The reusability of decommissioned treated wood is primarily dependent on the residual strength of the wood after service. Determining the residual strength can provide useful information for structural design and reuse of the decommissioned treated wood. This study evaluated the residual strength of decommissioned chromated copper arsenate–treated utility pole wood. Eleven decommissioned southern pine (Pinus spp.) distribution poles and pole sections were evaluated, using small clear samples, for bending strength and stiffness across and along each pole. Results showed that the strength of the decommissioned treated wood varied across and along each pole and among the poles. Average modulus of rupture (MOR) was 80.9 percent of the typical MOR of longleaf pine (Pinus palustris) virgin wood, and average modulus of elasticity (MOE) was 83.9 percent of the typical MOE. Average MOR of the samples in the outer surface (first test zone) was 7.5 percent lower than the average MOR of the adjacent samples toward the pith (second test zone) on each side of the pole surfaces, but average MOE showed no significant difference between the two zones. Older poles lost more strength in the first test zone. Results demonstrated that spiral grain substantially reduced the strength of utility pole wood.
Contributor Notes
The authors are, respectively, Assistant Professor, Calhoun Research Sta., Louisiana State Univ. Agric. Center, Calhoun (cpiao@agcenter.lsu.edu); and Project Leader, USDA Forest Serv., Southern Research Sta., Pineville, Louisiana (lgroom@fs.fed.us). This paper (2009-255-4053) is published with the approval of the Director of the Louisiana Agricultural Experiment Station. This paper was received for publication in November 2009. Article no. 10708.