The effect of wanes on the bending strength of solid timber beams


  • F. Arriaga Martitegui Universidad Politécnica de Madrid
  • M. Esteban Herrero Universidad Politécnica de Madrid
  • R. Argüelles Álvarez Universidad Politécnica de Madrid
  • I. Bobadilla Maldonado Universidad Politécnica de Madrid
  • G. Íñiguez González Universidad Politécnica de Madrid



timber, structures, defects, wanes, visual grading


A theoretical analysis is conducted to determine the effect of wanes on the bearing capacity of timber in light of the reduction they entail in cross-sectional area compared to fully rectangular sections. The concomitant loss of bending strength is likewise evaluated. Parallel tests are run on 84 samples —51 with wanes— of large section, Scotch (Pinus sylvestris L.) and Corsican (Pinus pinaster Ait.) pine beams taken from old buildings. The bending strength, modulus of elasticity and density are found in accordance with European standard EN 408.
The mechanical properties of the specimens with and without wanes are found to be very similar, and no statistically significant differences are recorded. The effect of the decline in section may be offset by greater continuity of surface fibers and the section shape effect. One practical consequence of this finding is that (within certain limits) wanes may be disregarded when grading large section timber beams in existing structures, where this flaw is very common; this in turn would reduce the high percentage of rejected beams imposed by the present visual grading standards.


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How to Cite

Arriaga Martitegui, F., Esteban Herrero, M., Argüelles Álvarez, R., Bobadilla Maldonado, I., & Íñiguez González, G. (2007). The effect of wanes on the bending strength of solid timber beams. Materiales De Construcción, 57(288), 61–76.



Research Articles