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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Measuring Low Fault Strain Rate with Synthetic Aperture Radar: Application to the Pacific-North America Plate Boundary

Gourmelen, Noel 28 October 2009 (has links)
I use Synthetic Aperture Radar Interferometry (InSAR) to study the present deformation in the Western Basin and Range and Basin and Range - Sierra Nevada transition. I process 350 SAR data over 190·103 km2 for the period 1992 to 2002. Both stacking and time series processing were applied to produce precise (mm/yr) and high-resolution velocity map for the area. Two new processing techniques have been developed. The first technique solves for the long wavelength ambiguities of the InSAR derived velocity map that arise due to uncertainty in the orbital parameter of the satellite. The technique assimilates continuous GPS data into the InSAR time-series processing. The second technique extracts the horizontal and vertical components of the deformation field from two adjacent radar tracks. I applied stacking to study the transient deformation across the Central Nevada Seismic Belt and interseismic strain accumulation across the Eastern California Shear Zone. I show that the current deformation across the Central Nevada Seismic Belt can be explained by a combination of inter-seismic, post-seismic and anthropogenic deformation. The Post-Seismic deformation is associated with visco-elastic relaxation of the Earth's mantle in response to a centennial earthquake sequence of five ~M7 earthquakes along the Central Nevada Seismic Belt. The anthropogenic deformation is a response of the bedrock to water withdrawal in support of mining activity. A more evolved time-series approach that solves for orbital errors is applied across the Eastern California Shear Zone. The study shows that the Hunter Mountain - Panamint Valley fault system accommodates ~5 mm/yr, a faster rate than geological averages. The region of strain accumulation is a narrow band of ~10 km centered on the Hunter mountain fault, and indicates a very shallow locking depth in agreement with an active low angle normal fault system.
12

RELIABILITY AND RISK ASSESSMENT OF NETWORKED URBAN INFRASTRUCTURE SYSTEMS UNDER NATURAL HAZARDS

Rokneddin, Keivan 16 September 2013 (has links)
Modern societies increasingly depend on the reliable functioning of urban infrastructure systems in the aftermath of natural disasters such as hurricane and earthquake events. Apart from a sizable capital for maintenance and expansion, the reliable performance of infrastructure systems under extreme hazards also requires strategic planning and effective resource assignment. Hence, efficient system reliability and risk assessment methods are needed to provide insights to system stakeholders to understand infrastructure performance under different hazard scenarios and accordingly make informed decisions in response to them. Moreover, efficient assignment of limited financial and human resources for maintenance and retrofit actions requires new methods to identify critical system components under extreme events. Infrastructure systems such as highway bridge networks are spatially distributed systems with many linked components. Therefore, network models describing them as mathematical graphs with nodes and links naturally apply to study their performance. Owing to their complex topology, general system reliability methods are ineffective to evaluate the reliability of large infrastructure systems. This research develops computationally efficient methods such as a modified Markov Chain Monte Carlo simulations algorithm for network reliability, and proposes a network reliability framework (BRAN: Bridge Reliability Assessment in Networks) that is applicable to large and complex highway bridge systems. Since the response of system components to hazard scenario events are often correlated, the BRAN framework enables accounting for correlated component failure probabilities stemming from different correlation sources. Failure correlations from non-hazard sources are particularly emphasized, as they potentially have a significant impact on network reliability estimates, and yet they have often been ignored or only partially considered in the literature of infrastructure system reliability. The developed network reliability framework is also used for probabilistic risk assessment, where network reliability is assigned as the network performance metric. Risk analysis studies may require prohibitively large number of simulations for large and complex infrastructure systems, as they involve evaluating the network reliability for multiple hazard scenarios. This thesis addresses this challenge by developing network surrogate models by statistical learning tools such as random forests. The surrogate models can replace network reliability simulations in a risk analysis framework, and significantly reduce computation times. Therefore, the proposed approach provides an alternative to the established methods to enhance the computational efficiency of risk assessments, by developing a surrogate model of the complex system at hand rather than reducing the number of analyzed hazard scenarios by either hazard consistent scenario generation or importance sampling. Nevertheless, the application of surrogate models can be combined with scenario reduction methods to improve even further the analysis efficiency. To address the problem of prioritizing system components for maintenance and retrofit actions, two advanced metrics are developed in this research to rank the criticality of system components. Both developed metrics combine system component fragilities with the topological characteristics of the network, and provide rankings which are either conditioned on specific hazard scenarios or probabilistic, based on the preference of infrastructure system stakeholders. Nevertheless, they both offer enhanced efficiency and practical applicability compared to the existing methods. The developed frameworks for network reliability evaluation, risk assessment, and component prioritization are intended to address important gaps in the state-of-the-art management and planning for infrastructure systems under natural hazards. Their application can enhance public safety by informing the decision making process for expansion, maintenance, and retrofit actions for infrastructure systems.
13

