Engineering and Construction

In simple terms, the vertical load-carrying structure of a multi-storey building  comprises a system of vertical column elements interconnected by horizontal beam elements which support floor-element assemblies. The resistance to lateral loads is provided by diagonal bracing elements, or wall elements, introduced into the vertical rectangular panels bounded by the columns and beams to form vertical trusses, or walls.Alternatively, lateral resistance may be provided by developing a continuous or semi-continuous frame action between the beams and columns. The flexibility of connections should be taken into account in the analysis.All structures should have sufficient sway stiffness, so that the vertical loads acting with lateral displacements of the structure do not induce excessive secondary forces or moments in the members or connections.A building frame may be classed as ‘non-sway’ if the sway deformation is sufficiently small for the resulting secondary forces and moments  to be negligible. In all other cases the building frame should be classed as ‘sway- sensitive’. The stiffening effect of cladding and infill wall panels may be taken into account by using the method of partial sway bracing. The floor-element assemblies provide the resistance to lateral loads in the horizontal plane.

In summary, the components of a building structure are columns, beams, floors and bracing systems (Fig. 2.13).

1 Columns   These are generally standard, universal column, hot-rolled sections. They provide a compact, efficient section for normal building storey heights. Also, because of the section shape, they give unobstructed access for beam connections to either...

2 Beams   tructural steel floor systems consist of prefabricated standard components, and columns should be laid out on a repetitive grid which establishes a standard structural bay. For most multi-storey buildings, functional requirements will...

3 Floors   These take the form of concrete slabs of various forms of construction spanning between steel floor beams (Fig. 2.23). The types generally found are: • in situ concrete slab cast on to permanent profiled shallow or deep metal decking, acting...

4 Bracings   Three structural systems are used to resist lateral loads: continuous or wind-moment frames, reinforced concrete walls and braced-bay frames (Fig. 2.29). Combinations of these systems may also be used. Fig. 2.29 Bracing structures...

5 Connections   The most important aspect of structural steelwork for buildings is the design of the connections between individual frame components. The selection of a component should be governed not only by its capability to support the applied...

Fig. 2.13 Conventional steel frame components