Not your typical river crossing

Instead of a below-grade inverted siphon that could plug and require costly maintenance, Kentucky’s second-largest sewer utility opted to go over Willoughby Creek. A bridge also eliminated having to install pumps along the pipeline’s 7-mile stretch. The 700-foot steel-and-pipe bridge was at grade at each abutment and 30 feet above ground at the highest point.

Pipe manufacturer Hobas USA Inc. provided two custom-designed flanged ends to connect to a special expansion section that accommodates thermal expansion between the steel bridge and the fiberglass-reinforced, polymer mortar pipe.

Steel cradles support 102-inch centrifugally cast, fiberglass-reinforced, polymer mortar pipe on the aerial portion of the Sanitation District No.1 of Northern Kentucky’s tunnel project. The structure is about 13 feet wide.

Each joint was air-tested at 5 psi to ensure leak-free service. All sections have performed well since the tunnel went into service in April 2012.

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