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To, Albert C. (Albert Chi Fu) 1975. "Lateral load capacity of drilled shafts in jointed rock." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/40018.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1999.Includes bibliographical references (p. 263).
Large vertical (axial) and lateral loads often act on the heads of drilled shafts in jointed rock. In current design practice, the p-y curve method used in design of laterally loaded drilled shafts in soil is adopted in the design of such shafts in jointed rock. The p-y curve method treats the soil as a continuum. The continuum model is not applicable to jointed rock, in which the joints form blocks. A new discontinuum model was developed in this thesis to determine the lateral load capacity of drilled shafts in a jointed rock mass with two and three joint sets. It contains two parts: a kinematic and a kinetic analysis. In the kinematic analysis, the removability theorem of a convex block is expanded to analyze the removability of a block intersecting a pile and the removability of a combination of blocks. Based on these removability theorems, a method was developed to select removable combinations of blocks using easily constructed 2-dimensional figures only. In kinetics, each selected removable combination of blocks is analyzed with the limit equilibrium approach to determine the ultimate lateral load capacity. Although the analysis is similar to slope stability analysis, it is more complicated with the addition of a lateral force exerted by the pile and the vertical pile load exerted on the wedge. The analysis also considers the weight of the wedge, the shearing resistance along the joints, and the vertical pile load exerted on the wedge. Simple analytical relations were developed to solve for the ultimate lateral load capacity.
by Albert C. To.
S.M.
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O'Neill, Leah. "Lateral-Torsional Buckling Capacity of Tapered-Flange Moment Frame Shapes." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5759.
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While moment frames are a popular lateral-force resisting system, their constant cross-section can lead to inefficiencies in energy absorption and stiffness. By tapering the flange width linearly toward the center of the beam length, the energy absorption efficiency can be increased, leading to a better elastic response from the beam and more elastic stiffness per pound of steel used. Lateral-torsional buckling is an important failure mode to be considered for tapered-flange moment frame shapes. No closed-form or finite element solutions have yet been developed for tapered-flange I-beams with a non-uniform, linear moment gradient and intermediate bracing conditions. In this study, finite element analysis is used to find the buckling stress of each W-shape in the AISC Steel Construction Manual with both a standard straight-flange and the proposed tapered-flange at several lengths and with three intermediate lateral bracing conditions (no bracing, mid-span bracing, and third-span bracing). Plots are generated for each shape at each bracing condition as the buckling stress versus length for both beams and columns. Overall, the results indicate that lateral-torsional buckling of tapered-flange I-beams is not a problem that would prohibit the wide-scale use of this configuration in moment frames. Also, the buckling capacity tapered-flange moment frame shapes can be reasonably estimated as 20% of the corresponding straight-flange moment frame shape.
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Schreiber, Sascha K. "Punching shear capacity of slab-column connections with steel-fibre reinforcement under lateral cyclic loading." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ60493.pdf.
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Venter, Simon Herman. "The effect of the adjacent span on the lateral-torsional buckling capacity of overhang beams." Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/62800.
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Mirzoyan, Artak Davit. "Lateral Resistance of Piles at the Crest of Slopes in Sand." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd2088.pdf.
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Poulis, Sotiria. "Effectiveness of different treatment regimes on restoring the functional capacity of the ankle following lateral collateral ligament trauma." Thesis, King's College London (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265242.
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Yang, Ke. "ANALYSIS OF LATERALLY LOADED DRILLED SHAFTS IN ROCK." University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1133907777.
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Sathiraju, Venkata Sai Surya Praneeth. "Lateral Stability Analysis of Precast Prestressed Bridge Girders During All Phases of Construction." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1553252005286553.
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Wadi, Husam. "Structural behaviour of lateral load-carrying capacity of timber frame walls filled with hemp concrete : experimental study and numerical analysis." Thesis, Université Clermont Auvergne (2017-2020), 2019. http://www.theses.fr/2019CLFAC038/document.
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Les projets de construction sont aujourd'hui confrontés à des défis importants pour réduire la grande quantité d'énergie employée quotidiennement pour les utilisations tels que le chauffage, l'électricité et l'eau chaude dans les bâtiments résidentiels et commerciaux, en particulier en Europe. De nombreux règlements de construction encouragent l'utilisation des matériaux biosourcés puisqu’ils semblent avoir des propriétés physiques supérieures en terme d'efficacité énergétique dans le secteur de la construction. L'utilisation de matériaux à faible teneur en carbone dans des structures telles que le béton de chanvre améliore le niveau d'isolation ainsi que l'absorption acoustique et diminue le poids de la structure du bâtiment, car ce matériau naturel fournit un agrégat à faible densité. Cette étude concerne le comportement mécanique de murs en bois, réalisés avec des planches croisées en bois CLT et des murs à panneaux d’OSB, sous l’effet de forces horizontales de cisaillement. Une approche théorique a été proposée pour prédire la performance latérale de la paroi CLT par rapport aux charges latérales ainsi qu’une comparaison entre les résultats théoriques et expérimentaux a été effectuée. Des essais expérimentaux ont été réalisés sur des murs de bois ayant deux formes différentes pour étudier et mettre en évidence les paramètres qui affectent significativement la résistance latérale du béton de chanvre en tant que matériau de remplissage. Des montants verticaux et des éléments de contreventement diagonaux de 2,5 mètres de hauteur et 1,25 mètres de largeur soumis à une compression ont été réalisés dans cette étude . Les résultats ont montré que le béton de chanvre apporte une légère contribution contre les charges latérales dans les murs verticaux de 1,25 mètres de largeur, ce qui signifie qu'une diminution de la largeur du mur de bois diminue significativement la contribution du béton de chanvre contre les charges latérales. Trois murs en bois de différentes longueurs (1,2 mètres, 1,6 mètres et 2,4 mètres) remplis de béton de chanvre ont été étudiés numériquement dans cette étude. D'après les résultats numériques, il était évident que la largeur du mur en bois joue un rôle principal dans la résistance latérale du béton de chanvre : lorsque la largeur du mur augmente, la résistance latérale du béton de chanvre s’accroît considérablement. De plus, le contact et la liaison entre le chanvre et les montants en bois affectent totalement la capacité de la résistance latérale du béton de chanvre en tant que matériau de remplissage dans les murs en boisConstruction projects nowadays face significant challenges to reduce the large amounts of daily energy usage for utilities such as heating, electricity and hot water in residential and commercial buildings – especially in Europe. Many building regulations encourage the use of bio-based materials with superior physical properties for energy efficiency in the construction sector. The use of low-carbon material in structures such as hemp concrete, improves the insulation level and sound absorption and simultaneously decreases the weight of the building structure, as this natural material provides low-density aggregate. This study aimed to investigate the mechanical behaviour of timber frame walls against lateral loads. Cross-laminated timber walls (CLT) and Oriented Strand Board (OSB) were used in this study in order to examine the global lateral strength of timber walls. A theoretical approach has been proposed to predict the lateral performance of CLT wall against lateral loads and a comparison between the theoretical and experimental results has been conducted. Experimental testing was undertaken on a full-size example of two different designs of timber walls to investigate and highlight the parameters that significantly affect the lateral resistance of hemp concrete as infill material. Vertical studs and diagonal bracing elements under compression were used in this study, with dimensions of 2.5m height and 1.25m length. The results showed that hemp concrete makes a slight contribution against lateral loads in vertical stud timber wall of length 1.25m, which means that decreasing the length of timber wall significantly decreased the hemp concrete contribution against lateral loads. Three timber walls with different lengths (1.2m, 1.6m and 2.4m) filled with hemp concrete have been examined numerically in this study. Based on the numerical results, it was obvious that the length of the timber wall plays a major role in the lateral strength of hemp concrete, as increasing the wall length significantly increased the lateral strength of hemp concrete. Also, the contact and bonding between hemp material and timber studs significantly affected the lateral load carrying capacity of hemp concrete as infill material in timber frame walls
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Yuan, Zeng. "Advanced Analysis of Steel Frame Structures Subjected to Lateral Torsional Buckling Effects." Queensland University of Technology, 2004. http://eprints.qut.edu.au/15980/.
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The current design procedure for steel frame structures is a two-step process including an elastic analysis to determine design actions and a separate member capacity check. This design procedure is unable to trace the full range of load-deflection response and hence the failure modes of the frame structures can not be accurately predicted. In recent years, the development of advanced analysis methods has aimed at solving this problem by combining the analysis and design tasks into one step. Application of the new advanced analysis methods permits a comprehensive assessment of the actual failure modes and ultimate strengths of structural steel systems in practical design situations. One of the advanced analysis methods, the refined plastic hinge method, has shown great potential to become a practical design tool. However, at present, it is only suitable for a special class of steel frame structures that is not subject to lateral torsional buckling effects. The refined plastic hinge analysis can directly account for three types of frame failures, gradual formation of plastic hinges, column buckling and local buckling. However, this precludes most of the steel frame structures whose behaviour is governed by lateral torsional buckling. Therefore, the aim of this research is to develop a practical advanced analysis method suitable for general steel frame structures including the effects of lateral-torsional buckling. Lateral torsional buckling is a complex three dimensional instability phenomenon. Unlike the in-plane buckling of beam-columns, a closed form analytical solution is not available for lateral torsional buckling. The member capacity equations used in design specifications are derived mainly from testing of simply supported beams. Further, there has been very limited research into the behaviour and design of steel frame structures subject to lateral torsional buckling failures. Therefore in order to incorporate lateral torsional buckling effects into an advanced analysis method, a detailed study must be carried out including inelastic beam buckling failures. This thesis contains a detailed description of research on extending the scope of advanced analysis by developing methods that include the effects of lateral torsional buckling in a nonlinear analysis formulation. It has two components. Firstly, distributed plasticity models were developed using the state-of-the-art finite element analysis programs for a range of simply supported beams and rigid frame structures to investigate and fully understand their lateral torsional buckling behavioural characteristics. Nonlinear analyses were conducted to study the load-deflection response of these structures under lateral torsional buckling influences. It was found that the behaviour of simply supported beams and members in rigid frame structures is significantly different. In real frame structures, the connection details are a decisive factor in terms of ultimate frame capacities. Accounting for the connection rigidities in a simplified advanced analysis method is very difficult, but is most critical. Generally, the finite element analysis results of simply supported beams agree very well with the predictions of the current Australian steel structures design code AS4100, but the capacities of rigid frame structures can be significantly higher compared with Australian code predictions. The second part of the thesis concerns the development of a two dimensional refined plastic hinge analysis which is capable of considering lateral torsional buckling effects. The formulation of the new method is based on the observations from the distributed plasticity analyses of both simply supported beams and rigid frame structures. The lateral torsional buckling effects are taken into account implicitly using a flexural stiffness reduction factor in the stiffness matrix formulation based on the member capacities specified by AS4100. Due to the lack of suitable alternatives, concepts of moment modification and effective length factors are still used for determining the member capacities. The effects of connection rigidities and restraints from adjacent members are handled by using appropriate effective length factors in the analysis. Compared with the benchmark solutions for simply supported beams, the new refined plastic hinge analysis is very accurate. For rigid frame structures, the new method is generally more conservative than the finite element models. The accuracy of the new method relies on the user's judgement of beam segment restraints. Overall, the design capacities in the new method are superior to those in the current design procedure, especially for frame structures with less slender members. The new refined plastic hinge analysis is now able to capture four types of failure modes, plastic hinge formation, column buckling, local buckling and lateral torsional buckling. With the inclusion of lateral torsional buckling mode as proposed in this thesis, advanced analysis is one step closer to being used for general design practice.
