WOOD HARDNESS OF UTILITY POLES - PART 1 - STUDY OF PHYSICAL PARAMETERS IN CORRELATION WITH THE LINEMENS PSYCHOPHYSICAL PERCEPTION OF WOOD POLE HARDNESS

The primary aim of this study was to measure physical parameters in co rrelation with wood pole hardness as perceived by linemen. Based on th eir perception of psychophysical hardness, a group of linemen classifi ed a set of poles during three series of tests. The results reveal the importance of limiting field measurements in order to minimize variab ility in the physical characteristics of the poles over time. Although this limitation improved reproducibility in the measurement of percep tion, variations in the classification were still observed in the resu lts. The three series of tests revealed a relation between the psychop hysical perception of hardness and gaff penetration and impact data. T he maximum variations of the gaff penetration and gaff impact data for each hardness increment occur at different points along the psychophy sical perception scale; gaff penetration varies more than the impact f or the poles considered to be soft, whereas the reverse is true for th e hard poles. By combining these parameters mathematically into a wood hardness indicator, a better correlation was obtained for the hardnes s perceived by the linemen than for the Pilodyn penetration readings ( r = 0.986 versus r = -0.927 for the Pilodyn). This improved degree of correlation is due to the fact that the hardness indicator is based on the data from the climbers used by the linemen to establish their per ception. Moreover, a substantial increase in the impact energy with th e increase in wood hardness perceived by the linemen was noted. Finall y, there is no correlation between variations in the strain and gaff p enetration speed and the wood hardness as perceived by the linemen.