The main aim of the book, i.e. to provide a text for final year undergraduate
and for postgraduate students, remains the same as for the previous
two editions; we also hope that researchers, designers and operators of the
many types of structures covered in the book will continue to find the text
of interest and a stimulating, up-to-date reference source.
It is now almost six years since the manuscript of the second edition
was completed and this new edition gave us the opportunity to correct the
few remaining errors and to update the text and references throughout. At
the same time, as a reaction to some important developments in the field,
certain parts of the text have been rewritten, enlarged or reorganized.