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Silva, Pedro Cavalheiro Ribeiro da. "Avaliação do efeito \"set-up\" em estacas cravadas em solos argilosos através da teoria da expansão da cavidade cilíndrica." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/3/3145/tde-20012017-092347/.
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Tem sido observado, de longa data, que ensaios de carregamento dinâmico e provas de carga estática realizados em estacas cravadas após diferentes intervalos de tempo da cravação mostram que podem ocorrer variações nas suas capacidades de carga ao longo do tempo, que em certos casos levam ao aumento da resistência do solo e em outros casos resultam na diminuição da resistência do solo. O trabalho apresenta uma revisão bibliográfica do fenômeno de ganho, com o tempo, de resistência de estacas cravadas em solos argilosos conhecido por efeito \"set-up\", cujos principais mecanismos são explicados por teorias relacionadas à variação das pressões neutras, geradas ao redor das estacas durante a cravação. O método adotado nas análises envolve conceitos da teoria da expansão da cavidade cilíndrica, onde o objetivo principal é entender o comportamento de estacas cravadas em solos argilosos, nos quais o efeito \"set-up\" é normalmente mais acentuado. Os fenômenos pertinentes são avaliados através de análises teóricas, usando o método de Randolph, e numéricas, recorrendo ao método dos elementos finitos. Estas análises foram validadas através de modelagens numéricas comparadas a dados de campo apresentados por ETC (Earth Technology Corporation), sendo observada boa aderência entre os dados de campos e os resultados das estimativas teóricas. A aplicação desta metodologia permite estimar variações tanto das tensões radiais efetivas quanto dos atritos laterais unitários em função do tempo, levando em conta dois parâmetros mais relevantes, a saber, resistência não-drenada e coeficiente de adensamento primário horizontal. Comparações são feitas a ensaios de carregamento dinâmico realizados em estacas cravadas em uma obra da Baixada Santista (SP). Os resultados obtidos mostram uma dispersão no ganho das resistências das estacas analisadas, mas com variações dentro de uma faixa de valores relativamente estreita. Além disso, revelam valores teóricos de \"set-up\", relativo a parcela de atrito lateral, em um intervalo entre 2,0 e 2,5 aproximadamente, 20 dias após a cravação. Apesar das dispersões encontradas, inerentes a este tipo de estudo, considera-se que os resultados obtidos significam um importante passo para melhor entendimento do efeito \"set-up\".For a long time, it has been observed that load tests performed on driven piles show that there may be variations in load capacity over time, which in some cases lead to an increase in soil resistance and in other cases result in decrease of soil resistance. In this study, a review is presented about the mechanisms that lead to the gains in pile load capacity with time, known as \"set-up\", whose main mechanisms are explained by theories related to the excess porepressures generated around the piles during installation. The presented method involves the theory of cylindrical cavity expansion, where the main objective is to understand the behavior of driven piles in clayey soils, in which \"Set-up\" is usually more pronounced. The relevant phenomena are evaluated by theoretical analysis, based in Randolph\'s method, and numerical analysis, using the finite element method. These analyzes were validated through numerical analysis compared to field data presented by ETC (Earth Technology Corporation). Good agreement has been observed between field data and the theoretical results. The methodology allows to estimate variations in both the effective radial stress and the unit friction resistance over time, considering two main parameters, undrained shear strength and horizontal coefficient of consolidation. Comparisons are made to dynamic load tests conducted on driven piles located in Santos Coastal Plane (\"Baixada Santista\"), in São Paulo - Brazil. A dispersion in the results of the load capacities has been observed, but within a relatively narrow range of values. In adittion, the theoretical values of lateral \"set-up\" were obtained in a range between 2,0 and 2,5 approximately 20 days after installation. Knowing that dispersions are inherent to this type of study, it is considered that the results imply an important step to a better understanding of the \"set-up\".
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Zuardi, Marina Campos. "Quantificação da lesão neuronal e mielínica na Esclerose Lateral Amiotrófica através da ressonância magnética." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/17/17140/tde-30082012-083717/.
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Introdução: A Esclerose Lateral Amiotrófica (ELA) é uma doença degenerativa e progressiva que afeta neurônios motores da medula espinhal, tronco cerebral e/ ou córtex motor. Sua manifestação clínica é bastante variada, sua etiologia desconhecida e a progressão, fatal. Não existe ainda um tratamento curativo para a ELA, porém alguns medicamentos e a realização de fisioterapia podem auxiliar, fornecendo ao paciente uma melhor qualidade de vida. Objetivos: Testar a hipótese de que técnicas quantitativas de Ressonância Magnética (RM) são eficazes para detectar a lesão neuronal no encéfalo de pacientes com ELA no estágio inicial da doença e, verificar se existe correlação entre a lesão encefálica e a perda funcional do paciente. Dessa forma, pretende-se estabelecer um protocolo capaz de contribuir para o diagnóstico precoce da ELA. Metodologia: Quinze pacientes com diagnóstico de ELA definida ou provável (12 homens e três mulheres), com idade entre 37 e 79 anos e seus respectivos controles foram submetidos a um protocolo de avaliação por RM, que incluiu um estudo estrutural volumétrico e quantitativo do dano neuronal e mielínico por razão de sequências ponderadas em T1 e FLAIR, da Transferência de Magnetização (MT), Relaxometria, Anisotropia Fracionada (FA) e Difusão (DTI), além da Espectroscopia de prótons. Alguns dos sujeitos foram submetidos também à uma avaliação física de força muscular, de funcionalidade através da Amyotrophic Lateral Sclerosis Functional Rating Scale Revised (ALSFRS-R), de qualidade de vida através da Amyotrophic Lateral Sclerosis Assessment Questionnaire (ALSAQ-40) e de quantificação da fadiga pela Fadigue Severity Scale (FSS). Os dados da RM dos dois grupos foram comparados através da análise de variância multi e univariada e submetidos à correção de múltiplas comparações de Bonferroni. Nas variáveis com diferença significante entre os grupos, foi estudada a validade preditiva da medida, calculando-se a área sob a curva ROC e estabelecidos os valores de sensibilidade, especificidade e acurácia. Os dados das escalas foram comparados pelo teste de Mann-Whitney e correlacionados entre si e com as estruturas através da correlação de Spearman. Resultados: As várias técnicas da RM, com exceção da MT, identificaram pelo menos uma estrutura com diferença significante entre os dois grupos, totalizando 11 estruturas mais a razão dos metabólitos NAA/Cre. Os valores de sensibilidade, especificidade e acurácia foram satisfatórios variando entre 0,60 e 1,00 , com destaque para o Volume do Giro Superior Frontal Direito e Giro Superior Frontal Esquerdo que apresentaram valores 1,00 , 0,93 e 0,97 , respectivamente. As escalas ALSFRS-R e ALSAQ-40 apresentaram diferença significativa entre os dois grupos, mas a FSS não apresentou. As escalas apresentaram correlação significativa entre si em quase todos os escores totais e domínios. Já a correlação das escalas com as estruturas foi significativa apenas para o Volume. Conclusões: Técnicas como DTI, FA, Relaxometria e Volume se mostraram mais eficazes no diagnóstico precoce de pacientes com ELA do que as outras. A redução de volume de substância cinzenta se correlacionou positivamente com a ALSFRS-R. Por fim, propomos um protocolo para avaliação de pacientes com ELA, que inclua imagem volumétrica de alta resolução para cálculo da Volumetria e DTI.Introduction: Amyotrophic Lateral Sclerosis (ALS) is a progressive and degenerative disease that affects motor neurons in the spinal cord, brain stem and/ or motor cortex. Their clinical presentation is varied, its unknown etiology and fatal progression. There isnt still a curative treatment for ALS, but some medications and physical therapy can help by providing the patient a better quality of life. Objectives: To test the hypothesis that quantitative techniques of magnetic resonance imaging (MRI) are effective to detect neuronal damage in the brain of patients with ALS at the inicial stage of the disease and see if there is a correlation between brain injury and functional loss of the patient. Thus, we intend to establish a protocol can to contribute to early diagnosis of ALS. Methods: Fifteen patients with definite or probable ALS (12 men and three women) aged between 37 and 79 and their respective controls underwent an MRI evaluation protocol, including a volumetric and quantitative structural study of damage neuronal and myelin by reason of T1-weighted sequences and FLAIR , Magnetization Transfer (MT), Relaxometry, Fractional Anisotropy (FA), Diffusion (DTI) and Proton magnetic resonance spectroscopy. Some of the subjects also underwent a physical assessment of muscle strength, functionality by Amyotrophic Lateral Sclerosis Functional Rating Scale Revised (ALSFRS-R), quality of life through the Amyotrophic Lateral Sclerosis Assessment Questionnaire (ALSAQ-40) and quantification of fatigue by Fadigue Severity Scale (FSS). The MRI data of the two groups were compared using analysis of variance multivariate and univariate and submitted to correction for multiple comparisons of Bonferroni. In the variables with significant differences between groups, we studied the predictive validity of the measure, by calculating the area under the ROC curve and set the sensitivity, specificity and accuracy. The data of the scales were compared using Mann-Whitney test and correlated with each other and with the structures by Spearman correlation. Results: The various MRI techniques, with the exception of MT, identified at least one structure with a significant difference between the two groups, a total of 11 structures over the reason for the metabolites NAA/Cre. The sensitivity, specificity and accuracy were satisfactory ranging from 0.60 to 1.00 , with emphasis on Volume of Gyros Superior Frontal Right and Gyros Superior Frontal Left that averaged 1.00 , 0.93 and 0,97 , respectively. The ALSFRS-R and ALSAQ-40 scales showed significant differences between the two groups, but the FSS did not. The scales were significantly correlated with each other in almost all domains and total scores. The correlation with the structures of the scales was significant only for the Volume. Conclusions: Techniques such as DTI, FA, Relaxometry and Volume are more effective in early diagnosis of ALS patients than others. The decrease in gray matter volume was positively correlated with the ALSFRS-R. Finally, we propose a protocol for evaluation patients with ALS, including high-resolution volumetric image to calculate the Volume and DTI.
