918 resultados para Shaanxi earthquake
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In this paper, first we look back at the activities of the JMSDF in the Indian Ocean and the Gulf for the past 10-20 years from the view-point of contributions to security in the regions, and Japan's defence and diplomatic policies. In addition we would like to consider the situation that Japan has currently been placed in, or the primary factors of the change of power balance caused by China's foreign expansion and US gradual troop reductions, and economic conditions and energy supply problems after the earthquake disaster, as well as the returning of the LDP Administration. Each of these affects Japan's defence and diplomatic policies, and Japanese approach to Gulf countries is to be precisely understood in this context. For Japan, the importance of relationships with Gulf countries will surely increase in the foreseeable future. However the immediate addition of the JMSDF's force in the Indian Ocean and the Gulf Region is difficult. So Japan's role in regional security will probably be depending on the licensing of technology to India and Gulf countries, plus the construction of collaborative systems devoted to the training and support of highly proficient personnel. China will have a competitive relationship with Japan over access to the energy supply sources and the markets in Gulf countries, and it will be necessary to employ such systems for the purpose of international trust building and preventing of any free-ride.
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The traditional architecture of the centre of the city of Arequipa has been analyzed by comparing floor-plans of houses from the eighteenth and nineteenth centuries in order to explain the reasons behind the arrangement of their constructional elements and the evolution of said elements and floor-plans. The historic centre of Arequipa, a city located in the South of Perú, South America (Latitude 16°23' South, Longitude 71 °31' West), is based on a ground plan from 1540 that was set during the city's Spanish foundation. It was declared Patrimony of the Humanity by UNESCO. The manorial architecture is widely known for its decorated fronts and one-of-a-kind designs, but its differences with respect to the popular architecture are not based exclusively on decorative aspects. Peru's colonial period finished around 1825, but the barrel-vault, construction style continued in Arequipa through 1868, when an earthquake destroyed the city. Thereafter, the vaults were replaced by roofs made of rails, with cinders made out of the lava stone. The stately houses belonged to the founding families who settled around the main square on forty nine blocks that formed a square-grid, street layout. Also belonging to this category are the houses of landlords and traders from post-colonial times.
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The threat of impact or explosive loads is regrettably a scenario to be taken into account in the design of lifeline or critical civilian buildings. These are often made of concrete and not specifically designed for military threats. Numerical simulation of such cases may be undertaken with the aid of state of the art explicit dynamic codes, however several difficult challenges are inherent to such models: the material modeling for the concrete anisotropic failure, consideration of reinforcement bars and important structural details, adequate modeling of pressure waves from explosions in complex geometries, and efficient solution to models of complete buildings which can realistically assess failure modes. In this work we employ LS-Dyna for calculation, with Lagrangian finite elements and explicit time integration. Reinforced concrete may be represented in a fairly accurate fashion with recent models such as CSCM model [1] and segregated rebars constrained within the continuum mesh. However, such models cannot be realistically employed for complete models of large buildings, due to limitations of time and computer resources. The use of structural beam and shell elements for this purpose would be the obvious solution, with much lower computational cost. However, this modeling requires careful calibration in order to reproduce adequately the highly nonlinear response of structural concrete members, including bending with and without compression, cracking or plastic crushing, plastic deformation of reinforcement, erosion of vanished elements etc. The main objective of this work is to provide a strategy for modeling such scenarios based on structural elements, using available material models for structural elements [2] and techniques to include the reinforcement in a realistic way. These models are calibrated against fully three-dimensional models and shown to be accurate enough. At the same time they provide the basis for realistic simulation of impact and explosion on full-scale buildings
