Teses em Engenharia Civil (Doutorado) - PPGEC/ITEC

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

Navegar

Agora exibindo 1 - 20 de 20

Acesso aberto (Open Access)
Modelo para estimar o prazo de execução de obras residenciais verticais: por meio da lógica fuzzy
(Universidade Federal do Pará, 2017-05-26) MAUÉS, Luiz Maurício Furtado; DUARTE, André Augusto Azevedo Montenegro; http://lattes.cnpq.br/1135221873341973
The definition of the execution time of vertical residential buildings occurs, in most cases, empirically and during the economic and financial feasibility study of the project. This generates high risks and uncertainties regarding the deadline compliance. However, there are tools of computational intelligence that can contribute to the reduction of the degree of uncertainty, among them the fuzzy logic. This work aims to develop a hybrid model to estimate, in a reasonable way, the construction period of vertical residential buildings by associating factor analysis and fuzzy logic. For this it was used a database from the Municipal Secretary of Urban Development of Belém (SEURB) and the developers of the city, which are target of the case study, in the period from 08/24/2015 to 09/11/2015. To build the model, in the first step, i.e., the factor analysis, 127 projects were used; in the second step, the fuzzy inference, 71 projects were used; and, for the validation phase, 16 projects were used. Results obtained showed a significant level of assertiveness, with accuracy of 75%, taking into account an interval whose limits (upper and lower) were calculated in the mean absolute percentage error (MAPE). The model delivered a prediction performance superior to other models already accepted in literature. As theoretical contribution, the work allows a better understanding of the uncertainties and risks regarding the definition of the execution time of real estate projects, and also about how the modeling can help entrepreneurs/construction campany and technicians to make better decisions based on a hybrid model, considering the uncertain and complex environment of the economic and financial feasibility study phase for future projects.
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)
Bem-estar no trabalho: proposta de uma escala para operários da construção
(Universidade Federal do Pará, 2019-10-08) MOREIRA, Felipe de Sá; DUARTE, André Augusto Azevedo Montenegro; http://lattes.cnpq.br/1135221873341973
Well-being concepts, which are widespread in the social sciences, are gaining more space and are being worked on in several other areas. Two theories of approach are typically used: subjective well-being through hedonic theory and psychological well-being supported by eudaimonic theory. Based on these theories the field of study called well-being at work (WBW) was developed, which seeks to understand the factors that provide happiness or well-being in organizations. Despite the intensive use of labor, the construction industry does not seem to apply such knowledge, but develops many aspects of worker quality of life. Thus, the objective of this research is to propose a scale of WBW aimed at the workers in the construction industry. For this, the Item Response Theory (IRT) was used to design the instrument used in the scale. Through a Systematic Literature Review (RSL) conducted in 10 research bases, 92 studies were mapped that pointed out 89 aspects related to the welfare of this group of workers. Based on these aspects, several instruments already validated in other researches were sought to constitute the initial instrument of this study, which consists of 53 items related to the following themes: WBW, stress, work-family relationship, safety, alcohol and tobacco consumption, physical health and musculoskeletal disorders. The instrument was applied to 376 construction workers. The results were tabulated and IRT was applied using the Samejima model for gradual items. The final instrument is composed of 32 items, since 2 items had reduced factor loading (less than 0.30) and 19 items had low discriminatory power (below 0.65). The scale consists of 5 levels (-2, -1, 0, +1 and +2), classifying the individual according to their perception of the following aspects: WBW, stress, work-family relationship and physical health. This research is expected to contribute to the theoretical framework of WBW, as well as to the promotion of such perspectives in civil construction.
