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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.
1121

Disaster Waste Management: a systems approach

Brown, Charlotte Olivia January 2012 (has links)
Depending on their nature and severity, disasters can create large volumes of debris and waste. Waste volumes from a single event can be the equivalent of many times the annual waste generation rate of the affected community. These volumes can overwhelm existing solid waste management facilities and personnel. Mismanagement of disaster waste can affect both the response and long term recovery of a disaster affected area. Previous research into disaster waste management has been either context specific or event specific, making it difficult to transfer lessons from one disaster event to another. The aim of this research is to develop a systems understanding of disaster waste management and in turn develop context- and disaster-transferrable decision-making guidance for emergency and waste managers. To research this complex and multi-disciplinary problem, a multi-hazard, multi-context, multi-case study approach was adopted. The research focussed on five major disaster events: 2011 Christchurch earthquake, 2009 Victorian Bushfires, 2009 Samoan tsunami, 2009 L’Aquila earthquake and 2005 Hurricane Katrina. The first stage of the analysis involved the development of a set of ‘disaster & disaster waste’ impact indicators. The indicators demonstrate a method by which disaster managers, planners and researchers can simplify the very large spectra of possible disaster impacts, into some key decision-drivers which will likely influence post-disaster management requirements. The second stage of the research was to develop a set of criteria to represent the desirable environmental, economic, social and recovery effects of a successful disaster waste management system. These criteria were used to assess the effectiveness of the disaster waste management approaches for the case studies. The third stage of the research was the cross-case analysis. Six main elements of disaster waste management systems were identified and analysed. These were: strategic management, funding mechanisms, operational management, environmental and human health risk management, and legislation and regulation. Within each of these system elements, key decision-making guidance (linked to the ‘disaster & disaster waste’ indicators) and management principles were developed. The ‘disaster & disaster waste’ impact indicators, the effects assessment criteria and management principles have all been developed so that they can be practically applied to disaster waste management planning and response in the future.
1122

The Performance of House Foundations in the Canterbury Earthquakes

Henderson, Duncan Robert Keall January 2013 (has links)
The Canterbury Earthquakes of 2010-2011, in particular the 4th September 2010 Darfield earthquake and the 22nd February 2011 Christchurch earthquake, produced severe and widespread liquefaction in Christchurch and surrounding areas. The scale of the liquefaction was unprecedented, and caused extensive damage to a variety of man-made structures, including residential houses. Around 20,000 residential houses suffered serious damage as a direct result of the effects of liquefaction, and this resulted in approximately 7000 houses in the worst-hit areas being abandoned. Despite the good performance of light timber-framed houses under the inertial loads of the earthquake, these structures could not withstand the large loads and deformations associated with liquefaction, resulting in significant damage. The key structural component of houses subjected to liquefaction effects was found to be their foundations, as these are in direct contact with the ground. The performance of house foundations directly influenced the performance of the structure as a whole. Because of this, and due to the lack of research in this area, it was decided to investigate the performance of houses and in particular their foundations when subjected to the effects of liquefaction. The data from the inspections of approximately 500 houses conducted by a University of Canterbury summer research team following the 4th September 2010 earthquake in the worst-hit areas of Christchurch were analysed to determine the general performance of residential houses when subjected to high liquefaction loads. This was followed by the detailed inspection of around 170 houses with four different foundation types common to Christchurch and New Zealand: Concrete perimeter with short piers constructed to NZS3604, concrete slab-on-grade also to NZS3604, RibRaft slabs designed by Firth Industries and driven pile foundations. With a focus on foundations, floor levels and slopes were measured, and the damage to all areas of the house and property were recorded. Seven invasive inspections were also conducted on houses being demolished, to examine in more detail the deformation modes and the causes of damage in severely affected houses. The simplified modelling of concrete perimeter sections subjected to a variety of liquefaction-related scenarios was also performed, to examine the comparative performance of foundations built in different periods, and the loads generated under various bearing loss and lateral spreading cases. It was found that the level of foundation damage is directly related to the level of liquefaction experienced, and that foundation damage and liquefaction severity in turn influence the performance of the superstructure. Concrete perimeter foundations were found to have performed most poorly, suffering high local floor slopes and being likely to require foundation repairs even when liquefaction was low enough that no surface ejecta was seen. This was due to their weak, flexible foundation structure, which cannot withstand liquefaction loads without deforming. The vulnerability of concrete perimeter foundations was confirmed through modelling. Slab-on-grade foundations performed better, and were unlikely to require repairs at low levels of liquefaction. Ribraft and piled foundations performed the best, with repairs unlikely up to moderate levels of liquefaction. However, all foundation types were susceptible to significant damage at higher levels of liquefaction, with maximum differential settlements of 474mm, 202mm, 182mm and 250mm found for concrete perimeter, slab-on-grade, ribraft and piled foundations respectively when subjected to significant lateral spreading, the most severe loading scenario caused by liquefaction. It was found through the analysis of the data that the type of exterior wall cladding, either heavy or light, and the number of storeys, did not affect the performance of foundations. This was also shown through modelling for concrete perimeter foundations, and is due to the increased foundation strengths provided for heavily cladded and two-storey houses. Heavy roof claddings were found to increase the demands on foundations, worsening their performance. Pre-1930 concrete perimeter foundations were also found to be very vulnerable to damage under liquefaction loads, due to their weak and brittle construction.
1123

