Teses em Engenharia Civil (Doutorado) - PPGEC/ITEC

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/9887

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Aplicação de madeiras amazônicas em elementos de madeira lamelada colada (MLC)
(Universidade Federal do Pará, 2023-03-16) NEVES, Paulo Henrique Lobo; MOUTINHO, Victor Hugo Pereira; http://lattes.cnpq.br/8464600937488553; MACEDO, Alcebíades Negrão; http://lattes.cnpq.br/8313864897400179
Timber is considered on the world stage as the primary building material of the 21st century. However, for this potential to be actualized, technologies for unfolding and using the raw material, such as Glued Laminated Timber (glulam), need to be disseminated and used in a wider range of species. In this regard, we emphasize that, despite the great existing diversity, only some studies are found to verify the potential use of Amazonian timber in glulam. This way, this paper aims to analyze the gluing of ten species native to the Amazon, namely: Jacaranda sp., Simarouba amara Aubl., Astronomium lecointei, Couratari sp., Cedrela fissilis., Cordia Goeldiana Huber, Hymenaea courbaril., Dipteryx odorata. Euxylophora paraensis., Mezilaurus itauba., and the combination with four different types of adhesives, two structural resistant to moisture and two non-structural, using a shear sample of solid timber as a evidence, with a minimum of 20 repetitions per treatment. Complementary tests such as delamination and static bending were carried out. We verified that for some species there was an adhesive with statistically equal and superior resistance in some combinations compared to the control sample, demonstrating that the studied species have the potential for the production of glulam, as well as for other products that use adhesives.
Acesso aberto (Open Access)
Avaliação de modelos de inteligência artificial híbridos na estimativa de precipitações
(Universidade Federal do Pará, 2022-03-18) GOMES, Evanice Pinheiro; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
The hydrological analyzes carried out from rainfall in the Amazon are essential due to its importance in climate regulation, regional and global atmospheric circulation. However, in this region, there are limitations related to data series with short periods and many flaws, especially in the daily scale. Despite significant advances in science and technology, practical and accurate predictions have been a major concern due to their complexity. Therefore, several conceptual models, empirical or hybrid, have been tested to forecast rain with greater precision. Among empirical models, those that incorporate artificial intelligence (AI) methods are potentially useful approaches to simulate the precipitation process. Artificial Neural Networks (ANN), as AI models, are able to establish a relationship between historical inputs (rain, flow, etc.) and the desired outputs, through a non-linear function composed of several factors that are adjusted to the observed data, allowing your prediction. Thus, to improve the precipitation analysis, hybrid models were developed, involving Artificial Neural Network (ANN) of the type with Time Delay (TDNN), ELMAN network, Radial Base network (RBF) and Adaptive Neuro-Fuzzy Inference System (ANFIS), coupled with Maximum Overlap Discrete Wavelet (MODWT). Six rainfall gauge station were adopted, which are located in different biomes of the region, and satellite data (CMORPH). Rainfall data were evaluated by seasonal periods (rainy and dry). The results obtained demonstrated that the MODWT-ANFIS model had the best capacity to simulate the daily precipitation of the evaluated rainfall gauge station, even for dry periods, which are known to be more difficult to be simulated in relation to the rainy periods. In this case, data entries lagged by 4 days and 5 days performed better, with Nash values close to 1.0 and root mean square errors below 0.001.
Acesso aberto (Open Access)
Estimativas de curvas IDF e curvas de permanência na Amazônia sob a influência de mudanças climáticas
(Universidade Federal do Pará, 2021-02-05) COSTA, Carlos Eduardo Aguiar de Souza; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
The impacts on global water resources may be more intense due to climate change, making access to water more difficult and, consequently, maintaining life. In the Amazon, the effect may be even worse, as it is one of the regions most vulnerable to these changes. Representative Concentration Pathways (RCPs) scenarios are essential tools for General Circulation Models (GCMs) and Global Hydrological Models (GHMs) to simulate future climate change. Intensity, Duration and Frequency (IDF) curves and flow duration curves are fundamental for the elaboration of hydraulic projects and risk management. Thus, the objective of this study was to elaborate projections of IDF curves for the Tapajós watershed in RCP 4.5 and 8.5, using data from GCMs HadGEM2-ES, CanESM2 and MIROC5. Another objective was to analyze variations in the permanence curves and available volumes of the Amazon River using data from the GHM WaterGAP2 forced by MIROC5 and HadGEM2-ES (in RCPs 6.0 and 8.5). The projected IDF curves were compared with the existing IDF, elaborated using a stationary method. The base permanence curves were created from the last 20 years of observed flows and compared with the curves of future scenarios (from 2020). They were calculated from decadal volumes. The biggest differences for the projected IDF curves were in MIROC5 (143.15% in RCP 8.5) and the smallest differences were in HadGEM2-ES (4% in RCP 4.5) both for the 100-year return period. The spatial resolutions of each GCM influenced their IDF curves, since CanESM2 did not present satisfactory results and MIROC5 was the one that best represented the possible future differences. WaterGAP2 presented the classification “Very Good” for most stations according to statistical validation indicators. Most of the extreme flows were for 2080 to 2099. For WaterGAP2 (MIROC5), most volumes were below the century's decadal average, increasing from 2060. For WaterGAP2 (HadGEM2-ES) projections the volumes are usually close or below the decadal average, falling from 2060 onwards. MIROC5 is the most suitable for studies of climate projections in the Amazon.
