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THE BRIDGE IS MORE THAN 1,300M IN LENGTH

the requirement to plan, design and closure of this vital link in Scotland’s the engineering design and deliver the
construct a replacement crossing of transport infrastructure. replacement asset in time for the bridge
the River Clyde, two Scheduled Ancient The Clyde Valley was formed by glacial refurbishment work in 2019.
Monuments, a canal, a railway and the erosion, which formed a deep channel to My team of engineers and I
main dual carriageway to Loch Lomond the north side of the river. This channel commissioned a detailed geotechnical
and the west coast of Scotland. has become filled with sediments over investigation of the site, including bore
This all had to be completed in a time to form a mixed glacial till. holes in the bed of the busy shipping
three-year period with the work located Taking this into consideration, the channel. Riggall and Associates was
in an urban environment featuring a feasibility study identified two potential appointed to develop the design of
nature reserve, a five-star golf and spa routes for a replacement crossing. Both the HDD and manage the technical
resort, a public park and football pitch, a options would require a horizontal preparation of the design submission
community woodland and a significant directional drill (HDD) across the in compliance with Transport
investment in excess of £15 million. river. The first option, immediately Scotland’s requirements.
SGN revisited an earlier feasibility adjacent to the Erskine Bridge, would In early 2016, the crossing adjacent
study into refurbishing and revalidating cross below Lock 57 of the Forth and to the Erskine Bridge was identified as
the existing pipelines as well as Clyde Canal, an abandoned railway the preferred option for a replacement
identifying potential options for a line and a local nature reserve home to crossing. Transport Scotland had
replacement crossing of the river. overwintering birds. categorised this proposal as Category
The existing pipelines were installed This would involve obtaining B, requiring certification in accordance
during construction of the bridge and Scheduled Ancient Monument consent with the Design Manual for Roads
hydrostatically pressure-tested before from both Historic Environment and Bridges (DMRB) for managing
the bridge was opened to traffic. Scotland and Scottish Canals. The geotechnical risk.
Refurbishment and revalidation second option required several Installing a pipeline by directional
would have required a full closure of kilometres of 450mm pipeline to cross drilling, immediately beside such a
the bridge and complex temporary the river at a wider point and had a major piece of nationally important
works solutions to gain access to the budget cost that was three times more infrastructure, required a thoroughly
pipelines below the bridge deck. This expensive than the first. robust risk assessment at each step of
option was discounted as the road’s The project was given to me and the the design to ensure the proposals posed
authority would not permit a full SGN Major Projects team to develop no detrimental impact upon the bridge.

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12/03/2020 16:01
ErskineBridgeProject.indd 2
ErskineBridgeProject.indd 2 12/03/2020 16:01