Acesso aberto (Open Access)
Modelo para obtenção de incentivos fiscais de ICMS aplicados à cadeia produtiva da construção: uma análise da indústria de cerâmica vermelha
(Universidade Federal do Pará, 2021-01-29) FARIAS JUNIOR, Claudionor Andrade; DUARTE, André Augusto Azevedo Montenegro; ttp://lattes.cnpq.br/1135221873341973; https://orcid.org/0000-0003-4586-1587; NEVES, Renato Martins das; http://lattes.cnpq.br/6538317425557058
This thesis aims to analyze and propose guidelines to the criteria inherent to the ICMS legislation applied to Industries in General, establishing a model directed to the Construction Production Chain with emphasis on the Pará Red Ceramics Industry. To this end, it adopted theoretical concepts related to the characterization of its research universe as well as the main aspects pertinent to fiscal taxation in the referred chain, distancing itself from the legal and accounting approaches. As a central reference of the study, the model recommended by the state law of Pará, which provides for special tax treatment applicable to “industries in general”, is notable. To carry out the investigation, the quantitative research method was adopted, with the application of an electronic questionnaire to the group of industries belonging to the main ceramic pole in the northern region of Brazil. From the realization of the field research, the quantitative data collected were analyzed through the use of statistical techniques of descriptive and inferential analysis (multiple linear regression, cluster analysis, and analysis of variance). The results obtained give rise to divergent positions related to the theoretical and empirical validation of the original model. As for the empirical compartment, it is suggested: (1) the revision of the way of measuring the data referring to the variables “Innovation” and “Sustainability, with emphasis on gaining variability in the related data; and (2) the review of the scores (weights) attributed to these two variables, with emphasis on their corresponding levels of benefits achieved. As a relevant result, it is also worth highlighting the mapping of the investigated sector, highlighting: (1) the assessment of the framework of the companies participating in the research, concerning the reach of the different levels of benefit; and (2) the grouping of units (firms), considering the measure of similarity of the responses obtained. Conclusively, as a theoretical and managerial contribution, we highlight the filling of an important gap in the field of study related to the tax benefits applied to the construction production chain, such as the emphasis on the importance of a scientific foundation for the formulation of legislation associated with global public policies. Particularly, the contribution directed to the legislators of the different states of the federation, supporting the reflection and discussion about the impact of the variables "Innovation" and "Sustainability" in increasing the condition of competitiveness for companies.
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)
Modelo para resistência de cisalhamento em vigas de concreto sem estribos
(Universidade Federal do Pará, 2021-11-30) LIMA, João Carlos Lisboa de; OLIVEIRA, Dênio Ramam Carvalho de; http://lattes.cnpq.br/1324105476558186
The analysis of shear strength in concrete beams involves significant complexities and iteration between parameters. The development of models for the design and verification of the ultimate limit state of beams began in the 19th century with empirical, theoretical and numerical models such as the Ritter-Mörsch truss analogy and the modified compression field theory. However, the almost stochastic ratios of compressive strength of concrete, longitudinal reinforcement ratio, loading slenderness, transverse dimensions and coarse aggregate diameter add up to numerous difficulties in creating simple and easily applicable formulas. Thus, the present work aims to develop a model based on proportionality relations and the application of an iterative algorithm to optimize the values of an initial database of 220 beams (62 authors) that failure by shear and define a theoretical model that will be compared with a database of 510 beams (63 authors) and other methods of calculation of relevance. The proposed formula provided a coefficient of variation of 6.23%, being between 34.97% and 59.52% lower than the models analyzed. Thus, the results of the proposed method, when considering the experimental and theoretical relationship of the database, present all values within the appropriate safety range, allowing greater accuracy in defining the ultimate load of concrete beams without stirrups.
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)
Método para capacitação de ocupantes de edifícios residenciais em segurança contra incêndio
(Universidade Federal do Pará, 2022-03-24) SARAIVA, Raísse Layane de Paula; MAUÉS, Luiz Maurício Furtado; http://lattes.cnpq.br/7497951647889934; Https://orcid.org/0000-0002-1762-8617
Despite the existence of norms, laws and executive orders that provide safety in residential buildings, fires continue to occur in Brazil and worldwide and can be fatal given their severity and provided occupants do not know what to do. This problem becomes even more complex in high buildings (height greater than 30 meters), where fire protection systems are employed, but still there is no – in Brazil – mandatory fire training for occupants. Authors focused on the study of human behavior in fire situations have already stated that the adequacy of responses (or behavior) is the key for the building to be safely abandoned in case of need and to ensure greater safety to the building occupants. In view of the above, this work, through Design Science Research (DSR), aimed to develop a fire training method for occupants of tall residential buildings. The method had two aspects of composition: i) theoretical analysis (where norms, laws, executive orders, good practices and fires already occurred were used as sources of information) and ii) computational simulation (where the hypotheses were tested). As products, a flowchart and a listing of the contents to be used in the training were developed. Then, the method was validated, analyzing the internal validity, external validity, content validity and construct validity. To this end, specialist professionals from the Fire Department, in 12 Brazilian states, answered 42 questionnaires attesting to the validity of the method and considering it appropriate, understandable, objective, replicable and appropriate for the objective to which it was available. In addition to confirming the negative impact of premovement time, it was also possible to verify that the number of occupants in the building, as well as the distances covered by these are extremely important factors in the abandonment process and should be verified in new projects aimed at improving their safety. In addition, three buildings were used for the development of the study and had the training method applied, finally being evaluated by the occupants themselves and training participants, who considered it acceptable and responsible for providing them with more safety.