Acesso aberto (Open Access)
Índice de vulnerabilidade socioambiental para o enfrentamento da dengue no Estado do Pará
(Universidade Federal do Pará, 2022-04-28) LOPES, Luiza de Nazaré Almeida; TEIXEIRA, Luiza Carla Girard Mendes; http://lattes.cnpq.br/9773700229115395
Dengue is one of the neglected tropical diseases that is important for public health in Brazil, as it inspires attention due to the increased incidence of cases influenced by macro and microfactors that provide favorable conditions for the expansion of mosquito vectors and transmission of the dengue virus (DENV). The research proposes the ecological study of dengue and the construction of a Dengue Socio-environmental Vulnerability Index (IVD) to analyze 143 municipalities in the state of Pará. The IVD design considered the selection of 34 indicators of the three fundamental components of the vulnerability concept: exposure, sensitivity and adaptive capacity. The methodology consisted of the following steps: (i) selection and grouping of indicators; (ii) definition of indicators; (iii) statistical treatments; (iv) calculation of the index by multivariate analysis; (v) index normalization; and (vi) index classification using the percentile technique. In the survey, 184,000 cases of dengue were considered, of which 92,000 progressed to hospitalization by the SUS, in the period from 2001 to 2017. The epidemiological profile of dengue indicated a seasonal behavior of the disease, occurring mainly in the quarter from January to March . For the construction of the IVD, the period from 2007 to 2017 was considered, in the mapping results it was observed that 43 municipalities (30%) were classified as "Low vulnerability", with values ranging from 0.483 to 0.262. About 57 municipalities (40%) presented values with “Medium vulnerability” in the range of 0.581 to 0.483. With reference to “High vulnerability”, 43 municipalities (30%) stood out, distributed in the range from 0.771 to 0.582. The results obtained from the profile that characterized the IVD showed a predominance of “Medium to Low vulnerability”. The city of Belém, capital of Pará and located in the Guajará region, presented the lowest value for IVD (0.262). On the other hand, most municipalities in the Marajó region had the highest IVD values, namely: Cachoeira do Arari, Chaves, Ponta de Pedras, Melgaço, Santa Cruz do Arari and Anajás. The indicators that most influenced the result of the index was the “socioeconomic” factor of the populations, especially related to poverty, income, urbanization, illiteracy and solid waste management. From the application of the IVD, it can be stated that it can be used as a relevant tool for the management of dengue health surveillance in the municipalities of the Amazon region, with the potential to be studied in other regions of Brazil.
Acesso aberto (Open Access)
Influência do fator de escala, diâmetro máximo e tipo de agregado graúdo na resistência ao cisalhamento de vigas de concreto armado sem armadura de cisalhamento
(Universidade Federal do Pará, 2022-08-18) COSTA, Natasha Cristina da Silva; OLIVEIRA, Dênio Ramam Carvalho de; http://lattes.cnpq.br/1324105476558186
The present study evaluated the influence of different types and forms of coarse aggregates on the structural behavior of concrete beams with different useful heights (d) and the same base length (bw), in addition to the same longitudinal reinforcement rates (l) and dosages of concrete. For this test, it is necessary to carry out tests and tests that analyze the performance of some design codes and theoretical models in prescribing the most recent shear strength of reinforced concrete beams, without transversal reinforcement. Regarding the experimental study, 11 experimental tests of the stuttgart type were carried out until the pieces collapsed. The dimensions of the pieces were: (150 x 150 x 1400) mm, (150 x 250 x 1900) mm, (150 x 350 x 2400) mm and (150 x 450 x 2900) mm. The evaluated variables were, in addition to the geometric dimensions, the type, the dimension and the content of coarse aggregates used in the concrete dosages. When using the type of rolled pebble and a crushed stone. As for the dimensions used, pebble with maximum diameter (dmax) equal to 12.5 mm and gravel with two dmax: 9.5 mm and 12.5 mm were used. As for the content, in this work, the amount of engraved aggregate, indicated in the dosage, was reduced by 30%. In this research, transverse arms on all beams were removed, which were placed only on the supports and at the load application points to avoid damage caused by tension. In the analysis of the project codes, the requirements of ACI 318 (2019), EC2 (2004) and NBR 6118 (2014) were evaluated. It does not refer to theoretical models, discussed as proposals by MUTTONI (2019) and HUBER(2019). How to analyze besides evaluating the dispersion and conservatism of the results found, it also ranks the seconds according to COLLINS (2001) records, or the classification of demerit points -DPC. Finally, with a contribution proposal with a proposal for dimensioning reinforced concrete beams subject to shear stress, the present work presents a proposal for a correction factor, which considers the analyzed criteria, to decrease or variation coefficient calculation results based on the formulations analyzed. To suggest the proposed changes to ACI 318 (2019), EC2 (2004) and NBR 6118 (2014), two databases composed of beams tested to failure by shear were used. The first database was used to make interactions between the parameters evaluated, seeking results that would improve the normative predictions, regarding structural safety and data dispersion. And a second database was used to validate these modification proposals. The beams were numerically modeled in a computational software for non-linear finite element analysis. The calibration of the numerical models was made from the experimental results of the reinforced concrete beams tested in the experimental program of this thesis. Analyzing the models, it is observed that the numerical model was able to satisfactorily predict the experimental behavior of the beams.
