ABSTRACT
The simplest way of describing the function of an architectural structure is to say that it is the part of a building which resists the loads that are imposed on it. A building may be regarded as simply an envelope which encloses and subdivides space in order to create a protected environment. The surfaces which form the envelope, that is the walls, the floors and the roof of the building, are subjected to various types of loading: external surfaces are exposed to the climatic loads of snow, wind and rain; floors are subjected to the gravitational loads of the occupants and their effects; and most of the surfaces also have to carry their own weight (Fig. 1.1). All of these loads tend to distort the building envelope and to cause it to
