Programa de Pós-Graduação em Engenharia de Infraestrutura e Desenvolvimento Energético - PPGINDE/NDAE/Tucuruí
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Item Acesso aberto (Open Access) Análise do comportamento de 3 pontes mistas em obras rodoviárias sujeitas à prova de carga estática(Universidade Federal do Pará, 2023-03-01) SILVA, Paulo Roberto Fontes da; PEREIRA FILHO, Manoel José Mangabeira; http://lattes.cnpq.br/4765401390604065; https://orcid.org/0000-0001-9622-3863; LIMA NETO, Aarão Ferreira; http://lattes.cnpq.br/0287664572311345; https://orcid.org/0000-0002-5911-1368Along the BR 230/PA, some bridges had their constructions interrupted about 20 years ago, and with the purpose of providing evaluation criteria to the works of road bridges with mixed structure in steel and concrete is proposed the methodology above. As acceptance criteria, static load tests were used in road bridges with mixed structure through characteristic tests, through instrumentation using strain gauges and LVDT's (Linear Variable Differential Transformer), defining displacements and deformations in the structural elements of the OAE (Special Artwork Bridge), with subsequent computational modeling of the structural model of the bridge, aiming to evaluate the performance of the bridges in service, as established in the structural modeling to the core of the OAE project, which were sized for a type train TB-45 (Type Vehicle of 450 kN of total weight),, according to NBR 7188 (2013). To monitor the displacements, LVDT's were used, positioned in the middle of the span and 1/4 of the span of the central stringers, as well as the strain gage allocated in the steel beams, brace and in the CA-50 steel bars of the pillars with verification of the deformations of the referenced structural parts. As results, an evaluation of the service conditions of the bridge was performed, compressing the experimental results of the static load tests with the theoretical-computational predictions in order to validate the models used, in general, the experimentally observed deformations were less intense than the theoretical estimates. This fact corroborates the agreement with the greater rigidity of the structural elements, validating the experimental results, because they presented behavior similar to the theoretical one, however in lower intensity of the OAE's studied. Thus, the experimental and theoric-computational results were compared with the international norms being the ratios of maximum displacement, residual displacement and deformation. The experimental response showed similar behavior, for the bridges over the Arataú, Anapú and Poraquê rivers, to the theoretically predicted. Inaddition to international norms, the results were divergent, especially in the Turkish, Spanish and German countries, and the boundary conditions imposed on the norms should be imposed.Item Acesso aberto (Open Access) Análise experimental do desempenho de conectores de cisalhamento de vergalhões dobrados para estruturas mistas via ensaios push-out(Universidade Federal do Pará, 2022-11-25) SOUSA, Vanessa Carolaine de; LIMA NETO, Aarão Ferreira; http://lattes.cnpq.br/0287664572311345; https://orcid.org/0000-0002-5911-1368Advances in civil engineering have led to the development of new techniques and materials that optimize the construction process. In this context, steel-concrete composite structures have emerged, which use steel and concrete efficiently through the collaborative work of the materials, exposing the metal part to tensile stresses and the concrete to compressive stresses. Shear connectors are essential in steel-concrete composite structures. They ensure the interaction between the materials and the transfer of stresses, making the structures lighter, stronger, and more durable. It is important to understand their operation and to seek new materials and technologies to optimize the structures. In this sense, this research continues the work of Souza (2019) and Barbosa (2016), who studied shear connectors made with CA-50 steel bars bent. The experimental program includes 7 models (varying the bar size, reinforcement rate, and the inclination of the connectors relative to the table of the metal profile) that were tested according to the recommendations of Eurocode 4 (2004). Of these 7 models, 2 were made with 12.5 mm rebar (models A1 and A2), 2 with 10.0 mm (models B1 and B2), 2 with 8.0 mm (models C1 and C2), and 1 model made with 6.3 mm diameter assembled in a single module (model D). When analyzing the load-carrying capacity/steel area ratio of the connectors, the results show that connector A1 (12.5 mm) had the best performance among the models in the study and also stands out when compared to other connectors studied such as those of Barbosa (2016), Souza (2019), and Chaves (2009). No significant evidence was observed that the inclination of the connectors positively affects the load-carrying capacity of the models. Analyzing the relative displacement between the profile and the slabs, it was possible to classify the models by ductility, in increasing order: D, A1, C1, C2, A2, B2, and B1. The 10.0 mm models have the highest ductilities, and the influence of the inclination of the connectors on this aspect is not clear. Analyzing the behavior in relation to uplift, it is noted that the best performances are in connectors B and C (10.0 mm and 8.0 mm) and there is a tendency for worse results in inclined connectors.Item Acesso aberto (Open