Construction of Britain's first tolled motorway involves a high-profile muckshift. Judith Cruickshank reports.
Not a single wagonload of muck will leave the site of the Birmingham Northern Relief Road if everything goes according to plan. Nor will any fill or topsoil be imported. The aim is that all material moved will be re-used on the contract either as fill, for embankments and landscaping or as aggregate.
The 44km road, to relieve congestion on the overcrowded M6, will be the UK's first tolled motorway. It is being built under a ú458.5M ($672.7M) fixed price contract for client Midland Expressway by CAMBBA, a consortium of Carillion, Alfred McAlpine, Balfour Beatty and Amec. Design is by a joint Ove Arup/WS Atkins team.
Gestation of the project was long and controversial, but the contract was finally awarded in September 2000 with construction begining in April this year.
Eyebrows were raised in some circles when Caterpillar dealer Finning announced that the estimated $20.5M plant order for the contract included a fleet of eight 631E scrapers, the first new units to be sold in the UK for at least two decades.
Scrapers have never been as popular in Europe as in the US, but through the 1960s and 70s every self-respecting motorway or muckshifting contractor ran a scraper fleet. They were also popular among open-cast coal contractors for stripping overburden from the coal seams.
But as road contracts became fewer and the opencast industry dwindled, a combination of hydraulic excavator and articulated dumptruck became the preferred partnership for economic and efficient earthmoving. The advent of a brand new scraper fleet was therefore a cause for comment.
Those eyebrows were raised a inch or two further when it emerged that rather than bringing in a specialist to run the 10M. m 3muckshift, CAMBBA proposed to manage operations itself. Alfred McAlpine's heavy plant subsidiary AMPL would supply machinery as specified by the contractor and operators, and organise servicing. Management of the entire earthmoving operation would be undertaken by CAMBBA personnel.
'It was a carefully considered decision, ' says CAMBBA's John Lynch. 'There was a wide canvassing of opinion, but we eventually decided to run the operation ourselves because of its complexity. It was also felt that keeping it in-house would provide us with various opportunities and would minimise risk.'
The contract has been divided into four sections, each with its own team, which are worked concurrently. The earthworks side differs in being a single operation serving all four sections. Peter Taylor is earthworks team leader with Lynch as earthworks agent and Norman Hazell as earthworks works manager.
Weather-wise the team has been largely blessed this summer. Although earthmoving got under way around one month later than planned, the programme made up the time in just two months and is currently on schedule.
The need for flexibility has been widely demonstrated, says Lynch, and not only because, 'as the actual design comes through, the quantities change'.
The team is able to respond instantly to what is happening on the four sections. 'Section 4 ran out of granular material, so the earthworks team was contacted.
We adjusted operations so as to be able to supply them with the Class1A spec they needed. On another occasion the scrapers on Section 2 were having difficulty with ground conditions. So we sent them to another part of the contract and switched to backacter and dumptruck.'
Problems with the scrapers have been the exception though, and so far they are proving cost efficient. The eight new 631Es plus four 631Ds have been split into two teams, each controlled in the cut by a 'slasher', and hauls are averaging around 1.5km. On the whole ground conditions have been good, although in some areas it has proved worse than expected.
Haul roads are maintained by a team of Cat 14G graders. The largest excavation on the contract is at Weeford Cutting on Section 3, where some 1.4M. m 3has to be taken out.
Around two thirds of the route runs through greenfield land and ground conditions consist mainly of sand and gravel, glacial till and some Keuper marl. To add a little variety, the route also includes silt lagoons and contaminated ground in the form of unlicensed tips.
The silt lagoons are being dug out in stages using low ground pressure D6 dozers with the reclaimed material being spread and dried for re-use elsewhere on the contract.
Happily for the consortium it was able to rent a substantial area adjacent to the Weeford cutting on Section 2 from quarry operator Hanson where the crushing, screening and washing plant has been set up to prepare aggregate for re-use in concrete and pavements. Topsoil is also being screened to recover gravel. So far more than 40,000t of material has been processed and stockpiled.
Other material is being kept close to where it will be needed for landscaping or fill.
'This operation is far too complex to employ traditional contracting, ' says Lynch. Certainly, it is reasonable to surmise that the paperwork would have been massive. And the flexibility to tailor operations to circumstances might have been lost. Lynch points out: 'We are surcharging on Sections 1 and 2, and that was not in the script.' The earthmoving team has also had to work around five archaeological investigations.
Section 1, where the new road interchanges with the A460 and the M6 near Cannock, is particularly complex. Excavation has been entirely by backacters and dumptrucks with short, local, hauls.
At the other end of the route, the existing M42 has to be widened and tippers will be needed for hauls which touch on public roads, in addition to the off-road articulated dumptrucks which will use the haul roads.
Availability of the fleet has been excellent says Lynch, adding that;
'You'd have to be looking for problems in order to find one'. There is a team entirely dedicated to fuelling which operates with six bowsers and delivers constantly. Constraints on noise levels mean that the site works 7am to 7pm Monday to Friday and 8am to 1pm on Saturday.
Nonetheless work is progressing well. 'We have begun to topsoil batters and there will be some seeding this year.'
With summer drawing to a close, the earthworks team will start planning for next season. 'We've had the easy muck this year, ' says Lynch. 'At the end of the year we will know how much we've shifted and will have an accurate muck balance. Then we will reprogramme for next year', with the earthworks team doubtless offering a prayer that next summer's weather will be equally kind.
Fleet in order Machinery for earthmoving on the Birmingham Northern Relief Road is being supplied by Alfred McAlpine subsidiary, AMPL. At the height of operations it is estimated there could be as many as 200 machines at work.
AMPL placed an order with Caterpillar dealer Finning for 108 items of new plant for the contract. This included 32 articulated dumptrucks, 29 tracked excavators, 20 track type tractors - including six low ground pressure D6RLGP models, six 815F soil compactors, eight CS-563D single drum vibratory compactors and eight 631E single engined motor scrapers.
Finning also supplied six second hand Caterpillar 350 excavators. In collaboration with AMPL, Finning is providing support for the entire fleet throughout the operation.