Mestrado em Engenharia Civil (EEC)

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Análise do comportamento de pilares de concreto armado reforçados com chumbadores e concreto auto adensável
(Universidade Federal de Goiás, 2014-04-11) Marques, Marília Gonçalves; Liserre, Andrea Prado Abreu Reis; Gomes, Ronaldo Barros; http://lattes.cnpq.br/6046088082653028; Gomes, Ronaldo Barros; Liserre, Andrea Prado Abreu Reis; Guimarães, Gilson Natal; Trautwein, Leandro Mouta
Strengthening of reinforced concrete columns by jacketing is one of the most common structural rehabilitation techniques in Brazil. For adequate performance, it is necessary, among others, to avoid detachment of the new concrete layer (strengthening material) from the old concrete substrate when the strengthened member is again in service conditions. This paper describes the test results of eight reinforced concrete rectangular columns subjected to combined compression and one-axis bending to evaluate the efficiency of using sleeve wedge bolts across the new concrete/old concrete interface to avoid detachment. The strengthening technique, in this case, consisted of adding a layer of self-compacting concrete to one column face. Two columns tested were monolithic and named PO (original column) e PR (reference column). The other six columns were strengthened using a new 35 mm thick self-compacting concrete layer attached to the column face subjected to highest compressive stresses. Column PO had a 120mm by 250 mm rectangular cross section and its results gave information about column behavior without the use of strengthening. Column PR had a 155mm by 250 mm rectangular cross section and its cross section dimensions matched the strengthened columns but it was cast monolithically. To improve bond conditions between the existing concrete and the new concrete, the concrete surface was roughened and the outermost aggregate was exposed using hydro jetting. Holes along the concrete surface were made to insert the wedge bolts responsible for increasing the bond between the two concrete surfaces. The difference among the six strengthened columns consisted in the position and amount of bolts used. Results indicate the position and amount of the bolts significantly alters the strength capacity of the strengthened columns since premature rupture by concrete detachment was delayed. The reinforcement used was increased approximately three times the ultimate load of the original column, indicating the good performance of reinforcement.
Análise experimental da resistência à flexão simples de vigas de aço tipo "I" compostas de perfis laminados dotadas de emendas soldadas
(Universidade Federal de Goiás, 2015-02-04) Borges, Rone Sergio Freitas; Gomes, Orlando Ferreira; http://lattes.cnpq.br/3244852416821211; Gomes, Orlando Ferreira; Silva, Wellington Andrade da; Liserre, Andrea Prado Abreu Reis
In Brazil, despite the skilled labor shortage, the use of metal structures in buildings has increased considerably due to factors such as speed of execution, cleaning the construction site, low deadweight compared with reinforced concrete structures, low material waste, etc. For better utilization of equipment and for which continuity of the openings is necessary to use the amendments, which can be welded or screwed. The quality of the amendments must meet the standards required by the design standards, in rolled profiles, according to ABNT NBR 8800:2008 (Steel Structures Design and Composite Structures of Steel and concrete buildings). These profiles have great applicability in large structures and their use is growing in buildings with these characteristics. This paper presents the experimental study of bearing capacity of two beams supported by steel made of rolled profiles section I of type W 250 x 22,3 ASTM A-572, grade 50, rolled parallel flaps with two axes of symmetry, being provided splices using full penetration welds MIG type (Metal Inert Gas). Seven beams were tested with a length of 3000 mm, with a reference beam. In the remaining six beams amendments were made in different positions varying the amount of amendments. This study also provides a comparison between the results obtained in this work and those obtained by Pereira (2014), which used beams with bolted connections using the same provisions of the amendments of this work, but with ASTM A-325 and screw diameter of 19 mm. All models have been requested by simple bending stress at break, according to the analysis of vertical displacement, and torsional displacement relative specific deformations steel. The connections of beams resisted the simple bending tests not being observed no break in welds. The main contribution of this work was to show that, if well executed, welded connections and bolted performed by Pereira (2014), with the specifications described in this paper, can be used as elements of connections in steel beams subjected to bending, as well resisted the requested efforts .
