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The hassle of getting ahead

Advance construction of side roads and bridges caused a major stink both above and below ground. David Hayward explains.

Kevin Cottam is well known along suburban Manchester's Hollinwood Avenue. He is on especially close terms with the newsagent, dentist and pub landlord as he spent much of 1997 being very nice to them.

For his business is disruption - or more precisely minimising it.

All around these properties, plus countless more businesses and across scores of private drives, Cottam was responsible for digging up and rerouting roads, repositioning services and discovering underground surprises like an infilled canal and a rabbit warren of old gaswork chambers full of toxic nasties.

Cottam's other day job was as project manager for a Miller/Kier joint venture contracted to build a £50M chunk of the M60 project.

Again his brief was awesome: construct 8km of new road, including 13 assorted bridges, 18 retaining walls, several interchanges and a 1km canal diversion.

But confusingly, after more than three years of construction - including 15 months' delay and an outturn bill of over £80M - the Highways Agency ended up with not a single metre of new M60.

The Miller/Kier contract was all for advance works, building the five major crossings needed to feed the motorway under busy radial routes plus a couple of railways and a canal.

The complexity of the work, even its substantial cost and time overruns, could in hindsight be claimed as proven justification for removing it from main motorway contracts and giving an early start to this large volume of side road alterations.

'Our job was more about the logistics of sequencing hundreds of traffic and services diversions than building roads or bridges, ' Cottam recalls. 'Even so, it turned out to be one of the most complex sections of highway construction either firm has ever done.'

On paper, it all looked possible to achieve in the two years allocated. New overbridges for radial road and rail routes were built using well tested sequencing.

The existing road could be temporarily diverted to allow bridge erection on the original alignment; alternatively, half the road was diverted and half a new bridge built alongside or the whole cross route was permanently realigned onto new bridges.

Only one rail crossing called for real innovation. To carve out an 80m long, three span underbridge in the 6m high rail embankment beneath the main Manchester to Oldham line, four square sheetpiled cofferdams were driven between the tracks to coincide with pier positions beneath.

With the track carried across the sheetpiling on temporary steel trestling, the cofferdams were excavated and concrete piers built within them. Finally, the trestling was replaced by permanent steel decking and the embankment between the piers dug out.

Few rail possessions were needed with only main deck erection demanding a full weekend's takeover. During these two days and nights of non stop activity, the Highways Agency ensured minimum complaints from the dozen nearby households by offering residents £60 each to take a weekend away - which most accepted.

Not so easily dealt with was the unexpected. Contaminated land was known about around an old gasworks; but not the underground spaghetti-like network of brick lined gas retort chambers, channels and sumps all brimming over with toxic hydrocarbons.

'The smell began as soon as we opened up the first hole and the foul liquid ended up seeping everywhere' says Cottam as he recalls the search for a licensed tip to accept the 200m3 of contaminants.

Also expected were the four dozen major services diversions, but not the high volume in the wrong place, including the precise alignment of a crucial section of Manchester's main water supply aqueduct from the Lake District which was found directly in the way of a new roundabout.

The side effects of such complexity were equally diverse. At one level Cottam was busy pacifying the publican for blocking his car park, or the cinema owner for flooding out a performance. At the other, he was dealing with claims and additional works bills totalling over £30M.

HA, and its consultant Mouchel, already accept at least £10M worth of additional works and £20M claims, caused mainly by the volume of contamination and services. But both sides, some two and a half years after the contract ended, are still actively debating more claims.

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