Acesso aberto (Open Access)
Influência do resíduo do caulim tratado termicamente da região Amazônica e o seu potencial uso como material suplementar ao cimento Portland.
(Universidade Federal do Pará, 2022-11-23) SOUZA, Márcio Rodrigo Nunes de; PICANÇO, Marcelo de Souza; http://lattes.cnpq.br/4535052395600357
Mineral industries produce waste in large quantities and in different types and levels of danger, such as the kaolin processing industry, which produces waste based on silica, mica and kaolinite. The disposal of this material in an inappropriate place causes a strong environmental impact, which could be minimized with the use of this waste as raw material for use in civil construction. This work aims to study the incorporation of calcined kaolin residues as a supplementary material to cement and concrete for use in civil construction. In this research, kaolin residues from the Felipe mine located in the south of Amapá were used, being carried out physical, chemical and mineralogical characterization tests, the pozzolanic activity index of the calcined residues at temperatures 500ºC, 700ºC and 900ºC, as well as the analysis heat, according to ABNT standards. For the mechanical technological tests (Simple compressive strength tests, modulus of deformation and tensile strength by diametral compression) and durability (Water absorption tests by immersion and water absorption test by capillarity), were incorporated with 0%, 10%, 15% and 20% of calcined kaolin waste, replacing part of the Portland cement. The results obtained showed that the calcined residues presented high pozzolanic activity at a temperature of 700ºC, the use of calcined kaolin residue presented mechanical behavior and durability as a supplementary material to cement and concrete within the ABNT norms, and finally we concluded that there is viability technique of using waste for use in civil construction as a supplementary material to cement, as well as use for high-strength concrete.
Acesso aberto (Open Access)
Lajes lisas nervuradas bidirecionais de concreto armado sem armadura de cisalhamento com furos adjacentes ao pilar
(Universidade Federal do Pará, 2019-08-23) AGUIAR, Amaury José Oliveira de; OLIVEIRA, Dênio Ramam Carvalho de; http://lattes.cnpq.br/1324105476558186
With the need for a better understanding of the structural behavior of bidirectional ribbed flat slabs of reinforced concrete with opening adjacent to the column, aiming at the passage of installation ducts or ventilation, 15 square slabs measuring 2300 mm sides and 150 mm thickness with different opening configurations. The influence of the rectangularity of the columns was also an important topic analyzed, considering the concentration of tensions in the vertices of the loaded area. In order to do, 5 consecrated standards were used as a calculation parameter to estimate the final loads of the slabs and also to develop a new approach to estimate the loads of ruin. It is worth remembering that the analyzed slabs did not have shear reinforcement, that is, only the concrete contribution was considered to estimate the ultimate strength, although some standards associate this portion of resistance with the flexural reinforcement ratio, assigning an increase on ultimate strength. The results showed that the elongation of the opening and the column affected considerably the behavior of the slabs as well, the distribution of the stresses in the regions of the vertices of the openings. Based on data bases, it was possible to establish new parameters in the normative equations (Hi) which in turn approximated the results and decreased the dispersions of the same ones, besides a non-linear numerical analysis to have provided reliability standards in the models analyzed.
Acesso aberto (Open Access)
Método para identificação, análise e controle dos fatores de atraso de obras na gestão dos projetos de construção: um estudo baseado na metodologia multicritério construtivista de apoio à decisão (MCDA-C).
