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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.
1001

The effects of earthquake excitations on reticulated domes

Uliana, David A. 14 November 2012 (has links)
Comparisons were made on the behavior of two full-sized reticulated domes subjected to uniform static loads only and uniform static loads with earthquake excitations. Space truss elements were used in the dome models. The stiffness matrix of the space truss element allows for the nonlinear strain-displacement behavior and the stress-strain behavior of the material is modeled with a bilinear approximation. The nonlinear solution technique is the Newton-Raphson method while the direct integration technique is the Newmark- Beta method. The joint displacements for the static and the dynamic analyses were compared for both domes along with the axial stresses in all members. The percentage increases in the axial stresses of the dynamic analyses as compared to those of the static analyses were determined. The reticulated domes used in the study were found to bet capable of withstanding the earthquake excitations when subjected to various uniform loads without failure. / Master of Science
1002

The impacts of the Canterbury earthquakes on educational inequalities and achievement in Christchurch secondary schools

Connolly, Maria Josephine January 2013 (has links)
During 2010 and 2011, major earthquakes caused widespread damage and the deaths of 185 people in the city of Christchurch. Damaged school buildings resulted in state intervention which required amendment of the Education Act of 1989, and the development of ‘site sharing agreements’ in undamaged schools to cater for the needs of students whose schools had closed. An effective plan was also developed for student assessment through establishing an earthquake impaired derived grade process. Previous research into traditional explanations of educational inequalities in the United Kingdom, the United States of America, and New Zealand were reviewed through various processes within three educational inputs: the student, the school and the state. Research into the impacts of urban natural disasters on education and education inequalities found literature on post disaster education systems but nothing could be found that included performance data. The impacts of the Canterbury earthquakes on educational inequalities and achievement were analysed over 2009-2012. The baseline year was 2009, the year before the first earthquake, while 2012 is seen as the recovery year as no schools closed due to seismic events and there was no state intervention into the education of the region. National Certificate of Educational Achievement (NCEA) results levels 1-3 from thirty-four secondary schools in the greater Christchurch region were graphed and analysed. Regression analysis indicates; in 2009, educational inequalities existed with a strong positive relationship between a school’s decile rating and NCEA achievement. When schools were grouped into decile rankings (1-10) and their 2010 NCEA levels 1-3 results were compared with the previous year, the percentage of change indicates an overall lower NCEA achievement in 2010 across all deciles, but particularly in lower decile schools. By contrast, when 2011 NCEA results were compared with those of 2009, as a percentage of change, lower decile schools fared better. Non site sharing schools also achieved higher results than site sharing schools. State interventions, had however contributed towards student’s achieving national examinations and entry to university in 2011. When NCEA results for 2012 were compared to 2009 educational inequalities still exist, however in 2012 the positive relationship between decile rating and achievement is marginally weaker than in 2009. Human ethics approval was required to survey one Christchurch secondary school community of students (aged between 12 and 18), teachers and staff, parents and caregivers during October 2011. Participation was voluntary and without incentives, 154 completed questionnaires were received. The Canterbury earthquakes and aftershocks changed the lives of the research participants. This school community was displaced to another school due to the Christchurch earthquake on 22 February 2011. Research results are grouped under four geographical perspectives; spatial impacts, socio-economic impacts, displacement, and health and wellbeing. Further research possibilities include researching the lag effects from the Canterbury earthquakes on school age children.
1003

Experimental and numerical studies of masonry wall panels and timber frames of low-rise structures under seismic loadings in Indonesia

