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Acesso aberto (Open Access)
Análise do comportamento de 3 pontes mistas em obras rodoviárias sujeitas à prova de carga estática
(Universidade Federal do Pará, 2023-03-01) SILVA, Paulo Roberto Fontes da; PEREIRA FILHO, Manoel José Mangabeira; http://lattes.cnpq.br/4765401390604065; https://orcid.org/0000-0001-9622-3863; LIMA NETO, Aarão Ferreira; http://lattes.cnpq.br/0287664572311345; https://orcid.org/0000-0002-5911-1368
Along the BR 230/PA, some bridges had their constructions interrupted about 20 years ago, and with the purpose of providing evaluation criteria to the works of road bridges with mixed structure in steel and concrete is proposed the methodology above. As acceptance criteria, static load tests were used in road bridges with mixed structure through characteristic tests, through instrumentation using strain gauges and LVDT's (Linear Variable Differential Transformer), defining displacements and deformations in the structural elements of the OAE (Special Artwork Bridge), with subsequent computational modeling of the structural model of the bridge, aiming to evaluate the performance of the bridges in service, as established in the structural modeling to the core of the OAE project, which were sized for a type train TB-45 (Type Vehicle of 450 kN of total weight),, according to NBR 7188 (2013). To monitor the displacements, LVDT's were used, positioned in the middle of the span and 1/4 of the span of the central stringers, as well as the strain gage allocated in the steel beams, brace and in the CA-50 steel bars of the pillars with verification of the deformations of the referenced structural parts. As results, an evaluation of the service conditions of the bridge was performed, compressing the experimental results of the static load tests with the theoretical-computational predictions in order to validate the models used, in general, the experimentally observed deformations were less intense than the theoretical estimates. This fact corroborates the agreement with the greater rigidity of the structural elements, validating the experimental results, because they presented behavior similar to the theoretical one, however in lower intensity of the OAE's studied. Thus, the experimental and theoric-computational results were compared with the international norms being the ratios of maximum displacement, residual displacement and deformation. The experimental response showed similar behavior, for the bridges over the Arataú, Anapú and Poraquê rivers, to the theoretically predicted. Inaddition to international norms, the results were divergent, especially in the Turkish, Spanish and German countries, and the boundary conditions imposed on the norms should be imposed.
Acesso aberto (Open Access)
Análise experimental do desempenho de conectores de cisalhamento de vergalhões dobrados para estruturas mistas via ensaios push-out
(Universidade Federal do Pará, 2022-11-25) SOUSA, Vanessa Carolaine de; LIMA NETO, Aarão Ferreira; http://lattes.cnpq.br/0287664572311345; https://orcid.org/0000-0002-5911-1368
Advances in civil engineering have led to the development of new techniques and materials that optimize the construction process. In this context, steel-concrete composite structures have emerged, which use steel and concrete efficiently through the collaborative work of the materials, exposing the metal part to tensile stresses and the concrete to compressive stresses. Shear connectors are essential in steel-concrete composite structures. They ensure the interaction between the materials and the transfer of stresses, making the structures lighter, stronger, and more durable. It is important to understand their operation and to seek new materials and technologies to optimize the structures. In this sense, this research continues the work of Souza (2019) and Barbosa (2016), who studied shear connectors made with CA-50 steel bars bent. The experimental program includes 7 models (varying the bar size, reinforcement rate, and the inclination of the connectors relative to the table of the metal profile) that were tested according to the recommendations of Eurocode 4 (2004). Of these 7 models, 2 were made with 12.5 mm rebar (models A1 and A2), 2 with 10.0 mm (models B1 and B2), 2 with 8.0 mm (models C1 and C2), and 1 model made with 6.3 mm diameter assembled in a single module (model D). When analyzing the load-carrying capacity/steel area ratio of the connectors, the results show that connector A1 (12.5 mm) had the best performance among the models in the study and also stands out when compared to other connectors studied such as those of Barbosa (2016), Souza (2019), and Chaves (2009). No significant evidence was observed that the inclination of the connectors positively affects the load-carrying capacity of the models. Analyzing the relative displacement between the profile and the slabs, it was possible to classify the models by ductility, in increasing order: D, A1, C1, C2, A2, B2, and B1. The 10.0 mm models have the highest ductilities, and the influence of the inclination of the connectors on this aspect is not clear. Analyzing the behavior in relation to uplift, it is noted that the best performances are in connectors B and C (10.0 mm and 8.0 mm) and there is a tendency for worse results in inclined connectors.
