Failure of a southern pine utility pole

A lineman had climbed a southern pine utility pole and was tightening a multiwire steel strand strung between it and an adjacent pole when the pole failed. The lineman fell to the ground with the pole and was physically and electrically injured and burned. Eyewitnesses reported that the failure occurred above the lineman and that the pole then broke again almost immediately at ground level. Estimates of the loads applied to the pole before the new strand was added and as it was being tightened have shown that, had the pole been sound, it would not have failed. Examination of the failed pole revealed that many stress concentrators contributed to the failure. These included a woodpecker hole, holes for bolts intended to support a transfomer and 'checks', i.e. radial cracks created by weathering. The pole was about 47 years old. The lineman filed an action in a Kentucky circuit court against the utility company which owned the pole. There then developed a web of claims and cross claims involving the cable television company which had employed the lineman, its parent company and several insurance companies. The case was settled after the opening statements in a jury trial had been made.

Keywords:

• Utility Pole
• Failure
• Wood
• Weathering