Dissertations / Theses on the topic 'Arches'

The aim of the present research was to provide a practical theoretical model based on elementary statics, for assessment for masonry arch bridges, that benefits from the large scale experimental programme at Salford University, together with insight gained from the Distinct Element numerical modelling work. The need for large scale laboratory controlled load tests of physical models that may be reliably confined to a specific domain of behaviour with known parameters and modelling constraints, was highlighted in chapter 2 with reference to literature. Load tests on various distributions of surcharge were carried and the mechanisms of failure observed. The numerical modelled was shown to agree with expected theoretical behaviour and shown good agreement with experimental results. A theoretical model was developed which benefitted from insight from the experimental and numerical work to provide a means of predicting the failure load of the arch-fill system for the lading arrangements carried out in the physical and numerical tests. The model provided predicted failure loads for a range of material variation within a reasonable expected range and showed promising resemblance to the physical modelling results.

The advent of Limit States Design has created the necessity for a better understanding of how structures behave when loaded beyond first local yielding and up to collapse. Because the problem of determining the ultimate load capacity of structures is complicated by geometric and material non-linearity, a closed form solution for anything but the simplest of structure is not practical. With this as motivation, the ultimate capacity of fixed arches is examined in this thesis. The results are presented in the form of dimensionless collapse curves. The form of these curves is analogous to column capacity curves in that an ultimate load parameter will be plotted as a function of slenderness. The ultimate capacity of a structure is often determined by Plastic Collapse analysis or Elastic Buckling. Plastic Collapse is attained when sufficient plastic hinges form in a structure to create a mechanism. This analysis has been proven valid for moment resisting frames subjected to large amounts of bending and whose second order effects are minimal. Elastic buckling is defined when a second order structure stiffness matrix becomes singular or negative definite. Pure elastic buckling correctly predicts the ultimate load if all components of the structure remain elastic. This may occur in slender structures loaded to produce large axial forces and small amounts of bending. Because arches are subject to a considerable amount of both axial and bending, it is clear that a reasonable ultimate load analysis must include both plastic hinge formation and second order effects in order to evaluate all ranges of arch slenderness. A computer program available at the University of British Columbia accomplishes the task of combining second order analysis with plastic hinge formation. This ultimate load analysis program, called "ULA", is interactive, allowing the user to monitor the behaviour of the structure as the load level is increased to ultimate. A second order analysis is continually performed on the structure. Whenever the load level is sufficient to cause the formation of a plastic hinge, the stiffness matrix and load vector are altered to reflect this hinge formation, and a new structure is created. Instability occurs when a sufficient loss of stiffness brought on by the formation of hinges causes the determinant of the stiffness matrix to become zero or negative. Two different load cases were considered in this work. These are a point load and a uniformly distributed load. Both load cases included a dead load distributed over the entire span of the arch. The load, either point load or uniform load, at which collapse occurs is a function of several independent parameters. It is convenient to use the Buckingham π Theorem to reduce the number of parameters which govern the behaviour of the system. For both load cases, it was necessary to numerically vary the location or pattern of the loading to produce a minimum dimensionless load. Because of the multitude of parameters governing arch action it was not possible to describe all arches. Instead, the dimensionless behaviour of a standard arch was examined and the sensitivity of this standard to various parameter variations was given. Being three times redundant, a fixed arch plastic collapse mechanism requires four hinges. This indeed was the case at low L/r. However, at intermediate and high values of slenderness, the loss of stiffness due to the formation of fewer hinges than required for a plastic mechanism was sufficient to cause instability. As well, it was determined that pure elastic buckling rarely, if ever, governs the design of fixed arches. Finally, the collapse curves were applied to three existing arch bridges; one aluminum arch, one concrete arch, and one steel arch. The ultimate capacity tended to be between three and five times the service level live loads.
Applied Science, Faculty of
Civil Engineering, Department of
Graduate

The Garpenberg mine, owned by the Boliden Mining group, has established a trial area at Dammsjön orebody in order to examine the possibility of increasing the productivity of the mine. The mine uses the rill mining method with a current rill height of 15 m. In order to increase the productivity, the mine is examining the possibility of increasing the height of the rill. The trial area is located at 882 m depth surrounded by dolomite on the hangingwall and quartzitic rock on the footwall side. Rock support arches have been installed, in addition to the regular support pattern, to test their effectiveness on stabilizing the ground around the drifts. The arches have been installed in every 6 m and every 3 m in different parts of the test area. Rock samples from the trial area were brought to the university laboratory for testing. The data gathered from the laboratory tests along with the data from the monitoring of the trial area were used to develop a calibrated numerical model. A three-dimensional (3-D) model was therefore created, by using the FLAC3D numerical code. After the calibration of the model a parametric study was conducted for different rill heights and different arch spacing to investigate the performance of the arches. Specifically, the case of no arch installation along with the cases of an installed arch every 6 m and 3 m were tested, for the rill heights of 15 m, 20 m, 25 m and 30 m. The study concluded that the arches assisted in reducing the ground convergence in the production drift. The results also showed that the total height of the rill bench yields regardless of its height. After the yielding, the rockmass can no longer support itself and caves under its own weight. The larger the rill height, the larger the volume of loose rock that has to be supported and thus, higher the convergence. Furthermore, it was also observed that, significant amount of convergence in the production drift occurred during the drifting of the top drive and less during the stoping of the rill bench. This indicates that, the timely installation of the arches is an important criterion for their performance.

Most masonry arch structures behave as complex 3-dimensional structures. For the convenience of the analyst such structures are usually modelled as 2-dimensional structures with the effects of their 3-dimensional characteristics being taken into account by modifying the arch parameters and the output of the analysis. The thesis outlines a research programme which fundamentally attempts to model the 3-dimensional nature of 'real' arches. An experimental programme comprising tests on skew multi-ring brickwork arch ribs and point loading of a multi-ring brickwork square span arch with an aspect ratio of 1.25 is used to validate the modelling. The thesis will present the results from the laboratory tests. Class 'A' engineering bricks with 1:2:9 lime mortar were used to construct the two ring arch ribs. A skew angle of 45 was adopted with a square span between the interfaces of the supports of 3 metres. The square span to rise ratio was 4. The ribs were approximately 670 wide. Headers were provided to prevent ring-separations and the English method of skew arch constructions was used which resulted in the mortar bedding planes being square to the elevation at the crown and inclined to the abutments at the springings. Three-dimensional macro-models are used to simulate both the large-scale square arch tests and the two skew arch tests. The results of each of the FE analyses are compared with data obtained from the corresponding experiments. Reasonable agreement between FE analyses and experimental results has been obtained. The values and applicability of the research in engineering practice have been demonstrated.

The objective of the research programme has been to investigate the problems besetting the national masonry arch bridge stock and topropose enhanced means of appraisal accordingly. The programme has involved site assessments and limited experimentation together with limit state and serviceability analyses. All theoretical and empirical studies have been mounted as micro-computer software and are supported by computer graphics. Throughout, the accent is on engineering requirements in practice; the almost universal absence of as-built drawings and the involvement of natural materials whose mechanical properties are highly variable are to be noted from the outset. Initial considerations relating to the arch form, its historical context and present masonry arch assessment methods are set out in Chapter 1. Fieldwork studies are presented in Chapter 2. The concept that masonry has finite compressive strength isaccordingly considered in Chapter 3 which includes experimentation establishing the appropriate constitutive properties with respect to natural rock. A general moment-thrust response modelling is established and an original non-linear limit-state moment-thrust interaction diagram is determined. Limit state and serviceability masonry arch bridge models ofinnovatory form are included in Chapter 4. These models follow from the studies of Chapter 3 and are novel in their own right. However, the critical arguments upon which they are based demand that these models be seen as prototypes of enhanced models whose features have now been established. Overall conclusions are discussed in Chapter 5 wherein the practical factors affecting the nature of masonry arch bridges are juxtaposed with the engineering requirements imposed upon them. Modern assessment methods must afford output that is safe without being overconservative. The findings of the research programme are in keeping with this. Supporting documentation is given in the Appendices.

In this study, a laminated glass unit which consists of two glass sheets bonded together by PVB is analyzed as a curved beam and as a cylindrical shell. Laminated glass curved beams and shells are used in architecture, aerospace, automobile and aircraft industries. Curved beam and shell structures differ from straight structures because of their initial curvature. Because of mathematical complexity most of the studies are about linear behavior rather than nonlinear behavior of curved beam and shell units. Therefore it is necessary to develop a mathematical model considering large deflection theory to analyze the behavior of curved beams and shells. Mechanical behavior of laminated glass structures are complicated because they can easily perform large displacement since they are very thin and the materials with the elastic modulus have order difference. To be more precise modulus of elasticity of glass is about 7*104 times greater than the modulus of elasticity of PVB interlayer. Because of the nonlinearity, analysis of the laminated glass has to be performed by considering large deflection effects. The mathematical model is developed for curved beams and shells by applying both the variational and the minimum potential energy principles to obtain nonlinear governing differential equations. The iterative technique is employed to obtain the deflections. Computer programs are developed to analyze the behavior of cylindrical shell and curved beam. For the verification of the results obtained from the developed model, the results from finite element models and experiments are used. Results used for verification of the model and the explanation of the bahavior of the laminated glass curved beams and shells are presented in figures.

