Metodologia para gestão de risco em barragens a partir de árvore de eventos e análise FMEA

Abstract

Some studies that analyze the risk of failure consider that between 2016 and 2025 about 30 major tragedies should be expected and if we evaluate the data between 1900 and 2014, there is an average of three ruptures every two years, considering only the ruptures disseminated and investigated. It can be said that failures are potentially and will be driven by the economy, since cost has been the main variable considered in the design, construction, operation, monitoring and closing plan of these structures. As companies reduce investments in maintenance, risk management and failure prevention, there is an incentive for economic recovery, competitiveness of product value and debt reduction, required by investors. The result has been a loss of labor, to the point that companies no longer have sufficient knowledge about the engineering and operational skills that apply to tailings and water management. Learning from the dams' tragedies is practically non-existent, not being a Brazilian exclusivity, bringing a catastrophic environmental and social consequence. Failures will occur as long as the tendency is for them to be seen and treated as unpredictable, without risk management. The frequency and severity of the failures are increasing globally, the majority of which would be preventable if observed due diligence on the part of dam owners and operators. Technical knowledge exists to allow dams to be built and operated at low risk, but the frequency of ruptures leads to lapses in the consistent application of expertise throughout the life of an installation and due to a lack of attention to detail. In Brazil, professional practice and regulatory guidance allow unbridled confidence in the Observational Method, a continuous, managed and integrated design process, construction control and monitoring of structures. In many of the failures, the reports indicate a series of constructive breaches in the filter and drain systems, concrete galleries, concrete bypass channels, in addition to critical operational issues over the years of operation. The best practices, the best knowledge and the best available techniques need to be main guidelines, assumed about planning, design, construction, operation, monitoring and closing plan of dams. As these guidelines become clear, and are applied, the industry will no longer depend on assumptions about observational methods, which consider the expertise and particular point of view of engineers and consultants to make important decisions that affect risk. The Baldi Method, developed in this Thesis, considers the information of inspection and instrumentation, identifying risks from event trees, separately, intolerable, tolerable and acceptable risks. The intolerable risks are conducted for FMEA-type failure analysis, where severe, intermediate and mild failures are assessed. The objective is to enable the development of an assertive and effective action plan for Dam Safety Management.