https://repositorio.ufba.br/handle/ri/22486 2026-04-17T03:24:32Z 2026-04-17T03:24:32Z Lima, Vinícius de Sousa https://repositorio.ufba.br/handle/ri/44098 2026-02-25T19:27:34Z 2026-02-04T00:00:00Z

Título: Análise do reforço com fibras de carbono no comportamento mecânico de vigas de LVL de madeira de paricá coladas com resina de poliuretano à base de óleo de mamona Autor(es): Lima, Vinícius de Sousa Primeiro Orientador: César, Sandro Fábio Abstract: Paricá, a native Amazonian species and one of the pioneers in planted forest cultivation, is characterized by rapid growth, good workability, and low density. However, due to its low mechanical strength class (D20), the use of this wood species in structural elements of civil construction is limited. An alternative to overcome this limitation is its industrial processing into laminated veneer lumber (LVL) incorporating carbon fiber reinforcement. Among synthetic fibers, carbon fibers stand out due to their high elastic modulus and tensile strength, low density, high thermal stability, and good thermal and electrical conductivity. In this context, the present study aimed to evaluate the influence of unidirectional carbon fiber fabric reinforcement on the mechanical behavior of LVL beams manufactured from paricá veneers bonded with castor oil-based polyurethane, with the goal of improving the material’s mechanical properties and expanding its potential for structural applications. To this end, four series of elements were produced under laboratory conditions: solid sawn timber beams; unreinforced LVL beams; LVL beams reinforced with one layer of carbon fiber fabric; and LVL beams reinforced with two layers of carbon fiber fabric. In the reinforced series, the reinforcement was placed between the outermost and penultimate veneers on the tension side of the beams. The mechanical behavior of the beams was assessed through four-point bending tests, with the determination of maximum bending moment, global stiffness, ductility, and failure modes. Maximum bending moment and global stiffness were estimated using both analytical (transformed section method) and numerical (finite element method) approaches. Additionally, to assess the influence of reinforcement on the bond quality provided by the adhesive, shear tests at the glue line were conducted. The results showed that reinforcement with two layers of carbon fiber fabric led to significant increases in load-carrying capacity (27.16%) and stiffness (29.98%) of the LVL beams compared to unreinforced elements. In contrast, the application of only one layer resulted in limited gains in maximum bending moment, with no statistical significance, and was insufficient to increase the global stiffness of the beams. Moreover, compared to unreinforced elements, the use of reinforcement altered the failure modes from brittle to ductile, increasing ductility indices by up to 137.37% (for LVL reinforced with two layers), which may indicate enhanced structural safety. Both theoretical approaches proved effective in estimating the mechanical properties of the series, with the numerical method showing greater agreement with the experimental results when compared to the analytical method. In addition, the failure modes observed in the numerical model adequately represented those observed experimentally. The presence of reinforcement did not affect the bond quality provided by the polyurethane adhesive. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Dissertação

2026-02-04T00:00:00Z Sena, Rafael Oliveira https://repositorio.ufba.br/handle/ri/44070 2026-02-24T16:34:17Z 0009-09-01T00:00:00Z

Título: Método para integração de imagens coletadas por drone ao modelo BIM para apoio à gestão da manutenção de fachadas Autor(es): Sena, Rafael Oliveira Primeiro Orientador: Costa, Dayana Bastos Abstract: Poor maintenance of facades poses risks to building performance, as this system serves as a protective interface with the surrounding environment. Therefore, periodic preventive inspections and maintenance are necessary to prevent or correct pathological manifestations at early stages. The lack of maintenance in Brazilian public buildings is highly sensitive, reinforcing the need for solutions that add efficiency to building management systems, which are characterized mainly by low levels of digitalization. This study aims to propose guidelines for integrating visual assets collected by drones in façade inspections with Building Information Modeling (BIM) to support maintenance management in buildings with low digital maturity. The research approach adopted is Design Science Research (DSR), following these steps: 1) Problem awareness – drone inspection and interviews with managers of a public university building to understand the current maintenance management structure, and a systematic literature review to identify scientific gaps and deepen theoretical foundations; 2) Artifact suggestion – inspection of façades of ten institutional buildings and interviews with professionals from the institution’s maintenance sector to identify existing anomalies and perceptions of the current scenario of the maintenance department, as well as identification of requirements and limitations of the photogrammetry process and analysis of anomalies; 3) Artifact development – practical application of the method in one institutional building to define protocols for handling visual assets and integrating anomaly information into the building’s BIM model; 4) Artifact evaluation – through the constructs “perceived ease of use,” “utility,” “impact potential,” and “transparency”; and 5) Conclusion – analyzing the alignment of the artifact with the established context to formalize the method. The main outputs were five protocols aimed at: 1) drone image acquisition for maintenance purposes; 2) photogrammetric processing; 3) analysis of informational requirements of the BIM model; 4) integration of orthomosaics into the façade models; and 5) data integration and availability of inspection records. The results evidenced the potential of the method for the institutional context, validated by maintenance department professionals, and indicated clarity in executing the steps and in making the results available, characterizing it as transparent and capable of centralizing building information. The main limitations include dependence on operational skills, which influence product quality, and the restriction of the method to visual analyses due to the exclusive use of drones for data collection. Overall, the findings indicate that the method constitutes a practical and replicable solution for integrating visual assets into BIM, contributing to overcoming limitations reported in the literature and supporting improvements in building maintenance management. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Dissertação