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)
Desenvolvimento de sistema computacional integrado de dimensionamento e representação gráfica de canais de macrodrenagem
(Universidade Federal do Pará, 2022-05-23) MARTINS, Vania Carla Dias; PEREIRA, José Almir Rodrigues; http://lattes.cnpq.br/9918600634569244; https://orcid.org/0000-0002-3144-1787
Develops an integrated computer system for the design and graphic representation of macrodrainage channels, including the hydrological, hydraulic, hydrodynamic design steps and graphic design elements. The system conceived and named SIDCAM was developed with a central model built in Java (MACRO 1.0), which is integrated with three external software, Google Earth, HEC-RAS and AutoCAD. For this, the research was carried out in three stages: (1) identification of methods and software, necessary for the development of a macrodrainage project; (2) development of the software in Java, for the hydrological and hydraulic design stages (phase 1), and, development of tools for integration, import and export of data, between the hydraulic module and the HEC-RAS and AutoCAD software (3 ) evaluation of the functionality and reliability of SIDCAM, through its application in the case study of the macrodrainage project of Tucunduba, Belém/PA. SIDCAM is composed of four modules: the hydrological module, for the generation of hyetograms and project hydrographs, using the alternating blocks and triangular hydrograph (SCS) methods; the hydraulic module, for making the geometric design of the channel and the coincidence of flow peaks with high tide peaks; the hydrodynamic module, to validate the SIDCAM geometric design; and the graphic module, for the automatic production of editable graphic pieces, of longitudinal and transverse profiles. In addition to the modules, import directories of IDF and tide gauge curves were built, fed by two databases, for IDF coefficients of 165 Brazilian municipalities and tide gauge curves of 334 stations of the Brazilian Navy. In the analysis of the water levels in the channel, simulated by the developed system, most of the results were classified as “Good” and “Very Good”, with Nash-Sutcliffe coefficients greater than 0.97, a minimum percentage error of 1.19% and a maximum of 14.72%. In view of these results, the proposed tool is promising, especially because it is a model that concentrates a good part of the processes necessary for a macrodrainage project, in a single integrated structure, thus filling gaps left by current models, which have a dissociative approach to the different stages of the project.
Acesso aberto (Open Access)
Avaliação da sustentabilidade da gestão dos resíduos sólidos urbanos de municípios paraenses
(Universidade Federal do Pará, 2022-05-24) NEVES, Raisa Rodrigues; FERNANDES, Lindemberg Lima; http://lattes.cnpq.br/4641468846318922
The research aimed to evaluate the quality of urban solid waste management, considering the actions taken and the information provided in the Municipal Plans for Integrated Management of Solid Waste (PMGIRS). For this, an initial matrix composed of 73 indicators was structured, which went through filtering stages, in order to extract information with low potential to be answered by municipal managers, giving rise to the final matrix of 40 indicators incorporated into 7 dimensions, basing the elaboration of the questionnaires used in this work. Initially, there was the application of questionnaires to managers to obtain knowledge about the reality of local management; then, the questionnaires were sent to the experts selected to participate in the Delphi Method. In total, 5 groups answered the questions on the 7 dimensions, which provided scores from 1 to 5 for each indicator and weights for each dimension. Based on the managers' responses, on the final grades of each indicator and on the final weights of each dimension, it was possible to calculate the Solid Waste Management Quality Index (IQGRS), framing the values found in sustainability levels. Then, the same methodology was applied to evaluate the quality of preparation of the PMGIRS, being proposed the Quality Index of the PMGIRS (IQPMGIRS), in this way it was possible to compare what was being done in practice and what was provided in the text of the instrument. of planning. As a result in terms of management, 4 municipalities presented unsustainable conditions, 4 presented regular sustainability, 5 presented good sustainability and only 3 presented excellent sustainability. After the application of clustering techniques in terms of management, 5 groups were formed, with Inhangapi and Canaã dos Carajás included in the group with the best performance; Abel Figueiredo, Augusto Correa and Curuçá were included in the group with the worst performance. Clustering was also applied regarding the quality of PMGIRS, guaranteeing the formation of 5 groups, with the group with the best performance being formed by Abaetetuba, Bonito, Goianésia do Pará and Juruti; the group with the worst performance was composed of Acará and Concórdia do Pará. The groups with the worst performances reflected the need for investments and progressions both in terms of management practice and in terms of improvements in PMGIRS, in order to guarantee the effectiveness of PMGIRS as a decision-making tool.
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)
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)
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%.
