Steel Buildings in Europe

Part 1: Architect’s Guide 1 - 18 The lateral stability of the top chords of trusses is usually provided by the purlins (and by one panel of bracing, as for portal frames) but where stressed skin design is permitted, it may provide the restraint without bracing, as shown in Figure 3.10. Figure 3.10 Roof cladding acting as stressed skin in a rigid-framed truss roof 3.1.2 Pinned frame beam and column structures In a pinned frame beam and column structure, the basic configuration is a series of parallel beams, each supported by columns at its ends, with a pinned or flexible connection between the beam and the column. Bracing has to be provided in the roof to transfer horizontal forces due to wind loads to the end and side walls; the walls are braced to transfer the forces to the foundations. (Alternatively, some countries allow the roof cladding to act as a ‘stressed skin’, thus largely eliminating the need for separate bracing.) A typical structural configuration is shown in Figure 3.11. Figure 3.11 Typical structural configuration for a beam and column structure