Análise experimental de pilares de concreto armado submetidos à flexo-compressão, reforçados com comcreto auto-adensável e chumbadores
(Universidade Federal de Goiás, 2008-10-28) SAHB, Keyla Fabrícia Pereira; SHEHATA, Ibrahim Abd El Malik; http://lattes.cnpq.br/5739886256942536; GOMES, Ronaldo Barros; lattes.cnpq.br/6046088082653028
The reinforced concrete structures are subject to interference from many factors that affect its stability and its performance and may generate the need for interventions and eventual reinforcement. There are several techniques of enhancing that can be employed and in the case of columns, the increase of the section with reinforced concrete is quite usual. This type of enhancement requires the attendance requirements to ensure its effectiveness, among which stand out in importance: meeting the needs and characteristics of project, the appropriate sizing, and the adhesion between concrete of different ages. Although the reinforcement of structures involve risk situations, and in many cases, are costly and uncertain, does not exist in the country a specific normalization for their specific design and implementation, thus they have been executed considering the normative disposals for project and execution of structures of armed concrete and in personal experiences. This research was evaluated the behavior of reinforced concrete columns required to flexural compression, with an initial section of 120 mm x 250 mm and height of 2000 mm in the compressed section and enhanced with a layer of 35 mm of self compact concrete and anchors. Was varied the amount of anchors and kept the other variables such as the concrete strength of the original columns and the enhanced columns, the initial rate of reinforcement, the eccentricity of the load test, the thickness of the reinforcement and the preparation of the substratum method. The strengthened columns had presented increasing load by increasing the amount of anchors used in the interface between the concrete of different ages. The improvement in the performance of the interface was observed, slowing the sputting and in one case, the column with a larger amount of anchors, with the crushing of concrete and sputting, almost simultaneously. There was a reduction of displacements caused by the decrease in ductility. These evidences indicate that the adopted technique of reinforcement if showed efficient, promoting consolidation of the composed section better
Análise experimental de pilares de concreto armado submetidos à flexo-compressão, reforçados com concreto auto-adensável e conectores
(Universidade Federal de Goiás, 2009-09-11) NASCIMENTO, Poliana Paula; GOMES, Ronaldo Barros; lattes.cnpq.br/6046088082653028
Many problems involving cases of ruins of buildings, bridges, etc., specifically ruin of columns, which are among the most important links in the whole structure, due to project flaw, bad execution or even for the evolution and changing habits. Therefore it has been of fundamental importance researches on the experimental behavior of structures. When conducting a strengthening column using dry with increased self-compacting concrete, it has the drawback of a sudden rupture by peeling the reinforcement. For this, there is a need to study the area of adhesion between substrate and to strengthen and create a way of preparation of this interface area so that the column increases may come into ruin in a ductile flexural as well as in a monolithic column. Thus, it s been developed an experimental study in the School of Civil Engineering, Federal University of Goias, based on analysis of the breaking loads, lateral displacements and deformations of the column of materials for different ways of preparing the surface of the column to be strengthened. The experimental phase of this work was based on testing of nine reinforced concrete columns, which are tested under flexural compression, with eccentricity of 60 mm. Two columns were used as reference columns, one with the original dimensions of the column and the other monolithic concreted in the thickness of a sin reinforced the others received a layer of 35 mm thick concrete selfcompacting in the compressed face. For preparation of the interchange between the two materials, it was proceeded with the scarification and the realization of grooves along this surface, where inserted connectors attached to transverse reinforcement of the columns, varying the position and quantity of the same. It can be concluded that not only quantity, but mainly the location of connectors used in the connection between the substrate and reinforcement, is essential for a good result of resistance and rupture mode. Must be observed a minimum spacing between the connectors strengthening to ensure a more monolithic unit, enabling a ductile rupture occurred as the reference column
Análise experimental de pilares de concreto armado submetidos à flexo-compressão, reforçados com concreto auto-adensável e conectores metálicos
(Universidade Federal de Goiás, 2015-11-27) Rocha, Anderson Souza; Delalibera, Rodrigo Gustavo; http://lattes.cnpq.br/6277549281444797; Delalibera, Rodrigo Gustavo; Silva, Wellington Andrade da; Souza Júnior, Dogmar Antônio de
