Mechanical behaviour and rupture of normal and pathological human ascending aortic wall

The mechanical properties of aortic wall, both healthy and pathological, are needed in order to develop and improve diagnostic and interventional criteria, and for the development of mechanical models to assess arterial integrity. This study focuses on the mechanical behaviour and rupture conditions of the human ascending aorta and its relationship with age and pathologies. Fresh ascending aortic specimens harvested from 23 healthy donors, 12 patients with bicuspid aortic valve (BAV) and 14 with aneurysm were tensile-tested in vitro under physiological conditions. Tensile strength, stretch at failure and elbow stress were measured. The obtained results showed that age causes a major reduction in the mechanical parameters of healthy ascending aortic tissue, and that no significant differences are found between the mechanical strength of aneurysmal or BAV aortic specimens and the corresponding age-matched control group. The physiological level of the stress in the circumferential direction was also computed to assess the physiological operation range of healthy and diseased ascending aortas. The mean physiological wall stress acting on pathologic aortas was found to be far from rupture, with factors of safety (defined as the ratio of tensile strength to the mean wall stress) larger than six. In contrast, the physiological operation of pathologic vessels lays in the stiff part of the response curve, losing part of its function of damping the pressure waves from the heart.

Materials Research for HiPER Laser Fusion Facilities: Chamber Wall, Structural Material and Final Optics

The European HiPER project aims to demonstrate commercial viability of inertial fusion energy within the following two decades. This goal requires an extensive Research &Development program on materials for different applications (e.g., first wall, structural components and final optics). In this paper we will discuss our activities in the framework of HiPER to develop materials studies for the different areas of interest. The chamber first wall will have to withstand explosions of at least 100 MJ at a repetition rate of 5-10 Hz. If direct drive targets are used, a dry wall chamber operated in vacuum is preferable. In this situation the major threat for the wall stems from ions. For reasonably low chamber radius (5-10 m) new materials based on W and C are being investigated, e.g., engineered surfaces and nanostructured materials. Structural materials will be subject to high fluxes of neutrons leading to deleterious effects, such as, swelling. Low activation advanced steels as well as new nanostructured materials are being investigated. The final optics lenses will not survive the extreme ion irradiation pulses originated in the explosions. Therefore, mitigation strategies are being investigated. In addition, efforts are being carried out in understanding optimized conditions to minimize the loss of optical properties by neutron and gamma irradiation

Towards the foundation of a global modes concept

A contribution is presented, intended to provide theoretical foundations for the ongoing efforts to employ global instability theory for the analysis of the classic boundary-layer flow, and address the associated issue of appropriate inflow/outflow boundary conditions to close the PDE-based global eigenvalue problem in open flows. Starting from a theoretically clean and numerically simple application, in which results are also known analytically and thus serve as a guidance for the assessment of the performance of the numerical methods employed herein, a sequence of issues is systematically built into the target application, until we arrive at one representative of open systems whose instability is presently addressed by global linear theory applied to open flows, the latter application being neither tractable theoretically nor straightforward to solve by numerical means. Experience gained along the way is documented. It regards quantification of the depar- ture of the numerical solution from the analytical one in the simple problem, the generation of numerical boundary layers at artificially truncated boundaries, no matter how far the latter are placed from the region of highest flow gradients and, ultimately the impracti- cally large number of (direct and adjoint) modes necessary to project an arbitrary initial perturbation and follow its temporal evolution by a global analysis approach, a finding which may question the purported robustness reported in the literature of the recovery of optimal perturbations as part of global analyses yielding under-resolved eigenspectra.

Wave-like Disturbances on the Downstream Wall of an Open Cavity

This contribution presents results of an incompressible two-dimensional flow over an open cavity of fixed aspect ratio (length/depth) L/D = 2 and the coupling between the three dimensional low frequency oscillation mode confined in the cavity and the wave-like disturbances evolving on the downstream wall of the cavity in the form of Tollmien-Schlichting waves. BiGlobal instability analysis is conducted to search the global disturbances superimposed upon a two-dimensional steady basic flow. The base solution is computed by the integration of the laminar Navier-Stokes equations in primitive variable formulation, while the eigenvalue problem (EVP) derived from the discretization of the linearized equations of motion in the BiGlobal framework is solved using an iterative procedure. The formulation of the BiGlobal EVP for the unbounded flow in the open cavity problem introduces additional difficulties regarding the flow-through boundaries. Local analysis has been utilized for the determination of the proper boundary conditions in the upper limit of the downstream region

Amplificador de señal analógico basado en conceptos biomiméticos. Desarrollo de modelos computacionales y validación experimental