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Andrews, Jinsy A., Lisa Meng, Sarah F. Kulke, Stacy A. Rudnicki, Andrew A. Wolff, Michael E. Bozik, Fady I. Malik, and Jeremy M. Shefner. "Association Between Decline in Slow Vital Capacity and Respiratory Insufficiency, Use of Assisted Ventilation, Tracheostomy, or Death in Patients With Amyotrophic Lateral Sclerosis." AMER MEDICAL ASSOC, 2018. http://hdl.handle.net/10150/626557.
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IMPORTANCE The prognostic value of slow vital capacity (SVC) in relation to respiratory function decline and disease progression in patients with amyotrophic lateral sclerosis (ALS) is not well understood. OBJECTIVE To investigate the rate of decline in percentage predicted SVC and its association with respiratory-related clinical events and mortality in patients with ALS. DESIGN, SETTING, AND PARTICIPANTS This retrospective study included 893 placebo-treated patients from 2 large clinical trials (EMPOWER and BENEFIT-ALS, conducted from March 28, 2011, to November 1, 2012, and from October 23, 2012, to March 21, 2014, respectively) and an ALS trial database (PRO-ACT, containing studies completed between 1990 and 2010) to investigate the rate of decline in SVC. Data from the EMPOWER trial (which enrolled adults with possible, probable, or definite ALS; symptom onset within 24 months before screening; and upright SVC at least 65% of predicted value for age, height, and sex) were used to assess the relationship of SVC to respiratory-related clinical events; 456 patients randomized to placebo were used in this analysis. The 2 clinical trials included patients from North America, Australia, and Europe. MAIN OUTCOMES AND MEASURES Clinical events included the earlier of time to death or time to decline in the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) respiratory subdomain, time to onset of respiratory insufficiency, time to tracheostomy, and all-cause mortality. RESULTS Among 893 placebo-treated patients with ALS, the mean (SD) patient age was 56.7 (11.2) years, and the mean (SD) SVC was 90.5%(17.1%) at baseline; 65.5%(585 of 893) were male, and 20.5%(183 of 893) had bulbar-onset ALS. In EMPOWER, average decline of SVC from baseline through 1.5-year follow-up was - 2.7 percentage points per month. Steeper declines were found in patients older than 65 years (-3.6 percentage points per month [P=.005 vs < 50 years and P=.007 vs 50-65 years) and in patients with an ALSFRS-R total score of 39 or less at baseline (-3.1 percentage points per month [P<.001 vs >39]). When the rate of decline of SVC was slower by 1.5 percentage points per month in the first 6 months, risk reductions for events after 6 months were 19% for decline in the ALSFRS-R respiratory subdomain or death after 6 months, 22% for first onset of respiratory insufficiency or death after 6 months, 23% for first occurrence of tracheostomy or death after 6 months, and 23% for death at any time after 6 months (P<.001 for all). CONCLUSIONS AND RELEVANCE The rate of decline in SVC is associated with meaningful clinical events in ALS, including respiratory failure, tracheostomy, or death, suggesting that it is an important indicator of clinical progression.
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Carretta, Mariana da Silva. "Comportamento de um solo residual levemente cimentado : estimativa de capacidade de carga para estacas submetidas a esforços transversais." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/178393.
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Fundações profundas, quando solicitadas ao carregamento lateral, são regidas por três critérios de projeto: resistência última do solo, carga última do elemento estrutural e deflexão máxima. Esses critérios atuam em conjunto e é necessário que sejam analisados dessa forma, visto que a falha de um deles é capaz de acarretar o colapso de todo sistema. No que tange à resistência do solo, metodologias de capacidade de carga existentes traduzem o comportamento de solos granulares e coesivos. Dada a particularidade da atuação de solos residuais na mecânica dos solos, não há uma metodologia abrangente para estacas sujeitas a solicitação de carregamento lateral nesse tipo de solo, o qual apresenta comportamento intermediário e estrutura levemente cimentada. Em vista disso, o presente trabalho propõe um método de estimativa de capacidade de carga para estacas carregadas horizontalmente, quando inseridas em solo residual e em casos em que as mesmas apresentam topo locado em superfície de solo tratado. Dessa forma, dados de provas de carga lateral pré-existentes e ensaios de laboratório executados ao longo da pesquisa serviram como base para a proposição do método, fundamentado no comportamento do material quando solicitado ao carregamento lateral Ensaios de resistência à compressão simples, compressão oedométrica, compressão isotrópica e ensaios triaxiais com medidas de módulo cisalhante demonstram que há um ponto em que se dá a quebra da estrutura cimentada do solo, passando o mesmo a se apresentar num arranjo desestruturado, refletido em maiores deformações. Uma relação linear é capaz de equacionar a capacidade de carga, tanto para estacas inseridas em solo residual quanto para estacas executadas em solo com camada superficial melhorada. Essa relação é estabelecida entre a carga de ruptura das estacas ensaiadas e a área de solo adjacente à mesma, mobilizada pelo carregamento. Os resultados demonstram que a capacidade de carga das estacas estudadas é regida pela tensão de plastificação do material. O equacionamento proposto possibilita a obtenção da carga de ruptura com base em ensaios simples e de fácil execução, tal como o ensaio de resistência à compressão simples que estabelece relação direta com a tensão de plastificação do solo estudado.Deep foundations, when requested to lateral loading, are governed by three design criteria: ultimate soil strength, piles’ ultimate load, and maximum deflection. These criteria act together and must be analyzed in this way, since the failure of one of them is capable of causing the collapse of the entire system. Regarding soil resistance, the current bearing capacity methodologies describe the behavior of granular and cohesive soils. Given the particular behavior of the residual soils in the soil mechanics, there is no comprehensive methodology for piles subject to lateral loads and inserted in this soil type, which presents an intermediate behavior and a lightly cemented structure. Thus, the present work proposes an estimated bearing capacity for crosswise loaded piles, when inserted in residual soil and in soil with the top layer cemented. So, data from preexisting lateral loading tests and laboratory tests, performed during the research, served as a basis for the proposition of the method, based on the behavior of the material when requested to lateral loading Unconfined compression tests, oedometer consolidation tests, isotropic compression, and triaxial tests with measures of shear modulus demonstrate that there is a point where the soil's cemented structure breaks down, presenting itself in a destructured arrangement, reflected by larger strains. A linear relationship is capable of equating the bearing capacity for both, piles inserted in residual soil and piles carried out in soil with improved surface layer. This relationship is established between the rupture load of the piles tested and the area of soil adjacent to it mobilized by the loading. The results shows that the piles' bearing capacity is governed by the yield stress of the material. The proposed equation makes it possible to obtain the rupture load based on simple and easy tests, such as the unconfined compression test that establishes a direct relationship with the yield stress of the studied soil.
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Gamero, Alessandra Costa [UNESP]. "Desempenho operacional de um subsolador de hastes com curvatura lateral (“Paraplow”), em função de diferentes velocidades de deslocamento e profundidades de trabalho." Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/90467.
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A compactação do solo afeta o desenvolvimento das plantas, bem como pode interferir nos níveis de produtividade das culturas. Com o intuito de diminuir o grau de compactação do solo, operações de manejo, como a subsolagem, que visam o rompimento da camada subsuperficial compactada, são realizadas. Este trabalho teve como objetivo estudar o desempenho operacional de um subsolador de hastes com curvatura lateral (“paraplow”), operando a diferentes velocidades de deslocamento do trator e profundidades de trabalho, bem como, avaliar o consumo energético demandado na operação. O experimento foi conduzido na Fazenda Experimental Lageado, pertencente à Faculdade de Ciências Agronômicas - Campus de Botucatu/UNESP, no ano de 2007. O solo da área experimental foi classificado como Nitossolo Vermelho Distroférrico, textura muito argilosa. O delineamento experimental utilizado foi em blocos casualizados e esquema fatorial 3 x 2, com quatro repetições. Os tratamentos foram compostos da combinação de três velocidades de deslocamento definidas em função do escalonamento de marchas do trator utilizado (A1, A2 e B1) e duas profundidades de trabalho do equipamento utilizado para a mobilização do solo (0,25 e 0,35 m). Foram avaliados os dados referentes à mobilização do solo, patinagem dos rodados, capacidade de campo, consumo de combustível, força e potência na barra de tração do trator. Os resultados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey a 5% de probabilidade. Osresultados obtidos permitiram chegar às seguintes conclusões: a) Após a regulagem em condições estáticas, o subsolador manteve as profundidades da subsolagem durante a operação em condições de campo; b) a velocidade de deslocamento não apresentou efeito significativo sobre a área de solo mobilizado; c) a velocidade de deslocamento e a capacidade de campo...
The soil compactness affects the development of the plants, as well as it can interferes in the levels of productivity of the crops. Some soil management operations, like the subsoiling, aims at the breakage of the soil compacted layer. Those operations are made with the purpose to reduce the soil compactness. This research had the objective of studying the operational performance of a subsoiler with a lateral bending (paraplow), operating to different displacement speeds and depths of work, as well as, valuing the demanded energetic consumption in the operation. The experiment carried out in the Experimental Farm Lageado, Agronomic Sciences College in the¨Julio de Mesquita Filho” University (UNESP) – Botucatu Campus /UNESP, in the year of 2007. The soil of experimental area was classified like “Nitossolo Vermelho Distroférrico”, very clay texture. The experimental design was in 3x2 factorial scheme using randomized blocks with four replications. The treatments were composed of the combination of three displacement speeds defined in function of the scheduling of marches of the tractor (A1, A2 and B1) and two work depths of the equipment used for the mobilization of the soil (0,25 and 0,35 m). The works depths were obtained by changing the height of the support of the wheel of the subsoiler, There were valued the data referring to the mobilization of the soil, tractor wheel slip, capacity of field, fuel consumption , strength and power at the bar of traction of the tractor. The results were subjected to variance analysis and the averages compared by Tukey test at 5 % of probability. The gotten results had allowed to arrive at the following conclusions: a) After adjustment in static conditions, the subsoiler maintained the depths of the subsoiling during the operation in field conditions; b) the speed of displacement did not present significant effect on the mobilized area;... (Complete abstract click electronic access below)
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El, Haffar Ismat. "Physical modeling and study of the behavior of deep foundations of offshore wind turbines in sand." Thesis, Ecole centrale de Nantes, 2018. http://www.theses.fr/2018ECDN0021/document.
