Modern engineering structures should ensure an economic design, construction and operation of structures in compliance with the required safety for persons and the environment. In order to achieve this aim, all contingencies and associated consequences that may possibly occur throughout the life cycle of the considered structure have to be taken into account. Today, the development is often based on decision theory, methods of structural reliability and the modeling of consequences. Failure consequences are one of the significant issues that determine optimal structural reliability. In particular, consequences associated with the failure of structures are of interest, as they may lead to significant indirect consequences, also called follow-up consequences. However, apart from determining safety levels based on failure consequences, it is also crucially important to have effective models for stress forces and maintenance planning. The present contributions of this proceeding covers both issues of maintenance and assessment of structures from a traditional engineering perspective and issues of natural hazards. Models developed in recent years are discussed, including algorithms for assessing uncertainty in the domains of stress forces and resistance for maintenance- and risk planning. In traditional engineering, the identification of cost efficient maintenance strategies for structures usually has its basis in condition assessments achieved through inspections, tests and monitoring. It is well recognized that such condition assessments are subject to significant uncertainties and, in general, at best provide indications rather than observations about the condition of the structure. Probabilistic frameworks for the quantification of inspection, of predictable future degradation, of estimated remaining service life and the expected service life costs of the structure are some of the topics of the contributions. One possibility to mitigate natural hazards is the the implementation of technical protection measures. In this case the same considerations as above about safety assessment and associated uncertainties are valid. For the risk analysis of natural hazards such as gravitational mass movements important steps include the determination of the magnitude and frequency of hazardous events, the delineation of the endangered area (often equal to the runout zone), and the estimation of relevant intensity parameters such as impact pressure. This volume includes contributions which discuss uncertainties related to the design of technical protection structures against natural hazards. Other contributions deal with uncertainties which are involved in the hazard assessment and risk analysis of processes such as floods, landslides, debris flows, and snow avalanches.
