News

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NEWS Wolseley Spanish condemn Madrid fire concrete expands in Spanish authorities have produced that it is likely that the upper storeys and progressive load shedding. But Leamington fire in Madrid a year ago, condemn- protection been in place. BCSA Tech- heat from the fire which started at thedid it? My analysis suggests that thewould not have collapsed had firetheir report on the Windsor Building ing the surviving elements of the con- nical Consultant Dr Roger Pope said: northern end reduced the capacity of crete structure as beyond repair. The ”The report concludes, unsurprising- the columns critically, so they were report scotches earlier suggestions ly, that if you do not protect light steel unable to withstand the load from that failure of unprotected perimeter members they will fail in a prolonged weakened mullions together with steel mullion columns was the sole fire. Most levels below the 17th were whole frame expansion effects.” cause of the building’s collapse (see protected, but on the 9th level which The report also says that every- article on p26). was unprotected the mullions buck- where the fire spread the concrete During the fire the top ten storeys led but did not collapse as the loads was then condemned, because dif- at one end collapsed and much of were taken by alternative load paths, ferential expansion causes failure of the perimeter above the 17th storey which is a classic robustness provi- the bond between reinforcement and collapsed later. The building was sion.” concrete in fires in excess of 500°C. constructed using a concrete core, Dr Pope says that alternative load In the Madrid fire this temperature internal concrete columns, RC waffle paths above floor 17 failed to prevent was reached to a depth of 100mm slab floors and steel perimeter mul- collapse because there was no ef- over more than half the floors and lion columns. The mullions had origi- fective fire compartmentation, and columns. nally been left unprotected and were because of failure of two portalised Dr Pope said:“This means that being gradually protected during a internal 1200x500 concrete columns reinstatement would be impractical refurbishment programme when the at the northern end of the building because so much of the structure, fire struck. which collapsed. “The report con- having been exposed to this None of the fire protected mullions cludes that the failure of these col- severity of fire for so long, would be failed and the Spanish report says umns resulted from debris loading condemnded.” Atlas Ward Structures is erect- Heathrow tower Once the structure was erected, the next for a new distribution centre in under control cables that would be tensioned from thechallenge was to install six steel macaloid ing 1,700t of structural steelwork Leamington Spa for construction top of the tower to keep the slender struc- products and materials distributor An 87m pre-fabricated steel control tower ture stable in high winds. Wolseley UK. at Heathrow Airport has been completed A curved piece of steel was fitted onto The new building will provide ahead of schedule after the structure was the corners of the three storey base building 35,000 m2 of floor space and it is jacked up within a live airport environment. for each of the six steel cables to rest on while situated adjacent to Wolseley’s Under the £50M project, the 1,000t cabin of the they were tensioned up. Headquarters at Spa Park. Lead by control tower was pre-fabricated by Bolton-based Peter Czwartos, Project Manager at main contractor FKI Logistex and Watson Steel some three kilometres away from the Mace, said the key to success was detailed plan- subcontractor Bowmer & Kirk- tower’s location next to Terminal 3. The completed ning among an integrated team including cron- land, the development comprises 27m high cabin was then rested onto a 200t lift- tractor Mace, structural engineer Arup and steel- two buildings, 61m apart, that are ing yoke, place onto three trailers and rolled two work contractor Watson Steel. connected by a link bridge. This miles along the runway in a painstaking night-time “There were a number of technical chal- ensured optimal use of the site operation. lenges that would be difficult enough in their own while allowing vehicle access be- Temporary strand jacks from three lifting tow- right without such challenging site conditions,” he tween the buildings. Each building ers were then attached to the cabin which was said. “But to do it in such a confined space in a live is constructed with triple spans of hydraulically lifted. As the cabin rose, eight sec- airport environment was a major logistical chal- 30m and is 15m high to eaves. tions of the slender triangular shaped steel mast lenge. Everything had to be 100 per cent planned. A small difference in total were slotted in underneath. There was no scope to improvise.” height between the two buildings meant that the fully enclosed link bridge had to be designed and constructed to a slight gradient. The 9m wide bridge has a clear centre span of 32m, is 6m off of the ground and links up with mez- zanine floors in both of the build- ings. It is designed to enable pallet trucks to move easily between the two buildings. The building should be fully op- erational by the end of 2006 and will employ more than 150. 6 NSC March 2006


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