Susila, Gede Adi January 2014 (has links)
Indonesia is a developing country that suffers from earthquakes and windstorms and where at least 60% of houses are non-engineered structures, built by unskilled workers using masonry and timber. The non-engineered housing units developed in urban region are also vulnerable to seismic hazard due to the use of low quality of material and constructions method. Those structures are not resistant to extreme lateral loads or ground movement and their failure during an earthquake or storm can lead to significant loss of life. This thesis is concerned with the structural performance of Indonesian low-rise buildings made of masonry and timber under lateral seismic load. The research presented includes a survey of forms of building structure and experimental, analytical and numerical work to predict the behaviour of masonry wall and traditional timber frame buildings. Experimental testing of both masonry and timber have been carried out in Indonesia to establish the quality of materials and to provide material properties for numerical simulations. The experimental study found that the strength of Indonesia-Bali clay brick masonry are below the minimum standard required for masonry structures built in seismic regions, being at least 50% lower than the requirement specified in British Standard and Eurocode-6 (BS EN 1996-1-1:2005). In contrast, Indonesian timber materials meet the strength classes specified in British Standard/Eurocode- 5 (BS EN 338:2009) in the range of strength grade D35-40 and C35).Structural tests under monotonic and cyclic loading have been conducted on building components in Indonesia, to determine the load-displacement capacity of local hand-made masonry wall panels and timber frames in order to: (1) evaluate the performance of masonry and timber frame structure, (2) investigate the dynamic behaviour of both structures, (3) observe the effect of in-plane stiffness and ductility level, and (4) examine the anchoring joint at the base of timber frame that resists the overturning moment. From these tests, the structural ductility was found to be less than two which is below the requirement of the relevant guidelines from the Federal Emergency Management Agency, USA (FEMA-306). It was also observed that the lateral stiffness of masonry wall is much higher than the equivalent timber frame of the same height and length. The experimental value of stiffness of the masonry wall panel was found to be one-twelfth of the recommended values given in FEMA-356 and the Canadian Building code. The masonry wall provides relatively low displacement compared to the large displacement of the timber frame at the full capacity level of lateral load, with structural framing members of the latter remaining intact. The weak point of the timber frame is the mechanical joint and the capacity of slip joint governs the lateral load capacity of the whole frame. Detailed numerical models of the experimental specimens were setup in Abaqus using three-dimensional solid elements. Cohesive elements were used to simulate the mortar behaviour, exhibiting cracking and the associated physical separation of the elements. Appropriate contact definitions were used where relevant, especially for the timber frame joints. A range of available material plasticity models were reviewed: Drucker-Prager, Crystalline Plasticity, and Cohesive Damage model. It was found that the combination of Crystalline Plasticity model for the brick unit and timber, and the Cohesive Damage model for the mortar is capable of simulating the experimental load-displacement behaviour fairly accurately. The validated numerical models have been used to (1) predict the lateral load capacity, (2) determine the cracking load and patterns, (3) carry out a detailed parametric study by changing the geometric and material properties different to the experimental specimens. The numerical models were used to assess different strengthening measures such as using bamboo as reinforcement in the masonry walls for a complete single storey, and a two-storey houses including openings for doors and windows. The traditional footing of the timber structures was analysed using Abaqus and was found to be an excellent base isolation system which partly explains the survival of those structures in the past earthquakes. The experimental and numerical results have finally been used to develop a design guideline for new construction as well as recommendations for retrofitting of existing structures for improved performance under seismic lateral load.
1004

Physics of Aftershocks in the South Iceland Seismic Zone : Insights into the earthquake process from statistics and numerical modelling of aftershock sequences

Lindman, Mattias January 2009 (has links)
In seismology, an important goal is to attain a better understanding of the earthquake process. In this study of the physics of aftershock generation, I couple statistical analysis with modelling of physical processes in the postseismic period. I present a theoretical formulation for the distribution of interevent times for aftershock sequences obeying the empirically well established Omori law. As opposed to claims by other authors, this work demonstrates that the duration of the time interval between two successive earthquakes cannot be used to identify whether or not they belong to the same aftershock sequence or occur as a result of the same underlying process. This implies that a proper understanding of earthquake interevent time distributions is necessary before conclusions regarding the physics of the earthquake process are drawn. In a discussion of self-organised criticality (SOC) in relation to empirical laws in seismology, I find that Omori's law for aftershocks cannot be used as evidence for the theory of SOC. Instead, I consider that the occurrence of aftershocks in accordance with Omori's law is a result of a physical process that can be modelled and understood. I analyse characteristic features in the spatiotemporal distribution of aftershocks in the south Iceland seismic zone, following the two M6.5 June 2000 earthquakes and a M4.5 earthquake in September, 1999. These features include an initially constant aftershock rate, whose duration is larger following a larger main shock, and a subsequent power law decay that is interrupted by distinct and temporary deviations in terms of rate increases and decreases. Based on pore pressure diffusion modelling, I interpret these features in terms of main shock initiated diffusion processes. I conclude that thorough data analysis and physics-based modelling are essential components in attempts to improve our understanding of processes governing the occurrence of earthquakes.
1005

