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286 Barry’s Advanced Construction of Buildings
Photograph 5.2 Skeleton frame with concrete lift shaft core.
Skeleton frame
The conventional steel frame is constructed with hot-rolled section beams and columns in
the form of a skeleton designed to support the whole of the imposed and dead loads of
floors, external walling or cladding and wind pressure (Photograph 5.2). The arrangement
of the columns is determined by the floor plans, horizontal and vertical circulation spaces
and the requirements for natural light to penetrate the interior of the building. Figure 5.9
is an illustration of a typical rectangular grid skeleton steel frame. In general, the most
economic arrangement of columns is on a regular rectangular grid with columns spaced
at 3.0–4.0 m apart, parallel to the span of floors which bear on floor beams spanning up to
7.5 m with floors designed to span one way between main beams. This arrangement provides
the smallest economic thickness of floor slab and least depth of floor beams, and
therefore least height of building for a given clear height at each floor level.
Figure 5.10 is an illustration of a typical small skeleton steel frame designed to support
one-way span floors on main beams and beams to support solid walls at each floor level
on the external faces of the building. This rectangular grid can be extended in both directions
to provide the required floor area.
Where comparatively closely spaced columns may obstruct internal floor space, a larger
rectangular or square grid of columns is used. The columns support main beams, which
in turn support secondary beams spaced at up to 4.5 m apart to carry one-way span floor
slabs, as illustrated in Figure 5.11 and Photograph 5.3. This arrangement allows for the least
span and thickness of floor slab and the least weight of construction.