A sense and a tacit belief in certain properties of symmetry is deeply rooted in almost all of us. It is intended to state here with little if any proof what is very widely known or felt about symmetry, and to apply this, initially at least, to structures which, by virtue of containing a great many similar elements symmetrically disposed, can be analysed with great facility by applying one's knowledge of symmetry.
The work has a bearing on any symmetrical structure: however, a general treatment calls for an inconvenient generality of language and of demonstration, and for this reason it is for the most part confined to plain rigid framesuch as portals and multi-storey building frames.
Simon Woolf