The integration of earthquake engineering resources

Lamata Martinez, Ignacio January 2014 (has links)
Earthquake engineering is increasingly focusing on large international collaborations to address complex problems. Recent computing advances have greatly contributed to the way scientific collaborations are conducted, where web-based solutions are an emerging trend to manage and present results to the scientific community and the general public. However, collaborations in earthquake engineering lack a common interoperability framework, resulting in tedious and complex processes to integrate results, which cannot be efficiently used by third-party institutions. The work described in this thesis applies novel computing techniques to enable the interoperability of earthquake engineering resources, by integrating data, distributed simulation services and laboratory facilities. This integration focuses on distributed approaches rather than centralised solutions, and has been materialised in a platform called Celestina, that supports the integration of hazard mitigation resources. The prototype of Celestina has been implemented and validated within the context of two of the current largest earthquake engineering networks, the SERIES network in Europe and the NEES network in the USA. It has been divided into three sub-systems to address different problems: (i) Celestina Data, to develop best methods to define, store, integrate and share earthquake engineering experimental data. Celestina Data uses a novel approach based on Semantic Web technologies, and it has accomplished the first data integration between earthquake engineering institutions from the United States and Europe by means of a formalised infrastructure. (ii) Celestina Tools, to research applications that can be implemented on top of the data integration, in order to provide a practical benefit for the end user. (iii) Celestina Simulations, to create the most efficient methods to integrate distributed testing software and to support the planning, definition and execution of the experimental workflow from a high-level perspective. Celestina Simulations has been implemented and validated by conducting distributed simulations between the Universities of Oxford and Kassel. Such validation has demonstrated the feasibility to conduct both flexible, general-purpose and high performance simulations under the framework. Celestina has enabled global analysis of data requirements for the whole community, the definition of global policies for data authorship, curation and preservation, more efficient use of efforts and funding, more accurate decision support systems and more efficient sharing and evaluation of data results in scientific articles.
1124

Evaluation des risques sismiques par des modèles markoviens cachés et semi-markoviens cachés et de l'estimation de la statistique / Seismic hazard assessment through hidden Markov and semi-Markov modeling and statistical estimation

