Situation
The 16-inch cement-lined water main was constructed in 1990, spanning underneath Robert Street Bridge over the Mississippi River in Saint Paul, MN. In 2024, the water main ruptured due to a combination of freezing and dead-head hydraulic conditions, causing substantial damage to the pipeline, pipe fittings, pipe supports and the concrete from Pier 3 to the South Abutment of the bridge.
The ruptured water main comprised of two sections, the first section spanned 510 feet from Pier 3 to Pier 4, and the second section spanned 250 feet from Pier 4 to the South Abutment of the bridge.