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The present study explores methods and tools for the practical application of explicit risk analysis methods. Structure-related risks to persons are established on the grounds of the probability of structural failure and its consequences in terms of loss of human life. The procedure adopted is applied to a representative set of structures for densely occupied buildings, for which explicit risk- analysis is of particular interest in light of the potentially high consequences to personal integrity. Acceptance criteria for risks to persons associated with such structures are deduced from the findings. These criteria provide a rational basis for decision-making in structural engineering. They may be used in explicit risk analysis or as a basis for the consistent calibration of simplified models and partial factors for structural design and assessment of existing structures.

The assessment of an existing structure to determine its suitability for present and future use entails different sorts of problems than encountered when designing new structures. The differences revolve essentially around the nature of the information available. In existing structures, deteriorated or otherwise, the accuracy of the models used for such assessments can usually be improved by acquiring more data. The Spanish Technical Building Code defines a procedure for the evaluation of existing structures that includes the same verification format as normally applied for designing new structures, but in which the representative values for the variables and the partial factors may be modified on the basis of updated information. Tools intended for such modifications, developed for the safety assessment of existing sound and deteriorated concrete structures, are applied to the structural assessment of the main dome over La Laguna cathedral, Tenerife, Spain.