The proposed research is based on the study of reinforcement columms in reinforced concrete, with the use of anchor bolts and fill with self-compacting concrete, by jacketing. In addition to the experimental studies, numerical simulation was performed using a computer program based on the finite element method, took into account the breaking loads, displacements and deformations which allows a careful study of reinforced columms. The experimental part of this work was based on the test five columms of reinforced concrete, submitted to straight flexion-compression, in order to assess the bond interface between the concrete substrate and reinforcement of concrete and confirm the efficiency of this technique commonly used for reinforcement. Two columms were used as reference, one with the original abutment dimensions (Reference Columm, cross section: 120 x 250 mm) and the other monolithic concreted with the section of enhanced piece (Monolithic Columm, cross section: 155 x 250 mm). The others received a layer of 35 mm thick concrete in the compressed self-compacting face. The preparation of the interface between the two materials, it will be carried with the scarification boreholes along this surface, which anchors were inserted responsible for reinforcement of concrete bond with the substrate. It can be concluded on the work developed that not only the quantity but especially the location of the connectors used for the connection between the two materials, are essential for a good result of resistance and failure mode. Despite the studs do not present break, there was the peeling of the reinforcement layer. The results obtained indicate the possibility of using this method in the structural reinforcement columms rehabilitation, as it showed an increase in bearing capacity of about four times compared to the column of reference. The results of numerical simulation were very satisfactory, because the behavior of the columms in relation to tensile strength, displacements and deformations, approached the experimental results, with minor differences.
Análise experimental de pilares de concreto armado, com carga excêntrica, reforçados com chumbadores e concreto autoadensável (CAA)
(Universidade Federal de Goiás, 2015-10-16) Virgens, Jeovan Pereira das; Trautwein , Leandro Mouta; http://lattes.cnpq.br/8892009084347857; Gomes, Ronaldo Barros; http://lattes.cnpq.br/6046088082653028; Gomes, Ronaldo Barros; Trautwein, Leandro Mouta; Guimarães, Gilson Natal; Vaz, Ana Paula Rodrigues
This paper presents the experimental study of reinforcement concrete columns reinforced with wedge bolts and a 35 mm self compacting concrete jacket at the most compressed face. Nine columns with a 2000 mm height subjected to flexure and bending with initial eccentricity of 60 mm, named as: original column (Po) with a cross section of 120 mm x 250 mm; reference column (Pref) with a cross section of 155 mm x 250 mm and seven columns with a initial cross section of 120 mm x 250 mm, and later reinforced by the addition of 35 mm reinforcing layer, and various configurations of wedge bolts at its most compressed face. Except for the original column (Po), the columns were submitted to a 42.5 mm load eccentricity due to the attached concrete layer at the compressed face. Although failure of the wedge bolts did not accour, it was not possible to prevent detachment of the reinforcing layer. The results indicate that it is possible to structural rehabilitate reinforce concrete columns with the use of the strengthening methodology used in this research, resulting in average load capacity gains of 3,71 times compared to original column load (Po).
Análise experimental de pilares de concreto armado, reforçados com concreto auto adensável e conectores
(Universidade Federal de Goiás, 2014-05-12) Ferreira, Diego Borja; Carvalho, Alessandra Luciano; Gomes, Ronaldo Barros; http://lattes.cnpq.br/6046088082653028; Gomes, Ronaldo Barros; Carvalho, Alessandra Luciano; Oliveira, Janes Cleiton Alves de; Melo, Carlos Eduardo Luna de
Studying strengthening in reinforced concrete structures is an ever-growing necessity in civil construction. Flaws during design, execution, use, and maintenance, as well as the use of poor quality construction materials and a structure's functional change may all lead to this necessity. Strengthening a given structure is justified whenever it becomes necessary to increase its bearing capacity. The small number of studies which analyse the behaviour of strengthened structures makes it difficult to establish parameters that may contribute to designing such projects. This research assessed the behaviour of reinforced concrete columns under compression and one-way eccentricity, with an initial section of 120 mm x 250 mm and height of 2000 mm, strengthened in the compressed area with a 35 mm layer of self-compacting concrete. Connector screws were used as interaction reinforcement. The main variables were the connectors' position and steel rate. Strengthened columns showed an increase in rupture by approximately three times load due to the increase of connectors' rate. One of the problems detected was the concrete reinforcement layer spalling near the rupture load, whose solution requires further research. There was also a reduction in columns' horizontal displacements, caused by a decrease in ductility. These results show the effectiveness of the strengthening technique employed.