Forecasting earthquake losses in port systems

Burden, Lindsay Ivey 20 February 2012 (has links)
Ports play a critical role in transportation infrastructure, but are vulnerable to seismic hazards. Downtime and reduced throughput from seismic damage in ports results in significant business interruption losses for port stakeholders. Current risk management practices only focus on the effect of seismic hazards on individual port structures. However, damage and downtime of these structures has a significant impact on the overall port system's ship handling operations and the regional, national, and even international economic impacts that result from extended earthquake-induced disruption of a major container port. Managing risks from system-wide disruptions resulting from earthquake damage has been studied as a central element of a Grand Challenge project sponsored by the National Science Foundation Network for Earthquake Engineering Simulation (NEES) program. The following thesis presents the concepts and methods developed for the seismic risk management of a port-wide system of berths. In particular the thesis discusses the framework used to calculated port losses: the use of spatially correlated ground motion intensity measures to estimate damage to pile-supported marginal wharves and container cranes of various configurations via fragility relationships developed by project team members, repair costs and downtimes subsequently determined via repair models for both types of structures, and the impact on cargo handling operations calculated via logistical models of the port system. Results are expressed in the form of loss exceedance curves than include both repair/replacement costs and business interruption losses. The thesis also discusses how the results from such an analysis might be used by port decision makers to make more informed decisions in design, retrofit, operational, and other seismic risk management options.
14

GIS based assessment of seismic risk for the Christchurch CBD and Mount Pleasant, New Zealand

Singh, Bina Aruna January 2006 (has links)
This research employs a deterministic seismic risk assessment methodology to assess the potential damage and loss at meshblock level in the Christchurch CBD and Mount Pleasant primarily due to building damage caused by earthquake ground shaking. Expected losses in terms of dollar value and casualties are calculated for two earthquake scenarios. Findings are based on: (1) data describing the earthquake ground shaking and microzonation effects; (2) an inventory of buildings by value, floor area, replacement value, occupancy and age; (3) damage ratios defining the performance of buildings as a function of earthquake intensity; (4) daytime and night-time population distribution data and (5) casualty functions defining casualty risk as a function of building damage. A GIS serves as a platform for collecting, storing and analyzing the original and the derived data. It also allows for easy display of input and output data, providing a critical functionality for communication of outcomes. The results of this study suggest that economic losses due to building damage in the Christchurch CBD and Mount Pleasant will possibly be in the order of $5.6 and $35.3 million in a magnitude 8.0 Alpine fault earthquake and a magnitude 7.0 Ashley fault earthquake respectively. Damage to non-residential buildings constitutes the vast majority of the economic loss. Casualty numbers are expected to be between 0 and 10.
15

Vibrations ambiantes, contenu spectral et dommages sismiques : nouvelle approche adaptée à l’échelle urbaine. Application à Beyrouth / Ambient vibrations, spectral content and seismic damages : new approach adapted to the urban scale. Application on Beirut

