Stoke on Trent residents know the A500 as 'the Potteries D road'. The dual carriageway has cut a grotty swathe through the city, with fumes and noise from the perpetual knots of congested traffic blighting the land flanking it. Drivers who have sped along the A50 or M6 suddenly fi nd their journeys grinding to a halt as they hit two grade junctions. These are dominated by permanently clogged roundabouts, on which movements are controlled by traffic lights.
By May next year, though, the Highways Agency is hoping to have introduced a constant, albeit heavy, flow of traffi c, and to have initiated an about turn in central Stoke's fortunes: The improvements will be followed by urban regeneration and land prices have already leapt in anticipation.
In place of the at grade junctions at City Road and Stoke Road two grade separated intersections are being built.
A500 through traffic will be allowed free flow, and wide new overbridges with generous pedestrian and cycle lane provision will allow traffic crossing the A500 smooth progress.
The scheme also involves realigning and opening up the culverted River Trent and Fowlea Brook, which crosses the A500, as well as diverting to its original Victorian alignment a short section of the Trent and Mersey Canal. Pedestrians were marginalised by the existing layout, forced into underpasses where mugging was a major risk. Along the shoulders of the road there was little to uplift anyone on foot, says David Mercer, Stoke City Council project engineer. 'By opening up Fowlea Brook we're dramatically improving the local amenity - we're also hoping to encourage birds and otters.
'In fact, whatever we do we couldn't make it worse.' Contractor Nuttall is 79 weeks (as at 21 July) into a 118 week, £40M contract, with both overbridge structures now complete. Nuttall project manager James Moloney says that though technically there are few complexities, the scheme is a logistical test.
Though all at grade, the A500's elevation swooped from sections of cutting up to the junctions, enabling Nuttall to tackle construction of the two underpass bridges top down - excavation of spoil from under the bridges is now under way as Nuttall gets stuck into the meat of a major muck shift To get to this stage, however, CFA secant piling for the abutment walls and casting of the insitu reinforced concrete decks has been carried out within the tight confines of the junction roundabouts. Plant and concrete batch trucks have had to battle through a constant merry-go-round of traffic.
At the same time as building the bridges Nuttall, with piling subcontractor Bachy Soletanche, constructed retaining walls to support new slip roads. Gaining the space needed to operate piling rigs, install rebar cages, pour concrete, and move earth has involved closing lanes, says Moloney.
Changing the elevation of the road so that it dips into the underpasses has involved planing down the sections either side of the bridges - work that is now under way following completion of the new slip roads and bridge decks.
'Traffic management has a major impact on scheme, ' confirms Highways Agency assistant project leader Jon Robinson. 'It's a narrow urban corridor, and the construction we are trying to achieve has to be done while maintaining two lanes of traffic in each direction at peak times. There was congestion before we started the project, so it would be impossible to achieve the scheme without creating more.
But we want to keep it minimal.' Moloney says that the traffic management strategy adopted has involved taking out just a single lane between the morning and evening rush hours - from 9.30-4.30. Nuttall has worked with Stoke's signalling contractor Siemens to choreograph and maximise traffic flows. He has been allowed only 120 days worth of possessions, after which Nuttall will be fined £6,400 a day for any overruns.
To squeeze the quantity of work into the time allowed him, Moloney is exploiting a feature of the original layout, which was built with an unusually wide central reservation. Nuttall has incorporated the central reservation into its works, laying new pavement and effectively creating two new lanes over which traffic can be diverted.
To allow excavation under the overbridges and construct the new, lower formation level, traffic is being temporarily routed up the slip roads and over the grade separated junctions.