STRUCTURAL DESIGN FOR ARCHITECTURE

which the individual cells are approximately

square and approximately the same size.

2 The plan geometries of multi-storey build-

ings are kept more-or-less the same at every

level. It is particularly important that

loadbearing walls should be continuous

throughout the entire height of a building.

3 Attention is paid to the slenderness ratios

of walls and columns. Storey heights are no

larger than is necessary and long sections of

plane wall are avoided. A wall thickness is

selected which gives a slenderness ratio of

less than 20.

5.3.3 Provision of overall stability and lateral

strength

5.3.3.1 Introduction

As with most types of structure, the issue of

the overall stability of a masonry building can

be considered together with that of its ability

to resist horizontal load. If, in addition to

gravitational load, the building can resist

horizontal load from two orthogonal directions

then it will also be geometrically stable.

The action of horizontal load on a masonry

building has two consequences which affect its

planning. Firstly, it requires that the building,

taken as a whole, should have the ability to

resist its effect (Fig. 5.30a). The building must,

Fig. 5.31 Typical wind-
bracing system for a
loadbearing-wall structure.
Wind pressure loads are
applied initially to the
surfaces of the external
walls and are transmitted by
the horizontal-plane floors
and wind girders to walls
which are parallel to the
wind direction and which
act as diaphragm bracing in
the vertical plane.

171

Masonry structures

Fig. 5.30 The effect of wind loading on a masonry

structure.

(a) The structure, taken as a whole, must be capable of

withstanding the horizontal load.

(b) Individual walls must have sufficient bending strength

to resist the out-of-plane pressure loads.

(b)

(a)

Floor acting as horizontal-plane bracing

Wind girder incorporated into plane of ceiling