The future tallest building in the City of London, Heron Tower, now has its steel structure rapidly shooting up.
So far construction has seen the steel work for the double height ground floor and lobby area erected along with four floors above it putting the building at a around 10% of its total height.
The steel is fabricated off site, with a maximum tolerance of +/- 1mm and then transported to 110 Bishopsgate where it is put together, a bit like a giant piece of mecano with parts stretching as much as ten metres long but having to fit perfectly together.
At the rate of two floors every two weeks, the contractors start each level of steelwork on the eastern side of the building and then work round it until they end up at the north-west corner.
Already visible is the bracing of the building that works as an exoskeleton to keep it standing in lieu of a central concrete core allowing the floorplates to be much more open than a central core would permit.
One of the emergency stairwells on the side of the tower is starting to take form now and will eventually reach all the way up the side offering a challenge for anyone who feels fit enough to run up it. This will be a blast-protected area to offer additional safety against disaster and terrorist attack.
Meanwhile the climbing frame has been attached to one crane. This will permit the crane to be jacked up in height as the structure rises further allowing it to keep pace with construction.
Assuming the wind speeds permit work to continue as the cranes get higher and higher and they don't have to stop thanks to gales, main contractor Skanska should have Heron Tower almost topped out by the end of 2009.
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