There are over 40,000 road bridges in the UK and most of them are over a hundred years old. These bridges were not designed to carry today's modern traffic and the everincreasing live loads especially with the introduction of 40 tonne lorries since January 1999. Moreover, in the case of multi-ring brickwork arches the penetration of rainwater and/or overloading with the passage of time breaks the adhesion between the rings leading to ring separation. The loss of continuum behaviour is accompanied by a significant drop in load carrying capacity. It is important that they continue to perform their functions. Sympathetic strengthening is preferred to demolition and replacement. A large amount of work has, in recent years, been devoted to the study of the behaviour of brickwork arch bridges subjected to monotonic loading. However, little is known about the behaviour under cyclic loading. The thesis reports the results of tests under cyclic loading applied at the quarter spans on six large-scale brickwork arch bridges of spans 3m and 5m. Some of them were constructed with damp sand between the brickwork rings, which simulate the defect of ring separation in real bridges. The tests were used to develop a better understanding about the behaviour and failure mechanisms of these arches subjected to cyclic loading. Additionally, the efficacy of surface strengthening to the structural performance of multi-ring brickwork arches was investigated. Both the ring separation and surface strengthening affects the behaviour of arches subjected to cyclic loading where the former reduces the carrying capacity and the latter increases the carrying capacity. The static failure loads of brickwork arches were predicted using four different methods: the mechanism method, Gilbert's 'RING' program, the elastic method and the FE method using ABAQUS software. It was found that the mechanism method and the 'RING' program were conservative in predicting the carrying capacity of the tested arches.

This thesis presents the nonlinear in-plane behaviour of circular fixed arches subjected to thermal loading only. Due to the nonlinear prebuckling behaviour of arches and its effects, classical buckling theory which is founded on geometric prebuckling linearity can not predict the in-plane buckling of arches accurately. Based on a nonlinear formulation of the strain and displacement relationship and considering constant thermal distributions only, virtual work formulations are used to establish the differential equations of in-plane equilibrium and the statical boundary conditions, from which the nonlinear equilibrium equations are derived in closed form and which are suitable to use in design. By considering the adjacent buckled configurations, the differential buckling equilibrium equations are formulated from the principle of virtual work as well, and the analytical solutions for the nonlinear buckling of fixed arches are obtained. It is shown that nonlinear elastic buckling of a fixed in the plane of it curvature can not occur when it is subjected to thermal loading only, except if the arch is as a straight column. By using the algebraic representation of nonlinear in-plane equilibrium derived in this thesis, the elastic response of fixed arches at elevated temperatures and the attainment of first yield are examined in detail. The arch deflects transversely without bound in the elastic range at elevated temperatures, whereas it will yield first at the top extreme fibre of the cross section at the supports when a critical temperature is reached. The influence of several parameters such as the included angle is also considered. Based on the models of stress distributions at cross sections, the spread of yield both through the cross section and along the length of the arch is studied. It is indicated that the progress of yielding causes the first two hinges to form at the supports of the fixed arches, and then moment redistribution leads to the generation of the third hinge at the crown with an increase of temperature. Thus nonlinear plastic hinge analysis can be applied to the arch analysis under thermal loading.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Arcos abatidos são usados com frequência para vencer grandes vãos. Exemplos incluem pontes em arco e coberturas de grandes espaços como galpões industriais e estádios. Em muitos casos empregam-se arcos atirantados ou apoiados em estruturas flexíveis, fazendo com que os apoios se movam quando o arco é carregado. Isto aumenta a flexibilidade do sistema e a probabilidade de perda de estabilidade na presença de cargas estáticas e dinâmicas. Em muitos casos estas estruturas podem ser modeladas como arcos com apoios elásticos. No presente trabalho resolve-se o problema de estabilidade estática de forma analítica e através de uma aproximação usando o método de Ritz, servindo a solução analítica para aferir a precisão do modelo numérico. A seguir, com base neste estudo, desenvolve-se, usando o método de Ritz, a formulação para análise das vibrações não lineares do arco com apoios elásticos, assunto inédito na literatura. Os resultados mostram a grande influência dos apoios nas vibrações não lineares e na estabilidade do arco sob cargas estáticas e dinâmicas.
Shallow arches are often used to overcome large spans, for example, arch bridges or steel roofs to cover large spaces such as industrial sheds and stadiums. In many cases the arches are tied or are supported by a flexibility structure, causing that supports to move when the arch has been loaded. This increases the flexibility of the system and the probability of loss of stability in the presence of static and dynamic loads. In many cases, these structures can be modeled as arches with elastic supports. In the present work the static stability has been solved analytically and through the Ritz method, serving the analytical solution to assess the accuracy of the numerical model. Then, based on this study, the analysis of nonlinear vibrations of shallow arches with elastic supports is developed, using the Ritz method, a subject not yet studied in the literature. The results show the noticeable influence of the supports on the nonlinear vibration and stability of shallow arches under static and dynamic loads.

The purpose of this master’s thesis was to investigate if suspension of heavy objectsis possible in the glulam arches at Stockholm Central Station. The main goal was todetermine the arches’ load carrying capacity’s utility ratio, in order to give knowledgeif additional loading can be added.The study included a thorough investigation of available blueprints and calculationreports established during and after the process of design and erection of the arches.In addition, an on-site-inventory was made to confirm and verify the studied material.A method to approximate semi-probabilistic material strength-properties, based onold deterministic material strength properties, was used.When the material had been summarized concluding geometrical attributes, loads, andmaterial properties a calculation model of the arch was developed. The global geometrydescribing the arch’s shape mathematically was established through measures onblueprints and analytical calculations in Mathcad. A finite element method (FEM) wasthen used to calculate reaction- and internal forces and buckling modes taking accountfor 2nd order effects. Once calculation of intrenal forces had been made, the structuralcapacity was checked analytically according to Eurocode’s failure criterion.The results showed that the arches do not fulfill required carrying capacity forEurocode’s symmetric- and non-symmetric distributed snow load. The failurecriterion not fulfilled were simultaneously bending and compression, lateral torsionalbuckling and simultaneously tension perpendicular to grain and shear.It is therefore concluded that suspension of heavy objects is not suitable with thepresent condition of the arch. In order to realize suspension, it is suggested thatreinforcement measures have to be conducted. It is also suggested that shear andiiiflexural carbon fiber reinforced polymer (CFRP) reinforcement would be a suitablemethod of enhancing the strength and stiffness of the arches, without disrupting theiraesthetics and integrity.

In recent years, leaning arches have been used in frameworks for some tent structures. Various people have studied the behavior of a single vertical arch; however, only a few researchers have considered the three-dimensional behavior of arches and leaning arches. The objective of this thesis is to analyze the three-dimensional nonlinear behavior of leaning arches, particularly the load-deflection and load-frequency relationships, and to provide a basis for future design guidelines. In this study, vertical arches of different shapes and load combinations are analyzed in order to compare with previous results given by other researchers. Then, the behavior of single tilted arches with different tilt angles is considered. Finally, a leaning arch structure, with two arches inclined to each other and joined at the top, is considered. The load displacement and load-frequency relationships, as well as some buckling modes, are discussed and presented in both tabular and graphical formats.
Master of Science

This thesis sets out to explore the implications that transport infrastructures have on the production and perception of the urban built environment. Particularly, it focuses on the Victorian brick viaducts constructed to support the elevated railway in Manchester, England. It concentrates on Manchester’s post-industrial restructuring and re-imaging since the late 1960s, exploring how the presence of brick railway viaducts, as well as the uses beneath their arches, have impacted strategies for revalorisation in the wake of gradual deindustrialisation. In exploring the changing symbolic economy of landscapes dominated by railway infrastructure, as well as the shifting uses and images of railway arches, this thesis explores the interplay between political economy and the aesthetic and symbolic dimensions of urban regeneration. Upon establishing the mutually constituted history of Manchester’s elevated railways and its city centre and demonstrating how this 19th century process has shaped the form and character of the city, it excavates a cultural history of the infrastructural landscapes of the city. Special emphasis is placed on the uses and perceptions of railway arches, which have long served as symbols of dereliction and social disorder. These spatial and cultural histories act as a foundation for analysing how the city’s railway viaducts have been implicated in the re-imagining of Manchester as a post-industrial city. These histories and representations are explored in relation to property-led strategies of environmental improvement, industrial displacement, and heritage tourism along the southern fringe of Manchester city centre, focusing on three thematic and spatially bound case studies. These case studies rely on documentary data of planning and design strategies, interviews with elite actors involved in the re-imaging of Manchester city centre, and ethnographic observation. Using critical discourse analysis, the thesis unpacks the narrative relationship between dominant representations of these spaces and professional justifications for their material and symbolic reconfiguration.

