Dissertationen zum Thema „Earthquakes effects“
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1
Valle, Blandine C. „Effects of long duration earthquakes on bridge structures“. Online access for everyone, 2005. http://www.dissertations.wsu.edu/Thesis/Fall2005/b%5Fvalle%5F110805.pdf.
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2
Koyama, Junji. „Effects of earthquakes on partially-filled water tanks“. Thesis, Virginia Tech, 1994. http://hdl.handle.net/10919/43432.
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This thesis is concerned with the effects of earthquakes on partially-filled water tanks. The analysis is applicable to rectangular water tanks, which have received little attention to date. The analysis is relatively involved and includes the derivation of the equations of motion for the vibration of the whole of tank by means of substructure synthesis, a stochastic analysis relating the random ground motion caused by earthquakes to the random vibration of the tank, a stochastic characterization of the fluid pressure and computation of the probability of failure of the tank.
Master of Science
3
Koyama, Jun. „Effects of earthquakes on partially-filled water tanks /“. This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06232009-063240/.
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4
Parathiras, Achilleas N. „Displacement rate effects on the residual strength of soils“. Thesis, Imperial College London, 1994. http://hdl.handle.net/10044/1/7444.
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5
Rohanimanesh, Mohammad S. „Mutual pounding of structures during strong earthquakes“. Diss., This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06062008-144915/.
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6
Wilkinson, Sean. „Simplified analysis of asymmetric buildings subjected to earthquakes“. Thesis, Queensland University of Technology, 1997.
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7
Liperovskaya, E. V., Claudia-Veronika Meister, M. Parrot, V. V. Bogdanov und N. E. Vasil‘eva. „On Es-spread effects in the ionosphere connected to earthquakes“. Universität Potsdam, 2006. http://opus.kobv.de/ubp/volltexte/2007/1500/.
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In the present work, phenomena in the ionosphere are studied, which are connected with earthquakes (16 events) having a depth of less than 50 km and a magnitude M larger than 4. Analysed are night-time Es-spread effects using data of the vertical sounding station Petropavlovsk- Kanchatsky (φ=53.0°, λ=158.7°) from May 2004 until August 2004 registered every 15 minutes. It is found that the maximum distance of the earthquake from the sounding station, where pre-seismic phenomena are yet observable, depends on the magnitude of the earthquake. Further it is shown that 1-2 days before the earthquakes, in the premidnight hours, the appearance of Es-spread increases. The reliability of this increase amounts to 0.95.
8
Lee, F. H. „Centrifuge modelling of earthquake effects on sand embankments and islands“. Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372657.
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9
Al-Rawahy, Salim Y. S. „Effects of mining subsidence observed by time-lapse seismic reflection profiling“. Thesis, Durham University, 1995. http://etheses.dur.ac.uk/5125/.
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Extracting coal from underground mineworkings causes the overlying rocks to subside with associated changes in the stress regime. The aim of the study reported here was to apply the surface seismic reflection method to study the effect of subsidence on seismic velocity. Two sets of time-lapse surveys were carried out over two longwall mining panels in the Selby Coalfield. Seismic lines were profiled parallel and perpendicular to adjacent panels H45 and H46, respectively. A total of twenty-one repeated surveys were carried out along the two lines over a period of three years. The effect monitored was due to mining in the Bamsley Seam, at 550 m depth. As mining progressed, the traveltime of a strong reflection event from an anhydrite bed at 150 m depth was measured after processing the data with standard techniques. An overall increase in traveltime of about 4 % was observed. The progressive increase in traveltime over panel H45 correlated well with empirical calculations of differential subsidence between the surface and the anhydrite. However, the magnitude of the change must principally be accounted for by a decrease in seismic velocity, associated with a reduction in the vertical effective stress. Although the traveltime over panel H46 was also found to increase, and to correlate quite well with die expected differential subsidence, the agreement was less good along this transverse profile. This is attributed to asymmetric subsidence effects because the ground on the SW side of the panel had already been worked by panel H45, but the ground on the NE side was unworked. At the time of each seismic survey across panel H46, the profile was also levelled, and it was found that surface subsidence values along the profile increased towards panel H45. As most of the subsidence caused by mining panel H45 would have been completed by the time the H46 profile was surveyed, the effect must be at least partly attributed to asymmetric subsidence due to panel H46. Where the ground had been weakened by subsidence due to mining H45, near-total subsidence from mining H46 took place rapidly; but in the previously unworked ground on the NE side of panel H46, the residual subsidence was presumably delayed by competent strata in the overburden. Further work is needed to confirm whether this explanation is correct.
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Lopez, Ibaceta Alvaro Francisco. „Seismic Performance of Substandard Reinforced Concrete Bridge Columns under Subduction-Zone Ground Motions“. PDXScholar, 2019. https://pdxscholar.library.pdx.edu/open_access_etds/4977.
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A large magnitude, long duration subduction earthquake is impending in the Pacific Northwest, which lies near the Cascadia Subduction Zone (CSZ). Great subduction zone earthquakes are the largest earthquakes in the world and are the sole source zones that can produce earthquakes greater than M8.5. Additionally, the increased duration of a CSZ earthquake may result in more structural damage than expected. Given such seismic hazard, the assessment of reinforced concrete substructures has become crucial in order to prioritize the bridges that may need to be retrofitted and to maintain the highway network operable after a major seismic event. Recent long duration subduction earthquakes occurred in Maule, Chile (Mw 8.8, 2010) and Tohoku, Japan (Mw 9.0, 2011) are a reminder of the importance of studying the effect of subduction ground motions on structural performance. For this purpose, the seismic performance of substandard circular reinforced concrete bridge columns was experimentally evaluated using shake table tests by comparing the column response from crustal and subduction ground motions. Three continuous reinforced columns and three lap-spliced columns were tested using records from 1989 Loma Prieta, 2010 Maule and 2011 Tohoku. The results of the large-scale experiments and numerical studies demonstrated that the increased duration of subduction ground motions affects the displacement capacity and can influence the failure mode of bridge columns. Furthermore, more damage was recorded under the subduction ground motions as compared to similar maximum deformations under the crustal ground motion. The larger number of plastic strain cycles imposed by subduction ground motions influence occurrence of reinforcement bar buckling at lower displacement compared to crustal ground motions. Moreover, based on the experimental and numerical results, subduction zone ground motion effects are considered to have a significant effect on the performance of bridge columns. Therefore, it is recommended to consider the effects of subduction zone earthquakes in the performance assessment of substandard bridges, or when choosing ground motions for nonlinear time-history analysis, especially in regions prone to subduction zone mega earthquakes. Finally, for substandard bridges not yet retrofitted or upgraded seismically, the following performance limit recommendation is proposed: for the damage state of collapse, which is related to the ODOT's Life Safety performance level, the maximum strain in the longitudinal reinforcement should be reduced from 0.09 (in./in.) to a value of 0.032 (in./in.) for locations where subduction zone earthquakes are expected, to take into consideration the occurrence of bar buckling.
11
Fritsche, Stefan. „Large historical earthquakes in Switzerland : multidisciplinary studies on damage fields and site-effects /“. Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17710.
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12
Thompson, Theron James. „The effects of long-duration earthquakes on concrete bridges with poorly confined columns“. Online access for everyone, 2004. http://www.dissertations.wsu.edu/Thesis/Fall2004/T%5FThompson%5F090304.pdf.
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13
Waggoner, Sarah Elizabeth. „Effects of repetitive, small magnitude earthquakes on groundwater chemistry in Faulkner County, Arkansas“. OpenSIUC, 2011. https://opensiuc.lib.siu.edu/theses/586.
