Many existing structures have to be assessed to find out whether they still satisfy the demands of structural safety. There are various possibilities to be regarded: structures can be still in good condition, but exposed to traffic loads which are larger than assumed in the original design. Moreover structures can sufferer material deterioration, reducing the bearing capacity. Finally structures may originally have been designed according to rules which are not anymore in agreement with the actual demands. So, non-compliant details may lead as well to insufficient structural safety.

In order to be able to determine the actual structural safety, the structural performance of existing structures should be described as realistically as possible. The bulletin is a state of-the-art report treating many subjects related to structural safety of existing structures. This includes determination of the residual capacity of structures subjected to higher loads than initially assumed. Moreover it deals with the change of the properties of structural materials suffering deterioration and the determination of the residual bearing capacity of structures with those deteriorated materials. Also examples are given with regard to the determination of the structural safety of structures with various types of non-compliant details.

Finally attention is given to assessment of existing structures by numerical simulation and by proof loading.

https://www.fib-international.org/publications/fib-bulletins/modelling-structural-performance-of-existing-concrete-structures-pdf-detail.html