The main purpose of this thesis is to critically analyse the convergence of political Islam and neoliberalism in Turkey. By doing so, the research aims to construct a Gramscian historical materialist account as opposed to the mainstream centre-periphery relations approach. The mainstream centre-periphery relations approach takes the state and civil society as antagonistic autonomous entities. This consideration brings us where the Turkish politics are perceived as a terrain of conflict between Islamists and secularists. The centre-periphery relations approach has four shortcomings. First, the state and society are considered separately. Second, the market and the state; and the economy and the politics are considered separately. Third, as considered separately, the theory takes civil society as automatically progressive. Fourth, the social relations of productions are neglected. This thesis argues that the Islamists versus secularists dichotomy is not sufficient enough to explain the complexity of contradictions in Turkish politics because of the given four shortcomings. Therefore, a more complex theory where the antagonism is considered within the class struggle is needed. Antonio Gramsci’s theory of hegemony, passive revolution and most importantly the integral state provides a new window in this respect. The Gramscian historical materialism offers a holistic understanding for the relationship between the state and society, the market and the state, and the economy and the political. As part of the hegemonic struggle, civil society can be on either side of the struggle therefore it is not considered as automatically progressive in Gramscian historical materialism. As a historical materialist approach, Gramscianism considers the social relations of production as the crucial element of the analysis. The pre-2002 periods (before the Justice and Development Party came into power) were already researched by Gramscian scholars. Therefore, the neoliberal restructuring in Turkey during the Justice and Development Party era is the focal period of this thesis. There will be a specific focus on the cases of urbanisation, education, and the mass media. The conceptual framework of state-society relations is the analytical basis of this study. Overall, this thesis offers an alternative reading of the rise of political Islam in Turkey.

In the last two decades, FRP (Fibre-Reinforced Polymers) composite materials have been adopted for strengthening and repair of both modern and historic masonry constructions (buildings, bridges, towers) and structural components (walls, arches and vaults, piers and columns). Strengthening of masonry brick arches and vaults with FRP laminates can contribute significantly in the improvement of their structural capacity at a limit state, by activating local mechanisms both at material and interface levels, but also modifies the collapse mechanisms of the original structures, as the reinforcement prevents the typical brittle failure due to the formation of hinge-mechanisms. Despite the increasing number of specific studies on FRP reinforcement of masonry structures, investigations are still limited if compared to reinforced concrete applications. Moreover, few codes and recommendations are currently available. Starting from these points, the present work deals with experimental investigations on three local mechanisms involved by the collapse of FRP-reinforced masonry arches: the interface behaviour in the case of stresses normal to the surface (FRP detachment observed in structures with intrados reinforcement) has been investigated through the execution of a large number of combined tests on solid clay bricks (flexural, compressive, splitting and pull-off tests) aimed at experimentally calibrate possible correlations among the corresponding strength parameters and to observed possible influences of the fibres type and the presence of primer on the pull-off behaviour; the bond behaviour has been investigated by performing ten Double-lap Shear Tests on solid clay bricks, aimed at calibrating fracture energy value and bond-slip law for both carbon FRP and glass FRP reinforcement (moreover, a simple exponential-based bond-slip law has been proposed); the mixed-mode behaviour (fourteen tested samples) has been investigated by adapting a test setup developed for FRP applications on reinforced concrete, known as V-shape Peel Test, to clay substrate, in order to reproduce on a local scale the conditions related to the shear sliding failure of arches with extrados reinforcement. Finally, several case studies, concerning real-scale or scaled brick masonry arches and vaults reinforced at their intrados or extrados, have been collected from literature in order to compare the experimental results to the available interpretative models of the global behaviour of the structure at failure.
Negli ultimi due decenni, i materiali compositi FRP (Fibre-Reinforced Polymers) sono stati adottati anche nel rinforzo di costruzioni murarie sia moderne sia antiche (edifici, ponti, torri), nonché di vari elementi strutturali (pareti, archi e volte, pile e colonne). Il rinforzo di archi e volte in muratura con FRP può contribuire in modo significativo a migliorare la loro portanza in stato limite, attivando meccanismi locali a livello di materiali e interfaccia, ma comporta anche un cambiamento dei meccanismi di collasso della struttura originale, dal momento che il rinforzo impedisce la tipica rottura fragile causata dalla formazione di meccanismi a cerniera. Nonostante un crescente numero di studi riguardanti il rinforzo di strutture murarie con FRP, le indagini sono tuttavia ancora limitate, se confrontate con applicazioni su calcestruzzo armato. Inoltre, pochi codici e raccomandazioni sono attualmente disponibili. Partendo da questi punti, il presente lavoro affronta l'indagine sperimentale di tre meccanismi locali coinvolti nel collasso di archi rinforzati con FRP: il comportamento dell’interfaccia nel caso di tensioni normali alla superficie (distacco del composito osservato in strutture rinforzate all’intradosso) è stato investigato mediante l’esecuzione di un ampio numero di prove combinate eseguite su mattoni pieni in laterizio (prove a flessione, compressione, trazione indiretta e pull-off), allo scopo di calibrare sperimentalmente eventuali correlazioni fra i relativi parametri di resistenza e di osservare eventuali influenze del tipo di fibra e della presenza del primer sul comportamento nella prova di pull-off; il comportamento nel caso di azioni tangenziali è stato studiato mediante l’esecuzione di dieci Double-lap Shear Tests su mattoni pieni in laterizio, al fine di calibrare energia di frattura e legge bond-slip per rinforzo in fibra di carbonio e fibra di vetro (inoltre, è stata proposta una semplice legge bond-slip); il comportamento nel caso di azioni miste (quattordici prove eseguite) è stato investigato mediante l’adattamento di una prova sviluppata per applicazioni di FRP su calcestruzzo armato, nota come V-shape Peel Test, a mattoni in laterizio usati come substrato, allo scopo di riprodurre a scala locale le condizioni relative allo scorrimento a taglio sul giunto di archi con rinforzo estradossale. Infine, vari casi studio, riguardanti archi e volte in muratura, a dimensioni reali oppure scalate, sono stati raccolti da letteratura al fine di comparare i risultati sperimentali con i modelli interpretativi del comportamento globale della struttura a collasso attualmente disponibili.

L'interaction entre des lignes de contact et un écoulement hydrodynamique intervient dans de nombreuses situations industrielles ou fondamentales. Nous étudions la dynamique de gouttes ruisselantes, tout d'abord le long de leur axe de symétrie (Partie I) puis à trois dimensions (Partie II) en mesurant la distribution d'angle de contact autour de cette goutte par réfraction d'une nappe laser et le champ de vitesse à la surface. Nous montrons que la situation est localement à deux dimensions, dans la direction perpendiculaire à la ligne de contact. L'angle de contact ne dépend que de la vitesse de la ligne de contact mesurée perpendiculairement à elle-même, vitesse qui coïncide avec la vitesse locale du liquide, dont la composante tangentielle s'annule à la ligne de contact. Dans le cas de lignes singulières (en coin), ou deux normales coexistent en un point, nous montrons que le champ de vitesse est autosimilaire à l'approche de ce point, Nous abordons également (Partie III) la question des lignes de contact statiques dans un écoulement à travers l'étude de la stabilité et de la forme de zones sèches dans un film liquide en écoulement. Nous montrons en particulier l'influence du mouillage sur ces objets et nous mesurons l'angle de contact tout autour de ces zones sèches. Nous montrons que la distribution d'angle de contact est, suivant l'histoire de la zone sèche, uniforme et bloquée à l'angle d'avancée (ce qui permet de construire des modèles simples) ou au contraire relativement désordonnée, Enfin nous mettons en évidence un phénomène encore non reconnu de stick-slip de la ligne de contact lorsqu'une goutte de suspension colloïdale en cours de séchage avance (interaction entre dépôt et hydrodynamique).

L'interaction entre des lignes de contact et un écoulement hydrodynamique intervient dans de nombreuses situations industrielles ou fondamentales. Nous etudions la dynamique de gouttes ruisselantes, tout d'abord le long de leur axe de symétrie (Partie I) puis a trois dimensions (Partie II) en mesurant la distribution d'angle de contact autour de cette goutte par réfraction d'une nappe laser et le champ de vitesse a la surface. Nous montrons que la situation est localement à deux dimensions, dans la direction perpendiculaire à la ligne de contact. L'angle de contact ne dépend que de la vitesse de la ligne de contact mesurée perpendiculairement a elle-même, vitesse qui coïncide avec la vitesse locale du liquide, dont la composante tangentielle s'annule a la ligne de contact. Dans le cas de lignes singulières (en coin), ou deux normales coexistent en un point, nous montrons que le champ de vitesse est autosimilaire a l'approche de ce point. Nous abordons également (Partie III) la question des lignes de contact statiques dans un ecoulement à travers l' etude de la stabilité et de la forme de zones sèches dans un film liquide en écoulement. Nous montrons en particulier l'influence du mouillage sur ces objets et nous mesurons l'angle de contact tout autour de ces zones sèches. Nous montrons que la distribution d'angle de contact est, suivant l'histoire de la zone sèche, uniforme et bloquée a l'angle d'avancée (ce qui permet de construire des modèles simples) ou au contraire relativement désordonnée. Enfin nous mettons en évidence un phénomène encore non reconnu de stick-slip de la ligne de contact lorsqu'une goutte de suspension colloïdale en cours de séchage avance (interaction entre dépôt et hydrodynamique).

