Effect of Inspection Holes on Flexural Properties of Douglas-Fir Utility Poles

Routine inspection of wood utility poles to detect internal decay involves drilling holes at or about the ground line. While these holes are useful for detecting internal decay, their presence raises concern among engineers about their potential effects on pole flexural properties. The effect of inspection holes on flexural properties was studied on 92 Douglas-fir poles. Drilling up to six 20-mm-diameter inspection holes had no significant effect on flexural properties, indicating that inspection does not adversely affect pole condition.