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The drive to find reliable sources of fuel that follow our green concerns and reduce our dependence on foreign sources of fossil fuels has pushed exploration and recovery of natural gas from within the United States to a top priority. Earthquakes generated from the use of hydraulic fracturing techniques and/or use of high pressure injection wells are occurring at an alarming rate due to increases in hydrocarbon exploration and recovery. While the link between earthquakes and hydrocarbon production is still uncertain, earthquake induced changes to groundwater chemistry are clear. Yet it has not been determined if repetitive, smaller earthquakes, i.e. earthquakes with magnitudes less than Mw<4.5, can result in similar disturbances to water chemistry as the more significant events have been proven to cause. Two known earthquake swarms, each having repetitive, small earthquake events, occurred in an intraplate setting in Faulkner County, Arkansas. Testing for groundwater chemical changes related to the timing of earthquake events and total energy released show that small earthquakes indeed create changes to groundwater chemistry most probably due to fluid intrusion from deep, chloride, calcium, and magnesium rich waters. The reduction of the United States dependence on foreign sources or finding green sources of fuel should not be the only mitigating factor for our decisions concerning our natural resources.
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Padgett, Jamie Ellen. „Seismic Vulnerability Assessment of Retrofitted Bridges Using Probabilistic Methods“. Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14469.
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The central focus of this dissertation is a seismic vulnerability assessment of retrofitted bridges. The objective of this work is to establish a methodology for the development of system level fragility curves for typical classes of retrofitted bridges using a probabilistic framework. These tools could provide valuable support for risk mitigation efforts in the region by quantifying the impact of retrofit on potential levels of damage over a range of earthquake intensities. The performance evaluation includes the development of high-fidelity three-dimensional nonlinear analytical models of bridges retrofit with a range of retrofit measures, and characterization of the response under seismic loading. Sensitivity analyses were performed to establish an understanding of the appropriate level of uncertainty treatment to model, assess, and propagate sources of uncertainty inherent to a seismic performance evaluation for portfolios of structures. Seismic fragility curves are developed to depict the impact of various retrofit devices on the seismic vulnerability of bridge systems. This work provides the first set of fragility curves for a range of bridge types and retrofit measures. Framework for their use in decision making for identification of viable retrofit measures, performance-based retrofit of bridges, and cost-benefit analyses are illustrated. The fragility curves developed as a part of this research will fill a major gap in existing seismic risk assessment software, and enable decision makers to quantify the benefits of various retrofits.
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Seid-Karbasi, Mahmood. „Effects of void redistribution on liquefaction-induced ground deformations in earthquakes : a numerical investigation“. Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/12868.
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Liquefaction-induced ground failure continues to be a major component of earthquake-related
damages in many parts of the world. Experience from past earthquakes indicates lateral spreads and flow slides have been widespread in saturated granular soils in coastal and river areas.
Movements may exceed several meters even in very gentle slopes. More interestingly, failures have occurred not only during, but also after earthquake shaking.
The mechanism involved in large lateral displacements is still poorly understood. Sand deposits often comprise of low permeability sub-layers e.g., silt seams. Such layers form a hydraulic barrier to upward flow of water associated with earthquake-induced pore pressures.
This impedance of flow path results in an increase of soil skeleton volume (or void ratio) beneath the barrier. The void redistribution mechanism as the focus of this study explains why residual strengths from failed case histories are generally much lower than that of laboratory data based
on undrained condition.
A numerical stress-flow coupled procedure based on an effective stress approach has been utilized to investigate void redistribution effects on the seismic behavior of gentle sandy slopes.
This study showed that an expansion zone develops at the base of barrier layers in stratified deposits subjected to cyclic loading that can greatly reduce shear strength and results in large deformations. This mechanism can lead to a steady state condition within a thin zone beneath the
barrier causing flow slide when a threshold expansion occurs in that zone. It was found that contraction and expansion, respectively at lower parts and upper parts of a liquefiable slope with a barrier layer is a characteristic feature of seismic behavior of such deposits. A key factor is the
pattern of deformations localized at the barrier base, and magnitude that takes place with some delay. In this thesis, a framework for understanding the mechanism of large deformations, and a practical approach for numerical modeling of flow slides are presented.
The study was extended to investigate factors affecting the seismic response of slopes, including: layer thickness, barrier depth and thickness, ground inclination, permeability contrast, base motion characteristics and soil consistency.
Another finding of this study was that a partial saturation condition results in delay in
excess pore pressure rise, and this factor may be responsible for the controversial behavior of the Wildlife Liquefaction Array, California (USA) during the 1987 Superstition earthquake.
It was demonstrated that seismic drains are a promising measure to mitigate the possible
devastating effects of barrier layers.
16
Haeri, Seyed Mohsen. „Response of earth and rockfill dams to strong earthquakes including dam-foundation interaction effects“. Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47094.
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17
Joshi, Varun Anil. „Near-Fault Forward-Directivity Aspects of Strong Ground Motions in the 2010-11 Canterbury Earthquakes“. Thesis, University of Canterbury. Department of Civil and Natural Resources Engineering, 2013. http://hdl.handle.net/10092/8987.
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The purpose of this thesis is to conduct a detailed examination of the forward-directivity characteristics of near-fault ground motions produced in the 2010-11 Canterbury earthquakes, including evaluating the efficacy of several existing empirical models which form the basis of frameworks for considering directivity in seismic hazard assessment.
A wavelet-based pulse classification algorithm developed by Baker (2007) is firstly used to identify and characterise ground motions which demonstrate evidence of forward-directivity effects from significant events in the Canterbury earthquake sequence. The algorithm fails to classify a large number of ground motions which clearly exhibit an early-arriving directivity pulse due to: (i) incorrect pulse extraction resulting from the presence of pulse-like features caused by other physical phenomena; and (ii) inadequacy of the pulse indicator score used to carry out binary pulse-like/non-pulse-like classification. An alternative ‘manual’ approach is proposed to ensure 'correct' pulse extraction and the classification process is also guided by examination of the horizontal velocity trajectory plots and source-to-site geometry. Based on the above analysis, 59 pulse-like ground motions are identified from the Canterbury earthquakes , which in the author's opinion, are caused by forward-directivity effects. The pulses are also characterised in terms of their period and amplitude. A revised version of the B07 algorithm developed by Shahi (2013) is also subsequently utilised but without observing any notable improvement in the pulse classification results.
A series of three chapters are dedicated to assess the predictive capabilities of empirical models to predict the: (i) probability of pulse occurrence; (ii) response spectrum amplification caused by the directivity pulse; (iii) period and amplitude (peak ground velocity, PGV) of the directivity pulse using observations from four significant events in the Canterbury earthquakes. Based on the results of logistic regression analysis, it is found that the pulse probability model of Shahi (2013) provides the most improved predictions in comparison to its predecessors. Pulse probability contour maps are developed to scrutinise observations of pulses/non-pulses with predicted probabilities.
A direct comparison of the observed and predicted directivity amplification of acceleration response spectra reveals the inadequacy of broadband directivity models, which form the basis of the near-fault factor in the New Zealand loadings standard, NZS1170.5:2004. In contrast, a recently developed narrowband model by Shahi & Baker (2011) provides significantly improved predictions by amplifying the response spectra within a small range of periods. The significant positive bias demonstrated by the residuals associated with all models at longer vibration periods (in the Mw7.1 Darfield and Mw6.2 Christchurch earthquakes) is likely due to the influence of basin-induced surface waves and non-linear soil response.
Empirical models for the pulse period notably under-predict observations from the Darfield and Christchurch earthquakes, inferred as being a result of both the effect of nonlinear site response and influence of the Canterbury basin. In contrast, observed pulse periods from the smaller magnitude June (Mw6.0) and December (Mw5.9) 2011 earthquakes are in good agreement with predictions. Models for the pulse amplitude generally provide accurate estimates of the observations at source-to-site distances between 1 km and 10 km. At longer distances, observed PGVs are significantly under-predicted due to their slower apparent attenuation. Mixed-effects regression is employed to develop revised models for both parameters using the latest NGA-West2 pulse-like ground motion database. A pulse period relationship which accounts for the effect of faulting mechanism using rake angle as a continuous predictor variable is developed. The use of a larger database in model development, however does not result in improved predictions of pulse period for the Darfield and Christchurch earthquakes. In contrast, the revised model for PGV provides a more appropriate attenuation of the pulse amplitude with distance, and does not exhibit the bias associated with previous models.
