Steel Buildings in Europe

Part 1: Architect’s Guide 1 - 9 2.2 Minimum construction dimensions Steel enables large spans to be constructed with relatively small construction depths. The typical construction solution of an insulated external envelope supported on steel secondary members is a very well-developed solution, optimised over many years, leading to a structurally efficient and cost effective solution. For pitched roofs or short span flat roofs, the construction depth of the roof beams or rafters can be as low as 1/40 of the span between columns. If internal columns are required for multi-span structures, they may be chosen to be small members, or the internal columns may be provided on every second (or every third) frame, maximising internal space and flexibility. Steelwork supporting the external envelope may be very slender, as shown on Figure 2.2, providing the opportunity for maximum natural lighting. Figure 2.2 Slender construction takes up less space and results in transparent buildings. 2.3 Speed of construction Structural steel components are pre-fabricated off site by a steelwork contractor; any protective coating that is required is applied at this stage. The site activity is primarily an assembly operation, bolting steelwork parts together, which leads to short construction periods. The building can be made weather tight quickly, allowing the following trades early access to commence their work. Modern fabrication is achieved using numerically controlled machines, with data from three-dimensional electronic models of the complete structure. Modern fabrication is therefore extremely accurate, and errors that need rectification on site are rare. Three-dimensional building models can be used by other trades to ensure that their own contribution (for example, the cladding, or the mechanical and electrical services) can be properly co-ordinated with the structural frame before the building is constructed. All these facilities contribute to minimizing the period from conception to completion.