La presente tesis doctoral estudia las características de un transductor acústico bioinspirado en la estructura del maxilar inferior de un Zifio de Couvier (Ziphius cavirostris). El mecanismo de funcionamiento del sensor se basa en las características de un sistema acoplado formado por los distintos componentes acústicos identificados en el maxilar. Para analizar las características del sensor se propone un modelo simplificado 2D que consta de una cavidad cerrada con forma de bocina acoplada a una lengüeta. Una parte de la lengüeta se encuentra dentro de la cavidad y otra en el exterior. Dicha lengüeta detecta los cambios de presión acústica y las vibraciones generadas por el sonido y las transmite con ondas de flexión al interior de la cavidad. La excitación prolongada sobre la placa puede provocar la activación de los modos propios del sistema acoplado. Dichos modos se caracterizan porque presentan un máximo de presión en el cono de la bocina la cual a su vez actúa como un amplificador acústico. Mediante el Método de los elementos Finitos se analizan las características acústicas del sensor y se construye un prototipo experimental para validar los resultados evaluados en el modelo numérico. Se propone una metodología numérica que permite desarrollar y validar un elemento tetraédrico para caracterizar el comportamiento isotrópico de los medios porosos. La metodología permite construir elementos de línea y bidimensionales. A partir de esta metodología se desarrolla un elemento plano ortotrópico. Se realiza un modelo de la cavidad en el que una de las paredes de la bocina está constituida por material poroso y se une la parte exterior de la lengüeta a dicho material para que constituya una viga sobre un apoyo elástico. Se calcula la respuesta modal y se discuten los efectos del material poroso en la eficiencia del transductor y las posibles mejoras a introducir en el mismo. SUMMARY This Thesis studies the characteristics of an acoustic transducer bioinspired by the structure of the lower maxilla of an odontoceto. In this case a Cuvier’s beaked whale (Ziphius cavirostris). The transducer working mechanism is based in a coupled system, with components identified in the maxilla. To analyze the transducer a simplified 2D model composed by a horn shaped closed cavity is modeled. The cavity is coupled with a flat belt. The belt has one part inside the cavity and the other part outside of it. The belt traverses the cavity wall and it is in charge to pick the vibrations from outside and introduce it inside the cavity. The transmission is obtained through the belt bending. A sustained external load with the right frequency contents will allow the system to reach a stationary pressure intensity distribution inside the cavity. Frequencies with modal shapes that show an important intensity increase at the horn tip are of special interest because of the signal amplification. A finite element model is constructed to study the transducer coupled modes and a prototype is constructed to validate the numerical results. A numerical methodology to construct and validate a tetrahedral finite element for isotropic porous materials is presented. The methodology allows constructing linear and 2D elements. It is extended to model orthotropic porous materials behavior. At the end, one of the horn walls is made of an orthotropic material and the external belt is glued to it in order to configure a belt over an elastic foundation. Modal response is evaluated and the porous material effects in the transducer efficiency and further improvements are discussed.

Intensive Metrics for the Study of the Evolution of Open Source Projects: Case Studies from Apache Software Foundation Projects

Based on the empirical evidence that the ratio of email messages in public mailing lists to versioning system commits has remained relatively constant along the history of the Apache Software Foundation (ASF), this paper has as goal to study what can be inferred from such a metric for projects of the ASF. We have found that the metric seems to be an intensive metric as it is independent of the size of the project, its activity, or the number of developers, and remains relatively independent of the technology or functional area of the project. Our analysis provides evidence that the metric is related to the technical effervescence and popularity of project, and as such can be a good candidate to measure its healthy evolution. Other, similar metrics -like the ratio of developer messages to commits and the ratio of issue tracker messages to commits- are studied for several projects as well, in order to see if they have similar characteristics.

Plasma–wall interaction in laser inertial fusion reactors: novel proposals for radiation tests of first wall materials

Dry-wall laser inertial fusion (LIF) chambers will have to withstand strong bursts of fast charged particles which will deposit tens of kJ m−2 and implant more than 1018 particles m−2 in a few microseconds at a repetition rate of some Hz. Large chamber dimensions and resistant plasma-facing materials must be combined to guarantee the chamber performance as long as possible under the expected threats: heating, fatigue, cracking, formation of defects, retention of light species, swelling and erosion. Current and novel radiation resistant materials for the first wall need to be validated under realistic conditions. However, at present there is a lack of facilities which can reproduce such ion environments. This contribution proposes the use of ultra-intense lasers and high-intense pulsed ion beams (HIPIB) to recreate the plasma conditions in LIF reactors. By target normal sheath acceleration, ultra-intense lasers can generate very short and energetic ion pulses with a spectral distribution similar to that of the inertial fusion ion bursts, suitable to validate fusion materials and to investigate the barely known propagation of those bursts through background plasmas/gases present in the reactor chamber. HIPIB technologies, initially developed for inertial fusion driver systems, provide huge intensity pulses which meet the irradiation conditions expected in the first wall of LIF chambers and thus can be used for the validation of materials too.

