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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.
731

Low-cost Seismic Base Isolation Using Scrap Tire Pads (stp)

Ozden, Bayezid 01 May 2006 (has links) (PDF)
This thesis focuses on the experimental studies conducted on the development of low-cost seismic base isolation pads using scrap automobile tires. Seismic base isolation is a well-defined building protection system against earthquakes, on which numerous studies have been conducted. The majority of the previous studies focus on the performance improvement of the base isolation systems. However, this study aims at cost and weight reduction of seismic base isolation pads by recycling otherwise useless material: scrap tires. Elastomer-based isolators have been heavily studied and used for the last 25 years. Steel or fiber reinforcement inside the elastomer isolators provides high vertical stiffness, whereas rubber segments between reinforcement layers provide low horizontal stiffness for the seismic base isolation. Since 1960&rsquo / s, automobile tires have been produced by means of vulcanizing rubber with steel mesh in different forms which have a similar effect as the steel plates or fibers inside the conventional elastomer-based isolators. Therefore, rectangular shaped layers cut from tread sections of used tires and then piled on top of each other can function as an elastomeric bearing. Since the tires are being designed for friction, load transfer between scrap tire layers would be large enough to keep all layers intact. A minimal slip generated between the piled layers at high strain rates may even help to dissipate some extra energy. Axial compression, dynamic free vibration, static shear and shaking table tests have been conducted on Scrap Tire Pads (STP) prepared by using different tire brands for different number of layers and orientations. The results have shown that the average shear modulus of STPs change between 0.9MPa and 1.85MPa. At the end of the dynamic tests it has been noticed that the lateral stiffness of STPs can be simply adjusted by changing the number of tread layers placed on top of each other. The amount of wire mesh inside the tire tread layers is relatively low compared to the steel plates in regular elastomeric pads / consequently, axial load capacity of STPs has been found to be around 8.0MPa. Static large deformation shear experiments have been performed to obtain the horizontal stiffness and shear modulus values at high strains and the results are tabulated in the manuscript. Steel and rubber layers are produced separately and just put on top of each other without any adhesive to form the &frac14 / scaled versions of STPs which were used to isolate a &frac14 / scaled masonry house on the shaking table available in METU Structural Laboratory. The experiment showed that non-vulcanized rubber-steel layers put on top of each other can also be used to isolate structures. In conclusion, STPs may be used as a low-cost alternative to conventional elastomer-based pads for seismic isolation of massive structures (e.g. stone wall rural masonry) or for temperature induced deformation compensation of rural bridges. STP usage is demonstrated using three hypothetical design examples in the manuscript.
732

台灣政府財產之地震與洪災風險管理- 以橋梁與建物為例 / Managing earthquake and flood risk of public properties in Taiwan-the case of bridges and buildings

