Programa de Pós-Graduação em Engenharia Civil
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Master Thesis A promoção imobiliária e as vias arteriais: um estudo sobre correlação espacial em Natal/RN(Universidade Federal do Rio Grande do Norte, 2021-08-18) Silva, Thayanne Lara Gondim; Queiroz, Luiz Alessandro Pinheiro da Câmara de; http://lattes.cnpq.br/4961054145787883; http://lattes.cnpq.br/5849433589688288; Sousa Júnior, Almir Mariano de; Lucena, Luciana de Figueiredo Lopes; http://lattes.cnpq.br/5893551656862490; Melo, Magda Maria Pinheiro deThe real estate development developed in the city of Natal followed the economic transformations and urban legislation in force in the city, defining the location of the projects and their typological characteristics, acting as an important agent for transforming the urban space. The performance of real estate developers contributed to the process of urban expansion, promoting population density in specific regions of the city. The consequent increase in the number of vehicles and the deficiency in the expansion of road infrastructure resulted in the compromise of urban mobility. This work aims to establish possible spatial correlations between vertical housing production, in the period from 1990 to 2018, and arterial roads in the city of Natal. For this, an extensive database was used, and, through the QGIS® software, aspects of the spatial distribution of the projects were defined, emphasizing the number of housing units, the verticalization (number of floors) and the number of parking spaces . The results point to an asymmetrical distribution of housing units between the administrative zones of Natal, but a direct relationship between the construction of projects and arterial roads, since many of them follow the extension of these roads. The East and South Zones concentrate the largest number of housing units, buildings with the highest number of floors and with greater availability of parking spaces, unlike the North and West Zones, which bring together real estate production for populations with lower purchasing power. The existence of infrastructure, the concentration of stores, services in education, health and leisure and better access routes may justify the greater intensity of projects in the East and South Zones, revealing possible criteria in the decision-making process of real estate developers. Due to the proximity of the properties to arterial roads, congestion points, environmental pollution by the emission of gases and higher noise levels can already be observed in these areas. The conclusions of this research can support both the decisionmaking of promoters and contribute to the public authorities to adopt measures and actions to guide the best use of infrastructure, without compromising urban mobility, affecting the quality of life of people.Master Thesis Estudo numérico de armaduras complementares em blocos sobre duas estacas com cálice parcialmente embutido com chave de cisalhamento(Universidade Federal do Rio Grande do Norte, 2022-11-25) Morais Neto, João Aurimar Correia de; Barros, Rodrigo; http://lattes.cnpq.br/6314974214441091; http://lattes.cnpq.br/0085233220549740; Munhoz, Fabiana Stripari; Araújo, Daniel de Lima; Nascimento Neto, Joel Araújo do; http://lattes.cnpq.br/2747505817148030Pile caps are foundation elements that presents a complex structural behavior and are characterized by the presence of several sets of reinforcement that aim to improve their characteristics when loaded. In this context, this paper aimed to study the influence of the inclusion of complementary vertical reinforcement in two pile caps with partially embedded socket with shear key interface and to propose new configurations of auxiliary reinforcements for its detailing. Non-linear three-dimensional numerical analyzes were developed using the ABAQUS finite element software. The numerical study was preceded by a peak force calibration step based on experimental results obtained by Barros (2013). After calibrating the model, numerical studies were carried out containing the complementary vertical reinforcement, first, presenting the experimental parameters shown by Barros (2013) and then another study where the fcm of the cap was varied between 35, 40, 45 and 50 MPa, which also considered different reinforcement arrangements and steel areas. Stress levels in concrete and reinforcement, shape of struts, slope of stress vectors, cracking and failure mode were analyzed. The results showed that the inclusion of the complementary vertical reinforcement did not cause significant changes in the models studied, even when magnified by four times their steel area. However, the studies identified high tensile stresses in the concrete mass located in the region between the column and the pile with inclinations angle close to 30º, which are caused by the shear of the cap. Based on the reinforcement of such tensile stresses, this research analyzed four proposals for complementary reinforcement. With the exception of the “MA” proposal, the other reinforcements