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In this compilation, the contributions published as extended abstracts of the 16th International Probabilistic Workshop 2018 in Vienna are collected. This article is also published in the Wiley Online Library (WOL) at https://doi.org/10.1002/best.201800059. In addition to these Extended Abstracts, all contributions can be found online as a Full Paper on the same doi in the corresponding and so called Supporting Information.

Risk and reliability criteria are well established in many industrial sectors such as the offshore, chemical or nuclear industries. Comparative risk thresholds have been specified to allow a responsible organization or regulator to identify activities, which impose an acceptable level of risk concerning the participating individuals, or society as a whole. The scope of this contribution is to present target reliability criteria based on acceptable human safety levels. Application of theoretical principles is illustrated by examples of railway engineering structures. Initially it is shown how civil engineering structures for which human safety criteria play a role are classified according to Eurocodes. Examples include bridges, tunnels or station buildings. The general concepts for risk acceptance are then briefly reviewed, particularly in their relation to the target reliability criteria. The distinction between the two types of criteria is made: group risk and the acceptance criterion based on the Life Quality Index LQI approach introduced by ISO 2394:2015. The differences between the criteria for new and existing structures are discussed. The application is illustrated by an example of a bridge crossing an important railway line. It appears that while benefits and costs of a private stakeholder or public authority are reflected by economic optimisation, the society should define the limits for human safety to achieve uniform risks for various daily-life activities and across different industrial sectors.

Many heritage structures do not fulfil requirements of present standards. Decisions about adequate construction interventions should be based on complex assessment of structural reliability. Such an assessment should take into account new utility plans, actual material properties and environmental influences, including degradation processes, satisfactory past performance and advanced modelling reflecting properties of historic materials that are often distinctly different from those assumed for current construction materials.The submitted contribution focuses on reliability assessment of balcony girders of the Estates Theatre in Prague, listed as a Czech national heritage monument. Preliminary reliability assessment, based on conservative recommendations of standards for existing structures, reveals that the resistance of the wrought steel girders from the 19th century is insufficient. This is why a series of non-destructive tests supplemented by a single tensile test are performed in order to obtain information about the homogeneity of the historic material, its strength and modulus of elasticity. The results of the tests are then evaluated using statistical methods. The design values of basic variables are estimated, considering uncertainties in material properties, geometry and resistance models. In addition, chemical analysis is performed to identify material composition and verify a type of historic steel.