In this dissertation, a research effort aimed at development and implementation of a direct field test method to evaluate the linear and nonlinear shear modulus of soil is presented. The field method utilizes a surface footing that is dynamically loaded horizontally. The test procedure involves applying static and dynamic loads to the surface footing and measuring the soil response beneath the loaded area using embedded geophones. A wide range in dynamic loads under a constant static load permits measurements of linear and nonlinear shear wave propagation from which shear moduli and associated shearing strains are evaluated. Shear wave velocities in the linear and nonlinear strain ranges are calculated from time delays in waveforms monitored by geophone pairs. Shear moduli are then obtained using the shear wave velocities and the mass density of a soil. Shear strains are determined using particle displacements calculated from particle velocities measured at the geophones by assuming a linear variation between geophone pairs. The field test method was validated by conducting an initial field experiment at sandy site in Austin, Texas. Then, field experiments were performed on cemented alluvium, a complex, hard-to-sample material. Three separate locations at Yucca Mountain, Nevada were tested. The tests successfully measured: (1) the effect of confining pressure on shear and compression moduli in the linear strain range and (2) the effect of strain on shear moduli at various states of stress in the field. The field measurements were first compared with empirical relationships for uncemented gravel. This comparison showed that the alluvium was clearly cemented. The field measurements were then compared to other independent measurements including laboratory resonant column tests and field seismic tests using the spectral-analysis-of-surface-waves method. The results from the field tests were generally in good agreement with the other independent test results, indicating that the proposed method has the ability to directly evaluate complex material like cemented alluvium in the field. / text

Federal regulation 49 CFR 193 and standard NFPA 59A require the use of validated consequence models to determine the vapor cloud dispersion exclusion zones for accidental liquefied natural gas (LNG) releases. For modeling purposes, the physical process of dispersion of LNG release can be simply divided into two stages: source term and atmospheric dispersion. The former stage occurs immediately following the release where the behavior of fluids (LNG and its vapor) is mainly controlled by release conditions. After this initial stage, the atmosphere would increasingly dominate the vapor dispersion behavior until it completely dissipates. In this work, these two stages are modeled separately by a source term model and a dispersion model due to the different parameters used to describe the physical process at each stage. The principal focus of the source term study was on LNG underwater release, since there has been far less research conducted in developing and testing models for the source of LNG release underwater compared to that for LNG release onto land or water. An underwater LNG release test was carried out to understand the phenomena that occur when LNG is released underwater and to determine the characteristics of pool formation and the vapor cloud generated by the vaporization of LNG underwater. A mathematical model was used and validated against test data to calculate the temperature of the vapor emanating from the water surface. This work used the ANSYS CFX, a general-purpose computational fluid dynamics (CFD) package, to model LNG vapor dispersion in the atmosphere. The main advantages of CFD codes are that they have the capability of defining flow physics and allowing for the representation of complex geometry and its effects on vapor dispersion. Discussed are important parameters that are essential inputs to the ANSYS CFX simulations, including the mesh size and shape, atmospheric conditions, turbulence from the source term, ground surface roughness height, and effects of obstacles. A sensitivity analysis was conducted to illustrate the impact of key parameters on the accuracy of simulation results. In addition, a series of medium-scale LNG spill tests have been performed at the Brayton Fire Training Field (BFTF), College Station, TX. The objectives of these tests were to study key parameters of modeling the physical process of LNG vapor dispersion and collect data for validating the ANSYS CFX prediction results. A comparison of test data with simulation results demonstrated that CFX described the physical behavior of LNG vapor dispersion well, and its prediction results of distances to the half lower flammable limit were in good agreement with the test data.

Title: Field tests relevancy (equipollence) of endurance predisposition of professional footballers. Made by: Bc. Martin Paroulek Supervisor: Prof. Ing. Václav Bunc, Csc. Aims: Contribute to solve problems with defining the level of endurance predisposition of professional footballers. Methods: 10 professional footballers were tested. Their average age was 19,1±0,9 years, average weight was 69,2±2,5 kg and average height was 178±4,2 cm. Data was obtained from three functional load tests. Data was processed by means of correlative analysis. Assumed level of equipollence among load tests was defined 0,7. Results: We haven't found significant relation betweeen measured figures of VO2max laboratory load test and measured figures of field 2 km run test. We even haven't found significant relation between measured figures of VO2max laboratory load test and measured figures of field endurance 20 m shuttle run test. As we can see from the results, field tests cannot be considered as adequate compensation of laboratory tests. More research is needed at this field of survey to be able to confirm it or adjust it. We are aware of limits of our survey and its value of notice, for example number of probands etc. It was confirmed that 2 km run test has higher level of equipollence (0,41) in laboratory load test...