Análise experimental de vigas constituídas de perfis formados a frio com emendas soldadas submetidas à flexão simples
(Universidade Federal de Goiás, 2009-09-23) ALMEIDA, Ariovaldo Fernandes de; GOMES, Orlando Ferreira; http://lattes.cnpq.br/3244852416821211
The cold-formed steel sheets have been sufficiently used when it is thought of manufacturing a metallic structure with reduced weight. Its use until some time ago in construction was limited to the secondary structures, but, with considerable growth in research involving this type of material together with development of technical standards, made its use a good solution for certain types of light structures. The present work presents considerations on cold-formed steel sheets, the patened steel, processes of welding and the result of experimental tests with beams with composed section of two profiles U constituted with cold-formed steel sheets, manufactured with two types of patened steel produced in Brazil. In some of these beams, welded sections with coated electrode had been used and were made the comparison with the reference beam, where it was possible to study the influence of the process of welding in the ultimate resistance and the ductility of the beam.
Análise experimental de vigas de seção I compostas de perfis formados a frio com emendas soldadas, submetidas à flexão simples
(Universidade Federal de Goiás, 2010-03-19) VIEIRA, Gregório Sandro; GOMES, Orlando Ferreira; http://lattes.cnpq.br/3244852416821211
This paper presents an experimental study done in bi-metal beams supported from 3000 mm in length, composed of thin-walled, resulting in a section of the "I". The beams were formed from the welding of the souls of two metal profiles of type U. The variables were the type of profile used, the quantity and positioning of the welded seams. The beams were divided into two groups where the first group used profiles of the "U" and the second group used simple profiles such as "U" stiff. Each group was composed of three beams so that a beam does not receive any amendment, another amendment received a girder high up in the middle of the span, and the third top beam was amended so that the position would result in an amendment pierced. The applied load was set so as to leave the central part of the beams, which served as a region of the present study, working in pure bending. Test results for beams without amendment were compared with the theoretical results and served as a parameter to compare the behavior of these beams, with beams that were amended. Also a comparison was made between the bearing capacity of the two groups of beams. The experiments showed that, by making the proper control of welding there is no problem in making welded seams in the rafters. We also observed that the simple addition of stiffening beams tables promotes a significant increase in the bearing capacity. There was no correlation between failure modes provided theoretically and observed experimentally, thus, further studies are needed to properly analyze the theoretical results with experimental results.
Análise não-linear de lajes de concreto armado pelo método dos elementos finitos
(Universidade Federal de Goiás, 2006-09-27) BANDEIRA, Mirtes Silva; PRADO, Ademir Aparecido do; http://lattes.cnpq.br/4118518363912053
In this work was carried simulations in the slabs and compared results with those obtained in the experimental research of Campos (2000) and Pires (2003), held on the slabs reinforced concrete brought to the failure by bending for inquiry of strengthening using uper the surface. For the modeling version 8.1.2 of DIANA was used and the inquiry of the behavior of the slabs was made through nonlinear analysis, adopting for the models elements of shell and solid. The behavior of the slabs was analyzed through the displacements central and approached the influence of the positioning of the reinforcement, the supports and the parameters that define the behavior of the concrete in the softening phase, being distinguished it maximum resistance of the concrete in the tension. The results are indicative of the good performance of the applied numerical models and that, the programs that use the concepts of the Fracture Mechanics in its formularizations, consist in powerful tool to reduce the amount of tests for the study of some specific phenomena, since that if they have resulted trustworthy of the behavior of the employed materials.