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La capacité axiale et latérale des pieux foncés dans du sable de Fontainebleau NE34 ont été étudié à l’aide d’essais sur modèles réduits centrifugés. L’effet de la méthode d’installation, de la densité et de la saturation du sable, du diamètre du pieu, de la géométrie de sa pointe (ouvert /fermé) et de sa rugosité sur la capacité axiale a été étudié. Une augmentation significative de la capacité en traction est observée dans les pieux foncés cycliquement, contrairement aux pieux foncés d’une manière monotone à 100 × g. La saturation du sable dense accélère la formation du bouchon lors de l'installation du pieu. L'augmentation de la rugosité du pieu et de la densité du sable accroissent significativement le frottement latéral des pieux testés. Dans tous les cas, les capacités de pieux sont comparées aux codes de dimensionnement des éoliennes offshore. Une étude paramétrique de l'effet de la méthode d'installation, de l'excentricité de la charge et de la saturation du sable sur la réponse latérale des pieux foncés est ensuite réalisée grâce à l'utilisation d'un pieu instrumentée. Le pieu est chargé d’une manière monotone puis un millier de cycles sont appliqués. Une nouvelle méthode a été développée pour la détermination des constantes d'intégration pour déterminer le profil de déplacement latéral du pieu. La méthode d'installation influence directement le comportement global (moment maximum et déplacement latéral) et local (courbes p-y) des pieux. L'effet de l'excentricité de la charge et de la saturation du sable sur le comportement des pieux est également présenté. Dans chaque cas, une comparaison avec les courbes p-y extraites du code DNVGL est réaliséeThe axial and lateral capacity of piles jacked in Fontainebleau sand NE34 are studied using centrifuge modelling at 100×g. The effect of the installation method, sand density and saturation, pile diameter and pile tip geometry (open or closed-ended) and pile roughness on the axial capacity of piles are firstly studied. A significant increase in the tension capacity is observed in cyclically-jacked piles unlike piles monotonically jacked at 100×g. The saturation of dense sand accelerates plug formation during pile installation. The increase in pile roughness and sand density increases significantly the shaft resistance of the piles tested here. For all the cases, pile capacities are compared with the current design codes for offshore wind turbines. A parametric study of the effect of the installation method, load eccentricity and sand saturation on the lateral response of jacked piles is then realized using of an instrumented pile. The pile is loaded monotonically, then a thousand cycles are applied. A new methodology has been developed for determining of the constants needed in the integration procedure to identify the lateral displacement profile of the pile. The installation method influences directly the global (maximum moment and lateral displacement) and local behaviour (p-y curves) of the piles. The effect of the load eccentricity and sand saturation on the behaviour of the piles is also presented. In each case a comparison with the p-y curves extracted from the DNVGL code is realized
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Ge, W., K. Chen, Z. Guan, Ashraf F. Ashour, W. Lu, and D. Cao. "Eccentric compression behaviour of concrete columns reinforced with steel-FRP composite bars." Elsevier, 2021. http://hdl.handle.net/10454/18412.
Full textAbstract:
YesEccentric compression behaviour of reinforced concrete (RC) columns reinforced by steel-FRP composite bars (SFCBs) was investigated through experimental work and theoretical analyses. The tension and compression test results show that SFCBs demonstrate a stable post-yield stiffness. The mechanical properties of the composite reinforcement have a significant influence on eccentric compression behaviour of the reinforced concrete columns, in terms of failure mode, crack width, deformation and bearing capacity. Formulae were also developed to discriminate failure mode and to determine moment magnification factor, bearing capacity and crack width of the columns studied, with the theoretical predictions being in a good agreement with the experimental results. In addition, parametric studies were conducted to evaluate the effects of mechanical properties of reinforcement, reinforcement ratio, eccentricity, slenderness ratio, types of reinforcement and concrete on the eccentric compression behaviour of RC columns. The results show that the compressive performance is significantly improved by using the high performance concrete, i.e. reactive powder concrete (RPC) and engineered cementious composites (ECC).
financial supports of the work by the National Natural Science Foundation of China (51678514), the Natural Science Foundation of Jiangsu Province, China (BK20201436), the China Postdoctoral Science Foundation (2018M642335), the Science and Technology Project of Jiangsu Construction System (2018ZD047), the Deputy General Manager Science and Technology Project of Jiangsu Province (FZ20200869), the Cooperative Education Project of Ministry of Education, China (201901273053), the Blue Project Youth Academic Leader of Colleges and Universities in Jiangsu Province (2020), the Six Talent Peaks Project of Jiangsu Province (JZ-038, 2016), the Yangzhou University Top Talents Support Project and the Jiangsu Government Scholarship for Overseas Studies.
The full-text of this article will be released for public view at the end of the publisher embargo on 3 Apr 2022.
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Valverde, Rafael Marin. "Envoltória máxima de resistência lateral em estacas através do ensaio de carregamento dinâmico com energia crescente." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3145/tde-28022018-135052/.
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A capacidade de carga de estacas pode ser determinada experimentalmente através de provas de cargas estáticas ou de ensaios de carregamentos dinâmicos, conforme as prescrições da NBR 6122:2010. Na sua forma tradicional, o ensaio de carregamento dinâmico, fundamentado na teoria da equação da onda unidimensional, consiste em aplicar uma sequência de golpes de energia aproximadamente constante no conjunto de amortecedores colocado sobre a estaca e medir, no seu topo, valores de deformação específica e aceleração em função do tempo. Esse ensaio evoluiu ao longo dos anos com o avanço da tecnologia e com o desenvolvimento de modelos numéricos, que permitem simular a prova de carga estática na estaca ensaiada dinamicamente. Outra evolução, uma verdadeira \"revolução\", foi a introdução do método de energia crescente proposto por Aoki (1989). O presente estudo é uma iniciativa de aprofundamento do método de energia crescente com foco na definição da envoltória máxima de resistência lateral, permitindo recuperar as mobilizações dos atritos no fuste da estaca, perdidas em golpes anteriores ao de máxima energia aplicada, principalmente em camadas próximas ao topo da estaca. Este procedimento foi denominado Método da Envoltória Máxima de Resistência Lateral. É apresentada uma revisão bibliográfica envolvendo provas de cargas estáticas e ensaios de carregamentos dinâmicos para determinar a capacidade de carga em estacas, junto com os métodos analíticos, empíricos e semiempíricos, disponíveis na literatura técnica. São apresentados três estudos de casos de obras no Estado de São Paulo, nos quais foram realizados ensaios estáticos e dinâmicos nas mesmas estacas, sendo 2 pré-moldadas e uma escavada. A aplicação do Método da Envoltória Máxima de Resistência Lateral conduziu a uma definição de maiores capacidades de carga através do CAPWAP, com curvas carga-recalque simuladas aderentes às das provas de cargas estáticas. Além disso, permitiu estimativas mais precisas do efeito de \"setup\" a longo prazo e forneceu maiores detalhes a respeito do comportamento do sistema estaca-solo.The load capacity of piles can be experimentally determined through static load tests or high strain dynamic load tests, as stated with the requirements of NBR 6122:2010. In its traditional form, the dynamic load test, based on the theory of the one-dimensional wave equation, consists of applying a sequence of constant energy blows upon the pile, and by these blows are measured values of deformation and acceleration as a function of time. The traditional method has evolved through technological advances along the years, with the development of numerical models that simulate the static load test of a pile dynamically tested. Another evolution, a true called \"revolution\", was the introduction of a method of increasing energy test created and proposed by Aoki (1989). The traditional method has evolved through technological advances along the years. The present study is an initiative to deepen the increasing energy method focusing on the definition of the maximum lateral resistance envelope, allowing recovering the mobilized resistance along the shaft, lost in blows prior to the maximum applied energy, especially in layers close to the top of the pile. This procedure was called the Maximum Envelope of Shear Strength. A review is presented involving static load tests and dynamic load tests to determine the load capacity on piles, together with the analytical, empirical and semi empirical methods available in the literature. Three case studies from the State of São Paulo are presented, where static and dynamic tests were performed on the same piles, two driven and one cast-in-place piles. The application of the Maximum Envelope of Shear Strength led to a definition of higher load capacities through the CAPWAP, with simulated load-displacement curves with good correlations in comparison with the static load tests. In addition, it allowed for more accurate estimates of the long-term \"set-up\" effect and provided more detail about the behavior of the pile-soil system.
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Gamero, Alessandra Costa 1981. "Desempenho operacional de um subsolador de hastes com curvatura lateral ("Paraplow"), em função de diferentes velocidades de deslocamento e profundidades de trabalho /." Botucatu : [s.n.], 2008. http://hdl.handle.net/11449/90467.
Full textAbstract:
Orientador: Sérgio Hugo BenezBanca: Elcio Hiroyoshi Yano
Banca: Paulo Roberto Arbex Silva
Resumo: A compactação do solo afeta o desenvolvimento das plantas, bem como pode interferir nos níveis de produtividade das culturas. Com o intuito de diminuir o grau de compactação do solo, operações de manejo, como a subsolagem, que visam o rompimento da camada subsuperficial compactada, são realizadas. Este trabalho teve como objetivo estudar o desempenho operacional de um subsolador de hastes com curvatura lateral ("paraplow"), operando a diferentes velocidades de deslocamento do trator e profundidades de trabalho, bem como, avaliar o consumo energético demandado na operação. O experimento foi conduzido na Fazenda Experimental Lageado, pertencente à Faculdade de Ciências Agronômicas - Campus de Botucatu/UNESP, no ano de 2007. O solo da área experimental foi classificado como Nitossolo Vermelho Distroférrico, textura muito argilosa. O delineamento experimental utilizado foi em blocos casualizados e esquema fatorial 3 x 2, com quatro repetições. Os tratamentos foram compostos da combinação de três velocidades de deslocamento definidas em função do escalonamento de marchas do trator utilizado (A1, A2 e B1) e duas profundidades de trabalho do equipamento utilizado para a mobilização do solo (0,25 e 0,35 m). Foram avaliados os dados referentes à mobilização do solo, patinagem dos rodados, capacidade de campo, consumo de combustível, força e potência na barra de tração do trator. Os resultados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey a 5% de probabilidade. Osresultados obtidos permitiram chegar às seguintes conclusões: a) Após a regulagem em condições estáticas, o subsolador manteve as profundidades da subsolagem durante a operação em condições de campo; b) a velocidade de deslocamento não apresentou efeito significativo sobre a área de solo mobilizado; c) a velocidade de deslocamento e a capacidade de campo... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The soil compactness affects the development of the plants, as well as it can interferes in the levels of productivity of the crops. Some soil management operations, like the subsoiling, aims at the breakage of the soil compacted layer. Those operations are made with the purpose to reduce the soil compactness. This research had the objective of studying the operational performance of a subsoiler with a lateral bending (paraplow), operating to different displacement speeds and depths of work, as well as, valuing the demanded energetic consumption in the operation. The experiment carried out in the Experimental Farm Lageado, Agronomic Sciences College in the¨Julio de Mesquita Filho" University (UNESP) - Botucatu Campus /UNESP, in the year of 2007. The soil of experimental area was classified like "Nitossolo Vermelho Distroférrico", very clay texture. The experimental design was in 3x2 factorial scheme using randomized blocks with four replications. The treatments were composed of the combination of three displacement speeds defined in function of the scheduling of marches of the tractor (A1, A2 and B1) and two work depths of the equipment used for the mobilization of the soil (0,25 and 0,35 m). The works depths were obtained by changing the height of the support of the wheel of the subsoiler, There were valued the data referring to the mobilization of the soil, tractor wheel slip, capacity of field, fuel consumption , strength and power at the bar of traction of the tractor. The results were subjected to variance analysis and the averages compared by Tukey test at 5 % of probability. The gotten results had allowed to arrive at the following conclusions: a) After adjustment in static conditions, the subsoiler maintained the depths of the subsoiling during the operation in field conditions; b) the speed of displacement did not present significant effect on the mobilized area;... (Complete abstract click electronic access below)
Mestre
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Ebrahim, I. "The lateral load carrying capacity of wall ties used in cavity wall construction in the Western Cape : a comparison between the Butterfly-type wire tie and the Crimped-type wire tie." Master's thesis, University of Cape Town, 2002. http://hdl.handle.net/11427/7703.