Finally, the effects of near-fault directivity are explicitly included in NZ-specific probabilistic seismic hazard analysis (PSHA) using the narrowband directivity model of Shahi & Baker (2011). Seismic hazard analyses are conducted with and without considering directivity for typical sites in Christchurch and Otira. The inadequacy of the near-fault factor in the NZS1170.5: 2004 is apparent based on a comparison with the directivity amplification obtained from PSHA.
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Fuchs, Florian [Verfasser]. „Dynamic triggering: The effects of remote earthquakes on volcanoes, hydrothermal systems and tectonics / Florian Fuchs“. Bonn : Universitäts- und Landesbibliothek Bonn, 2015. http://d-nb.info/1077289243/34.
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Hoel, Karin Harnæs, und Bjørn Thomas Svendsen. „The Effects of Near-fault Earthquakes On a High-rise Structure In The Oslo Area“. Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for konstruksjonsteknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18539.
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The objective of the presented research is to evaluate the seismic response of a high-rise structure located in a seismic environment. For this purpose, the Oslo Plaza building located in Oslo, Norway, was chosen. A numerical element model of the building was created in the structural analysis program SAP2000 with emphasis on the soil-structure interaction representation. A structural monitoring process with the intention of calibrating the model was performed. The focus was to estimate and evaluate the dynamic behavior and response of the high-rise structure to strong ground motion, with emphasis on near-fault ground motion. For this purpose, simulations and modifications of ground motion data was performed. The seismic response of the structure with emphasis on important damage parameters of special concern for tall structures such as displacement, interstory drift and base shear were investigated. It was found that near-fault earthquakes results in larger seismic response than far-fault earthquakes for the high-rise structure considered. The near-fault ground motion rendered larger interstory drift which was found to be decisive at critical floors, as expected. Analyses of the existing point bearing foundation resulted in less seismic response than an alternative foundation representation modeled in SAP2000. Oslo Plaza was found to perform well considering the response parameters taken into consideration for the different seismic scenarios. A seismic design according to Eurocode 8 and the National Annex of Norway is sufficient for high-rise structures like Oslo Plaza. An exception was found investigating the P-Δ effects. The study does not incorporate design checks of the structure.Keywords: Near-fault Ground Motion; High-rise Structure; Interstory Drift; Soil-structure Interaction; Oslo; Structural Monitoring.
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Vitoontus, Soravit. „Risk assessment of building inventories exposed to large scale natural hazards“. Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43676.
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Earthquakes are among the most devastating and unpredictable of natural hazards that affect civil infrastructure and have the potential for causing numerous casualties and significant economic losses over large areas. Every region that has the potential for great earthquakes should have an integrated plan for a seismic design and risk mitigation for civil infrastructure. This plan should include methods for estimating the vulnerability of building inventories and for forecasting economic losses resulting from future events. This study describes a methodology to assess risk to distributed civil infrastructure due to large-scale natural hazards with large geographical footprints, such as earthquakes, hurricanes and floods, and provides a detailed analysis and assessment of building losses due to earthquake. The distinguishing feature of this research, in contrast to previous loss estimation methods incorporated in systems such as HAZUS-MH, is that it considers the correlation in stochastic demand on building inventories due to the hazard, as well as correlation in building response and damage due to common materials, construction technologies, codes and code enforcement. These sources of correlation have been neglected, for the most part, in previous research. The present study has revealed that the neglect of these sources of correlation leads to an underestimation of the estimates of variance in loss and in the probable maximum loss (PML) used as a basis for underwriting risks. The methodology is illustrated with a seismic risk assessment of building inventories representing different occupancy classes in Shelby County, TN, considering both scenario earthquakes and earthquakes specified probabilistically. It is shown that losses to building inventories estimated under the common assumption that the individual losses can be treated as statistically independent may underestimate the PML by a factor of range from 1.7 to 3.0, depending on which structural and nonstructural elements are included in the assessment. A sensitivity analysis reveals the statistics and sources of correlation that are most significant for loss estimation, and points the way forward for supporting data acquisition and synthesis.
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Moore, Andrew. „The Effects of the Earthquakes on the Classical Musical Life of Christchurch, September 2010 - May 2013“. Thesis, University of Canterbury. Music, 2013. http://hdl.handle.net/10092/9458.
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As part of the Canterbury Earthquake Digital Archive, this thesis documents the effects of the earthquakes on the musical life of Christchurch. It concentrates, primarily, on the classical music scene. The thesis examines the difficulties experienced by musical organisations, individual musicians, and teachers as they sought to bring music to the broken city, together with the measures that were necessary in order to overcome those difficulties. It examines how those organisations have worked to re-establish themselves in their particular musical fields. It charts the progress made, to date, along the path to recovery and offers suggestions regarding precautionary measures which, if instituted, could reduce the after-effects of a future disaster. Recognising that not all of the difficulties encountered were directly related to the earthquakes, this thesis also examines the effects on music and musicians, of decision making associated with the recovery effort.
The thesis also demonstrates how a destructive event can provide the inspiration for creativity. It recognises the importance of music in maintaining a sense of normality for people, whether they realise it or not, as well as its influences in providing emotional relief in times of stress. Hopefully, it may become a useful guide to which other cities that may be faced with some natural disaster, could refer.
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Ryan, Megan Elizabeth. „The effects of the Christchurch earthquakes of 2010 and 2011 on the quality of life of children and adolescents with disabilities“. Thesis, University of Canterbury. School of Health Sciences, 2015. http://hdl.handle.net/10092/10741.
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This study explored the effects of the Canterbury earthquakes of 2010 and 2011 on different areas of quality of life (QOL) for children and adolescents with disabilities. Using a survey developed from the Quality of Life Instrument for People with Developmental Disabilities – Short Version (QOL-PDD-SV) (Brown, Raphael & Renwick, 1997) and The World Health Organisation Quality of Life - (WHOQOL)-BREF, parents or caregivers were asked to identify what level of importance and satisfaction their child or adolescent placed on areas of QOL including physical health, psychological health - stress levels and coping ability, attachment to their neighbourhood, friends, family, leisure activities, community access and schooling. They were also asked to determine what level of impact the earthquakes had had on each area of their child or adolescent’s life and overall quality of life in the aftermath of the earthquakes. A total of 31 parents of 22 males and 9 females between the ages of 2.5 years to 19 years of age (mean age: 12.6 years) responded. The results were collated and analysis was run to measure for the effect of age, gender and geographical location. The results found that the earthquakes affected nearly every area of QOL for the children and adolescents. The biggest impact on the children’s psychological health and their ability to cope It was observed that younger children (<13) were more likely to record improved or lessened effects from the earthquakes in psychological health areas. However, the areas of social belonging and friendships were the least affected by the earthquakes. Female children were more likely to indicate higher scores for social belonging after the earthquakes. Many parents observed that their children developed improved coping skills over the earthquake period. The findings in this study offer a better understanding of how earthquakes can affect the quality of life children and adolescents with disabilities.
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McDaniel, Caleb Alan. „The effects of grain size on the strength of magnesite aggregates deforming by low temperature plasticity and diffusion creep“. University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1526571269872349.
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Lillo, Bustos Nicolás A. „Essays on the effects of the Homestead Act on land inequality and human capital, the effects of land redistribution on crop choice, and the effects of earthquakes on birth outcomes“. Thesis, University of Warwick, 2017. http://wrap.warwick.ac.uk/113453/.