Salameh, Christelle 21 June 2016 (has links)
Il a été observé maintes fois dans les enquêtes post-sismiques que les structures ayant des fréquences similaires à celles du sol de fondation présentent des dommages beaucoup plus importants (Caracas 1967, Mexique 1985, Pujili, Equateur 1996; L'Aquila 2009). Cette observation de bon sens n'est cependant que très peu, ou de façon très indirecte, prise en compte d'une part dans les réglementations parasismiques (échelle du bâtiment), et d'autre part dans les études de risque et de scénario à l'échelle urbaine. On assiste ainsi souvent à un niveau de précision incohérent entre les études d'aléa, qui sont maintenant à même de cartographier de manière fiable les fréquences de sol, les possibilités actuelles en matière d'analyse du comportement dynamique des bâtiments, et les cartes de vulnérabilité et de risque finales. Une analyse numérique complète pour étudier l'effet de coïncidence entre les fréquences du sol et du bâtiment est effectuée. Un ensemble de 887 profils de sol réalistes est couplé avec un total de 141 oscillateurs élastoplastiques à un degré de liberté, et leurs réponses combinées (non linéaires) sont calculées à la fois pour un comportement de sol linéaire et non-linéaire, pour un grand nombre (60) de signaux d'entrée avec différents niveaux de PGA et contenu fréquentiel. Les dommages associés sont quantifiés sur la base du déplacement maximal comparé à la fois par rapport aux déplacements élastiques et ultimes, selon les recommandations du projet européen RISK-UE (Lagomarsino et Giovinazzi, 2006), et par rapports aux dommages obtenus dans le cas d’un bâtiment similaire situé sur le substratum rocheux. La corrélation entre les incréments de dommages entre sol et rocher et un certain nombre de paramètres simples mécaniques et de chargement est ensuite analysée en utilisant une approche de réseau neuronal. Les résultats soulignent le rôle clé joué par le rapport de fréquence bâtiment / sol, même lorsque le sol et la bâtiment se comportent de manière non linéaire; d'autres paramètres importants sont le niveau de PGA, le contraste d’impédance sol/rocher et la ductilité du bâtiment. Une enquête numérique spécifique basée sur la simulation du bruit ambiant pour l'ensemble des 887 profils indique également que l'impact du contraste d’impédance sol/rocher peut être cohéremment remplacée en utilisant l'amplitude du rapport H/V. Aussi l'effet de coïncidence apparaît comme une observation importante, non seulement dans la réponse de l'analyse des sites linéaires, mais aussi dans la réponse d'un site non-linéaire: en dépit d'un niveau important de non-linéarité atteint la coïncidence spectrale se produit, mais à un rapport de fréquence décalé vers des valeurs inférieures. La méthode élaborée permet une mise en œuvre très facile, en utilisant des mesures de vibrations ambiantes, tant au niveau du sol et à l'intérieur des bâtiments. Un exemple d'application très illustratif est représenté pour la ville de Beyrouth (Liban). / It has been observed repeatedly in post-seismic investigations that structures having frequencies close to foundation soil frequencies exhibit significantly heavier damages (Caracas 1967, Mexico 1985, Pujili, Ecuador 1996; L’Aquila 2009). However, these observations are generally not taken directly into account neither in present-day seismic regulations (small scale), nor at large-scale seismic risk analysis. We thus encounter frequently an incoherent precision level between hazard studies that are capable of reliably mapping the ground frequency, the actual possibilities of analyzing the dynamic behavior of the building, and the final vulnerability and risk maps. A comprehensive numerical analysis to investigate the effect of coincidence between soil and building frequencies is performed. A total of 887 realistic soil profiles are coupled with a set of 141 elastoplastic oscillators with a single degree of freedom and their combined (non-linear) response are computed both for linear and non-linear soil behavior, for a large number (60) of input signals of various PGA levels and frequency contents. The associated damage is quantified on the basis of the maximum displacement as compared to both yield and ultimate post-elastic displacements, according to the RISK-UE European project recommendations (Lagomarsino and Giovinazzi, 2006), and compared with the damage obtained in the case of a similar building located on bedrock. The correlation between this soil/rock damage increment and a number of simplified mechanical and loading parameters is then analyzed using a neural network approach. The results emphasize the key role played by the building/soil frequency ratio even when both soil and building behave non-linearly; other important parameters are the PGA level, the soil/rock impedance contrast and the building ductility. A specific numerical investigation based on simulation of ambient noise for the whole set of 887 profiles also indicates that the impact of soil/rock impedance contrast may be satisfactory replaced using the amplitude of H/V ratio. Moreover the effect of coincidence appears to be an important observation not only in the linear site analysis response but also in the nonlinear site response: in spite of a large nonlinearity level reached spectral coincidence occurs, however at a shifted frequency ratio towards lower values. The elaborated method allows a very easy implementation, using ambient vibration measurements both at ground level and within buildings. A very illustrative example application is shown for the city of Beirut (Lebanon).
16