showed satisfactory results in terms of increasing the inclination and shape of the connecting rod, reducing internal cracks in the concrete mass, reducing tensile stresses in the cap and transfer the central loads to regions over the piles. Such benefits translated into an increase in the load capacity of the block by 4,64% to 12.79%.Master Thesis Efeito do teor de finos nos parâmetros de estados críticos de solos transicionais(Universidade Federal do Rio Grande do Norte, 2022-09-01) Santos, Valteson da Silva; Santos Júnior, Olavo Francisco dos; https://orcid.org/0000-0001-7552-6646; http://lattes.cnpq.br/1573496204231636; http://lattes.cnpq.br/0930157046063345; Araújo, Arthur Gomes Dantas de; Freitas Neto, Osvaldo de; https://orcid.org/0000-0001-9488-4123; http://lattes.cnpq.br/6335708403185496Mixtures of sand and fines exhibit different behaviour than pure materials. These mixtures are referred to as transitional soils. Several studies have found that there is a fines content above which the properties of the mixture are dominated by the fines matrix. This parameter is referred to as the transitional fines content. Freire (2019) determined compressibility and strength parameters for mixtures of fines and sand from the Post Barreiras Formation collected in the city of Natal, Brazil. This work, which continues the work of Freire (2019), aimed to analyse the critical state parameters of the same materials. The finenesses used were: 0, 10, 20, 30, 40, 50, 75 and 100 mass percent of the sandy fraction. Geotechnical characterization tests were performed to determine the critical state parameters. Triaxial tests were performed. For the undrained triaxial tests were performed. Effective compressive stresses of 50 kPa, 100 kPa, and 200 kPa were used for the undrained triaxial tests. It was found that the critical state line was not unique for the tested compounds. The threshold value for the fineness determined using the Ueda model varied from 19.7% to 24.3%. The maximum effective friction angle was observed for the transition fines content. The Alfred packing model proved to be a good tool for determining the fines content that gives the highest effective friction angle for the critical condition. The results show that the size distribution of sand and fines significantly affects the transition fines content. This work also proposes the application of a topological hypothesis (TH) to the phase transitions of soil mixtures. Considerable changes in the topology of the mixtures are found, confirming the transitional behaviour. Finally, the concept of critical states is discussed from a topological point of view as the state of maximum entropy.Master Thesis Degradação térmica e mecânica de geossintéticos utilizados em restauração de pavimentos flexíveis com concreto asfáltico(Universidade Federal do Rio Grande do Norte, 2022-08-29) Mello, Micheline dos Anjos e; França, Fagner Alexandre Nunes de; https://orcid.org/0000-0002-8113-622X; http://lattes.cnpq.br/6854485206744906; http://lattes.cnpq.br/6794313787778784; Amorim, Enio Fernandes; Portelinha, Fernando Henrique MartinsThe road transport is responsible for a large part of the transport of cargo and people in Brazil, therefore, keeping pavements in good condition implies benefits for the economy and for users, however, it is common for flexible pavement to crack throughout its lifetime. Usually, a new bituminous layer is adopted to repair cracked pavements, but in a short time the cracks are reflected or propagated from the old layer to the new one. A solution adopted to reduce and delay the reflection cracking is the use of geosynthetics, however, these materials can be thermally and mechanically damaged during the installation process. In this way, it is important to verify if these damages are considerable and if they hinder the materials from fulfilling the function for which they were designed. Thus, this research aims to analyze the thermal and mechanical degradation suffered by geosynthetics used as anti-reflective cracking systems and, additionally, to verify if there is an improvement in this analysis with the use of aluminum foil. For this, four types of geocomposites were used and their samples were classified into: virgin samples, which were not subjected to damage; thermal damage samples, on which the asphalt concrete with high working temperature was deposited and uniformed; thermal and mechanical damage samples, which, in addition to being subjected to the effect of high temperature, were also exposed to mechanical action due to asphalt concrete compaction. All the damaged samples were divided symmetrically and in one part aluminum foil was placed before exposure to the damage and in the other part the asphalt mixture was placed directly, therefore, the damaged samples were categorized as with and without aluminum foil. Afterwards, the samples were cut and subjected to uniaxial tensile tests. The results of the tensile tests provided parameters such as tensile strength, grip displacement and slope of the lines. Such parameters