Análisis de la influencia de distintos diseños de paraguas de micropilotes, pantalla de micropilotes, paraguas de jet grouting y pantallas de jet grouting en los asientos en superficie durante la ejecución de túneles perforados superficialmente

Ya en el informe acerca del estado de la tecnología en la excavación profunda y en la construcción de túneles en terreno duro presentado en la 7ª Conferencia en Mecánica de Suelos e Ingeniería de la Cimentación, Peck (1969) introdujo los tres temas a ser tenidos en cuenta para el diseño de túneles en terrenos blandos: o Estabilidad de la cavidad durante la construcción, con particular atención a la estabilidad del frente del túnel; o Evaluación de los movimientos del terreno inducidos por la construcción del túnel y de la incidencia de los trabajos subterráneos a poca profundidad sobre los asentamientos en superficie; o Diseño del sistema de sostenimiento del túnel a instalar para asegurar la estabilidad de la estructura a corto y largo plazo. Esta Tesis se centra en los problemas señalados en el segundo de los puntos, analizando distintas soluciones habitualmente proyectadas para reducir los movimientos inducidos por la excavación de los túneles. El objeto de la Tesis es el análisis de la influencia de distintos diseños de paraguas de micropilotes, pantalla de micropilotes, paraguas de jet grouting y pantallas de jet grouting en los asientos en superficie durante la ejecución de túneles ejecutados a poca profundidad, con objeto de buscar el diseño que optimice los medios empleados para una determinada reducción de asientos. Para ello se establecen unas premisas para los proyectistas con objeto de conocer a priori cuales son los tratamientos más eficientes (de los propuestos en la Tesis) para la reducción de asientos en superficie cuando se ha de proyectar un túnel, de tal manera que pueda tener datos cualitativos y algunos cuantitativos sobre los diseños más óptimos, utilizando para ello un programa de elementos finitos de última generación que permite realizara la simulación tensodeformación del terreno mediante el modelo de suelo con endurecimiento (Hardening Soil Small model), que es una variante elastoplástica del modelo hiperbólico, similar al Hardening Soil Model. Además, este modelo incorpora una relación entre deformación y el modulo de rigidez, simulando el diferente comportamiento del suelo para pequeñas deformaciones (por ejemplo vibraciones con deformaciones por debajo de 10-5 y grandes deformaciones (deformaciones > 10-3). Para la realización de la Tesis se han elegido cinco secciones de túnel, dos correspondiente a secciones tipo de túnel ejecutado con tuneladora y tres secciones ejecutados mediante convencionales (dos correspondientes a secciones que han utilizado el método Belga y una que ha utilizado el NATM). Para conseguir los objetivos marcados, primeramente se ha analizado mediante una correlación entre modelos tridimensionales y bidimensionales el valor de relajación usado en estos últimos, y ver su variación al cambio de parámetros como la sección del túnel, la cobertera, el procedimiento constructivo, longitud de pase (métodos convencionales) o presión del frente (tuneladora) y las características geotécnicas de los materiales donde se ejecuta el túnel. Posteriormente se ha analizado que diseño de pantalla de protección tiene mejor eficacia respecto a la reducción de asientos, variando distintos parámetros de las características de la misma, como son el empotramiento, el tipo de micropilotes o pilote, la influencia del arriostramiento de las pantallas de protección en cabeza, la inclinación de la pantalla, la separación de la pantalla al eje del túnel y la disposición en doble fila de la pantalla de pantalla proyectada. Para finalizar el estudio de la efectividad de pantalla de protección para la reducción de asiento, se estudiará la influencia de la sobrecarga cercanas (simulación de edificios) tiene en la efectividad de la pantalla proyectada (desde el punto de vista de reducción de movimientos en superficie). Con objeto de poder comparar la efectividad de la pantalla de micropilotes respecto a la ejecución de un paraguas de micropilotes se ha analizado distintos diseños de paraguas, comparando el movimiento obtenido con el obtenido para el caso de pantalla de micropilotes, comparando ambos resultados con los medidos en obras ya ejecutadas. En otro apartado se ha realizado una comparación entre tratamientos similar, comparándolos en este caso con un paraguas de jet grouting y pantallas de jet grouting. Los resultados obtenidos se han con valores de asientos medidos en distintas obras ya ejecutadas y cuyas secciones se corresponden a los empleados en los modelos numéricos. Since the report on the state of technology in deep excavation and tunnelling in hard ground presented at the 7th Conference on Soil Mechanics and Foundation Engineering, Peck (1969) introduced the three issues to be taken into account for the design of tunnels in soft ground: o Cavity Stability during construction, with particular attention to the stability of the tunnel face; o Evaluation of ground movements induced by tunnelling and the effect of shallow underground workings on surface settlement; o Design of the tunnel support system to be installed to ensure short and long term stability of the structure. This thesis focuses on the issues identified in the second point, usually analysing different solutions designed to reduce the movements induced by tunnelling. The aim of the thesis is to analyse the influence of different micropile forepole umbrellas, micropile walls, jet grouting umbrellas and jet grouting wall designs on surface settlements during near surface tunnelling in order to use the most optimal technique to achieve a determined reduction in settlement. This will establish some criteria for designers to know a priori which methods are most effective (of those proposed in the thesis) to reduce surface settlements in tunnel design, so that it is possible to have qualitative and some quantitative data on the optimal designs, using the latest finite element modelling software that allows simulation of the ground’s infinitesimal strain behaviour using the Hardening Soil Small Model, which is a variation on the elasto-plastic hyperbolic model, similar to Hardening Soil model. In addition, this model incorporates a relationship between strain and the rigidity modulus, simulating different soil behaviour for small deformations (eg deformation vibrations below 10-5 and large deformations (deformations > 10-3). For the purpose of this thesis five tunnel sections have been chosen, two sections corresponding to TBM tunnels and three sections undertaken by conventional means (two sections corresponding to the Belgian method and one corresponding to the NATM). To achieve the objectives outlined, a correlation analysis of the relaxation values used in the 2D and 3D models was undertaken to verify them against parameters such as the tunnel cross-section, the depth of the tunnel, the construction method, the length of step (conventional method) or face pressure (TBM) and the geotechnical characteristics of the ground where the tunnel is constructed. Following this, the diaphragm wall design with the greatest efficiency regarding settlement reduction was analysed, varying parameters such as the toe depth, type of micropiles or piles, the influence of bracing of the head protection diaphragm walls, the inclination of the diaphragm wall, the separation between the diaphragm wall and the tunnel axis and the double diaphragm wall design arrangement. In order to complete the study into the effectiveness of protective diaphragm walls ofn the reduction of settlements, the influence of nearby imposed loads (simulating buildings) on the effectiveness of the designed diaphragm walls (from the point of view of reducing surface movements) will be studied. In order to compare the effectiveness of micropile diaphragm walls regarding the installation of micropile forepole umbrellas, different designs of these forepole umbrellas have been analysed comparing the movement obtained with that obtained for micropiled diaphragm walls, comparing both results with those measured from similar completed projects. In another section, a comparison between similar treatments has been completed, comparing the treatments with a forepole umbrella by jet grouting and jet grouting walls. The results obtained compared with settlement values measured in various projects already completed and whose sections correspond to those used in the numerical models.