0009-09-01T00:00:00Z Martins, Matheus Gomes https://repositorio.ufba.br/handle/ri/43633 2025-12-09T16:13:51Z 2025-07-25T00:00:00Z

Título: Protótipo de contrato inteligente com blockchain e BIM na execução de obras: uma aplicação na concretagem de paredes moldadas in loco Autor(es): Martins, Matheus Gomes Primeiro Orientador: Melo, Reymard Savio Sampaio de Abstract: The concrete supply chain in the construction industry still relies on analog processes that hinder traceability, compromise transaction reliability, and lead to conflicts between contractors and suppliers. These challenges are especially critical in cast-in-place systems, where the control over concrete delivery, receipt, and payment is fragmented. This study proposes a smart contract prototype, named BIMLedger, which integrates blockchain technology, smart contracts, and Building Information Modeling (BIM) with the goal of optimizing the payment flow for cast-in-place concrete wall systems. The research adopts the Design Science Research (DSR) approach, structured in the following stages: (i) Awareness, through a Systematic Literature Review (SLR) on current gaps in automated payment models; (ii) Suggestion, by means of an exploratory study conducted on a real construction project; (iii) Development, involving process modeling in a second project, including delivery receipt, verification, and validation flows supported by BIM; (iv) Evaluation, through experimental testing of the smart contract in a simulation environment and qualitative assessment via semi-structured interviews; and (v) Conclusion, presenting proposals for scalability and broader application of the prototype. The main outcomes include a Relational Entity Model (REM), an Entity-Relationship Diagram (ERD), BIM models derived from the building, business flowcharts and the BIMLedger prototype itself. It is concluded that BIMLedger is a viable solution for the digital transformation of payment flows in the construction sector, with the potential to reduce disputes, accelerate payments, and strengthen contractual governance. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Dissertação

2025-07-25T00:00:00Z Batista, Vital Matos https://repositorio.ufba.br/handle/ri/42824 2025-09-05T16:28:44Z 2025-03-21T00:00:00Z

Título: Análise da anisotropia de areias reforçadas com fibras naturais e sintéticas Autor(es): Batista, Vital Matos Primeiro Orientador: Machado, Sandro Lemos Abstract: During the execution of earthworks, suitable soil deposits with the required strength and compressibility characteristics are not always available, making it necessary to search for soils in more distant locations or to adopt stabilization methods that adjust their properties to meet the needs of the project. The use of fiber-reinforced soils in Civil Engineering has shown promising results in the construction of embankments, dams, and earth structures. However, despite the research already carried out on this topic, there is a lack of focus on the anisotropy generated during the field compaction process, which produces a sub-horizontal alignment of the fibers. In light of this, this work presents and analyzes results from laboratory tests performed on composites made with two different sands (river sand and dune sand) and two types of fibers (coconut and polypropylene) in which the failure plane forms different orientations with the preferential orientation of the fibers, as in the case of triaxial compression and extension tests and direct shear tests. Results from previous studies carried out at GEOAMB supported this research and were used alongside data produced by the author. In the triaxial extension tests, the predominant effect of low confining stresses was observed, which, when associated with the use of the Mohr-Coulomb model (which assumes material isotropy), resulted in artificially high strength parameters, contrary to the expectations of reduced strength due to the unfavorable fiber orientation relative to the failure plane. Regarding volumetric deformation, polypropylene fibers proved more effective than coconut fibers in reducing dilatancy in the river and dune sand matrices in both triaxial compression and direct shear tests. In the triaxial extension tests, however, the use of both fibers led to a trend of increased volumetric expansion, although this trend was less pronounced for the polypropylene fibers. River sand, which has sub-angular particle shapes and a better grain size distribution than dune sand, showed more pronounced dilative behavior in the cases analyzed. Graphs relating cohesive gain to the angle between fiber orientation and the failure plane indicate that coconut fibers induce less anisotropy compared to polypropylene. Finally, computed tomography image tests and visual observations of fiber predisposition in failed samples confirm their tendency toward sub-horizontal alignment after sample compaction. Furthermore, it was noted that although both fibers tend to sub-horizontalize (supporting the hypothesis that the compaction process induces a preferential fiber orientation in the composite that directly affects its mechanical performance), coconut fibers tend to disperse and mix better in the sand matrix, while polypropylene fibers tend to agglomerate in some regions, which helps explain the less anisotropic behavior found in composites reinforced with coconut fiber. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Dissertação

2025-03-21T00:00:00Z