Mestrado em Engenharia Civil

URI Permanente para esta coleção

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

Nível: Mestrado Acadêmico
Ano de início:
Conceito atual na CAPES:
Ato normativo:
Periodicidade de seleção:
Área(s) de concentração:
Url do curso:

Navegar

Agora exibindo 1 - 5 de 317

Modelos para verificação de flecha de vigas de concreto protendido
(Universidade Federal do Espírito Santo, 2026-03-30) Cruz, Lucas Sena da; Luchi, Lorenzo Augusto Ruschi e; Laure, Elisabeth Junges; https://orcid.org/0000-0002-9094-2645; http://lattes.cnpq.br/4385254860391051; Rodrigues, Marcos Antônio Campos; Trautwein, Leandro Mouta
This study aimed to implement and evaluate models for calculating the deflections of prestressed concrete beams by incorporating procedures based on ABNT NBR 6118 and the fib Model Code into the AVSer computational program, including both simplified and refined formulations. The implemented procedures were validated against results available in the technical literature and applied to a parametric study of simply supported beams with different prestressing levels, cross-sectional geometries (rectangular and T-shaped), and bonded and unbonded prestressing systems. The results showed that the refined ABNT NBR 6118 model provided the most stable deflection predictions, whereas the fib Model Code yielded more conservative estimates, while the simplified ABNT NBR 6118 method presented intermediate behavior. It was also found that T-shaped sections reduce deflections compared with rectangular sections, that the bonding condition of the prestressing tendons has little influence on the final deflection values, and that, for the cases analyzed, partially prestressed beams may not satisfy serviceability deflection limits when the prestressing force balances less than approximately 64% of the applied bending moment for rectangular sections and 74% for T shaped sections. Finally, the developed tool proved to be suitable for automating the calculation of deflections in prestressed concrete beams, enabling the systematic comparison of different analytical approaches.
Desenvolvimento de ferramenta computacional considerando o efeito de membrana na verificação estrutural de lajes mistas em situação de incêndio
(Universidade Federal do Espírito Santo, 2026-03-17) Pereira, Isabele Sales; Azevedo, Macksuel Soares de; https://orcid.org/0000-0003-3011-3420; http://lattes.cnpq.br/6726295161401220; Ferreira, Walnório Graça; https://orcid.org/0000-0002-2079-6048; http://lattes.cnpq.br/9453786966994911; Izoton, Gabriela Pereira Lubke; http://lattes.cnpq.br/1689020218928246
Studies on fires, both related to firefighting and to the load-bearing capacity of structures, have increased in recent years due to economic losses and fatalities. This work aims to develop a computational program for the design of composite slabs subjected to high temperatures considering the membrane effect, using symmetric and asymmetric welded mesh reinforcement. ABNT NBR 14323:2013 provides guidelines for the design of these structures by neglecting the contribution of the steel deck in its calculations and, consequently, requires the use of positive reinforcement; however, it does not account for the impact of the amplification coefficient caused by the membrane effect on the load-bearing capacity of the slab, thus making the design very conservative and uneconomical. The methodology consists of applying the method developed by Bailey (2001), which considers the membrane effect in slabs subjected to elevated temperatures. Results from the program developed in this research were analyzed using temperatures obtained from thermal analysis, as well as through the use of the computational program MACS+ for slab analysis with symmetric and asymmetric welded meshes. The results proved to be conservative when compared to the temperatures from EN 1994-1 2:2014, while the reinforcement ratio showed a particularly significant influence on the results. For meshes with smaller steel areas, a more uniform trend of increasing load-bearing capacity with increasing slab thickness was observed
Autocicatrização de concretos com aditivos cristalizantes e materiais cimentícios suplementares: análise da migração de cloretos e da evolução microestrutural
(Universidade Federal do Espírito Santo, 2025-10-30) Barreto, Leonnardo Postinghel; Vieira, Geilma Lima ; https://orcid.org/0000-0001-6148-3307; https://lattes.cnpq.br/5783172236615493; Bonsembiante, Francieli Tiecher; https://orcid.org/0000-0002-5411-9299; https://lattes.cnpq.br/4120356383320275; Pilar, Ronaldo ; https://orcid.org/0000-0002-1906-2071; https://lattes.cnpq.br/6669573444640365
Reinforced concrete structures are prone to cracking, which facilitates the ingress of aggressive agents, especially chloride ions, thereby reducing durability. This study aimed to evaluate the self-healing phenomenon in concretes containing silica fume, blast furnace slag, fly ash, a crystalline admixture, and a reference concrete. To quantify chloride ion permeability, the electrical migration test according to ASTM C1202 (2022) was employed. Additionally, qualitative analyses were conducted through stereoscopic optical microscopy, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), in order to identify and characterize the healing products. The statistical analysis of the results allowed the classification of the specimens according to ASTM C1202. Concretes with slag and silica fume showed the lowest charge passed values, demonstrating better performance against chloride ion penetration. In contrast, the reference concrete and the crystalline admixture presented higher charge passed values. Microstructural characterization confirmed the presence of hydration products and precipitates associated with crack closure and reduced charge passed, particularly in concretes with slag and silica fume. EDS analyses revealed substantial differences in the products formed inside cracks after self-healing. The pozzolanic effect proved highly effective through the formation of secondary C–S–H, while CaCO₃ in calcite form was observed in all mixtures with different morphologies. Magnesium was also detected, mainly in concretes with higher levels of free calcium hydroxide