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Bibliography: leaves 69-71.The aim of the testing was to compare the relative positives and negatives of the Butterfly Tie and the Crimped lie as regards to water transfer, tensile and compression strengths based on the Australian Code [AS 2699-l 984] requirements as it is more comprehensive. The reason was because the Butterfly Tie has been promoted in cavity wall construction in South Africa for a number of reasons, for example: * NHBRC (National Home Builders Registration Council) compels contractors to use the Butterfly Tie * SABS 28:l986 and SABS O 164-1 :1980 also compel the use of Butterfly Tie, even though there is an anomalous statement in the specifications. Another reason was because the use of the Crimped Tie was not being promoted in cavity wall construction in South Africa mainly because of a lack of information regarding characteristic strength and its resistance to water transfers. The following tests, based on the Australian Code, which is more stringent than the South African Codes were then carried out on the Butterfly Tie and the Crimped Tie: * Tests for water transfer * Tests tor compression and tensile strengths using couplets * Tests for compression and tensile strengths using ties only. Although the testing showed that the Butterfly Tie and the Crimped Tie fulfilled the requirements of the Australian Code, there were negative aspects relating to the Butterfly Tie. It is recommended that serious considerations be given by the South African Bureau of Standards to include the Crimped Tie in its Code of Practice for Cavity Walls.
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Erguner, Kamil. "Analytical Examination Of Performance Limits For Shear Critical Reinforced Concrete Columns." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12611220/index.pdf.
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Most of the older reinforced concrete (RC) buildings have columns that are deficient
when the current code requirements are considered. Therefore, performance of the columns
determines the performance of the structure under the effects of earthquake induced lateral
loads. It is recognized that no provision is proposed in TEC2007 to estimate the failure type
called flexure-shear. Behavior of columns having probability of failing in flexure-shear
failure mode is mostly underestimated by TEC2007 procedures. In addition, failure type
classification of columns performed according to the linear and nonlinear procedures of
TEC2007 needs to be examined with respect to the test results to cover all failure types
including flexure-shear failure in order to lead the engineers develop economical and
realistic retrofit solutions.
In this study, different methods are explored to obtain reliable estimates for the
performance of code deficient shear critical RC columns. Special considerations are given to
Axial-Shear-Flexure interaction (ASFI) approach due to its mechanical background.
After examination of different approaches, ASFI method with proposed
modifications was selected as the most reliable model and lateral load-displacement analyses
were performed on a database of shear critical columns. Findings were compared with the
estimations of the nonlinear procedure given in Turkish Earthquake Code (TEC2007) for
database columns. In addition, drift capacity equations and simplified safe drift capacity
equations are proposed in light of statistical studies on the selected column specimens.
In the last part of the study, performance evaluation of columns according to
nonlinear procedures of FEMA 356, TEC2007, ASCE/SEI 41 update supplement, and
EUROCODE 8 were conducted.
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Cabette, Jean Felix. "Análise dos métodos semi-empíricos utilizados para a estimativa da capacidade de carga de estacas pré-fabricadas com base em resultados de ensaios de carregamento dinâmico." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/3/3145/tde-29122014-172152/.
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A fundação profunda tem como objetivo realizar a transferência das cargas provenientes da superestrutura ao solo, ou seja, deve-se considerar sempre a interação fundação-solo, para estimativa da capacidade de carga de suporte da estrutura. Segundo Avelino (2006) com o surgimento dos ensaios de carregamento dinâmico, o controle do estaqueamento de fundações profundas desenvolveu-se significativamente nos últimos vinte anos devido à facilidade na execução desses ensaios e seu relativo baixo custo. No Brasil, há um predomínio praticamente absoluto dos métodos CASE e CAPWAP. O trabalho tem por objetivo analisar o método semi-empírico que preveja com maior confiabilidade a capacidade de carga de estacas pré-fabricadas cravadas em região de solo mole. Para atingir este objetivo serão analisadas estacas de concreto protendido com seção transversal quadrada 230mmx230mm, utilizadas como fundação de habitações populares em uma obra promovida pela Companhia de Desenvolvimento Habitacional e Urbano do Estado de São Paulo (CDHU), na cidade de Cubatão, São Paulo. Neste trabalho serão apresentados os resultados de capacidade de carga das estacas determinados através da aplicação de alguns métodos consagrados, como o Decourt-Quaresma (1978) e Aoki-Velloso (1975), que utilizam resultados de sondagens a percussão de simples reconhecimento. Estes valores de capacidade de carga serão comparados aos obtidos através de uma série de ensaios de carregamento dinâmico tendo como foco a capacidade de carga da estaca, através das analises CAPWAP. Estes ensaios são localizados próximos aos respectivos furos de sondagens cujos resultados foram utilizados para previsão da capacidade de carga.A deep foundation is a structural element that aims to conduct the transfer of loads from the superstructure to the ground, ie, one should always consider the foundation-soil interaction to predict the load capacity of the frame support. According to Avelino (2006) with the emergence of dynamic loading tests, the control staking of deep foundations has developed significantly over the last twenty years due to the ease in performing those tests and their relative low cost. In Brazil, there is an almost absolute predominance of CASE and CAPWAP methods. The work aims to compare the values of load capacity predicted by semi-empirical methods of prefabricated concrete piles driven in to the soft soil with the values obtained through dynamic load tests. For this, pre-stressed concrete piles were analyzed with square cross section 230mmx230mm, used as popular housing foundation in a project promoted by the Company of Housing and Urban Development of the State of São Paulo (CDHU) in the city of Cubatão, São Paulo. The semi-empiric methods used follow the Decourt and Quaresma (1978), Aoki and Velloso (1975), methods, using results of standard penetration test (SPT). These load capacity values will be compared to those obtained through a series of dynamic loading test focusing on the load capacity obtained through the CAPWAP analysis.
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Wanniarachchi, Somadasa. "Flexural behaviour and design of cold-formed steel beams with rectangular hollow flanges." Queensland University of Technology, 2005. http://eprints.qut.edu.au/29810/.
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Until recently, the hot-rolled steel members have been recognized as the most popular and widely used steel group, but in recent times, the use of cold-formed high strength steel members has rapidly increased. However, the structural behavior of light gauge high strength cold-formed steel members characterized by various buckling modes is not yet fully understood. The current cold-formed steel sections such as C- and Z-sections are commonly used because of their simple forming procedures and easy connections, but they suffer from certain buckling modes. It is therefore important that these buckling modes are either delayed or eliminated to increase the ultimate capacity of these members. This research is therefore aimed at developing a new cold-formed steel beam with two torsionally rigid rectangular hollow flanges and a slender web formed using intermittent screw fastening to enhance the flexural capacity while maintaining a minimum fabrication cost. This thesis describes a detailed investigation into the structural behavior of this new Rectangular Hollow Flange Beam (RHFB), subjected to flexural action The first phase of this research included experimental investigations using thirty full scale lateral buckling tests and twenty two section moment capacity tests using specially designed test rigs to simulate the required loading and support conditions. A detailed description of the experimental methods, RHFB failure modes including local, lateral distortional and lateral torsional buckling modes, and moment capacity results is presented. A comparison of experimental results with the predictions from the current design rules and other design methods is also given. The second phase of this research involved a methodical and comprehensive investigation aimed at widening the scope of finite element analysis to investigate the buckling and ultimate failure behaviours of RHFBs subjected to flexural actions. Accurate finite element models simulating the physical conditions of both lateral buckling and section moment capacity tests were developed. Comparison of experimental and finite element analysis results showed that the buckling and ultimate failure behaviour of RHFBs can be simulated well using appropriate finite element models. Finite element models simulating ideal simply supported boundary conditions and a uniform moment loading were also developed in order to use in a detailed parametric study. The parametric study results were used to review the current design rules and to develop new design formulae for RHFBs subjected to local, lateral distortional and lateral torsional buckling effects. Finite element analysis results indicate that the discontinuity due to screw fastening has a noticeable influence only for members in the intermediate slenderness region. Investigations into different combinations of thicknesses in the flange and web indicate that increasing the flange thickness is more effective than web thickness in enhancing the flexural capacity of RHFBs. The current steel design standards, AS 4100 (1998) and AS/NZS 4600 (1996) are found sufficient to predict the section moment capacity of RHFBs. However, the results indicate that the AS/NZS 4600 is more accurate for slender sections whereas AS 4100 is more accurate for compact sections. The finite element analysis results further indicate that the current design rules given in AS/NZS 4600 is adequate in predicting the member moment capacity of RHFBs subject to lateral torsional buckling effects. However, they were inadequate in predicting the capacities of RHFBs subject to lateral distortional buckling effects. This thesis has therefore developed a new design formula to predict the lateral distortional buckling strength of RHFBs. Overall, this thesis has demonstrated that the innovative RHFB sections can perform well as economically and structurally efficient flexural members. Structural engineers and designers should make use of the new design rules and the validated existing design rules to design the most optimum RHFB sections depending on the type of applications. Intermittent screw fastening method has also been shown to be structurally adequate that also minimises the fabrication cost. Product manufacturers and builders should be able to make use of this in their applications.
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Cheng, Shanshan. "Fire performance of cold-formed steel sections." Thesis, University of Plymouth, 2015. http://hdl.handle.net/10026.1/3316.