A geração de resíduos provocada pela atividade mineradora é revestida de considerável preocupação ambiental, tanto em função da área envolvida no depósito deste material, quanto pelos impactos causados por eventuais rupturas que possam a ocorrer nestes reservatórios. O método de disposição de resíduos, frequentemente utilizado pelas mineradoras, consiste no bombeamento do material por via úmida até os reservatórios de alteamento contidos através de diques ou barragens. Este processo pode tornar estas áreas suscetíveis à ocorrência de rupturas causadas por liquefação do material. Quando este tipo de evento acontece, tem-se um aumento repentino da poropressão, com consequente redução da resistência ao cisalhamento. A verificação do potencial de liquefação de resíduos de mineração é, portanto, imprescindível à prevenção de impactos ambientais, além de colaborar na execução de projetos geotécnicos mais seguros e econômicos. Neste trabalho são analisados três reservatórios distintos, sendo um composto por resíduo de mineração de ouro e os outros dois por resíduo de mineração de bauxita. Os resultados de ensaios realizados em campo (SCPTU/CPTU e SDMT) são utilizados na avaliação geotécnica dos resíduos, buscando-se verificar a compatibilidade com avaliações já realizadas através de ensaios de laboratório. O potencial de liquefação estática dos materiais é observado em laboratório para baixos níveis de tensões, demonstrando que os resíduos são suscetíveis à liquefação estática. Este comportamento é verificado também na interpretação de ensaios de campo, interpretados através de correlações de natureza semiempírica baseadas na combinação de uma medida representativa de pequenas deformações (módulo cisalhante) combinado a uma medida obtida à grandes deformações (resistência à penetração) que, combinadas, permitem a determinação do parâmetro de estado do material. A primeira proposta consistiu na definição de uma fronteira entre materiais de comportamento contrátil e dilatante no espaço G0/qc versus p’/pa. Esta proposta apresentou uma resposta adequada, entretanto, a concentração de todos os pontos referentes aos resíduos analisados, possivelmente suscetíveis ao fenômeno de liquefação estática, numa mesma região gráfica, somente foi possível no espaço G0/qc versus qc1. Neste espaço a separação entre materiais de comportamento dilatante e contrátil foi possível com a inserção de uma fronteira empírica. Este estudo demonstrou a boa sensibilidade dos parâmetros G0 e qc ao fenômeno de liquefação estática. A suscetibilidade à liquefação cíclica dos resíduos de mineração de ouro e bauxita também foi verificada através de correlações com resultados de ensaios de campo. Esta análise indicou a possibilidade de ocorrência do fenômeno para os mais baixos níveis de magnitude de sismo atuante. / Waste generation caused by mining activity emerges as an environmental concern, both because of the large area involved in deposits of this material, as well as the possible impacts caused by occasional failures that may occur in these deposits. The method of waste disposal, often used by mining companies, consists by pumping wet material in sequence until completion of the reservoirs contained by dikes or dams. This process makes these areas susceptible to the occurrence of the liquefaction failures. When this type of event happens there is a sudden increase in pore pressure with consequent reduction shear strength, which can result is risk of containment structures. Therefore, verification of liquefaction potential of these materials is essential in the prevention of environmental impacts. The present work analyzes three different reservoirs, one consisting of gold mining tailings and the other two of bauxite mining tailings. The results of field tests (SCPTU/ CPTU and SDMT) are used in geotechnical evaluation of tailings in order to verify the compatibility with evaluations already carried out through laboratory tests. The static liquefaction potential observed in laboratory at low levels of stresses is consistent with field assessment from in situ tests. Semiempirical correlations based on field tests are based on small strain measurements (shear modulus) combined with large strain measurements (penetration resistance), that are used to defined the state parameter of the material. The first proposal consisted in defining a boundary between materials of contractive and dilatant behavior in space G0/qc versus p’/pa. The proposal presented an appropriate response, however, the concentration of all analyzed points, possibly susceptible to static liquefaction phenomenon, in the same graphical region was only possible in space G0/qc versus qc1. In this space the separation between materials of contractive and dilatant behavior was possible with the inclusion of an empirical boundary. This study demonstrated the good sensitivity of the parameters G0 and qc to the static liquefaction phenomenon. The cyclic liquefaction susceptibility of the gold and bauxite mining tailings was also verified by correlation with field tests results. This analyzes indicated the possibility of occurrence of the phenomenon to the lowest levels of earthquake magnitude.

