0‘quv materiallari (ma’ruza matni)

example of social needs changing with time, e.g.
lifts (elevators) or bathrooms. Likewise, offices
may be of the open plan type or they may consist
of numerous separate rooms Where there is a social
usage change, the ‘old’ style may be a disadvantage
in that a modification of the structure
may be more expensive than demolition followed
by a new design. And paying in advance for a
more expensive structure in the first place is uneconomical
and may also discourage construction.
But these issues are outside the scope of this book. So, if I do not enthuse over sustainability, it is not because of my ignorance.
In writing the fifth edition, and especially in including references to new standards, I have been greatly assisted by Robert Thomas, Manager,
Library and Information Services of the Institution
of Structural Engineers and by Rose Marney, Library Manager and Debra Francis,
Librarian, of the Institution of Civil Engineers.