1. Philosophy of design

This chapter is concerned with the philosophy of struc
tural design. The chapter describes the overall aims of
 design and the many inputs into the design process.
 The primary aim of design is seen as the need to ensure
 that at no point in the structure do the design loads
 exceed the design strengths of the materials. This can be
 achieved by using the permissible stress or load factor
 philosophies of design. However, both suffer from draw
backs and it is more common to design according to
 limit state principles which involve considering all the
 mechanisms by which a structure could become unfit
 for its intended purpose during its design life