Vibration-based damage identification (VBDI) techniques have been developed in part to address the problems associated with an aging civil infrastructure. To assess the potential of VBDI as it applies to highway bridges in Iowa, three applications of VBDI techniques were considered in this study: numerical simulation, laboratory structures, and field structures. VBDI techniques were found to be highly capable of locating and quantifying damage in numerical simulations. These same techniques were found to be accurate in locating various types of damage in a laboratory setting with actual structures. Although there is the potential for these techniques to quantify damage in a laboratory setting, the ability of the methods to quantify low-level damage in the laboratory is not robust. When applying these techniques to an actual bridge, it was found that some traditional applications of VBDI methods are capable of describing the global behavior of the structure but are most likely not suited for the identification of typical damage scenarios found in civil infrastructure. Measurement noise, boundary conditions, complications due to substructures and multiple material types, and transducer sensitivity make it very difficult for present VBDI techniques to identify, much less quantify, highly localized damage (such as small cracks and minor changes in thickness). However, while investigating VBDI techniques in the field, a novel methodology, operational response and waveform analysis (ORWA), was developed to extend the focus of traditional VBDI techniques by correlating bridge damage to operational structural motion. It was found that if the frequency-domain response of the structure can be generated from operating traffic load, the structural response can be animated and used to develop a holistic view of the bridge's response to various automobile loadings. By animating the response of a field bridge, concrete cracking (in the abutment and deck) was correlated with structural motion and problem frequencies (i.e., those that cause significant torsion or tension-compression at beam ends) were identified. Furthermore, a frequency-domain study of operational traffic was used to identify both common and extreme frequencies for a given structure and loading. Finally, a finite element analysis of a structure similar to the field bridge was carried out to supplement and partially verify experimental results. Further work should (1) perfect the process of collecting high-quality operational frequency response data; (2) expand and simplify the process of correlating frequency response animations with damage; and (3) develop efficient, economical, pre-emptive solutions to common damage types identified by ORWA.

O rugby union XV é um esporte coletivo e de invasão praticado em um campo gramado por duas equipes compostas por 15 jogadores cada e divididos em dois grupos denominados forwards (8 jogadores) e backs (7 jogadores) de acordo com a função desempenhada durante a partida. As demandas física e fisiológica do rugby exigem que os atletas recuperem suas reservas energéticas em pequenos intervalos ou durante exercícios de baixa intensidade. Desta forma, o consumo máximo de oxigênio (VO2Máx), indicador de potência aeróbia, torna-se uma variável importante para o desempenho na modalidade. O objetivo deste estudo foi verificar a possibilidade de predizer a potência aeróbia em jogadores amadores de rugby union XV utilizando os testes de campo Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IRT1) e 5 m Multiple Shuttle Test (5-m MST). Para isso, 42 jogadores, 22 forwards e 20 backs, foram avaliados em três etapas: (1) em laboratório com teste máximo em esteira; (2) teste de campo definido por sorteio na primeira etapa; e (3) segundo teste de campo. Com os dados obtidos nos três testes foram realizadas análises descritivas, de comparação, de correlação, de regressão e de concordância. Dentre os principais resultados, backs, em comparação a forwards, apresentaram maior VO2Máx (respectivamente, 61,7 ± 15 ml.kg-1.min-1 e 51,6 ± 10,1 ml.kg-1.min-1), resultado no Yo- Yo IRT1 (respectivamente, 16,4 ± 0,8 e 14,9 ± 0,9) e distância final no Yo-Yo IRT1 (respectivamente, 1283,3± 312,5 m e 792 ± 277,6 m). Foram encontradas correlações significativas entre resultado final e distância final total obtidas no Yo-Yo IRT1 e o VO2Máx relativo a massa corporal (respectivamente, r = 0,425 e r = 0,459). Utilizandose a distância final percorrida no Yo-Yo IRT1, o VO2Máx, em jogadores de rugby, pode ser estimado com a aplicação da equação VO2Máx = 0,016(DIST Yo-Yo) + 40,578. / Rugby Union XV is a sport played in pitches by two teams of 15 players each. The players are divided into two groups according to the role in the game: the forwards (8 players) and the backs (7 players). During a match, the physical and physiological demands of rugby