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Steel Designers' Manual - 6th Edition (2003)
44 Multi-storey buildings
lighter and stronger materials. This has generated a greater need to consider
serviceability, including dynamic floor response, as part of the development of the
structural concept.
Other important considerations are to ensure adequate resistance to fire and
corrosion. The design should aim to minimize the cost, requirements and intrusion
of the protection systems on the efficiency of the overall building.
Architectural aims
For the vast majority of buildings the most effective structural steel frame is the one
which is least obtrusive. In this way it imposes least constraint on internal planning,
and produces maximum usable floor area, particularly for open-plan offices. It also
provides minimal obstruction to the routeing of building services. This is an important
consideration, particularly since building services are becoming more extensive
and demanding on space and hence on the building framework.
Occasionally the structure is an essential feature of the architectural expression
of the building. Under these circumstances the frame must achieve, among other
aims, a balance between internal planning efficiency and an expressed structural
form. However, these buildings are special, not appropriate to this manual, and will
not be considered in more detail, except to give a number of references.
Financial aims
The design of a steel frame should aim to achieve minimum overall cost. This is
a balance between the capital cost of the frame and the improved revenue from
early occupation of the building through fast erection of the steel frame: a more
expensive framework may be quicker to build and for certain uses would be more
economic to a client in overall terms. Commercial office developments are a good
example of this balance. Figure 2.1 shows a breakdown of construction costs for a
typical development.
2.1.3 Influences on overall design concept
Client brief
Clients specify their requirements through a brief. It is essential for effective design
to understand exactly the intentions of the client: the brief is the way in which the
client expresses and communicates these intentions. As far as the frame designer is
concerned, the factors which are most important are intended use, budget cost limits,
time to completion and quality. Once these are understood a realistic basis for producing
the design will be established. The designer should recognize however that
in practice the brief is likely to evolve as the design develops.