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Chapter 1: Land Inequality and Human Capital: Evidence for the United States from the Homestead Act. This chapter uses historical records of land patents and county level census data to estimate the impact of the Homestead Act of 1862 |an egalitarian land distribution policy implemented in the United States| on land inequality, school enrolment, and literacy during the late nineteenth and early twentieth centuries. The results show that the Homestead Act reduced land inequality and increased school enrolment and literacy, and that there is not heterogeneous effects on school enrolment by sex, but the effect is driven by the impact on children of primary school age. Using the Homestead Act as an instrument for land inequality, the results show that land inequality had a strong negative impact on school enrolment. This result is relevant to the literature because identification does not rely on variation across geographic, climatic, or soil characteristics. These results are robust to the inclusion of state specific year fixed effects and are not driven by convergence. On the contrary, I argue that convergence in school enrolment was a consequence of the Homestead Act. Chapter 2: Land Redistribution and Crop Choice: Evidence from Reform and Counter-Reform in Chile. This chapter uses unique historical data on the Chilean land reform of the 1960s and 1970s to estimate the impact that redistribution had on land inequality and crop choice. The results show that land redistribution had a persistent negative effect on land inequality, and that areas that were treated with more reform increased their share of land cultivated with fruits, vegetables, and vineyards, and lowered the share of land destined to forest plantations. The fact that a military coup interrupted the reform process allows for the comparison of the effects of reform and counter-reform, which sheds light on the mechanisms through which redistribution operated. I find that land that was transferred to new owners drive the results for crop choice, but not those for land inequality. Chapter 3: Earthquakes and Birth Outcomes in Chile. This chapter estimates the e effects of earthquakes on birth weight and length of gestation. I use administrative data on the universe of live births in Chile between 1994 and 2011. I combine that data with GIS raster information from USGS ShakeMaps to assign a detailed measure of earthquake intensity for each birth during each trimester of pregnancy. I find that, although the baseline estimates suggest a weak negative effect, these results are not robust to the exclusion of births from a strong 8.8 magnitude earthquake that struck off the coast of south-central Chile, which caused approximately 500 casualties, heavy infrastructure damage, and significant disruption to the government's logistics.
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Renouf, Charlotte Alicia. „Do the Psychological Effects of Ongoing Adversity in a Natural Context Accumulate or Lessen over Time? The Case of the Canterbury Earthquakes“. Thesis, University of Canterbury. Department of Psychology, 2012. http://hdl.handle.net/10092/7397.
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The current study examined the psychological effects of recurring earthquake aftershocks in the city of Christchurch, New Zealand, which began in September 2010. Although it has been identified that exposure to ongoing adverse events such as continuing terrorist attacks generally leads to the development of increasing symptomology over time, differences in perceived controllability and blame between man-made and natural adverse events may contribute to differences in symptom trajectories. Residents of two Christchurch suburbs differentially affected by the earthquakes (N = 128) were assessed on measures of acute stress disorder, generalised anxiety, and depression, at two time points approximately 4-5 months apart, in order to determine whether symptoms intensified or declined over time in the face of ongoing aftershocks. At time 1, clinically significant levels of acute stress were identified in both suburbs, whereas clinical elevations in depression and anxiety were only evident in the most affected suburb. By time 2, both suburbs had fallen below the clinical range on all three symptom types, identifying a pattern of habituation to the aftershocks. Acute stress symptoms at time 2 were the most highly associated with the aftershocks, compared to symptoms of generalised anxiety and depression which were identified by participant reports to be more likely associated with other earthquake-related factors, such as insurance troubles and less frequent socialisation. The finding that exposure to ongoing earthquake aftershocks leads to a decline in symptoms over time may have important implications for the assessment of traumatic stress-related disorders, and provision of services following natural, as compared to man-made, adverse events.
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Connolly, Maria Josephine. „The impacts of the Canterbury earthquakes on educational inequalities and achievement in Christchurch secondary schools“. Thesis, University of Canterbury. Geography, 2013. http://hdl.handle.net/10092/7903.
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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.
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Acar, Fikri. „Low Cycle Fatigue Effects In The Damage Caused By The Marmara Earthquake Of August 17, 1999“. Phd thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/2/12605534/index.pdf.
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This study mainly addresses the problem of estimating the prior earthquake damage on the response of reinforced concrete structures to future earthquakes. The motivation has arisen from the heavy damages or collapses that occurred in many reinforced concrete structures following two major earthquakes that recently occurred in the Marmara Region, Turkey.
The analysis tool employed for this purpose is the package named IDARC2D. Deterioration parameters of IDARC's hysteretic model have been calibrated using a search method. In the calibration process experimental data of a total of twenty-two beam and column specimens, tested under constant and variable amplitude displacement histories, has been used. Fine-tuning of deterioration parameters is essential for more realistic predictions about inelastic behavior and structural damage. In order to provide more realistic damage prediction, three ranges of parameters are proposed. Some damage controlling structural parameters have been assessed via a large number of two-dimensional section analyses, inelastic time history and damage analyses of SDOF systems and seismic vulnerability analyses of reinforced concrete buildings. Inelastic time history and damage analyses of numerous SDOF systems have been carried out to determine whether the loading history has an effect on damage and dissipated hysteretic energy. Then this emphasis is directed to the analyses of MDOF systems. In the analyses of the SDOF systems, various forms of constant and variable amplitude inelastic displacement reversals and synthetic ground motions composed of one of the four earthquake records preceded or followed by its modified records acted as a prior or successive earthquake, have been used. The analyses of two five-story R/C buildings have been caried out using synthetic accelerograms comprised of base input provided by the two recorded ground motions. It is shown that both damage progression and cumulative hysteretic energy dissipated along a path seem to depend on the number and amplitude of cycles constituting the path. However, final damage and accumulated hysteretic energy dissipated along a loading path are independent of the ordering of the same number and amplitude cycles along the path. There is a nonlinear relationship between the earthquake excitation intensity and final damage attained in the end. Increase in the acceleration amplitude leads to exponential increase in damage. As the prior earthquake intensity increases the damage from the succeding main earthquake decreases. A definite ground motion acting as prior and successive earthquake causes substantially different amount of damage. Prior earthquake damage does not substantially affect the maximum drift response in future larger earthquakes. A MDOF frame type structure with aprior damage suffers less overall damage in an earthquake in comparison with the one without a prior damage.
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Rault, Claire. „Effets de site, endommagement et érosion des pentes dans les zones épicentrales des chaînes de montagnes actives“. Thesis, Paris Sciences et Lettres (ComUE), 2019. http://www.theses.fr/2019PSLEE006/document.