require that athletes recover its energy reserves in shorts intervals or during low-intensity exercise. Thus, the maximal oxygen uptake (VO2Max), an aerobic power index, becomes an important variable for the performance in the discipline. The objective of this study was to verify the possibility to predict the aerobic power in rugby union XV amateur players using the field tests Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IRT1) and 5 m Multiple Shuttle Test (5-m MST). Forty-two players, 22 forwards and 20 backs, were evaluated in three phases: (1) in a laboratory with maximum treadmill test; (2) field test set by a draw in the first phase; and (3) second field test. Descriptive, comparison, correlation, regression and level of agreement analyses were performed. Among the mayor results, backs, compared with forwards, reported a higher VO2Max (respectively 61.7 ± 15 ml.kg-1.min-1 and 51.6 ± 10.1 ml.kg- 1.min-1), Yo-Yo IRT1 results (respectively 16.4 ± 0.8 and 14.9 ± 0.9), and Yo-Yo IRT1 total distance (respectively 1283.3± 312.5 m e 792 ± 277.6 m). Significant correlations were found between the result and total distance on the Yo-Yo IRT1 and the VO2Max (respectively r = 0.425 and r = 0.459). Using the total distance covered on the Yo-Yo IRT1, the VO2Max in rugby players, can be estimated using the equation VO2Max = 0.016(DIST Yo-Yo) + 40.578.

O rugby union XV é um esporte coletivo e de invasão praticado em um campo gramado por duas equipes compostas por 15 jogadores cada e divididos em dois grupos denominados forwards (8 jogadores) e backs (7 jogadores) de acordo com a função desempenhada durante a partida. As demandas física e fisiológica do rugby exigem que os atletas recuperem suas reservas energéticas em pequenos intervalos ou durante exercícios de baixa intensidade. Desta forma, o consumo máximo de oxigênio (VO2Máx), indicador de potência aeróbia, torna-se uma variável importante para o desempenho na modalidade. O objetivo deste estudo foi verificar a possibilidade de predizer a potência aeróbia em jogadores amadores de rugby union XV utilizando os testes de campo Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IRT1) e 5 m Multiple Shuttle Test (5-m MST). Para isso, 42 jogadores, 22 forwards e 20 backs, foram avaliados em três etapas: (1) em laboratório com teste máximo em esteira; (2) teste de campo definido por sorteio na primeira etapa; e (3) segundo teste de campo. Com os dados obtidos nos três testes foram realizadas análises descritivas, de comparação, de correlação, de regressão e de concordância. Dentre os principais resultados, backs, em comparação a forwards, apresentaram maior VO2Máx (respectivamente, 61,7 ± 15 ml.kg-1.min-1 e 51,6 ± 10,1 ml.kg-1.min-1), resultado no Yo- Yo IRT1 (respectivamente, 16,4 ± 0,8 e 14,9 ± 0,9) e distância final no Yo-Yo IRT1 (respectivamente, 1283,3± 312,5 m e 792 ± 277,6 m). Foram encontradas correlações significativas entre resultado final e distância final total obtidas no Yo-Yo IRT1 e o VO2Máx relativo a massa corporal (respectivamente, r = 0,425 e r = 0,459). Utilizandose a distância final percorrida no Yo-Yo IRT1, o VO2Máx, em jogadores de rugby, pode ser estimado com a aplicação da equação VO2Máx = 0,016(DIST Yo-Yo) + 40,578. / Rugby Union XV is a sport played in pitches by two teams of 15 players each. The players are divided into two groups according to the role in the game: the forwards (8 players) and the backs (7 players). During a match, the physical and physiological demands of rugby require that athletes recover its energy reserves in shorts intervals or during low-intensity exercise. Thus, the maximal oxygen uptake (VO2Max), an aerobic power index, becomes an important variable for the performance in the discipline. The objective of this study was to verify the possibility to predict the aerobic power in rugby union XV amateur players using the field tests Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IRT1) and 5 m Multiple Shuttle Test (5-m MST). Forty-two players, 22 forwards and 20 backs, were evaluated in three phases: (1) in a laboratory with maximum treadmill test; (2) field test set by a draw in the first phase; and (3) second field test. Descriptive, comparison, correlation, regression and level of agreement analyses were performed. Among the mayor results, backs, compared with forwards, reported a higher VO2Max (respectively 61.7 ± 15 ml.kg-1.min-1 and 51.6 ± 10.1 ml.kg- 1.min-1), Yo-Yo IRT1 results (respectively 16.4 ± 0.8 and 14.9 ± 0.9), and Yo-Yo IRT1 total distance (respectively 1283.3± 312.5 m e 792 ± 277.6 m). Significant correlations were found between the result and total distance on the Yo-Yo IRT1 and the VO2Max (respectively r = 0.425 and r = 0.459). Using the total distance covered on the Yo-Yo IRT1, the VO2Max in rugby players, can be estimated using the equation VO2Max = 0.016(DIST Yo-Yo) + 40.578.

