Mestrado em Engenharia Civil

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http://repositorio.ufes.br/handle/10/17614

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Agora exibindo 1 - 5 de 294

Avaliação do ciclo de vida de concretos geopoliméricos : estudo comparativo
(Universidade Federal do Espírito Santo, 2024-06-24) Almeida, Rafael Saaid Meyrelles; Gama, João Luiz Calmon Nogueira da ; https://orcid.org/0000-0002-3054-4784; http://lattes.cnpq.br/; https://orcid.org/0009-0000-7423-9848; http://lattes.cnpq.br/; Pinho, Giusilene Costa de Souza ; https://orcid.org/0000-0002-4586-7092; http://lattes.cnpq.br/; Araújo, Georgia Serafim ; https://orcid.org/0000-0002-2029-6334; http://lattes.cnpq.br/
It is common knowledge that the construction industry is responsible for a significant portion of carbon dioxide emissions into the atmosphere. If the construction industry were a country, it would rank third among the world’s largest carbon dioxide emitters. The production of concrete, which is the second most used material in the world, is responsible for most of the greenhouse gas emissions from buildings. The aim of this research is to present an alternative with superior environmental performance to conventional concrete (CC), considering that the construction sector is very influential in the economic area, generating employment and income for various workers of different levels of qualification. To obtain a detailed and quantified diagnosis of the environmental impacts generated by the production of concrete, it is necessary to use Life Cycle Assessment (LCA), which is a holistic methodology that studies the environmental aspects and potential impacts, direct and indirect, throughout the life of a product. This study consists of conducting a comparative LCA between CC and Geopolymer Concretes (GC), which do not use cement in their composition, with their production in 5 concrete plants, located in the cities of Serra (ES), Porto Alegre (RS), Brasília (DF), Recife (PE) and Belém (PA). These cities were chosen to have a representation of all Brazilian regions: south, southeast, northeast, midwest and north. The GC demonstrated superior environmental performance to the CC in most of the evaluated
Estudo do comportamento mecânico de solos residuais de arenitos da Bacia Sedimentar do Paraná, para emprego em pavimentação ferroviária
(Universidade Federal do Espírito Santo, 2024-02-28) Cardoso, Lívia Mattedi; Pires, Patricio José Moreira ; https://orcid.org/; http://lattes.cnpq.br/; https://orcid.org/; http://lattes.cnpq.br/; Teixeira, Jamilla Emi Sudo Lutif ; https://orcid.org/; http://lattes.cnpq.br/; Ribeiro, Wagner Nahas ; https://orcid.org/; http://lattes.cnpq.br/
Soils and aggregates are the main materials used in paving activities. Therefore, it is important to study the materials available in the project implementation region to economize on costs related to material transportation and the exploitation of new quarries. The selection of materials to compose the layers of railway pavement, according to current normative recommendations, is still based on traditional classification criteria, such as the California Bearing Ratio (CBR), which does not reflect the reality of Brazilian conditions, as it was conceived from the study of temperate climate soils. Tropical soils, typical of Brazil, undergo a weathering process that provides notable properties from a pavement engineering perspective, highlighted by their satisfactory mechanical resistance and low expansibility. The mechanistic approach to pavement design allows for a detailed analysis of the mechanical behavior of each layer of the pavement structure, enabling the assessment of stress and strain states based on Resilient Modulus values. However, due to the significant geotechnical variability of Brazilian soils, obtaining this parameter through specific laboratory tests is limited by cost issues, often necessitating the use of simpler and more economical tests, such as physical characterization tests. Since the use of traditional classification criteria can result in the constant rejection of materials that would be suitable from a mechanistic standpoint, a better understanding of the mechanical behavior of these soils is necessary. Thus, this study aims to analyze the resilient behavior of tropical soils to develop a predictive model for the Resilient Modulus from physical characterization tests, such as grain size distribution, consistency limits, and compaction. The relevance of this effort is highlighted by the high cost of tests to obtain the Resilient Modulus, justifying the need to seek correlations to estimate it, especially during the preliminary design phase, aiming to optimize costs and resources. Additionally, this work explores the possibility of using materials that, although not meeting the criteria of current traditional classifications, still present mechanical qualities suitable for application in railway pavements. To achieve the proposed objectives, 74 physical characterization tests, Resilient Modulus tests, and classification tests of tropical soils were analyzed in samples collected in the municipality of São José do Rio Preto – SP, belonging to the geological unit of the Paraná Sedimentary Basin. The results of the statistical analyses indicated good adherence between the Resilient Modulus tests and the physical characterization of lateritic soils
Otimização de estruturas treliçadas considerando análise não linear e carregamento dinâmico
(Universidade Federal do Espírito Santo, 2024-05-03) Domingues, Bárbara Scardini; Rodrigues, Marcos Antonio Campos ; https://orcid.org/0000-0003-2084-5820; http://lattes.cnpq.br/6963345955441105; Alves, Élcio Cassimiro ; https://orcid.org/0000-0001-6971-2645; http://lattes.cnpq.br/6509450210637509; https://orcid.org/0000-0001-9803-736X; http://lattes.cnpq.br/1812214517235259; Dias, João Victor Fragoso ; https://orcid.org/0000-0003-1455-1519; http://lattes.cnpq.br/0090215976146284; Medeiros, Guilherme Fleith de ; https://orcid.org/0000-0003-0252-824X; http://lattes.cnpq.br/0811357090167648
