BOX GIRDER BALANCING ACT

Maine's new four-lane, 2,972-ft (906-m) Sagadahoc Bridge will replace the vehicular portion of the Carlton Bridge when it opens to traffic in October 2000. The project broke new ground as the state's first design/build project and broke a bridge span record in the process. To minimize the number of piers constructed in the water, designers made each span as long as possible. A total of 202 precast-concrete box girder segments were cast at a riverbank yard just upstream of the project. The precast cofferdam with a steel follower cofferdam attached, was floated into position above the previously drilled shafts at high tide. The superstructure was constructed in cantilever fashion because of the long span lengths needed, including the record-breaking 420-ft (128-m) span. Because durability is a major concern, the bridge incorporates features that ensure a long life with minimal maintenance. The 6,000 psi (41,370 kPa) concrete for the superstructure includes fly ash for decreased permeability and calcium nitrate for corrosion resistance. The superstructure is posttensioned both longitudinally and transversely. The replaceable asphalt wearing surface features a waterproof membrane, and the erosion-resistant granite cladding on the pier bases provides protection against the tidal zone of the Kennebec River and will break up floating ice. A 5-year warranty covers the bearings, sign and light supports, sign panels, luminaires, pavement and granite pier construction; while a 10-year warranty applies to the bridge deck joints and the waterproof membrane.

Language

  • English

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Filing Info

  • Accession Number: 00789039
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Mar 27 2000 12:00AM