Rocking shear wall foundations in regions of moderate seismicity

Van der Merwe, Johann Eduard 12 1900 (has links)
Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: In regions of moderate seismicity it has been shown that a suitable structural system is created when designing the shear wall with a plastic hinge zone at the lower part of the wall, with the shear walls resisting lateral loads and all other structural elements designed to resist gravity loads. A suitably stiff foundation is required for the assumption of plastic hinge zones to hold true. This foundation should have limited rotation and should remain elastic when lateral loads are applied to the structure. Ensuring a foundation with a greater capacity than the shear wall results in excessively large shear wall foundations being required in areas of moderate seismicity for buildings with no basement level. This study aims to investigate the feasibility of reducing the size of shear wall foundations in areas of moderate seismicity for buildings with no basement level. The investigation is aimed at allowing shear wall foundation rocking and taking into account the contribution of structural frames to the lateral stiffness of the structure. An example building was chosen to investigate this possibility. Firstly, lateral force-displacement capacities were determined for a shear wall and an internal reinforced concrete frame of this investigated building. Nonlinear momentrotation behaviour was determined for the wall foundation size that would traditionally be required as well as for six other smaller foundations. The above capacity curves against lateral loads were then used to compile a simplified model of the structural systems assumed to contribute to the lateral stiffness of the building. This simplified model therefore combined the effect of the shear wall, internal frame and wall foundation. Nonlinear time-history analyses were performed on this simplified model to investigate the dynamic response of the structure with different wall foundation sizes. By assessing response results on a global and local scale, it was observed that significantly smaller shear wall foundations are possible when allowing foundation rocking and taking into account the contribution of other structural elements to the lateral stiffness of the building. / AFRIKAANSE OPSOMMING: Daar is reeds getoon dat ʼn voldoende strukturele sisteem verkry word in gebiede van gematigde seismiese risiko indien ʼn skuifmuur ontwerp word met ʼn plastiese skarnier sone naby die ondersteuning van die muur. Skuifmure word dan ontwerp om weerstand te bied teen laterale kragte met alle ander strukturele elemente ontwerp om gravitasie kragte te weerstaan. Vir die aanname van plastiese skarnier sones om geldig te wees word ʼn fondasie met voldoende styfheid benodig. Só ʼn fondasie moet beperkte rotasie toelaat en moet elasties bly wanneer laterale kragte aan die struktuur aangewend word. ʼn Fondasie met ʼn groter kapasiteit as dié van die skuifmuur lei daartoe dat uitermate groot fondasies benodig word in gebiede van gematigde seismiese risiko vir geboue met geen kelder vlak. Hierdie studie is daarop gemik om die moontlikheid van kleiner skuifmuur fondasies te ondersoek vir geboue met geen kelder vlak in gebiede van gematigde seismiese risiko. Die ondersoek het ten doel om skuifmuur fondasie wieg aksie toe te laat en die bydrae van strukturele rame tot die laterale styfheid van die struktuur in ag te neem. Eerstens is die laterale krag-verplasing kapasiteit van ʼn skuifmuur en ʼn interne gewapende beton raam van die gekose gebou bepaal. Nie-lineêre moment-rotasie gedrag is bepaal vir die skuifmuur fondasie grootte wat tradisioneel benodig sou word asook vir ses ander kleiner fondasie grotes. Die bogenoemde kapasiteit kurwes is gebruik om ʼn vereenvoudigde model van die strukturele sisteme wat aanvaar word om laterale styfheid tot die gebou te verleen, op te stel. Hierdie vereenvoudigde model kombineer gevolglik die effek van die skuifmuur, interne raam en skuifmuur fondasie. Nie-lineêre tydgeskiedenis analises is uitgevoer op die vereenvoudigde model ten einde die dinamiese reaksie van die struktuur te ondersoek vir verskillende fondasie grotes. Resultate is beoordeel op ʼn globale en lokale vlak. Daar is waargeneem dat aansienlik kleiner skuifmuur fondasies moontlik is deur wieg aksie van die fondasie toe te laat en die bydrae van ander strukturele elemente tot die laterale styfheid van die gebou in ag te neem.
1006

