Rehabilitation of wooden utility poles with sprayed-GFRP composites

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Wood poles have substantial advantages over other construction materials because wood is renewable, sustainable, generates less greenhouse gases during manufacturing and provides a long-term repository for atmospheric carbon. Wood utility poles on average serve for 30 to 40 years; however, this service life can be shortened due to several factors including decay, mechanical damage, weathering and changing design circumstances. Even though a preservative treatment and regular maintenance can extend the pole life, at some point, the pole loses its load carrying capacity and becomes vulnerable to failure, which leads to power outage, costly repair and other economic losses. For example, Manitoba Hydro has over 600,000 power distribution poles across Manitoba. If 3% of these poles need replacement annually, the cost can approach $5.4 million. On the other hand, rehabilitation of these poles will not only save time and money but also will reduce the consumption of trees and cost of treated wood disposal. In the last two decades, fibre-reinforced polymer (FRP) materials have been successfully used in the construction and rehabilitation of civil infrastructure due to their high strength and corrosion resistance. Current FRP rehabilitation of concrete and wood structures are conducted by providing FRP wraps or jackets around the damaged area. However, a relatively new technique, sprayed-FRP composites, is proposed to rehabilitate deficient wood poles. This technique offers advantages over conventional FRP jackets, such as easier application, less surface preparation, less vulnerability to debonding, higher effectiveness on irregular and difficult-to-access surfaces, better deformability, and better cost effectiveness. The objective of this study is to develop design methodologies for rehabilitating wood utility poles using sprayed-FRP composites. The proposed work includes both experimental tests on full-scale poles up to failure under different rehabilitation scenarios and analytical investigation using finite element analysis. This will lead to refurbished wood utility poles with improved performance, better durability, and that incur fewer maintenance costs for hydro distribution agencies.