Maintenance Decisions for Inground Decay of Power-Supply Timber Poles

Timber poles are widely used for distributing electricity in rural areas, mainly in developing countries. The improved reliability of timber poles is extremely important as the breakdown or failure of any one of these poles can result in millions of dollars in lost revenue and restoration costs. The losses can include production loss, loss of property, or even loss of life. The reliability of such poles depends on a complex combination of age, usage, durability of timber, environmental factors influencing the deterioration process, and most important, maintenance actions carried out through the lifecycle of the poles. This paper focuses on developing an optimal maintenance model that predominantly captures the inground decay of timber poles, and on developing a mechanism for measuring these factors. The developed maintenance model is then illustrated with numerical examples. Analysis of failure data shows that most of the failures of timber poles are due to a decrease in timber strength and peripheral dimensions at or below ground level. The results from this research could be useful for maintenance and replacement decisions regarding inground timber components used in the utility, construction, railway, and transportation sectors.