Assessment of wood utility pole climbability using psychophysical and mechanical measurements

The issue of climbability has been raised on several occasions for more than a decade in North America. Presently, climbability is estimated from the pole hardness measured by the Pilodyn measurements (6 J). However, the use of Pilodyn measurements to discriminate the pole hardness value is criticized by climbers, who claim that the Pilodyn hardness measurement is affected by species-treatment combinations and that it does not reflect gaff penetration or climbability. Furthermore, climbability evaluations have been conducted in which test poles were climbed by linemen, and corresponding subjective ratings were recorded. However, the ability of psychophysical measurements to accurately discriminate close hardness pole values and to differentiate species-treatment combinations at specific hardness levels have not yet been fully documented. The aim of this study is to evaluate the psychophysical perception of linemen and the mechanical measurements of gaff penetration and gaff impact during the climbing of different wood species and treatment combinations in order to compare these results with Pilodyn measurements within a precise range of pole hardnesses, to study the relationships between these variables, and, finally, to propose various design guidelines for the development of a better tool for the evaluation of climbability.