Failure analysis of utility poles: a review of material deficiencies, environmental effects, structural performance, assessment techniques, and design considerations

Utility poles are the backbone of the electricity grid and a key enabler of a carbon–neutral economy, as they connect renewable sources like solar energy to homes and businesses. The number of such utility poles in each country is huge, and so is a significant infrastructure value. In Australia, for example, the current network consists of approximately 7 million utility poles made from wood, concrete, steel, steel–concrete composite, or fibre-reinforced polymer (FRP). While the current grid plans normally do not aim to increase this number of poles, as underground grids are more effective, replacing the current poles with underground assets is cost-prohibitive. So, there is a need to hold these poles in use and continuously replace the aged ones with new, durable poles. This study presents a comprehensive review of failure analysis for different types of poles. The failures can be grouped into three main categories: material-related problems, environmental degradation, and structural response, including cyclic load effects. Understanding these failure categories is important for explaining how poles behave over time and for planning proper maintenance or replacement strategies. It is concluded that future research should prioritise accelerated ageing studies (e.g., the relation between observed degradation and remaining structural capacity). Furthermore, the optimum pole type varies depending on factors such as capital investment, workforce experience, material availability, structural loads, environmental exposure, maintenance demands and associated costs. Lastly, assessment techniques, selection criteria, design considerations and future research directions are outlined.