PUSHING A BRIDGE FOR HALF A MILE

This brief article describes the construction of the 890 m long bridge across Dornoch Firth, Scotland, by the "cast and push" method. Each week, 22 m of the post tensioned box is cast under cover in a factory at the tip of the south embankment. Concrete is placed in a 10 hour pour on a Friday, and the deck is pushed out in 400 mm increments by two 600 t rams on a Monday. The weekly construction cycle and long concrete pours have been made possible by using pre-welded rebar to the maximum permitted (about 40%), thus dramatically reducing steel fixing time, and the use of a 10 hour retarder in the concrete. All waste produced is pumped to a barge and dumped inland. The 42 weekly cycles will be completed in March 1991, when 15,000 t of bridge will be launched by sliding it on PTFE (polytetrafluoroethylene) sheets over 20 piers topped with temporary stainless steel bearings. The straight bridge has a vertical curve of 20 km so the initial push is 1% uphill, with the crown two thirds of the way across. This is one of the longest bridges to be built using the cast-push technique.

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  • Corporate Authors:

    INSTITUTION OF HIGHWAYS & TRANSPORTATION

    6 ENDSLEIGH STREET
    LONDON,   United Kingdom  WC1H 0DZ
  • Authors:
    • -
  • Publication Date: 1990-8

Language

  • English

Media Info

  • Pagination: p. 37
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00606612
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Mar 31 1991 12:00AM