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Les glissements de terrain constituent un risque naturel majeur à l’origine de dégâts matériels et humains considérables. Les séismes sont l’une des principales causes de leur déclenchement dans les orogènes actifs. Dans la zone épicentrale, le passage des ondes sismiques perturbe le champs de contraintes local ce qui peut provoquer le dépassement du seuil de stabilité des versants. La probabilité de déclenchement d’un glissement de terrain sismo-induit sur une pente donnée est donc fonction de facteurs liés au mouvement du sol et aux caractéristiques géologiques et topographiques de celle-ci. Très peu de données sismiques sont disponibles sur les versants et les modèles d’interpolation sont peu précis. Or le mouvement sismique peut s’avérer très variable à l’échelle d’un bassin du fait de la présence d’effets de site. L’étude de la réponse sismique d’un relief taïwanais nous permet de documenter ces effets et de prendre connaissance de la complexité du mouvement enregistré sur ce relief à la suite du passage de l’onde. Un réseau de six stations larges-bandes a été déployé, au travers de ce relief large d’environ 3km. Entre mars 2015 et juin 2016, ce réseau a permis d’enregistrer la réponse des sites à plus de 2200 séismes régionaux (magnitude Ml>3, distance hypocentrale<200km). Bien que distants de quelques centaines de mètres, les sites présentent tous une réponse qui leur est caractéristique résultant d’une combinaison complexe entre la topographie et la géologie du site. A fréquences modérées, correspondant à des longueurs d’ondes du mouvement pouvant contribuer au déclenchement de glissements de terrain, l’amplification du mouvement sismique est principalement due à la géologie locale et non à la topographie, comme montré par les indicateurs classiques (SSR, PGA, PGV et Arias) extraits des réponses des stations aux séismes. La topographie semble néanmoins jouer un rôle dans la durée du mouvement sismique fort aux stations situées sur les crêtes et en bordure de bassin sédimentaire, par effet de résonance et génération d’ondes de surface. La contribution prédominante de la géologie dans le déclenchement des glissements de terrain sismo-induits est également montrée par l’analyse de leur position sur les versants pour les glissements associés aux séismes de Northridge (Mw 6.7, 1994, Etats-Unis), de Chi-Chi (Mw 7.6, 1999, Taiwan), et de Wenchuan (Mw 7.9, 2008, Chine). En effet, bien que les glissements sismo-induits se localisent statistiquement plus haut sur les versants que les glissements d’origine climatique, on note que cette tendance est fortement modulée par la géologie des bassins. En fonction des « attracteurs », tels que des failles ou forts contrastes lithologiques, présents dans les bassins, les glissements tendent à se déclencher plus ou moins haut sur les versants, là où le potentiel de rupture est plus fort. Les propriétés mécaniques des pentes sont peu contraintes dans les zones montagneuses. Souvent leurs paramètres géotechniques sont estimés à partir des cartes géologiques régionales, or ils peuvent varier fortement pour une même lithologie d’un bassin à un autre. En considérant un modèle frictionnel simple de stabilité des pentes, on propose d’inverser des paramètres de type Coulomb à partir de la distribution des pentes des glissements de terrain sismo-induits à l’échelle des bassins dans les zones épicentrales des séismes de Northridge, Chi-Chi et Wenchuan. La variation spatiale de ces paramètres semble cohérente avec celle de la lithologie et la profondeur des solsLandslides are a major natural hazard that cause significant damages and casualties to people. Earthquakes are one of their main triggers in active mountain belts. In epicentral area, the passage of seismic-waves that disrupt the stress-field, leads the slope stability threshold to be exceeded. Co-seismic slope failure probability thus depends on complex interactions between the ground-motion and the slope geology and geometry. A few seismic data are available on mountain slopes and the resolution of ground-motion models is generally low. Yet strong variation of ground-motion from one ridge to another can be felt due to site effects. We document site effects across topography and show the complexity of slope responses to earthquakes using a seismic network set across a Taiwanese ridge. Six broadband seismometers were set along the profile of this 3km wide ridge. From March 2015 to June 2016, more than 2200 earthquakes (magnitude Ml>3 and hypocentral distance<200km) were recorded. Although the sites are within a distance of hundreds of meters they all show different characteristic responses that are related to a complex combination of the geology and topography of the sites. At medium frequency corresponding to groundmotion wavelength that could affect slope stability, the ground-motion amplification is mostly related to the local geology and the topographic effect seems relatively negligible as attested by current indicators measured at the stations (PGA, PGV, Arias, SSR). However the duration of strong ground-motion at the ridge crests and slope toe seems to be related to possible resonance effects and surface wave generation due to the geometry of the topography. The strong contribution of the geology to co-seismic landslide trigger is demonstrated by the analysis of their position along hillslopes for the co-seismic landslides triggered by the Northridge earthquake (Mw 6.7, 1994, USA), the Chi-Chi earthquake (Mw 7.6, 1999, Taiwan), and the Wenchuan earthquake (Mw 7.9, 2008, China). Indeed, although co-seismic landslides are statistically located higher on hillslopes than the rainfall-induced landslides, we show that this tendency is strongly modulated by the geology. According to the “potential landslides attractiveness” of geological structures, such as faults or lithological contrasts, present in the watershed, the slope failure would occur more or less upslope, where the failure probability is the highest.Slope mechanical properties are not well constrained in mountain area. Their geotechnical parameters are usually estimated using information provided by geological maps, but even for the same lithology they can strongly differ for one basin to another. Considering one simple friction model for seismic slope stability, we propose to invert Coulomb related parameters using the slope distributions of the landslides triggered by the Northridge, Chi-Chi and Wenchuan earthquakes. The spatial variation of these parameters seems to be in agreement with the lithology and soil depth at the first order
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Brax, Marleine. „Aléa et microzonage sismiques à Beyrouth“. Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENU050.
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Le Liban n'a pas souffert de grands tremblements de terre destructeurs depuis près de deux siècles. Il est toutefois traversé par la faille transformante majeure du Levant, séparant sur1000 km de longueur la plaque Arabique à l’est de la plaque Africaine à l’ouest. Ses principales branches au Liban sont la faille de Yammouneh qui traverse le pays du sud au nord, les failles de Serghaya et Rachaya dans sa partie Est, la faille de Roum et les failles inverses du Mont Liban dans la partie Ouest. Ces failles ont généré des séismes destructeurs dans la longue histoire connue de la région, parmi lesquels les plus importants sont ceux deJuillet 551 sur la faille du Mont-Liban, de mai 1202 sur la faille de Yammouneh, d’Octobre1759 sur la faille de Rachaya et de Novembre 1759 sur la faille de Serghaya. L'évaluation del'aléa et du risque sismique local est donc de première importance pour l'ensemble du pays.L'objectif du travail effectué dans cette thèse est d'appliquer au Liban les avancées réalisées ces dernières années dans le développement de nouveaux outils à la fois fiables et économiquement abordables pour l’évaluation de l’aléa sismique, en commençant par les grandes villes et en particulier la capitale Beyrouth. L'objectif est de mieux appréhender et comprendre le risque sismique sur le territoire libanais, pour pouvoir ensuite commencer à élaborer des politiques de prévention et des codes parasismiques qui puissent le réduire à terme.Un réseau sismologique temporaire composé de 10 stations a été installé dans Beyrouth etune partie de sa banlieue sur des sites représentatifs des principales unités géologiques présentes. Plusieurs dizaines de séismes locaux et régionaux ont pu y être enregistrés, et leur réponse sismique a été évaluée par la méthode du rapport spectral site sur référence (SSR),comparé au rapport spectral de la composante horizontale sur la composante verticale (H/V)calculé sur les tremblements de terre et sur le bruit ambiant. Les mêmes enregistrements ont également été utilisés pour prédire, par la technique des Fonctions de Green empiriques(FGE), le mouvement sismique correspondant à un événement majeur (Mw7.5) sur la faille de Yammouneh. Cet exercice de prédiction a toutefois été réalisé en deux étapes en raison des limitations dans l'application de la technique FGE en champ proche, avec deux techniques complémentaires: l'enregistrement d’un petit événement a été d'abord utilisé pour simuler un séisme de Mw6.5 sur la faille de Yammouneh, en parallèle à l'utilisation de plusieurs équations de prédiction de mouvement du sol (GMPE), soigneusement sélectionnées, pour effectuer une prédiction similaire. La comparaison FGE/GMPE a alors permis de calibrer la prédiction du mouvement du sol par GMPE à différents sites de Beyrouth pour l'événement cible de Mw7.5. Ces résultats ponctuels ont ensuite été étendus à l'ensemble de la municipalité de Beyrouth et de sa banlieue proche, en vue de mieux cerner les contours d'une future carte de microzonage, au travers d'une vaste campagne de mesures de bruit ambiant sur615 sites. Leur traitement H/V a permis d’obtenir une carte de la fréquence de résonance pour l'ensemble de la zone, carte dont la robustesse a été testée et prouvée. Des mesures sismiques actives et passives ont en outre été menées sur les principales unités géologiques à proximité des 10 sites préalablement sélectionnés et instrumentés, permettant ainsi d'obtenir les premières estimations directes de la vitesse des ondes de cisaillement (via les courbes de dispersion