Assessment and safety requirements for existing structures

Abstract

Extending life of existing structures should be supported by guidelines or technical rules. In the case of historic buildings, besides the technical, economic and social aspects to be taken into account, the historic importance may determine the level of intervention to be performed. In spite of that, the integrity of the building itself and protection to people must be safeguarded and structural safety must reach a minimum level. However, safety requirements are not always established. Some European countries have national regulations and standards regarding assessment and retrofitting of existing structures. There is a need for harmonised European technical rules on this subject which can be broadly accepted. This paper refers the existing design codes and the work under way to extend them to existing structures and discusses their application and limitations regarding historic buildings. Based on LNEC experience, an approach is also proposed concerning the safety requirements applicable to heritage buildings, discussing the suitability of specifying different target reliability levels. Those levels should depend on the heritage value of the structure and the consequences of a possible failure of the structure, thus linked to its acceptable use.