Abstract
Wooden crossarms play a major role in supporting electric distribution lines in North America, but relatively few data exist on their condition as they age. The residual capacity of Douglas-fir crossarms in service in western Oregon for 45 to 60 years was investigated. Arms were sampled for residual preservative retention, the presence of visible decay fungi, and residual flexural properties; these results were then compared with three nondestructive tools. A majority of the arms tested had preservative levels well below those required for new arms, but only one decay fungus was isolated, and only five arms removed and dissected had any evidence of visible internal decay. Moduli of rupture for the arms were generally below the minimum levels required by national standards, but most still retained at least 67 percent of this value. Nondestructive evaluation tools were generally poorly correlated with flexural properties, possibly because of the heavily weathered and checked exterior condition.
Three New Nondestructive Evaluation Tools Based on High Flux Neutron Sources