were analyzed and used as degradation indicators. Regarding tensile strength, the biggest reduction was for glass fiber geocomposite that was subjected to thermal and mechanical damage, while, the smallest, 2,45%, was for the polyester geocomposite exposed only to the high temperature of the asphalt concrete. From the results, it was possible to conclude that the materials suffer degradation in the installation process and that its severity depends on the geosynthetic raw material, as well as the damage to which it was subjected.Master Thesis Metodologia para o mapeamento de movimentos gravitacionais de massa: estudo de caso na praia de Pipa, município de Tibau do Sul/RN(Universidade Federal do Rio Grande do Norte, 2022-08-29) Silva, Luana Raquel Juvino da; Amaro, Venerando Eustáquio; Scudelari, Ada Cristina; http://lattes.cnpq.br/4215328958233942; http://lattes.cnpq.br/8740397244007924; Ingunza, Maria Del Pilar Durante; https://orcid.org/0000-0001-6994-7559; http://lattes.cnpq.br/1925954531585024; Araújo, Paulo Victor do NascimentoThe eastern coast of the Rio Grande do Norte (RN) is the domain of active cliffs and sandy beaches, often associated with mobile dunes and fixed by vegetation, intercepted by rivers and estuaries. Along this gological and geomorphological context of natural fragility of the seashore is inserted the Municipality of Tibau do Sul, specifically the stretch of Pipa Beach, where socioeconomic activities are strongly based on international tourism, with repercussions on national and regional tourism, encouraged by the opportunities of business and investments in the real estate sector, in addition to the construction of second homes. Such factors indicate the importance of tourism and real estate activity for the municipality and, consequently, with relevant public and private financing and investments on a range of seafront subjected to intense natural and anthropogenic coastal dynamics, in which disasters have occurred due to use and occupation of land carried out inadequately and based on ineffective public policies. Therefore, the present work presents a methodological proposal based on geotechnologies and the integration of spatial data in Geographic Information System, reports of historical rainfall data and data from reanalyzes of the wave climate, for the determination of risk indices to coastal erosion and gravitational mass movements, in the section of Pipa Beach/RN. Vulnerability indices were calculated through weighted statistical analysis of thematic classes of geology, geomorphology, land use and occupation, slope, vegetation and extreme precipitation events. The validation of the thematic maps took place throughout the field surveys, in which coastal erosion processes were also verified and investigated, the points of flooding and surface rainwater runoff, as well as the existence of containments structures improperly implanted, which end up enhancing the process of coastal erosion in the area. From the compilation of information collected in the field and analysis of the previous maps, a methodological proposal was elaborated to coastal erosion and gravitational mass movement risk map was elaborated to areas defined as high risk (R3) and very high risk (R4). The indexes were calculated through weighted statistical analysis of thematic classes of geology, geomorphology, land use and cover, slope, vegetation and extreme precipitation events. The coastal erosion and gravitational mass movement risk map is essential to strengthen the understanding of coastal areas and provide, to the public managers responsible for the coastal environmental and the community at large, with information that assists in decisions regarding the interventions that could be taken to reduce the degree of risk and in the preparation of contingency plans, as well as for licensing and inspection decisions on coastal regions.Master Thesis Análise de confiabilidade da fundação de um viaduto hiperestático: estudo de caso(Universidade Federal do Rio Grande do Norte, 2022-08-22) Cortez, Fábio Lindemberg Coelho; Costa, Yuri Daniel Jatobá; Costa, Carina Maia Lins; http://lattes.cnpq.br/6483888857335060; http://lattes.cnpq.br/6737841388506901; http://lattes.cnpq.br/9717519832735012; Bezerra, John Eloi; Oliveira, Leonardo Henrique Borges deReliability analysis is an important tool for quantifying uncertainties involved in the design and construction of civil engineering structures. Appropriate failure probabilities and safety factors associated with the maximum allowed risk can be assessed from a reliability analysis. The purpose of this research is to estimate the failure probability of the pile foundation of a hyperstatic viaduct. The foundation of the viaduct included 43 steel H-piles, driven with a hydraulic hammer. The reliability analysis was carried out using the method put forward by Cintra and Aoki (2010) and the Monte Carlo simulation. Mobilized vertical resistances on the piles were estimated using the dynamic formulations by Chellis (1951) and Smith (1960) modified by Aoki (1996). The input parameters required in these formulations are the pile embedded length, the set and the elastic rebound, and were obtained in the field during the driving of the piles. Vertical loads on the top of the piles were estimated following Brazilian standards NBR 7187/2003 and NBR 7188/2013, as well as the Engesser-Courbon method. The input parameters were fitted to normal distributions and were tested with the KolmogorovSmirnov hypothesis test. Cintra and Aoki’s (2010) method provided convergent results for both dynamic formulations, around 1/2000. On the other hand, the Monte Carlo method yielded divergent failure probabilities, equal to 1/196 and 1/10000, for the solutions by Chellis (1951) and Smith (1960) modified by Aoki (1996), respectively.Master Thesis Identificação e avaliação de pontos de alagamentos nos bairros Petrópolis e Ribeira na cidade de Natal/RN com suporte de geotecnologias(Universidade Federal do Rio Grande do Norte, 2022-08-26) Eduardo, Antunes França; Amaro, Venerando Eustaquio; http://lattes.cnpq.br/4215328958233942; http://lattes.cnpq.br/9020740739377703; Scudelari, Ada Cristina; Santos, Marcelo Soares TelesUrban flooding are frequent in Brazilian cities due to soil sealing caused by the disorderly urbanization of cities, the occurrence of extreme precipitation events and failures in the urban drainage system. In the city of Natal/RN, the traditional neighborhoods of Ribeira and Petrópolis have flood points that cause socioeconomic and health disorders to the population. Thus, this study aims to identify and evaluate areas susceptible to flooding in these neighborhoods based on the use of geotechnologies. For this purpose, data on land use and cover, urban drainage system and topographic data provided by public agencies were integrated into the Geographic Information System (GIS) environment. In this way, ground control bases obtained in loco with the Global Navigation Satellite System (GNSS) were used to guarantee data with better precision to generate the Digital Terrain Model (MDT) and the Digital Surface Model (MDS) that allow the identification of topographical depressions and determination of the direction of surface flow of rainwater. The results showed the occurrence of eight depressions, among which six with historical occurrence of flooding and surface flow confluence, in addition to revealing that the rainwater drainage system is poorly distributed and/or in precarious conditions in six topographical depressions. Therefore, these areas around the topographical depressions are areas of high susceptibility to flooding in the study area.Master Thesis Degradação de geossintéticos por intemperismo natural em área costeira(Universidade Federal do Rio Grande do Norte, 2022-08-30) Silva, Rayanne Karlla Santos da; França, Fagner Alexandre Nunes de; Costa, Yuri Daniel Jatobá; http://lattes.cnpq.br/6737841388506901; https://orcid.org/0000-0002-8113-622X; http://lattes.cnpq.br/6854485206744906; https://orcid.org/0000-0003-2065-5154; http://lattes.cnpq.br/2008251932880307; Amorim, Enio Fernandes; Portelinha, Fernando Henrique Martins; Medeiros, José Ivan deGeosynthetics are polymeric materials used in several engineering projects. Among them, it is use in coastal protection constructions stands out with high application potential, together with granular materials to control erosion. Durability, after exposure to the weather, needs to be known for more precise sizing. How any polymeric material, they are subject to degradation due to exposure to UV radiation. Both ASTM D5970 (2016) and ASTM D1435 (2013) standards contain guidelines for geosynthetic exposure to UV radiation. In this sense, this work presents a comparison between the two patterns by the change in the exposure slope of a PP geotextile in a coastal environment at the seaside of Natal/RN. In addition, the influence of color and consequent temperature of the exposure table, as well as it is interaction with granular material, was evaluated. The exposure time was 176 days, divided into three distinct periods (42, 84 and 176 days) and the tensile strength of the samples was compared with those obtained from virgins. The results indicated small differences in UV degradation due to exposure inclination. On the other hand, the color of the exposure table produced greater degradation in those samples exposed on black tables, when compared to those on white tables and the most critical result was for the samples exposed in sand. The data obtained in this study are fundamental for the dimensioning and adoption of mitigating measures in coastal engineering works that use geosynthetics.Master Thesis Modelo constitutivo NorSand aplicado à areia de duna de Natal(Universidade Federal do Rio Grande do Norte, 2022-08-31) Araújo, Plenyo Nahen Gonzaga; Santos Júnior, Olavo Francisco dos; Freitas Neto, Osvaldo de; https://orcid.org/0000-0001-9488-4123; http://lattes.cnpq.br/6335708403185496; https://orcid.org/0000-0001-7552-6646; http://lattes.cnpq.br/1573496204231636; http://lattes.cnpq.br/4544020901975402; França, Fagner