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Since resistance against extreme environmental actions explicitly forms part of the basis of structural design, the implications of climate change emphatically needs to be considered. This paper presents the results of a survey of climate change developments in South Africa and Germany from the perspective of its rele-vance to extreme actions on infrastructure. It is concluded that the importance of climate change is broad and varied. However incorporation into practice is mostly nominal. Although general trends of climate change are confirmed, proper information on changes in extreme conditions is limited. Coastal engineering seems to be the field which is most active in providing for climate change. It is concluded that risk based methodologies developed to treat the variability and uncertainties of extreme actions and consequences in present practice provide a sound basis for treating the effects of climate change in a rational and optimal manner. It is also clear that there is strong motivation for extensive research as the best action to be taken presently, anticipating appropriate adjustment of reoptimized design methodologies.
A methodology for the evaluation of the annual probability of occurrence of post-elastic seismic damage in realistic structures is presented. The seismic damage hazard analysis (SDHA) is carried out here by coupling conventional seismic hazard analysis (SHA) for the site and the structural response to earthquakes of different intensities. The structural performance is statistically investigated by conducting appropriate non-linear dynamic analyses for a limited set of real ground-motion records that might potentially pose a threat to the structure at the site. The merging of these two approaches permits calculation of the seismic hazard faced by the structure in direct damage terms. The methodology is presented in this paper with the aid of a simple illustrative case study where the annual probability of damage and, eventually, failure of a power house steel structure is computed. This methodology can find practical applications in seismic retrofit of nuclear power plant structures and in the evaluation of seismic damage hazards in new structure designs.
Prescriptive and risk-based methods including qualitative, semi-quantitative and quantitative approaches exist for the risk assessment of road tunnels. This paper provides an overview and a brief discussion of these methods and uses representative traffic and accident data in Greece in a typical tunnel conforming with the minimum infrastructure requirements of the European Directive 2004/54/EC to compare and discuss the resulting risk for each of these methods. Conclusions regarding the implementation of risk analysis methods and the use of the associated existing national guideline are drawn and recommendations for further developments in standards are provided. An integrated framework for the optimal selection of safety measures based on risk reduction and socio-economic considerations is proposed and its applicability in risk analysis of road tunnels is discussed. (C) 2016 Elsevier Ltd. All rights reserved.
Solar energy represents a clean, natural and sustainable source of energy. Solar photovoltaic panels can be installed on roofs of structures or in the ground. This contribution focusses on ground-mounted systems, which are presently widely implemented. At present limited guidelines on the design of solar ground-mounted structures are available. Usually standards for the design of normal buildings are applied. However, the design of ground-mounted structures significantly differs from common structural design by: (1) a lower design lifetime (20-25 years) is accepted; (2) failure is not associated with the loss of human life; (3) resistance uncertainties need due attention; (4) uplift wind forces dominating structural reliability are associated with a large scatter. That is why the reliability analysis and optimal design of ground-mounted solar systems is investigated herein. The failure costs and especially their ratio to the initial costs are analyzed considering the data provided from the industry. Probabilistic reliability analyses are carried out and optimum design levels are computed for representative cost ratios. The optimal target reliability depends on the ratio between failure and initial costs; reliability index of 3.5 corresponds to a reasonable cost ratio of 10.
The contribution demonstrates the benefits of Unmanned Aerial Vehicles (UAV)-based surveys for building damage evaluation and decisions on interventions after an earthquake. The case study focuses on the historic village of Castelluccio di Norcia (Italy), heavily damaged by the 2016 earthquake. By constructing a 3D model based on UAV flights, the damage levels are estimated for buildings in the village and an optimal set of intervention measures is proposed. For the decision analysis, a pre-posterior Bayesian technique is utilized. The efficiency of the UAV-based survey is highlighted through a cost-benefit analysis and by considering parameters such as the time constraints, the quality of obtained data and the risk of inspecting persons. The proposed method seems to be efficient in organizing rescuing activities, managing emergency measures and specifying interventions, following the occurrence of an accidental situation.
The contribution presents a methodological procedure for the management and planning of interventions after earthquake events in small historic centres. Reference is made to the case study of Castelluccio di Norcia, a village in the Apennine Mountains affected by the seismic sequence that hit Central Italy in 2016. The earthquake risk of the area and the damaging events of 2016 are critically reviewed. The implementation of cognitive analysis and the application of advanced survey techniques involving the use of nmanned Aerial Vehicles (UAVs) for the purposes of emergency management and monitoring of damaged areas are analysed. The outcomes, combined with the direct involvement of the local population, represent a complete and integrated approach allowing the definition of a) possible intervention strategies, b) related decision criteria and c) practical recommendations for the reconstruction and regeneration of Castelluccio, and, in general, of small historic centres damaged by catastrophic events.
Natural and technological hazards have a major impact on environmental and human safety. Risk assessment plays an essential role in the risk management of the effects of such hazards. This contribution summarizes first the general formulation of risk depending on two parameters: hazard probability and associated consequences. Problems faced in industrial applications based on the experience of the author are discussed. Risk acceptance criteria for the contributors to risk i.e. human, economic and environment are critically reviewed. Resilience based criteria are also included and conclusions for future developments are provided.
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.