Análise numérica da cravação estática de estacas metálicas tubulares de ponta aberta
(Universidade Federal de Goiás, 2018-06-29) Ferreira, Jaqueline Rodrigues; Vargas, Carlos Alberto Lauro; http://lattes.cnpq.br/3816106720170772; Sales, Maurício Martines; http://lattes.cnpq.br/2033708685029423; Sales, Maurício Martines; Cavalcante, André Luís Brasil; Gitirana Junior, Gilson de Farias Neves
The use of steel pipe piles as a foundation element brings a new focus to the contributions of soil plug to the behavior of open-ended pipe piles. Therefore, considering the necessity to understand the plug formation, its influence on pipe pile load capacity and the limited of research developed in real scale models, this work aims to numerically simulate the process jacking open ended steel pipe piles in sands, seeking to investigate the soil properties and piles geometry interference on the jacking process. For the development of these simulations an explicit finite difference program, FLAC (Fast Lagrangian Analysis of Continua), was used. The methodology developed started with the finite difference mesh, jacking velocity and interface parameters (normal and shear modulus) calibration. This process was validated with calibration chamber tests results developed in other researches. Henceforth, parametric analysis involving the pipe geometry – internal diameter, wall thickness and tip angle – and the soil mechanical parameters – friction angle, density and elastic modulus – were conducted. As result, among all the factors analyzed, soil density and pile tip angle do not interfere in soil plug formation. Furthermore, the program selected for the simulations was able to model plugging, exhibiting similar behavior to calibration chamber tests results.
Aplicação do polinômio de Hermite-Caos para a determinação da carga de instabilidade paramétrica de cascas cilíndricas com incerteza nos parâmetros físicos e geométricos
(Universidade Federal de Goiás, 2014-04-04) Brazão, A. F.; Silva, Frederico Martins Alves da; http://lattes.cnpq.br/9929132527197884; Silva, Frederico Martins Alves da; Del Prado, Z. J. G. N.; Soares, Renata M.; Silveira, Ricardo A. M.
The present study aims to investigate the influence of uncertainties in physical and geometric parameters to obtain the load parametric instability of cylindrical shell, using the Galerkin method with the stochastic polynomial Hermite-Caos. The nonlinear equations of motion of the cylindrical shell are deduced from their functional power considering the strain field proposed by Donnell´s nonlinear shallow shell theory. The uncertainties are considered as random parameters with probability density function known in the partial differential equation of motion of the cylindrical shell, which it becomes a stochastic partial differential equation due to the presence of randomness. First, the discretization of the stochastic problem is performed using the stochastic Galerkin method together with polynomial Hermite-Chaos, to transform the stochastic partial differential equation into a set of equivalent deterministic partial differential equations, which take into account the randomness of the system. Then, the discretization of the lateral field displacement is made by a perturbation procedure, indicating the nonlinear vibration modes which couple to the linear vibration mode. The set of partial differential equations is transformed into a deterministic system of equations deterministic ordinary second order in time. Uncertainty is considered in one of its parameters: the Young modulus, thickness and amplitude of initial geometric imperfection. Then we analyze the influence of randomness in two parameters simultaneously: the thickness and the Young modulus. Once obtained the system of ordinary differential equations deterministic containing the randomness of the parameters, the integration over discrete time system is made from the Runge- Kutta fourth order to obtain results as the time response, bifurcation diagrams and boundaries of instability which are compared with deterministic analysis, indicating that polynomial Hermite-Chaos is a good numerical tool for predicting the load parametric instability without the need to perform a process of sampling.
Avaliação da eficiência do uso de conectores de cisalhamento no reforço de vigas de concreto armado pela face comprimida
(Universidade Federal de Goiás, 2011-06-30) SILVA, Paula Miranda da; LISERRE, Andrea Prado Abreu Reis; http://lattes.cnpq.br/9117996162316382
A structure is designed to have satisfactory performance during its life given the requirements for which it was designed. When performance becomes unsatisfactory, intervention is needed in order to rehabilitate the structure. Structural rehabilitation is characterized by increasing the structure‟s original load bearing capacity. Of the various existing intervention techniques, this work studies the technique that increases the concrete section by adding more concrete to the compression side and evaluates the effectiveness of shear connectors to bond the new concrete to the base concrete. The increase of the concrete section and the layout of the shear connectors were done along the entire length of the beam. There were two test series. In the first test series, called preliminary tests, the variable studied was the type of connector in order to determine which type ("I", "U" or "AF") would present more efficient results. In the second test series we adopted the connector type "I", which showed the best results from the first series. The variables studied in the second series were the shear connector ratio, the influence of pre-cracking and the presence of confining reinforcement in the new concrete region. The surface treatment used was manual blasting without the use of bonding agents. The test results indicated that the presence of shear connectors type "I", a small ribbed reinforcement bar, prevented the loss of bond between the base concrete and the new concrete, prevented splitting of the new concrete cover which was observed in tests with beams reinforced without the shear connectors. Good results were obtained with respect to increased load bearing capacity of the beams, since even the pre-cracked beams gained strength as well as strength increased in non-cracked ones.
