scope:

Ageing model

The objective of the CWA is to elaborate a standard framework for the results of the IRIS Project, while it is recognized that there cannot be one extensive methodology fit for all specific industries.

There is a simple basic model with considerable uncertainties, which is improved step by step through introduction and evaluation of new knowledge gained about a structure. The ideal result is a precise assessment of the condition with reasonable margins of uncertainty. The model is able to show the successive impact during the long-term deterioration process as well as the effect of sudden changes in condition (retrofit actions of local failure). It is recognized that the individual results from visual inspection and assessment will influence the quality of the prediction. Nevertheless after a number of assessments these uncertainties will be reduced to reasonable levels.

It is acknowledged that the basic model shall be kept simple and transparent for the end-users. In return the background computation is expected to become more and more complex with every new knowledge and methodology developed.

In further consequence the focus of the CWA is on the area of bridge infrastructure, as there the most mature status within the IRIS Project has been reached.

The aspect of acceptance of structural failure and accidents is always depending on the involved individual society. The current document already reflects the current situation in Austria, Germany, the Netherlands and the USA.