No / Axially loaded rubber blocks of long, thin rectangular and circular cross section whose ends are bonded to rigid plates are studied. Closed-form expressions, which satisfy exactly the governing equations and conditions based upon the classical theory of elasticity, are derived for the total axial deflection and stress distribution using a superposition approach. The corresponding relations are presented for readily calculating the apparent Young's modulus, Ea, the modified modulus, E'a, and the deformed lateral profiles of the blocks. From these, improved approximate elementary expressions for evaluating Ea and E'a are deduced. These estimates, and the precisely found values, agree for large values of the shape factor S, with those previously suggested, but also fit the experimental data more closely for small values of S. Confirmation is provided that the assumption of a parabolic lateral profile is invalid for small values of S.

Les structures offshores sont conçues pour résister à des chargements environnementaux sévères. Des études expérimentales et numériques de la fondation d’une éolienne offshore soumise à des chargements statiques monotones/cycliques sont présentées dans ce manuscrit. Des pieux isolés (diamètre de 1,8 m et 40 m de longueur) et une structure en treillis fondée sur 4 pieux ont été testés à 100×g en centrifuge dans un massif de sable de Fontainebleau dense. Le comportement du pieu isolé a été identifié à travers des essais de chargement axial monotone. Différentes méthodes de mise en place de pieu ont été adoptées (installation à 1×g et à 100×g) et leur influence sur la capacité portante a été mesurée. Le diagramme de stabilité du pieu a été construit à partir des résultats des essais cycliques, des essais CPT ont été réalisés et l’influence des contraintes initiales a été étudiée. Des résultats expérimentaux de la fondation jacket soumise à des chargements latéraux cycliques sont enfin présentés. La méthode des éléments finis et un macro-élément pour des pieux ont été utilisés pour reproduire numériquement les résultats expérimentaux. Les lois de comportement adoptées sont basées sur la théorie d’hypo-plasticité et les contraintes initiales dans le sol sont issues de la méthode ICP-05. Les résultats numériques sont confrontés aux résultats expérimentaux et aux résultats analytiques obtenus à partir de la norme API. / Offshore structures are designed to resist to severe environmental loads. This manuscript presents experimental and numerical studies on offshore wind turbine pile foundations submitted to static monotonic/cyclic loads. Isolated piles (diameter of 1.8 m and embedded length of 40m) and a four-legged truss structure installed in dense Fontainebleau sand have been tested at 100×g in a geotechnical centrifuge. The behavior of the isolated piles has been characterized under monotonic axial load. The piles have been jacketed at 1×g and 100×g and the influence of the setup method on the bearing capacity has been measured. The stability diagram of a pile has been constructed using cyclic tests, CPT experiments have been performed and the influence of the initial stresses has been studied. Finally, experimental results of the jacket foundation submitted to lateral cyclic loadings are presented. The finite element method and a macro-element for piles have been used to numerically reproduce the experimental results. Constitutive laws are based on the hypoplasticity theory and the initial stresses in the soil have been calculated using the IC-05 method. The numerical results are compared with the experimental and the analytical results from the API standards.

