BUILDING SYSTEMS
Light, strong and sustainable Alternative building technologies (ABT) are becoming increasingly popular as fast and costcompetitive alternatives to conventional materials like brick and concrete. When it comes to durability and sustainability, light steel frame buildings (LSFBs) compete on an equal footing, says Mitchell Walker, director, Futurecon. By Alastair Currie
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he Eiffel Tower, erected in 1889, measures 324 m in height and is composed of hot rolled wrought iron sections. It stands today as a classic example of the endless possibilities of constructing in steel and was a front runner for a host of classic buildings. These include the 102-storey Empire State Building, completed in 1931. Like many icons of its day, its heavy-duty structural steel frame enabled skyscrapers to reach unprecedented heights. At the other end of the scale, the development of far lighter and stronger cold rolled steels over the past decades have presented a host of new opportunities for residential, commercial and industrial developments, challenging other mediums as the construction material of choice. These LSFBs can be singleor multi-storey structures, with their designs in South Africa governed by the SANS 517 building code. Formed using structural trusses and walls made from cold formed thin gauge steel sections, their internal and external walls can be clad in a range of materials, including gypsum, timber and aluminium sheeting. LSFBs are faster to construct than conventional brick-and-mortar-type buildings. Since they are significantly lighter, LSFBs also An LSFB design schematic: schools, hospitals, libraries and commercial offices are just some of the possibilities
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Before and after perspectives of a warehouse and office block development constructed using LSFB techniques
have less complex geotechnical requirements in terms of foundations. Futurecon uses 0.8 mm and 1 mm gauge steel as standard, with the option of using 1.2 mm and 1.4 mm thick sections. “Depending on the design requirements, building plans may be modular, or purpose built for each application,” says Walker. “Within the modular space, for example, we’ve recently developed a new product line under the ‘A warehouse in a box’ brand, which enables us to manufacture, replicate and supply LSFBs to customers worldwide. A warehouse building of approximately 1 200 m2 – essentially four walls and a roof – can be dispatched in a single shipping container.” Within the industrial market, recent completed projects include a 2 000 m2 warehouse with 1 000 m2 office block development for a client in Johannesburg. Meanwhile, in Cape Town, Futurecon is currently working on a renovation project, where the scope of works entails the supply of a 2 000 m2 roof plus 1 300 m2 of wall cladding for an existing building.
Unsupported spans Within the commercial and industrial space, LSFBs compete favourably with steel portal frame structures, typically composed of more robust horizontal beams or trusses that will need some measure of piling. Portal frames are designed with interspersed vertical I-beam columns to support the roof span. Being lighter, the roof load bearing capacity of LSFB systems allows for impressive unsupported spans of up to 48 m. Roofs can be assembled in complete sections on the ground and then lifted and positioned by crane. As a further plus, external walls are around 130 mm thick compared to up to 240 mm for brick. Additionally, since the bulk of the components is delivered in sections from the factory, there’s minimal – if any – wastage on-site, which translates into further cost savings. “In all respect, the foundations need to be perfectly level to the last millimetre to achieve flat walls with exact 90-degree corners,” says Walker. As an integrated system, LSFBs provide exceptional thermal efficiency, with Futurecon’s standard walls achieving R values