Elementos para una nueva metodología de cálculo de diques verticales

El comercio marítimo actual requiere buques de un tamaño cada vez mayor. Para dar servicio a estos buques los puertos tienen que ofrecer grandes calados y las obras de abrigo están cimentadas cada vez a mayor profundidad, particularmente en el caso de España que es un país con escasos puertos naturales y poca plataforma continental y la mayoría de sus puertos son exteriores. La construcción de obras de abrigo en calados tan grandes (hasta 50 metros de profundidad) resulta sumamente costosa, y dado que a esas profundidades generalmente el oleaje no rompe, la tipología más habitual es la de diques verticales, reflejantes puros, tanto por ahorro de costes como por impacto ambiental. Al ir a mayores calados las olas a las que se enfrentan los diques son cada vez mayores, y esto acusa el desconocimiento exacto de los fenómenos que hidrodinámicos que tienen lugar, y por tanto las deficiencias de los métodos de dimensionamiento de diques verticales empleados. La incertidumbre en la definición de los fenómenos involucrados lleva a la mayoración indiscriminada de las acciones y al sobredimensionamiento de los diques, con el consiguiente sobrecoste, y a otra conclusión más grave: el desconocimiento de los factores de seguridad reales. Esto obliga a continuar profundizando en los fundamentos de los fenómenos observados. La presente tesis se basa en el análisis de datos recogidos por la instrumentación del dique de Botafoc (Ibiza) desde el año 2003. Esta instrumentación es de las que ha ofrecido mediciones de temporales de forma más consistente en todo el mundo. El análisis de los datos conduce a una serie de resultados muy reveladores y novedosos en cuanto a la forma de las distribuciones de los empujes, la influencia del periodo del oleaje sobre las mismas, y la importancia de los flujos inducidos por el oleaje a través de las banquetas de cimentación. Todas las conclusiones alcanzadas están sólidamente justificadas desde el punto de vista teórico. También se ponen de manifiesto otros fenómenos interesantes que no eran objeto de la presente investigación como la importancia del retranqueo del espaldón. El alcance inicial de la tesis pretendía dar explicación a la influencia del periodo del oleaje sobre las distribuciones de presiones, sin embargo la gran cantidad de descubrimientos realizados llevan a pensar en la posibilidad de desarrollar una nueva metodología de cálculo de esfuerzos hidrodinámicos en diques verticales. Esta nueva metodología está en desarrollo por el autor de la presente tesis y será presentada en futuros trabajos. Además del importante avance conceptual del estado de la técnica que supone, otro producto de la investigación ha sido el desarrollo de dos patentes de invención y una tercera aún en desarrollo. Maritime trade nowadays requires ships of increasing size, and ports must go to deeper draughts to shelter those ships. In high depths vertical breakwaters are the most economical alternative; however there are many questions about reflection of waves not yet clarified. This uncertainties drive to oversize breakwaters and the corresponding rise in costs. Moreover the main issue is that safety margins are not known. This thesis is based on the analysis of data collected by instrumentation of the Botafoc breakwater (Ibiza) since 2003, having recorded a wide range of data. The data analysis leads to very interesting discovers such as the shape of the distribution of the pressures, the influence of wave period, and the importance of the wave induced flows through foundation. All conclusions reached are solidly justified from the theoretical point of view. Other interesting phenomena that were not the subject of this research have been revealed such as the importance of crown wall position. The initial scope of the thesis aimed to give explanation to the influence of the wave period on distributions of pressure; however the interesting discoveries made suggest developing a new methodology for calculating hydrodynamic efforts vertical breakwaters. This new methodology is currently under development by the author of this thesis and will be presented in future works. Besides the important conceptual advance the state of the art involved, another product of the research has been the development of two patents.