Avaliação da qualidade de concretos produzidos em centrais dosadoras, misturados em caminhão betoneira e de concretos produzidos em centrais misturadoras
(Universidade Federal de Goiás, 2009-12-14) BORGES, Michelly Lorena; GEYER, André Bortolacci; http://lattes.cnpq.br/0135796530510700
Due to the small number of studies about the process of production of the concrete dosed in central, as regards the type of employed mixture, this inquiry looked to contribute to the assessment of quality of concrete produced in mixing plant and metering plant. The principal objective of the work was checking if the form of mixing of the concrete can affect your characteristics in hardened state (compressive strength), for that, there was compared the quality of the concrete produced in metering plant and mixed in truck mixer in relation to the mixing plant. As the sample was taken a work, where they had installed a metering plant and a mixing plant, which together produced 300.000 m³ of concrete with the same materials. Inside the proposed objective, also were quantified statistically the existent types of concrete in the same truck mixer, using as the parameter the compressive strength of concrete produced in the metering plant. In the end, it was possible to conclude that the mixing plant produce a concrete of better quality with a less standard deviation than the metering plant. Was also observed a significant variability inside the truck mixer, which made the division of the concrete possible in five group, with different resistances'
Avaliação de trechos de pavimentos experimentais construídos com materiais alternativos na região metropolitana de Goiânia
(Universidade Federal de Goiás, 2012-08-27) Marques, Michelle de Oliveira; Rezende, Lilian Ribeiro de; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4768291J2; Rezende, Lilian Ribeiro de; Gitirana Júnior, Gilson de Farias Neves; Trichês, Glicério
In the Federal University of Goias (UFG) some researches have been developed focus on the importance of the alternative materials study for urban paving in substitution to the traditional materials used in the area, as the lateritic gravel. These studies contemplated the construction of experimental road pavements divided in sections in function of the materials composition used for the subbase and base layers execution, aiming the evaluation of the pavement performance when submitted to the real traffic in roads with low to medium traffic volume. Since 2004, three experimental roads were built, being two in the city of Goiania-GO and one in Aparecida of Goiania-GO. The no conventional and environmental correct materials used in those works were: civil construction waste, quarry waste, phosphogypsum and mixtures of fine soil found at the place of the work with crushed rock or lime. As the periodic monitoring is of great importance for the constant evaluation of the behavior of those pavements, this research had as objective monitors the existent roads in the year of 2011 and to compare the results obtained with the one of the previous studies. For so much, several field tests were done in two different periods: one of dry and other rainy. The field tests were executed with the following equipments: Benkelman beam, plate bearing, Dynamic Cone Penetrometer (DCP) and PenetrometreAutonomeNumeriqueDynamique equal AssistéOrdinatur (PANDA), so much with the cone of 2 cm2 as with the one of 4 cm². Besides, samples of the structural layers of the pavements and subgrades were collected for water content verification in the two periods of tests. At the end of each test the comparison of the roads performance was done along the time from the construction period. In general, it is observed that all the alternative materials used in the experimental pavements have been presenting similar behavior to the lateritic gravel, showing application viability.
