Millennium Bridge has been contracted in three stages.
Enabling works, being carried out by Balfour Beatty, started in November. These involve clearing sites at both ends of the bridge, including demolition of the steps leading to St Peter's Hill and excavating 3m deep holes in which the foundations will be placed. Balfour Beatty will finish next month.
Arup-Caro-Foster drew in expert advice on construction during the design phase, and selected a contractor, instead of inviting tenders. Sir Robert McAlpine and Danish firm Monberg-Thorsen have formed a joint venture to take on the job, carrying out substructure and superstructure respectively.
Under a separate contract, Mowlem Marine has demolished a jetty that stood in the river in front of what was Bankside power station - now the new Tate.
Mowlem Marine has also been placing 10,000t of limestone scour protection on north and south embankments and on the river bed where the cofferdams will be built. Demolition started at the end of January and placement of scour protection should be complete by the end of this month.
Wise says construction design 'has proved difficult, because there's no manual on the shelf'. The JV has to deliver to a tight time scale and will be under intense scrutiny.
McAlpine will begin piling in June. By July, construction of the south bank pile cap should be started and the north bank pile cap by August. The reinforced concrete piers will be cast between September and October, when McAlpine will hand over to Monberg-Thorsen.
At this point the upper parts of the piers, Y-shaped stainless steel arms, will be delivered from Monberg-Thorsen workshops and fixed. Cables will be spun across the river over a five-week period between December and January and the deck units will go on between January and March. Millennium Bridge is scheduled to open mid-May 2000.
'Because it's a real landmark in architectural, engineering and urban design terms, the quality of construction needs to be very good,' says Wise.
McAlpine/Monberg-Thorsen is aiming for the build quality normally found in marine fit-out. Pre-fabrication, mainly by Monberg-Thorsen, allows a high degree of quality control, he adds.