Reliability principles, methodology and methods for lifetime design
The aim of integrated lifetime design is to predict and optimise the lifetime quality of the designed facility (building, bridge, tunnel, harbour, road, railway, airport, etc.). Lifetime quality means the capability of a facility or its structures to fulfil the requirements of its users, owners and society over its entire planning and design life (usually 50–100 years). The dictating phase for optimising the lifetime quality of a facility or structure is the planning and design phase, when the degree of freedom is high, and the cost of the phase is low. Generic limit state design aims to fulfil the generic requirements of lifetime quality. At the integrated planning and design stage, performance-based and generic structural limit states design includes the following three classes: (1) Static and dynamic modelling and design against mechanical loads; (2) Durability and service life modelling and design against degrading physical, chemical and biological loads; (3) Usability and service life modelling and design against obsolescence loads. As static and dynamic design are comprehensively dealt with in the literature and in practice, this report focuses on the lifetime safety factor method for durability design and obsolescence design. Main focus of this article is in durability design. On the obsolescence design are presented only a short summary and a number of references, because this design is not much connected to materials research.