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We study the dynamic response of a wind turbine structure subjected to theoretical seismic motions, taking into account the rotational component of ground shaking. Models are generated for a shallow moderate crustal earthquake in the Madrid Region (Spain). Synthetic translational and rotational time histories are computed using the Discrete Wavenumber Method, assuming a point source and a horizontal layered earth structure. These are used to analyze the dynamic response of a wind turbine, represented by a simple finite element model. Von Mises stress values at different heights of the tower are used to study the dynamical structural response to a set of synthetic ground motion time histories
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Tras el devastador terremoto del 12 de enero de 2010 en Puerto Príncipe, Haití, las autoridades locales, numerosas ONGs y organismos nacionales e internacionales están trabajando en el desarrollo de estrategias para minimizar el elevado riesgo sísmico existente en el país. Para ello es necesario, en primer lugar, estimar dicho riesgo asociado a eventuales terremotos futuros que puedan producirse, evaluando el grado de pérdidas que podrían generar, para dimensionar la catástrofe y actuar en consecuencia, tanto en lo referente a medidas preventivas como a adopción de planes de emergencia. En ese sentido, este Trabajo Fin de Master aporta un análisis detallado del riesgo sísmico asociado a un futuro terremoto que podría producirse con probabilidad razonable, causando importantes daños en Puerto Príncipe. Se propone para ello una metodología de cálculo del riesgo adaptada a los condicionantes de la zona, con modelos calibrados empleando datos del sismo de 2010. Se ha desarrollado en el marco del proyecto de cooperación Sismo-Haití, financiado por la Universidad Politécnica de Madrid, que comenzó diez meses después del terremoto de 2010 como respuesta a una petición de ayuda del gobierno haitiano. El cálculo del riesgo requiere la consideración de dos inputs: la amenaza sísmica o movimiento esperado por el escenario definido (sismo de cierta magnitud y localización) y los elementos expuestos a esta amenaza (una clasificación del parque inmobiliario en diferentes tipologías constructivas, así como su vulnerabilidad). La vulnerabilidad de estas tipologías se describe por medio de funciones de daño: espectros de capacidad, que representan su comportamiento ante las fuerzas horizontales motivadas por los sismos, y curvas de fragilidad, que representan la probabilidad de que las estructuras sufran daños al alcanzar el máximo desplazamiento horizontal entre plantas debido a la mencionada fuerza horizontal. La metodología que se propone especifica determinadas pautas y criterios para estimar el movimiento, asignar la vulnerabilidad y evaluar el daño, cubriendo los tres estados del proceso. Por una parte, se consideran diferentes modelos de movimiento fuerte incluyendo el efecto local, y se identifican los que mejor ajustan a las observaciones de 2010. Por otra se clasifica el parque inmobiliario en diferentes tipologías constructivas, en base a la información extraída en una campaña de campo y utilizando además una base de datos aportada por el Ministerio de Obras Públicas de Haití. Ésta contiene información relevante de todos los edificios de la ciudad, resultando un total de 6 tipologías. Finalmente, para la estimación del daño se aplica el método capacidad-demanda implementado en el programa SELENA (Molina et al., 2010). En primer lugar, utilizado los datos de daño del terremoto de 2010, se ha calibrado el modelo propuesto de cálculo de riesgo sísmico: cuatro modelos de movimiento fuerte, tres modelos de tipo de suelo y un conjunto de funciones de daño. Finalmente, con el modelo calibrado, se ha simulado un escenario sísmico determinista correspondiente a un posible terremoto con epicentro próximo a Puerto Príncipe. Los resultados muestran que los daños estructurales serán considerables y podrán llevar a pérdidas económicas y humanas que causen un gran impacto en el país, lo que pone de manifiesto la alta vulnerabilidad estructural existente. Este resultado será facilitado a las autoridades locales, constituyendo una base sólida para toma de decisiones y adopción de políticas de prevención y mitigación del riesgo. Se recomienda dirigir esfuerzos hacia la reducción de la vulnerabilidad estructural - mediante refuerzo de edificios vulnerables y adopción de una normativa sismorresistente- y hacia el desarrollo de planes de emergencia. Abstract After the devastating 12 January 2010 earthquake that hit the city of Port-au-Prince, Haiti, strategies to minimize the high seismic risk are being developed by local authorities, NGOs, and national and international institutions. Two important tasks to reach this objective are, on the one hand, the evaluation of the seismic risk associated to possible future earthquakes in order to know the