• Approved


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  • Manufacture
  • Design


  • Metframe Light Gauge Steel Frame Building System

Description of Metframe Light Gauge Steel Frame Building System

The open panel system is manufactured offsite and erected at site. They provide internal and external load bearing walls along with floor and roof panels.

The basic principle of Metframe superstructures is that lightweight galvanised steel sections are used to form the structural elements of a building, based on proven engineering methods. Each storey height of the building frame is tied together and at each floor level with the floor construction which demonstrate adequate robustness as indicated in BS EN 1991 1 – 7 and UK National Annex to BS EN 1991 1 – 7.

The Metframe panel consists of vertical and horizontal steel channels; bolted together using countersunk bolts to form a frame. All sections are cold rolled from pre – galvanised steel strip to BS EN 10346; grade S450GD which has a minimum
yield of 450 N/mm².

Externally, panels are fitted in the factory with an A1 non-combustible sheathing board and potentially insulation dependent on the external wall finish. On site the panels are fitted together using bolts, lined, and plumbed, before the plasterboard is added. Internal panels are fitted on site with two layers of board to both wall faces to suit the fire protection requirements. Where openings are required in the panels, these are accommodated as required with any additional lintels being incorporated. Cold – formed steel joists are designed to support the roof construction and these loads are taken to the supporting load bearing wall sections. Horizontal forces into the roof are typically transferred into the shear wall through the use of the roof lining material acting as a diaphragm. Where this is not possible an additional roof plan girder is provided to transfer loads to cross walls. Floors are constructed from single span composite concrete floor slabs supported by zed ledger angles. The slab sits on to the bottom horizontal leg of the zed member, and the top leg sits on to the top of the Metframe panel. All zed members are bolted to the face of the panels. On long span floors, temporary propping would be required during the construction phase. These concrete floor slabs are supported by the load bearing walls, again resisting the cumulative axial loads down to foundation level. Overall stability of the structure below the roof level is dependent on the floor construction transferring horizontal loads to the shear walls. Stability to these shear walls is typically provided by the use of flat strap cross bracing to panels internal and externally. These straps are typically 1.2mm gauge 90mm wide strips fixed at the head and base of panels at stud node positions. Horizontal loads are transferred vertically down through the building through these braced wall systems to the supporting structure by others. The layout of these cross bracing straps are set out to limit any potential uplift effects at the lowest floor.

Durability Assessment: minimum 60 years

Limits on scope

  • Maximum 15 storeys for loadbearing frames subject to structural analysis (with the incorporation of hot-rolled steelwork to achieve structural design parameters)
  • Bottom members in contact with foundations/sub-structure must be fully isolated from contact with moisture from the ground or external sources
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  • Where lightweight gauge steel framing is used for ground floor construction, the ground below the floor must be sealed to prevent moisture entering the void, such as a membrane with 50mm oversite concrete, in accordance with the recommendations of Steel Construction Institute publication P262.
  • Where a lightweight gauge steel frame ground floor occurs over a void next to the ground, the void must be cross ventilated to a minimum standard of 1500mm2/linear metre, or 500mm2/m2 of floor area.
  • Masonry wall cladding cavities should be minimum 50mm and ventilated.
  • Conventional cladding, such as timber cladding, should have a minimum 25mm drained back-cavity, or as recommended by the manufacturer.
  • Rendered external thermal insulation systems and/or insulated brick slip cladding systems applied to steel-framed structures must have a minimum 25mm drained back-cavity.
  • Stainless steel fixings, such as channels for masonry retention systems, must be isolated from the galvanised steel to prevent bi-metallic corrosion where there is a risk of exposure to moisture.
  • Metframe must be contracted for the design, manufacture and supply of the structures.
  • The structural analysis and design for the structure is undertaken by voestalpine Metsec plc’s in-house Engineers.
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