Votsi, Irène 17 January 2013 (has links)
Le premier chapitre présente les axes principaux de recherche ainsi que les problèmes traités dans cette thèse. Plus précisément, il expose une synthèse sur le sujet, en y donnant les propriétés essentielles pour la bonne compréhension de cette étude, accompagnée des références bibliographiques les plus importantes. Il présente également les motivations de ce travail en précisant les contributions originales dans ce domaine. Le deuxième chapitre est composé d’une recherche originale sur l’estimation du risque sismique, dans la zone du nord de la mer Egée (Grèce), en faisant usage de la théorie des processus semi-markoviens à temps continue. Il propose des estimateurs des mesures importantes qui caractérisent les processus semi-markoviens, et fournit une modélisation dela prévision de l’instant de réalisation d’un séisme fort ainsi que la probabilité et la grandeur qui lui sont associées. Les chapitres 3 et 4 comprennent une première tentative de modélisation du processus de génération des séismes au moyen de l’application d’un temps discret des modèles cachés markoviens et semi-markoviens, respectivement. Une méthode d’estimation non paramétrique est appliquée, qui permet de révéler des caractéristiques fondamentales du processus de génération des séismes, difficiles à détecter autrement. Des quantités importantes concernant les niveaux des tensions sont estimées au moyen des modèles proposés. Le chapitre 5 décrit les résultats originaux du présent travail à la théorie des processus stochastiques, c’est- à-dire l’étude et l’estimation du « Intensité du temps d’entrée en temps discret (DTIHT) » pour la première fois dans des chaînes semi-markoviennes et des chaînes de renouvellement markoviennes cachées. Une relation est proposée pour le calcul du DTIHT et un nouvel estimateur est présenté dans chacun de ces cas. De plus, les propriétés asymptotiques des estimateurs proposés sont obtenues, à savoir, la convergence et la normalité asymptotique. Le chapitre 6 procède ensuite à une étude de comparaison entre le modèle markovien caché et le modèle semi-markovien caché dans un milieu markovien et semi-markovien en vue de rechercher d’éventuelles différences dans leur comportement stochastique, déterminé à partir de la matrice de transition de la chaîne de Markov (modèle markovien caché) et de la matrice de transition de la chaîne de Markov immergée (modèle semi-markovien caché). Les résultats originaux concernent le cas général où les distributions sont considérées comme distributions des temps de séjour ainsi que le cas particulier des modèles qui sont applique´s dans les chapitres précédents où les temps de séjour sont estimés de manière non-paramétrique. L’importance de ces différences est spécifiée à l’aide du calcul de la valeur moyenne et de la variance du nombre de sauts de la chaîne de Markov (modèle markovien caché) ou de la chaîne de Markov immergée (modèle semi-markovien caché) pour arriver dans un état donné, pour la première fois. Enfin, le chapitre 7 donne des conclusions générales en soulignant les points les plus marquants et des perspectives pour développements futurs. / The first chapter describes the definition of the subject under study, the current state of science in this area and the objectives. In the second chapter, continuous-time semi-Markov models are studied and applied in order to contribute to seismic hazard assessment in Northern Aegean Sea (Greece). Expressions for different important indicators of the semi- Markov process are obtained, providing forecasting results about the time, the space and the magnitude of the ensuing strong earthquake. Chapters 3 and 4 describe a first attempt to model earthquake occurrence by means of discrete-time hidden Markov models (HMMs) and hidden semi-Markov models (HSMMs), respectively. A nonparametric estimation method is followed by means of which, insights into features of the earthquake process are provided which are hard to detect otherwise. Important indicators concerning the levels of the stress field are estimated by means of the suggested HMM and HSMM. Chapter 5 includes our main contribution to the theory of stochastic processes, the investigation and the estimation of the discrete-time intensity of the hitting time (DTIHT) for the first time referring to semi-Markov chains (SMCs) and hidden Markov renewal chains (HMRCs). A simple formula is presented for the evaluation of the DTIHT along with its statistical estimator for both SMCs and HMRCs. In addition, the asymptotic properties of the estimators are proved, including strong consistency and asymptotic normality. In chapter 6, a comparison between HMMs and HSMMs in a Markov and a semi-Markov framework is given in order to highlight possible differences in their stochastic behavior partially governed by their transition probability matrices. Basic results are presented in the general case where specific distributions are assumed for sojourn times as well as in the special case concerning the models applied in the previous chapters, where the sojourn time distributions are estimated non-parametrically. The impact of the differences is observed through the calculation of the mean value and the variance of the number of steps that the Markov chain (HMM case) and the EMC (HSMM case) need to make for visiting for the first time a particular state. Finally, Chapter 7 presents concluding remarks, perspectives and future work.
1125

Socio-cultural characteristics and policies vis-à-vis seismic risk reduction throught post-quake rural reconstruction : a case study of Azad Jammu and Kashmir, Pakistan / Les caractéristiques socioculturelles et les politiques vis-à-vis de réduction du risque sismique par la reconstruction post-séisme dans les zones rurales : région de l'étude, Azad Jammu et Cachemire