Full textAbstract:
Thin-walled cold-formed steel (CFS) has exhibited inherent structural and architectural advantages over other constructional materials, for example, high strength-to-weight ratio, ease of fabrication, economy in transportation and the flexibility of sectional profiles, which make CFS ideal for modern residential and industrial buildings. They have been increasingly used as purlins as the intermediate members in a roof system, or load-bearing components in low- and mid-rise buildings. However, using CFS members in building structures has been facing challenges due to the lack of knowledge to the fire performance of CFS at elevated temperatures and the lack of fire design guidelines. Among all available design specifications of CFS, EN1993-1-2 is the only one which provided design guidelines for CFS at elevated temperatures, which, however, is based on the same theory and material properties of hot-rolled steel. Since the material properties of CFS are found to be considerably different from those of hot-rolled steel, the applicability of hot-rolled steel design guidelines into CFS needs to be verified. Besides, the effect of non-uniform temperature distribution on the failure of CFS members is not properly addressed in literature and has not been specified in the existing design guidelines. Therefore, a better understanding of fire performance of CFS members is of great significance to further explore the potential application of CFS. Since CFS members are always with thin thickness (normally from 0.9 to 8 mm), open cross-section, and great flexural rigidity about one axis at the expense of low flexural rigidity about a perpendicular axis, the members are usually susceptible to various buckling modes which often govern the ultimate failure of CFS members. When CFS members are exposed to a fire, not only the reduced mechanical properties will influence the buckling capacity of CFS members, but also the thermal strains which can lead additional stresses in loaded members. The buckling behaviour of the member can be analysed based on uniformly reduced material properties when the member is unprotected or uniformly protected surrounded by a fire that the temperature distribution within the member is uniform. However if the temperature distribution in a member is not uniform, which usually happens in walls and/or roof panels when CFS members are protected by plaster boards and exposed to fire on one side, the analysis of the member becomes very complicated since the mechanical properties such as Young’s modulus and yield strength and thermal strains vary within the member. This project has the aim of providing better understanding of the buckling performance of CFS channel members under non-uniform temperatures. The primary objective is to investigate the fire performance of plasterboard protected CFS members exposed to fire on one side, in the aspects of pre-buckling stress distribution, elastic buckling behaviour and nonlinear failure models. Heat transfer analyses of one-side protected CFS members have been conducted firstly to investigate the temperature distributions within the cross-section, which have been applied to the analytical study for the prediction of flexural buckling loads of CFS columns at elevated temperatures. A simplified numerical method based on the second order elastic – plastic analysis has also been proposed for the calculation of the flexural buckling load of CFS columns under non-uniform temperature distributions. The effects of temperature distributions and stress-strain relationships on the flexure buckling of CFS columns are discussed. Afterwards a modified finite strip method combined with the classical Fourier series solutions have been presented to investigate the elastic buckling behaviour of CFS members at elevated temperatures, in which the effects of temperatures on both strain and mechanical properties have been considered. The variations of the elastic buckling loads/moments, buckling modes and slenderness of CFS columns/beams with increasing temperatures have been examined. The finite element method is also used to carry out the failure analysis of one-side protected beams at elevated temperatures. The effects of geometric imperfection, stress-strain relationships and temperature distributions on the ultimate moment capacities of CFS beams under uniform and non-uniform temperature distributions are examined. At the end the direct strength method based design methods have been discussed and corresponding recommendations for the designing of CFS beams at elevated temperatures are presented. This thesis has contributed to improve the knowledge of the buckling and failure behaviour of CFS members at elevated temperatures, and the essential data provided in the numerical studies has laid the foundation for further design-oriented studies.
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Gomez, Ariza David. "Etude de la sensibilité au vent latéral d'un mini-drone à capacité de vol stationnaire." Thesis, Toulouse, ISAE, 2013. http://www.theses.fr/2013ESAE0038/document.
Full textAbstract:
Dans l’évolution actuelle de mini-drones à décollage et atterrissage vertical, configurations convertibles de type “tilt-rotors” et “tilt-body” sont de plus en plus souvent utilisées. Ces configurations se sont avérées être très sensibles à l’effet du vent latéral quand ils sont en vol de transition ou tout simplement en vol à basse vitesse. Pour cette raison, une bonne compréhension du comportement d’un proprotor et de l’interaction proprotor-voilure à incidence est nécessaire pour la conception de ce type de drones. Un modèle à l’échelle du mini-drone MiniREC a été testée à la soufflerie S4 de type Eiffel de l’ISAE pour comprendre le comportement de la charge aérodynamique du proprotor au cours de la transition du vol vertical au vol horizontal. Aussi, pour observer l’effet d’échelle et étudier le type de proprotor utilisé normalement par les MAV, une deuxième expérience pour proprotors à incidence a été réalisée à la soufflerie SaBRE. Un anémomètre à film chaud a été utilisé pour caractériser le sillage de l’hélice. Les résultats expérimentaux ont montré la grande incidence de ces forces sur la stabilité longitudinale du drone à des angles d’incidence élevés. Il a également été montré que l’écoulement généré par un proprotor au incidence est de nature très instable, cequi rend sa modélisation complexe. D’un point de vue numérique, l’étude de l’hélice à l’incidence a été faite en utilisant l’hypothèse de Glauert pour un disque actuateur au incidence. Les résultats analytiques sont comparés avec les résultats expérimentaux obtenus à partir des mesures à film chauden 2D et une simulation CFD d’un disque actuateur au incidence chargé avec une charge moyenne équivalente aux valeurs de poussée expérimentales SaBRE et une simulation URANS CFD de l’hélice complète. En outre, les résultats de l’expérience S4 ont été comparés au modèle de Ribner pour les hélices en lacet et le modèle de Young qui est une modification statistique de l’analyse Ribner. La modification proposée du modèle de Ribner donne de bons résultats pour les rotors seul, même à des angles d’attaque élevés. Toutefois, il a été clairement démontré que son amélioration ou un nouveau modèle sont nécessaires afin de prévoir correctement la poussée et les forces produites par proprotors simples et co-axiaux. Pour cela un méthode quasi-stationnaire du premier ordre basée sur la théorie de la dynamique des éléments pales a été développée. Enfin, un prototype aérodynamique avec une sensibilité réduite au vent latéral a été conçu, construit et testé dans la soufflerie S4. Le test a montré que la première conclusion à propos de la contribution du proprotor à la sensibilité longitudinaletotale des mini-drones était justifiée et que la nouvelle configuration fait un candidat idéal pour lesconceptions futures de mini-drones basculant à décollage et atterrissage verticalIn the current development of VTOL mini-UAS and MAVs, configurations like tilt proprotors and tilt-body are being applied more and more often. These types of configurations have shown to be very sensitive to the effect of the lateral wind when they are in transition flight or simply in low speed flight. For this reason a correct understanding of the behavior of a proprotor and the proprotor-wing interaction at incidence is necessary for the design and conception of this type ofUAS. A scaled model of the MiniREC mini-UAS was tested at the ISAE S4 Eiffel type wind tunnel to understand the aerodynamic load behavior of the proprotor during the transition from vertical flight to horizontal flight. Also, to observe the effect of the scale and study the type of proprotor usednormally by MAVs, a second experiment for proprotors at incidence was conducted at the SaBRE wind tunnel. A hot film anemometer was used to characterize the propeller wake. The experimental results showed the great impact of these loads over the longitudinal stability of the drone at highangles of incidence. It was also shown that the nature of the flow for a proprotor at incidence ishighly unsteady which makes its modeling a complex process. From a numerical point of view the study of the propeller at incidence was done using the Glauert’s hypothesis for an actuator disk at incidence. The analytic results are compared with experimental results obtained from the 2D hot film measurements and a CFD simulation of an actuator disk at incidence loaded with a mean load equivalent to experimental SaBRE thrust values and URANS CFD simulation of the full propeller. The results of the S4 experiment were also compared to Ribner’s model for propellers in yaw and the Young’s model which is a statistical modification of Ribner’s analysis. The present modification of Ribner’s model gives good results for single rotors even at high angles of attack. However it wasclearly shown that some improvement or a new model were needed to correctly predict the thrustand the off-axis loads produced by single and coaxial proprotors. For this a first order quasi-steady method based on blade element momentum theory was developed. Finally an aerodynamic prototype(with reduced sensitivity to the lateral wind) was designed on these bases, built and tested in theS4 wind-tunnel. The test showed that the initial conclusion about the contribution of the proprotorto the total longitudinal sensitivity of the mini-UAS were justified and that the new configuration showed a reduced sensitivity to the lateral wind which makes it a perfect candidate for future designs of tilt-body VTOL mini-UAS
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Cunin, Bernard. "Etude et realisation d'un modulateur parametrique a double bande laterale fonctionnant a 10 ghz : application a la detection d'impulsions lumineuses breves." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13127.
Full textAbstract:
Les proprietes d'un modulateur parametrique sont analysees. On montre que ce dispositif, constitue par la capacite variable d'une jonction pn pompee a 10 ghz, est caracterise par un gain de conversion, une impedance d'entree capacitive et un bruit interne tres reduit et qu'en consequence un systeme de detection optique, forme par une diode pin rapide couplee au convertisseur parametrique, presente un rapport signal a bruit superieur a celui des dispositifs de detection sans amplification interne habituellement utilises, au moins tant que la bande passante video est inferieure a 4 ghz. Enfin, on decrit une realisation pratique pour laquelle on a mesure un gain de conversion de 7db et une largeur a mi-hauteur de la reponse percussionnelle du modulateur seul voisine de 500 ps
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Green, Marcus. "Social networks and residential mobility in later life : the effects of moving on social network supportive capacity amongst older people in the UK." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/368007/.
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This is an interdisciplinary PhD research project, spanning the ESRC Centre for Population Change and the Centre for Research on Ageing. Using British Household Panel Survey data, the thesis aims to prove that undertaking a residential move changes the supportive capacity of one’s social network in later life. The study first investigates the determinants of moving home in later life. It then conceptualises and constructs the social networks of older people in the UK, considering key attributes such as network size, frequency, proximity and functions and examines the effects of moving home on these measures. The analysis finds that the incidence of residential mobility is associated with, amongst other things, becoming widowed and experiencing a negative change in health or financial circumstance. Furthermore older people are likely to experience disruption to the supportive capacity of their companionship and community networks following a move. This research has important implications for policy as any damaging effects on an older person’s informal support network may have consequences for their health outcomes and in turn lead to an increased dependence on formal health and social care services at the places to which they move.
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Chvíla, Ladislav. "Vlastnosti fraktálních kapacitorů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219892.
Full textAbstract:
This work is focused on computer simulations of fractal capacitors. The geometry of capacitors and its influence is investigated. Simulations are realized in programs Matlab, SolidWorks and Comsol Multiphysics. There are also several specific examples of different geometrics of capacitors their comparisons and assessment.
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Zaghlool, Baher SalahElDeen Othman Ahmed. "Behaviour of three-dimensional concrete structures under concurrent orthogonal seismic excitations." Thesis, University of Canterbury. Civil Engineering, 2007. http://hdl.handle.net/10092/1177.