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)
Emprego de Resíduo de Silício Metálico como Material Pozolânico na Produção de Cimento Portland Composto
(Universidade Federal do Pará, 2022-12-19) CUNHA, Rodrigo Rodrigues da; MACEDO, Alcebíades Negrão; http://lattes.cnpq.br/8313864897400179
Civil construction, despite being an extremely important sector for the country's economic development, consumes a very significant amount of natural raw materials, in addition to being responsible for most of the consumption of cement produced in the world. The production of this material, in turn, causes many environmental impacts, resulting mainly from the sintering stage of clinker (main constituent of cement), which causes the emission of thousands of tons of CO2 into the atmosphere. In this sense, several studies have been carried out in order to point out an alternative material that can be used as a mineral addition to cement instead of clinker. Much of this research has sought to study the use of additions manufactured from the use of industrial waste. Given this context, the present work aims to analyze the behavior of a modified Portland cement of the CPIIZ-32 type, produced with partial replacement of clinker, by a residue from the pre-separator of the ferrosilicon - metallic silicon manufacturing process. - from an industry located in Breu Branco/PA. Therefore, at first, the physical and chemical characterization of the residue in natura and processed form was carried out, through the milling process, from the specific mass, FR-X, DR-X and activity index tests. pozzolanic with lime and cement. Then, 5 (five) blends of composite cement were formulated with different contents of ground silicon metal residue to analyze the mechanical behavior at 28 and 90 days of curing. Finally, a comparison was made of the physical-mechanical performance of the mortars produced with the use of modified cement and commercial cement of the CPIIZ-32 type. The results showed that the metallic silicon residue, after going through a pre-benefiting process (grinding for a period of 60 minutes) obtains properties consistent with the requirements stipulated by NBR 12653 (ABNT, 2014) to be considered as a pozzolanic addition. The use of this by-product for this purpose can generate enormous environmental benefits, reducing the impacts resulting from the clinker production stages, as well as being a viable alternative for the reverse logistics of this material, since the generating companies still do not have any form of reuse for this residue.
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)
Concreto permeável geopolimérico aplicado na pavimentação
(Universidade Federal do Pará, 2023-03-07) ARAÚJO, Wendel Melo Prudêncio de; MACEDO, Alcebíades Negrão; http://lattes.cnpq.br/8313864897400179
In the recent scenario, groundwater retention plays a key role in achieving environmental sustainability. This can be achieved by using pervious concrete as a paving material in roads, parking lots, garden areas and low traffic road applications. Due to its mechanical limitation, much research has been carried out to develop a more resistant material. Geopolymeric permeable concrete is synthesized by the alkaline activation of materials rich in aluminate and silica in an alkaline medium. This work aims to produce samples of geopolymer permeable concrete, using red ceramic residue and metakaolin as precursors, for application in permeable paving. The results showed that the use of red ceramic in the production of pervious geopolymer concrete up to a concentration of 30% is feasible, since higher concentrations can compromise the physical, hydraulic and mechanical properties.
Acesso aberto (Open Access)
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)
Identificação e quantificação de desplacamento cerâmico em fachadas de edifícios no contexto da indústria 4.0
(Universidade Federal do Pará, 2023-03-24) SOUSA, Alcineide Dutra Pessoa de; MAUÉS, Luiz Maurício Furtado; http://lattes.cnpq.br/7497951647889934; https://orcid.org/0000-0002-1762-8617
The facade maintenance process is guided by the results obtained in the inspection phase. Some proposals for methods aimed at improving the inspection process have been discussed, and among these, those that are conducted based on Digital Image Processing (PDI) techniques captured by Unmanned Aerial Vehicle (UAV) stand out. The use of UAVs to capture images on facades streamlines access to the inspected area, and PDI techniques help to automate the process of identifying pathological manifestations. In addition, the fourth industrial revolution has allowed the use of various technological tools in the most varied engineering applications. Among these technologies we can mention cloud computing and computer vision algorithms. In this context, this research aims to apply PDI techniques to detect regions with ceramic displacement on building facades using technologies relevant to industry 4.0 (fourth industrial revolution). The methodological procedure used starts with the formation of a database (images) captured by cell phone and UAV. For modeling purposes, the YOLO (You Only Look Once) object detection algorithm was applied to the images that make up the database using cloud computing. The applied methodology resulted in a program written in python capable of identifying the regions with displacement, quantifying the missing ceramics and exporting the quantification results in a spreadsheet. The identification process had success rates close to 99% and the quantification errors of less than one ceramic per image, which leads to the conclusion of the feasibility of the proposed computational program