The vertebrate Dlx homeodomain-containing genes are generally organized as three convergently transcribed bigene clusters. Paired genes share highly conserved overlapping expression patterns in the forebrain, the pharyngeal arches, sensory placodes and limb/fin buds. Little is known about how the Dlx genes are targeted to their sites of expression, or what particular roles individual genes play in development. In the pharyngeal arches, Dlx genes are expressed in a nested manner, which defines proximodistal identity. We identified two distinct cis-acting enhancers, I12a and I56i situated between Dlx1/2 and Dlx5/6 pairs respectively that regulate expression in the mandibular arch. In transgenic animals, the two enhancers targeted reporter gene expression to distinct populations of mesenchymal cells in the mandibular arch. Both enhancers responded to epithelial signaling cues, such as FGF8 and BMP4, similar to endogenous Dlx genes. Therefore, the combinatorial arch expression is achieved through interaction between signaling factors and intrinsic cellular factors. To investigate the individual roles of the paired Dlx1/2 gene in patterning the pharyngeal arches, we silenced zebrafish dlx1a and dlx2a using morpholino antisense oligonucleotides. Loss of dlx2a function in zebrafish embryos resulted in reductions of arch neural crest markers as well as perturbation of neurogenic and chondrogenic derivatives. Loss of dlx1a resulted in malformations of cartilage elements indicating a role in arch patterning. To explore further the evolution of the Dlx gene family, we characterized the Distal-less homologue, Odidll, in the protochordate species, Oikopleura dioica. Odidll is not part of a bigene cluster suggesting either that a paralogue was lost or that the tandem duplication event occurred subsequent to the species' divergence. Odidll, was expressed in ectodermally-derived tissues suggesting a role that may have been observed in a common chordate ancestor. These results contribute to our understanding of Dlx regulation, function and evolution.

This thesis largely explores ways in which American Indian views of time and space are expressed, with a specific focus on the concept of a portal. Traditional worldviews held by many American Indian groups translate time and space as nonlinear and nonexclusive; multiple spatial and temporal dimensions can exist simultaneously. Here, a physical medium that facilitates movement among the multiple, intangible dimensions, i.e., portal, is needed in order for the dimensions to be visited and thus be perceived as real. In many American Indian worldviews, the power of portal is often concentrated in certain natural and cultural components such as arches, alcoves, caves, and peckings and paintings on rock surfaces. In discussing the concept of portals, this thesis suggests two distinct landscapes as case studies: arches within Arches National Park (Arches NP) and an alcove with prominent rock paintings near Canyonlands National Park (Canyonlands NP). Discussion of these two case studies and their significance as portals help us to understand American Indian ways of perceiving landscapes and American Indian worldviews concerning time, space, as well as spirits. Eventually, this thesis aims to situate the two case studies within the wider discourse of portals that connect multiple temporal and spatial, and mundane and spiritual dimensions.

This thesis applies Nicolas Bourriaud’s concept of ‘relational aesthetics’ to the development of site-specific theatre practice. Focussing on the Arches arts centre in Glasgow, the aim is to suggest ways in which a performance aesthetic can be developed that uses, makes evident and contributes to what Bourriaud describes as the ‘space of relations’ that exists within every site. Employing a practice-as-research methodology in order to develop a ‘relational theatre practice’, the performances that comprise half of this thesis aim to respond to and generate relationships not only between theatre and its ‘audience’, but through a sensitivity to site as historically, geographically, culturally and socially located. Key to this project is an understanding of the boundaries, limitations and exclusions that inevitably come to define theatre practice in a site with as many contradictory and conflicting relationships as a busy arts venue like the Arches. The findings of this research are primarily dependent on three practice-as-research projects at the venue: Underneath the Arches (January 2009), Midland Street (September 2009) and A Work on Progress (April 2010). These projects have focussed respectively on three key areas of relational theatre practice; the performance text, the theatre audience and processes of theatre production. The written part of the thesis provides an exegesis of this practice, critically reflecting on the relationships that developed through the performances. Combining a practical and theoretical approach, this research interrogates Bourriaud’s relational aesthetic model through its application to the development of theatre practice within the specific context of a cultural site. Conversely, it reveals and works with the multiple relationships of the Arches, thereby providing new knowledge about the relational processes through which a cultural site is constituted.

[ES] Hoy en día, la arquitectura moderna está orientada principalmente al empleo eficiente de materiales tecnológicos y sostenibles, la tecnificación del proceso de diseño, proyecto y construcción, y la búsqueda de soluciones muy ligeras. Estas ideas se reflejan en las estructuras flexo-activas, que recientemente han atraído considerable atención como nuevo paradigma para construir estructuras ligeras, tanto en el ámbito de la investigación como en la práctica. El término "flexión activa" hace referencia a una categoría de estructuras en las que la flexión se emplea en el proceso de configuración de su forma. Los sistemas estructurales flexo-activos incluyen barras o láminas incurvadas cuya geometría es el resultado de su deformación elástica desde una configuración inicial recta o plana. Hasta el momento, el número de realizaciones es limitado; se trata sobre todo de aplicaciones experimentales con funcionalidad arquitectónica o artística. La obtención de la configuración de equilibrio es una de las principales dificultades que aparecen en la fase de concepción, debido precisamente a la no linealidad de la respuesta estructural de las barras activas, así como a la posible interacción con otros elementos estructurales como membranas o cables, que trabajan por forma, y cuya geometría no se puede fijar de modo arbitrario. Los métodos computaciones de determinación de forma para estructuras flexo-activas incluyen modelos de elementos finitos con cables virtuales no lineales que se acortan hasta alcanzar la configuración final, o algoritmos de relajación dinámica que consideran las variables que caracterizan la deformación de las barras activas. Esta tesis doctoral tiene por objeto proporcionar un análisis en profundidad de la aplicabilidad del principio de flexión activa al diseño de estructuras ligeras, en particular a los puentes peatonales. Para ello, la investigación se aborda desde tres puntos de vista: a) modelización computacional; b) eficiencia estructural; c) diseño y construcción. En primer lugar, se lleva a cabo una revisión de la bibliografía existente, haciendo hincapié en los trabajos previos en el diseño de pasarelas con flexión activa. En el campo de la modelización computacional, se desarrolla un novedoso método numérico de determinación de forma para estructuras flexo-activas basado en el modelo geométricamente exacto para piezas alargadas (también conocido como la teoría de vigas de Reissner-Simó). Distintos ejemplos numéricos han sido reproducidos para mostrar la exactitud del método. La parte de la investigación relacionada con el análisis de la eficiencia estructural se centra en el comportamiento del sistema flexo-activo propuesto en esta tesis para el diseño de estructuras ligeras: el arco flexo-activo arriostrado (o atirantado). Se trata de un arco plano compuesto por una barra flexible y continuo que se activa por la acción de los cables principales que tiran de ambos extremos de la varilla, y de los puntales o cables secundarios que desvían el cable principal y actúan en ciertas secciones transversales. La parte computacional-analítica se completa con el desarrollo de un procedimiento numérico basado en algoritmos genéticos, con el fin de obtener configuraciones estructurales eficientes. La tesis finaliza con el diseño, fabricación y montaje de una pasarela flexo-activa hecha con tubos PRFV utilizando este tipo estructural, realizada en el laboratorio de modelos de la Universitat Politècnica de València.
[CA] Hui dia, l'arquitectura moderna està orientada principalment a l'ús eficient de materials tecnològics i sostenibles, la tecnificació del procés de disseny, projecte i construcció, i la cerca de solucions molt lleugeres. Aquestes idees es reflecteixen en les estructures flexo-actives, que recentment han atret considerable atenció com a nou paradigma per a construir estructures lleugeres, tant en l'àmbit de la investigació com en la pràctica. El terme "flexió activa" fa referència a una categoria d'estructures en les quals la flexió s'empra en el procés de configuració de la seua forma. Els sistemes estructurals flexo-actius inclouen barres o làmines incorbades, la geometria de les quals és el resultat de la seua deformació elàstica des d'una configuració inicial recta o plana. Fins al moment, el nombre de realitzacions és limitat; es tracta sobretot d'aplicacions experimentals amb funcionalitat arquitectònica o artística. L'obtenció de la configuració d'equilibri és una de les principals dificultats que apareixen en la fase de concepció, degut precisament a la no linealitat de la resposta estructural de les barres actives, així com a la possible interacció amb altres elements estructurals com a membranes o cables, que treballen per forma, i la geometria de la qual no es pot fixar de manera arbitrària. Els mètodes computacions de determinació de forma per a estructures flexo-actives inclouen models d'elements finits amb cables virtuals no lineals que s'escurcen fins a aconseguir la configuració final, o algorismes de relaxació dinàmica que consideren les variables que caracteritzen la deformació de les barres actives. Aquesta tesi doctoral té per objecte proporcionar una anàlisi en profunditat de l'aplicabilitat del principi de flexió activa al disseny d'estructures lleugeres, en particular als ponts per als vianants. Per a això, la investigació s'aborda des de tres punts de vista: a) modelització computacional; b) eficiència estructural; c) disseny i construcció. En primer lloc, es duu a terme una revisió de la bibliografia existent, amb recalcament en els treballs previs en el disseny de passarel·les amb flexió activa. En el camp de la modelització computacional, es desenvolupa un nou mètode numèric de determinació de forma per a estructures flexo-actives basat en el model geomètricament exacte per a peces allargades (també conegut com la teoria de bigues de Reissner-Simó). Diferents exemples numèrics han sigut reproduïts per a mostrar l'exactitud del mètode. La part de la investigació relacionada amb l'anàlisi de l'eficiència estructural se centra en el comportament del sistema flexo-actiu proposat en aquesta tesi doctoral per al disseny d'estructures lleugeres: l' arc flexo-actiu esbiaixat (o lligat). Es tracta d'un arc pla compost per un membre flexible i continu que s'activa per l'acció dels cables principals que tiren de tots dos extrems de la vareta, i dels puntals o cables secundaris que desvien el cable principal i actuen en certa secció transversal de la vareta. La part computacional-analítica es completa amb el desenvolupament d'un procediment numèric basat en algorismes de tipus genètic, amb la finalitat d'obtindre configuracions estructurals eficients. La tesi finalitza amb el disseny, fabricació i muntatge d'una passarel·la flexo-activa feta amb tubs PRFV utilitzant aquest tipus estructural, realitzada en el laboratori de models de la Universitat Politècnica de València.
[EN] Nowadays, modern architecture is focused on the search of efficient uses of technological and sustainable materials, high-tech concept-design-erection processes and the possibility to produce lightweight solutions with maximum elegance in shape. These ideas are reflected on bending-active structures, which recently attracted considerable attention as a new paradigm to build lightweight structures both in research and practice. The concept 'active bending' refers to a category of structures in which bending is used in the process of shape configuration. Bending-active structural systems include curved rods or shells which have been elastically bent from an initial straight or plane configuration. As of now, the number of realisations is limited; they are mostly experimental ones, with architectural or artistic nature. Form finding of the equilibrium configuration is one of the main difficulties during the conceptual phase, due to the non-linearity of the structural response of the active members, and also to the interaction with other form-active structural elements as membranes or cables, whose geometry cannot be prescribed in advance. Computational form-finding methods for bending-active structures include finite element models with non-linear virtual links that are shortened to reach the final form, or dynamic relaxation (explicit) algorithms to cope with the variables describing the response of the active members. This PhD thesis aims to provide an indepth analysis on the applicability of the active bending principle to the design of lightweight structures, in particular pedestrian bridges. For that purpose, the work is carried out from three points of view: (a) computational modelling and simulation; (b) structural performance and efficiency; (c) design and construction. First of all, a literature review on the topic and a overview of realisations in the fied of bending-active footbridges is provided. In the field of computational modelling, a novel form-finding method based on the geometrically exact rod model (or Reissner-Simo beam theory) is implemented. Numerical examples are also given to show the accuracy of the method. The part of the work related to the analysis of the structural performance and efficiency is focused on the bending-active configuration proposed in this PhD thesis for designing lightweight structures: the bending-active braced (or tied) arch. This is a simple planar arch composed of a continuous flexible member that is activated by the action of main cables pulling at both ends of the rod, and secondary struts or cables that deviate the main cable and act at certain cross-section of the rod. The computational-analytical part is completed with the development of a numerical procedure based on genetic algorithms to obtain efficient structural configurations. The thesis ends with the design, fabrication and assembling of a bending-active short footbridge made of GFRP tubes using this structural type, held in the laboratory of concept models of the Polytechnic University of Valencia.
The author has had the opportunity to join the research project: Sistemas estructuras flexo-activos- Concepción, desarrollo y análisis de nuevos prototipos (FLEXACT - grant BIA2105-69330- P)
Bessini Muñoz, JG. (2021). Form-finding and Performance of Bending-active Structures. Proposals of Application to Lightweight Braced Arches [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/165575
TESIS