Full textAbstract:
This thesis is a study into the response and seismic safety of three-dimensional multi-storey concrete structures under concurrent orthogonal seismic excitations. It employs the nonlinear time-history method as its analysis tools. Time-history analyses rely heavily on their utilised earthquake records. Accordingly, this study examines the different approaches of selecting earthquake suites and develops a methodology of selecting representative earthquake scenarios. This methodology is credibly implemented in selecting a far- and a near field suites representative of the New Zealand seismic hazard. The study investigates the response of 6-, 9- and 12-storey concrete structures of different n-X-bays × m-Y-bays. Bidirectional responses of these considered structures are examined and consequently the current combination rules are scrutinised. Consequently this study strongly recommends the use of the 40-percent combination rule in lieu of the widely used 30-percent rule; and the use of time-history analysis in lieu of quasi/equivalent static and response modal analysis methods to avoid their strong dependence on combination rules. An intensive study is conducted employing the incremental dynamic analysis (IDA) technique to investigate structural demands of interstorey drifts, lateral storey drifts and storey accelerations. The study utilises the developed far-field suite and identifies the 50th and 90th percentile demands. Hence it provides easy-to-use expressions to facilitate rapid calculation of the structural demands and the effects of biaxial interactions. An implementation into the Demand and Capacity Factor Design (DCFD) format is presented that infers confidence in the performance levels of the considered structures. The study also draws attention to the importance of considering storey accelerations as their storey values reach as high as 10 × PGA. A sensitivity study is conducted by repeating the IDA investigation while using the developed near-field suite. Subsequently a comparison between the near- and the far-field results is conducted. The results were markedly similar albeit of less magnitudes until the (seismic hazard) intensity measure IM = Sa(T₁) = 0.4g when the near-field results show sudden flat large increase in demands suggesting a brittle collapse. This is attributed to the higher content of the higher mode frequencies contained in near-field ground motions. Finally, the study examines the (vectorial) radial horizontal shear demands in columns and beam-column joints of the previous far- and near-field studies. The combined radial shear demands in corner, edge and internal columns and joints are evaluated that roughly show a square-root proportional relationship with IM that exhibit somewhat brittle failure at IM ≥ 0.35g. Shears demands in the (4-way) internal columns and the (2-way) corner joints show highest magnitude in their respective class. The results suggest transverse joint shear reinforcement of 1.5, 1.0 and 0.5 of the longitudinal reinforcement of the neighbouring beam respectively for corner, edge and internal joints. An implementation of a proposed practical (and simpler) DCFD format shows satisfactory confidence in columns performance in shear up to IM = 0.35g, conversely to joints unsatisfactory performance in shear at the onset of inelastic behaviour (IM > 0.05g).
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Torres, Rodriguez Luz Maria. "Synthèses et caractérisations électrochimiques de films de polypyrrole fonctionnalisés par des unités biotine : étude de la reconnaissance biotine/avidine." Université Joseph Fourier (Grenoble), 2000. http://www.theses.fr/2000GRE10189.
Full textAbstract:
Ce travail decrit l'elaboration et la caracterisation d'un biocapteur compose d'une matrice polymere, un polymere conducteur electronique le polypyrrole, incluant des molecules de biotine greffees par un lien covalente covalente au polypyrrole. Ce biocapteur est obtenu par electyropolymerisation de monomere pyrrole pre-fonctionnalise par des molecules de biotine. Nous presentons dans une premiere partie la synthese de deux monomeres biotinyles qui sont formes par une unite pyrrole lie a la biotine par l'intermediaire d'un bras espaceur polyether. Ces deux monomeres se differencient par la longueur du bras espaceur qui lie le pyrrole et l'unite biotine, respectivement notes $$1 et $$2 pour la molecule a bras court (14 atomes) et long (21 atomes). Dans la deuxieme partie du travail nous abordons la synthese et la caracterisation electrochimique des films biotinyles en milieu aqueux. Les films sont prepares soit par electrohomopolymerisation des monomeres $$1 et $$2, soit par electrocopolymerisation de $$1 avec du pyrrole ou un n-alkyle pyrrole qui se differencie du monomere $$1 seulement par la substitution de l'entite biotine par un groupement acetamide. Les resultats montrent que la reponse voltamperometrique des films poly$$1 et poly$$2 depend de l'epaisseur du film. En effet, pour des films minces (71 nm) la reponse presente deux pics anodiques tandis que pour films plus epais (242 nm) un seul pic anodique est observe. Ce comportement differe de la reponse electrochimique des autres n-alkyle pyrroles. Dans la derniere partie de ce travail l'immobilisation des molecules d'avidine a ete mise en evidence par microgravimetrie (microbalance a quartz) et voltamperometrie cyclique. D'apres les resultats obtenus par microgravimetrie la longueur du bras espaceur qui lie le pyrrole et l'unite biotine joue un role importante sur la quantite d'avidine immobilisee puisque sur le film poly$$2 deux fois plus de molecules d'avidine sont ancrees par rapport au film poly$$1. D'autre part nous avons montre que la reponse voltamperometrique de ces deux films poly$$1 et poly$$2 est modifiee par l'immobilisation de l'avidine.
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Ou, Chia-Wei, and 歐嘉維. "Effects of Stream Self-purification Capacity by Lateral Constructions." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/78023832835654260872.
Full textAbstract:
碩士逢甲大學
土木及水利工程所
92
River corridors become good habitats of animals and plants living� environment because of the continuity that space and energy delivers. Traditional hydraulic engineering establishing makes the channel effect of river, causing the physical and chemical properties of water body change, habitats lose or the corridors break off, and result in living creature lost. In recent years Taiwan develops ecological methods which include the environmental protection and the resource sustaining to use to purify water quality in streams. Applying ecological methods to dredge rivers or streams, conferring the effect of self-purification property and enhance the factor of purified capability in rivers, becoming new thinking of the river engineering. The results from the experiments showed that the gravel’s hole of steam bed is bigger, the removal rate of organic matters and suspend solids is 22.1%〜24.2% and 42.7%〜49.5%. Establishing lateral constructions in channel will increase the disturbance of water body and enhance the effect of reaeration. The increasing rate of dissolve oxygen is over 20% and providing positive effect upon enhancing dissolve oxygen of water body. The V type of lateral gravel construction makes the effect of water body disturbing better and has the capability of steady flow and decrease stream bank scouring in hydraulic dimension. Disposing pools downstream of lateral constructions has water-cushion function and is better for the removal rate of organic matters. Therefore under the condition of considering water quality, hydraulics and ecosystem, disposing lateral gravel constructions can provide positive effect on purified and multiplicity of stream habitat.
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Wu, Zheng-Yan, and 吳政諺. "Numerical Study for Geosynthetic Reinforced Revetments on Lateral Bearing Capacity." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/93820011009374904289.
Full textAbstract:
碩士國立臺灣大學
土木工程學研究所
104
Geosynthetic-reinforced soil walls can be classified into two types according to the design concept: Mechanically Stabilized Earth Walls (MSEW) and Geosynthetics Reinforced Soil Composites (GRSC). The former is designed and constructed in the same manner as a tied-back wall; while the latter is treated and designed as a composite material. Compared to MSEW, GRSC is more deformable and can withstand higher impact force. In this study, the finite element software, PLAXIS 3D, was used to analyze the behaviors of the GRS barriers under quasi-static lateral pressures induced by debris flows. The influencing factors investigated were as follows: (1) grouted-facing and wrap-around facing barriers; (2) geometry of the barriers; (3) parameters of backfill and reinforcement; (4) load pattern; (5) scouring; (6) debris flow induced shear stress on the facing of the barriers. The results of finite element analysis indicated that the lateral bearing capacity depended on the aspect ratio (W/H: ratio of wall width to wall height), and that the failure mode depended on both facing type and aspect ratio. For grouted facing barriers with W/H < 1.0, they would fail in overturning. For 1.0 < W/H < 3.0, a sliding failure occurred along the backfill-foundation interface. For W/H > 3.0, passive soil failure occurred within the barrier and near the loading side. As for the wrap-around barrier, when W/H < 1.6, sliding failure occurred along the bottom layers of reinforcement. When W/H > 1.6, the ultimate lateral bearing capacity was reached due to local passive soil failure occurred on the top of loading side. The parametric study showed that the W/H ratio, backfill cohesion c, soil unit weight, and friction angle φ were the major influencing factor to the lateral bearing capacity. When the foundation of the barrier was scoured by debris flows, its lateral bearing capacity would decrease 30 to 50%. Considering the shear stress in addition to lateral pressures induced by debris flows, the lateral displacement would be much increased for both types of barrier.
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Hsieh, Jia, and 謝嘉. "Numerical Evaluation of Lateral Bearing Capacity of Geosynthetic-Reinforced Earth Dam." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/r6tz39.
Full textAbstract:
碩士國立臺灣大學
土木工程學研究所
105
The design of geosynthetic-reinforced soil walls can be classified into two types according to the design concept: Mechanically Stabilized Earth Wall (MSEW) and Geosynthetics Reinforced Soil Wall (GRSW). The former is designed and constructed in the same manner as a tied-back wall; while the latter is treated and designed as a composite material. In this study, the finite element software, PLAXIS 3D, was used to analyze the behavior of two types of geosynthetic-reinforced earth dams (open-type and slit-type), which were reinforced with geogrids and geocells, respectively, and subjected to the impact force from debris flows. The influencing factors investigated were as follows: (1) the vertical spacing and zone of reinforcement; (2) scouring; (3) impact from boulders, etc. The result of analysis indicated that deformation of both dam types bulged at their middle heights, with the maximum deformation about 2% of the dam height. Moreover, passive soil failure occurred within the two flanges and in the base of the structure. With the same amount of different reinforcements, the geocell open-type dam displaced less than the geogrid open-type dam, but the difference was not much for slit dams when they were subjected to quasi-static lateral pressures induced by debris flows. In addition, with reduced vertical spacing of geogrid layers, the dam tended to behave as a GRSW and had better resistance to lateral deformation. The effect of scouring in reducing ultimate lateral bearing capacity was more significant for MSEW than GRSW. For open-type dams, the effect of scouring was more serious for geogrid dam than geocell dam. However, the effect was reversed for slit dams. The lateral bearing capacity of geocell slit dam after scouring decreased significantly (about 40%); while that of geogrid dam is only less than 10%.
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Barker, Paul D. (Paul David). "Effects of soil slope on the lateral capacity of piles in cohesionless soils." Thesis, 2012. http://hdl.handle.net/1957/28476.
Full textAbstract:
Deep foundations, including driven piles, are used to support vertical loads of structures and applied lateral forces. Many pile supported structures, including bridges, are subjected to large lateral loads in the form of wind, wave, seismic, and traffic impact loads. In many practical situations, structures subjected to lateral loading are located near or in excavated and fill slopes or embankments. Full-scale research to examine the effects of soil slope on lateral pile capacity is limited. The purpose of this study is to examine the effects on lateral capacity of piles located in or near cohesionless soil slopes.
A full-scale lateral load testing program was undertaken on pipe piles in a cohesionless soil at Oregon State University. Five piles were tested near a 2H:1V test slope and located between 0D to 8D behind the slope crest, where D is the pile diameter. Two vertical baseline piles and three battered piles were also tested in level ground conditions. The cohesionless backfill soil was a well-graded material with a fines content of less than 10% and a relative compaction of 95%, meeting the Caltrans specification for structural backfill.