Measuring liquefaction-induced deformation from optical satellite imagery

Martin, Jonathan Grant 11 September 2014 (has links)
Liquefaction-induced deformations associated with lateral spreading represent a significant hazard that can cause substantial damage during earthquakes. The ability to accurately predict lateral-spreading displacement is hampered by a lack of field data from previous earthquakes. Remote sensing via optical image correlation can fill this gap and provide data regarding liquefaction-induced lateral spreading displacements. In this thesis, deformations from three earthquakes (2010 Darfield, February 2011 Christchurch, and 2011 Tohoku Earthquakes) are measured using optical image correlation applied to 0.5-m resolution satellite imagery. The resulting deformations from optical image correlation are compared to the geologic conditions, as well as field observations and measurements of liquefaction. Measurements from optical image correlation are found to have a precision within 0.40 m in all three cases, and results agree well with field measurements. / text
1007

探討九二一地震後資源流失與因應行為對居民災後身心症狀的影響 / The effects of resources loss and coping behavior on psychological / physical symptoms after the 921 earthquake

謝孟晃 Unknown Date (has links)
本研究主要採用資源保存理論的壓力模式來檢驗921地震發生兩年半後,災區居民的資源流失與因應行為對身心症狀的影響,並比較不同社區組織與族群在資源流失、因應行為及身心症狀上的差異本研究主要採用問卷調查法,研究對象為南投埔里鎮居民,有效樣本共354份。受測樣本的設計分為目前住在組合屋和目前住在自己家中以及原住民和非原住民。研究工具包括「創傷後壓力反應指標問卷」、「資源流失調查表」及「因應量表」。資料的處理以相關分析、路徑分析、階層回歸分析和單因子共變數分析為主。本研究結果發現如下:(1)資源流失與逃避式的因應均能預測災區居民的身心症狀,但資源流失對身心症狀的預測要大於逃避式因應,且在四種類型的資源中,以個人資源流失的預測力最強。(2)在不同社區組織的比較中,組合屋居民出現較多身心症狀和資源的流失,且個人資源的流失和逃避式因應均是預測其身心症狀的最強變項。(2)在不同族群的比較中,原住民族群與非原住民族群在身心症狀和資源流失上沒有明顯差異,但原住民族群報告較多逃避式的因應,且逃避式的因應是預測其身心症狀的最強變項。根據研究結果,本研究對地震後的復建提出以下幾點建議:(1)減緩災難後資源的流失並增加資源的獲得。(2)社區組織的介入。(3)增強原住民族群的因應行為。 關鍵字:921地震、資源流失、因應行為、組合屋、原住民 / This study used the Conservation of Resources stress model to examine the effects of resources loss and coping behavior on psychological/physical symptoms after the 921 earthquake. And compared with the differences of resources loss, coping behavior and psychological/physical symptoms in different community organizations and races. This study was conducted by questionnaire investigation. 354 participants living in Pu-Li Town completed the questionnaires. The design of samples was distinguished between living in Temporal houses and living in own houses, and aborigines and non-aborigines. The measurements applied in this study included "Posttraumatic Stress Reaction Index Questionnaire", "Resources Loss Inventory" and "Coping Scale". The obtained data was analyzed by Pearson product-moment correlation, path analysis, hierarchical multiple regression analysis and one-way ANCOVA. The results of this study included: (1) resources loss and avoidant coping could predict psychological/physical symptoms, but resource loss predicted psychological symptoms better than avoidant coping. Personal resources were the strongest predictor among four kinds of resources. (2) In different community organizations. Temporal house's residents reported more resources loss and psychological/physical symptoms. And personal resources and avoidant coping were the strongest predictors. (3) In different races, the level of resources loss and psychological/physical symptoms were no significant differences between aborigines and non-aborigines. But aborigines revealed more avoidant coping and avoidant coping was the strongest predictor. Based on the results, some suggestions to post-earthquake rehabilitation were included: (1) Acting to limit resources loss after disaster and increase resources gain. (2) Considering the intervention of community organization. (3) Enhancing aborigine's coping behavior. Keywords: 921 earthquake, resource loss, coping behavior. Temporal houses, aborigines
1008

La situation des citoyens haïtiens parrainés au Québec après le séisme du 12 janvier 2010 en Haïti : une étude exploratoire des expériences migratoires