dimensions of the catastrophe; on the other hand, the design of preventive measures and emergency plans to minimize the consequences of such events. In this sense, this Master Thesis provides a detailed estimation of the damage that a possible future earthquake will cause in Port-au-Prince. A methodology to calculate the seismic risk is proposed, adapted to the study area conditions. This methodology has been calibrated using data from the 2010 earthquake. It has been conducted in the frame of the Sismo-Haiti cooperative project, supported by the Technical University of Madrid, which started ten months after the 2010 earthquake as an answer to an aid call of the Haitian government. The seismic risk calculation requires two inputs: the seismic hazard (expected ground motion due to a scenario earthquake given by magnitude and location) and the elements exposed to the hazard (classification of the building stock into building typologies, as well as their vulnerability). This vulnerability is described through the damage functions: capacity curves, which represent the structure performance against the horizontal forces caused by the seisms; and fragility curves, which represent the probability of damage as the structure reaches the maximum spectral displacement due to the horizontal force. The proposed methodology specifies certain guidelines and criteria to estimate the ground motion, assign the vulnerability, and evaluate the damage, covering the whole process. Firstly, different ground motion prediction equations including the local effect are considered, and the ones that have the best correlation with the observations of the 2010 earthquake, are identified. Secondly, the classification of building typologies is made by using the information collected during a field campaign, as well as a data base provided by the Ministry of Public Works of Haiti. This data base contains relevant information about all the buildings in the city, leading to a total of 6 different typologies. Finally, the damage is estimated using the capacity-spectrum method as implemented in the software SELENA (Molina et al., 2010). Data about the damage caused by the 2010 earthquake have been used to calibrate the proposed calculation model: different choices of ground motion relationships, soil models, and damage functions. Then, with the calibrated model, a deterministic scenario corresponding to an epicenter close to Port-au-Prince has been simulated. The results show high structural damage, and therefore, they point out the high structural vulnerability in the city. Besides, the economic and human losses associated to the damage would cause a great impact in the country. This result will be provided to the Haitian Government, constituting a scientific base for decision making and for the adoption of measures to prevent and mitigate the seismic risk. It is highly recommended to drive efforts towards the quality control of the new buildings -through reinforcement and construction according to a seismic code- and the development of emergency planning.
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• Central America: – Regional studies in Central America (Seismic Hazard). – El Salvador Fault Zone (ESFZ). – Aguacaliente‐Navarro Fault Zone (ANFZ), Central Valley of Costa Rica. – Haiti (seismic hazard) • Spain: – Regional‐Nacional studies of seismic hazards (applications to building codes, eurocode, emergency plans, etc.) – Betic range zone, south of Spain. – Ibero‐Maghrebi region (collision zone)
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1999 Seismic Hazard In Guatemala 2001 Post-Event Mision 2006 Resis Ii Project Norad 2007 Workshop Seismic Hazard 2010 Book Amenaza Sísmica En América Central 2011 Cooperation Haití, República Dominicana, Puerto Rico
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La Guadua (Guadua angustifolia Kunth) es una de las especies forestales más características de Colombia. Perteneciente a la familia del bambú, ésta planta nativa de Colombia usada en la construcción permite una reducción de costos, garantizados, entre otras ventajas, por sus propiedades físico-mecánicas de flexibilidad, resistencia, dureza, efecto climatizado y sismo resistencia. En el proyecto se plantea inicialmente un estudio de la Guadua como material estructural. Se estudiará su anatomía, sus propiedades físicas y mecánicas así como la normativa existente que rige su uso en construcción y por último se darán algunos ejemplos en los que se puede comprobar su uso en la actualidad. Posteriormente se procederá al desarrollo del proyecto cuya finalidad es el diseño de una estructura modular multifuncional que se necesita para llevarla a cabo en un proyecto de cooperación localizado en Neiva (Colombia). El proyecto incluirá todos los documentos necesarios para un trabajo de estas características: memoria, pliego de condiciones técnicas, presupuesto, planos, así como el Estudio de Seguridad y Salud Laboral. Como solución