Comparative study of breakwater crown wall – calculation methods

An investigation was undertaken consisting of a state-of-the-art and comparative analysis of currently available methods for calculating the structural stability of wave walls in sloping breakwaters. A total of six design schemes are addressed. The conditions under which the formulations and ranges of validity are explicitly indicated by their authors, are given. The lack of definition in parameters to be used and aspects not taken into account in their investigations are discussed and the results of this analysis are given in a final table.

Plasma–wall interaction in laser inertial fusion reactors: novel proposals for radiation tests of first wall materials

Dry-wall laser inertial fusion (LIF) chambers will have to withstand strong bursts of fast charged particles which will deposit tens of kJ m−2 and implant more than 1018 particles m−2 in a few microseconds at a repetition rate of some Hz. Large chamber dimensions and resistant plasma-facing materials must be combined to guarantee the chamber performance as long as possible under the expected threats: heating, fatigue, cracking, formation of defects, retention of light species, swelling and erosion. Current and novel radiation resistant materials for the first wall need to be validated under realistic conditions. However, at present there is a lack of facilities which can reproduce such ion environments. This contribution proposes the use of ultra-intense lasers and high-intense pulsed ion beams (HIPIB) to recreate the plasma conditions in LIF reactors. By target normal sheath acceleration, ultra-intense lasers can generate very short and energetic ion pulses with a spectral distribution similar to that of the inertial fusion ion bursts, suitable to validate fusion materials and to investigate the barely known propagation of those bursts through background plasmas/gases present in the reactor chamber. HIPIB technologies, initially developed for inertial fusion driver systems, provide huge intensity pulses which meet the irradiation conditions expected in the first wall of LIF chambers and thus can be used for the validation of materials too.

Nanostructured tungsten as a first wall material for the future nuclear fusion reactors

The lack of materials able to withstand the severe radiation conditions (high thermal loads and atomistic damage) expected in fusion reactors is the actual bottle neck for fusion to become a reality. The main requisite for plasma facing materials (PFM) is to have excellent structural stability since severe cracking or mass loss would hamper their protection role which turns out to be unacceptable. Additional practical requirements for plasma facing materials are among others: (i) high thermal shock resistance, (ii) high thermal conductivity (iii) high melting point (iv) low physical and chemical sputtering, and (v) low tritium retention.

Results of the JET real-time disruption predictor in the ITER-like wall campaigns

The impact of disruptions in JET became even more important with the replacement of the previous Carbon Fiber Composite (CFC) wall with a more fragile full metal ITER-like wall (ILW). The development of robust disruption mitigation systems is crucial for JET (and also for ITER). Moreover, a reliable real-time (RT) disruption predictor is a pre-requisite to any mitigation method. The Advance Predictor Of DISruptions (APODIS) has been installed in the JET Real-Time Data Network (RTDN) for the RT recognition of disruptions. The predictor operates with the new ILW but it has been trained only with discharges belonging to campaigns with the CFC wall. 7 realtime signals are used to characterize the plasma status (disruptive or non-disruptive) at regular intervals of 1 ms. After the first 3 JET ILW campaigns (991 discharges), the success rate of the predictor is 98.36% (alarms are triggered in average 426 ms before the disruptions). The false alarm and missed alarm rates are 0.92% and 1.64%.