Abidi, Syeda Raaeha Tuz Zahra 20 December 2013 (has links)
Cette thèse a pour objectif d’explorer la relation entre les caractéristiques socio-culturelles et les politiques de reconstruction post-séisme dans les zones rurales de Azad Jammu et du Cachemire, au Pakistan. L’objet principal est d’examiner les pratiques architecturales traditionnelles : dhajji-dewari et la composition sociale de la communanuté pendant et après la reconstruction. Différents processus sont analysés: comment les aspects socio-culturels des sociétés rurales sont affectés par les politiques de reconstruction? Comment les politiques sont touchées par les aspects socio-culturels des commmunautés? Comment la combinaison des deux influence le processus final?Ce travail de thèse part du constat que 80% des 600 000 bâtiments endommagés ou détruits lors du séisme du 8 octobre 2005 au Cachemire, étaient des maisons rurales provisoires (Katcha). Il s’agit d’examiner jusqu’où le Programme de Reconstruction de Logement Rural (RHRP) qui a concerné quelque 100 000 maisons dhajji, a réduit ou augmenté la vulnérabilité de la zone pour l'avenir. Ce programme a été initié à partir de l’expérience de précédents programmes de reconstruction post-tremblements de terre, qui ont été d’une grande utilité pour les experts. Il restait à analyser les erreurs commises ou répétées par les différents acteurs pendant les phases d’élaboration, de validation, de mise en œuvre, et de suivi des politiques de reconstruction. Les principaux résultats de la thèse couvrent trois thèmes relatifs aux différentes étapes de la reconstruction : la durabilité de la reconstruction ; la réduction de la vulnérabilité de la reconstruction ; les résultats qui n’entrent pas dans les catégories “durabilité” et “vulnérabilité” selon les experts du Cachemire rural. La satisfaction des communautés est l’indicateur principal permettant d’évaluer les principaux résultats. L'étude conclut que la non-prise en compte des aspects socioculturels des communautés pendant la reconstruction peut augmenter la vulnérabilité du scénario de post-reconstruction. Le suivi du programme de reconstruction consiste à évaluer les tendances liées aux maisons en construction. En présentant par des illustrations les détails architecturaux de ces maisons reconstruites, l’écart avec les recommandations est évalué. Après que quelques années, les populations oublient les impacts du séisme et leurs besoins immédiats dictent leurs priorités de décision. Il est suggéré qu'à la fin du programme de reconstruction, la présence des autorités dans la zone reconstruite permette d’assister les populations dans leurs besoins actuels et futurs, et de contrôler le développement des constructions non conformes. / This thesis is aimed at exploring the relation of socio-cultural characteristics and policies with post-quake reconstruction of rural areas of Azad Jammu & Kashmir, Pakistan. The primary concern of the study is limited to examine the traditional architectural practice ; dhajji-dewari and social composition of the community during and after reconstruction. It is analyzed that how the socio-cultural aspects of rural communities are affected by the policies, how policies are affected by the socio-cultural aspects of the community and how both of these can influence the final product. The thesis was rooted in the fact that 80% of the 600,000 damaged/destroyed buildings during 8th October, 2005 Kashmir earthquake were rural temporary (Katcha) houses. It was hence to be investigated that how far the Rural Housing Reconstruction Program (RHRP) has reduced (or increased) the vulnerability of the area for future. The impact of any policy launched during this program was not limited to few housing units rather more than 0.1 million dhajji houses could be affected through this. The rural Kashmir reconstruction was commenced with the in-hand knowledge of several previous post-quake reconstruction programs and was appreciated widely by experts. It was yet to be explored that which mistakes were committed/repeated by the stakeholders during policy making, delivery, implementation and post implementation phases. Covering the phases of policy making, delivery and implementation, the major findings of the thesis are categorized into three sections ; the sustainability generating aspects of reconstruction, vulnerability enhancing dimensions of reconstruction, and, those outcomes of reconstruction which are not yet categorized under ”sustainability” or ”vulnerability” by the experts focusing particularly rural Kashmir. Community satisfaction is given primary focus to rate different outcomes.The study concludes that ignoring socio-cultural aspects of the community during reconstruction may lead to vulnerability in post-reconstruction scenario. Considering the post implementation phase, the current trends are observed by examining under-construction houses. By pictorially presenting the architectural details of these houses it is examined that deviations from guidelines are in practice. People start forgetting the disaster impacts after few years and their immediate needs drive their decision priorities. It is suggested that after reconstruction program ends up, some authorities must be present in the reconstructed area to guide people for their current requirements and future needs and also to control the spread of non compliant construction.
1126

Commande de systèmes d'isolation antisismique mixte / Control of mixed seismic isolation systems

