Navegando por Assunto "Barragens de concreto"

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Acesso aberto (Open Access)
Análise de dano em barragens de concreto através do método dos elementos finitos
(Universidade Federal do Pará, 2019-08-30) BORGES NETO, Osvaldo Sousa; PRAZERES, Plínio Glauber Carvalho dos; http://lattes.cnpq.br/6175760351403329
The mechanics of damage in continuous mediums studies the effects of degradation, in diffuse and progressive way, suffered by solid bodies under requests of mechanical or non-mechanical nature. Therein such effects are taken into account by reducing the strength and stiffness properties of the damaging material. Materials such as concrete and rocks have as their basic reason for their nonlinear behavior, micro defects in their microstructure that favor the concentration of micro tensions. These micro defects constitute what is understood as the initial damage of the material. The purpose of this work is the study of appropriate damage models for the analysis of damage mechanisms in concrete dams. For this, a linear softening isotropic damage model was used and the damage model of Cervera et al. (1996) in the analysis of two sections of concrete dams. The model of Cervera et al. (1996) stood out for presenting good results in the identification of damage as well as better describing the real aspect of the stress versus strain curve of the concrete. To validate the results, the example of a wall beam by Proença et al. (2002) in which the damage results were compatible with that of the Matlab language program.
Acesso aberto (Open Access)
Behavior prediction models and control charts for safety control of concrete dams
(Universidade Federal do Pará, 2012-06) LOPES, Romulo Antonio Chaves; SANTOS, Eurípedes Pinheiro dos; VELOSO, Luís Augusto Conte Mendes
This paper presents a study for improving measurement procedures on concrete dams based on the development of behavior prediction models using multiple regression and control charts. The series of displacements of the TA-2 concrete block crest of the Tucuruí Hydroelectric Power Plant, the largest Brazilian hydroelectric power plant, was taken as an example of application. The methodology that was used generated a behavior prediction model that is in good agreement with the measured displacements. Two types of control charts were tested, both of which identified the change in structural behavior of the block.
Acesso aberto (Open Access)
Dosagem experimental de concreto massa com adição de sílica ativa aplicado em barragem
(Universidade Federal do Pará, 2017-11-10) SOUZA, Grazielle Tigre de; GOUVEIA, Fernanda Pereira; http://lattes.cnpq.br/1772072130947378
The study of concrete dosage for large constructions, specifically of dams, has its own peculiarities due to the large volumes involved, intensifying the care with the supply and quality of materials used for these concretes, compositions with pozzolan additions are generally used in order to reduce the heat of hydration. In this sense, the main objective of this research is the elaboration of a mix design of concrete with the substitution of 8% of the cement per silica fume, the experimental study of the mix design was based on the Method of the Fineness Module of the Aggregates. To meet the proposal of this research, the methodology based primarily on the characterization of concrete constituent materials (fine and coarse aggregates, and silica fume), concrete mix design study by the Method of the Fineness Module (MFM) and subsequent analysis of the properties of the concrete mass obtained, making it possible to elaborate the concrete mix design, according to the requirements specified in the design of hydroelectric power plant structures. In this sense, with regard to the characterization of the aggregates, the results demonstrated the feasibility of the use of these in the production of concrete for dams. In relation to cement and silica fume the characteristics of these materials attend the normative requirements. The experimental dosage based on the MFM method, made it possible to compose the dosage graphs needed to define the mix design of concretes and consequently the verification of their applications in dams. It can be affirmed, thus, that the MMF approach developed in this research can be considered an important contribution, for the dissemination of the dosage methodology for concrete application in dams.