TV tower composite repair: High-rise in Hawaii

Comptek Structural Composites (Boulder, Colo.) and Boulder-based subsidiary Aero Solutions LLC have tackled some daunting telecom tower repair challenges that Comptek contends could not have been met without the company’s unique composite materials and application methods (see “Composites the clear choice in telecom tower rehabs,” under “Editor’s Picks,” at top right). A good example is the repair of the 175-ft/54m tall KHON television broadcasting tower. Although the tower’s height presented no unusual barriers to success — Aero Solutions regularly tackles jobs on towers as high as 500 ft/152m) — the fact that the tower was mounted atop a 42-story building in downtown Honolulu, Hawaii, seriously raised the stakes.

Reportedly, the tower was so badly corroded and deteriorated that Honolulu officials had condemned it. Worse, revised building codes prevented construction of a replacement on the building. The television station would have had to find an alternative site in a much less desirable location.

Aero Solutions designed a carbon composite repair solution for the tower, featuring unidirectional carbon fiber, aligned parallel to the tower axis and carefully bonded to the entire outer surface of the steel monopole, followed by outer hoop wraps of uni carbon over 40 percent of its surface, to ensure structural integrity. A cement-based grout injection followed, to provide additional stiffness to the monopole. (Materials and grout-pumping equipment had to be delivered by helicopter.) Once stabilized, the tower was wrapped with Comptek’s water-activated polyurethane prepreg as an outer weather-tight layer.

“Composites delivered a miracle in that situation,” says Comptek CEO Jim Lockwood. “There simply was no other alternative.”