des ondes de Rayleigh). La comparaison de ces mesures avec les estimations -très dispersées - issues de la compilation des paramètres géologiques/géotechniques disponibles et des équations de corrélation existantes avec les valeurs N des SPT, montre tout l'intérêt de ces mesures simples et fiablesLebanon is one of the countries that have not suffered from large destructive earthquakes foralmost two centuries. It is however lying on the 1000 km long, left lateral Levant fault thatseparates the Arabic plate in the east from the African plate in the west. Its main branches inLebanon are the Yammouneh fault that crosses the country from south to north, the Serghayaand Rachaya faults in its Eastern part, the Roum and Mount Lebanon Thrust faults in itsWestern part. These faults have generated destructive earthquakes in the long known historyof the area. The largest events are: The July 551 earthquake on the Mount Lebanon Thrustfault, the May 1202 earthquake on the Yammouneh fault, the October 1759 on the Rachayafault and the November 1759 on the Serghaya fault. From all above, one can conclude thatLebanon is exposed to a significant seismic hazard. Assessing the local seismic hazard andrisk is therefore of primary importance for the whole country.The objective of the work undergone in this PhD is to take advantage of the latest advancesachieved worldwide to promote rather inexpensive, though reliable, seismic hazardassessment tools, to try to apply them in Lebanon starting with the big cities and specificallythe capital Beirut. These studies will help to understand the Lebanese seismic risk andsubsequently to start to elaborate seismic policies and codes that may help reducing this risk.A temporary seismological network consisting of 10 stations has been installed in Beirut anda part of its suburbs. Several tens of local and regional earthquakes could be recorded, andallowed to estimate the site response at selected sites in Beirut through the standard site toreference spectral ratio method ("SSR") on earthquakes, compared to the horizontal tovertical ratio ("H/V") calculated on earthquakes and on ambient noise. The same recordingscould also be used via the empirical Green Function’s technique ("EGF") to predict theseismic ground motion corresponding to a Mw7.5 on the Yammouneh fault. However, due tolimitations in near-field applications of the EGF technique, this prediction exercise wasperformed in two steps and with two complementary techniques: a weak event recording wasfirst used to simulate a Mw6.5 earthquake on the Yammouneh fault, while several, carefullyselected ground motion prediction equations (GMPE) were used to perform a comparativeprediction for the same earthquake. This EGF/GMPE comparison then allowed tuning theGMPE prediction of ground motion at various sites within Beirut for the target Mw7.5 event.The results were then extended in view of proposing a framework for a future microzonationviimap. A comprehensive campaign of ambient noise measurements was achieved for 615 sitesof Beirut municipality and close suburbs, the H/V processing of which allowed to derive arobust map of resonance frequency for the whole area. In addition, active and passive seismicmeasurements were conducted on different geological units near the 10 formerlyinstrumented sites, which provided quantitative estimates of the shallow S-wave velocitythrough the Rayleigh wave dispersion curves. These geophysical measurements permitted toprovide direct estimates of the shear waves velocity, which prove much more reliable thanthe highly scattered estimates derived from the compilation of the availablegeological/geotechnical parameters and the use of existing correlations equations betweenSPT N-value and S-wave velocity Vs
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Hill-Butler, C. „Evaluating the effect of large magnitude earthquakes on thermal volcanic activity : a comparative assessment of the parameters and mechanisms that trigger volcanic unrest and eruptions“. Thesis, Coventry University, 2015. http://curve.coventry.ac.uk/open/items/5f612a7d-ebbf-4d38-90aa-89c4984a1c0f/1.
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Volcanic eruptions and unrest have the potential to have large impacts on society causing social, economic and environmental losses. One of the primary goals of volcanological studies is to understand a volcano’s behaviour so that future instances of unrest or impending eruptions can be predicted. Despite this, our ability to predict the onset, location and size of future periods of unrest remains inadequate and one of the main problems in forecasting is associated with the inherent complexity of volcanoes. In practice, most reliable forecasts have employed a probabilistic approach where knowledge of volcanic activity triggers have been incorporated into scenarios to indicate the probability of unrest. The proposed relationship between large earthquakes and volcanic activity may, therefore, indicate an important precursory signal for volcanic activity forecasting. There have been numerous reports of a spatial and temporal link between volcanic activity and high magnitude seismic events and it has been suggested that significantly more periods of volcanic unrest occur in the months and years following an earthquake than expected by chance. Disparities between earthquake-volcano assessments and variability between responding volcanoes, however, has meant that the conditions that influence a volcano’s response to earthquakes have not been determined. Using data from the MODVOLC algorithm, a proxy for volcanic activity, this research examined a globally comparable database of satellite-derived volcanic radiant flux to identify significant changes in volcanic activity following an earthquake. Cases of potentially triggered volcanic activity were then analysed to identify the earthquake and volcano parameters that influence the relationship and evaluate the mechansisms proposed to trigger volcanic activity following an earthquake. At a global scale, this research identified that 57% [8 out of 14] of all large magnitude earthquakes were followed by increases in global volcanic activity. The most significant change in volcanic radiant flux, which demonstrates the potential of large earthquakes to influence volcanic activity at a global scale, occurred between December 2004 and April 2005. During this time, new thermal activity was detected at 10 volcanoes and the total daily volcanic radiant flux doubled within 52 days. Within a regional setting, this research also identified that instances of potentially triggered volcanic activity were statistically different to instances where no triggering was observed. In addition, assessments of earthquake and volcano parameters identified that earthquake fault characteristics increase the probability of triggered volcanic activity and variable response proportions at individual volcanoes and regionally demonstrated the critical role of the state of the volcanic system in determining if a volcano will respond. Despite the identification of these factors, this research was not able to define a model for the prediction of volcanic activity following earthquakes and, alternatively, proposed a process for response. In doing so, this thesis confirmed the potential use of earthquakes as a precursory indicator to volcanic activity and identified the most likely mechanisms that lead to seismically triggered volcanic unrest.
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McCormack, Thomas C. „A Methodology for Regional Seismic Damage Assessment and Retrofit Planning for Existing Buildings“. PDXScholar, 1996. https://pdxscholar.library.pdx.edu/open_access_etds/1239.
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Recent geologic research has shown that earthquakes more destructive than formerly expected are likely to occur in the Pacific Northwest. To mitigate catastrophic loss, planners are gathering information to make decision on implementing regional seismic retrofit programs. This research develops a model to estimate regional earthquake losses for existing buildings, and determine optimal retrofit priorities and budgets. Fragility curves are developed to provide earthquake damage estimates for a range of seismic intensities. The published earthquake damage estimates of a large group of prominent earthquake engineering experts are extended to include the combined effect of structure type, earthquake-sensitive variations in building design, site-specific soil conditions, and local seismic design practice. Building inventory data from a rapid visual screening survey of individual buildings form the basis for modeling structural variations. Earthquake Hazard Maps are the basis of modeling the effect on building damage of ground motion amplification, soil liquefaction, and slope instability. Published retrofit effectiveness estimates and retrofit cost data are used to estimate post-retrofit damage avoided, lives saved, and retrofit cost. A Building Classification System is formulated to aggregate buildings with similar retrofit benefit magnitudes. A cost-benefit analysis is used as the basis for a retrofit prioritization and efficiency analysis, to establish the cut-off point for an optimal retrofit program. Results from an Expected Value and a Scenario Earthquake Event are compared. Regional Earthquake Loss and Retrofit Analysis Program (REAL-RAP) software was developed, and used to make a loss estimate for more than 7,500 buildings inventoried in the 1993 Portland Seismic Hazards Survey. One hundred percent of the loss of life is attributed to only 10-percent of the buildings. A retrofit analysis is made for a Design Basis Earthquake. Twelve-percent of the building inventory was identified for the optimal retrofit program, wherein 98-percent of the loss of life is avoided at less than one-quarter the cost of retrofitting all the buildings. An alternate optimal retrofit program was determined using an Expected Value Analysis. Most of the buildings in the Design Basis Earthquake optimal retrofit program are also contained in the alternate program.
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Corbani, Silvia. „Análise dinâmica elasto-plástica de estruturas metálicas sujeitas a excitação aleatória de sismos“. Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/3/3144/tde-13032007-092337/.