O objetivo desta pesquisa foi avaliar e comparar a atividade eletromiográfica de sete músculos da cintura escapular e braço durante a realização dos exercícios wall-press, bench-press e push-up sobre uma superfície estável e com carga axial controlada em dois níveis de esforço isométrico, um máximo (100%) e outro submáximo (80%). Os exercícios foram realizados com o braço em 90° de flexão no plano sagital, 0° de extensão do cotovelo e 90° de flexão da mão. Vinte voluntários do sexo masculino, saudáveis, destros e sem história de trauma no membro superior participaram da pesquisa. Os registros eletromiográficos e de força foram adquiridos, respectivamente, por sete canais para eletromiograma e por um canal auxiliar de um sistema de aquisição simultânea, ganho total de 50 vezes, 12 bits de faixa de resolução dinâmica e freqüência de amostragem por canal de 4 KHZ. Os sinais mioelétricos foram captados por eletrodos ativos simples diferencial, ganho de 20 vezes, impedância de entrada de 10G? e CMRR mínimo de 130 dB, colocados nos músculos serrátil anterior, porção anterior e posterior do músculo deltóide, porção clavicular do peitoral maior, fibras superiores do trapézio, cabeça longa do bíceps e tríceps braquial. Os exercícios foram realizados aleatoriamente, nos dois níveis de esforço isométrico, com intervalados entre si por 5 minutos. Os voluntários realizaram três repetições de cada exercício, com duração de 6 segundos cada, intervaladas entre si por 1,5 minutos e manutenção da força dentro dos valores previamente definidos, orientadas por um feedback sonoro. Os sinais brutos foram filtrados por um passa faixa de 20-500Hz, derivando os valores de amplitude eletromiográfica pelo cálculo da Root Mean Square (RMS). Os valores de RMS foram normalizados pelo valor máximo obtido de três contrações isométricas voluntárias máximas obtidas em prova de função muscular. A comparação dos valores normalizados entre os três exercícios nos dois níveis de esforço isométrico e entre o mesmo exercício nos dois níveis de esforço isométrico foi realizada através do Modelo Linear de Efeitos Mistos, com nível de significância de 5%. Os valores normalizados de RMS dos músculos estudados, em valores percentuais, foram usados para graduar o nível de atividade elétrica obtido em cada exercício. Os resultados demonstraram que houve uma diferença nos valores de RMS normalizados dos músculos avaliados nas comparações feitas entre os três exercícios, não confirmando a hipótese inicial deste trabalho, pois os dois níveis de esforços isométricos não foram capazes de influenciar a resposta eletromiográfica. Diferenças entre amplitudes de ativação normalizadas foram constatadas, variando entre os níveis mínimo e alto. O bench-press gerou maiores níveis de atividade eletromiográfica para a maioria dos músculos, possivelmente pelo maior esforço isométrico realizado. O wall-press gerou maior atividade eletromiográfica para a maioria dos músculos quando comparado ao push-up, apesar do esforço isométrico gerado ser menor. Este trabalho concluiu que, apesar de exercícios com carga axial, mesmo com esforço isométrico controlado, causaram diferentes níveis de atividade eletromiográfica nos músculos avaliados. / The purpose of this research was to investigate if biomechanically similar exercises produce similar myoelectric activation when the same level of maximal isometric effort is produced. Twenty volunteers participated in the study. All volunteers were right-handed, healthy men with no history of previous upper limb trauma. Electromyographic (EMG) recordings were obtained using a seven-channel simultaneous acquisition system, with gain of 50, 12 bit A/D converter board with a 4 KHz frequency. To monitor produced force, a load cell was attached through an auxiliary channel and force recording was accomplished simultaneously with the acquisition of EMG signal. Myoelectric signals were obtained using simple differential electrodes, with gain of 20, input impedance of 10 G? and minimum CMRR of 130 dB, placed on the serratus anterior, posterior and anterior deltoid, clavicular portion of the pectoralis major, upper trapezius, and biceps and triceps brachii muscles, following the European Recommendations for Surface Electromyography by SENIAM project, and instructions by Hintermeinster et al. (1998). EMG signals were recorded while performing push-up, bench-press, and wall-press exercises at different force levels (100% and 80% maximum isometric effort) with the dominant upper limb supported on a stable surface. Exercises were randomly performed with five-minute intervals between each exercise. Volunteers performed three repetitions of each exercise, each lasting six seconds, with 1.5-minute intervals, and maintaining the force within previously determined values, guided by audio feedback. Raw EMG signals were filtered by a 20-500 Hz pass-band in order to derivate EMG amplitude values by intervals calculating the Root Mean Square (RMS). RMS values were normalized by the maximum value obtained in three maximal voluntary isometric contractions during muscle testing. Normalized values were compared between the three exercises at both torque levels and between the same exercise at both isometric effort levels through the mixed-effects linear model, with a 5% level of significance. Normalized RMS values of the studied muscles (%) were used to rank the level of electric activity obtained during each exercise. Results indicate that maximal isometric effort levels had no influence on results from the comparison of EMG activity in any of the proposed exercises. Differences between normalized activation amplitudes were observed. However, the values reached levels between minimal and high, that is, under 60% of the activity generated during maximal voluntary isometric contraction. This study concludes that biomechanically comparable exercises did not necessarily produce similar EMG activity, in spite of controlling isometric effort. Moreover, exercises were capable of generating different EMG activity levels in the evaluated muscles. Therefore, such exercises are indicated for different rehabilitation program phases.

