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Life-Cycle Engineering Services | EXPANDED

Modjeski and Masters is pleased to announce the acquisition of structural engineering firm Summit Engineering Group, Inc. Our combined engineering prowess and respective technical skillsets will enable us to provide streamlined design and construction solutions to best meet client needs.

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Casco Bay Bascule Bridge Replacement

| View Projects:USA Portland, ME

  • Client:

    Maine Department of Transportation
  • Service:

    Movable Bridges
  • Status:

  • Award Winner
  • Overview

    On September 27, 1996, the 560-foot 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. That decision had already been made. In fact, before it struck the Million Dollar Bridge, the Julie N passed between the piers of the new Casco Bay Bridge, the replacement bridge which was under construction.

    As part of the team selected to study the replacement bridge, Modjeski and Masters 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. Undoubtedly, there would be other accidents involving ships and the structure. Our challenge was to find ways to minimize the damage. 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. The result: a reduced number of delays to bridge users. We 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. Protected pedestrian/bikeways were also included with the widened deck and improved shoulders.

    Soon after the Casco Bay Bridge was opened, a 685-foot tanker transporting 11.3 million gallons of fuel struck the bridge. But this time, the fender system protecting the bridge absorbed the impact. There were no injuries to the crew, no oil was spilled, and no damage was done to the vessel. The Modjeski and Masters team had successfully created a design that accomplished one of the project’s primary goals. As part of our continuing relationship with the Casco Bay Bridge and the Maine DOT, we have recently completed an electrical and mechanical inspection of the structure.
  • Description

    Tasks Performed
    • New Structure – Design (Preliminary and Final)
    • Electrical/Mechanical Design
    • Electrical/Mechanical Inspection
    • Construction Support & Inspection

    Bridge Geometry
    • Length of Main Span – 285 feet
    • Total Project Length – 4,748 feet
    • Lanes on Structure – four lanes in addition to a pedestrian lane
  • Testimonial

    “…It saved our bridge and all the headaches that go along with it if there was an oil spill…” - John Buxton, Assistant Bridge Maintenance Engineer, MaineDOT, referring to the state-of-the-art fender system designed by Modjeski and Masters, Inc.
  • Credits

    Leon K. Huang, PE (Project Manager)
    Lance V. Borden, PE (Lead Electrical Engineer)
    Jeffrey W. Newman, PE (Lead Mechanical Engineer)
    Michael C. Irwin, PE (Lead Structural Engineer)