Teodorescu, Catalin Stefan 30 October 2013 (has links)
Nous nous intéressons aux méthodes de contrôle de vibrations de modèles réduits de structures à n degrés de liberté, sismiquement isolées au niveau de la base par des systèmes d'isolation mixte.Le mouvement provoqué par une sollicitation sismique horizontale a lieu dans le plan vertical.Nous avons construit un problème de contrôle semi-actif de systèmes incertains soumis à des perturbations inconnues, mais bornées. Dans le langage de l'automatique, il s'agit d'un problème d'atténuation de perturbations.Le résultat principal de cette thèse porte sur la construction d'une version modifiée des résultats de Leitmann et de ses collaborateurs sur la stabilisation de systèmes non linéaires incertains. Le théorème proposé repose sur une loi de commande par retour d'état qui assure en boucle fermée les propriétés de "uniform boundedness" et "uniform ultimate boundedness".En particulier, il peut être appliqué à la résolution de problèmes de contrôle semi-actif, qui sont actuellement traités en génie parasismique.L'objectif du contrôle est d'améliorer le comportement (i.e. la réponse) de structures isolées pour faire face aux perturbations externes, c'est-à-dire les séismes. Plusieurs points différencient notre problème de la majorité que l'on trouve dans la littérature: (i) on ne s'intéresse pas seulement à la protection de la structure isolée, mais aussi aux équipements situés à l'intérieur de la structure, et (ii) au lieu d'utiliser des indicateurs de performance habituels exprimés en termes de déplacement relatif de la base versus des accélérations absolues des planchers, nous utilisons uniquement le spectre de plancher en pseudo-accélération, comme il a été proposé dans des travaux précédents par Politopoulos et Pham. Ce travail est une tentative d'utiliser explicitement les spectres de plancher comme critère de performance.Concernant la procédure d'application, plusieurs étapes intermédiaires ont été détaillées:(i) modélisation de signaux sismiques;(ii) réglage des paramètres de la loi de commande utilisant la théorie des vibrations;(iii) validation et test du comportement en boucle fermée à travers des simulations numériques: pour des raisons de simplicité, on se limite au cas n=2.Cette procédure peut être utilisée sur des structures en industrie nucléaire, mais aussi en génie civil.D'autres sujets traités incluent une tentative d'utiliser les outils temps-fréquence, et en particulier la distribution de Wigner-Ville, pour la synthèse de lois de commande, en espérant pouvoir mieux contrôler les composants transitoires des signaux de perturbation (les entrées) et des variables d'état (les sorties). / Vibration attenuation control designs are proposed for reduced plant models consisting of n-degree-of-freedom base seismically-isolated structures (i.e., a specific type of earthquake-resistant design), modeled by uncertain nonlinear systems and subjected to one-dimensional horizontal ground acceleration (i.e. the earthquake signal), treated as unknown disturbance but assumed to be bounded.In control systems literature, this is a perturbation attenuation problem.The main result of this PhD is the development of a modified version of Leitmann and co-authors' classical result on the stabilization of uncertain nonlinear systems. The proposed theorem consists of a bounded nonlinear feedback control law that is capable of ensuring uniform boundedness and uniform ultimate boundedness in closed-loop. In particular, it can be applied to solving semi-active control design problems, which are currently dealt with in earthquake engineering.The control objective is to improve the behavior (i.e. response) of mixed base-isolated structures to external disturbance, namely earthquakes. What differentiates our problem from the majority to be found in the literature is that: (i) attention is being paid to the protection of equipment placed inside the structure an not only to the structure itself; (ii) instead of using regular performance indicators expressed in terms of relative base displacement versus floors accelerations, we use solely the pseudo-acceleration floor response spectra, as it was proposed in previous recent works by Politopoulos and Pham.Actually, this work is an attempt to explicitly use floor response spectra as performance criterion.Concerning the application procedure, some of the topics that were detailed are:(i) modeling of earthquake signals;(ii) tuning of control law parameters based on vibration theory;(iii) validation and testing of the closed-loop behavior using numerical simulations: for simplicity reasons, we take n=2.This procedure can be used on structures of both nuclear industry as well as civil engineering.Other topics include an attempt to using time-frequency concepts and in particular the Wigner-Ville distribution to the control law design procedure, in order to better control transitory components of both perturbation (the input) and state variables signals (the output).
1127

自然災害、遷移選擇與社會環境影響─以雲林縣古坑鄉為例 / Natural Disasters, Migration Decisions, and Social Environmental Impact:A Case Study In Gukeng, Yunlin

