https://repositorio.ufba.br/handle/ri/22486 Mon, 04 May 2026 11:46:09 GMT 2026-05-04T11:46:09Z https://repositorio.ufba.br/handle/ri/44434 Título: Avaliação das propriedades físico-mecânicas e reológicas de compósitos de cimento de fosfato de magnésio com adição de fibras de aço, de sisal (agave sisalana) e de pva Autor(es): Lima, Danilo Carvalho de Primeiro Orientador: Ribeiro, Daniel Véras Abstract: Magnesium phosphate cement (MPC) is an acid-base binder with superior physical mechanical properties compared to conventional hydraulic cements, yet it still presents many gaps, aiming at its development and wider application. This study evaluates the physical, mechanical, and rheological performance of MPC composites reinforced with PVA, sisal, and steel fibers in different proportions, aiming to reduce the brittleness and low deformability of the cementitious matrix. The MPC raw materials (calcined MgO, ammonium dihydrogen monophosphate - ADP, sodium tripolyphosphate – STP, and boric acid), sand, and steel (metallic), polymeric (PVA), and sisal (vegetable) fibers were characterized in terms of physical, chemical, and mineralogical aspects to optimize the formulation and allow evaluations of the composites in the fresh and hardened states. In the fresh state, setting time, pH, calorimetry, and rheological analysis tests were performed on the reference matrix and samples with different fiber contents. After molding and curing, the samples were subjected to phase formation analysis by XRD and thermogravimetry (TG/DTA), in addition to physical-mechanical analysis (specific mass, apparent porosity, capillary absorption, dimensional stability, axial compressive strength, and flexural tensile strength). The results showed that the addition of steel fibers to the CFM promoted significant gains in flexural tensile strength and compressive strength, with emphasis on the increase in toughness, evaluated by the I10 factor, indicating a more ductile post-cracking behavior and an efficient redistribution of stresses. While the addition of natural fibers to the composites resulted in a loss of mechanical performance, contributing to reduced strength values and increased variability in results, possibly due to high water absorption and low interfacial adhesion with the matrix, the chemical acetylation treatment showed promise in improving the mechanical properties of CFM composites with sisal fibers. The insertion of PVA fibers into the CFM matrix provided a modest improvement in mechanical strength compared to the reference matrix and superior performance to that of composites containing natural sisal fibers. Editora / Evento / Instituição: UNIVERSIDADE FEDERAL DA BAHIA Tipo: Dissertação Tue, 03 Mar 2026 00:00:00 GMT https://repositorio.ufba.br/handle/ri/44434 2026-03-03T00:00:00Z https://repositorio.ufba.br/handle/ri/44431 Título: Avaliação em massa de imóveis urbanos através de modelagem de regressão espacial Autor(es): Gonçalves, Waltério de Oliveira Primeiro Orientador: Alixandrini Junior, Mauro José Abstract: With the increasing demand for efficiency in municipal revenue collection, real estate appraisal has gained even more relevance due to the fundamental role of the Property and Territorial Urban Tax (IPTU). Since the implementation of Complementary Law No. 101 of May 4, 2000, known as the Fiscal Responsibility Law (LRF), municipalities have faced an urgent need for more robust methods to calculate the market value of properties, driven by the pursuit of tax equity. Detailed and precise planning is essential to ensure that the values assigned to properties fairly reflect their characteristics and location. This study modeled parameters for the appraisal of urban properties, promoting fair proportionality in the generation of Generic Value Maps (PVG). The research was conducted in Camaçari, a municipality in the Metropolitan Region of Salvador (BA), which has over 300,000 inhabitants and stands out as one of Brazil's main industrial hubs, hosting the Camaçari Industrial Pole. The study covered areas in the neighborhoods of Arembepe, Barra de Jacuípe, Boa Esperança, Genipabu, and Vale do Landirana, using a sample of 124 land plots for modeling and 12 for validation. The methodology compared the Ordinary Least Squares (OLS) regression with the global spatial model Conditional Auto Regressive (CAR) and the local Geographically Weighted Regression (GWR) model. The models were evaluated based on quality indicators such as the Akaike Information Criterion (AIC), Log Likelihood (LIK), coefficient of determination ($R^2$), and Root Mean Square Error (RMSE), in addition to specific metrics for mass appraisal, such as Median Ratio (Med R), Coefficient of Dispersion (COD), and Price Related Differential (PRD), according to the International Association of Assessing Officers (IAAO) criteria. The results indicated that GWR was able to significantly reduce spatial effects, outperforming the other models in most quality and performance criteria. The methodology was combined with Ordinary Kriging to generate unit value surfaces. The semivariogram adjusted to the Gaussian model allowed the kriging of predicted values, and the surface generated by the GWR predicted values achieved the lowest RMSE and better performance indicators, close to the limits recommended by the IAAO. It is concluded that GWR modeling was the most effective in representing spatial variations in real estate values in the studied area, and the proposed methodology for PVG generation demonstrated great potential for application by municipalities in the mass appraisal of urban properties, contributing to fairer and more precise tax collection, especially for taxes such as IPTU and the Real Estate Transfer Tax (ITBI). Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Dissertação Fri, 28 Mar 2025 00:00:00 GMT https://repositorio.ufba.br/handle/ri/44431 2025-03-28T00:00:00Z https://repositorio.ufba.br/handle/ri/44098 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 Wed, 04 Feb 2026 00:00:00 GMT https://repositorio.ufba.br/handle/ri/44098 2026-02-04T00:00:00Z https://repositorio.ufba.br/handle/ri/44070 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 Sun, 01 Sep 0009 00:00:00 GMT https://repositorio.ufba.br/handle/ri/44070 0009-09-01T00:00:00Z