Turnpike Bridge, Fenstanton
About the project
This contract involved the near complete rebuild of a bridge and the replacement of a nearby culvert in the village of Fenstanton, adjacent to the A14 in Cambridgeshire.
- Project value
- January - July 2017
- 25 Weeks
Key aims and challenges
Danaher & Walsh was awarded the contract by Skanska, who were (and are) a highways term contractor to Cambridgeshire County Council.
Turnpike Bridge is located on Huntingdon Road in Fenstanton – the main route into the village from for eastbound traffic from the A14. It crosses Hall Green Brook, a small local watercourse.
Before works commenced, a full road closure and diversion route were implemented. A bridge was constructed to safely carry pedestrians for the duration of the works. As numerous services traverse Turnpike Bridge, these also had to be temporarily diverted by slewing them under the temporary bridge.
A scaffold-based crash deck was installed to prevent debris or pollution from entering the watercourse. This also served as a working platform for the parapet wall works. The original carriageway and bridge deck was demolished and removed from site.
The new bridge design involved installing 12 CFA piles (six each side) behind the existing bridge abutments. Two concrete capping beams were then cast in-situ on top of the rows of piles. 26 precast concrete beams were then carefully lifted into place, spanning between the two capping beams. The two heaviest of the precast beams (the edge beams) weighed around 15 tonnes each, so lifting operations had to be carefully planned and safely managed.
A reinforced concrete deck was then constructed on top of the precast beams. Reinforced concrete parapet walls were also constructed. The bridge deck was treated with a specialist waterproof coating. New service ducts were installed under the route of footway and the services subsequently rediverted.
Kerbs were subsequently installed and the new footways and highway constructed. The footways and highway were then surfaced with asphalt and lining was applied. The reinforced concrete parapet walls were clad in brickwork. Custom built steel parapet railings were then affixed to each corner to form complete edge protection.
Concurrently, the small culvert on Low Road was replaced as part of the same contract. The original brick culvert, dating from 1809, was replaced by a 1.2m x 1.5m precast concrete box section culvert.
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