Resumo: O objetivo deste trabalho foi medir médias para algumas medidas intra e interarcos em modelos de gesso da população brasileira branca portadora de oclusão normal. Para isso, 51 modelos de oclusão normal foram digitalizados tridimensionalmente com o Microscribe duas vezes com um espaço de sete dias entre as digitações para avaliação do erro do método. Os dados conseguidos foram então trabalhados através do programa Tigaro. A estatística para estimar-se as médias foi realizada através da análise de modelo multinível e os erros sistemático e casual foram calculados através dos teste T- student e pela fórmula de Dahlberg, respectivamente. Como resultado foram estabelecidas estimativas das médias para a população brasileira com oclusão normal das distâncias intercaninos, intermolares, inter 1os pré-molares e inter 2os pré-molares, comprimento de arco, torques e inclinações dentárias, espessuras dos dentes no terço médio, altura de cúspides, profundidade da curva de Spee, overjet e overbite, angulação entre os planos oclusais, desvio de linha média e as diferenças entre as bordas oclusais dos dentes anteriores. Também a partir deste estudo, determinou-se um formato de arco padrão para a amostra estudada, que pode ser utilizado como template para arcos em ortodontia... (Resumo completo, clicar acesso eletrônico abaixo).
Abstract: The aim of this paper was to measure the average of some intra and interarches measurements in cast models of the white brazilian population with normal occlusion. In order to achieve this objective, 51 models were digitized threedimensionally with a Microscribe twice seven days apart for method error evaluation. The collected data was then worked on the software Tigaro. The statistics used was the multilevel models analysis in order to estimated the means for the measures and the systematic and random error were calculated through the t-student test and Dahlberg's formula, respectively. As a result estimated means of intercanine, intermolar and interpremolar widths, arch length, torques and inclinations, teeth mid-third widths, cusp height, deepness of the curve of Spee, overjet and overbite, angulation between the planes of occlusion, mid-line deviation and the differences of the heights of the incisal borders of the anterior teeth were established for the white brazilian population with normal occlusion. Also, through this study a pattern of arch form was established for the sample studied, that can be used as a template for orthodontic arches.
Orientador: Luiz Gonzaga Gandini Júnior
Coorientador: Haruaki Hayasaki
Banca: Ary dos Santos Pinto
Banca: Adriano Marotta Araújo
Mestre

This thesis explores the possibilities of using varied long span glue-laminated arches to create a dynamic structural enclosure over an expansive open surface. It investigates using arches that increase and decrease in height and span width, while varying in their lean. When combined with a fabric enclosure, they create a roof that constantly changes. The idea is to create a world class equestrian center that is visually exciting from both the interior and exterior, rather than simply creating a large scale version of a barn.
Master of Architecture

Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, December 1990.
Thesis Advisor(s): Salinas, David. "December 1990." Description based on title screen as viewed on April 1, 2010. DTIC Identifier(s): Arches, Stress Analysis, Weight, Finite Element Analysis, Computer Programs, Optimization, Theses, Degrees Of Freedom, FORTRAN, Stiffness, Case Studies. Author(s) subject terms: Finite Element Method, Arches, Weight Optimization. Includes bibliographical references (p. 107). Also available in print.

Le développement cranio-facial est un processus complexe qui implique interactions tissulaires et différenciations cellulaires. La façon dont ces processus sont coordonnés lors de l'embryogenèse reste évasive. Perturber ce développement coordonné provoque un large éventail de malformations. Afin de trouver de nouveaux gènes impliqués dans le développement de la tête, un criblage phénotypique a été réalisé par mutagenèse. L'une des lignées de souris obtenues montre des malformations au niveau des arches pharyngées (AP), qui sont les précurseurs de la tête. Ces mutants meurent à mi gestation, due à des problèmes vasculaires. La mutation ponctuelle générée a été localisé dans le gène Mortalin. Mon travail de thèse vise à comprendre comment Mortalin contrôle le développement embryonnaire. Mortalin est exprimée de manière ubiquitaire, puis son expression augmente au niveau des AP, dans les tissus musculaires et nerveux. Pour déterminer les mécanismes moléculaires affectées chez ce mutant, un profil d'expression génique a révélé l'induction de gènes impliqués dans la réponse au stress du réticulum endoplasmique (RE), appelée UPR, dont le rôle est de rétablir l'homéostasie du RE. Mortalin est impliqué dans le contrôle de l'UPR en interagissant avec BiP, un régulateur direct de cette voie. L'activation soutenue de l'UPR entraîne l'apoptose, ce que nous observons chez nos mutants. De plus, l'analyse du cycle cellulaire indique que la phase S est plus longue chez le mutant, suggérant que Mortalin régule le cycle cellulaire. Ainsi, l'ensemble des données suggère que Mortalin est nécessaire pour la survie des cellules au cours du développement
The development of the head is a complex process that involves tissue interaction and cellular differentiation. Precisely how these processes are coordinated during embryogenesis remains elusive. Disruption of this coordinated development causes a wide range of malformations. In order to find new genes involved in the development of the head, a phenotype-driven ENU screen was performed. One of the mouse lines generated exhibits small pharyngeal arches (PAs), which are the main precursors of the head. Mutant embryos die around mid-gestation, most likely as a result of defective vasculature. We mapped the ENU-mediated point mutation within Mortalin. My thesis work aims to understand how Mortalin controls embryonic development. Mortalin is ubiquitously expressed before mid-gestation. Then its expression increases in the PAs and cranial ganglia. In older embryos, mortalin is expressed in muscle and nervous tissue. To determine which molecular mechanisms are affected in the mutant, gene expression profil revealed the induction of genes involved in the response to endoplasmic reticulum (ER) stress, called UPR. The role of the UPR is to restore homeostasis in the ER. I found that Mortalin regulates the UPR by interacting with BiP, a direct regulator of this pathway. Sustained activation of UPR leads to apoptosis, which is observed in our mutant. Cell cycle has been analyzed to investigate the cause of the reduced embryonic size in our mutant. The length of the S phase was found longer in the mutant, indicating that Mortalin also regulates cell cycle. All together, these data suggest that Mortalin is required for cell survival during development, in part by controlling the UPR

