Qualitative Analysis of Structures

A variety of opinions were expressed by the participants at the Cambridge colloquium, as they had been asked to present their thoughts on design life from different viewpoints. The debates ranged widely as new opinions were outlined. For this colloquium the main opinions have been assembled and examined by pairs of presenters as client requirements, legal and organisational, and technical considerations. It is evident that there is considerable agreement on some of the principles and some of the difficulties which the concept of design life entails. So how best to make progress and signpost the way ahead? D.W. Quinion

Identification of what needs to be inspected, when and how It is not possible to inspect economically all parts of a building or civil engineering structure. The rear face of a basement wall against which backfill has been placed or the condition of the embedded length of concrete or steel piles are examples of items which are extremely expensive to inspect. They have therefore to be detailed appropriately. Any structure should be classified into areas or items which cannot be inspected regularly, those which may be inspected regularly, and those which definitely need to be inspected frequently. This classification should be carried out at the design concept stage: it is the responsibility of the design team. M.S. Fletcher

There are probably relatively few cases where a client and designer embark on a project with an explicit statement of working life, and in the absence of reliable data on the service life and maintenance costs of various forms of construction, a client may take the easy option of accepting contemporary norms of quality, which may imply no more than the minimum to comply with statutes and national standards. H.P. Webber