Engineering and Construction

It is estimated that around 50% of the hot-rolled constructional steel used in the UK is fabricated into single-storey buildings, being some 40% of the total steel used in them. The remainder is light-gauge steel cold-formed into purlins, rails. cladding and accessories. Over 90% of single-storey non-domestic buildings have steel frames, demonstrating the dominance of steel construction  for this class of building.These relatively light, long-span, durable structures are simply and quickly erected, and developments in steel cladding have enabled architects to design  economical buildings of attractive appearance to suit a wide range of applications and budgets.

The traditional image was a dingy industrial shed, with a few exceptions such as aircraft hangars and exhibition halls. Changes in retailing and  the replacement of traditional heavy industry with electronics-based products have led to a demand for increased architectural interest and enhancement.

Clients expect their buildings to have the potential for easy change of layout several times during the building’s life. This is true for both  institutional investors and owner users. The primary feature is therefore flexibility of planning, which, in general terms, means as few columns as possible consistent with  economy. The ability to provide spans up to 60m, but most commonly around 30m, gives an extremely popular structural form for the supermarkets, do-it-yourself stores and the like which are now surrounding towns in the UK. The development of steel cladding in a wide variety of colours and shapes has enabled distinctive and attractive forms and house styles to be created.

Improved reliability of steel-intensive roofing systems has contributed to their acceptability in buildings used by the public and perhaps more importantly in ‘high- tech’ buildings requiring controlled environments. The structural form will vary according to span, aesthetics, integration with services, cost and suitability for the
proposed activity. A cement manufacturing building will clearly  have different requirements from a warehouse, food processing plant or computer factory.

The growth of the leisure industry has provided a challenge to  designers, and buildings vary from the straightforward requirement of cover for bowls, tennis, etc., to an exciting environment which encourages people to spend days of their holi- days indoors at water centres and similar controlled environments suitable for year round recreation.

In all instances the requirement is to provide a covering to allow a particular activity to take place; the column spacing is selected to give as much freedom of use of the space consistent with economy. The normal span range will be from 12m to  50m, but larger spans are feasible for hangars and enclosed sports stadia. Figure 1.1 shows how steel weight varies with structural form and span.

Fig. 1.1 Comparison of bare frame weights for portal and lattice structures