TECHNICAL NOTE: USING NONDESTRUCTIVE TESTING TO IDENTIFY PREMIUM GRADES IN SOUTHERN PINE AND DOUGLAS-FIR UTILITY CROSSARMS

摘要

Unlike lumber, wood utility crossarms are not currently available in premium grades that indicate a higher level of performance in service. Previous research has shown that nondestructive testing (NDT) techniques are able to predict performance properties of solid wood products with considerable accuracy. The aim of this study was to determine the suitability of NDT methods for predicting the stiffness and strength properties of wood utility crossarms and possibly aiding in the identification of a premium grade that exhibits higher average performance values. Samples of Douglas-fir and southern pine were subjected to multiple NDT technologies to estimate MOE. Each specimen was also measured for MOE and MOR with a static bending test. Bivariate correlations and corresponding R-2 values showed that Fibre-gen's Director HM200 and Metriguard's E-computer were the most accurate NDT devices among those tested for predicting both MOR and MOE. Means tests also suggested that the devices could possibly be used to identify a premium grade that shows significantly higher average performance values.