林芝伶 Unknown Date (has links)
全球氣候變遷天災頻傳,全球溫室效應亦導致氣候異常,颱風、洪水等天然災害發生的頻率與損失幅度亦逐漸增加,在地球環境越趨變化快速與惡化之下,政府如何因應天災所帶來之損失與影響亦越趨重要。 本研究宗旨希冀能提高政府對於地震等巨災風險管理的重視,研究風險管理如何緩和地震及風災洪水對台灣政府財政之損害。本文將以台灣地區之地震造成政府財產中橋樑損失資料以及風災洪水造成公部門建物內容物毀損資料,模擬出可能損失金額。分析政府在利用三種不同保險機制後政府之損失與風險分散程度,並以現行於台灣之住宅地震保險基金分層承擔風險機制為例,將所模擬出之政府財產總損失套入基金,擴大住宅地震保險基金的承保範圍並設立洪水基金,分析政府存在基金下之財政支出與損失波動度。另計算政府財產在三種保險機制設計下,不同風險偏好之政府所需繳納之保費;最後一部分將檢視發行地震巨災債券的價值變化。 / Because of global climate change, natural disasters frequently happened all over the world. Global warming leads to climate anomalies, the frequency and loss severity of typhoons, floods and other natural disasters have also increased steadily. And under the Earth's environment changes and deteriorates rapidly, how should the government response to natural disasters are becoming more and more important. The purpose of this study is to attach importance to earthquake or other catastrophe risk management, and how to mitigate earthquake and flood catastrophes damage to the Taiwan government. The purpose of this study is to estimate the exposures of some public properties of Taiwan to earthquake and flood catastrophes. The research team was able to secure from National Center University two event loss tables on the earthquake risk of road bridges and the flood risk of government buildings. Based on these tables we simulated 500,000 earthquake and flood losses respectively and constructed two loss distributions. Then we imposed three insurance schemes to illustrate how risk management can mitigate the Nat Cat risks. We further enlarged the scope to all government properties based on the losses from the 921 earthquake and the Morakot typhoon. On these enlarged loss distributions we imposed risk management schemes similar to that of the Residential Earthquake Insurance Fund (TREIF) to investigate the potential benefits of risk management on the Nat Cat exposures of government properties. And we find optimal premiums under different insurance mechanism with different risk preferences of the government. The last part will examine the changes in the value of the issue of earthquake catastrophe bonds.
733

Application of the perfectly matched layers for seismic soil-structure interaction analysis in the time domain

Lee, Seung Ha January 2006 (has links)
Thesis (M.S.)--University of Hawaii at Manoa, 2006. / Includes bibliographical references (leaves 36-38). / x, 38 leaves, bound ill., map 29 cm
734

Seismic response of building façade system with energy absorbing connections

Hareer, Rahila Wardak January 2007 (has links)
Facades are popular in modern buildings and are made of different materials such as pre-cast concrete, glass, aluminium, granite or marble and steel. During recent times seismic activity in densely populated areas has resulted in damage and a consequent loss of life. There were many types of building failure, including failure of building facade systems. Facade systems are highly vulnerable and fail more frequently than the buildings themselves with significant devastating effects. During an earthquake building frames suffer large interstorey drifts, causing racking of the building facade systems. The facade systems may not be able to cater for such large deformations and this can result in either functional or total failure at the facade connections or damage by pounding (impact) with adjacent facade panels. Façade failure and collapse can cause serious damage to buildings and injury to people in the vicinity. Moreover, facade represent between 10- 20 % or more of the total building cost depending on the size and importance of the facility and facade material (Facades1980). Considering the cost and safety issues, the importance of a well designed facade system on a building needs to be emphasised. In modern buildings, energy absorbing passive damping devices are very commonly used for energy absorption in order to manage the vibration response of multistorey buildings in an earthquake event. A number of manufactured dampers such as Viscoelastic and viscous, friction and yielding dampers are available. These dampers use a range of materials and designs in order to achieve diverse levels of damping and stiffness. This thesis is an investigation of the seismic behaviour of building facade systems and studies the effects of facade and connection properties on this response. The objectives with energy absorbing connections of the study are to determine and control facade distortions and to establish the required connection properties. Finite Element techniques have been used for modelling and analysis of the building frame, facade and connections. Time history analyses under earthquake loadings were carried out to determine the system response in terms of inter-storey drifts, facade distortions, differential displacement between facades and frames and the axial force in horizontal connections. Connection properties with respect to stiffness and energy absorption capability (or damping) have been modelled and varied to obtain the desired response. Findings illustrate the influence of these connection properties on system response and show that it is possible to control facade distortions to within acceptable limits. They also demonstrate that energy absorbing connections are able to reduce inter-storey drifts and mitigate the detrimental seismic effects on the entire building facade system.
735

Geological control of physiography in Southeast Queensland : a mult-scale analysis using GIS

