Burnside Bridge Main Span Rehabilitation

Owner: Multnomah County

Portland, OR
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January 2006 - January 2008
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Project Details

Unlike every other bridge that features a Strauss Trunnion Bascule draw span, the Burnside Bridge’s roadway is concrete, and the bridge’s 3.8 million pound counterweight is one of the largest in the country. This fact plus the age of the bridge caused unique challenges when it came time to rehabilitate the bridge’s main span. As the prime contractor, AAC’s work included removal and replacement of over 400 cubic yards of bridge deck; replace corroded road stringers; retrofit lift drive mechanical systems; replace counterweight link arms; and rehabilitate existing live-load bearings. AAC was required to perform extensive concrete demolition to facilitate replacing and retrofitting the bridge components. In one particular instance, AAC wire sawed a large portal in the side of the concrete pier to facilitate material installation.

The bridge could only be completely closed on weekends, which meant work done during this time was conducted around the clock. When the bridge was open for use, one leaf had to be operational at all times, a specification that required AAC to replace all motors and brakes at the same time that the concrete roadway was being replaced—a task that required a high degree of coordination. AAC accomplished this by using counterbalance technique where water was placed in a temporary containment located at the end of the span as concrete was removed.

Project Highlights

  • 3.75 million pound counterweight supported by complex rigging system while detached to replace trunnion pins & bearings.
  • Installation of seismic restrainers.
  • Installation of lift span motors, brakes and controls.
  • Replacement and repairs of corroded steel.
  • Installation of electrical systems.
  • Installation of storm water collection and treatment facilities.
  • New counterweight link arms.
  • Gear and bearing repairs.

Project Photos

Awards

  • 2008 Awards

    • Award
      DJC 2008 Top Projects Awards
      Open
      DJC 2008 Top Projects Awards
      The Daily Journal of Commerce awarded AAC second place in the Transportation Category for the Burnside Bridge Main Span Rehabilitation. The award recognized the project's success and innovation despite unique challenges to rehabilitate the bridge's main span with unexpected obstacles. 

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