Fundamentos constructivos de las fortificaciones fronterizas entre las coronas de Castilla y Aragón de los siglos XII al XV en la actual provincia de Soria

La tesis doctoral desarrolla una investigación original, dentro del marco disciplinario de la historia de la construcción, sobre los fundamentos constructivos de las fortificaciones bajomedievales fronterizas entre las Coronas de Castilla y Aragón en la actual provincia de Soria. En el título de la tesis ya queda expresado el objeto fundamental y fundacional, así como el ámbito temporal —desde la reconquista del oriente soriano por parte de Alfonso I el Batallador a principios del siglo XII hasta la unificación de las coronas hispánicas en el siglo XV bajo el común mandato de los Reyes Católicos— y la extensión territorial que delimita la investigación: aquéllas comarcas castellanas lindantes con Aragón pertenecientes a la actual provincia de Soria. Durante este período bajomedieval se produjeron una serie de enfrentamientos fronterizos que obligó a fortificar la frontera y las vías de comunicación entre ambas coronas. La falta de estudios de conjunto de estas fortificaciones entendiéndolas como participantes en un sistema fortificado ha constituido la justificación de la investigación, que se realiza en varios niveles de análisis: territorial, histórico, arquitectónico, poliorcético y constructivo. Así mismo, se ha detectado cierta falta de rigor acompañada de inexactitudes en las consideraciones constructivas publicadas sobre algunas de las fortificaciones del ámbito de estudio, lo que ha provocado errores en su datación al no más haber elementos de corte artístico o estilístico que marquen indudablemente la pertenencia a una época. En la tesis se ponen en duda las dataciones tradicionalmente aceptadas planteando la hipótesis que da pie a la investigación: ante la falta de elementos artísticos o estilísticos en unos sobrios edificios eminentemente funcionales es posible establecer con suficiente aproximación la fecha de construcción en base a criterios constructivos una vez formada una clasificación cronotipológica de cada técnica constructiva. La hipótesis, por lo tanto, plantea un objetivo principal —el estudio de la razón constructiva del sistema fortificado fronterizo— desarrollado en una serie de objetivos específicos cuya consecución programa los sucesivos niveles de análisis: - Conocer y detallar los elementos históricos que originaron los enfrentamientos entre las Coronas de Castilla y Aragón y su desarrollo mediante herramientas historiográficas y analizar las características naturales del territorio en litigio mediante instrumentos cartográficos. - Conocer y analizar los tipos arquitectónicos y las tradiciones constructivas empleadas en las construcciones castrenses en el ámbito temporal en que se enmarca la investigación. - Localizar, documentar y seleccionar para su análisis las fortalezas y construcciones militares erigidas durante dichas luchas fronterizas en la actual provincia de Soria a través del trabajo de campo y métodos cartográficos y bibliográficos. - Realizar un estudio general sobre el sistema fortificado a escala territorial - Investigar la tipología arquitectónica, poliorcética y constructiva del conjunto de estas fortificaciones bajomedievales fronterizas. - Analizar los fundamentos constructivos de los casos de estudio seleccionados entre estas construcciones y caracterizarlas en cuanto al material, elementos, sistemas y procesos constructivos. - Ordenar la información histórica dispersa y corregir errores para hacer una base sobre la que establecer un discurso histórico de cada caso de estudio. - Comparar y relacionar las técnicas constructivas empleadas en estas fortalezas con los utilizados en el mismo ámbito temporal. - Difundir para su debate los resultados de la investigación por los foros científicos habituales. El método empleado combina los trabajos de gabinete con una intensa labor de campo, en la que se han documentado cincuenta fortificaciones y se han redactado sus correspondientes fichas de toma de datos. La recopilación de datos se ha incluido en una base de datos que incluye aspectos generales, tipológicos, constructivos y bibliográficos básicos del conjunto, a modo de inventario, de fortificaciones de la provincia. Las fortificaciones seleccionadas se agrupan según una clasificación tipológica y constructiva que marca las líneas de estudio posteriores. Se desarrolla un capítulo de antecedentes en el que se estudia la historia de la construcción fortificada medieval tanto en Europa como en España analizando la evolución de los tipos arquitectónicos y las múltiples influencias culturales que surcaron el Mediterráneo desde el Oriente cruzado e islámico al Poniente donde se desarrollaba la empresa reconquistadora que mantuvo en estado de guerra continuo a la Península Ibérica durante ochocientos años. El análisis del territorio como contenedor del hecho fortificado revela que hay una relación íntima entre la ubicación de las fortificaciones y las formas naturales que definen las vías de comunicación entre los valles del Duero, del Ebro y del Tajo. En efecto, el ámbito de estudio ha supuesto desde la Antigüedad un territorio de paso fundamental en la articulación de las comunicaciones en la Península Ibérica. Este carácter de paso más que de frontera explica las inquietudes y la preocupación por su control tanto por Roma como por el califato cordobés como por los reinos cristianos medievales. El análisis de los elementos históricos se complementa con el estudio detallado de los enfrentamientos fronterizos entre Castilla y Aragón así como los aspectos sociales y políticos que provocaron la fortificación como sistema de definición de la frontera y de organización espacial, jurisdiccional, social y administrativa del territorio. La arquitectura fortificada es esencialmente funcional: su cometido es la defensa. En este sentido, tras un estudio morfológico de los castillos seleccionados se realiza un extenso análisis poliorcético de sus elementos, investigando su origen y aplicación para servir también de parámetros de datación. Siendo el objeto inaugural de la tesis el estudio de los fundamentos constructivos, se explican los distintos materiales de construcción empleados y se agrupan las fábricas de las fortificaciones seleccionadas en dos grandes grupos constructivos: las fábricas aparejadas y las fábricas encofradas. Se han destacado y estudiado la evolución histórica y la tipología y mensiología constructiva de tres técnicas destacadas: el uso del ladrillo, la tapia de cal y canto o mampostería encofrada y la tapia de tierra. Para el estudio de la componente histórica y de la dimensión constructiva de cada técnica ha sido necesario documentar numerosos casos tanto en el ámbito de estudio como en la Península Ibérica con el fin de establecer grupos cronotipológicos constructivos entre los que poder ubicar las fábricas de estas técnicas presentes en el ámbito de estudio. Se ha observado una evolución dimensional de las fábricas de tapia que es más evidente en las hispanomusulmanas al modularse en codos pero que también se advierte significativamente en las cristianas bajomedievales. De cada una de las técnicas analizadas se ha seleccionado un caso de estudio singular y representativo. El castillo de Arcos de Jalón es un ejemplo significativo del empleo de la fábrica mixta de mampostería con verdugadas de ladrillo, así como las murallas de la ciudad fortificada de Peñalcázar lo es de la fábrica de mampostería encofrada y el castillo de Serón de Nágima constituye un caso característico y principal de la utilización de la tapia de tierra en la arquitectura militar bajomedieval. Cada uno de estos tres casos de estudios se examina bajo los mismos cuatro niveles anteriormente mencionados: territorial, histórico, arquitectónico y defensivo y constructivo. El sistemático método de estudio ha facilitado el orden en la investigación y la obtención de unos resultados y conclusiones que verifican la hipótesis y cumplen los objetivos marcados al comienzo. Se ha revisado la datación en la construcción