Acesso aberto (Open Access)
Análise experimental do desempenho de conectores de cisalhamento feitos em aço CA-50 para uso em estruturas mistas de perfis em aço e concreto armado
(Universidade Federal do Pará, 2019-10-25) SOUZA, João Pedro Nascimento de; LIMA NETO, Aarão Ferreira; http://lattes.cnpq.br/0287664572311345; https://orcid.org/0000-0002-5911-1368
The steel and concrete composite structures began to increase as a construction system over the years, due to their advantages both in their structural behavior and in their constructive aspects. These structures are those in which both materials (steel and concrete) work together, and for this to be possible, it is necessary to use connectors that combat the shear forces generated between the materials. There are several types of these connectors, but their goal is to make the structure solid and work monolithically. This work aims to experimentally analyze the performance of shear connectors, for use in steel and concrete reinforced composite structures, modifying geometries and arrangement of connectors composed of Ø 12.5 mm diameter CA50 steel bar bent in shape close to a truss, making a comparative to define which model offers the greatest contribution in the connection. Therefore, push-out tests were performed, following the procedure described in the European Standard Norm EN 1994-1-1 (2004), in 7 specimens, consisting of an 800 mm high welded I-metal profile, and two slabs of reinforced concrete, with dimensions of (600x600x150) mm, in contact with the top of flanges of the metallic profile, containing the welded connectors. Among the 7 models, 2 of them, named Isósceles Truss (IT) and Rectangular Truss (RT), were used as reference; in 4 of them were made variations on the arrangement of the connectors used on the reference specimens, which were named Slanted Isosceles Truss. (SIT), Slanted Rectangular Truss (SRT), Piramidal Isosceles Truss Type A (PIT A) and Piramidal Isosceles Truss Type B (PIT B), and in 1 was made a change on the geometry, which was named Straight Truss (ST). Regarding the load capacity, the ST connector presented a load gain of 10.82%, 32.94%, 19.53%, 34.51%, 30.98%, 23.14 % in relation to IT, RT, SIT, SRT, PIT A and PIT B, respectively. Taking into account the design resistance calculation (𝑃𝑅𝑑) of each connector according to EN 1994-11 (2004), the tested connectors had a load capacity 46.54% higher than 𝑃𝑅𝑑. The connectors, in their entirety, presented themselves as they are ductile in their breaking mode. Compared to the others, the RT connector presented a more rigid, and, the SRT, a more flexible behavior. Thus, it is observed that the proposed connectors presented a good performance in relation to the load capacity and rupture mode.
Acesso aberto (Open Access)
Análise modal operacional: um estudo de caso da influência da alvenaria no comportamento dinâmico de prédios altos
(Universidade Federal do Pará, 2020-08-31) BORGES, João Pedro das Chagas; PRAZERES, Plínio Glauber Carvalho dos; http://lattes.cnpq.br/6175760351403329
Operational modal analysis consists on the modal parameters identification of a given structure from its normal operating conditions and is a reality in engineering applications, in line with the need for more precise and bold methods of structural monitoring. This dissertation aims to study and describe civil engineering structures operational modal analysis and, from its application, to study the masonry influence on the tall buildings dynamic behavior. In order to achieve the objective, two wellknown operational modal analysis methods were used as described in the text and it was showed that it is an important, viable and accurate tool for the Civil Engineering structures dynamic behavior identification. A sixteen-story building in the city of Belém-Pa was analyzed, before and after the masonry panels execution. Here consists the novelty in this work since it is very difficult to find building construction were the masonry is executed in the final construction stage only, what explain the lacking of studies with such characteristics. The study consisted on two measurement campaigns on four of the building's sixteen floors, with three points measure on each of these floors. The EFDD, in the frequency domain, and SSI, in the time domain, operational modal analysis methods were described and applied in the building modal identification in both campaigns. Satisfactory results were achieved and they were validated by the MAC coefficient. The identified natural frequencies had increases in a range from 25% to 35% in the masonry executed structure in relation to the reinforced concrete porch without masonry, which is structure's stiffness gain evidence. In addition, it was observed that this stiffness gain is considerably greater in one of the building's bending directions, indicated by a modal shapes inversion between the first two vibration modes when compared the two campaigns. Through these results, it was concluded that the masonry had significant interference in the building dynamic behavior.
