Rungsundet Bridge

The Rungsundet Bridge provides a mainland connection to the island of Bremanger in western Norway, crossing the strait between Kolset on the mainland and Krakevik on Rugsund Island. Designed as a three-span, free cantilever concrete box girder bridge, the structure has a total length of 311 meters (1,020 feet).

Originally engineered using normal density concrete, the bridge was redesigned following a peer review by Norconsult AS. The revised design incorporated Stalite Lightweight Aggregate in portions of the superstructure, significantly improving structural efficiency.

By reducing dead load, the lightweight concrete allowed the main span to increase from 172 meters (564 feet) to 190 meters (623 feet). This longer span enabled foundations to be placed in shallower water, simplifying construction, reducing pier heights, and lowering overall foundation costs.

A preliminary cost comparison showed the lightweight concrete alternative to be at least 7 percent less expensive than the original design. When bids were received, the lightweight alternative proved to be 15 percent lower in cost, confirming both structural and economic advantages.

The Rungsundet Bridge followed the successful use of Stalite Lightweight Aggregate on the Raftsundet Bridge and further demonstrated the viability of pumpable structural lightweight concrete for long-span bridge applications in Norway.