but causing less damage. Conclusions: Drilling chips extractor is a simple, reliable and inexpensive method to estimate density in existing structures with accuracy.

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Section: Resultsmentioning

confidence: 99%

Wood Density Determination by Drilling Chips Extraction in Ten Softwood and Hardwood Species

Martínez¹,

Balmori²,

Llana

et al. 2020

Forests

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“…This value is higher than the one obtained with the Pylodin, but lower than those related to the other three test methodologies. Similarly, Osuna-Sequera et al 2019 [11] compared the NPR, SWR and DCE methods in order to optimize the number of measurements to be performed along extended wooden elements where the density variation, due to the growth of the original tree, becomes important from one end to the other. Then, they demonstrate that the penetration depth measured with the WP is considerably influenced by the position of the test area reaching differences up to 5 mm between the bottom of the original tree and a section 10 meters high.…”

Section: Woodpeckermentioning

confidence: 99%

Sustainable Assessment: A Contribution to Improve the Reliability of NDT on Old Chestnut Purlins

Borghese

Santini

Sguerri

2023

World Conference on Timber Engineering (WCTE 2023)

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The aim of this study is to give an additional contribution to the improvement of a sustainable diagnostic practice to be used for the assessment of ancient wooden structures, in order to limit the damage of the existing ones through destructive tests, and to have a reliable prediction of old element properties, with their historical value, reducing demolition and substitution with consumption of new materials. To achieve this purpose, correlation laws and methodologies that can be used to facilitate the performance of non-destructive testing (NDT) in situ, will be highlighted. Seventeen chestnut purlins, dated between the 19th century and the 20th century and coming from the roof of the Cloister of Michelangelo at the Baths of Diocletian in Rome, are tested. As the first part of a wider experimentation, the aim is to identify the best practice for three relevant unknowns that characterize a wooden structural element: the geometry, through the survey and the BIM modelling; the density by means of the penetrometric tests (Resistograph and Woodpecker); the elastic module through direct and indirect ultra-sonic tests.

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“…Unfortunately, this is not possible in existing structures, for which density needs to be estimated. To this aim, several techniques have been tested and proposed, including, e.g., core drilling, screw withdrawal, needle penetration resistance and the analysis of the residue of a conventional drill [5][6][7]. According to the cited literature, these methods have been proven to be suitable for estimating the density of the wooden elements in situ but still require the extraction of material (coring was found to be the best method, and, of course, the bigger the core, the higher the correlation with the density) or only evaluate a relatively superficial area of the beam (needle penetration or screw withdrawal).…”

Section: Introductionmentioning

confidence: 99%

Density Estimation by Drilling Resistance Technique to Determine the Dynamic Modulus of Elasticity of Wooden Members in Historic Structures

Brunetti

Aminti

Vicario

et al. 2023

Forests

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(1) The assessment of the mechanical properties of old timber is essential for the proper maintenance of wooden structures. (2) Among the non-destructive properties, the dynamic modulus of elasticity is one of the best predictors of the mechanical characteristics of the members, but it requires the determination of wood density to be determined. (3) Thus, wood density was estimated by drilling resistance measurements, developing species-specific prediction equations for silver fir, chestnut and poplar. (4) The estimated density was combined with the stress wave velocity propagating longitudinally through the wooden piece, and the dynamic modulus of elasticity was calculated. (5) Medium-high coefficient determinations (R2 from 0.79 to 0.94) were found for density estimation, and medium coefficient determinations (R2 from 0.53 to 0.60) were found for the estimation of the static modulus of elasticity using the dynamic modulus.

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Improving density estimation in large cross-section timber from existing structures optimizing the number of non-destructive measurements

Cited by 18 publications

References 17 publications

Wood Density Determination by Drilling Chips Extraction in Ten Softwood and Hardwood Species

Wood Density Determination by Drilling Chips Extraction in Ten Softwood and Hardwood Species

Sustainable Assessment: A Contribution to Improve the Reliability of NDT on Old Chestnut Purlins

Density Estimation by Drilling Resistance Technique to Determine the Dynamic Modulus of Elasticity of Wooden Members in Historic Structures

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