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)
Concreto reforçado com fibras de bambu (Dendrocalamus Giganteus)
(Universidade Federal do Pará, 2019-11-14) FERNANDES, Robson da Silva; PICANÇO, Marcelo de Souza; http://lattes.cnpq.br/4535052395600357; https://orcid.org/0000-0001-7313-1229
Vegetable fibers appear as an alternative to manufacture structural elements in relation to metal and synthetic fibers that have high costs, also causing pollution to the environment due to their manufacturing process. This study analyzes the results of mechanical tests of a fiber reinforced concrete of bamboo bark (Dendrocalamus Giganteus), for use in cementitious plates, obtained experimentally in cylindrical and prismatic specimens according to ABNT standards and international recommendations. Composite traces were determined by means of a pilot study, 1: 2.12: 2.88: 0.58 using the CP-IV pozzolanic cement. The experimental program consisted of a 25 MPa Fck reference concrete and three dosages corresponding to 0.5%, 1.0% and 1.5% by volume of bamboo fiber to the concrete mass, forming four dosages in total. After curing, according to NBR 5738 (2003), prismatic specimens were tested for flexural tensile strength according to NBR 12142 (2010) / JSCE-SF4 (1984) and cylindrical specimens to evaluate the strength. from CRB to axial compression, according to NBR 5739 (2018), to diametric compression tensile, according to NBR 7222 (2011) and static modulus of elasticity, according to NBR 8522 (2008). In the axial compression test the presence of bamboo did not provide an increase of resistance in relation to the reference concrete. However for the tensile and flexural strength, the mixing with the addition of bamboo fiber generated a strength gain of 7% and 9%, respectively, compared to the concrete without addition. It can be concluded that insertion of fiber from bamboo bark increases the tensile strength of the composite.
Acesso aberto (Open Access)
Desempenho estrutural de blocos, primas, mini-paredes e paredes de alvenaria estrutural confeccionadas com blocos cerâmicos produzidos a partir da mistura de lama vermelha com argila
(Universidade Federal do Pará, 2014-03-27) COSTA, Diogo Henrique Pereira e; MACEDO, Alcebíades Negrão; http://lattes.cnpq.br/8313864897400179
New techniques for the improvement of residues have become increasingly important in constructions, especially when it comes to the use of residue from other industries and the reduction of natural raw materials. The objective of this study was to evaluate the use of a residue from the production of metallurgical alumina known as red mud (RM), the structural performance of blocks, prisms, mini-walls and walls made of ceramic blocks with reticulated and circular cross sections, produced from the mixture of clay and RM. Experimental tests were performed corresponding to the characterization of the materials used and testing of compressive strength of units, blocks, prisms, mini-walls and walls. All materials and units met the standard requirements for their correct use in experimental tests. The results of compression tests have shown that elements of the blocks made by mixing clay and RM parameters met the standards and showed satisfactory and superior results to the components made of composite ceramic blocks with 100% clay, usually employed in constructions.
Acesso aberto (Open Access)
Desenvolvimento de um programa para análise não linear geométrica e física de treliças planas através da formulação co-rotacional
(Universidade Federal do Pará, 2015-08-31) SILVA, Tiago Rodrigues da; SOUZA, Remo Magalhães de; http://lattes.cnpq.br/1995895693959225
In this work, we carried out a study on the physical and geometrical non-linear structural analysis of plane trusses in co-rotational formulation. For the purposes of this analysis, it elaborated a computer system for teaching purposes. This paper presents the key simplifying assumptions of the problem and demonstrating all the equations governing the problem. To consider the nonlinear behavior of the material, constitutive equations of hyperelastic material were used, and the constitutive equations of Menegotto and Pinto model. Computational implementation phase we used the Matlab programming language, with general concepts of object-oriented programming. To validate the program, we compared the results obtained through this system to the available literature. In these validation tests and examples, it has proven efficacy and applicability of algorithms implemented in the analysis and its practicality in the use, it is possible to use the computer system for teaching and nonlinear analysis of plane trusses.