de las fortificaciones analizadas mediante el estudio cronotipológico de sus fábricas, pudiendo trasladarse el método a otros sistemas fortificados. La tesis abre, finalmente, dos vías principales de investigación encaminadas a completar el estudio del sistema fortificado fronterizo bajomedieval en la raya oriental soriana de Castilla: la caracterización y datación por métodos físico-químicos de las muestras de piezas de madera de construcción que se conservan embebidas en las fábricas y la búsqueda documental y archivística que pueda revelar nuevos datos respecto a la fundación, reparación, venta o cualquier aspecto económico, legislativo, organizativo o administrativo relativo a las fortificaciones en documentos coetáneos. ABSTRACT The doctoral thesis develops an original research, held in the field of the Construction History, about the constructive reason of the frontier fortifications in the Late Middle Age between the Crowns of Castile and Aragón in the actual province of Soria, Spain. In the title is expressed the main objective, and also the temporal scope —from the reconquest in the 12th Century by Alfonso the First of Aragón to the unification under the common kingdom of the Catholic Kings— and the territorial extension that the research delimits: those Castilian regions in the border with Aragón in the actual province of Soria. During this period, a series of border wars were been, and this is the reason for the fortification of the border line and the main roads between both Crowns. The lack of studies of these fortifications as participants in a fortified system is the justification of the research. There is several analysis levels: territorial, historical, architectonic, defensive and constructive. Likewise, there is a lack of strictness and inaccuracy in the constructive items in the publications about several fortifications of this study field. This aspect has caused mistakes in the dating because there is neither artistic nor stylistic elements which determines a epoch. The traditionally accepted datings are challenged. An hypothesis is formulated: in the absence of artistic or stylistic elements in a sober and functional buildings is possible to date the time of construction with sufficiently approximation based on construction criteria once formed a cronotypologic classification of each building technique. The hypothesis, therefore, propose a main aim: the study of the constructive reason of the fortified border system. This aim is developed in a series of specifically targets whose achievement programs the analysis levels: - To know and to detail the historical elements which started the wars between Castile and Aragon and its development using historiographical tools, and to analyze the natural characteristic of the territory through cartographical tools. - To understand and to analyze the different architectural types and the building traditions employed in the military buildings in the time researched. - To locate, to document, and to select for their analysis the fortresses and military constructions erected during these border wars in the actual province of Soria through fieldwork and bibliographical and cartographical methods. - To conduct a general study on the fortified system in territorial scale. - To research the architectural, constructive and defensive typology of the system of these border late medieval fortifications. - To analyze the construction logic of the selected case studies and to characterize in the items of material, elements, systems and construction processes. - To sort scattered historical information and to correct mistakes to make a base by which to establish a historic speech of each case study. - To compare and to relate the construction techniques employed in these fortresses with those used in the same time range . - To spread for discussion the research results in the usual scientists forums. The method combines the destock work with an intense fieldwork. Fifty fortifications have been documented and it has written their corresponding data collection card. Data collection has been included in a database that includes general aspects, typological, constructive and basic bibliographical data, as an inventory of fortifications in the province. The selected fortifications are grouped according to a typological and constructive classification which lead the lines of the later study. There is a chapter for the antecedents in which the history of the medieval fortified construction in Europe and in Spain is studied by analyzing the evolution of architectural types and the many cultural influences along the opposite seasides of the Mediterranean Sea, from the Islamic and Crusader East to the Iberian Peninsula in where there were a long and continuous war during eight hundred years. The territory is analyzed as a container of fortifications. This analysis reveals that there is an intimate relationship between the location of the fortifications and the natural forms that define the communication roads between the Duero, Ebro and Tajo valleys. Indeed, the study area has been a cross-territory from ancient times more than a frontierterritory. This communication character explains the concerns about its control both by Rome and by the Muslims of Córdoba as medieval Christian kingdoms. The analysis of historical elements is supplemented by detailed study of border war between Castile and Aragon and the social and political issues that led to the fortification as border definition system and spatial, jurisdictional, social and administrative planning. The fortified architecture is essentially functional: it is responsible for defense. In this sense, after a morphological study of selected castles is performed an extensive analysis of its defensive elements, investigating its origin and application. This analisis serves for the definition of parameters for dating. The purpose of the thesis is the study of the constructive logic. First, various building materials are explained. Then, masonry is grouped into two major constructive groups: rigged masonry and formwork masonry. The historical evolution and the constructive typology and mensiology are studied for each one of the three main techniques: the use of brickwork, the mortar wall and rammed-earth. Many case studies have been documented along the Iberian Peninsula and also in the study area. As conclusion, there is a dimensional evolution of the rammed-earth walls. This evolution is more evident into the Muslim masonry than in the late medieval walls: the reason is the use of the cubit as module. From each of the techniques discussed, a singular and representative case of study has been selected. The castle of Arcos de Jalon is a significant example of mix masonry of stone and brick rows. The walled city of Peñalcázar is built with masonry formwork. Serón de Nágima castle, at last, is a typical and main case of the use of the rammedearth wall of late medieval military architecture. Each of these three case studies were examined under the same four analysis levels above mentioned: territorial, historical, architectural and defensive and constructive. The systematic method of study has facilitated the order in the research and the obtaining of results and conclusions that verify the hypotheses and achieve the research objectives. Dating of the fortifications construction has been revised by studying the cronotypological issues of its masonry. The method can be transferred to the study of other fortified systems. Finally, the thesis describes two main research new ways aimed at completing the study of the late medieval fortified border of Castile in the actual province of Soria. The first of them is the characterization and datig by physicochemical methods the sample pieces of wood construction preserved embedded in the masonry. The second research way is the investigation of the documents in archives that may reveal new information about the foundation, repair, sale or any aspect to economic, legal, organizational or administrative concerning fortifications in contemporary documents.

