STRUCTURAL DESIGN FOR ARCHITECTURE

provide adequate vertical support for all areas
of floor and roof depend on the type of floor
and roof system which is used and, in particu-
lar, on whether one-way- or two-way-spanning
systems are employed. Typical one-way-
spanning systems for masonry buildings are
the traditional timber joisted floor and the
traditional rafter or trussed-rafter roof (see
Section 6.7.2); precast concrete slabs and one-
way-spanning in situ reinforced concrete slabs
are two other common examples (Fig. 5.21).

Examples of two-way-spanning systems are the

in situ reinforced concrete floor slab and the

steel space-deck roof structure (Fig. 5.22).

Four basic plan types are employed for

masonry buildings: spine-wall, cross-wall,

cellular and core-type (Fig. 5.23). Note that

these are the basic forms in which only the

primary loadbearing walls are shown. Extra

structural walls are usually required for lateral

stability, particularly in the spine- and cross-

wall forms, and most building plans also

contain a number of non-structural walls in

addition to the structural walls, because these

are necessary to achieve the required arrange-

ment of internal spaces. The plans of real

buildings, of which those shown in Fig. 5.24

are typical, are therefore much more compli-

cated than the basic forms, which are shown

Masonry structures

Fig. 5.21 Typical one-way-spanning floor structures in

loadbearing-wall buildings.

(a) Timber joists supported on joist hangers.

(b) Precast concrete slabs.

(c) Lightweight steel joists.

Fig. 5.22 Two-way-spanning structures.

(a) In situ reinforced concrete slab.

(b) Space framework. 165

(a)

(b)

(c)

(b)

(a)