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The results of a survey of climate change developments in South Africa and Germany from the perspective of its relevance to extreme actions on infrastructure are presented in this paper. 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 re-optimised design methodologies.
Environmental and climate change is a global issue that will and has already impacted the frequency and intensity of natural hazards in many regions throughout the world. Consequently, the actions on structures will be changing and present design practices will need to be adapted to provide for reliable structures with service lifetimes spanning over decades and centuries. A submitted review of present environmental and climate change information is focused on the distinct, but complementary climatic conditions of Central Europe and South Africa. An outline of the basis of structural design accounting for extreme wind and snow loads is presented and recommendations for future risk-based design procedures are discussed.
Issues to consider include:
a) use of extreme value models;
b) implementation of changes in distribution parameters to obtain extremes with long return periods;
c) consideration of the rate of the change.
The example of a representative structure illustrates the effects of climatic actions on structural reliability. It appears that uncertainties related to the lack of observations hinder drawing strong conclusions concerning appropriate modifications of design procedures due to environmental and climate change. Uncertainties in the prediction of environmental and climate change have a direct bearing on optimal levels of reliability and the subsequent derivation of design values.
The principles of structural reliability are sufficiently advanced to be used extensively to develop design standards even at international level. The concept of limit states is generally accepted and implemented. Present standards are however to a large extent based on past experience, rather than on quantitative reliability modeling. It appears that reliability principles and models can bridge the gap between probabilistic assessment and operational design. Representative theoretical models are presented to indicate how judgment based reliability concepts can be complemented or replaced by the use of such models. The importance of reliability levels, reference period, design working life, specified characteristic values of basic variables and methods to derive their design values from reliability procedures are demonstrated. On this basis a standardized basis of structural design can be formulated to convert the reliability principles (such as provided by ISO 2394) into operational design procedures (such as used by EN 1990 and other standards). It is concluded that reliability principles and models could contribute further to international harmonization of structural design.
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.