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Sharing the spoils

A major road widening project is sharing space with the UK's new rail link to the Channel Tunnel

Partnering isn't easy; we have to put in a lot of effort, ' says Colin Chadwick, the UK Highways Agency's project manager for the A2/M2 widening.

The ú125M ($190M) design and build project is seen by the Agency as a shop window for partnering, and no effort is being spared in ensuring its success.

Nightly workshops are held on site to spread the philosophy, from senior managers down to subcontractors. All staff who attend the workshops have to sign an agreement to be honest, open and co-operative, and to avoid creating a blame culture.

In fact, the site office has been designed to promote partnering. All four members of the M2 Alliance - the Highways Agency, Maunsell, WS Atkins and contractor CSM (a Costain/Skanska/Mowlem joint venture) - are housed in a long narrow office, with staff grouped by job type rather than affiliation. Most of the staff have only been on site for about two months and are still finding their feet; few have had experience of partnering between so many parties.

The project has been a long time coming: 11 years were spent in preliminary planning while the hybrid Channel Tunnel Rail Link Bill - which incorporated the A2/M2 widening - passed through both houses and two parliamentary select committees.

During that period Maunsell developed an illustrative design for the road widening project. Once the bill had been passed, the pace of planning increased dramatically to ensure the road scheme could be built at the same time as the CTRL, which is in the same corridor.

There was a year from pre-qualification to tender, with CSM appointed in November 1999. 'The biggest problem has been to mobilise a big enough design team, ' says Steve Cardwell, design manager for WS Atkins, which is carrying out the detailed design for CSM. Two months into the earthworks on site, and with the detailed design only 50% complete, partnering is seen by the alliance as the only way to get things done.

The job is complex. Parallel widening of a 17km length of the A2/M2 between Cobham Junction and Gillingham requires the complete reconstruction of two motorway junctions and 11 overbridges as well as the construction of a new bridge over the River Medway and strengthening of the existing structure.

The new four lane London-bound carriageway will be built first with traffic then diverted on to it to allow reconstruction of the existing dual carriageway.

The site runs parallel to the CTRL works for 10km, and at the Medway crossing is only separated by 20m. This has resulted in some mutually beneficial arrangements. The CTRL contractors and CSM share access and haul roads, collaborate over survey data and traffic control, have exchanged materials and land, and the CTRL contractors have had input into the design and construction of junctions. Colin Chadwick says: 'We are in bed with CTRL.'

Planning the new Medway road bridge required close collaboration to ensure the design was sympathetic to the existing M2 bridge and the adjacent CTRL bridge, which is currently being built.

'We had to get the same vertical alignment, and wanted to avoid a forest of legs, ' explains Chadwick. Virtual reality models were developed to analyse the arrangement of the three parallel bridges from all possible viewpoints.

Perhaps the most significant result of the co-operation between the two adjacent sites is the use of 250,000m 3of chalk spoil from the CTRL as embankment fill.

Spoil from the North Downs tunnel is being placed to form an embankment directly adjacent to the northern tunnel portal. Overall the re-use of material will save 20,000 vehicle movements on local roads. 'It's a win-win situation, ' says Chadwick. 'CTRL avoids tipping and we get good material.'

Chadwick concedes there are some cultural differences between the two parties. 'They are commercial and want to build the CTRL at least cost, ' he says. 'We have a broader duty of care.'

The M2 Alliance is paying CTRL for the fill, and according to Chadwick 'they play hardball'.

Construction of the Medway bridge and junctions 2 and 3 are seen by the Alliance as the most technically challenging aspects of the work.

Of these, junction 3 reconstruction is the most complex, as it involves extensive service diversions and a complex traffic management strategy with 14 different phases.

The existing Medway bridge will be strengthened by placing new cambered deck sections over the old deck.

The M2 borders an area of outstanding natural beauty. As a result, there has been extensive replanting of hazel and sweet chestnut, and ú1.5M was spent translocating soils from an ancient woodland, the largest operation of this kind ever undertaken in the UK.

Relocation of dormice and slow worms has required hands and knees searching; site roads have been realigned to avoid badger sets; and badger fencing has been placed around the site.

Good community relations are vital on a job of this scale.

A scout camp at Buckmore Park is to be demo l ished and rep laced by a new purpose built facility: and concerns from local residents have resulted in engineers avoiding the use of driven piles on the new Medway bridge.

If everything goes to plan the works are due to be completed at the end of 2002.

Materials world

The works involve the largest use of secondary materials on a road project in the UK.

Recycled concrete will be sourced from the demolished structures on site and the surrounding area, and combined with recycled pavement material to form 50,000m 3of capping, avoiding the need to import rock from local quarries.

A new performance specification is being developed for this capping material by Scott Wilson Pavement Engineering.

The new build London-bound carriageway will use lime, ground granulated blast furnace slag and cement- bound materials to stabilise the chalk sub-grade, to avoid importing capping and crushed rock sub-base.

Pavement design has yet to be finalised, but is expected to use quiet asphalt surfacing.

On the spot

Name: Ron Martin

Job: Maunsell employer's site representative A2/M2 widening

Qualifications: CEng, MICE, MIHT

Age: Older than 58

Best thing about the job: Partnering

Worst thing about the job: Expect it will be traffic control

Highlight of career: RE with Kent CC on Wainscott Bypass - it was nice to see the whole project through from start to finish

Advice to young engineers: Grab every opportunity on site and in design; be flexible; don't always work by the book

Anything else: Only gave up playing field hockey last year

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