Six firms have been invited to tender this week for the concrete core package on the 63-storey 288m Pinnacle skyscraper.
Tender documents were sent out to the six firms over the last week for the last remaining package for the tower which will become the tallest in the City of London.
Lancsville, Reddington, Stephenson, Buildstone, Byrne Bros and PC Harrington have all been invited to submit bids for the high profile job by main contractor Brookfield.
On 15 January Brookfield, formerly Multiplex, took control of the project from Mace who had overseen the demolition and groundworks for more than a year under a construction management deal.
Brookfielddecided the previous steel frame design would be strengthened with the addition of a concrete core.
Construction director Ian Pratt said: “We felt it was better to have a concrete core. It gives a much stiffer back bone to the building.”
Brookfield has agreed a guaranteed maximum price for The Pinnacle, believed to be around £575 million.
Construction is split into two phases – work up to the ground floor level, which will take another year, and then building the super-structure which is expected to be completed by 2013.
The steel subcontract will be shared in a joint venture between Dutch contractor Hollandia and Belgian firm Victor Buyck.
Gartner won the cladding, T Clarke the electrics, Schindler the lifts and MJ Lonsdale took the mechanical packages.