Structural optimization techniques help designers to develop economical projects more efficiently, in addition to automating the design process. Some large-scale truss structures may present dynamic loading, large displacements, and material plastification, requiring a nonlinear analysis. Therefore, this work aims to optimize truss structures considering geometric and material nonlinear behavior when subjected to dynamic loading. Thus, it was necessary to determine the cross-sectional area of the bars that minimizes the total mass of the structure, imposing constraints on nodal displacements, axial stresses, and axial compression force. For the optimization problem, a computational program was developed on the Matlab platform using Particle Swarm Optimization (PSO) and the Genetic Algorithm (GA), a native Matlab tool to verify the results. The geometric and material nonlinear dynamic analysis procedure was performed using the Ansys software, with the Newmark method coupled with the Newton-Raphson method. Examples of plane and spatial trusses subjected to different types of dynamic loading were solved using the developed computational program and validated by comparison with solutions present in the literature. The results indicated that the effect of nonlinearities on the optimized structures is particular to each case, PSO was the algorithm that shown best performance and robustness and the damping effect led to a reduction in the final mass
Uso de redes neurais artificiais e análises de regressão para avaliar correlações entre resultados de ensaios de penetração de campo
(Universidade Federal do Espírito Santo, 2024-03-25) Carias, Gabriele Carvalho Bahiense; Hisatugu, Wilian Hiroshi ; https://orcid.org/0000-0001-8333-0539; http://lattes.cnpq.br/6597878238749014; Bicalho, Kátia Vanessa ; https://orcid.org/0000-0002-2157-7322; http://lattes.cnpq.br/9639299365620025; https://orcid.org/0009-0002-8803-6165; http://lattes.cnpq.br/4423444667443490; Silva, Maristela Gomes da ; https://orcid.org/0000-0002-7104-1972; http://lattes.cnpq.br/4450263733589061; Danziger, Bernadete Ragoni ; https://orcid.org/0000-0001-8413-1240; http://lattes.cnpq.br/2006272256799450; Giacheti, Heraldo Luiz ; https://orcid.org/0000-0001-7999-0956; http://lattes.cnpq.br/0781618586438933
The results of field tests for determining soil resistance to penetration are essential for defining geotechnical behavior and estimating parameters in civil engineering projects. Due to the variety of tests and the impossibility of complete investigations, it is necessary to evaluate correlations between different tests, considering their specific characteristics. This research analyzed the influences on the correlations defined between the results of SPT and CPT (and their variations, such as piezocone penetration test, CPTu) soil resistance determination tests, and examined the use of artificial neural networks to correlate field test results for determining soil resistance to penetration. A statistical pre-treatment of the data was performed, evaluating the frequency distribution of the different analyzed parameters and their ranges of variation. The study also discussed the benefits obtained by considering the results of DMT tests associated with CPTu and SPT tests for identifying soil mechanical behavior, highlighting interpretation divergences when considering the three in-situ tests. Additionally, the influence of parameters such as depth, lateral friction, excess pore pressure, among others, on the correlations defined between the SPT and CPTu soil resistance determination test results was evaluated. An artificial neural network (ANN) model of the multilayer perceptron (MLP) type was developed to correlate in-situ penetration test results. The data used in this research consisted of 38355 sets of SPT-CPT-DMT results for sandy, silty, and clayey soils. The input variables of the ANN model include: SPT N60 penetration resistance index, cone tip resistance (qt), lateral friction (fs), pore pressure (u2), and material index (Ic) from the CPTu, as well as the material index (ID) from the DMT. The research demonstrates that factors such as depth and lateral friction influence the SPT-CPTu relationships, and neural networks trained only with qt and N60 showed low performance. However, the inclusion of depth, lateral friction, and the DMT ID improved the statistical performance of the model, which, nevertheless, does not fit a generic equation
Avaliação do coproduto siderúrgico KR como estabilizador para diferentes tipos de solo
(Universidade Federal do Espírito Santo, 2024-03-28) Fardin, Henrique Delboni; Gomes, Guilherme José Cunha ; https://orcid.org/0000-0001-9510-4600; http://lattes.cnpq.br/1437609255681568 ; Pires, Patrício José Moreira ; https://orcid.org/0000-0001-5445-1753 ; http://lattes.cnpq.br/0913529658589507 ; https://orcid.org/0009-0005-5351-6021 ; http://lattes.cnpq.br/7146116210406485 ; Ribeiro, Wagner Nahas; https://orcid.org/0000-0002-4130-9093 ; http://lattes.cnpq.br/1143022421703767 ; Alledi, Carla Therezinha Dalvi Borjaille ; https://orcid.org/0000-0002-8429-731X ; http://lattes.cnpq.br/4542859765962073
Brazilian road transport sector is responsible for 65% of freight transportation and faces challenges, with only 12.4% of its road network paved. The research highlights the shortage of materials for paving, driving the study of the steel co-product KR (CP KR) as a soil stabilizer. As this residue demonstrates technical and environmental feasibility for use in pavements, the aim of the work was to evaluate the performance of the steel co-product type KR as a soil stabilizer for paving. Laboratory tests were conducted to evaluate the physical, mechanical, and mechanistic parameters of soils with different percentages of fines and related to results obtained by other authors. The study on CP-KR for paving revealed its potential in modifying the physical indices of soils and increasing mechanical strength. The greatest increases in strength occur in soils with 55% fines, while the Resilient Modulus increased more in less clayey soils, reaching a strength increase of 275%. The soils showed a significant reduction in plastic deformation, with an average decrease of 72%. The results demonstrated the potential of CP-KR as a soil stabilizer for the composition of road pavements

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