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Ações sísmicas ocorrem com pouca freqüência e intensidade no Brasil, porém ocorrem em países da América Latina situados na costa do Pacífico e em Portugal, despertando o interesse da engenharia brasileira nesse assunto. Neste trabalho, apresenta-se um modelo numérico para análise de estruturas metálicas aporticadas planas com comportamento elasto-plástico sob excitação aleatória induzida por sismos. Para simular as vibrações aleatórias, utiliza-se uma simulação tipo Monte Carlo fundamentada no ?Vento Sintético?, proposta pelo Prof. Mário Franco. Nessa simulação, combinações de séries de carregamentos harmônicos são geradas com suas amplitudes extraídas de uma Função de Densidade Espectral de Potência (PSDF) das acelerações do solo e com ângulos de fase obtidos por um algoritmo pseudo-aleatório. A PSDF utilizada é um modelo reduzido do modelo Kanai-Tajimi que determina combinações de séries adimensionais, onde seus resultados para o trecho elástico são calibrados com o espectro de resposta elástica sugerido em norma internacional. A integração numérica passo-a-passo no domínio do tempo é feita para cada função de carregamento adotando-se o método de Newmark. O efeito elastoplástico é modelado pelo conceito de rótulas plásticas, assim, a cada passo é verificada a formação da rótula. Se certa seção atingir o momento fletor de plastificação, o valor do momento permanece constante e introduz-se uma rótula nessa seção com rigidez a flexão nula, permitindo rotações finitas livres. Em caso de reversão da direção do momento fletor, a rigidez elástica é integralmente recuperada com a eliminação da rótula do modelo. Ao final desse processo, obtém-se uma grande quantidade de dados de resposta. Faz-se um tratamento estatístico desses resultados de modo a concluir, do ponto de vista da engenharia, a probabilidade de ocorrência dos eventos. Para validar a metodologia proposta, analisou-se um edifício com cinco pavimentos. Os resultados satisfatórios foram obtidos quando comparados com exemplos da literatura, além de apresentarem-se estável com relação a integração no tempo.Seismic actions occur with low intensity and often in Brazil, however they occur in Latin-American countries on the Pacific Coast and in Portugal, arousing interest in this subject of the Brazilian engineering. In this work, a numerical model is presented for the analysis on the elastic-plastic behavior of steel planar framed structures under random seismic excitation. For random vibrations, a Monte Carlo type simulation is used. This simulation is based on the ?Synthetic Wind?, proposed by Prof. Mario Franco. In this simulation, combinations of series of harmonic loads are generated with their amplitude given by certain provided Power Spectrum Density Functions (PSDF) of ground acceleration and pseudorandomly set phase angles. The used PSDF is reduced model of the Kanai-Tajimi model that determine combinations of non-dimensional series whose results by the behavior elastic are adjusted by international codes Elastic Response Spectra. The step-by-step time integration is performed for each load function using the Newmark method. In order to model, the elastoplastic effect is used the plastic hinge concept. Therefore, at each step the hinge formation is verified. If a certain section reaches its full plastic bending moment, this value of moment is maintained and a hinge in that section is introduced in the model with null stiffness, allowing for free finite rotations. If the rotation in a certain hinged section is reversed, elastic behavior is restored by elimination of the hinge from the model. At the end of this process, a large quantity of response data is obtained. A statistic treatment of these results is performed, in the way that is possible conclude, from the engineering point of view, the probability of occurrence of these events. A statistic treatment based sound engineering conclusions is done for the happened probable events. In order to validate the proposed methodology, a five stories building is analyzed. Satisfactory agreement is obtained when compared to results from the literature, and the results are very stable with respect to the time integration.
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Filiatrault, Andre. „Seismic design of friction damped braced steel plane frames by energy methods“. Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28776.
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The investigation described in this thesis represents the first known attempt to develop a simplified method for the seismic design of structures equipped with a novel friction damping system. The system has been shown experimentally to perform very well and is an exciting development in earthquake resistant design. The design of a building equipped with the friction damping system is achieved by determining the optimum slip load distribution to minimize structural response.
A new efficient numerical modelling approach for the analysis and design of Friction Damped Braced Frames (FDBF) is presented. The hysteretic properties of the friction devices are derived theoretically and included in a Friction Damped Braced Frame Analysis Program (FDBFAP), which is adaptable to a microcomputer environment. The optimum slip load distribution is determined by minimizing a Relative Performance Index (RPI) derived from energy concepts.
The steady-state response of a single storey friction damped structure subjected to sinusoidal ground motion is investigated analytically. Basic design information on the optimum slip load for the friction device is obtained. The parameters governing the optimum slip load, which minimizes the amplitude for any forcing frequency, are derived. The study indicates that the optimum slip load depends on the characteristics of the ground motion and of the structure.
Using variational principles on a shear beam analogy, an optimum slip load distribution along the height of the structure is derived when the total amount of slip load is specified. It is shown that the optimum slip load is proportional to the slope of the deflected shape of the structure. The results of the study reveal that only a small improvement in the response is obtained by using this optimum distribution
compared to the response obtained with a uniform distribution. Therefore the use of an optimum uniform distribution seems adequate for the design of friction damped structures.
Taking into account the analytical results obtained, FDBFAP is then used in a parametric study which leads to the construction of a design slip load spectrum. The spectrum depends on the properties of the structure and ground motion anticipated at the construction site. It is believed that the availability of this design slip load spectrum will lead to a greater acceptance by the engineering profession of this new and innovative structural concept.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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Neurohr, Theresa. „The seismic vulnerability of art objects /“. Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99782.
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Throughout history, objects of art have been damaged and sometimes destroyed in earthquakes. Even though the importance of providing seismically adequate design for nonstructural components has received attention over the past decade, art objects in museums, either on display or in storage, require further research. The research reported in this study was undertaken to investigate the seismic vulnerability of art objects. Data for this research was gathered from three museums in Montreal.The seismic behaviour of three unrestrained display cases, storage shelves, and a 6m long dinosaur skeleton model structure was investigated according to the seismic hazard for Montreal and representative museum floor motions were simulated for that purpose. Particular attention was paid to the support conditions, the effects of modified floor surface conditions, the sliding and rocking response of unrestrained display cases, the location (floor elevation) of the display case and/or storage shelves, art object mass, and the dynamic properties of the display cases/storage shelves. The seismic vulnerability of art objects was evaluated based on the seismic response of the display cases/storage shelves at the level of art object display. The display cases were investigated experimentally using shake table testing. Computer analyses were used to simulate the seismic behaviour of storage shelves, and the seismic sensitivity of the dinosaur structure was determined via free vibration acceleration measurements. The floor contact conditions and floor elevation had a crucial effect on the unrestrained display cases, causing them to slide or rock vigorously. The distribution of content mass had a large impact on the response of the shelving system. As a result of experimental and analytical analyses, recommendations and/or simple mitigation techniques are provided to reduce the seismic vulnerability of objects of art.
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Castro, Cruz David Alejandro. „Prédiction des mouvements sismiques forts : apport de l’analyse du comportement non-linéaire des sols et de l’approche des fonctions de Green empiriques“. Thesis, Université Côte d'Azur (ComUE), 2018. http://www.theses.fr/2018AZUR4216/document.