Made available in DSpace on 2014-10-09T12:47:17Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:54Z (GMT). No. of bitstreams: 1 07965.pdf: 13989863 bytes, checksum: 2913793c77d98e847907fe76fc84fe02 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

A geração de resíduos provocada pela atividade mineradora é revestida de considerável preocupação ambiental, tanto em função da área envolvida no depósito deste material, quanto pelos impactos causados por eventuais rupturas que possam a ocorrer nestes reservatórios. O método de disposição de resíduos, frequentemente utilizado pelas mineradoras, consiste no bombeamento do material por via úmida até os reservatórios de alteamento contidos através de diques ou barragens. Este processo pode tornar estas áreas suscetíveis à ocorrência de rupturas causadas por liquefação do material. Quando este tipo de evento acontece, tem-se um aumento repentino da poropressão, com consequente redução da resistência ao cisalhamento. A verificação do potencial de liquefação de resíduos de mineração é, portanto, imprescindível à prevenção de impactos ambientais, além de colaborar na execução de projetos geotécnicos mais seguros e econômicos. Neste trabalho são analisados três reservatórios distintos, sendo um composto por resíduo de mineração de ouro e os outros dois por resíduo de mineração de bauxita. Os resultados de ensaios realizados em campo (SCPTU/CPTU e SDMT) são utilizados na avaliação geotécnica dos resíduos, buscando-se verificar a compatibilidade com avaliações já realizadas através de ensaios de laboratório. O potencial de liquefação estática dos materiais é observado em laboratório para baixos níveis de tensões, demonstrando que os resíduos são suscetíveis à liquefação estática. Este comportamento é verificado também na interpretação de ensaios de campo, interpretados através de correlações de natureza semiempírica baseadas na combinação de uma medida representativa de pequenas deformações (módulo cisalhante) combinado a uma medida obtida à grandes deformações (resistência à penetração) que, combinadas, permitem a determinação do parâmetro de estado do material. A primeira proposta consistiu na definição de uma fronteira entre materiais de comportamento contrátil e dilatante no espaço G0/qc versus p’/pa. Esta proposta apresentou uma resposta adequada, entretanto, a concentração de todos os pontos referentes aos resíduos analisados, possivelmente suscetíveis ao fenômeno de liquefação estática, numa mesma região gráfica, somente foi possível no espaço G0/qc versus qc1. Neste espaço a separação entre materiais de comportamento dilatante e contrátil foi possível com a inserção de uma fronteira empírica. Este estudo demonstrou a boa sensibilidade dos parâmetros G0 e qc ao fenômeno de liquefação estática. A suscetibilidade à liquefação cíclica dos resíduos de mineração de ouro e bauxita também foi verificada através de correlações com resultados de ensaios de campo. Esta análise indicou a possibilidade de ocorrência do fenômeno para os mais baixos níveis de magnitude de sismo atuante. / Waste generation caused by mining activity emerges as an environmental concern, both because of the large area involved in deposits of this material, as well as the possible impacts caused by occasional failures that may occur in these deposits. The method of waste disposal, often used by mining companies, consists by pumping wet material in sequence until completion of the reservoirs contained by dikes or dams. This process makes these areas susceptible to the occurrence of the liquefaction failures. When this type of event happens there is a sudden increase in pore pressure with consequent reduction shear strength, which can result is risk of containment structures. Therefore, verification of liquefaction potential of these materials is essential in the prevention of environmental impacts. The present work analyzes three different reservoirs, one consisting of gold mining tailings and the other two of bauxite mining tailings. The results of field tests (SCPTU/ CPTU and SDMT) are used in geotechnical evaluation of tailings in order to verify the compatibility with evaluations already carried out through laboratory tests. The static liquefaction potential observed in laboratory at low levels of stresses is consistent with field assessment from in situ tests. Semiempirical correlations based on field tests are based on small strain measurements (shear modulus) combined with large strain measurements (penetration resistance), that are used to defined the state parameter of the material. The first proposal consisted in defining a boundary between materials of contractive and dilatant behavior in space G0/qc versus p’/pa. The proposal presented an appropriate response, however, the concentration of all analyzed points, possibly susceptible to static liquefaction phenomenon, in the same graphical region was only possible in space G0/qc versus qc1. In this space the separation between materials of contractive and dilatant behavior was possible with the inclusion of an empirical boundary. This study demonstrated the good sensitivity of the parameters G0 and qc to the static liquefaction phenomenon. The cyclic liquefaction susceptibility of the gold and bauxite mining tailings was also verified by correlation with field tests results. This analyzes indicated the possibility of occurrence of the phenomenon to the lowest levels of earthquake magnitude.

