Programa de Pós-Graduação em Engenharia de Infraestrutura e Desenvolvimento Energético - PPGINDE/NDAE/Tucuruí

URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/9400

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Agora exibindo 1 - 2 de 2

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)
Análise modal operacional: um estudo de caso da influência da alvenaria no comportamento dinâmico de prédios altos
(Universidade Federal do Pará, 2020-08-31) BORGES, João Pedro das Chagas; PRAZERES, Plínio Glauber Carvalho dos; http://lattes.cnpq.br/6175760351403329
Operational modal analysis consists on the modal parameters identification of a given structure from its normal operating conditions and is a reality in engineering applications, in line with the need for more precise and bold methods of structural monitoring. This dissertation aims to study and describe civil engineering structures operational modal analysis and, from its application, to study the masonry influence on the tall buildings dynamic behavior. In order to achieve the objective, two wellknown operational modal analysis methods were used as described in the text and it was showed that it is an important, viable and accurate tool for the Civil Engineering structures dynamic behavior identification. A sixteen-story building in the city of Belém-Pa was analyzed, before and after the masonry panels execution. Here consists the novelty in this work since it is very difficult to find building construction were the masonry is executed in the final construction stage only, what explain the lacking of studies with such characteristics. The study consisted on two measurement campaigns on four of the building's sixteen floors, with three points measure on each of these floors. The EFDD, in the frequency domain, and SSI, in the time domain, operational modal analysis methods were described and applied in the building modal identification in both campaigns. Satisfactory results were achieved and they were validated by the MAC coefficient. The identified natural frequencies had increases in a range from 25% to 35% in the masonry executed structure in relation to the reinforced concrete porch without masonry, which is structure's stiffness gain evidence. In addition, it was observed that this stiffness gain is considerably greater in one of the building's bending directions, indicated by a modal shapes inversion between the first two vibration modes when compared the two campaigns. Through these results, it was concluded that the masonry had significant interference in the building dynamic behavior.

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