Holdfast Training Services Trial Blog

Last week I visited 5 Broadgate which is another Mace site.  It is right by Liverpool Street Station and is prime banking territory.  UBS is having built a 700,000 sq ft building, based on a single block form, with a gun- metal grey finish. At 12 floors it will include up to four trading floors, each able to accommodate approximately 750 traders, allowing UBS to consolidate its London trading operations into one building.

So here is the problem:

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In order to overcome this issue the corner would be hung from a truss on the roof as well as Macalloy hangers on the 1st and 2nd floors. 

Here is a picture of the 3rd floor with the Macalloys in use

The (big) truss on the roof cantilevers out to allow the perimeter column to hang in tension and suspend the corner.  Jacking was used to ensure it had ‘picked up’ the perimeter.  

This system seems to have worked well on site.  It is reasonably simple to set up and control (with jacking).  Mace plan to pour all 11 floors of corner concrete at once so that there is no differential movement between the floors.  The Macalloys and roof truss will be ‘stressed’ so that any elastic extension is accounted for with pre camber.  

On the South Bank Tower we will also be using Macalloy cables, but ours will be used in the permanent design.  The proposed force in them will be 7600kN.  Anyone else got any experience with them?