鍾宛君, Chung, Wan Chun Unknown Date (has links)
本研究以經歷過921大地震以及多次土石流災害的雲林縣古坑鄉為個案,透過參與觀察法、質性訪談以及文獻檔案分析的方式,以了解當那些受到環境劇變的人們在經歷自然災害後,如何在有選的情況下做出遷移與否的決策,而哪些社會因素會在決策過程中影響人們的決定及行動。 本研究的重要發現包括以下幾點:第一,在自然災害發生後,多數的居民會選擇留下,這是基於本身的災害識覺排除了立即性、短時間內的生命威脅。同時,大部分的居民也會因為在地性的資源(如社會關係、在地知識、與在地的不動產)較多,而傾向選擇留在原地。同時,有一些社經弱勢家庭會因為非在地性資源的缺乏,也使他們不得不做出留下來的選擇。從生命史的觀點,本研究發現這些遷移決策往往是鑲嵌在長期累積的地方經驗與生活脈絡中的。第二,家庭的遷移往往是家庭成員整體的決定,或考量家庭整體需要後做出的決定。不同的家庭可能採取不同的方式來完成他們在地重建或者是遷移的目標。第三,個人和家庭的慣習往往在選擇的傾向或行動的方式中成為核心。多數人希望能在自然災害發生後恢復既有的生活慣習,但慣習的維持不僅在於個人能力,也與他所在環境中是否有足夠的社會支持有關。當社區中的社會安全網可以提供足夠的支持時,個人與家庭的慣習則得以被維持,而社區社會安全網又和地方產業型態具有緊密關聯。以觀光為主要發展的草嶺村,和在921大地震後轉型為觀光農業的華山村就是兩個極佳的對比案例。研究資料也顯示當地居民改變社會環境的可能,證明了人不是單向地受到社會環境的影響,也可以反向影響社會環境。 / This study aims at understanding how people make migration decisions after drastic environmental changes brought by natural disasters and exploring the social factors influencing these decisions. Gukeng was chosen as a case for this study due to its encounters of the Chichi earthquake and several landslides. The study utilizes qualitative research methods and collects field data, mainly through participant observation, in-depth interviewing techniques and text analysis. The main findings of this study are summarized as follows. First, most residents tend to stay after natural disasters, and such choice is based on their hazard perception that excludes immediate and short-term threats to their lives. The majority of residents prefer to stay due to more local resources(including social relationships, local knowledge, and ownership of real estate property). Those families in lower social-economic status also tend to stay for the lack of non-local resources. From the perspective of life history, these decisions are embedded in local contexts contructed and experiences accumulated throughout the years. Second, family’s migration decision is usually made by all family members or based on the needs of all members. Different families may use different ways to reach their goals of migration or rebuilding on the same ground. Third, the habitus of individuals and families often become the core element in the modes of choice and action. Most people want to be able to recover their habitus after the natural disasters. However, the maintenance of the habitus is based not only on personal capacity, but also on the social support drawn from the his environment. People can maintain their habitus when the local community safety net can provide enough support, and the local community safety net is highly related to the development of local industries. The comparative study of Caoling Villege and Huashan Villege provides an illustrative example, in which the former is based on tourism and the latter was transformed into eco-tourism and tourist agriculture after the Chichi earthquake. The findings also show the possibility of people changing the environment, proving the mutual influence between individuals and the environment.
1128

Seismic Response Of Geosynthetic Reinforced Soil Wall Models Using Shaking Table Tests

Adapa, Murali Krishna 02 1900 (has links)
Use of soil retaining walls for roads, embankments and bridges is increasing with time and reinforced soil retaining walls are found to be very efficient even under critical conditions compared to unreinforced walls. They offer competitive solutions to earth retaining problems associated with less space and more loads posed by tremendous growth in infrastructure, in addition to the advantages in ease and cost of construction compared to conventional retaining wall systems. The study of seismic performance of reinforced soil retaining walls is receiving much attention in the light of lessons learned from past failures of conventional retaining walls. Laboratory model studies on these walls under controlled seismic loading conditions help to understand better how these walls actually behave during earthquakes. The objective of the present study is to investigate the seismic response of geosynthetic reinforced soil wall models through shaking table tests. To achieve this, wrap faced and rigid faced reinforced soil retaining walls of size 750 × 500 mm in plan and 600 mm height are built in rigid and flexible containers and tested under controlled dynamic conditions using a uni-axial shaking table. The effects of frequency and acceleration of the base motion, surcharge pressure on the crest, number of reinforcing layers, container boundary, wall structure and reinforcement layout on the seismic performance of the retaining walls are studied through systematic series of shaking table tests. Results are analyzed to understand the effect of each of the considered parameters on the face displacements, acceleration amplifications and soil pressures on facing at different elevations of the walls. A numerical model is developed to simulate the shaking table tests on wrap faced reinforced soil walls using a computer program FLAC (Fast Lagrangian Analysis of Continua). The experimental data are used to validate the numerical model and parametric studies are carried out on 6 m height full-scale wall using this model. Thus, the study deals with the shaking table tests, dynamic response of reinforced walls and their numerical simulation. The thesis presents detailed description of various features and various parts of the shaking table facility along with the instrumentation and model containers. Methodology adopted for the construction of reinforced soil model walls and testing procedures are briefly described. Scaling and stability issues related to the model wall size and reinforcement strength are also discussed. From the study, it is observed that the displacements are decreasing with the increase in relative density of backfill, increase in surcharge pressure and increase in number of reinforcing layers; In general, accelerations are amplified to the most at the top of the wall; Behaviour of model walls is sensitive to model container boundary. The frequency content is very important parameter affecting the model response. Further, it is noticed that the face displacements are significantly affected by all of the above parameters, while the accelerations are less sensitive to reinforcement parameters. Even very low strength geonet and geotextile are able to reduce the displacements by 75% compared to unreinforced wall. The strain levels in the reinforcing elements are observed to be very low, in the order of ±150 micro strains. A random dynamic event is also used in one of the model tests and the resulted accelerations and displacements are presented. Numerical parametric studies provided important insight into the behaviour of wrap faced walls under various seismic loading conditions and variation in physical parameters.
1129

