Hailed as a UK first, Manchester Airport's multi-modal transport exchange is taking shape. Dave Parker reports.
Manchester International airport managers may nurse plans for a massive expansion in passenger traffic over the next decade and a half, but their dreams are tempered by one particularly harsh reality. Space around the three modern terminals is extremely limited. Unless the terminals are to be ringed by endless ranks of multi-storey carparks, more and more passengers and staff must be encouraged to use public transport.
There is also a parallel demand for on-site office space to match the new passenger levels. Manchester Airport senior development manager Aslam Khan says all these needs will be met by the new £60M Ground Transport Interchange (GTI) project, now well advanced towards its May 2003 completion date.
He explains: 'We chose the existing rail station as the anchor of the scheme, and planned to add a new bus and coach station and provide facilities for a Metrolink light rail connection. The idea is to provide seamless integration of all modes of transport, eventually including check-in and baggage handling facilities which will relieve pressures in the terminals.'
Already linking the terminals was the elevated Skyway, a glazed tube containing travelators as well as walkways. 'Originally it was planned to squeeze the GTI in off to the side of the Skyway to ensure there was no disruption to passengers during construction, ' says John Rossiter, manager for civil and structural engineer Mott MacDonald. 'But from the design point of view it's obviously much better for the Skyway to radiate from the hub, so minimising disruption became a construction rather than a design priority.'
Main contractor Skanska's project director Reg Tranter agrees that keeping the Skyway in operation - and maintained to its original standard - was one of the biggest challenges his team faced. 'It runs right through a major building site, ' he points out. 'There were times when we were handling large steel trusses right alongside and above it, so public safety was always an over-riding priority.'
In fact the almost completed £22.5M shell and core contract suffered from an unusual combination of restrictions. In terms of access and space it resembled a typical congested city centre project. Then, much of the work had to be conducted alongside or over a live railway line, with all the inevitable complications of possessions and safety precautions. Working in the middle of a busy international airport, however, has special restrictions.
'Low cloud was worse than high wind, ' Tranter reports.
'Once the ceiling was below 250m or visibility less than 3,500m our crane jibs had to come down. Weather and wind delays have been bad enough without low cloud as well.'
Ground conditions under the former staff carpark site were 'fairly good', he adds. A grand total of 777 CFA piles, 600mm diameter and up to 11m deep, were installed, including 153 beneath the new tunnel under the site which has been constructed in anticipation of Metrolink's arrival in 2005.
New construction above ground level divides into two complementary sections. What all passengers will experience is the central 1,200m 2Hub concourse, a two storey high atrium featuring dramatic tubular steel trusses fabricated by Watson Steel. Supporting the Skylink level are massive 35m long by 3.15m deep members made up of circular hollow sections up to 406mm in diameter. These create an unobstructed floor space where in due course check-in desks and baggage-handling facilities will be installed.
Departing passengers will enter the Hub from all forms of public transport, then move up to the Skylink to access the appropriate terminal.
Alongside the Hub is a new coach station topped with a six storey office block offering 8,100m 2of lettable space. Construction here is relatively conventional, says Rossiter, with a steel frame on a 6m grid and composite Slimdek floors.
Cladding is 'pre-patinated copper look-alike, with distinctive blue glazing'.
Manchester Airport station already features eye-catching architecture, in particular at roof level. The new Hub will be equally dramatic, with a curving canopy supported on yet more tubular trusses. Tranter has mixed feelings about the roof itself.
'The Kalzip aluminium roof sheets used were 28m long. They had to come in on 35m long trailers, and only on Sundays. By comparison the roof trusses, which weighed up to 18t, were much simpler to handle.'
By 2015 Manchester Airport plans to overtake London Gatwick to become the UK's second busiest airport. This means 41M passengers a year compared to the current 19M, a daunting target requiring major investment if it is to be met. Two key improvements have already been completed - new terminals and the controversial £172M second runway, which opened last year. The third, crucial component is improved access to the airport, where terminals and carparks are tightly corseted by urban development and Manchester's green belt.
Better public transport is the answer: 12% of passengers arrive by public transport. The aim is to get this up to 25% by 2005 - which should be around 6M a year.
By then light rail, in the form of an extension to Manchester's successful Metrolink network, should have arrived at the existing heavy rail terminus in the centre of the terminal area. Here the platforms are already being extended to take trains of up to 10 cars and a new platform is under construction. Land has been set aside for construction of more platforms.
Extending the heavy rail line westward to link up with the West Coast Main Line is being considered.
Another priority is to persuade more of the airport staff to use public transport.
Some staff parking has already disappeared beneath the new interchange (see main story), but with staff numbers predicted to rise in line with passenger numbers - to 35,000 by 2015 - pressure on the limited car parking area would otherwise become acute.
Although money has already been invested in improving local bus and coach services to the airport, the real key is Metrolink, which will eventually connect the central area directly with most of the residential areas of Manchester.
Client: Manchester Airport plc
Civil and structural engineer: Mott MacDonald
Architect: Aedas AHR
Building services engineer: Hoare Lea & Partners
Quantity Surveyors: Citex
Contractor: Skanska Construction
UK Contractor's architect: Jefferson Sheard
Contractor's civil and structural engineer: Scott Wilson
Kirkpatrick Contractors building services engineer: Silcock Dawson & Partners