Alexandre Nunes de; https://orcid.org/0000-0002-8113-622X; http://lattes.cnpq.br/6854485206744906; Severo, Ricardo Nascimento FloresThe study of soil behavior is essential for successful disaster prevention and mitigation, as mass movements may occur in catastrophic proportions, leading to many failures, deaths, and significant financial losses. A flow slide occurred in Natal, Brazil, and raised the demand for evaluating the Natal dune sand's behavior regarding the susceptibility to static liquefaction. For this purpose, a numerical investigation was performed through a constitutive modeling approach. The present work aims to evaluate the performance of the NorSand model by assessing the Natal dune sand behavior under different conditions of drainage and state. NorSand is a model based on Critical State Soil Mechanics, using the state parameter as a reference for the model properties. The model parameters were obtained by 16 triaxial compression tests, varying pressure, state, and drainage conditions. The validation of the model was accomplished by comparison between laboratory tests and numerical simulations. A parametric analysis of undrained tests was carried out in order to fit the numerical curves to this drainage condition. The void ratio of loose sands was also varied. In addition, triaxial tests were simulated on samples subjected to intermediate stresses. Moreover, numerical simulations with confining pressure p´ = 100 kPa in contractive samples were confronted with the MohrCoulomb response. The model calibration showed a satisfactory response in comparison to the real lab tests. The parametric analysis evaluated the influence of some model properties in undrained conditions. The stress-dilatancy and hardening properties indicated a large influence on curves. The void ratio variation on loose samples showed the development of static liquefaction until the soil presented total strength loss. Simulations with intermediate stresses showed the expected behavior to these stress conditions, and confirmed the validation of the model. In addition, the comparison between NorSand and Mohr-Coulomb models presented the sophistication of an elastoplastic model regarding simpler theories when submitted to the same conditions. In drained conditions, the stress-strain curve indicates a similar ending behavior between both models, but the similarities are restrained to this curve. In undrained conditions, the Morh-Coulomb model shows unrealistic outcomes regarding static liquefaction.Master Thesis Caracterização geotécnica de solo estabilizado com cimento e cinzas de resíduos sólidos da saúde(Universidade Federal do Rio Grande do Norte, 2022-08-12) Alencar, Victor Lindemberg de Lima; Ingunza, Maria Del Pilar Durante; http://lattes.cnpq.br/5101325970707258; Bandeira, Ana Patricia Nunes; Amorim, Enio Fernandes; https://orcid.org/0000-0001-7386-3956; http://lattes.cnpq.br/3436413268425331This work presents the analysis of the physicochemical, mineralogical and mechanical behavior of a soil stabilized with Portland cement and ash from Solid Health Waste (SHW). From this, the technical feasibility of using this compound in layers of road pavements was investigated. A sandy soil, ordinary Portland cement with addition of blast furnace slag (CP II -E) and SWH ash were used. The methodology involved the execution of soil geotechnical characterization tests and the mechanical behavior of soil-cement and soil-cement-ash mixtures. Compaction tests were carried out on specimens molded with pure soil and soil-cement in normal, intermediate and modified energies with cement contents added of 0%, 3%, 6% and 9%, in order to determine the cement content ideal. The soil-cement mix that presented the best result was with the addition of 9% of cement in relation to the soil mass, using the modified energy, there was an increase in resistance of 8.95% in relation to the initial one. The CBR test was carried out in pure soil, at normal energy and with humidity above 5.94%, the minimum values of CBR required for sub-base were reached, however, the values required for use in bases were not reached. of floors. Simple compression tests were carried out and, with normal compaction energy and 9% cement content, the result of 25.31 kgf/cm² was found, which meets the minimum required for the use of soil-cement in pavements. This cement content was used for the compression tests with the soil-cement-gray, using 5%, 10% and 20% of ash to replace the soil and with normal energy, the values of 56.62 were obtained. kgf/cm², 38.43 kgf/cm² and 32.46 kgf/cm², respectively. In all traces with the addition of RSS ash, the values of the simple compressive strength obtained an increase. The incorporation of up to 20% of ash to the trace demonstrated that it is technically feasible to use RSS ash in the chemical stabilization of soilcement in sub-bases and pavement bases. Therefore, a solution is presented for adequate disposal of SWH ash, allowing the reduction of soil use in the trace and increase in resistant properties.