However, steel is not only a material with a high mechanical potential, but it also offers countless advantages in the choice of casing, thermal-acoustic insulation and sustainable construction.
These properties have made steel the preferred choice of architects, especially in the construction of multi-storey buildings.
These are two different functional areas that have to respond to similar demands on the use of space and consequently employ similar structural typologies.
The primary need is to cover large spaces without intermediate pillars with covers at heights generally higher than those of the residential construction floors.
Large spans are the field of use where materials with high strength, such as steel, can be optimally exploited, often through the adoption of reticular systems.
But it’s not just a question of feasibility. Other aspects also play a fundamental role in the world of production and exhibitions: speed of execution, modularity and the possibility of expansion, the possibility of relocation.
If the question of seismic performance is analysed on the basis of the three fundamental parameters: mass – own period – ductility, the properties of metal structures are unquestionable.
Structures that belong to construction systems that usually have vertical closures and roofs made of lightweight prefabricated sheet metal panels with internal insulation layers, so the consideration of lightness extends to the construction as a whole. As far as design choices are concerned, it is easy to find oneself faced with inverted priorities with respect to multi-storey buildings.
The masses are so small that the seismic action becomes secondary to the horizontal action due to the wind, proportional to the width of the surfaces.
The advantages of adopting a steel construction for these structural types are emphasized in seismic zones.
The IPE and HE profiles used for the beams and columns of multi-storey buildings are generally available at distribution centres within a short time frame. Riberi P. Costruzioni is capable of cutting, punching, drilling, oxyfuelling, carving, cold sawing, applying a counter-bar, straightening, bending, calendering, welding and attaching connectors to frames and profiles.
All prefabricated elements can be sandblasted and subsequently painted or hot-dip galvanized before assembly.
Tubular profiles (circular, square, rectangular) are becoming more and more widely used as structural elements, given the pleasant visual impact that this type of profile offers to the project. Tubular profiles can be hot rolled and hot formed. Support tubulars can also be welded, hot rolled and cold formed tubes obtained following a process of shaping flat rolled products and subsequent welding (longitudinal or helical), in accordance with the UNI EN 10219 standard. Tubular profiles for structures must be in compliance with the regulations.
Composite beams are profiles with a double T laminated shape and subsequently cut and reassembled: they are mainly used in roof structures, floors and similar features in general. The particular conformation of the composite beams allows a higher performance compared to traditional beams, allowing to reach important spans.
Both simple elements (with constant height cross section) and elements with special features can be used: variable height, curved and/or with pre-welded connectors on the upper flange.
The integrated beams in floor thickness, are a new concept of metal carpentry structure: floors with the presence of totally or partially prefabricated elements (trapezoidal sheet metal or pre-compressed honeycomb elements) combined with IPE – HEA beams with subsequent completion casting.
This system offers considerable technical and economic advantages: use of prefabricated elements, lightening of the construction, simplicity of execution, lower costs, greater fire protection.
The most common solution is the trapezoidal sheet metal floor with overhanging concrete casting. These corrugated sheets (minimum thickness 0,8 mm) are characterised by the presence of “notches” on the vertical element of the trapezoidal element to anchor with the concrete. They ensure high structural performance, low overall thickness and site productivity. The corrugated sheets can also be used as a simple disposable formwork.
The corrugated sheets can also be used for “dry” attics for the benefit of greater industrialization of the site.
The glass “double skin” allows, through thermoregulated mechanisms, to exploit the natural and mechanical ventilation: maximizing the energy supply in winter and lightening the consumption in summer. In this way, internal thermal loads are limited and energy consumption is reduced.
The support and tie rods of the glass facade can be made with square or IPE -HEA bars, with other merchant laminates, with specially shaped bars and/or with cold bent profiles.
Within the building shell, the variety of sheets on the market allows a wide choice of galvanized, aluminized, painted, stainless steel, corten, etc.; grids can also be used. The sheets are also part of pre-insulated prefabricated panels. They contribute to the various architectural solutions such as curtain walls, interior sound absorbing panels, sunshading elements, etc. In particular, “perforated sheet metal” is a product with high potential of use for external cladding. Particular micro-perforated sheets are available on the market, which allow, depending on their arrangement with respect to the sun, to passively protect the building, creating a shading and a shading effect that favours the creation of a naturally balanced internal microclimate.
They are products of industry for the industrialization of the construction site. Properties: light weight, low thickness for greater usable space, thermo-acoustic insulation, quick assembly, curtain wall surfaces (with “hidden” joint), chromatism for the wide range of colours of the pre-painted galvanized steel or pre-painted stainless steel facing, durability.
Elements with ‘t’ thicknesses between 0,5 and 3,0 mm, hot-formed products (merchant bars), small angles (‘L’), ‘T’, ‘U’, special profiles (e.g. ‘Z’ profiles, ‘T’ profiles with unequal wings, etc.) and/or thin profiles (cold-formed) have the task of holding the sheets for the infill, cladding and/or covering panels.
They are prefabricated panels with double facing and in pre-painted galvanized steel, stainless steel or aluminium, with insulating material in between. Wide typological range, thermal (and also acoustic) reduction, mechanical resistance and lightness, easy installation, durability. Advantages also in fire safety both in terms of reaction to fire (with polyurethane or polystyrene insulation) and fire resistance (with mineral wool insulation). Increasing use in the reclamation of obsolete and outlawed asbestos cement slab roofs. Also available in flat and curved panels, as well as for photovoltaics.
The connections of the structures can be made by welded joints (made on site or in the workshop) or bolted joint