AVALIAÇÃO DO DESEMPENHO DE CONCRETOS COM ADIÇÕES MINERAIS QUANTO À CORROSÃO DAS ARMADURAS INDUZIDA POR CLORETOS
(Universidade Federal de Goiás, 2007-08-29) OLIVEIRA, Andrielli Morais de; CASCUDO, Oswaldo; http://lattes.cnpq.br/3336749062812376
The present work aims to study the performance of concrete with regard to the action of chloride ions, evaluating the influence of both mineral additions and water/binder ratio (w/b), considering kinetic and thermodynamic aspects of the corrosive phenomenon. A experimental research was carried out considering the following variables: the presence of mineral additions in partial substitution to the cement weight (10% of silica fume; 25% of fly ash; 10%, 20% and 30% of metakaolin) and the water/binder ratio (0,40 and 0,55). Thus, cubic concrete test specimens were produced, in addition to cylindrical test specimens for concrete characterization in relation to the compressive strength, specific mass, void ratio and capillary water absorption. After 645 days of casting, the cubic concrete test specimens were submitted to the chlorides attack during 308 days, totality 44 weekly cycles of immersion in chlorides aggressive solution. They were monitored, throughout this period, by means of techniques, such as: the concrete electric resistivity, the half-cell potential, the polarization resistance and the electrochemical impedance spectroscopy. At the end of the experiment, visual inspections of reinforcing steels allowed to observe their superficial aspects after attack. As general result, it was gotten that the incorporation of mineral additions to the concretes promoted significant profits in all the evaluated properties, evidencing the beneficial effect of these additions in concretes exposed to aggressive conditions, specially in those in which there are chloride ions. In this direction, the statistical analysis has shown evidences that concretes with silica fume and metakaolin achieved the best results of electrical resistivity. In relation to the half-cell potentials, the reference concrete (without mineral additions) presented the worst performance, with an indication of despassivation in the reinforcing steels accentuated fall in the values of resistance of polarization with the time, proving the susceptibility of these systems to the action of chlorides. The concrete with mineral additions did not present depassivation of the reinforcing steels meaning that these systems possess great durability and service life in relation to those without mineral additions
Busca da superfície de ruptura crítica na análise tridimensional de estabilidade de taludes
(Universidade Federal de Goiás, 2010-08-24) SOARES, Patrícia Maria de Carvalho; GITIRANA JUNIOR, Gilson de Farias Neves; http://lattes.cnpq.br/4710728908810849; ALMEIDA, Sylvia Regina Mesquita de; http://lattes.cnpq.br/1855764480221018
The main objective is to develop, implement and evaluate a method to search for surfaces in order to determine the three-dimensional critical surface, corresponding to the lowest factor of safety of the embankment. They are also objectives of this study to evaluate the influence of the strength and elastic parameters the geometry of the slope safety factor and the 3D shape and position of the failure surface, as well as to evaluate the relationship between 2D and 3D safety factors. It was implemented an optimization routine in FORTRAN that performs the search for critical failure surface, whose safety factor is calculated by SAFE-3D program. The SAFE-3D program uses voltages coming from an elastic stress analysis performed by FlexPDE program, which uses the finite element method and provides the shear and normal stresses acting on the slope necessary to calculate the safety factor. For the analysis has been adopted as the ellipsoid shape of the rupture surface. The search method implemented examines safety factors obtained for a finite set of solutions and design variables as the coordinates of the center of the ellipsoid and the size of its three semi-axes. The search algorithm is implemented in successive tests of the factor of safety by SAFE-3D program, varying the position and dimensions of the ellipsoid for the determination of lower safety factor of slope. It was analyzed two examples of slopes, a symmetrical slope which varied the parameters of soil strength and the angle of the slope face and the other was the historic case of slipping Lodalen. The methodology implemented was successful in finding the critical failure surface, achieving consistency in results. The Poisson's ratio was very influential in the results of the safety factors of three-dimensional critical surfaces. It was also observed that there is less difference between the safety factors when keeping the shear stress unacceptable when these tensions are eliminated there is a closeness among the factors of safety.
