Structural Design for Architecture
Fig. 3.44 Ice Rink, Oxford, 1984. Nicholas Grimshaw &
Partners, architects; Ove Arup & Partners, structural
engineers. The mast-and-tie system was used here to
achieve a large column-free interior. The prevailing ground
conditions were a factor in the selection of this particular
structural configuration. [Photo: Ove Arup & Partners]
points. The justification for the elaborate mast-
and-tie system is normally that it allows a
large column-free interior to be achieved,
either because this is a space-planning
requirement (as was the case at the Oxford Ice
Rink) or because great flexibility is needed in
the planning of the interior arrangements of
the building.
3.6.3 Low- and medium-rise multi-storey
frames
3.6.3.1 Introduction
In low- and medium-rise multi-storey frames,
that is frames with up to 30 storeys, the princi-
pal structural factor which affects the plan
arrangement is the need to provide a suitable
system of beams and columns to support the
gravitational load on the floors. The need for
the structure to have adequate lateral strength
to resist wind load is, of course, also an impor-
tant consideration, particularly with the higher
structures.
3.6.3.2 The floor grid
In most multi-storey frames the floors are of
reinforced concrete. A number of different
types of floor slab are used including in situ or
precast concrete slabs with simple rectangular
cross-sections, voided precast slabs of various
kinds, and in situ slabs which are cast on a
permanent formwork of either steel or precast
concrete (Fig. 3.45). The concrete slabs are
normally made to act compositely with the
floor beams to improve the overall efficiency of
the structure (Fig. 3.46). The floor slabs are
almost invariably of the one-way-spanning type
and must be supported on a parallel system of
beams spaced 2 m to 6 m apart depending on
the slab type.
The column grid can take various forms
depending on the space-planning require-
88 ments of the building. A very common basic
