Client: West Lothian Council
Value: £1.73M
Engineer: AECOM
Completed: 2020
The project was located in Addiewell over the SSSI designated Skolie Burn which splits the town in half and is the only bus-suitable route to service one half of the town. Following an assessment by the Council, the old bridge which was half masonry arch / half 1940s concrete, had been restricted to one lane and a weight limit imposed. The project required us to first construct a temporary 33m span proprietary steel bridge (with pedestrian footpath), on reinforced earth embankments with piled foundations, as an off-line temporary diversion with associated 3-way traffic lights, and street lighting. A second temporary bridge (12m span) was installed to improve access as well as to divert services off the existing bridge (medium pressure gas, HV electric cables, BT fibre and copper cables, water main, and street lighting). The masonry arch, and concrete deck were demolished with the existing concrete abutment half retained and used in the new reinforced concrete (RC) abutment and bridge deck.
Key Issues:
• Co-ordination and implementation of various temporary service diversion works
• Being a designated SSSI we operated under a complex CAR Licence requiring close liaison / approval with SEPA / SNH
• Protection of the watercourse throughout the construction period including ‘fluming’ under the bridge
• Temporary falsework and formwork over watercourse throughout the winter
• Complex temporary works piling platform on very steep natural ground to allow installation of RC piles into rock head over existing mine workings.
Principal Elements included:
• Carriageway construction 760m2 permanent (1,100m2 temporary)
• Reinforced concrete (RC) 230m3
• RC piles (12m deep, 450mm Ø)