When UK prime minister Tony Blair decided that London needed another tier of government and a city mayor, the next step was to spend £50m ($70m) building a home for the new city authority.
London now has its mayor, Ken Livingstone – a once notorious radical politician – and by spring 2002 it will have a spectacular new headquarters for the Greater London Authority. The 42m-high building, on the south bank of the river Thames just near Tower Bridge, is a distinctive ellipsoidal shape, like an egg toppling over.
The glass-clad building was designed by Sir Norman Foster’s architectural practice, and was engineered by Arup.
All three tower cranes on the project, together with operators, have been supplied by Select Tower Cranes, the UK dealer for Terex Comedil, to construction manager Mace. The cranes are:
• a flat-top Comedil CTT 561, with an 80.3m height under hook and a 70m jib. At jib end it lifts 6.3t. (This crane is capable of a freestanding height of 104m, and Select has 11 of these in its fleet.)
• a Comedil CT 703, with a 57.7m height under hook and a 65m jib. At jib end it lifts 4.t.
• and a Comedil CT 651, with a 52m height under hook and a 30m jib. This crane lifts 6t at full reach.
The towers were installed on site in mid 2000 and are scheduled to come down before the end of this year.
While the lifting on the project is relatively straightforward, the structural engineering is quite complex, because of the shape of the building. The angle of the exterior wall to the ground is as sharp as 22% in some parts. The large lateral loads are transmitted to 10 steel columns, each 600mm in diameter, and a reinforced concrete box core cantilevered from nine floors. I-section floor beams anchor the primary columns to the core.
