PRR Project

Summary

1. TASKS TO BE ASSIGNED TO THE PROSPECTIVE EMPLOYEEThe science and technology activities (STA) in which the prospective employee will be involved include research and development (R&D) and science and technology services (STS) in the field of dam engineering, concerning numerical modelling and structural analysis of dams whose concrete is affected by internal expansion reactions. The main tasks to be accomplished are:a) Acquire knowledge about the expansive phenomena and its modelling, considering the thermo-hygrometric conditions, and about the structural modelling, including the delayed and nonlinear behaviour of the concrete.b) Improve the numerical tools for modelling the structural effects of concrete expansions in dams.c) Contribute to develop computational codes for the analysis of concrete structures over timed) Calibrate the numerical models by applying them to simple case studies for which laboratory test or monitoring results are available, and application of the numerical models to interesting and challenging case studies.e) Prepare research proposals and participate in national and international research projects.f) Publish and present papers with the research results.g) Train young researchers in MSc and PhD programs.2. SCIENTIFIC PROFILE REQUIREDGiven the tasks to be accomplished, the scientific profile required to the prospective employee should include:a) A PhD in Civil Engineering, with a strong component in structural engineering.b) A background in numerical modelling for structural analysis using the finite element method.c) Experience in computer programing and advanced software development.d) Ability to analyse problems critically.e) Good teamwork skills in national and international environments.3. RATIONALE TO HIRE FOR THE SCIENTIFIC AREASince its founding, LNEC has been actively engaged in science and technology activities in dam engineering and has played a pioneering role in the development of models and methods to interpret the structural effects of concrete expansions. LNEC has established itself as a reference in this field and receives continuous requests for services from government agencies and large owners of important dams affected by concrete swelling in Portugal and abroad.The existence of researchers with the adequate profile to accomplish the identified tasks is relevant for LNEC. Indeed, its role and responsibilities as provider of high-level science and technology services require continuous development of research to keep the high standards for which LNEC is known in this domain. It is therefore necessary to timely reinforce LNEC’s team and hire an Assistant Researcher to further develop state-of-the-art models and technologies and to address the upcoming challenges.4. RELEVANCE OF THE SCIENTIFIC PROFILE OF THE PROPOSED POSITION IN THE CONTEXT OF THE STATE-OF-THE-ARTThe expansive internal reactions of concrete, which include the alkali-aggregate reaction and the internal sulphate reaction, lead to the concrete expansion in the presence of water. The induced damages vary, depending on chemical and environmental conditions, ranging from small scattered surface cracks, for moderate expansions, to large cracks with material separation, in case of severe expansions, that can critically endanger the structural safety.Internal reactions of concrete are one of the main causes of premature deterioration of concrete dams. In Portugal there are around sixty large concrete dams under continuous monitoring, with about one-third of them being affected by expansive reactions of internal concrete source.The chemical, petrographic, and microscopic analyses, combined with mechanical tests on cores extracted from the structures, provide valuable information about the internal damage of concrete and the potential remaining expansion. These data, along with monitoring and inspection results, provide the necessary elements for conducting simulation studies to interpret the behaviour of structures, evaluating their safety and supporting the study of the best interventions to be carried out on the structures.At LNEC there already exist numerical tools for performing such studies, which have been used in studies on the Pracana, Santa Luzia, Fagilde, Bemposta and Covão do Meio dams in Portugal, as well as Cahora Bassa Dam (Mozambique) and Peti Dam (Brazil). However, the capabilities of these tools are still limited in some aspects and have to be improved.The tasks to be accomplished and the required scientific profile enable relevant contributions to the state-of-the-art in numerical modelling of dams affected by concrete swelling. At the same time, this makes this scientific profile particularly relevant and appealing for a qualified young researcher.