Hodgkinson, Jane Helen January 2009 (has links)
The study reported here, constitutes a full review of the major geological events that have influenced the morphological development of the southeast Queensland region. Most importantly, it provides evidence that the region’s physiography continues to be geologically ‘active’ and although earthquakes are presently few and of low magnitude, many past events and tectonic regimes continue to be strongly influential over drainage, morphology and topography. Southeast Queensland is typified by highland terrain of metasedimentary and igneous rocks that are parallel and close to younger, lowland coastal terrain. The region is currently situated in a passive margin tectonic setting that is now under compressive stress, although in the past, the region was subject to alternating extensional and compressive regimes. As part of the investigation, the effects of many past geological events upon landscape morphology have been assessed at multiple scales using features such as the location and orientation of drainage channels, topography, faults, fractures, scarps, cleavage, volcanic centres and deposits, and recent earthquake activity. A number of hypotheses for local geological evolution are proposed and discussed. This study has also utilised a geographic information system (GIS) approach that successfully amalgamates the various types and scales of datasets used. A new method of stream ordination has been developed and is used to compare the orientation of channels of similar orders with rock fabric, in a topologically controlled approach that other ordering systems are unable to achieve. Stream pattern analysis has been performed and the results provide evidence that many drainage systems in southeast Queensland are controlled by known geological structures and by past geological events. The results conclude that drainage at a fine scale is controlled by cleavage, joints and faults, and at a broader scale, large river valleys, such as those of the Brisbane River and North Pine River, closely follow the location of faults. These rivers appear to have become entrenched by differential weathering along these planes of weakness. Significantly, stream pattern analysis has also identified some ‘anomalous’ drainage that suggests the orientations of these watercourses are geologically controlled, but by unknown causes. To the north of Brisbane, a ‘coastal drainage divide’ has been recognized and is described here. The divide crosses several lithological units of different age, continues parallel to the coast and prevents drainage from the highlands flowing directly to the coast for its entire length. Diversion of low order streams away from the divide may be evidence that a more recent process may be the driving force. Although there is no conclusive evidence for this at present, it is postulated that the divide may have been generated by uplift or doming associated with mid-Cenozoic volcanism or a blind thrust at depth. Also north of Brisbane, on the D’Aguilar Range, an elevated valley (the ‘Kilcoy Gap’) has been identified that may have once drained towards the coast and now displays reversed drainage that may have resulted from uplift along the coastal drainage divide and of the D’Aguilar blocks. An assessment of the distribution and intensity of recent earthquakes in the region indicates that activity may be associated with ancient faults. However, recent movement on these faults during these events would have been unlikely, given that earthquakes in the region are characteristically of low magnitude. There is, however, evidence that compressive stress is building and being released periodically and ancient faults may be a likely place for this stress to be released. The relationship between ancient fault systems and the Tweed Shield Volcano has also been discussed and it is suggested here that the volcanic activity was associated with renewed faulting on the Great Moreton Fault System during the Cenozoic. The geomorphology and drainage patterns of southeast Queensland have been compared with expected morphological characteristics found at passive and other tectonic settings, both in Australia and globally. Of note are the comparisons with the East Brazilian Highlands, the Gulf of Mexico and the Blue Ridge Escarpment, for example. In conclusion, the results of the study clearly show that, although the region is described as a passive margin, its complex, past geological history and present compressive stress regime provide a more intricate and varied landscape than would be expected along typical passive continental margins. The literature review provides background to the subject and discusses previous work and methods, whilst the findings are presented in three peer-reviewed, published papers. The methods, hypotheses, suggestions and evidence are discussed at length in the final chapter.
736

Seismic design of unreinforced masonry structures / by Gregory Mark Klopp.

Klopp, Gregory Mark January 1996 (has links)
Addendum is pasted to back end-paper. / Bibliography: leaves 203-215. / xiii, 215 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis reports on the behaviour and design of unreinforced masonry buildings when subjected to forces induced into the structure from earthquake ground motion. The study involves the monitoring of ambient vibrations in a number of unreinforced masonry buildings in Adelaide to identify their dynamic properties. / Thesis (Ph.D.)--University of Adelaide, Dept. of Civil and Environmental Engineering, 1996
737

Seismic performance of reinforced concrete frames.