Since ancient times, master builders have used arches to cover large spans in masonry structures. As a consequence, nowadays the safety assessment of these structural elements plays a fundamental role in the conservation of built cultural heritage. Due to their frequent occurrence, support displacements are one of the primary sources of damage for masonry arches. Among the potential causes of support displacements, slow-moving landslides have received very little attention from the scientific community. The present thesis is motivated by the observation of extensive and severe damage in the arches of historic masonry churches exposed to slow-moving landslides. These phenomena produce a combination of vertical and horizontal supports displacements, whose effect on the arch structural behaviour has never been thoroughly investigated in the literature, especially in the framework of large displacements. In view of the above, this thesis aims at providing a full understanding of the mechanics of masonry arches subjected to large support displacements, with special attention to inclined displacements. The methodology used to accomplish this goal included both experimental tests and numerical analyses on a segmental scaled dry-joint masonry arch subjected to different combinations of horizontal and vertical support displacements. The numerical simulations were carried out in the framework of large displacements using two different numerical approaches based on finite element (FE) and rigid block (RB) modelling. A micro-modelling strategy was adopted, where the arch was modelled as an assemblage of voussoirs, very stiff and infinitely resistant in compression in the FE model and rigid in the RB model, interacting at no-tension friction interfaces. Preliminary numerical simulations, aimed at designing the experimental set-up and gaining a first insight in the arch response, were carried out considering the arch as a rigid-no tension structure. To this aim, a very large value of interface normal stiffness was adopted in the FE model. A large experimental campaign was performed on a 1:10 small-scale model built as a dry-joint assemblage of voussoirs made of a bicomponent composite material. The results of the tests allowed, for the first time in the literature, to accurately assess the effect of the direction of the imposed support displacements on the arch response in the framework of large displacements. The comparison between numerical and experimental results showed that the numerical models were not able to accurately predict the experimental response. To investigate this discrepancy, a sensitivity analysis on the effect of the interface normal stiffness on the FE predictions was performed. The results demonstrated that the difference between numerical and experimental results could be attributed due to the imperfections, and resulting deformability, of the joints of the physical model. A strategy to include imperfections in the numerical modelling, consisting in calibrating the interface normal stiffness based on the experimental results, was thus proposed and validated by performing further FE simulations, whose results were in very good agreement with the experimental evidence. Finally, to investigate the effect of geometrical imperfections on the arch response, a further experimental test was performed on a physical model made of bicomponent composite voussoirs exhibiting more imperfections. The test was simulated using a FE calibrated model to further validate the strategy proposed to model imperfections. The comparison between the experimental results for the two tested physical models showed that imperfections play a fundamental role in the response of small-scale arches to large support displacements. Furthermore, reducing the interface normal stiffness with respect to the large value adopted to model rigid interfaces proved to be an effective strategy to simulate the amount of imperfections of the experimental models.
Desde la antigüedad, los maestros constructores han utilizado el arco como elemento estructural para salvar grandes luces en estructuras de mampostería. En consecuencia, para la conservación del patrimonio arquitectónico es hoy en día de fundamental importancia la correcta verificación estructural de este tipo de elementos. Se ha observado frecuentemente que el desplazamiento de los apoyos es una de las principales causas de daño en arcos de mampostería. De entre las distintas causas que pueden provocar dicho desplazamiento, el deslizamiento de tierras ha recibido poca atención por parte de la comunidad científica. La presente tesis encuentra su motivación en el daño extenso y severo observado en los arcos de las iglesias de mampostería ubicadas en zonas expuestas a deslizamiento de tierras. Este fenómeno produce una combinación de desplazamientos verticales y horizontales, cuyo efecto en el comportamiento estructural de los arcos no ha sido investigado en profundidad, especialmente en lo relativo a grandes desplazamientos. Esta tesis aspira a contribuir al conocimiento del comportamiento mecánico de los arcos de mampostería sometidos a grandes desplazamientos de apoyos, con especial atención a los desplazamientos inclinados. La metodología utilitzada para dicho fin incluye ensayos experimentales y análisis numéricos en un modelo a escala de un arco de mampostería a junta seca. El modelo fue ensayado bajo diferentes combinaciones de desplazamientos horizontales y verticales en uno de sus apoyos. La simulación numérica fue desarrollada en el marco de grandes desplazamientos usando dos métodos numéricos diferentes: un modelo de elementos finitos (FE) y un modelo de bloques rígidos (RB). Los modelos fueron concebidos como un conjunto de dovelas rígidas con infinita resistencia a compresión en el modelo FE y como dovelas infinitamente rígidas en el modelo RB. En ambos modelos la interfaz entre dovelas fue modelada sin resistencia a tracción. Con el objetivo de diseñar la configuración experimental y adquirir una comprensión inicial de la respuesta del arco, se llevaron a cabo simulaciones numéricas preliminares en las cuales se consideró al arco estudiado como una estructura rígida. Para ello en el modelo FE del arco, la rigidez normal de la interfaz fue inicialmente caracterizada con un valor muy elevado. La campaña experimental fue llevada a cabo en modelos a escala 1:10. Los resultados de los ensayos experimentales permitieron, por primera vez en la literatura, un análisis preciso del efecto que tiene la dirección del desplazamiento impuesto en el comportamiento del arco en marco de grandes desplazamientos. La comparaci ón entre los resultados numéricos y experimentales mostró que los modelos numéricos no eran capaces de capturar de manera precisa la respuesta experimental. Para investigar esta discrepancia, se realizó un estudio de sensibilidad relativo al efecto de la rigidez normal de la interfaz sobre las predicciones del modelo FE. Los resultados demostraron que la diferencia entre los resultados numéricos y experimentales se debía a las imperfecciones de las juntas del modelo físico. Como consecuencia, se propuso la inclusión de imperfecciones en el modelo numérico. Para ello se calibró la rigidez normal de la interfaz según los resultados experimentales y el modelo se validó con nuevas simulaciones. Finalmente, con el fin de investigar el efecto de las imperfecciones en la respuesta del arco, se llevó a cabo otro ensayo con el mismo modelo experimental, pero añadiéndole imperfecciones. El ensayo fue simulado con un modelo calibrado FE. Los resultados obtenidos mostraron que las imperfecciones juegan un rol fundamental en la respuesta de arcos a pequeña escala con grandes desplazamientos en los apoyos. Además, la reducción de la rigidez normal de la interfaz con respecto al valor muy elevado inicialmente adoptado demostr ó ser una estrategia efectiva para simular las imperfecciones de los modelos experimentales.
Fin dall’antichità, i maestri costruttori hanno utilizzato gli archi per coprire grandi luci nelle strutture in muratura. Di conseguenza, ad oggi la valutazione della sicurezza di questi elementi strutturali gioca un ruolo fondamentale nella conservazione del patrimonio architettonico. A causa del loro frequente verificarsi, gli spostamenti degli appoggi sono una delle principali fonti di danno per gli archi in muratura. Tra le potenziali cause di questi spostamenti, le frane a cinematica lenta hanno ricevuto pochissima attenzione da parte della comunità scientifica. La presente tesi è motivata dall'osservazione di danni ingenti negli archi di chiese storiche in muratura interessate da frane a cinematica lenta. Questi fenomeni producono una combinazione di spostamenti verticali e orizzontali agli appoggi, il cui effetto sul comportamento strutturale dell'arco non è mai stato studiato a fondo in letteratura, soprattutto nell’ambito di grandi spostamenti. Alla luce di queste osservazioni, questa tesi si propone di fornire una piena comprensione della meccanica degli archi in muratura soggetti a grandi spostamenti degli appoggi, con particolare attenzione agli spostamenti inclinati. La metodologia utilizzata per raggiungere questo obiettivo ha incluso sia prove sperimentali che analisi numeriche su un arco ribassato in muratura di giunti a secco in piccola scala, in cui sono state applicate diverse combinazioni di spostamenti orizzontali e verticali in corrispondenza di un appoggio. Le simulazioni numeriche sono state eseguite nell’ambito dei gradi spostamenti utilizzando due diversi approcci numerici basati su una modellazione ad elementi finiti (FE) ed una modellazione a blocchi rigidi (RB). È stata adottata una strategia di micro-modellazione, in cui l'arco è stato modellato come un assemblaggio di blocchi, molto rigidi e infinitamente resistenti a compressione nel modello FE e infinitamente rigidi nel modello RB. In entrambi i modelli i blocchi erano collegati da interfacce senza resistenza a trazione. Simulazioni numeriche preliminari, finalizzate a progettare il set-up sperimentale e ad acquisire una prima conoscenza della risposta dell'arco, sono state eseguite considerando l'arco come una struttura rigida non resistente a trazione. A tal fine, nel modello FE è stato adottato un valore molto elevato di rigidezza normale delle interfacce. Un’ampia campagna sperimentale è stata eseguita su un modello in scala 1:10 costruito come un assemblaggio a secco di blocchi realizzati con un materiale composito bicomponente. I risultati delle prove sperimentali hanno permesso, per la prima volta in letteratura, di valutare con precisione l'effetto della direzione degli spostamenti imposti sulla risposta dell'arco nell’ambito dei grandi spostamenti. Il confronto tra i risultati numerici e sperimentali ha mostrato che i modelli numerici non erano in grado di cogliere in maniera accurata la risposta sperimentale, specialmente in termini di spostamento ultimo al collasso. Al fine di indagare le ragioni di questa discrepanza, è stata quindi eseguita un'analisi di sensitività relativa all’effetto della rigidezza normale delle interfacce sulle previsioni del modello FE. I risultati hanno dimostrato che la differenza tra risultati numerici e sperimentali poteva essere attribuita alle imperfezioni, e conseguente deformabilità, delle interfacce del modello fisico. Una strategia per includere le imperfezioni nella modellazione numerica, consistente nel calibrare la rigidezza normale delle interfacce sulla base dei risultati sperimentali, è stata quindi proposta e validata attraverso ulteriori simulazioni FE, i cui risultati si sono rivelati in ottimo accordo con le evidenze sperimentali. Infine, per indagare l'effetto delle imperfezioni geometriche sulla risposta dell'arco, è stata eseguita un’ulteriore prova sperimentale su un modello fisico costituito da blocchi dello stesso materiale composito bicomponente che presentavano però più imperfezioni. Al fine di validare ulteriormente la strategia proposta per modellare le imperfezioni, la prova sperimentale è stata simulata utilizzando un modello FE calibrato. Il confronto tra i risultati sperimentali per i due modelli fisici ha mostrato che le imperfezioni giocano un ruolo fondamentale nella risposta di archi in piccola scala a grandi spostamenti degli appoggi. Inoltre, ridurre la normale rigidezza dell'interfaccia rispetto al valore molto alto adottato per modellare interfacce rigide si è rivelata una strategia efficace per simulare la quantità di imperfezioni dei modelli sperimentali
Enginyeria de la construcció

