Analysis of the effect of volume on the bending strength of the Spanish scot and laricio pine timber

Abstract

Since the beginning of the XX century it has been recognized that the bending strength of timber is affected by the size of the specimen. In the present work the influence of depth (h) and thickness (t) on the characteristic bending strength (f_k) of both Scot (Pinus sylvestris) and Laricio (Pinus nigra) pine Spanish grown timber is assessed. 1.733 pieces of both species ranging in size from 100x40x2500 mm to 200x70x4.500 mm and especially sampled for this work, have been tested for bending in accordance with UNE EN 408 standard. In both species, the influence of depth and thickness on the characteristic bending strength of timber is highly significative but different between them and lead to conclude that the effect of the species is also significative and thus that the proposition of general values should be done cautiously, avoiding extrapolations. It is also concluded that, for both species, the effect of thickness seems to be highly significative and thus shouldn’t be ignored by the European standards. Finally, the convenience of revising the present depth factor considered in UNE EN 384 and UNE ENV 1995-1-1 standards is also suggested.