Carillion for Highways Agency
A249 Iwade Bypass to Queenborough Improvement Scheme - a DBFO Contract for the construction, operation and maintenance of the A249 from the M2 junction to Sheerness Docks.
The most prominent feature was the new Sheppey Crossing – a high level viaduct of 19 spans carrying the rerouted A249 dual carriageway over The Swale – the channel separating the Isle of Sheppey from the mainland of North Kent, local roads and the Sittingborne to Sheerness railway line.
Cass Hayward Role(s)
- Options review and design for tender
- Detailed design of viaduct superstructure, substructure, piling and river caissons
- Detailed design of steelwork launch scheme including launch nose and pier top temporary crossheads.
- Viaduct Designer Site Representative.
- Works value £30m
- Completed June 2006
- 1.25km long on a curved alignment
- Crest of the road 29 metres above high water level
- 92.5m maximum span over The Swale
- Linear variation of successive span lengths and associated tapering depth
- Bridge launching to minimise impact on environmentally sensitive flood plain
- The launch phase over the main span achieved a 92.5m freestanding (curving) cantilever which is understood to be the longest achieved in the UK
- River foundations are massive gravity bases to resist ship collision
- I Struct E –Award for Transportation Structures - Winner
- BCSA - Steel Design Award
- ICE (South East England) - Thomas Brassey Award