Saint Louis, Jessie Marie Michèle 06 1900 (has links)
Plusieurs milliers de citoyens haïtiens se sont établis au Québec après la survenue du séisme ayant frappé Haïti le 12 janvier 2010. Beaucoup d’entre eux ont été parrainés au Québec par leur famille. L’immigration au Canada en provenance d’Haïti a débuté à la fin des années 1950 en se concentrant plus particulièrement à Montréal. Le contexte politique, social et économique en Haïti est souvent cité dans la littérature pour expliquer le départ des Haïtiens et leur installation au Québec où la « communauté haïtienne » est estimée à environ 120 000 personnes. Nous avons mené une recherche qualitative exploratoire afin de mieux comprendre la situation de nouveaux arrivants haïtiens établis à Montréal suite au séisme. Pour cela, nous nous sommes inspirés des notions d'expérience (Dubet, 1994) et de représentation (Hall, 1997). Entre novembre 2012 et janvier 2013, nous avons réalisé neuf entrevues dont sept avec des femmes et deux avec des hommes âgés de 23 à 60 ans. Les résultats suggèrent que les participants accordent beaucoup d'importance à la vie dans le pays d'origine avant la migration dans l'élaboration de leurs expériences. L'expérience actuelle « ici » est élaborée en comparaison à l'expérience passée « là-bas ». Les participants insistent également sur l'importance du réseau familial lors du processus migratoire, à la fois dans les démarches d'émigration et dans l'accompagnement au pays d'accueil. Des émotions douloureuses ont été exprimées face à la séparation familiale, vécue comme une des conséquences de la migration. Les participants ont tous entamé des démarches d'insertion en emploi mais ils ont fait face à des difficultés dont la plupart d'entre eux qualifient de « structurelles » et que certains qualifient de difficultés « personnelles ». Enfin, les résultats indiquent que les participants sont porteurs d'un imaginaire migratoire qui s'exprime par des aspirations et des attentes par rapport à la société d'accueil et qui rend compte d’une tension entre ces aspirations et les expériences vécues. / Thousands of Haitian citizens have settled in Quebec after the occurrence of the earthquake that struck Haiti on January 12, 2010. Many of them have been sponsored in Quebec by their families. Immigration to Canada from Haiti began during the late 1950s focusing more particularly in Montreal. The political, social and economic context in Haiti is often cited in the literature to explain the departure of Haitians and their installation in Quebec where the 'Haitian community' is estimated at about 120,000 people. We conducted an exploratory qualitative research to better understand the situation of Haitian newcomers established in Montreal following the earthquake. To do this, we inspired by notions of experience (Dubet, 1994) and representation (Hall, 1997). Between November 2012 and January 2013, we carried out nine interviews with seven women and two men aged from 23 to 60 years. The results suggest that participants place great importance to life in the country of origin prior to migration in the development of their experiences. Experience current "here" is developed in comparison to experience past 'out there '. Participants also emphasized the importance of the family network when the migration process, both in the processes of emigration and in the accompaniment to the host country. Painful emotions were expressed against the separation family, lived as one of the consequences of the migration. Participants began efforts to integrate employment but they were faced with difficulties that most of them describe as "structural" and that some "personal". Finally, the results indicate that participants are carriers of an imaginary migration which is expressed by aspirations and expectations compared to the host society and which reflects a tension between these aspirations and experiences.
1009

Nurturing Natural Gas : Conflict and Controversy of Natural Gas Extraction in the Netherlands

Goossens, Tim January 2017 (has links)
No description available.
1010

Seeking Information After the 2010 Haiti Earthquake: a Case Study in Mass-fatality Management

Gupta, Kailash 05 1900 (has links)
The 2010 earthquake in Haiti, which killed an estimated 316,000 people, offered many lessons in mass-fatality management (MFM). The dissertation defined MFM in seeking information and in recovery, preservation, identification, and disposition of human remains. Specifically, it examined how mass fatalities were managed in Haiti, how affected individuals sought information about fatalities, and what needs motivated them. Data from 28 in-depth, partially structured interviews, conducted during two field visits ending 21 weeks after the earthquake, were included in a case study. The data analysis revealed the MFM was severely inadequate. One interviewee, a senior UN official, stated, "There was no fatality management." The analysis also indicated a need to learn whereabouts of the deceased motivated individuals to visit spots the deceased were last seen at. It sought to illumine information-seeking practices, as discussed in the works of J. David Johnson and others, by developing a new model of information flow in MFM. In addition, it reaffirmed Donald Case and Thomas Wilson's theoretical proposition – that need guides any seeking of information – in the case of Haiti. Finally, it produced recommendations regarding future directions in MFM for emergency managers and information scientists, including possible use of unidentified body parts in organ transplants. Overall, the dissertation, which was supported by two grants of the National Science Foundation, attempted to add to relatively scanty literature in information seeking in MFM.

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