Evaluation of the Load-Carrying Capacity in Bending of Large Cross Section “Pitch Pine” Beams in Standing Structures

Abstract:

This paper deals with the procedure followed in order to define a visual grading protocol to determine the mechanical properties of existing old pitch pine timber beams with large sections. The commercial name pitch pine comprises several species in the group of southern yellow pines, being the Longleaf pine or Georgia pitch pine (Pinus palustris) the most important. Old growth Pinus palustris, was very much appreciated for its rigidity, density, strength properties and natural durability. In Spain, many of the buildings constructed with this timber (named as pino tea) are nowadays under rehabilitation processes which, in some cases, will change the previous use of the building. All these interventions require understanding the mechanical properties of the timber. The structural properties of the aged pitch pine timber are unknown and there is not any European stress grading standard to enable the classification of the existing elements. For this reason, a total of 45 large section pitch pine pieces were visually analyzed and graded according to Spanish standard UNE EN 56.544 [. After this, the beams were tested according to UNE EN 408 [ in order to determine their modulus of rupture and flobal modulus of elasticity. All beams were tested keeping their original positions in the building and a new classification system for old beams is proposed based on a reduced number of chief visual grading parameters and taking into account their position into the beam.

• Periodical: Advanced Materials Research (Volume 778)
• Pages: 410-417
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.778.410
• Online since: September 2013
• Authors: Manuel C. Touza Váquez, Azahara Soilán Cañás, David Lorenzo Fouz
• Keywords: Pinus palustris, Pitch Pine, Rehabilitation, Structural Assessment, Timber, Visual Grading

References

[1] UNE 56544. Visual grading of structural sawn timber. Coniferous timber.

[2] EN 408. Timber structures - Structural timber and glued laminated timber - Determination of some physical and mechanical properties.

DOI: 10.3403/30159970

[3] L. S. Early. Looking for Longleaf: The Fall and Rise of an American Forest. The University of North Carolina Press, Chapel Hill, North Carolina, (2004).

DOI: 10.3375/0885-8608(2006)26[317b:lfltfa]2.0.co;2

[4] M. Esteban; F. Arriaga; G. Iñiguez; I. Bobadilla; R. Mateo. The effect of fissures on the strength of structural timber. Mater. Construcc., vol. 60, nº 299 (2010), pp.115-132.

DOI: 10.3989/mc.2010.48208

[5] F. Arriaga; M. Esteban; G. Iñiguez; R. Argüelles; I. Bobadilla. The effect of wanes on the bending strength of solid timber beams. Mater. Construcc., vol. 57, nº 288 (2007), pp.61-76.

DOI: 10.3989/mc.2007.v57.i288.65

[6] N. Itagaki; H. Mihashi; S. Ninomiya. Knot's influence on tensile strength of timber. 5th World Conference on Timber Engineering. Proceedings. Vol. 2 (1998), pp.780-781.

[7] Mitsuhashi, Kohsaku; Poussa, Matti; Puttonen, Jari. Method for predicting tension capacity of sawn timber considering slope of grain around knots. Journal of wood science, vol. 54, nº3 (2008), pp.189-195.

DOI: 10.1007/s10086-007-0941-5

[8] V. Bano; F. Arriaga; A. Soilán; M. Guaita. Prediction of bending load capacity of timber beams using a finite element method simulation of knots and grain deviation. Biosystems engineering, vol. 109, nº 4 (2011), pp.241-249.

DOI: 10.1016/j.biosystemseng.2011.05.008

[9] H. Cruz, D. Yeomans, E. Tsakanika, N. Maccioni, A. Jorissen, M. Touza, M. Manucci, P. Lourenço. Guidelines for the on-site assessment of historic timber structures. International Journal of Architectural Heritage: Conservation, Analysis, and Restoration Forthcoming (2013).

DOI: 10.1080/15583058.2013.774070

[10] UNI 11119. Culture heritage - Wooden artefacts - Load bearing structures - Onsite inspections for the diagnosis of timber members.

[11] EN 844-9. Round and sawn timber. Terminology. Part 9: Terms relating to features of sawn timber.

DOI: 10.3403/01125804

[12] EN 13183-1. Moisture content of a piece of sawn timber - Part 1: Determination by oven dry method.

DOI: 10.3403/02558468

[13] EN 384. Structural timber - Determination of characteristic values of mechanical properties and density.

[14] EN 338. Structural timber –Strength classes.

[15] F. Rinn. Basics of micro-resistance drilling for timber inspection. Holztechnologie 53 -3 (2012), pp.24-29.