@article{DiamantidisHolickySykora, author = {Diamantidis, Dimitris and Holicky, Milan and S{\´y}kora, Miroslav}, title = {Reliability and Risk Acceptance Criteria for Civil Engineering Structures}, series = {Transactions of the VSB - Technical University of Ostrava, Civil Engineering Series}, volume = {16}, journal = {Transactions of the VSB - Technical University of Ostrava, Civil Engineering Series}, number = {2}, publisher = {De Gruyter}, pages = {1 -- 10}, abstract = {The specification of risk and reliability acceptance criteria is a key issue of reliability verifications of new and existing structures. Current target reliability levels in standards appear to have considerable scatter. Critical review of risk acceptance approaches to societal, economic and environmental risk indicates that an optimal design strategy is mostly dominated by economic aspects while human safety aspects need to be verified only in special cases. It is recommended to specify the target levels considering economic optimisation and the marginal life-saving costs principle, as both these approaches take into account the failure consequences and costs of safety measures.}, language = {en} } @inproceedings{HolickyDiamantidisSykora, author = {Holick{\´y}, Milan and Diamantidis, Dimitris and S{\´y}kora, Miroslav}, title = {Effects of Quality Control on Reliability of Reinforced Concrete Structures according to Eurocodes}, series = {fib Symposium 2016 : Performance-Based Approaches for Concrete Structures, 14, 2016, Cape town}, booktitle = {fib Symposium 2016 : Performance-Based Approaches for Concrete Structures, 14, 2016, Cape town}, abstract = {The effect of quality control on structural reliability represents an increasingly important concern of designers and thus is investigated in this contribution, focusing on reinforced concrete structures. Recent European documents for structural design - Eurocodes, fib Model Code 2010 and ISO 2394:2015 for general principles on structural reliability indicate that the partial factors may be adjusted to available information on the quality control of structures. In particular, the partial factors for concrete and steel strength may be significantly reduced taking into account actual execution quality and related available data. Using probabilistic methods of structural reliability, effects for execution quality are investigated in this contribution considering two fundamental reinforced concrete members: a beam (or slab) exposed to bending and a short column exposed to compression. It is shown that the reliability of reinforced concrete members may vary with the load ratio of variable and permanent actions. It appears also that the structural members of a basic quality, designed using unreduced partial factors, have a greater reliability level than the members of an increased quality, designed using the partial factors reduced according to EN 1992 1 1. This provides the basis for recommendations for further code developments.}, language = {en} } @inproceedings{SykoraHolickyDiamantidis, author = {S{\´y}kora, Miroslav and Holicky, Milan and Diamantidis, Dimitris}, title = {Target Reliability for Existing Civil Engineering Systems}, series = {2016 Second International Symposium on Stochastic Models in Reliability Engineering, Life Science and Operations Management (SMRLO), 15-18 Feb. 2016, Beer Sheva, Israel}, booktitle = {2016 Second International Symposium on Stochastic Models in Reliability Engineering, Life Science and Operations Management (SMRLO), 15-18 Feb. 2016, Beer Sheva, Israel}, publisher = {IEEE}, doi = {10.1109/SMRLO.2016.28}, pages = {109 -- 114}, abstract = {Specification of the target reliability levels is one of the key issues of the assessment of existing systems. ISO 2394:2015 indicate procedures for specification of the target reliability levels by optimisation of the total cost related to an assumed remaining working life of a structural system. These approaches are critically compared with human safety criteria and with recommendations of present standards. It appears that the requirement on the same target reliability levels for existing civil engineering systems as for newly designed is uneconomical. Decisions in the assessment can result in the acceptance of the actual state or in upgrade of the existing structure, two reliability levels are thus needed - the minimum level below which the structure is unreliable and should be upgraded, and the target level indicating an optimum upgrade strategy. When reliability of a system or its key component is verified (as compared to design of a common component), the target reliability index should be increased by about 0.5.