Acesso aberto (Open Access)
Eletroquímica coloidal e sua relação com a sensibilidade de um solo argiloso na foz do rio Amazonas
(Universidade Federal do Pará, 2023-06-29) SOUSA, Flaviany Luise Nogueira de; TEIXEIRA, Marcelo Rassy; http://lattes.cnpq.br/8912916360456192
Clays have always played an important role in the history of civilizations, mainly because they are a mineral resource with varied technological applications. Among the several existing types, sensitive clays (quick clays), for example, are very complex soft soils that are considered real challenges for engineers due to the difficulty in obtaining their geotechnical parameters. In this sense, the aim of the present study was to analyze the sensitivity of a clay soil found in a region of the city of Santana, in the state of Amapá, Brazil. To this end, physical and chemical tests were carried out, including the SPT (Standard Penetration Test), X-Ray Diffraction (XRD), Zeta Potential (ζ), pH, Cation Exchange Capacity (CEC), as well as resistance assays (Vane Test and Fall Cone Test – FCT). The analyzed area is located in the Macapá Fluvio-marine Plain, which is composed of sediments that were deposited both by rivers and by the sea as a result of the region’s proximity to the mouth of the Amazon River. The geological profile obtained through geotechnical investigation indicated that the soil is constituted of mottled sandy-clay sediments, sandy-silty sediments with plant remains, and sandy- silty sediments with pebbles. As for the mineralogy of the samples, they were essentially composed of quartz and three clay minerals: kaolinite, mica/illite, and chlorite. Regarding sensitivity, all samples were classified as quick clays, with medium or high amounts of organic matter (O.M.); greater organic matter content was associated with increased sensitivity. In addition, it was understood that the intensity of clay sensitivity was higher with the increase in monovalent cations and the decrease in divalent cations such as Ca2+ and Mg2+, which must have been removed by the O.M. The soil pH reading ranged from high to very high acidity, an expected classification due to the increase in H+ concentration due to the O.M. All samples showed similar ζ values, with the lowest being 31.3 mV and 33.2 mV, which are still considered high, indicating that the soil colloids repel each other, forming a dispersed structure. Our results were consistent with similar reports in the literature; however, regionalized studies are necessary for a better understanding of the local peculiarities capable of influencing the profile of this soil.
Acesso aberto (Open Access)
Estruturas portuárias: distribuição de esforços na infraestrutura devidos à amarração e atracação de embarcações
(Universidade Federal do Pará, 2015-03-26) COMIN, Cristiano; SOUZA, Remo Magalhães de; http://lattes.cnpq.br/1995895693959225
This work presents a study on the design loads due to mooring and berthing of vessels, regarding the design and analysis of port structures. A literature review was conducted, with emphasis on technical standards and codes, encompassing both national and international publications. More specifically, this study considered design recommendations of the Brazilian Standard NBR 9782/1987, the British Standard BS 6349 and the German Standard EAU 2004, in addition to the recommendations of the Permanent International Association of Navigation Congresses (PIANC 2002) and the analysis procedure proposed on the book “Port Works” by Jayme Mason (1982). The design procedures proposed by these different references regarding the computation of forces due to mooring and berthing of vessels where evaluated in this work. Later, a case study of a port’s substructure was carried on, and a comparative analysis of the results, obtained with each recommendation of the aforementioned publications, was performed. Results showed a remarkable dispersion, revealing a strong influence of the standard to be used in the design loads of port structures.
