Casco Bay Bridge Replacement

On September 27, 1996, the 560-ft long Liberian tanker, Julie N, carrying a cargo of heating oil, collided with the south bascule pier of the Million Dollar Bridge. The accident resulted in 4,000 barrels of oil spilling into the harbor, $43 million for the cleanup, and bridge repairs totaling $232,000. That one incident, coupled with the bridge’s deteriorated condition and functional obsolescence, underscored the urgent need to build a replacement. As part of the team selected to study the replacement bridge, Modjeski and Masters (M&M) developed the environmental impact statement and designed the replacement structure. One of our primary design considerations was how to prevent a repeat of the Julie N scenario.

We identified additional opportunities to make improvements with the new design: improve traffic operations and circulation, reduce long term maintenance costs, provide safe bicycle and pedestrian capability, and reduce delays to the Roadway and Shipping Channel Users.Our award-winning design neatly incorporated solutions to many of the identified challenges. At 285 feet, the bascule span is one of the largest of its type in North America. It provides horizontal clearance more than 100 feet wider than the old movable span, making the passage through the bridge safer for navigation. It provides a higher vertical clearance which decreases the number of openings of the span. M&M designed a state-of-the-art pier protection system to prevent, or at least minimize, any damage to the bridge, to the riverine environment, or to the vessel involved in the impact.