Researcher Yaiza Fuentes García, a Building Engineer from the University of Granada, defended her doctoral thesis yesterday titled “Mechanical Characterization of Poplar Clones MC and Luisa Avanzo and Their Viability for Structural Laminates” in the Assembly Hall of the School of Building Engineering of the University of Granada (UGR). The thesis was carried out within the UIMA laboratory (Andalusian Structural Wood Research Unit) of the UGR, in collaboration with the PEMADE laboratory (Platform for Structural Wood Engineering) of the University of Santiago de Compostela in Lugo, the Andalusian Institute of Agrarian Research and Training (IFAPA), the Wood Construction Research Group of the Polytechnic University of Madrid, and the LABOMAP group of ParisTech University in Cluny (France).

The thesis performed a characterization of the mechanical properties of poplar wood at the Spanish level, restricted to the clonal varieties MC and Luisa Avanzo, the most abundant in Granada and Andalusia. Through rigorous mechanical tests on large samples, it was concluded that poplar wood meets the regulatory requirements of a T10 resistance class (EN 338), meaning that its structural use is entirely viable. The characterization of the wood was comprehensive, including non-destructive testing (NDT) and destructive testing (DT), covering tension, bending, and compression tests in directions parallel and perpendicular to the fiber.

This research has allowed the Spanish committee of UNE to approve a visual quality MEF (Hardwood Structural Timber) through the Spanish standard ‘Visual Classification of Sawn Timber for Structural Use. Hardwood’ (UNE 56546:2024) and the European committee ‘Timber Structures. Solid Timber. TG1 Task Group for Grading and Strength Properties’ (CEN/TC124/WG2/TG1) to approve the assignment of this resistance class (EN 1912). With this historic milestone, specifiers are guaranteed reference values for their structural calculations and project security.

 

 

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The thesis also addressed the research on new structural laminated products made from poplar wood, with the aim of giving new uses to this wood, increasing its added value through knowledge, and opening new market niches. Specifically, the thesis investigated the mechanical properties of laminated beams (GLT) and cross-laminated timber (CLT) made from poplar wood, and also mixed with other woods such as pine and French oak. The result is that these structural laminates, whose demand in the sustainable construction market is growing by more than 300%, are entirely viable from a scientific point of view. Regarding the laminated beam, a GL20h resistance class was obtained. In the case of cross-laminated timber, four-point bending and shear rolling tests were performed, correlating the results obtained with techniques such as Digital Image Correlation (DIC) and numerical models. The introduction of poplar in mixed CLT panels allows for great efficiency in terms of modulus of elasticity, strength, and rigidity, with a considerable reduction in weight.

The doctoral thesis was directed by Dr. Francisco Rescalvo and Dr. Elísabet Suárez of UIMA-Granada, from the Departments of Structural Mechanics and Architectural Constructions, respectively.

The research work was carried out with the collaboration of forest owners grouped in Marjal under the direction of COSE, as well as with the funding of the European project LIFE Wood for Future and the LightTimber project of the Ministry of Ecological Transition and Demographic Challenge.

The experimental development of the thesis involved complex logistical tasks for the acquisition of wood, cutting, transportation, sawing, and drying in six locations across Spain, which were carried out with the collaboration of the Riojan company Bosques y Ríos, Marjal, and local sawmills in each area.

This research has been partly transferred to the UGR spinoff company, Iberolam Timber & Technology, a society constituted by numerous Andalusian forest owners as well as researchers from the LIFE Wood for Future project, which has already started the installation of a factory for structural wood products in Granada for sustainable construction, thus clearly and emphatically fulfilling one of the University’s objectives, the Transformation of the Environment.

Contact:

Yaiza Fuentes García

yaizafg@ugr.es

608 29 11 22

Group UIMA-UGR

www.uima.es

uima@ugr.es