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Standards for the design of bridges, buildings and other infrastructure specify design loads for climatic hazards such as temperature, snow, wind, and floods based on return periods presented in maps or tables that account for regional differences. These design loads were developed from statistical analyses of historical hazard data under the assumption that the past is representative of the future. Climate change may affect the frequencies and intensities of environmental hazards which, depending on regional variations, raises questions as to whether structures designed to current specifications will meet minimum safety standards over their future service lives. This paper critically appraises issues related to using historical hazard data for future designs. It reviews basic principles of uniform reliability, that modern design codes use as the basis for ensuring minimum levels of safety, describing the relationship between hazard return periods, structural reliability, risk and the maximum loads expected within a structure's service life. Simple examples involving wind effects on structures demonstrate how to calibrate structural design hazard maps for climate-related extreme events to meet the minimum standards of safety implied in current specifications. The paper also introduces a possible practical approach to account for climate change when designing new structures and assessing the safety of existing facilities. [ABSTRACT FROM AUTHOR]

In Italy, the recent regulatory and legislative developments relevant to the seismic risk mitigation of the existing building stock aim to propose tax deductions and simple but reliable approaches for the quantitative evaluation of the beneficial impacts of seismic retrofitting. Nevertheless, currently policy makers need tools and models able to assess the seismic risk and the cost/benefit of the strengthening interventions at regional/national level in order to plan future mitigation policies and be aware of the effectiveness of measures taken. To this aim, this article proposes a heuristic vulnerability model for large-scale applications. Starting from macroseismic approaches widely used in Europe, fragility and vulnerability curves for masonry and RC buildings are calibrated using a specific procedure based on the new Italian 'guidelines for the seismic risk classification of constructions' approved in January 2020, namely the so-called 'Sisma Bonus.' According to the construction material, building type and number of floors, the developed curves are defined in terms of vulnerability and height classes. The derived vulnerability model can be used in exposure models which rely on poor census data. Finally, it is compared with existing vulnerability models and the comparisons are analysed to demonstrate the effectiveness of the proposed model. [ABSTRACT FROM AUTHOR]