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| Steel reinforcement innovation  The rapid construction of one of the largest concrete frame structures in the UK was aided by the use of Bamtec, an off-site fabricated steel carpet of floor slab reinforcement. Construction of the Forth Valley Royal Hospital involved the collaboration of many contractors and the application of innovative approaches to the construction. Bamtec, manufactured exclusively by Hy-Ten in the UK, contributed to the on-time completion of the frame and reduced the carbon footprint of the project. Buildings of such sophistication require an extended period for finishing and fit-out and so the construction programme had a tight window for the completion of the structural frame. Hy-Ten were approached to see if the application of the Bamtec system could speed site placement of reinforcing steel in the floor slabs and so hasten completion.The Bamtec system uses finite element analysis to determine the stress loading within the floor slab. From this analysis, the precise diameter, length and spacing of reinforcement required in each zone is specified to achieve the engineer's exact needs. Manufacturing data is ported directly to robot welding machines that position and spot weld each re-bar onto steel tapes to create a bespoke carpet with each bar precisely located. These reinforcement carpets are then rolled out on-site to create the required steel reinforcement mat. Using Bamtec reduced the reinforcement required at the Forth Valley Hospital by around 190 tonnes. In addition to the material and labour cost saving, around two tonnes of carbon dioxide are saved for each ton of steel eliminated. Additional carbon savings arose from lesser transportation demands to carry material to site. Overall, the carbon footprint of the construction was significantly reduced. On many projects, contractors using Bamtec have been able to save up to one week per floor in build time. This was certainly the case at Forth Valley, where the teams were able to place the steel reinforcement, to a complex floor plan, far more rapidly than with conventional manual bar placement. "Around 1000 tonnes of steel was used in this project. During the most intensive phase, one truck per day left the Bootle factory with 28 tonnes of engineered reinforcement," explained Hy-Ten director Richard Webster. Few installations are straightforward and Hy-Ten has gained vast experience in resolving site problems. Precast columns were opted for to benefit the programme, rather than using conventional in-situ cast columns. Re-bars cast into the columns were bent at 90 degrees at the top of each column to lock into the floor slab. This created potential problems with the laying of the rebar carpets over the columns. Hy-Ten overcame this problem with the use of fabricated ramps. These allowed the carpets to be fully rolled out over the protruding column steel work. Once the carpet was placed, the mat around the columns could be easily completed with the addition of a small number of loose bars. The new hospital, commissioned by Forth Valley NHS, will serve a population of 300,000 and will be supported by a network of community hospitals in Stirling, Falkirk, Bo'ness and Clackmannanshire. The hospital opens in three main phases and, when fully operation in July 2011, will provide 860 in-patient beds as well as A&E, out-patient, day surgery, diagnostic and therapy services. write your comments about the article :: © 2011 Construction News :: home page |