(Universidade Federal do Pará, 2023-01-26) CARVALHO, André Brasil de; MAUÉS, Luiz Maurício Furtado; http://lattes.cnpq.br/7497951647889934
The delay in works is observed globally in civil construction and affects the economy of countries, directly influencing the costs and low quality of works, the occurrence of disputes between the parties and other consequences, such as social issues related to the housing deficit, for instance. Thus, it is essential to identify the causes of work delays to minimize its consequences. In this context, the objective of this work is the elaboration of a method of identification, analysis, and control for the factors of delay of works in the management of construction projects. The research methodology included, first, a systematic review of the literature (RSL); subsequently, a survey was conducted, through questionnaires and interviews, to observe the most frequent causes of work delay, which were also evaluated for their correlations by the statistical technique of factor analysis. In this case, the results showed that the 12 main causes identified are correlated with four factors of delay of works: supply management, labor management, project management and management of weather conditions. Finally, after this first phase of the research and aiming at the development of the proposed model, the Design Science Research (DSR) method was applied in a local project management company, using as a research tool the multicriteria constructivist methodology of decision support (MCDA-C), seeking to carefully examine the decision-making process related to the delay factors observed; that were used as initial parameters in the structuring stage of the MCDA-C method. The results generated were the development and validation of the proposed method, identified as an artifact generated by the DSR, as well as the elaboration of descriptors (performance indicators) for all causes of delay evaluated. Similarly, control recommendations were obtained in the institution's performance in the factors of work delay in question, mainly regarding the management of supplies and project management that did not present satisfactory performances. In this case, it is worth mentioning the changes that occurred in the organization chart and work methodology of thecompany as actions implemented as a result of the process, carried out jointly with the decision-taker. It is concluded, therefore, that the research allowed an in-depth analysis of which issues should be prioritized in the strategies of actions aimed at minimizing the occurrence of delays in the execution of projects in civil construction and that the delay factors identified can be considered as "management deficiencies" of the enterprises.
Acesso aberto (Open Access)
Proposta analítica para estimar as resistências residuais à tração por flexão em concreto reforçado com fibra de aço
(Universidade Federal do Pará, 2022-06-15) CASTRO, Lana Daniele dos Santos Gomes; OLIVEIRA, Dênio Ramam Carvalho de; http://lattes.cnpq.br/1324105476558186
This research presents equations that estimate the residual resistances, fRi (i = 1 to 4), based on the main parameters that influence the performance of steel fiber reinforced concrete (SFRC), such as the geometric properties of steel fibers, the concrete compressive strength (fc) and fiber volume fraction (Vf). For this purpose, the research was divided into three stages, the first one consisted of creating an extensive and diversified database to, from it, develop the residual resistances equations through multiple regression. The next stage was experimental, composed of 15 beams (150x150x550) mm notched and tested to flexural tension, with variable fiber volumes, with contents of 0.0%, 0.5%, 1.0%, 1.5% and 2.0%. Finally, for the analysis of the equations elaborated in the first step, another database is presented, in which experimental results collected from the literature and those obtained in this research were inserted, and, additionally,performance comparisons were performed with four other existing analytical models. It was concluded that the analytical proposal presented by this study to define the residual resistances, in comparison with the other existing empirical models, stood out for its good performance, since it was the most accurate, less penalized and dispersed, demonstrating the reliability of the equations.
Acesso aberto (Open Access)
Punção em lajes lisas unidirecionais de concreto armado com diferentes taxas de armadura secundária e pilares retangulares.
(Universidade Federal do Pará, 2022-09-29) BRANCO, Vitor Hugo Lopes; OLIVEIRA, Dênio Ramam Carvalho de; http://lattes.cnpq.br/1324105476558186
Symmetric punching tests and experimental analyses were conducted to evaluate the behavior of nine one-way reinforced concrete flat slabs. The slabs measured (1800 x 1800 x 120) mm, and loads were applied through three types of columns: A (85 × 85) mm, B (85 × 255) mm and C (85 × 425) mm. All slabs were made with constant longitudinal reinforcement ratio at around 1% (ρx) and different secondary flexural reinforcement ratios (ρy), namely type 1 (0.5%), type 2 (1%) and type 3 (2%), approximately. Concrete compressive strength of 28 MPa and elasticity modulus of 27 GPa. Reinforcement yield stress of 573 MPa and elasticity modulus of 244 GPa. Column rectangularity index (cmax/cmín) and secondary reinforcement ratio were the main research variables, and the present study evaluated their influence on the ultimate punching strength of the sampled one way reinforced concrete flat slabs. The experimental results were compared with four current international standards: ACI 318 (2019), EC2 (2004), MC 2010 (2011) and NBR 6118 (2014). They were also compared with the findings from a nonlinear numerical analysis made with the software ABAQUS CAE 6.14, based on the Finite Element Method (FEM) and on the Concrete Damage Plasticity (CDP) model. The results indicated that the standards need to be updated, and that there is a proportional increase of up to 50% approximately in slab punching strength when the secondary reinforcement ratio is increased by up to 2%.

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