a
b
Steel frame systems
mantling, the choice of the correct connection technique is important.
Steel frames have been used as a constructional principle for a wide variety of building forms ever since the development of modern steel construction. Columns and beams made of steel sections create a frame of linear members with minimal weight that has high load-bearing capacity and allows large spans between the columns. This means that very long spans are possible with few constructional elements, but the most economical spans are between 6 and 18 m [2]. The international standard unit for dimensioning steel construction elements is the millimetre. During the design work the spacing between columns and beams is determined by means a structural grid. The widespread use of computers today enables designers to abandon orthogonal grids and allows frames of almost any conceivable form to be created (fig. C 2.2). In frame building systems, loads are transferred to the foundations via beams and columns. Bracing elements ensure the stability of the construction horizontally and vertically. The elements that make up the structural system can be rolled steel sections, hollow steel sections or composite elements. Horizontal bracing is provided by the floor slabs or horizontal girders, and the steel structure can be braced vertically by rigid corner joints, girders or solid wall plates (figs. C 2.3 and 2.4). In a frame construction system all loadbearing elements are prefabricated and then transported to the construction site. Using the appropriate plant the building elements can be lifted directly from the transport vehicle to the point in the building where they are required. To ensure simple and efficient assembly and dis-
C 2.2
Construction elements
The process for manufacturing semi-finished building elements out of steel combines the processes of manufacturing primary forms with hot- or cold-forming techniques. The primary shaping process is either one of ingot or continuous casting to achieve the primary form, which is
C 2.3
then refined by hot- or cold-rolling techniques to create various semi-finished elements. Semi-finished elements of cast iron and cast steel are manufactured in a single production step in which the molten raw material is cast into moulds (fig. C 2.6, p. 56). Steel sections Sectional steel elements are semi-finished elements used as columns and beams in steel construction.
C 2.4
55