March 2006 – The greening of sheds
Steel sector delegates at the major two-day sheds event in Newport last month (see News) heard much to please as well as much to challenge. The event was aimed mainly at developers and funders but it was also a success for the service providers. The Steel Construction Institute managed to get a copy of their new guidance for the sheds supply chain into the hands of all the 850 delegates.
We have commented frequently in NSC that sheds are getting bigger and more complex, but there were still a few surprises at Newport. Gazeley for example wants recreational facilities on the roofs of some of their 500,000m² developments. These sheds would incorporate the maximum of flexibility, with walls – even external walls – only being installed as and when required.
Our definition of what constitutes a shed may have to change. Property developer Brixton, for example, is looking at designs for sheds of up to six storeys. Others will be focussing on a new generation of smaller, edge-of-town, distribution schemes
An underlying theme of all these plans is sustainability. Carbon neutral sheds are a target of developers, funders and the ultimate inhabitants of sheds that will challenge the whole supply chain. Steel already has a cogent sustainability case and signatories to the BCSA sustainability charter may find themselves increasingly at a significant advantage as clients and planning authorities scrutinise the ‘green’ credentials of each development.
Spanish eyes are on spalling concrete
The Spanish authorities have produced their report on the causes of the fire that destroyed the Windsor building in Madrid a year ago, which has been examined and reported on in this issue of NSC (click here to see article). The report provides an excellent case study in why in forensic engineering it is dangerous to rush to conclusions before assembling and carefully reviewing all of the facts.
Although it is essentially a concrete building, much was made by sections of the UK concrete sector while the building was still smouldering of the fact that steel mullions were involved in the collapse. It is clear now that the collapse of mullions that were unprotected was not the only factor involved in the failure of the floors that collapsed.
As Dr Roger Pope points out in his NSC article, the remaining structure was condemned by the Spanish report, which has wide implications for reinstatement of fire damaged concrete structures. At the sort of temperatures seen at Madrid differential expansion caused failure of the concrete-reinforcement bond. The material ceases to be reinforced concrete and has to be condemned, and completely replaced. Everywhere the fire spread the concrete had to be condemned. So even parts of the structure that are still standing may be damaged beyond repair.
Contrast this with the limited need for replacement after fires in fire protected steel structures. Also contrast the extensive knowledge about steel in fires gained from in depth research. If the Spanish report doesn’t prompt the concrete industry into investing in research into the behaviour of concrete in fire then one wonders what will it take? Not enough is known about spalling of concrete and there seems to be little urgency to find out.