Abstract

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.

Highlights

  • To retrofit the existing timber structures with renovation and restoration works, it is previously necessary the characterization of wood singularities, biologic degradation, and the estimation of the mechanical properties [1,2,3,4,5,6]

  • This paper aims to obtain accurate estimation models for wood density in existing structures using the easy to use drilling chips extraction technique

  • Density obtained from drilling residue was not statistically significantly different between radial and tangential directions avoiding take into account direction when measuring

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Summary

Introduction

To retrofit the existing timber structures with renovation and restoration works, it is previously necessary the characterization of wood singularities (knots, cracks, etc.), biologic degradation, and the estimation of the mechanical properties [1,2,3,4,5,6]. Includes accurate, dependable and easy to use techniques for estimation of timber mechanical properties in the assessment of existing timber structures [7,8,9,10,11]. There are several NDT techniques, sometimes considered SDT, to estimate wood density [26–. 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. 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

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