Incrementally launched concrete bridges

This article is Current Practice Sheet No. 151 prepared by the Concrete Bridge Development Group. The economics of incremental launching in concrete bridge construction make it a suitable technique where the total deck length is more than 200m and where construction is at a high level over difficult or obstructed ground. An incrementally launched bridge must be of constant depth and have an alignment that is of constant curvature in both plan and elevation. The easiest form to create is that of a single-cell box. Unit lengths should be chosen to suit the particular span arrangement. Steel moulds should generally be used, with each mould casting 15-50 units. Ideally the whole bridge should be cast in one length from a single area behind one of the abutments. The foundations for this casting area would generally be piled. A typical weekly casting cycle is outlined. In order to limit the movement and shears in the deck as it is launched, it is necessary to have a launching nose attached to the front of the bridge. This consists of a braced, steel twin-plate girder with a length approximately 70% of a typical span. The units should be cast on a low-friction sliding surface. At each pier, the deck should slide over temporary bearings. As it passes over the piers, the deck will experience a total reversal of moments. The launching prestress must be designed to carry this range of moments.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00105317
• Authors:
  • Bourne, S
• Publication Date: 2007-7

Language

• English

Media Info

• Pagination: 7-8
• Serial:
  • CONCRETE
  • Volume: 41
  • Issue Number: 6
  • Publisher: THE CONCRETE SOCIETY
  • ISSN: 0010-5317

Subject/Index Terms

• TRT Terms: Bridge decks; Bridges; Concrete; Construction; Launching
• Uncontrolled Terms: Guidance
• ITRD Terms: 3455: Bridge; 3482: Bridge deck; 4755: Concrete; 3655: Construction; 9104: Guidance; 3412: Launching (by sliding)
• Subject Areas: Bridges and other structures; Construction; Design; Materials; I24: Design of Bridges and Retaining Walls; I32: Concrete; I53: Construction of Bridges and Retaining Walls;

Filing Info

• Accession Number: 01079649
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD
• Created Date: Oct 22 2007 10:21AM