"A ver quem passa". O Rossio. Proceso social y dinámicas interactivas en una plaza del centro de Lisboa

Malet Calvo, Daniel 31 October 2011 (has links)
Investigación histórica y etnográfica en el espacio simbólico y ceremonial más emblemático de la ciudad de Lisboa: O Rossio. Tratamos de agotar sus elementos físicos, relacionales y simbólicos, siguiendo varias escalas de análisis, en una interpretación general de la sociedad lisboeta. 1-(“Presentación del Objeto de Estudio”): se introducen las fuentes teóricas generales que atraviesan el texto, centradas en la antropología urbana y en la problemática del espacio en tanto que producción social. Asimismo, desarrollamos una breve historia de la Praça do Rossio para proporcionar la medida de su importancia y las funciones que desempeña en el marco de la ciudad. 2-(“Culturas de la Miseria, Miserias de la Cultura”): Empezamos con un primer ensayo etnográfico sobre las técnicas interactivas y las dramaturgias de la pobreza en Rossio. A modo de estudio comparativo, sigue una crítica a las políticas de governabilidad urbana en Barcelona, especialmente beligerantes ante la visibilidad de la miseria. Cerramos el bloque repasando las controversias relativas a la construcción identitaria portuguesa y su “excesso de diagnóstico”, donde creemos localizar el núcleo discursivo de una cierta familiaridad con la subjetivación de la pobreza. 3-(“Los Espacios y sus hombres”): Un pequeño capítulo sobre las metodologías y los protocolos etnográficos utilizados, da paso al análisis socioespacial “delimitado” de la Praça do Rossio. Se emprende aquí una revisión espacial de las 12 áreas en que dividimos la plaza, con el fin de conocer sus atributos en profundidad, descubriendo las relaciones que se establecen con su entorno constituyente -visible e invisible-, y dando lugar a las primeras reflexiones sobre el papel de Rossio en tanto que dispositivo sociourbano modular. Los mapas y diagramas ayudan a la comprensión microsocial de las trayectorias, las apropiaciones y las logicas socioespaciales que tienen lugar en la plaza. Profusamente conocido ya el espacio y sus derivaciones, en los bloques cuarto y quinto se tratan las profundas relaciones de la plaza con la evolución de la ciudad, tomando el terremoto de 1755 como acontecimiento sociourbanístico central. 4-(“La fisura pombalina I: la imaginación patrimonial”): Presentamos una breve etnografía del comercio informal en Rossio, descubriendo su estrecha vinculación con procesos de patrimonialización contemporáneos, especialmente la folclorización de Alfama y el proceso político de control sobre las festas de Lisboa. En él descubrimos que los erasmus de Alfama reproducen el imaginario pintoresquista de los estudios olisipográficos, en procesos que se operan a través de la sublimación del comercio informal. Las variaciones históricas en la adscripción topológica de las prácticas de mercadeo, así como las particularidades de su versión patrimonial reificada, nos conducen a la cuestión del terremoto, cuando en la Rossio del comercio informal tenga lugar la reconfiguración forzada de la ciudad entera. 5-(“La fisura pombalina II: la deriva urbana”): Nos centramos en las funciones morfológicas y simbólicas de Rossio en tanto que pieza articuladora del urbanismo lisboeta en general: siguiendo la pista anterior, ahondamos en el significado último de la intervención del Marqués después del seísmo de 1755. Un estudio de caso sobre la apropiación lusoafricana en una esquina de Rossio, nos permite profundizar en las consecuencias sociomorfológicas del terremoto: la “fisura pombalina” conduce, mediante dos “movimientos” simultáneos, a la bipolarización urbanística actual. Finalmente, analizaremos varios procesos recientes de capitalización en el centro de la ciudad, reconociendo asimismo el papel de diferentes actores sociales en la intervención urbana. ¿Sigue la Praça do Rossio conservando aquella inercia que la caracteriza más allá de “brechas” y “fisuras”?, ¿cuál es su papel en la articulación sociourbana de la ciudad?, ¿sigue siendo O Rossio un rossio, es decir, un espacio de apropiación colectiva marcado por la confluencia de las energías societarias? / The present historical and ethnographic research is focused on the most emblematic space in Lisbon's downtown, Praça do Rossio. The comprehension of its historical function and cultural significance is explored by the following arguments and study cases: 1- The state of art on urban anthropology and an introduction to the social and political history of this emplacement. 2- An essay about beggar's performance and poverty visibility on Lisbon's streets, regarded as a discursive effect based on Portuguese identity construction, in contrast to Barcelona's anti-poor governance strategies. 3- An in-depth description of every single material element and detail from square's morphological composition, that lead us to consider Rossio both as a relationship playground and as historical emplacement. Besides, this chapter includes maps and diagrams showing the complexity of appropriations and circulations, as well as ethnographic insights and cultural issues. With all morphological details displayed, and with a large cultural square's acknowledgment, chapters 4 and 5 introduce the core of interpretation, allowing us to comprehend the urban and social function of Rossio through the most critical urban event in Lisbon's history: The 1755 earthquake. First, in chapter 4, informal economy and its liturgical dramatizations on Santos Populares city feasts -stated by olisipography's nineteenth-century discourses- are analyzed as an heritagization process. Rossio was the heart of the historical street-vendor practices, symbolized in current hegemonic city representations. Secondly, in chapter 5 the daily Portuguese-Africans meetings on Rossio Largo's corner are analyzed and considered as a symbol of the preservation of square's communicative and political functions. Summarizing the urban history of the city -and the social characterization, problems and representations of different neighborhoods-, Rossio is found to be the center of the politico-cultural and socio-morphological phenomena which is called “pombaline's fissure”: the symbolic and material displacement caused by 1755 urban disaster and its later reconstruction, that reorganizes the axis between the bourgeois and the popular city. The theoretical and methodological approach of urban and social anthropology, as well as all this data collection, allow us to argue that Rossio performs a function as an urban hinge, articulating the city's sociospatial bipolarization and its symbolic representations.
1130