Durabilidade de concretos com incorporação de escória de Ferroníquel como material cimentício suplementar : migração de íons cloreto, carbonatação e análise microestrutural
(Universidade Federal do Espírito Santo, 2026-02-26) Quinquim, Thiago Almeida; Sakata, Rafael Dors; https://orcid.org/0000-0002-7022-3846; https://lattes.cnpq.br/3547547454752538; Pilar, Ronaldo; https://orcid.org/0000-0002-1906-2071; https://lattes.cnpq.br/6669573444640365; Vieira, Geilma Lima; https://orcid.org/0000-0001-6148-3307; https://lattes.cnpq.br/5783172236615493; Araújo, Geórgia Serafim; https://orcid.org/0000-0002-2029-6334; https://lattes.cnpq.br/4707150428037806; Medeiros, Marcelo Henrique Farias de; https://orcid.org/0000-0003-3112-9715; https://lattes.cnpq.br/2049752365695485
Partial replacement of Portland cement with supplementary cementitious materials (SCMs) is a consistent strategy to enhance the sustainability of the construction sector by reducing the clinker factor and its environmental impacts, especially when these materials are regionally available. This study investigated the technical feasibility of incorporating ground ferronickel slag (FNS) as an SCM in concrete, evaluating mechanical performance, durability indicators, and microstructural evidence. The mixtures were produced with a constant water-to-binder ratio and different replacement levels (including a reference mixture and a composition with inert limestone filler). Performance was assessed through compressive strength, chloride transport tests (passed charge and migration coefficient), electrical resistivity, volume of permeable voids, and accelerated carbonation. The interpretation of the results was supported at the microstructural level by synchrotron X-ray diffraction with quantitative refinement and thermogravimetric analysis, enabling relationships between composition/mineralogy and hydration evolution to be established. FNS, characterized by a low Ca/Si ratio and a considerable siliceous amorphous fraction, exhibited predominantly late pozzolanic reactivity, consuming Ca(OH)2 and forming additional C–S–H, which promoted matrix densification. At later ages, a consistent reduction in ionic transport and volume of permeable voids were observed, accompanied by increased electrical resistivity, indicating greater resistance to chloride ingress. However, high replacement levels increased vulnerability to carbonation, mainly at early ages, attributed to clinker dilution and reduced alkaline reserve, although late age densification partially mitigated this effect. Overall, replacement levels around 30% provided the best balance between mechanical performance, durability gains, and carbonation resistance.
Análise de pilares mistos retangulares preenchidos submetidos à flexo-compressão : proposição de equações e ferramenta computacional
(Universidade Federal do Espírito Santo, 2025-12-09) Miranda, Glaubert Araujo; Ferreira, Walnório Graça ; https://orcid.org/0000-0002-2079-6048; https://lattes.cnpq.br/9453786966994911; Calenzani, Adenilcia Fernanda Grobério ; https://orcid.org/0000-0002-0936-9950; https://lattes.cnpq.br/9959808218883879; Oliveira, Romilde Almeida de ; https://orcid.org/0000-0002-6786-9080; https://lattes.cnpq.br/9272579827887449; Rossi, Alexandre ; https://orcid.org/0000-0001-9590-1554; https://lattes.cnpq.br/3946998323160911
Contemporary construction increasingly demands structural designs employing slender columns, aiming to optimize architectural space and reduce material consumption while maintaining safety and structural efficiency. Among the available solutions, composite columns with concrete-filled rectangular sections stand out as an efficient and economical alternative, especially when combined with high-strength steel and concrete. The design of these columns is based on the provisions of ABNT NBR 8800:2024, which presents simplified models for the flexural–compression verification of compact, semicompact, and slender sections. However, the standard does not provide expressions for determining the neutral axis position in semicompact and slender sections, nor for calculating the moments corresponding to the onset of compressive plastification in semicompact sections or the initiation of yielding in the tension flange of slender sections, which limits its practical application. In this study, a computational tool was developed in MATLAB for verifying concrete-filled rectangular composite columns subjected to flexural–compression, based on the design models of ABNT NBR 8800:2024. As a central contribution of the research, mathematical formulations are proposed to determine the neutral axis position and the moments associated with the initial stages of plastification and yielding in semicompact and slender sections, respectively. The tool enables automated generation of M–N interaction curves, facilitating the analysis of the structural behavior of these columns and helping to address existing gaps in the standard. To assess the adherence of normative methods to actual behavior, 37 experimental tests of rectangular concrete-filled steel tube columns reported in the literature were processed using the developed tool and evaluated according to ABNT NBR 8800:2024 and AISC 360-22. The results showed that, for compact sections, Model II of ABNT NBR 8800:2024 provided the best estimates, with mean ratios of normalized-to-ultimate moments (!!"#$%/!&,) ranging from 0.80 to 0.87. For semicompact and slender sections, Model III of ABNT NBR 8800:2024 and Method IV of AISC 360-22 yielded the most consistent—though conservative—predictions, highlighting the increase in conservatism of these models as both the sectional slenderness and steel strength increase

Navegar

Submissões Recentes