Access) Análise experimental do desempenho de conectores de cisalhamento feitos em aço CA-50 para uso em estruturas mistas de perfis em aço e concreto armado(Universidade Federal do Pará, 2019-10-25) SOUZA, João Pedro Nascimento de; LIMA NETO, Aarão Ferreira; http://lattes.cnpq.br/0287664572311345; https://orcid.org/0000-0002-5911-1368The steel and concrete composite structures began to increase as a construction system over the years, due to their advantages both in their structural behavior and in their constructive aspects. These structures are those in which both materials (steel and concrete) work together, and for this to be possible, it is necessary to use connectors that combat the shear forces generated between the materials. There are several types of these connectors, but their goal is to make the structure solid and work monolithically. This work aims to experimentally analyze the performance of shear connectors, for use in steel and concrete reinforced composite structures, modifying geometries and arrangement of connectors composed of Ø 12.5 mm diameter CA50 steel bar bent in shape close to a truss, making a comparative to define which model offers the greatest contribution in the connection. Therefore, push-out tests were performed, following the procedure described in the European Standard Norm EN 1994-1-1 (2004), in 7 specimens, consisting of an 800 mm high welded I-metal profile, and two slabs of reinforced concrete, with dimensions of (600x600x150) mm, in contact with the top of flanges of the metallic profile, containing the welded connectors. Among the 7 models, 2 of them, named Isósceles Truss (IT) and Rectangular Truss (RT), were used as reference; in 4 of them were made variations on the arrangement of the connectors used on the reference specimens, which were named Slanted Isosceles Truss. (SIT), Slanted Rectangular Truss (SRT), Piramidal Isosceles Truss Type A (PIT A) and Piramidal Isosceles Truss Type B (PIT B), and in 1 was made a change on the geometry, which was named Straight Truss (ST). Regarding the load capacity, the ST connector presented a load gain of 10.82%, 32.94%, 19.53%, 34.51%, 30.98%, 23.14 % in relation to IT, RT, SIT, SRT, PIT A and PIT B, respectively. Taking into account the design resistance calculation (𝑃𝑅𝑑) of each connector according to EN 1994-11 (2004), the tested connectors had a load capacity 46.54% higher than 𝑃𝑅𝑑. The connectors, in their entirety, presented themselves as they are ductile in their breaking mode. Compared to the others, the RT connector presented a more rigid, and, the SRT, a more flexible behavior. Thus, it is observed that the proposed connectors presented a good performance in relation to the load capacity and rupture mode.Item 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/6175760351403329Operational 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.Item Acesso aberto (Open Access) Eletroquímica coloidal e sua relação com a sensibilidade de um solo argiloso na foz do rio Amazonas(Universidade Federal do Pará, 2023-06-29) SOUSA, Flaviany Luise Nogueira de; TEIXEIRA, Marcelo Rassy; http://lattes.cnpq.br/8912916360456192Clays have always played an important role in the history of civilizations, mainly because they are a mineral resource with varied technological applications. Among the several existing types, sensitive clays (quick clays), for example, are very complex soft soils that are considered real challenges for engineers due to the difficulty in obtaining their geotechnical parameters. In this sense, the aim of the present study was to analyze the sensitivity of a clay soil found in a region of the city of Santana, in the state of Amapá, Brazil. To this end, physical and chemical tests were carried out, including the SPT (Standard Penetration Test), X-Ray Diffraction (XRD), Zeta Potential (ζ), pH, Cation Exchange Capacity (CEC), as well as resistance assays (Vane Test and Fall Cone Test – FCT). The analyzed area is located in the Macapá Fluvio-marine Plain, which is composed of sediments that were deposited both by rivers and by the sea as a result of the region’s proximity to the mouth of the Amazon River. The geological profile obtained through geotechnical investigation indicated that the soil is constituted of mottled sandy-clay sediments, sandy-silty sediments with plant remains, and sandy- silty sediments with pebbles. As for the mineralogy of the samples, they were essentially composed of quartz and three clay minerals: kaolinite, mica/illite, and chlorite. Regarding sensitivity, all samples were classified as quick clays, with medium or high amounts of organic matter (O.M.); greater organic matter content was associated with increased sensitivity. In addition, it was understood that the intensity of clay sensitivity was higher with the increase in monovalent cations and the decrease in divalent cations such as Ca2+ and Mg2+, which must have been removed by the O.M. The soil pH reading ranged from high to very high acidity, an expected classification due to the increase in H+ concentration due to the O.M. All samples showed similar ζ values, with the lowest being 31.3 mV and 33.2 mV, which are still considered high, indicating that the soil colloids repel each other, forming a dispersed structure. Our results were consistent with similar reports in the literature; however, regionalized studies are necessary for a better understanding of the local peculiarities capable of influencing the profile of this soil.