O rugby union XV é um esporte coletivo e de invasão praticado em um campo gramado por duas equipes compostas por 15 jogadores cada e divididos em dois grupos denominados forwards (8 jogadores) e backs (7 jogadores) de acordo com a função desempenhada durante a partida. As demandas física e fisiológica do rugby exigem que os atletas recuperem suas reservas energéticas em pequenos intervalos ou durante exercícios de baixa intensidade. Desta forma, o consumo máximo de oxigênio (VO2Máx), indicador de potência aeróbia, torna-se uma variável importante para o desempenho na modalidade. O objetivo deste estudo foi verificar a possibilidade de predizer a potência aeróbia em jogadores amadores de rugby union XV utilizando os testes de campo Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IRT1) e 5 m Multiple Shuttle Test (5-m MST). Para isso, 42 jogadores, 22 forwards e 20 backs, foram avaliados em três etapas: (1) em laboratório com teste máximo em esteira; (2) teste de campo definido por sorteio na primeira etapa; e (3) segundo teste de campo. Com os dados obtidos nos três testes foram realizadas análises descritivas, de comparação, de correlação, de regressão e de concordância. Dentre os principais resultados, backs, em comparação a forwards, apresentaram maior VO2Máx (respectivamente, 61,7 ± 15 ml.kg-1.min-1 e 51,6 ± 10,1 ml.kg-1.min-1), resultado no Yo- Yo IRT1 (respectivamente, 16,4 ± 0,8 e 14,9 ± 0,9) e distância final no Yo-Yo IRT1 (respectivamente, 1283,3± 312,5 m e 792 ± 277,6 m). Foram encontradas correlações significativas entre resultado final e distância final total obtidas no Yo-Yo IRT1 e o VO2Máx relativo a massa corporal (respectivamente, r = 0,425 e r = 0,459). Utilizandose a distância final percorrida no Yo-Yo IRT1, o VO2Máx, em jogadores de rugby, pode ser estimado com a aplicação da equação VO2Máx = 0,016(DIST Yo-Yo) + 40,578. / Rugby Union XV is a sport played in pitches by two teams of 15 players each. The players are divided into two groups according to the role in the game: the forwards (8 players) and the backs (7 players). During a match, the physical and physiological demands of rugby require that athletes recover its energy reserves in shorts intervals or during low-intensity exercise. Thus, the maximal oxygen uptake (VO2Max), an aerobic power index, becomes an important variable for the performance in the discipline. The objective of this study was to verify the possibility to predict the aerobic power in rugby union XV amateur players using the field tests Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IRT1) and 5 m Multiple Shuttle Test (5-m MST). Forty-two players, 22 forwards and 20 backs, were evaluated in three phases: (1) in a laboratory with maximum treadmill test; (2) field test set by a draw in the first phase; and (3) second field test. Descriptive, comparison, correlation, regression and level of agreement analyses were performed. Among the mayor results, backs, compared with forwards, reported a higher VO2Max (respectively 61.7 ± 15 ml.kg-1.min-1 and 51.6 ± 10.1 ml.kg- 1.min-1), Yo-Yo IRT1 results (respectively 16.4 ± 0.8 and 14.9 ± 0.9), and Yo-Yo IRT1 total distance (respectively 1283.3± 312.5 m e 792 ± 277.6 m). Significant correlations were found between the result and total distance on the Yo-Yo IRT1 and the VO2Max (respectively r = 0.425 and r = 0.459). Using the total distance covered on the Yo-Yo IRT1, the VO2Max in rugby players, can be estimated using the equation VO2Max = 0.016(DIST Yo-Yo) + 40.578.