O objetivo desta pesquisa foi avaliar e comparar a atividade eletromiográfica de sete músculos da cintura escapular e braço durante a realização dos exercícios wall-press, bench-press e push-up sobre uma superfície estável e com carga axial controlada em dois níveis de esforço isométrico, um máximo (100%) e outro submáximo (80%). Os exercícios foram realizados com o braço em 90° de flexão no plano sagital, 0° de extensão do cotovelo e 90° de flexão da mão. Vinte voluntários do sexo masculino, saudáveis, destros e sem história de trauma no membro superior participaram da pesquisa. Os registros eletromiográficos e de força foram adquiridos, respectivamente, por sete canais para eletromiograma e por um canal auxiliar de um sistema de aquisição simultânea, ganho total de 50 vezes, 12 bits de faixa de resolução dinâmica e freqüência de amostragem por canal de 4 KHZ. Os sinais mioelétricos foram captados por eletrodos ativos simples diferencial, ganho de 20 vezes, impedância de entrada de 10G? e CMRR mínimo de 130 dB, colocados nos músculos serrátil anterior, porção anterior e posterior do músculo deltóide, porção clavicular do peitoral maior, fibras superiores do trapézio, cabeça longa do bíceps e tríceps braquial. Os exercícios foram realizados aleatoriamente, nos dois níveis de esforço isométrico, com intervalados entre si por 5 minutos. Os voluntários realizaram três repetições de cada exercício, com duração de 6 segundos cada, intervaladas entre si por 1,5 minutos e manutenção da força dentro dos valores previamente definidos, orientadas por um feedback sonoro. Os sinais brutos foram filtrados por um passa faixa de 20-500Hz, derivando os valores de amplitude eletromiográfica pelo cálculo da Root Mean Square (RMS). Os valores de RMS foram normalizados pelo valor máximo obtido de três contrações isométricas voluntárias máximas obtidas em prova de função muscular. A comparação dos valores normalizados entre os três exercícios nos dois níveis de esforço isométrico e entre o mesmo exercício nos dois níveis de esforço isométrico foi realizada através do Modelo Linear de Efeitos Mistos, com nível de significância de 5%. Os valores normalizados de RMS dos músculos estudados, em valores percentuais, foram usados para graduar o nível de atividade elétrica obtido em cada exercício. Os resultados demonstraram que houve uma diferença nos valores de RMS normalizados dos músculos avaliados nas comparações feitas entre os três exercícios, não confirmando a hipótese inicial deste trabalho, pois os dois níveis de esforços isométricos não foram capazes de influenciar a resposta eletromiográfica. Diferenças entre amplitudes de ativação normalizadas foram constatadas, variando entre os níveis mínimo e alto. O bench-press gerou maiores níveis de atividade eletromiográfica para a maioria dos músculos, possivelmente pelo maior esforço isométrico realizado. O wall-press gerou maior atividade eletromiográfica para a maioria dos músculos quando comparado ao push-up, apesar do esforço isométrico gerado ser menor. Este trabalho concluiu que, apesar de exercícios com carga axial, mesmo com esforço isométrico controlado, causaram diferentes níveis de atividade eletromiográfica nos músculos avaliados. / The purpose of this research was to investigate if biomechanically similar exercises produce similar myoelectric activation when the same level of maximal isometric effort is produced. Twenty volunteers participated in the study. All volunteers were right-handed, healthy men with no history of previous upper limb trauma. Electromyographic (EMG) recordings were obtained using a seven-channel simultaneous acquisition system, with gain of 50, 12 bit A/D converter board with a 4 KHz frequency. To monitor produced force, a load cell was attached through an auxiliary channel and force recording was accomplished simultaneously with the acquisition of EMG signal. Myoelectric signals were obtained using simple differential electrodes, with gain of 20, input impedance of 10 G? and minimum CMRR of 130 dB, placed on the serratus anterior, posterior and anterior deltoid, clavicular portion of the pectoralis major, upper trapezius, and biceps and triceps brachii muscles, following the European Recommendations for Surface Electromyography by SENIAM project, and instructions by Hintermeinster et al. (1998). EMG signals were recorded while performing push-up, bench-press, and wall-press exercises at different force levels (100% and 80% maximum isometric effort) with the dominant upper limb supported on a stable surface. Exercises were randomly performed with five-minute intervals between each exercise. Volunteers performed three repetitions of each exercise, each lasting six seconds, with 1.5-minute intervals, and maintaining the force within previously determined values, guided by audio feedback. Raw EMG signals were filtered by a 20-500 Hz pass-band in order to derivate EMG amplitude values by intervals calculating the Root Mean Square (RMS). RMS values were normalized by the maximum value obtained in three maximal voluntary isometric contractions during muscle testing. Normalized values were compared between the three exercises at both torque levels and between the same exercise at both isometric effort levels through the mixed-effects linear model, with a 5% level of significance. Normalized RMS values of the studied muscles (%) were used to rank the level of electric activity obtained during each exercise. Results indicate that maximal isometric effort levels had no influence on results from the comparison of EMG activity in any of the proposed exercises. Differences between normalized activation amplitudes were observed. However, the values reached levels between minimal and high, that is, under 60% of the activity generated during maximal voluntary isometric contraction. This study concludes that biomechanically comparable exercises did not necessarily produce similar EMG activity, in spite of controlling isometric effort. Moreover, exercises were capable of generating different EMG activity levels in the evaluated muscles. Therefore, such exercises are indicated for different rehabilitation program phases.