Data collected from the instrumented piles was used to back calculate p-y curves, load-displacement curves, reduction factors, and load resistance ratios for each pile. The effects of slope on lateral pile capacity are insignificant at displacements of less than 2.0 inches for piles located 2D and further from the crest. For pile located at 4D or greater from the slope crest, the effect of slope is insignificant on p-y curves. A simplified p-multiplier design procedure derived from back-calculated p-y curves is proposed to account for the effects of soil slope.
Comparisons of the full-scale results were made using proposed recommendations from the available literature. Lateral resistance ratios obtained by computer, centrifuge, and small scale-models tend to be conservative and overestimate the effects of slope on lateral capacities. Standard cohesionless p-y curve methods slightly over predict the soil resistance at very low displacements but significantly under predict the ultimate soil resistance. Available reduction factors from the literature, or p-multipliers, are slightly conservative and compare well with the back-calculated p-y curves from this study.Graduation date: 2012
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Lee, Maw Shing, and 李茂興. "Using neural network to estimate lateral capacity of piles and load-displacement measured at pile head when lateral loading is applied." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/16878260075995443327.
Full textAbstract:
碩士國立海洋大學
河海工程學系碩士在職專班
89
Due to the construction of high-rise buildings and bridge piers, deep foundations including driven piles and drilled shafts have become more popular in recent years in Taiwan . How to evaluate lateral capacity of piles has become very important for the geotechnical engineers . In general, at practice we have to either oversimplify natures of the problem by ignoring influences of certain governing factors or perform in-situ pile load tests to obtain P-y curves for lateral capacity evaluation of piles. This research shows that the neural network approach is a reliable alternative method to estimate lateral capacity of piles and load-displacement curves measured at pile head when lateral loading is applied .
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Tang, Bing-Shiun, and 湯秉勳. "Comparision Study on Pseudo-elastic Method for Ultimate Lateral Capacity of Highrise Steel Structures." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/24863516004459254463.
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Ke, jyh-ren, and 柯智仁. "Stability Study for Maximum Lateral Capacity of High-rise Steel Frame by Pusdo-Elastic Approach." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/39116943601412932884.
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Chen, Yi-Shou, and 陳毅修. "Finite Element Study on Lateral Bearing Capacity and Failure Mode of Geosynthetic-Reinforced Soil Barriers." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/99756263332074700405.
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碩士國立臺灣科技大學
營建工程系
102
Geosynthetic-reinforced soil (GRS) structures are often used to carry vertical surcharges. Recently, GRS structures have been applied as barriers to resist lateral force from natural disasters such as flood, tsunami, rock fall, debris flow, and avalanche. In design guideline, the stability of such structures is often evaluated by conducting the conventional external stability analyses assuming the reinforced soil mass as a rigid body. However, the assumption of rigid body contradicts with the flexible nature of reinforced soil. In this study, finite element (FE) models of back-to-back GRS walls were developed to investigate the failure mode and lateral bearing capacity of GRS barriers subjected to lateral loadings. The FE result showed GRS barriers generated bending deformation when subjected to lateral force. As a result, the vertical stress at the side of wall subjected to lateral force decreased due to the bending deformation induced tension stress. On the other hand, the vertical stress at the opposite side increased because of the bending deformation induced compression stress. The failure mode depended on the aspect ratio of GRS barriers L/H (ratio of wall width to wall height). When 0.5 < L/H < 1, the GRS barriers subjected to lateral loading failed internally. Due to the development of bending stress, the GRS barriers failed due to the internal sliding along the soil-reinforcement interface at the side subjected to the lateral force and meanwhile the active failure of reinforced soil wedge at the opposite side. When 1.0 < L/H < 3.0, sliding failure at the bottom of GRS barriers occurred. When L/H > 3.0, the passive soil failure occurred within GRS barriers at the side subjected to the lateral force. The parametric study results indicated the major factor to affect the ultimate lateral bearing capacity was the aspect ratio of GRS barriers. As L/H increases, the lateral bearing capacity of GRS structures increased from approximately twice of active lateral earth pressure at L/H = 0.5 to the passive lateral earth pressure at L/H = 3.0.
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Khalili, Ghomi Shervin. "Seismic performance of GFRP-RC exterior beam-column joints with lateral beams." 2014. http://hdl.handle.net/1993/23304.
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In the past few years, some experimental investigations have been conducted to verify seismic behaviour of fiber reinforced polymer reinforced concrete (FRP-RC) beam-column joints. Those researches were mainly focused on exterior beam-column joints without lateral beams. However, lateral beams, commonly exist in buildings, can significantly improve seismic performance of the joints. Moreover, the way the longitudinal beam bars are anchored in the joint, either using headed-end or bent bars, was not adequately addressed. This study aims to fill these gaps and investigate the shear capacity of FRP-RC exterior beam-column joints confined with lateral beams, and the effect of beam reinforcement anchorage on their seismic behaviour. Six full-scale exterior beam-column joints were constructed and tested to failure under reversal cyclic loading. Test results showed that the presence of lateral beams significantly increased the shear capacity of the joints. Moreover, replacing bent bars with headed-end bars resulted in more ductile behaviour of the joints.
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Chu, Tsu-Hung, and 朱祖宏. "Evaluation of Interpretation Criteria and Capacity for Drilled Shafts in Gravelly Soils under Axial and Lateral Loading." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/02626300806742460847.
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碩士中原大學
土木工程研究所
97
This study is a critical evaluation of drilled shafts under axial and lateral loading in gravelly soils. Both interpretation criteria and analysis methods are examined using field load test data. Available interpretation criteria are used to establish a consistent axial and lateral interpretation criterion. The β method, general bearing capacity equation, and SPT-N empirical equation are evaluated for axial capacity, while the simple Chang method is used for lateral capacity. Based on these analyses, QL1 is close to load at 0.31%B with 2.6 mm and QL2 is close to load at 18.4 mm for uplift loading. QL1 is close to load at 0.54%B with 7.2 mm and QL2 is close to load at 52.1 mm for compression loading. Among all axial interpretation criteria, the Davisson method gives the lowest results and Chin method has the highest results. For lateral loading, QS&W is close to Q0.75%B and Q10.0mm, while QL is close to Q1.2%B and Q11.4mm. For the analysis of axial capacity, the side resistance of β method is generally underestimated and the general bearing capacity equation is overestimated. The suggested SPT-N empirical equations were also evaluated using measured results. For lateral capacity, the statistical data show that the larger the lateral displacement, the closer the results between measurements and simple Chang method. Finally, specific design recommendations for the interpretation and capacity analysis are given.
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Huang, Bo-Chi, and 黃柏齊. "Increase of Storage Capacity for Holographic Data Storage by Lateral Shearing Interferometry with use of Sparse Code." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/2wkj8n.
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碩士國立中央大學
光電科學與工程學系
106
In this thesis, an optical model considering the density of signal is proposed based on lateral shearing interferometry with use of sparse code through LPF. This model is applied to the conjugate of record side in holographic data storage system for analyzing the record point of the holographic disk. With this optical model, the shearing image in different signal density, modulation mode, filter size can be predicted. In simulation and experiment, the increase of storage capacity is at least 1.368 times by the limitation of twice.
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Argudo, Jaime Fernando. "Non-destructive evaluation of gravity load carrying capacity and lateral load damage of reinforced concrete slab-column connections." Thesis, 2006. http://hdl.handle.net/2152/2458.
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Alves, Diogo António da Silva. "Ensaios em modelos reduzidos de sapatas com reforço lateral." Master's thesis, 2014. http://hdl.handle.net/10316/38461.
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Dissertação de Mestrado Integrado em Engenharia Civil apresentada à Faculdade de Ciências e Tecnologia da Universidade de CoimbraNo dimensionamento das fundações superficiais é deveras importante que o projetista defina de forma explícita e objetiva a capacidade de carga e a previsão dos assentamentos. Um dos alicerces, no qual os projetistas se sustentam, é as informações que advém do ensaio de carga em placa. A presente dissertação aborda as questões da capacidade de carga de fundações superficiais com e sem saia estrutural e do comportamento destas em solos com diferentes compacidades. O objetivo fundamental consiste na análise do efeito da saia estrutural na capacidade de carga das fundações superficiais. O estudo deste efeito é desenvolvido através da execução de ensaios de carga em placa em modelos reduzidos, realizados no Laboratório de Geotecnia do Departamento de Engenharia Civil de Coimbra. Numa primeira parte da dissertação é apresentada uma descrição do trabalho laboratorial produzido acerca de ensaios de carga em placa com saia estrutural sob ação de uma carga centrada e de uma carga excêntrica. Posteriormente foi elaborada uma breve introdução ao tema da capacidade de carga em fundações superficiais, onde é exposto a teoria da plasticidade bem como as fórmulas dos vários autores associadas a esta teoria. Seguindo-se a descrição detalhada do programa experimental. O fundamento primordial desta dissertação reside no resultado dos 12 ensaios de carga em placa com e sem saia estrutural sob ação de uma carga centrada. Os resultados obtidos são minuciosamente analisados, com o intuito de satisfazer o objetivo. Neste trabalho existe o cuidado em conceber as conclusões e experiência adquirida de forma a ampliar o conhecimento acerca das fundações superficiais munidas de saias estruturais, ajudar nos trabalhos futuros e estimular o desenvolvimento deste tipo de fundações
Following the design of the shallow foundations it is indeed important that the designer defines in an explicit and objective form the load capacity and prediction of settlements. One of the foundations in which the designer is based on, are the information’s that derives from the plate load test. The present dissertation approaches the matters of load capacity of shallow foundations with and without structural skirt and the behavior from these on soils with different compactness. The main objective consists in the analyses of the effect of structural skirt in load capacity of shallow foundations. The research of this effect is developed through the implementation of plate load tests in scale models, performed at the Laboratory of Geotechnical Engineering, Department of Civil Engineering of Coimbra. In a previous part of the dissertation it is presented a description from a produced laboratory work about a test plate load with structural skirt under the action of a centric load and eccentric load. Afterwards it was produced a brief introduction to the topic of load capacity of shallow foundations, was outlined the theory of plasticity as well as the formulas of the several authors related to this theory. Followed by the detailed description of the experimental program. The main purpose of this thesis lies in the results of the 12 plate load tests with and without structural skirt under the action of a centric load. The results that were obtained with this research were thoroughly analyzed in order to meet the objective. This work cares into conceive the conclusions and experience that were acquired in a way to amply the knowledge about the shallow foundations bearing structural skirts, a support to future works and stimulate the development of this type of foundations
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Lee, Jih Feng, and 李紀鋒. "The study of lateral buckling behavior and load capacity of steel beams with copes in flange and cavities in web." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/05401358862727783954.
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Balakrishnan, Saju [Verfasser]. "The mitochondrial role in calcium metabolism and differential calcium buffering capacity of amyotrophic lateral sclerosis (ALS) vulnerable and resistant motoneurons from mice / vorgelegt von Saju Balakrishnan." 2006. http://d-nb.info/98222379X/34.
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