a las necesidades planteadas en el proyecto de cooperación, se realizará el diseño de dos estructuras modulares cuya finalidad sea las de uso como oficina y como almacén. Se aplicará para su cálculo el CTE cómo normativa de construcción, pero apoyándose en algunos parámetros en la NSR-10, estableciendo una comparativa posterior entre ambas normativas. Debido a la importancia de la acción sísmica en Colombia se comprobará la resistencia sísmica del módulo diseñado según el “Manual de Construcción, evaluación y rehabilitación sismo resistente de viviendas de mampostería” creado por la Asociación Colombiana de Ingeniería Sísmica. Basándose en este manual se definirán los tipos de uniones más favorables sísmicamente de los módulos con el diseño de una cercha auxiliar necesaria según el tipo de unión. ABSTRACT PROJECT: Structural applications of the guadua (Guadua angustifolia Kunth). Project of modular multifunctional structure in Colombia Guadua (Guadua angustifolia Kunth) is one of the forest species more characteristics of Colombia. Pertaining to the family of the bamboo, this one native plant of Colombia used in the construction allows a reduction of costs, guaranteed, among others advantages, by its physic mechanical properties of flexibility, resistance, hardness, climatic effect and earthquake resistance. The project initially considers a study of the Guadua as structural material. We will study its anatomy, its physical and mechanical properties as well as the existing norm that governs its use in construction and finally some examples will be provided in which its actual use can be verified. Later on, we will proceed with the development of the project which purpose is the design of a multifunctional modular structure required to in a project of cooperation located in Neiva (Colombia). The project will include all the necessary documents for a work of these characteristics: memory, technical specifications, budget, drawings, as well as the Security and Labor Health Study. In order to satisfy the needs raised in the cooperation project, we will undertake the design of two modular structures with the purpose to be used as office and warehouse. The construction normative CTE will be applied for its calculation, but some parameters will be based in the NSR-10, establishing a comparison between both norms. Due to the importance of the seismic action in Colombia, the seismic resistance of the module will be verified according to the “Manual of Construction, evaluation and rehabilitation resistant earthquake of rubblework houses” created by the Colombian Association of Seismic Engineering,. We will also use this Manual to define the types of unions more favorable from seismic point of view, designing the required auxiliary segments according to the type of union.
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Los terremotos constituyen una de las más importantes fuentes productoras de cargas dinámicas que actúan sobre las estructuras y sus cimentaciones. Cuando se produce un terremoto la energía liberada genera movimientos del terreno en forma de ondas sísmicas que pueden provocar asientos en las cimentaciones de los edificios, empujes sobre los muros de contención, vuelco de las estructuras y el suelo puede licuar perdiendo su capacidad de soporte. Los efectos de los terremotos en estructuras constituyen unos de los aspectos que involucran por su condición de interacción sueloestructura, disciplinas diversas como el Análisis Estructural, la Mecánica de Suelo y la Ingeniería Sísmica. Uno de los aspectos que han sido poco estudiados en el cálculo de estructuras sometidas a la acciones de los terremotos son los efectos del comportamiento no lineal del suelo y de los movimientos que pueden producirse bajo la acción de cargas sísmicas, tales como posibles despegues y deslizamientos. En esta Tesis se estudian primero los empujes sísmicos y posibles deslizamientos de muros de contención y se comparan las predicciones de distintos tipos de cálculos: métodos pseudo-estáticos como el de Mononobe-Okabe (1929) con la contribución de Whitman-Liao (1985), y formulaciones analíticas como la desarrollada por Veletsos y Younan (1994). En segundo lugar se estudia el efecto del comportamiento no lineal del terreno en las rigideces de una losa de cimentación superficial y circular, como la correspondiente a la chimenea de una Central Térmica o al edificio del reactor de una Central Nuclear, considerando su variación con frecuencia y con el nivel de cargas. Finalmente se estudian los posibles deslizamientos y separación de las losas de estas dos estructuras bajo la acción de terremotos, siguiendo la formulación propuesta por Wolf (1988). Para estos estudios se han desarrollado una serie de programas específicos (MUROSIS, VELETSOS, INTESES y SEPARSE) cuyos listados y detalles se incluyen en los Apéndices. En el capítulo 6 se incluyen las conclusiones resultantes de estos estudios y recomendaciones para