The use of fully grouted reinforced masonry shear walls (RMSWs) has been growing in several areas around the world owing to their relative ease of construction and their in-plane ductile behavior. However, RMSWs possess low out-of-plane ductility which amplifies the vulnerability of such components under blast loading. Furthermore, the long time and high costs of recovery following devastating (deliberate or accidental) explosions have created a need for resilience-based design for risk mitigation, especially considering the different sources of associated uncertainty. As such, this study aims to lay out the foundations of a probabilistic resilience–based blast analysis and design framework. The framework should have the capability of quantifying the overall building post-blast functionality in order to estimate its recovery cost and time, and thus the building resilience following such a demand. The proposed framework will be specifically applied for RMSW buildings incurring blast loads through a profound investigation for the behavior of rectangular RMSWs as being a primary structural element in reinforced masonry buildings. The investigation will subsume an experimental and analytical evaluation for the performance of load-bearing RMSWs with different in-plane ductility levels subjected to out-of-plane quasi-static loading. This will be followed by a numerical investigation of RMSWs to conclude the blast probabilistic performance of RMSWs that can be applied within the proposed probabilistic resilience-based blast framework. The work in this dissertation presents a key step towards adopting resilience based analysis and design in future editions of blast-resistant construction standards and provides the decisionmakers with a complete insight into post-blast building functionality and its recovery. / Thesis / Doctor of Philosophy (PhD)

The response of wide flange steel columns subjected to constant axial loads and lateral blast loads was examined. The finite element program ABAQUS was used to model W8x40 sections with different slendernesses and boundary conditions. For the response calculations, a constant axial force was first applied to the column and the equilibrium state was determined. Next, a short duration, lateral blast load was applied and the response time history was calculated. Changes in displacement time histories and plastic hinge formations resulting from varying the axial load were examined. The cases studied include single-span and two-span columns. In addition to ideal boundary conditions, columns with linear elastic, rotational supports were also studied. Non-uniform blast loads were considered. Major axis, minor axis, and biaxial bending were investigated. The effects of strain rate and residual stresses were examined. The results for each column configuration are presented as a set of curves showing the critical blast impulse versus axial load. The critical blast impulse is defined as the impulse that either causes the column to collapse or to exceed the limiting deflection criterion. A major goal of this effort was to develop simplified design and analysis methods. To accomplish this, two single-degree-of-freedom approaches that include the effects of the axial load were derived. The first uses a bilinear resistance function that is similar to the one used for beam analysis. This approach provides a rough estimate of the critical impulse and is suitable only for preliminary design or quick vulnerability calculations. The second approach uses a nonlinear resistance function that accounts for the gradual yielding that occurs during the dynamic response. This approach can be easily implemented in a simple computer program or spreadsheet and provides close agreement with the results from the finite element method. / Ph. D.

The advancement in manufacturing technologies to produce high-performing engineered wood products (EWP) has allowed wood to be utilized beyond the traditional low-rise light-frame structures and to become a viable material option for much larger structures. Although glued-laminated timber (glulam) is included as a material option in the current blast code (CSA, 2012), its response to blast loading is not yet well documented. An experimental program investigating the behaviour of seventy glulam beams and columns was developed with focus on establishing the dynamic characteristics of glulam beams and columns with and without the effect of FRP reinforcement. A shock tube capable of simulating high strain rates similar to those experienced during blast was used. Thirty-eight beams with three different cross-sections were tested statically and dynamically to establish the high strain rate effects (dynamic increase factor). Six columns were also tested dynamically with axial load levels ranging from 15 to 75 % of the columns’ compression design capacity. Different retrofit configurations varying from simple tension reinforcement to U-shaped tension reinforcement with confinement using both unidirectional and bi-directional FRP were investigated on a total of twenty-six beams. A procedure capturing the strain-rate effects, variable axial load and FRP, was developed and found to be capable of predicting the flexural behaviour of the beams up to maximum resistance with reasonable accuracy when compared to experimentally obtained static and dynamic resistance curves. Implications on the design of both retrofitted and unretrofitted specimens are also discussed.

The aim of this Master’s thesis is to design a steam condensing turbine with three bleeds. First, a heat balance of the steam cycle is calculated, followed by thermodynamic and stress calculation of the turbine blading and design of a gland steam system and drain system. A price proposal is suggested for the given steam turbine. In the end, a design drawing of the steam turbine is constructed.

No description available.

The doctoral thesis deal with the interaction between the foundation plate and deep foundation in the form of bored piles in the case of skeleton construction. The issue of tension redistribution from the column between the plate and the pile is investigated on specific object – „Shopping and entertainment center Fórum Nová Karolina”. On this object were selected columns monitored and load tests of the piles was executed. Values of the axial loading of the piles and the actual deformation of the construction have been derived from measurements and tests. They were compared with the results of structural behavior by numerical modeling.