Reliability And Uncertainty Analyses In Hydraulic Design

Prepared by the Subcommittee on Uncertainty and Reliability Analyses in Design of Hydraulic Structures of the Technical Committee on Probabilistic Approaches to Hydraulics of ASCE. This report contains 13 papers presenting the application of reliability analysis to the design and safety of hydraulic structures. Several recent major failures of engineering systems have raised public concern on the safety and reliability of engineering struct.ures. Decades ago, a quantitative evaluation of the reliability of structures was not possible and engineers used safety factors that were determined mainly through experience and judgement. Recent advances in probability methods and computers make it feasible to evaluate the contributions of various technologic and natural factors to the safety and reliability of structures.ØThe first four papers in this report discuss techniques pertinent to reliability and uncertainty analyses. The next nine papers explore how these techniques can be applied to dam safety, coastal floods, and hydraulic structures. The report concludes with a reprint of an article by Vrijling on the Eastern Scheldt Storm Surge Barrier of the Delta Project in the Netherlands and the use of reliability analysis for sewer design.

Since application of reliability analysis to hydraulic engineering covers a wide scope of sub-fields, this report presents a glimpse of some of the topics pertinent to the design and safety of hydraulic structures. The first four papers discuss various techniques pertinent to reliability and uncertainty analyses.

With the expansion of new technologies, materials, and the design of complex systems, the expectations of society upon engineers are becoming larger than ever. Engineers make critical decisions with potentially high adverse consequences. The current political, societal, and financial climate requires engineers to formally consider the factors of uncertainty (e.g., floods, earthquakes, winds, environmental risks) in their decisions at all levels. Uncertainty Modeling and Analysis in Civil Engineering provides a thorough report on the immediate state of uncertainty modeling and analytical methods for civil engineering systems, presenting a toolbox for solving problems in real-world situations. Topics include Neural networks Genetic algorithms Numerical modeling Fuzzy sets and operations Reliability and risk analysis Systems control Uncertainty in probability estimates This compendium is a considerable reference for civil engineers as well as for engineers in other disciplines, computer scientists, general scientists, and students.

In 1997 disastrous flooding running through the Czech Republic, Poland, Germany took the lives of a great number of people and caused economic damage estimated in tens of billions of dollars. Flooding of the Yangtze river in 1998 killed more than 3000 people, dislocated 230 million souls, and caused direct damage of more than $ 45 billion. Both the general public and the experts are asking what we can learn from these recent events to reduce loss of life and flood damage. The 1997 floods were dealt with by experts from the Czech Republic, Poland and Germany, who presented timely reports on combatting floods, both success stories and shortcomings. This experience is further extended by reports from experts drawn from 13 other countries, developing a broad overview of flood risk management, covering the ecosystem approach to flood management, including socioeconomic issues, flood impacts on water quality, human health, and natural ecosystems.

35 leading multi-disciplinary scientists with international reputations provide reviews of topical areas of research on uncertainty and reliability related aspects of water resource systems. The volume will be valuable for graduate students, scientists, consultants, administrators, and practising hydrologists and water managers.

Failure of hydrosystems, such as dams, levees, storm sewers, or pollution control systems, pose threats to the public safety and health as well as potentially inflict enormous damages on properties and environments. Many failures of hydrosystems are mainly attributed by the existence of various uncertainties, including inherent natural randomness and the lack of complete understanding of involved geophysical processes. It is therefore essential to systematically quantify the degree of uncertainty for the problem in hand so that reliability assessment and risk-based design of hydrosystems can be made. The conventional approach of frequency analysis of heavy rainfalls or large floods consider only portion of the uncertainties involved in hydrosystem engineering problems. Over the past two decades or so, there has been a steady growth on the development and application of uncertainty analysis techniques in hydrosystems engineering and other disciplines. The aim of this book is to bring together these uncertainty analysis techniques in one book and to demonstrate their applications and limitations for a wide variety of hydrosystem engineering problems.

Fluvial Hydrosystems provides a unified approach to the study of running waters and aims to provide a scientific basis for sustainable management of rivers. It differs from traditional texts in viewing rivers as structured, four-dimensional systems and integrating ecological and geomorphological approaches to provide a holistic perspective on river dynamics. Advanced students of geomorphology, ecology, environmental science, land use and civil engineering will all benefit from this wide-ranging and stimulating textbook.

Reducing flood damage is a complex task that requires multidisciplinary understanding of the earth sciences and civil engineering. In addressing this task the U.S. Army Corps of Engineers employs its expertise in hydrology, hydraulics, and geotechnical and structural engineering. Dams, levees, and other river-training works must be sized to local conditions; geotechnical theories and applications help ensure that structures will safely withstand potential hydraulic and seismic forces; and economic considerations must be balanced to ensure that reductions in flood damages are proportionate with project costs and associated impacts on social, economic, and environmental values. A new National Research Council report, Risk Analysis and Uncertainty in Flood Damage Reduction Studies, reviews the Corps of Engineers' risk-based techniques in its flood damage reduction studies and makes recommendations for improving these techniques. Areas in which the Corps has made good progress are noted, and several steps that could improve the Corps' risk-based techniques in engineering and economics applications for flood damage reduction are identified. The report also includes recommendations for improving the federal levee certification program, for broadening the scope of flood damage reduction planning, and for improving communication of risk-based concepts.