Katastrofal rapportering : En kritisk diskursanalys av svenska dagstidningars rapportering om jordbävningen i Haiti respektive översvämningen i Pakistan 2010

Andersson, Lisette, Lundin, Kajsa January 2011 (has links)
This study deals with the distinct difference in media attention the earthquake-disaster in Haiti and the flood-disaster in Pakistan got in 2010. There may be many reasons to this divergence, but this study focuses on how news articles can create compassion.    This study, with its critical perspective, examines how two daily papers in Sweden portray the suffering of the victims of the catastrophes in Haiti and Pakistan, and create compassion for them. Furthermore it asks the question who benefits from the newspaper’s description of human suffering in the third world.    The result shows that the manner of which Swedish daily newspapers report from the catastrophe in Haiti creates an emotional involvement, which most likely leads to compassion. Furthermore it shows potential to lead the readers to identify with the suffering people in Haiti.    The Swedish daily newspapers report of the catastrophe in Pakistan on the other hand, does not involve the reader on an emotional level, but gives them the role of a spectator. However the result also indicates that the distance between the victim and the reader is reducing. In that remark the report have potential to create compassion for the victims in Pakistan, although it is more likely that this does not occur.    In conclusion the study shows that the Swedish daily newspapers report of the catastrophes in Haiti and Pakistan is embedded in an ideology, which reproduces a global hierarchy of suffering by reproducing the construction of an Us and Them. In addition this study reveals a social conception of the West as more worthy compassion than the third world, and therefore the Swedish daily newspapers report of the catastrophes reproduces the West’s dominance and power in the society.

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