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Westwood Park Link Road (A49 Goose Green)

Westwood Park Link Road (A49 Goose Green)

PROJECT DESCRIPTION

BWB is leading the design of the £16M A49 Goose Green to Westwood Park Link Road in Wigan, Greater Manchester. The scheme consists of 2.3km of dual carriageway which follows the route of a disused railway as well as an upgrade from single to dual carriageway along the existing Westwood Park internal access road. In addition a large roundabout and a complex junction reconstruction are included. Four highway bridges carrying the link road over existing road, canal and river will be provided along with retaining walls, reinforced earth slopes and footbridges. The scheme includes several departures from standard that have been approved. BWB provided highway, geotechnical, structural and environmental design services along with traffic modelling, Road Safety Audit and landscaping. The scheme was delivered using BIM Level 2 as required by the client.

BWB teamed-up with Jones Bros to develop and, where appropriate, value engineer the design at tender stage. On appointment of the contract BWB transitioned to lead designer with a proactive and collaborative approach to ensuring a technically approved design that met the clients requirements and enabled discharge of planning conditions. During the construction phase BWB remains closely involved with the project day-to-day including the formal role of Works Examiner for structures and Designers Geotechnical Advisor for earthworks elements. The project is ongoing and recently achieved 250,000 hours worked with no lost-time health and safety incidents.

Key Challenges

The project required construction of four underbridges to carry the proposed highway over an existing road, a watercourse and two canals. BWB facilitated the design process from approval in principle through to completion of the detailed design including coordination of specialist suppliers. Three of the bridges comprised prestressed concrete decks with integral bankseats placed on reinforced earthworks with controlled modulus column ground improvement below. The abutments and wing walls were built up using a modular block system which was also used for an 80m long retaining wall, while elsewhere reinforced earthworks with vegetated slopes were used.

The fourth bridge, crossing the Leeds and Liverpool Canal had a similar integral superstructure supported on steel piles which were combined with sheet pile abutment walls. In addition to the underbridges BWB delivered the design of two pedestrian and cyclist footbridges to accommodate the non-motorised user routes.

An existing masonry arch culvert which conveys flow from a lake under the existing railway embankment was affected by the proposed works. The highway alignment required the reduction of fill depth over the culvert and BWB undertook an inspection followed by assessment to confirm that it was able to accommodate the new loading. A scheme of masonry repairs was proposed to restore the culvert to a satisfactory condition and ensure the continuing performance of the asset.

Our geotechnical team were responsible for the complete HD22/08 Managing Geotechnical Risk process on this scheme. It included the provision of desk based studies, additional site investigation & interpretation, implementation, supervision and geotechnical design. The geotechnical design encompassed the assessment and analysis of earthworks including strengthened earthworks and ground improvement, drainage, pavement design including subgrade assessment and capping. The need for ground treatment including the likely mine shaft treatment in the northeast of Poolstock Bridge. A remediation strategy was produced to deal with soil and groundwater hot spots together post monitoring to ensure no contamination risks to adjacent receptors. Geotechnical monitoring and instrumentation were also designed for the construction phase with the production of an appropriate Appendix 6/12.

KEY CONTACTS

Andrew Wood

Andrew Wood
Principal Bridge Engineer
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