RT info:eu-repo/semantics/article T1 Assessment of machine learning algorithm-based grading of Populus x euramericana I-214 structural sawn timber A1 Acuña Rello, Luis A1 Spavento, Eleana A1 Casado Sanz, María Milagrosa A1 Basterra Otero, Luis Alfonso A1 López Rodríguez, Gamaliel A1 Ramón Cueto, Gemma A1 Relea Gangas, Enrique A1 Morillas Romero, Leandro A1 Escolano Margarit, David A1 Martínez López, Roberto Diego A1 Balmori Roiz, José Antonio K1 Poplar K1 Timber grading K1 Defects K1 Sawing systems K1 Non-destructive testing K1 Strength class AB The efficiency of visual grading standards applied to structural timber is often inappropriate, and timber properties are either under or over-graded. Although not included in the current UNE 56544 visual grading standard, machine learning algorithms represent a promising alternative to grade structural timber. The general aim of this research was to compare the performance of machine learning algorithms based on visual defects, non-destructive techniques and sawing systems (“cut type”) with UNE 56544:1997 visual grading in order to predict the qualifying efficiency of Populus x euramericana I-214 structural timber. Visual evaluation, ultrasound and vibrational non-destructive testing, and sawing systems register (radial, tangential and mixed) were applied to characterize 945 beams. In addition, in order to retrieve actual physical-mechanical values, density and static bending destructive testing (EN-408:2011 + A1:2012) was also carried out. Several machine learning algorithms were then used to grade the beams, and their predictive accuracy was compared with that of visual grading. To do so, three scenarios were considered: a first scenario in which only visual variables were used; a second scenario in which “cut type” variables were also included; and a third scenario in which additional non-destructive variables were considered. Results showed a poor level of performance of UNE 56544:1997, with an apparent mismatch between the strength values assigned for each visual grade (established by the EN 338 standard) and the actual values. On the opposite, all algorithms performed better than visual grading and may thus be deemed as promising timber strength grading tools. PB Elsevier SN 0141-0296 YR 2022 FD 2022 LK https://uvadoc.uva.es/handle/10324/51750 UL https://uvadoc.uva.es/handle/10324/51750 LA eng NO Engineering Structures, 2022, vol. 254, p. 113826, DS UVaDOC RD 19-oct-2024