futuras investigaciones. ABSTRACT Earthquakes constitute one of the most important sources of dynamic loads that acting on structures and foundations. When an earthquake occurs the liberated energy generates seismic waves that can give rise to structural vibrations, settlements of the foundations of buildings, pressures on retaining walls, and possible sliding, uplifting or even overturning of structures. The soil can also liquefy losing its capacity of support The study of the effects of earthquakes on structures involve the use of diverse disciplines such as Structural Analysis, Soil Mechanics and Earthquake Engineering. Some aspects that have been the subject of limited research in relation to the behavior of structures subjected to earthquakes are the effects of nonlinear soil behavior and geometric nonlinearities such as sliding and uplifting of foundations. This Thesis starts with the study of the seismic pressures and potential displacements of retaining walls comparing the predictions of two types of formulations and assessing their range of applicability and limitations: pseudo-static methods as proposed by Mononobe-Okabe (1929), with the contribution of Whitman-Liao (1985), and analytical formulations as the one developed by Veletsos and Younan (1994) for rigid walls. The Thesis deals next with the effects of nonlinear soil behavior on the dynamic stiffness of circular mat foundations like the chimney of a Thermal Power Station or the reactor building of a Nuclear Power Plant, as a function of frequency and level of forces. Finally the seismic response of these two structures accounting for the potential sliding and uplifting of the foundation under a given earthquake are studied, following an approach suggested by Wolf (1988). In order to carry out these studies a number of special purposes computer programs were developed (MUROSIS, VELETSOS, INTESES and SEPARSE). The listing and details of these programs are included in the appendices. The conclusions derived from these studies and recommendations for future work are presented in Chapter 6.
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El presente trabajo es un estudio teórico – experimental para la implementación de un edificio metálico de cuatro plantas con dispositivos disipadores de energía. Este estudio presenta una técnica para la generación de un registro sísmico artificial, que sea compatible con los espectros de diseño de las normas chilena y española. Este acelerograma se crea con una herramienta computacional denominada SIMQKE. La simulación de la estructura sometida al terremoto artificial se realizará en el programa de elementos finitos SAP200. El trabajo se encuentra dividido en cuatro capítulos, cuyos contenidos son los siguientes. En el capitulo uno, o estado del arte, se revisan las diferentes técnicas de aislamiento sísmico, se describe el dispositivo a utilizar, sus bases teóricas y formulación matemática, se revisan las normas NCh.2745 Of.2003 [12], NCSE-02 [18] y se presenta la técnica para la generación de un registro sintético compatible. El capítulo dos aborda el análisis experimental para un edificio real: una edificación de estructura metálica implementada con disipadores de energía metálicos y que será sometida a tres terremotos de diferente magnitud. El capítulo tres expone los resultados de los desplazamientos medidos para la estructura sin disipadores y con ellos, se presentan los porcentajes de disminución de desplazamientos relativos por planta y por tipo de estructura. Por último, el capítulo cuatro presenta las principales conclusiones y una breve discusión de los resultados. The present work is a theoretical and experimental study for the implementation of a fourstorey building with energy dissipating devices. This study presents a technique for generation an artificial seismic record, which is compatible with the design spectra Chilean and Spanish standards. This accelerogram is created with a computational tool called SIMQKE. The simulation of the structure subjected to artificial earthquake will take place in the finite element program SAP2000. This work is divided into four chapters whose contents are as follows. In chapter one, or state of the art, reviews the different seismic isolation techniques, describes the device used, theoretical and mathematical formulation, NCh2745 Of.2003 [12] and NCSE-02 [18] standards are checked, and presents the technique for generating a synthetic record compatible. Chapter two explains the experimental analysis to a real building: a building of steel structure implemented with metallic energy dissipators and will be submitted to three different earthquakes of magnitude. Chapter three presents the results of measured displacements for the structure without dissipators and with them, the percentages of decline relative displacements per plant and type of structure. Finally, chapter four presents the main conclusions and a brief discussion of the results.
