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70 St. Mary Axe, London

 

Project information

Location: City of London
Contractor: Mace
Sub-contractor: AJ Morrisroe & Sons Ltd
Product: recostal® 2000GTZ
Due for completion: 2018

The background

The background 70 St. Mary Axe, which also goes by the unofficial architectural moniker ‘Can of Ham’ is a new office development with a distinctive, identifiable profile, that soars elegantly from the surrounding historic streets of the City of London.

The challenge

With a base slab of 2175mm deep with five layers of 40mm rebar on the bottom, to have installed a traditional stop end and the temporary works required to support this would not have been practical or cost effective. The solution Inform UK provided on-site technical support as well as initial design drawings. 95 linear metres of recostal® 2000GTZ at a height of 1780mm was specified as the preferred shuttering to fit perfectly between top and bottom mats.

The result

The contractor saw immediate benefit to programme delivery.

A cost comparison

The following is a testimonial from the sub-contractor, AJ Morrisroe,regarding the decision to specify a permanent formwork solution rather than a traditional method.

“We compared the use of the recostal® versus the traditional method under the following criteria:
1. A temporary works design cost.
2. The cost of plywood and timber.
3. Installing strong backs, push pulls etc. and then striking.
4. Labour to install a significant temporary works stopend at a height of 2175m.
5. Carpentry to prepare and install ply combs to deal with potential leakage in the rebar layers.
6. Labour to remove the stop end in general.
7. Cost of retarder on the surface.
8. Cost of labour to treat the stop-end by scabbling or jet washing.

All of these activities became easier or unnecessary by using the recostal®. Of particular note was the quality of the Euro Code 2 joint and the absence of any need to scabble the joint and associated ‘white finger’ risks”.

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