On the Seismic Design of Structures with Tilting Located within a Seismic Region

Valenzuela-Beltrán, Federico, Ruiz, Sonia, Reyes-Salazar, Alfredo, Gaxiola-Camacho, J. 07 November 2017 (has links)
A reliability-based criterion to estimate strength amplification factors for buildings with asymmetric yielding located within a seismic region presenting different soil conditions is proposed and applied. The approach involves the calculation of the mean annual rate of exceedance of structural demands of systems with different levels of asymmetric yielding. Two simplified mathematical expressions are developed considering different soil conditions of the valley of Mexico. The mathematical expressions depend on the ductility of the structural systems, their level of asymmetric yielding, their fundamental vibration period and the dominant period of the soil. In addition, the proposed expressions are compared with that recommended by the current Mexico City Building Code (MCBC). Since the expressions are developed with the help of simplified structural systems, the validity of such expressions is corroborated by comparing the expected ductility demand of multi-degree of freedom (MDOF) structural systems with respect to that of their equivalent simplified systems. Both structural representations are associated with a given annual rate of exceedance value of an engineering demand parameter. The expressions proposed in this study will be incorporated in the new version of the MCBC.
17

Análisis del riesgo sísmico en edificaciones de albañilería mediante fichas de evaluación sistematizadas en una plataforma geoespacial en el sector 19, 20, 21 y 22, Distrito Chorrillos

