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End of the great wait

Highways Cover story

The wait is nearly over as the A6 Great Glen bypass approaches completion, despite foot and mouth disease and flooding. Margo Cole reports.

Some of the older residents of the Leicester village of Great Glen claim they were promised a bypass way in the 1930s. Even those who moved in more recently have had a few years to wait, since a scheme to divert the A6 away from the village was given planning approval as long ago as 1992.

The project was put on hold as successive governments reviewed their roads policies, and was not revived until the current administration added it to the Targeted Programme of Improvements in 1998. But villagers can at last start planning the celebrations, as the bypass is under construction and due for completion this Christmas.

Had the road been built in the early 1980s, as originally proposed, it would have been traditionally tendered and built under a standard form of contract to a completed design. But the intervening 10 years have seen significant changes in procurement and management of road contracts, and the Highways Agency was keen to adopt a 'less aggressive' approach.

The Agency opted for a design and construct contract, transferring as much risk as possible to the contractor in exchange for the price certainty of a lump sum fixed price contract. But it was keen right from the start to engage the contractor - and the other players in the project - in a partnering style of working.

'There had been a lot of historic dialogue in the early days of this project, ' explains Highways Agency project sponsor Andrew Daws. 'We wanted to pick up where that had been left off by talking to the Environment Agency, English Nature and the key stakeholders like the statutory authorities and the County Council.

'We had this dialogue before we went out to tender and then pulled all these issues into the tender documents. Skanska has picked up where we left off.'

Skanska won the design and build contract with a £12M bid that satisfied the Agency's two stage tendering process: only after tenderers had met a minimum standard on the technical bid were price bids considered.

Dialogue - a word Daws uses frequently in the context of this project - was encouraged throughout the tender process.

Bidders held workshops with the Agency and its representative Mott MacDonald to iron out any queries before tendering, and were also encouraged to talk to other stakeholders.

'One of the things Skanska did that we really liked in the tender was to speak to the Environment Agency. They came up with a new design for the river bridge that meant they could take out a culvert further down, ' explains Daws. 'It's cheaper for them, but it also means that we end up with one structure to maintain instead of two.

'If they'd just chosen to do that and not spoken to the Environment Agency we would have been tempted to mark it down.'

As it was, this demonstration of initiative and commitment to the scheme impressed the client and helped the contractor come top in the technical bid - which also covered areas like environment, staffing and partnering, as well as design and construction.'

Skanska was restricted by the original planning consent, as both route and alignment had to stay the same. But the contractor and its designer Babtie had a free rein when to came to the detail and construction methods.

The Agency intended awarding the contract at the end of January 2001, but took longer than expected to assess the tenders.

By the time Skanska was appointed, three months later, foot and mouth disease had the nation in its grip.

Fortunately the client had already fenced off most of the site and land on the route - previously used for farming - had not had stock on it for some months. Skanska was able to demonstrate that it could implement a robust system of cleaning and disinfecting all site plant, and prove that all machinery arriving on site had been thoroughly cleaned before it got there.

For the first few months no material went off site, as earthworks subcontractor Loates completed the topsoil strip and started bulk earthworks.

All but 1km of the new 5.6km dual carriageway is being built offline to the south west of the existing A6. The vertical alignment follows existing contours, with shallow cuttings and earth bunds providing environmental protection for local residents.

Although there are five structures on the job, much of the construction effort is focused on the muck shift, which sees material from the two cuttings transferred elsewhere on the site.

'The main plan was to do as much as possible last year earthworks-wise, then finish off the structures and have a blitz on the road, ' explains Skanska's project manager Geof Garfield. 'But it was very wet around September and early October last year, which put the kibosh on the earthworks.

'We did little hits in certain areas, but didn't achieve what we had hoped for.'

As a result earthworks have continued well into this year, alongside the structures work and road construction. But even now the site can still be hit by adverse weather: last month a torrential downpour deluged the site, much of which is built on the floodplain of the River Sence.

The structures are a river bridge, three farm access overbridges and a culvert. All three farm bridges have been designed as rigid portals - integral structures with no bearing between deck and abutments, founded directly onto the hard blue boulder clay that underlies a thin top layer of weak orange clay.

Wing walls are being constructed in reinforced earth, but cannot be built until beams and deck are in place to give the structure its rigidity.

The main structure is a bridge to carry the new road over the Sence, which has been diverted during construction. Like the overbridges, the river bridge deck is constructed with precast concrete beams, but these are infilled with concrete to form the deck, while the smaller structures have a thin deck of insitu concrete formwork.

The Sence bridge is founded on bored piles that go down to the underlying Liass rock stratum. They were installed by Cementation Skanska, which used a precast concrete former through which the piles were bored. 'The former controls the position of the piles, and forms the base of the abutment. It can be used as a kicker for the next lift of the abutment, ' explains Garfield. 'It saved a lot of time.'

Employers' site representative Rod Pow of Mott MacDonald adds: 'It's also much safer.

Jack-hammering out the top of piles has never been a safe process.'

The contractor has the added incentive of a five year maintenance period. As Pow says: 'The extended maintenance period puts a lot more onus on the contractor to get it right.'

Round about

The Highways Agency is sponsoring three more schemes on the A6 south of Great Glen.

They are:

Rothwell & Desborough Bypass A 6km single carriageway bypass with climbing lanes and groundlevel roundabout junctions running from the existing A14 junction west of Rothwell to a new roundabout on the existing A6 between Desborough and Market Harborough. It passes to the west of Rothwell and Desborough and crosses two small rivers and the Midland Main Line Railway. The bypass is expected to remove 33% of through traffic from Rothwell and 55% from Desborough.

The £11.4m design and build contract was awarded to Birse Construction in February, work started in April and completion is expected in autumn 2003.

Rushden-Higham Ferrers Bypass

A £9M design and build contract was awarded to Stenoak Associated Services and designer WSP Civils last February.

Construction started at Easter on the 5.5km scheme, which will be completed in 18 months Clapham Bypass A Nuttall-Norwest Holst joint venture is building this section of the route with design by Symonds.

In 2004 the A6 is likely to be detrunked, with responsibility for maintenance reverting to the respective local authorities (Leicestershire and Northamptonshire County Councils).

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