Materiales de Construcción, Vol 60, No 299 (2010)

The effect of fissures on the strength of structural timber

Miguel Esteban
Universidad Politécnica de Madrid, ETSI Montes, Spain

Francisco Arriaga
Universidad Politécnica de Madrid, ETSI Montes, Spain

Guillermo Íñiguez
Asociación de Investigación de las Industrias de la Madera, Madrid, Spain

Ignacio Bobadilla
Universidad Politécnica de Madrid, EUIT Forestal, Spain

Raquel Mateo
Asociación de Investigación de las Industrias de la Madera, Madrid, Spain


Detailed measurements of drying fissures were carried out on 28 pieces of gross cross-section structural Scots pine timber. Different parameters have been proposed to measure their magnitude: length, depth, thickness and slope of grain, as well as an index of area in the neutral axis plane (ratio of effective to total surface). The parameters of fissures have been related to bending strength, shear strength, modulus of elasticity and rupture energy obtained from mechanical tests, considering whether rupture is due to bending or shear. All of the fissures observed allows to classify the pieces as MEG according to the UNE 56544 standard. To quantify the magnitude of fissures the index of areas is proposed, while mechanical properties can be quantified by rupture energy. Analysis of the results does not show any relation between the fissures analyzed and the mode of failure, their magnitude and mechanical properties..


Timber; Mechanical Properties; Characterization; Drying Fissure

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