Arrellano Herrera, Frank Lorenzo, Cadillo Villón, José Luis January 2015 (has links)
En el presente trabajo de investigación tiene como objetivo sistematizar la información sobre las características de edificaciones de albañilería en una plataforma geoespacial, basándonos de las aplicaciones de una función de vulnerabilidad (centro histórico Chiclayo) para el análisis de la vulnerabilidad y posteriormente evaluar el riesgo sísmico. Las edificaciones de albañilería confinada en los AA.HH, en específico de los sectores de estudio. Son viviendas que se construyen sin la supervisión de un especialista (ingenio civil), donde las viviendas son construidas generalmente por los propios pobladores o un maestro de obra de la zona, quienes desconocen las mínimas características del Reglamento Nacional de Edificaciones. Teniendo este escenario se ha realizo el análisis bajo once (11) parámetros para poder determinar la vulnerabilidad y el riesgo sísmico. Donde la característica principal del problema es, que se tiene como escenario las autoconstrucciones en las edificaciones de albañilería, donde esta situación pone en peligro a gran parte de la ciudadanía y la población por falta de conocimiento al momento de realizar dichas construcciones. El método a emplear en la investigación es de Benedetti y Petrini (método Italiano) estima un índice de vulnerabilidad calculado en función de las características de la estructura que más influyen en su comportamiento sísmico, y lo relaciona con un índice de daño, que a su vez depende de la acción del movimiento sísmico. El diseño de la Investigación es, No experimental, Transversal y Descriptivo los resultados que se obtuvo son edificaciones con vulnerabilidad de baja, moderada y severo. Para esta investigación de tubo tamaño de la población (manzanas) = 191, donde la muestra a utilizar es (n = 128) manzanas a evaluar en le los sectores 19, 20, 21, y 22 de distrito de chorrillos. In the present research aims to systematize information on the characteristics of masonry buildings in a geospatial platform based applications built-in vulnerability (historic center Chiclayo) for vulnerability analysis and subsequently evaluate the seismic risk. Confined masonry buildings in AA.HH in specific fields of study. These are homes that are built without the supervision of a specialist (Civil Engineering), where homes are generally built by villagers themselves or foreman of the area who know the minimum requirements of the National Building Regulations. Given this scenario analysis has been conducted on eleven (11) parameters to determine the vulnerability and seismic risk. The method used in research is of Benedetti and Petrini (Italian method) estimates a vulnerability index calculated according to the structure characteristics that influence their seismic behavior, and links it to an index of damage, which in turn depends on the action of earthquake. The research design is not experimental, transversal and descriptive the results obtained are vulnerable buildings with low, moderate and severe. Nationwide studies of seismic vulnerability of masonry buildings are rare, because there is a lack of knowledge of the general population how to follow procedures (construction process) in the construction of such buildings, where this can help mitigate the problem before a seismic event with destructive effects and the lack of alternative solutions increases the risk before a seismic event.
18

Admissible height and urban density of buildings for the Prospective Management of Seismic Risk in residential areas

Herrera, Fabiola, Mamani, Flaby, Arana, Victor 30 September 2020 (has links)
El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / This research proposes limit values of height and population density of buildings for a Prospective Management of Seismic Risk in residential areas. The analysis of an efficient evacuation of buildings to the street or refuge area was carried out, evaluating human behavior with models based on the agent, the influence of buildings and the urban parameters of the city with three-dimensional models (BIM) for a severe seismic scenario. The present article establishes that the maximum permissible height of buildings projected in a residential avenue is directly related to the width of the available refuge zone to guarantee the correct evacuation of said zone during a severe seismic event. In addition, an evaluation of a real existing scenario is made in a section of a residential avenue.
19

Regional Structural Investigation and Its Application on Seismic Risk Management for Groups of Traditional Wooden Buildings in Important Preservation Districts / 重要伝統的建造物群保存地区における木造建物群の構造調査と地震防災対策への応用

Jiao, Jian 24 March 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18261号 / 工博第3853号 / 新制||工||1591(附属図書館) / 31119 / 京都大学大学院工学研究科建築学専攻 / (主査)教授 林 康裕, 教授 吹田 啓一郎, 教授 神吉 紀世子 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
20

Measuring the Resilience of Transportation Networks Subject to Seismic Risk

Furtado, Mark N 18 March 2015 (has links)
Transportation networks are critical to the function of modern society but they are vulnerable to extreme events such as earthquakes. Damaged bridges can cost millions of dollars to repair and congestion and detours due to bridge closures leads to indirect costs that are even greater than the cost of repair of damaged bridges. A resilient network however should be able to limit the damage caused by earthquakes and recover in a timely fashion. Resilience of networks has been studying in length from a conceptual standpoint but as quantitative measure, the field has been lacking. This study sets forth to quantify resilience based on a set of performance measures and mapping them to the four properties of resilience: robustness, redundancy, resourcefulness and rapidity. The thesis ties in concepts from risk analysis that helps determine expected damage levels and connects those concepts to a resilience framework to better understand how a network responds and recovers after an earthquake. Also explored are methods to decrease repair time in order to limit the indirect costs due to network downtime as well as an overview of pre-event methods of improving resilience with a novel method of selecting bridges for retrofit while minimizing direct and indirect losses.

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