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Este estudio aborda la recopilación de nuevas tendencias del diseño sismorresistente, enfocándose en la técnica del aislamiento de base, por ser la más efectiva, difundida y utilizada; y el análisis de las ventajas que puede tener una edificación que aplica dicha técnica, desde el punto de vista estructural y económico. Se elige la tipología más frecuente o común de edificios de hormigón armado propensos a ser aislados, que en este caso es un hospital, cuyo modelo empotrado se somete a varias normas sismorresistentes comparando principalmente fuerzas de cortante basal, y considerando la interacción suelo-estructura; para asistir a este cálculo se desarrolla un programa de elementos viga de 6 gdl por nodo en código Matlab. El modelo aislado incluye el análisis de tres combinaciones de tipos de aisladores HDR, LPR y FPS, alternando modelos lineales simplificados de 1 y 3 gdl por piso, evaluando diferencias de respuestas de la estructura, y procediendo a la elección de la combinación que de resultados más convenientes; para la modelación no lineal de cada sistema de aislamiento se utiliza el método explícito de diferencias centrales. Finalmente, se realiza un análisis comparativo de daños esperados en el caso de la ocurrencia del sismo de diseño, utilizando el método rápido y tomando como referencia el desplazamiento espectral del último piso; llegando a dar conclusiones y recomendaciones para el uso de sistemas de aislamiento. This study addresses the collection of new seismic design trends, focusing on base isolation technique, as the most effective and widely used, and the analysis of the advantages in buildings that apply this technique, from the structurally and economically point of view. Choosing the most common types of concrete buildings likely to be isolated, which in this case is a hospital, the fix model is subjected to various seismic codes mainly comparing base shear forces, and considering the soil-structure interaction; for this calculation attend a program of bars 6 dof per node is made in Matlab code. The isolated model includes analysis of three types of isolators combinations HDR, LPR and FPS, alternating simplified linear model of 1 and 3 dof per floor, evaluating differences in the response of the structure, and proceeding to the choice of the combination of results more convenient; for modeling nonlinear each insulation system, the explicit central difference method is used. Finally, a comparative analysis of expected damage in the case of the design earthquake, using a fast combined method and by reference to the spectral displacement of the top floor; reaching conclusions and give recommendations for the use of insulation systems.
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Under-deck cable-stayed bridges are very effective structural systems for which the strong contribution of the stay cables under live loading allows for the design of very slender decks for persistent and transient loading scenarios. Their behaviour when subjected to seismic excitation is investigated herein and a set of design criteria are presented that relate to the type and arrangement of bearings, the number and configuration of struts, and the transverse distribution of stay cables. The nonlinear behaviour of these bridges when subject to both near-field and far-field accelerograms has been thoroughly investigated through the use of incremental dynamic analyses. An intensity measure that reflects the pertinent contributions to response when several vibration modes are activated was proposed and is shown to be effective for the analysis of this structural type. The under-deck cable-stay system contributes in a very positive manner to reducing the response when the bridges are subject to very strong seismic excitation. For such scenarios, the reduction in the stiffness of the deck because of crack formation, when prestressed concrete decks are used, mobilises the cable system and enhances the overall performance of the system. Sets of natural accelerograms that are compliant with the prescriptions of Eurocode 8 were also applied to propose a set of design criteria for this bridge type in areas prone to earthquakes. Particular attention is given to outlining the optimal strategies for the deployment of bearings