Acesso aberto (Open Access)
Impacto da inércia de seções retangulares e do consumo de fibras na resposta estrutural de vigas contínuas em CRFA solicitadas por carga distribuída: campanha experimental
(Universidade Federal do Pará, 2023-01-25) MONTEIRO, Paulo André dos Santos; MORAES NETO, Bernardo Nunes de; http://lattes.cnpq.br/5790058515094077
In order to play up the proper selection of rectangular section inertia on flexural design of steel fibre reinforced concrete beams, SFRC beams, an experimental campaign has been introduced. Presently, four beams have been tested, where the reference one, with cross section of 150x300 mm2, was in reinforced concrete, RC, and three beams were in SFRC. The rectangular section inertia judgment was on SFRC beams only, where their cross-sections varied in 150x300, 110x400 and 90x500 mm2. The cross-section areas of those beams were constants and their fibre contents were 75, 60 and 45 kg/m3 on concrete volume, respectively. Under those circumstances, the conventional reinforcement arrangements, i.e., steel rebar details, were alternated as well as suppressions were also executed on SFRC beams. Nevertheless, all SFRC beams have carried the reference strength, which meant, the RC beam strength. In addition, it is worth mentioning that all questions called before were carried on continuous beams, where normal and transverse stresses are concomitantly relevant, under uniformly distributed loading. As a conclusion, the results have shown the effectiveness of steel fibres, as a reinforcement alternative, and the advantages of a proper inertia in design issues, warranting the reference strength, even using less reinforcement, both rebars and fibres. Now, concerning to design guidelines, MC10 (2013) proposals have been handled. Herein, applying those letters of support, an interactive methodology was introduced to figure out the flexural strength of RC and SFRC beams, taking, at the same time, all description of reinforcement influence, longitudinal/transverse rebars and fibres. To conclude, in order to improve, in the future, the design of continuous beams uniformly distributed loading, some advices have also been announced.
Acesso aberto (Open Access)
Mapeamento das fundações mais usadas na cidade de Belém-PA: aspectos gerais e proposta preliminar de mapeamento de soluções utilizadas em casos recentes
(Universidade Federal do Pará, 2003-03-21) SALAME, Antonio Massoud; ALENCAR JÚNIOR, Júlio Augusto de; http://lattes.cnpq.br/3663658632717465
Accomplishes the survey of the most commonly types of foundations used in the construction work, in the last decades in the city of Belém-PA; defining its characteristics, peculiarities, technical aspects of the its measurement, load capacity and, executive process. Identifies the type of the soil in which are laid with respective profile and geotechnical characteristics and divides the city into areas, mapping according to its geological profile; type of foundation; layer depth; executive process and, relative cost. The work is divided in four stages: the first one corresponds the literature review, regarding the study of the foundations, including the foundation historical development and soil mechanics in the world, in Brazil and in Belém; geotechnical research with characteristics of the soil in the area of Belém and, study of the Geographical Information Systems GIS. The second stage involving technical survey in construction and design companies, for development of database concerning the foundations used in the city. The third, to relates the ordination and technical analyses of the collected data and, the fourth consists on the writing of the final text and the elaboration of the city maps, based on the Geographical Information Systems GIS, in scale 1:10.000, concerning the type of foundation; the geotechnical profile of the soil; the soils kind and the executive process; the probable foundation depth and, the relative cost of the foundation in relation to the total of the work.
Acesso aberto (Open Access)
Viabilidade estrutural dos blocos em concreto vazado produzidos com agregados da região do baixo amazonas estado do Pará, para a utilização em alvenaria estrutural
(Universidade Federal do Pará, 2017-03-13) SILVA, Hugo Ricardo Aquino Sousa da; MACEDO, Alcebíades Negrão; http://lattes.cnpq.br/8313864897400179
This study aims to analyze the performance of blocks, prisms and Mini Structural masonry walls made from blocks produced with Concrete aggregates baixo amazonas Region. This region of the baixo amazonas has a number of types of materials that can be used in conjunction with other aggregates, the manufacture of concrete blocks for use in structural masonry. The construction of buildings with structural use of concrete blocks is growing considerably across the country. This study focuses attention on the city of Santarém and nearby towns in order to characterize the structural form and map the aggregates for the production of concrete blocks. In the city of Santarém and municipalities around thus considered baixo amazonas, many households are being used for the production of mortar and concrete, either dry or conventional. There is still no evidence about their effectiveness and efficiency. This work was performed in order to obtain greater insight into the structural masonry type of construction that is reclaiming its space in the building sector. In materials and methods to be employed in this certification testing of prisms and walls will be conducted using concrete blocks and aggregates of the baixo amazonas region.