}, language = {en} } @inproceedings{SykoraMarkovaDiamantidis, author = {S{\´y}kora, Miroslav and Markova, Jana and Diamantidis, Dimitris}, title = {Bayesian Network Application for the Risk Assessment of Existing Energy Production Units}, series = {2016 Second International Symposium on Stochastic Models in Reliability Engineering, Life Science and Operations Management (SMRLO), 15-18 Feb. 2016, Beer Sheva, Israel}, booktitle = {2016 Second International Symposium on Stochastic Models in Reliability Engineering, Life Science and Operations Management (SMRLO), 15-18 Feb. 2016, Beer Sheva, Israel}, publisher = {IEEE}, doi = {10.1109/SMRLO.2016.116}, pages = {656 -- 664}, abstract = {A Bayesian network is applied in this contribution in order to assess the risks of a selected production unit in a fossil power station. A general framework for the risk assessment of production units of a power station is presented first by implementing statistical methods and Bayesian networks. Special emphasis is given to the input data consisting of failure rates which are obtained on the basis of recorded data and expert judgements. The consequences of failure are divided into economical and human (societal): economic consequences include outages of key technological devices, societal consequences cover potential injuries and fatalities. Probabilistic risk assessment methods are applied to the selected production unit of a power station. The influence of the uncertainties in the considered technical parameters on the availability of the unit is assessed and the acceptance of the calculated availability represented through the mean value and the standard deviation is discussed. Societal risks given in terms of weighted injuries and fatalities are obtained and respective risk acceptance criteria are presented. Uncertainties affecting the risks are discussed. It appears that the proposed framework provides a valuable assessment of the influence individual devices and their components on availability and societal risk. For that purpose the used methodology, intentionally simplified for operational applications, includes important factors affecting risks of production units. It is concluded that Bayesian networks are a transparent method for the probabilistic risk assessment of complex technological systems. The results of the performed analyses can be easily updated when additional information becomes available as illustrated in characteristic examples.}, language = {en} } @article{SykoraHolickyDiamantidis, author = {S{\´y}kora, Miroslav and Holick{\´y}, Milan and Diamantidis, Dimitris}, title = {Probabilistic updating in the reliability assessment of industrial heritage structures}, series = {Heron}, volume = {59}, journal = {Heron}, number = {2/3}, publisher = {Stevin-Laboratorium, TU Delft}, address = {Delft}, issn = {0046-7316}, abstract = {Assessment of existing structures should be based on the actual as-built conditions concerning geometry, material properties, loading and environmental conditions. A crucial step of the assessment consists in updating of prior information by newly obtained measurements which may be conducted by Bayesian approach. Updating of probabilistic distributions of basic variables or direct updating of failure probability can be effectively used. Application of theoretical principles is illustrated by a case study of a historic factory built in 1900s. The paper is a tribute to Ton Vrouwenvelder for his essential contributions to developments of theory and promotion of practical applications of probabilistic assessment of existing structures.}, language = {en} } @inproceedings{DiamantidisHolickySykora, author = {Diamantidis, Dimitris and Holick{\´y}, Milan and S{\´y}kora, Miroslav}, title = {Risk and reliability acceptance criteria for civil engineering structures}, series = {Structural Reliability and Modelling in Mechanics Conference, Ostrava, Czech Republic, May 2016}, booktitle = {Structural Reliability and Modelling in Mechanics Conference, Ostrava, Czech Republic, May 2016}, pages = {1 -- 10}, abstract = {The specification of risk and reliability acceptance criteria is a key issue of structural design and verification of existing structures. Current target reliability levels in standards appear to have considerable scatter. Critical review of risk acceptance approaches to societal, economic and environmental risk indicates that an optimal design strategy is mostly dominated by economic aspects while human safety aspects need to be verified only in special cases. It is recommended to specify the target levels considering economic optimisation and the marginal life-saving costs principle, as both these approaches take into account the failure consequences and costs of safety measures.}, language = {en} } @inproceedings{DiamantidisSykoraBarnardoViljoenetal., author = {Diamantidis, Dimitris and S{\´y}kora, Miroslav and Barnardo-Viljoen, Celeste and Retief, Johan Verster and R{\´o}zs{\´a}s, {\´A}rp{\´a}d}, title = {On Risk-Based Design of Structures Exposed to Changing Climatic Actions}, series = {Life-Cycle of Engineering Systems : Emphasis on Sustainable Civil Infrastructure ; The Fifth International Symposium on Life-Cycle Civil Engineering (IALCCE 2016) 16-20 October 2016, Delft, The Netherlands}, booktitle = {Life-Cycle of Engineering Systems : Emphasis on Sustainable Civil Infrastructure ; The Fifth International Symposium on Life-Cycle Civil Engineering (IALCCE 2016) 16-20 October 2016, Delft, The Netherlands}, editor = {Bakker, Jaap and Frangopol, Dan M. and Van Breugel, Klaas}, publisher = {Taylor \& Francis}, address = {London ; Boca Raton}, isbn = {978-1-138-02847-0}, language = {en} }