Steel poles help electrify Great White North

Mark Richards, Valmont Industries

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Valmont Industries Inc. recently completed the design and construction of 530 steel structures for a 230-kilovolt transmission line from Fairbanks to Healy, Alaska, one of its largest utility projects ever. Additionally, conditions for the Alaska project were more severe than in any other utility project faced by the company.

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Valmont’s utility customer, Golden Valley Electric Association Inc. of Fairbanks, put out the bid as part of its effort to upgrade the existing transmission line and provide more power to the Fairbanks area. Bid specifications requiring materials that would withstand temperatures ranging from 75 below in the winter to 100 degrees above in the summer required Valmont to use some innovative techniques. One example of this is the fact that the structures were not placed directly on the ground but on pilings; therefore, Valmont needed to fabricate clamps to hold the structures to the pilings. Another innovation was a ball and socket type hinge that was included at the base of the structures; so, if the structure ever needed to be taken down for whatever reason, the structure could pivot and be lowered to the ground. (The “ball” in the ball and socket joint is actually made of flat plates, put together to form a ball.)

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Valmont used 12 million pounds of steel on the $12 million project, and kept Valmont employees busy at four manufacturing plants: Tulsa, Okla.; Jasper, Tenn.; Valley, Nebr.; and Monterey, Mexico. Full scale testing occurred on the structures at the Electric Power Research Institute’s Haslet, Texas, testing site in late 2002. Tests included the structures’ ability to withstand the wind, ice, snow and other variables that would affect the load on the structures in the Alaska environment. Once testing was completed, the poles, which ranged from 100 to 167 feet tall, were delivered via rail to Seattle, where the rail cars were loaded on barges and transported via sea to Anchorage and then put back on rail to Fairbanks.

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Most of the structures are already in place; Golden Valley, who is working with outside contractors for the installation of the structures, is currently working on the remaining 10 percent. Due to the ruggedness of the territory, Valmont provided these remaining frame structures with bottom legs in five-foot increments, so the leg frames could be adjusted to match the uneven terrain; all of those will be set by helicopter. Much of the earlier installation had to be done in the winter months, due to the ground turning to swamps and bogs in the summer. Even so, an ice road needed to be created (spraying water on the area until there is ice several inches thick) in order to access some of the locations where structures were installed.

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At one point the transmission line spans the Chena River. The structures crossing the river have a back-up, storage battery system. Energy is pulled from the line to charge the batteries. If power is interrupted, the battery backup can supply full power to the line for about 20 minutes. Thousands of batteries are involved, making this the largest battery back-up system of this kind.

Richards is president of Valmont’s Engineered Support Structures division. Valmont is a global leader in engineered structures for the utility, transportation, lighting and wireless communication markets. Valmont currently has manufacturing facilities in 14 countries and is publicly traded on the New York Stock Exchange under VMI. Richards can be reached at 402-359-2201 or mrichards@valmont.com.

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