Bending Strength and Stiffness of Portuguese Maritime Pine Utility Poles

The Civil Engineering Department of the University of Coimbra set up a project with the purpose of grading and characterizing Portuguese maritime pine utility poles. To achieve the aim of this project, 64 utility poles that met the requirements of Comite Europeen de normalization EN14229 were collected in the central coastal region of Portugal. The utility poles were characterized according to various anatomic and geometric characteristics: the number of knots, the amount of taper, the nominal diameter, and the rate of growth. Each utility pole was also tested in bending. From these tests, the bending strength and modulus of elasticity were determined. The results obtained were in line with previously published results for utility poles from other species. In addition to this, wood samples were collected from each specimen to determine the moisture content and density. The correlation coefficients between the bending strength and modulus of elasticity were determined, as were the coefficients between the bending strength and the anatomic and geometric characteristics. From this analysis, it was concluded that the properties that had a closer correlation with bending strength were those of modulus of elasticity, density, and taper. The correlation coefficient between bending strength and the set of geometric and anatomic characteristics and density was determined by a multiple linear regression, and it was concluded that this set of parameters may be used for nondestructive evaluation of the utility poles.