Seismic performance case study of bridge pile cap foundation

The purpose of this report is to build a model that represents, as best as possible, the seismic behavior of a pile cap bridge foundation by a nonlinear static (analysis) procedure. It will consist of a reproduction of a specimen already built in the laboratory. This model will carry out a pseudo static lateral and horizontal pushover test that will be applied onto the pile cap until the failure of the structure, the formation of a plastic hinge in the piles due to the horizontal deformation, occurs. The pushover test consists of increasing the horizontal load over the pile cap until the horizontal displacement wanted at the height of the pile cap is reached. The output of this model will be a Skeleton curve that will plot the lateral load (kN) over the displacement (m), so that the maximum movement the pile cap foundation can reach before its failure can be calculated. This failure will be achieved when the load at that specific shift is equal to 85% of the maximum. The pile cap foundation finite element model was based on pile cap built for a laboratory experiment already carried out by the Master student Deming Zhang at Tongji University. Two different pile caps were tested with a difference in height above the ground level. While one has 0:3m, the other rises 0:8m above the ground level. The computer model was calibrated using the experimental results. The pile cap foundation will be programmed in a finite element environment called OpenSees (Open System for Earthquake Engineering Simulation [28]). This environment is a free software developed by Berkeley University specialized, as it name says, in the study of earthquakes and its effects on structures. This specialization is the main reason why it is being used for building this model as it makes it possible to build any finite element model, and perform several analysis in order to get the results wanted. The development of OpenSees is sponsored by the Pacific Earthquake Engineering Research Center through the National Science Foundation engineering and education centers program. OpenSees uses Tcl language to program it, which is a language similar to C++.