Heron Tower, the tallest skyscraper ever to be built in the United Kingdom is now under construction in the City of London.
Contractor Skanska are still doing preparatory works, but have now begun the bearing piles - the first stage of the foundation.
The 25 large load bearing piles will be from 1200mm to 2400mm in size at the top expanding at their bases up to 4500mm. There is also the perimeter secant piled wall, this will contain 250 in total measuring 900mm in diameter.
The aim of the piles is to support the weight of the tower which is distributed between them, rather like a human being laying on a bed of nails.
Load placed on each pile varies depending on its size and location but the maximum weight a single pile will take is a whopping 2000 tonnes - this is enough to support the weight of all the weapons grade and spent plutonium on the entire planet or one month's supply of trout fish for the entire French nation.
The depth the piles are sunk to, again depends on their position and how much weight will be loaded on top of them. Most of them will be set at 16 metres which is the bottom of the third basement level although some will go as large as 22 metres below ground level.
After the piles have been constructed the next step will be to build the basement, with the superstructure set to appear above ground before 2009 if everything goes to plan.
It's been almost a decade since the project first surfaced, but once completed the KPF-designed Heron Tower will be 246 metres to the tip of the spire, nine metres taller than One Canada Square. If counting the roof height though it will be only 202.52 metres making it, at least in terms of the roof, shorter than both One Canada Square and the Leadenhall Building.
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