Composite Utility Poles
Composite Utility Poles have been under development for a number of years. Replacing the existing wooden poles with fiberglass composites have many long-term advantages and yet have many obstacles to implementation. These poles are pultruded and use polyester resin and E-glass reinforcement. UV additives are employed to minimize one of the Achilles heels of composites resin.
Advantages of composite poles over wood are numerous. Composite poles have a lifespan of roughly 80 years versus the 25-30 years for wood, due to rotting issues. These rotting issues with wooden poles are combatted with chemical additives that are sometimes corrosive and toxic. Composite poles have a weight advantage, as they weigh about two-thirds less than a wooden pole, which allows for easier transportation to the jobsite and reduced equipment requirements for installation. Due to their controlled and known construction, composite poles have physical properties that are more stable and reliable over the duration. Composites are intrinsically non-conductive, which is ideal in this application.
Replacing an existing material in a current application always brings hurdles and challenges for acceptance. The wooden poles are known by purchasing, engineering, installation, and line utworker crews. Composite poles have a higher upfront cost, though long-term savings are significant. As the educational resources reach those affected, the transition will take place and composite utility poles will become widespread.
Pultrusion Processing
Pultrusion is a continuous process similar to steel or plastic extrusion for creating products with a constant cross section. Examples of these products are rod stock, structural shapes, beams, channels, pipe, tubing, fishing rods, and golf club shafts. High structural properties are created because of the extremely high fiber loading afforded with this process.
A resin bath impregnates the continuous strand fiberglass roving, mat, cloth, or surfacing veil before it is pulled through a steel die. This die is responsible for the shape, consolidating the reinforcement, and controlling the fiber/resin ratio. This die is heated to cure the resin as it passes through and out to the pulling mechanism which controls the speed of processing.
Advantages of this process include low labor costs due to the ability to automate. It also allows for cross-sectional shapes ranging from simple to very complex. Very high strengths can be achieved due to the high fiber loading.
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