Kashyap, Jaya January 2009 (has links)
Many intra-tectonic plate regions are considered to have low to moderate seismic risk. However, devastating earthquakes can occur in these regions and result in high consequences in terms of casualties and damage. Non-ductile detailing practice employed in these structures make them prone to potential damage and failure during an earthquake. Furthermore, the use of infill walls is a divisive issue as on positive side dual wall-frame systems have beneficial effects related to strength, stiffness, and ductility. However, if not designed properly infill wall can also lead to undesirable structural failures of complete wall frame system. Although, there has been significant amount of international research in this area, it is worth noting that very little research exists for Australian frames. This thesis presents the experimental and analytical research conducted at The University of Adelaide to gain some insight into the behaviour of typically detailed Australian reinforced concrete frames subjected to ground motions. The main objectives of this research were (1) to investigate the behaviour of non-seismically designed reinforced concrete frames under a 500-YRP earthquake; (2) to determine the different magnitudes of earthquake (YRP) that are likely to cause excessive drifts in or collapse of gravity-load-designed reinforced concrete frames and (3) to investigate the effect of infill walls on the moment-resisting frames subjected to seismic loads. The experimental program consisted of earthquake simulation tests on a 1/5 scale model of a 3-storey reinforced concrete frame and four ½-scale reinforced concrete brick infilled frame specimens subjected to quasi-static cyclic loading. The analytical study included static pushover and non-linear dynamic analyses of the 3-, 5- and 12-storey reinforced concrete frames. From the overall performance of gravity-load-designed bare reinforced concrete frames considered in this study, it was concluded that the non-seismically designed frames appear to be capable of resisting a “design magnitude earthquake” (i.e., 500- YRP) in low earthquake hazard regions. However, their behaviour under more severe earthquakes (e.g. a 2500-YRP earthquake) is questionable. Perhaps the earthquake design requirements should consider as an alternative the ‘collapse prevention’ limit state for longer return period earthquakes, of the order of 2000–2500-YRP. The experimental research on reinforced concrete infilled frame indicated that the infill wall does not adversely effect the in plane ultimate strength, stiffness, and ductility of the bare reinforced concrete frame. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1372229 / Thesis (M.Eng.Sc.) - University of Adelaide, School of Civil, Environmental and Mining Engineering, 2009
738

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.
739

Formulating Disaster Recovery Plans for New Zealand: using a case study of the 1931 Napier Earthquake

Hollis, Melanie January 2007 (has links)
Worldwide, the risks from natural and technological hazards has been mounting at an accelerating rate, improvements in forecasting and warning systems have reduced deaths, however monetary losses from disasters are overwhelming (Burby, 2004). Pre event planning for recovery helps to resolve issues before a disaster so recovery is more efficient and effective. It also ensures that the window of opportunity can be used to implement hazard mitigation measures to reduce the vulnerability of the area with the aim of improving resilience for the next disaster. International case studies were examined, the Northridge earthquake being the most successful recovery while Hurricane Katrina the least. The recovery of the Napier 1931 earthquake was chosen as a New Zealand case study; to date this is the country's worst disaster. Overall the recovery of Napier was a success, shops were opened in temporary premises to keep the economy going and mitigation measures were included in the rebuilding. The earthquake has had important flow on effects on the way that disasters are managed in New Zealand. To create pre event plans in New Zealand legislation needs to be modified, including recovery plans and development of shortcuts to reduce some procedures which lengthen the recovery process. These plans need to take into account our national vulnerability as well as regional vulnerabilities.
740

Formulating disaster recovery plans for New Zealand : using a case study of the 1931 Napier earthquake : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Hazard and Disaster Management in the University of Canterbury /

Hollis, Melanie. January 1900 (has links)
Thesis (M. Sc.)--University of Canterbury, 2007. / Typescript (photocopy). Includes bibliographical references (leaves 123-127). Also available via the World Wide Web.

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