The objective of this research project involves determining a seismic response modification factor for three-hinge glulam Tudor arches. In an attempt to meet this objective, the methods and procedures outlined in FEMA technical document P-695 were implemented on the provided arch designs. Computational models were created using finite elements within OpenSees to accurately depict the behavior of the arch. Incremental dynamic analyses were conducted on each of the provided designs and collapse margin ratios were determined allowing performance groups to be evaluated for each of seven design R-values within two gravity load cases. With the performance groups evaluated, it was determined that only groups within the low gravity load level designs were successfully able to pass, none of the groups designed for high gravity loads passed the evaluations. Within P-695, all performance groups associated with a given design R-value must pass the evaluations for that R-value to be deemed acceptable for use in designs. Because of the implications of this requirement, a seismic response modification factor could not be determined for this type of structural system within the scope of this project.
Master of Science

Since ancient times, master builders have used arches to cover large spans in masonry structures. As a consequence, nowadays the safety assessment of these structural elements plays a fundamental role in the conservation of built cultural heritage. Due to their frequent occurrence, support displacements are one of the primary sources of damage for masonry arches. Among the potential causes of support displacements, slow-moving landslides have received very little attention from the scientific community. The present thesis is motivated by the observation of extensive and severe damage in the arches of historic masonry churches exposed to slow-moving landslides. These phenomena produce a combination of vertical and horizontal supports displacements, whose effect on the arch structural behaviour has never been thoroughly investigated in the literature, especially in the framework of large displacements. In view of the above, this thesis aims at providing a full understanding of the mechanics of masonry arches subjected to large support displacements, with special attention to inclined displacements. The methodology used to accomplish this goal included both experimental tests and numerical analyses on a segmental scaled dry-joint masonry arch subjected to different combinations of horizontal and vertical displacements at one support. The numerical simulations were carried out in the framework of large displacements using two different numerical approaches based on finite element (FE) and rigid block (RB) modelling. A micro-modelling strategy was adopted, where the arch was modelled as an assemblage of voussoirs, very stiff and infinitely resistant in compression in the FE model and rigid in the RB model, interacting at no-tension friction interfaces. Preliminary numerical simulations, aimed at designing the experimental set-up and gaining a first insight in the arch response, were carried out considering the arch as a rigid-no tension structure. To this aim, a very large value of interface normal stiffness was adopted in the FE model. A large experimental campaign was performed on a 1:10 small-scale model built as a dry-joint assemblage of voussoirs made of a bicomponent composite material. The results of the tests allowed, for the first time in the literature, to accurately assess the effect of the direction of the imposed support displacements on the arch response in the framework of large displacements. The comparison between numerical and experimental results showed that the numerical models were not able to accurately predict the experimental response, especially in terms of ultimate displacement capacity. To investigate this discrepancy, a sensitivity analysis on the effect of the interface normal stiffness on the FE predictions was performed. The results demonstrated that the difference between numerical and experimental results could be attributed due to the imperfections, and resulting deformability, of the joints of the physical model. A strategy to include imperfections in the numerical modelling, consisting in calibrating the interface normal stiffness based on the experimental results, was thus proposed and validated by performing further FE simulations, whose results were in very good agreement with the experimental evidence. Finally, to investigate the effect of geometrical imperfections on the arch response, a further experimental test was performed on a physical model made of bicomponent composite voussoirs exhibiting more imperfections. The test was simulated using a FE calibrated model to further validate the strategy proposed to model imperfections. The comparison between the experimental results for the two tested physical models showed that imperfections play a fundamental role in the response of small-scale arches to large support displacements. Furthermore, reducing the interface normal stiffness with respect to the large value adopted to model rigid interfaces proved to be an effective strategy to simulate the amount of imperfections of the experimental models.

The motion of a shallow arch subjected to random loading is investigated. It is expected that the arch will vibrate about its initial stable configuration under low intensity loading, but will snap back and forth about its horizontal axis under high intensity loading. The parameter of interest is the time of first snap-through of the shallow arch under random load. This is defined as the time taken for the arch to snap to the other side of the horizontal axis. The statistics of the time to first snap-through, such as the mean time to failure as well as its probability distribution. are determined. Most of the work treats one response mode. In the first part of the study, the critical random loading for dynamic snap-through of the shallow arch was investigated using the method of computer simulation. The random excitation was assumed to be a stationary white-noise process. The primary object was to determine the critical power spectral density parameter of the random excitations. The vanishing or diminishing of the average frequency of snap-through was used to estimate this parameter. An exact value of the critical random loading parameter could not be obtained using this criterion since it was based on numerical integration of the non-linear equation of motion and computer simulation which is expensive and time-consuming. However, the critical value or range of critical values of intensity of random excitations could be estimated with a reasonable degree of accuracy. The second part of the study dealt with the first-passage problem. The exact solution of the first-passage problem is available for only a limited class of problems. In this study, the solution was obtained using numerical approximation techniques and computer simulation. For an oscillator subjected to white noise, the displacement and velocity process are governed by the Fokker-Planck-Kolmogorov (FPK) equation. The finite difference method was used to solve the derived FPK equation of the energy envelope of the equation of motion of the arch subjected to white-noise excitation. Solutions were obtained in terms of the mean time to failure, and the probability distribution function of the time to failure. A computer program for the Monte Carlo simulation of the response of the arch subjected to random loads was also developed. A large number of records of the random excitations were simulated and these were used as input in the numerical integration of the equation of motion. The Runge-Kutta method was used to obtain the time history of the displacement response, and the time at which the response exceeded the critical threshold was recorded. Statistics of the time to first snap-through were obtained and these were then used to select an empirical distribution model for the first-passage time. The results of the approximate analysis were compared with those from the simulation. Results of both methods were in close agreement. The effect of including more than one mode in the equation of motion was also studied. Multi-mode approximations of up to four modes were considered in the analysis. It was found that the results of the multi-mode approximations are significantly different from the one-mode approximation. The effect of nonstationary random excitation on the time to first snap-through was also investigated using computer simulation.
Ph. D.

I've titled my thesis, "Intrinsics" because my architectural design is an attempt to respond to what is inherent in the materials, in the way materials are joined, in the flow of forces through the structure, in the site and surroundings, and in the human nature of a person using the building type I'm designing. This is a tectonic approach, so my thesis is also "An Exploration of Tectonic Expression" with a Montessori school as a project vehicle. The site is next to the Roanoke Public Library in Elmwood Park in Roanoke, Virginia. The primary materials are glue-laminated wood beams and arches, metal connectors, and reinforced concrete walls. I explored what can happen if each layer of a glue-laminated member is allowed to act independently, separating from the girder in appropriate places to recombine into a new whole. The monolith transforms into a pattern of parts.
Master of Architecture

Abstract The influence of the X and Y chromosomes on the size and shape of the dental arches and occlusion as well as on craniofacial cephalometric dimensions, angles and dimensional ratios is studied. The material consists of Finnish patients with sex chromosome aneuploidies and normal population controls from the "Kvantti Study" series, which was collected in the 1970's and 1980's at the Institute of Dentistry, University of Turku. The patients are five individuals with complete testicular feminization (CTF), eight 47,XYY males, and fourteen 45,X/46,XX females. The controls are population female and male controls, as well as five first degree relatives of the individuals with CTF, three of the 47,XYY males and nine of the 45,X/46,XX females studied. Dental arch dimensions and occlusion as well as craniofacial cephalometric dimensions, angles and dimensional ratios are measured from dental study casts and standardized lateral cephalograms. The results show that the presence of the Y chromosome in 46,XY females and the supernumerary Y chromosomal gene(s) in 47,XYY males result in the enlargement of the dental arches and craniofacial dimensions without substantial effects on dimensional ratios and plane angles, but with special influence on the growth of the mandibular corpus. The reduction of X chromosomal genetic material in 45,X/46,XX females results in the reduction of craniofacial dimensions, affecting dimensional ratios and especially plane angles of the cranial base.