Cadastro Geotécnico dos solos finos lateríticos para fins de pavimentação no município de Goiânia- GO
(Universidade Federal de Goiás, 2010-08-24) CARDOSO, Ricardo Alves; ROMÃO, Patrícia de Araújo; http://lattes.cnpq.br/0188184635964559; REZENDE, Lilian Ribeiro de; http://lattes.cnpq.br/9258692609398794
This work aims at the register of geotechnical areas in Goiania-GO, showing the occurrence of fine lateritic soils with potential for use in flooring. The methodology is based on work developed by Nogami and Villibor (1995). From surveys and collecting 17 samples in field tests were conducted from MCT (Mini-MCV, Loss of mass by immersion, compression and Mini-CBR) and verified the mechanical and hydraulic properties of these soils. The samples were collected at sites previously chosen using as reference the pedological map of Goiania, trying to distribute them to all soil units of this map. The surveys were performed to a depth of 2 m in each hole the soils were mixed, representing what occurs in practice during the operation of a loan area. The samples collected for the study were those who had only fine soil grains with diameters of less than 2 mm (sieve nº. 10). Tests were also carried out conventional characterization (particle size, Atterberg limits and specific gravity) of the samples collected to better identify these soils. The results obtained with all samples have the intention to form a database for future research in the area of pavement. It was found that in Goiania most soils are lateritic clay and can be applied in the construction of paviments with low traffic volume.
Comparação experimental entre tipos de armadura de cisalhamento para combate à punção em lajes cogumelo de concreto armado: Stud rails e Double headed studs
(Universidade Federal de Goiás, 2009-09-29) RODRIGUES, David Rosa; GOMES, Ronaldo Barros; lattes.cnpq.br/6046088082653028
This research presents the results of an experimental comparison between the types of shear reinforcement "stud rails" and "double headed studs" to combat the punching shear of a reinforced concrete flat slabs. It also presents a comparison of experimental results with those provided under the ACI 318/2005, CEB-FIP MC/1990, EUROCODE 2/2004 and NBR 6118:2003. The motivation was to investigate the efficiency of these shear reinforcement for the differences between them. It was tested six slabs of concrete to concentric load, with dimensions of 2400 mm x 2400 mm x 150 mm. It was concreted a column of section 500 mm x 200 mm to 850 mm total height next to the slab. The main variables were the type of shear reinforcement "stud rails" x "double headed studs, the "studs" diameter and the shear reinforcement area per layer. The slabs were tested until the failure. It was monitored the deflection, reinforcement deformation of bending and shear. All slabs failed by punching with internal surface rupture. The experimental results after being compared with the expected standard in each individual calculation showed conservative values. Slabs of Group 1 with "stud rails" presented failed loads greater than those in Group 2 with "double headed studs. Codes/standards 318/2005 ACI, CEB-FIP MC/1990, EUROCODE 2 / 2004 and NBR 6118:2003 safely predict the failed loads of all slabs. The base of the shear reinforcement type "stud rails" moving inside the column may have reduced the failed load of the slab L3. Shear reinforcement type stud rails it is easer of assembly and play than the type double headed studs .
Compromissos em equipes de projeto de edifícios
(Universidade Federal de Goiás, 2014-08-25) Santos, Vinícius Carrião dos; Amaral, Tatiana Gondim do; http://lattes.cnpq.br/7298757233386815; Amaral, Tatiana Gondim do; Brandstetter, Maria Carolina Gomes de Oliveira; Barros Neto, José de Paula
The ineffectiveness and inefficiency of the commitments set out within the building project teams cause losses as rework, delays and additional costs for the following phases of the project and undermine interpersonal relationships. Communication is the tool used to coordinate actions to achieve the completion of the whole project. The observation of the process of establishing commitment allowed to recognize the dynamics of actions that involves the commitments and the possible impacts of the quality of these commitments in the design process. The goal of the research was to investigate how the commitments are established through conversations and interaction between participants of the project coordination team through Conversation Analysis technique. The research has a qualitative and exploratory character and was developed a case study of project coordination meetings. As results can be seen that the Conversation Analysis technique is suitable as a support for the study of commitment, was identified what actions are more closely linked to commitment and also suggested guidelines for practitioners to value the time of commitments establishment. In the academic field, the research contributes to enhancing the theme of communication and interaction in Construction, approach still recent in Brazil and worldwide. To the practice of managing the design process, the research presents a technique that can help agents to improve their communication skills and grasp its commitments as set out in the workplace by providing means to assess and adjust the process while developing.

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