In the past few decades, there are quite a number of Pai-fangs built in the indigenous villages of the New Territories in Hong Kong and the number appears to be on the rise. The phenomenon of having so many pai-fangs in NT indigenous villages in Hong Kong could not be coincidental. They must be built as a result of some negotiation among different stakeholders – the villagers must agree, or at least do not object to the erection of pai-fang in their neighborhood; the government must also agree as they very likely take up government land and many different government departments need to be involved to build the structure. Pai-fang (牌坊) (literally archway) is a traditional form of Chinese architecture that is a physical gateway to a village. In the past few decades, there were quite a few pai-fangs built in the indigenous villages of the New Territories (NT)1 in Hong Kong and the number appeared to be on the rise. This kind of architecture neither provides physical accommodation for living or storage nor do they provide temporary shelter like a pavilion. In addition, the pai-fangs in Hong Kong are not aesthetically distinguished, especially when compared with those in Chinatowns or in the tourism spots in other countries. Nonetheless, they are increasingly popular in the NT indigenous villages in Hong Kong. It would appear that there are other reasons attributed to their origins and their increased popularity in Hong Kong other than their function or their aesthetic value. In a practical modern society like Hong Kong, when land and resource is scare, who would provide funding to build such architecture and who would find value in such architecture? The research issue is to address the phenomenon of pai-fang proliferation in the NT indigenous villages which may reflect some historical and socio-political factors in Hong Kong. Indeed, not much work has been done so far on researching pai-fangs in general in Hong Kong, not to mention research focusing on the recent trend in the increasing number of pai-fangs in the NT indigenous villages. Obviously, there is a gap in this area and this dissertation aims to cover the gap in this research by investigating into the reasons for the proliferation of pai-fang in NT indigenous villages, which may reflect some underlying historical and socio-political factors that are unique to Hong Kong. 1 For the sake of definition covered by this dissertation, the indigenous villages of New Territories exclude the indigenous villages in the Outlying Islands and New Kowloon. --------------- ------------------------------------------------------------ --------------- ------------------------------------------------------------
published_or_final_version
Conservation
Master
Master of Science in Conservation

No presente estudo foi examinado em detalhe a anatomia da musculatura dorsal dos arcos branquiais de 70 espécies, pertencentes a 64 gêneros, representando todas as famílias atualmente reconhecidas de Characiformes. Um total de 22 músculos foram descritos e documentados para cada espécie examinada, e com base nas variações observadas foram propostos 33 caracteres exclusivos da musculatura dorsal dos arcos branquiais. De modo geral, muitos dos estados de caracteres observados estão amplamente distribuídos em espécies representantes de diversas famílias, variando muitas vezes em representantes da mesma família, com um número menor de caracteres restritos a alguns táxons. Uma análise filogenética incluindo apenas os caracteres de musculatura dorsal dos arcos branquiais resultou em 18829 cladogramas igualmente mais parcimoniosos (157 passos, IC=16 IR=34) com consenso estrito muito pouco resolvido devido não só ao reduzido número de caracteres em relação ao número de táxons, mas também há grande incongruência na distribuição dos estados de caracteres. Contudo, a discussão da variação observada neste complexo anatômico, em um contexto filogenético, tomando por base hipóteses já disponíveis na literatura sobre relações de parentesco na ordem Characiformes evidencia a presença de caracteres que corroboram a hipóteses baseadas em outros complexos de caracteres, em diversos níveis supraespecíficos
In the present study the anatomy of the dorsal gill-arch muscles of 70 species, comprising 64 genera, representing all currently recognized families of the Characiformes was examined in detail. A total of 22 muscles were described and documented for each examined species, and based on the variation observed 33 characters of the dorsal musculature of the gill arch were proposed. Overall, many of the observed character states are widely distributed across species in different families, and in many instances they vary within a single family, and a smaller number of characters states restricted to a few taxa. A phylogenetic analysis including only characters derived from the dorsal gill-arch musculature resulted in 18829 most parsimonious cladograms (157 steps, CI=16 RI=34), with a poorly resolved strict consensus, due not only to the reduced number of characters relative to the number of taxa, but also to the high level of incongruence in the distribution of characters states. However, the discussion of the variation observed in this anatomical complex, in the context of hypotheses available in the literature about phylogenetic relationships within the Characiformes, highlights the presence of various character states from the dorsal gill arch muscles that corroborate hypotheses based on different character complexes, at various supraespecific levels within the order

Le développement cranio-facial est un processus complexe qui implique interactions tissulaires et différenciations cellulaires. La façon dont ces processus sont coordonnés lors de l'embryogenèse reste évasive. Perturber ce développement coordonné provoque un large éventail de malformations. Afin de trouver de nouveaux gènes impliqués dans le développement de la tête, un criblage phénotypique a été réalisé par mutagenèse. L'une des lignées de souris obtenues montre des malformations au niveau des arches pharyngées (AP), qui sont les précurseurs de la tête. Ces mutants meurent à mi gestation, due à des problèmes vasculaires. La mutation ponctuelle générée a été localisé dans le gène Mortalin. Mon travail de thèse vise à comprendre comment Mortalin contrôle le développement embryonnaire. Mortalin est exprimée de manière ubiquitaire, puis son expression augmente au niveau des AP, dans les tissus musculaires et nerveux. Pour déterminer les mécanismes moléculaires affectées chez ce mutant, un profil d'expression génique a révélé l'induction de gènes impliqués dans la réponse au stress du réticulum endoplasmique (RE), appelée UPR, dont le rôle est de rétablir l'homéostasie du RE. Mortalin est impliqué dans le contrôle de l'UPR en interagissant avec BiP, un régulateur direct de cette voie. L'activation soutenue de l'UPR entraîne l'apoptose, ce que nous observons chez nos mutants. De plus, l'analyse du cycle cellulaire indique que la phase S est plus longue chez le mutant, suggérant que Mortalin régule le cycle cellulaire. Ainsi, l'ensemble des données suggère que Mortalin est nécessaire pour la survie des cellules au cours du développement
The development of the head is a complex process that involves tissue interaction and cellular differentiation. Precisely how these processes are coordinated during embryogenesis remains elusive. Disruption of this coordinated development causes a wide range of malformations. In order to find new genes involved in the development of the head, a phenotype-driven ENU screen was performed. One of the mouse lines generated exhibits small pharyngeal arches (PAs), which are the main precursors of the head. Mutant embryos die around mid-gestation, most likely as a result of defective vasculature. We mapped the ENU-mediated point mutation within Mortalin. My thesis work aims to understand how Mortalin controls embryonic development. Mortalin is ubiquitously expressed before mid-gestation. Then its expression increases in the PAs and cranial ganglia. In older embryos, mortalin is expressed in muscle and nervous tissue. To determine which molecular mechanisms are affected in the mutant, gene expression profil revealed the induction of genes involved in the response to endoplasmic reticulum (ER) stress, called UPR. The role of the UPR is to restore homeostasis in the ER. I found that Mortalin regulates the UPR by interacting with BiP, a direct regulator of this pathway. Sustained activation of UPR leads to apoptosis, which is observed in our mutant. Cell cycle has been analyzed to investigate the cause of the reduced embryonic size in our mutant. The length of the S phase was found longer in the mutant, indicating that Mortalin also regulates cell cycle. All together, these data suggest that Mortalin is required for cell survival during development, in part by controlling the UPR

Polish composer Hanna Kulenty (1961- ) is considered a doyen among twenty-first century composers. Her compositions span over 30 years and comprise a wide range of works including solo instrumental works, operas, small and large chamber works, orchestral works and film scores. She experiments and incorporates various post-tonal era elements and devices into her compositions, often creating permanent tension and extreme emotional intensity. This study provides a detailed biography of Kulenty, a brief discussion pertaining to the development of music during the tonal and post-tonal eras and investigates Kulenty's approach to key musical traits (including melody, rhythm and harmony) in the selected string ensemble works in order to determine her musical idiom. Furthermore, this study serves as an essential reference for Kulenty's string quartets and quintet composed between 1984 and 2013. A style transformation pertaining to the selected string ensemble works is discussed. In her early compositions, Kulenty made use of 'polyphony of arches' comprising layers of arches within a large arch structure. Her more recent contributions make use of a single arch moving through different time dimensions, referred to as 'polyphony of time dimensions'. Ultimately, this study serves as a primary foundation for researchers who wish to investigate and discuss any stylistic aspects of the composer's oeuvre.
Mini Dissertation (MMus)--University of Pretoria, 2017.
Music
MMus
Unrestricted

В дипломній роботі виконано проектування багатоповерхової житлової будівлі із моделюванням склепінь та куполів поверхнями другого порядку з застосуванням конструктивних параметрів.
In the thesis work the design of multi-storey residential building with arches and domes modeling quadric using design parameters