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L'évaluation de l’aléa sismique doit tenir compte des différents aspects qui interviennent dans le processus sismique et qui affectent le mouvement du sol en surface. Ces aspects peuvent être classés en trois grandes catégories : 1) les effets de source liés au processus de rupture et à la libération d'énergie sur la faille. 2) les effets liés à la propagation de l'énergie sismique à l'intérieur de la Terre. 3) l'influence des caractéristiques géotechniques des couches peu profondes ; appelé effet de site. Les effets de site sont pris en compte dans la mitigation des risques par l'évaluation de la réponse sismique du sol. Lors de sollicitations cycliques, le sol présente un comportement non-linéaire, ce qui signifie que la réponse dépendra non seulement des paramètres du sol mais aussi des caractéristiques du mouvement sismique (amplitude, contenu en fréquence, durée, etc.). Pour estimer la réponse non-linéaire du site, la pratique habituelle consiste à utiliser des simulations numériques avec une analyse linéaire équivalente ou une approche non-linéaire complète. Dans ce document, nous étudions l'influence du comportement non-linéaire du sol sur la réponse du site sismique en analysant les enregistrements sismiques des configurations des réseaux de forages. Nous utilisons les données du réseau Kiban Kyoshin (KiK-Net). Les 688 sites sont tous équipés de deux accéléromètres à trois composantes, l'un situé à la surface et l'autre en profondeur. À partir de ces données, nous calculons les amplifications du mouvement du sol depuis la surface jusqu'aux enregistrements en fond de puit à l'aide des rapports spectraux de Fourier. Une comparaison entre le rapport spectral pour le faible et le fort mouvement du sol est alors réalisée. Le principal effet du comportement non-linéaire du sol sur la fonction de transfert du site est un déplacement de l'amplification vers les basses fréquences. Nous proposons une nouvelle méthodologie et un nouveau paramètre appelé fsp pour quantifier ces changements et étudier les effets non-linéaires. Ces travaux permettent d'établir une relation site-dépendante entre le paramètre fsp et le paramètre d'intensité du mouvement du sol. La méthode est testée sur les données accélérométriques du séisme de Kumamoto (Mw 7.1, 2016). Nous proposons ensuite d’utiliser des corrélations entre moment seismic et la duration de la faille (Courboulex et al., 2016), obtenues à partir d’une base de données globale de fonctions source et une méthode basée sur l’approche des fonctions de Green empiriques (EGF) stochastiques pour simuler les mouvements forts du sol dus à un futur séisme. Cette méthodologie est appliquée à la simulation d’un séisme de subduction en Équateur et comparée aux données réelles du séisme de Pedernales (Mw 7.8, 16 avril 2016) dans la ville de Quito. Nous proposons enfin de combiner la méthode de simulation de mouvements forts par EGF et la prise en compte des effets non-linéaires proposée dans les premiers chapitres. La méthode est testée sur les données accélérométriques d’une réplique du séisme de Tohoku (Mw 7.9)Seismic hazard assessments must consider different aspects that are involved in an earthquake process and affect the surface ground motion. Those aspects can be classified into three main kinds. 1) the source effects are related to the rupture process and the release of energy. 2) the path effects related to the propagation of energy inside Earth. 3) the influence of the shallow layers geotechnical characteristics; the so-called site-effects. The site effects are considered in risk mitigation through the evaluation of the seismic soil response. Under cyclic solicitations the soil shows a non-linear behavior, meaning that the response will not only depend on soil parameters but also on seismic motion input characteristics (amplitude, frequency content, duration, …). To estimate the non-linear site response, the usual practice is to use numerical simulations with equivalent linear analysis or truly non-linear time domain approach. In this document, we study the influence of the nonlinear soil behavior on the seismic site response by analyzing the earthquake recordings from borehole array configurations. We use the Kiban Kyoshin network (KiK-Net) data. All 688 sites are instrumented with two 3-components accelerometers, one located at the surface and the another at depth. From these data, we compute the ground motion amplifications from the surface to downhole recordings by the computing Fourier spectral ratios for the aim to compare between the spectral ratio for weak and strong ground motion. The main effect of the non-linear behavior of the soil on the site transfer function is a shift of the amplification towards lower frequencies. We propose a new methodology to quantify those changes and study the nonlinear effects. This work results in a site-dependent relationship between the changes in the site response and the intensity parameter of the ground motion. The method is tested analyzing the records of the earthquake of Kumamoto (Mw 7.1, 2016). Posteriorly, we propose to integrate a correlation between seismic moment and the duration of the fault (Courboulex et al., 2016) in the empirical Green’s function method. This methodology was applied to simulate one seduction event in Equator, and we compare the results with the records of the Pedernales earthquake (Mw 7.8, 2016) in the city of Quito. We attempt to take in account the nonlinear effects in the empirical Green’s function method. We use the methodologies of the first part of this document based on the frequency shift parameter. The procedure could be implemented in other methodologies that can predict an earthquake at a rock reference site, such as the stochastic methods. We test the procedure using the accelerometric records for one of the aftershocks o the Tôhoku earthquake (Mw 7.9)
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Bugeja, Michael. „Inelastic earthquake response of asymmetric structures“. Thesis, Queensland University of Technology, 1996. https://eprints.qut.edu.au/36027/1/36027_Bugeja_1996.pdf.
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This thesis presents a study into the inelastic earthquake response of asymmetric
structures. The study was conducted through the use of numerical simulation and
experimental testing. In particular, the study focussed on the effects of the torsional to
lateral frequency ratio, the stiffness eccentricity and strength eccentricity on structural
response.
Previous studies into this area have often drawn contradictory conclusions regarding the
effects of the various input parameters on structural response. It was concluded that
these differences arose from the use of different analytical models.
Structures responding to earthquake loading in a purely elastic fashion show an
amplification in torsional response when the torsional and lateral frequencies were close.
It was found that as more and more inelastic action was experienced by the structure
during loading, this amplification of the response was reduced.
It was also found that for a structure experiencing significant inelastic action during
earthquake loading the strength eccentricity is more important in determining structural
response. In most of the previous studies conducted, the strength eccentricity was not
considered as an independent structural parameter.
Experimental testing was conducted using a shaking table facility that was designed and
installed as part of this thesis. The results of these tests were in agreement with those of
the numerical study.
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Muthukumar, Susendar. „A Contact Element Approach with Hysteresis Damping for the Analysis and Design of Pounding in Bridges“. Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/5286.
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Earthquake ground motion can induce out-of-phase vibrations between adjacent structures due to differences in dynamic characteristics, which can result in impact or pounding of the structures if the at-rest separation is insufficient to accommodate the relative displacements. In bridges, seismic pounding between adjacent decks or between deck and abutment can result in localized deck damage, bearing failure, damage to shear keys and abutments, and even contribute to the collapse of bridge spans. This study investigates pounding in bridges from an analytical perspective. A simplified nonlinear model of a multiple-frame bridge is developed in MATLAB incorporating the effects of inelastic frame action, nonlinear hinge behavior and abutments. The equations of motion of the bridge response to longitudinal ground excitation are assembled and solved using the fourth-order Runge-Kutta method. Pounding is simulated using contact force-based models such as the linear spring, Kelvin and Hertz models, as well as the momentum-based stereomechanical method. In addition, a Hertz contact model with nonlinear damping (Hertzdamp model) is also introduced to model impact. The primary factors controlling the pounding response are identified as the frame period ratio, ground motion effective period ratio, restrainer stiffness ratio and frame ductility ratio. Pounding is most critical for highly out-of-phase frames. Impact models without energy dissipation overestimate the stiff system displacements by 15%-25% for highly out-of-phase, elastic systems experiencing moderate to strong ground excitation. The Hertzdamp model is found to be the most effective in representing impact. Traditional column hysteresis models such as the elasto-plastic and bilinear models underestimate the stiff system amplification and overestimate the flexible system amplification due to impact, when compared with stiffness and strength degrading models. Strength degradation and pounding are critical on the stiff system response to near field ground motions, for highly out-of-phase systems. Current design procedures are adequate in capturing the nonlinear hinge response when the bridge columns are elastic, but require revisions such as the introduction of time dependent reduction factors, and a frame design period to work for inelastic situations. Finally, a bilinear truss element with a gap is proposed for implementing energy dissipating impact models in commercial structural software.
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Paultre, Patrick. „Evaluation of seismic performance of concrete frame structures in Canada“. Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=75439.
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Three buildings in Montreal and three buildings in Vancouver were designed for different level of "ductility" according to the 1985 National Building Code of Canada and the 1984 Canadian Concrete Code.Three full scale reinforced concrete specimens representing an exterior beam-column-slab subassemblage of the Montreal structure were tested in order to determine the behaviour of these components. The role of the spandrel beam in limiting the effective slab width and its role in transferring shear to the joint region was investigated.
Analytical procedures were developed in order to predict the responses of main structural components to the combined loading effects of axial load, moment and shear. In addition a hysteretic behavioural model was developed in order to account for strength and stiffness degradation as well as pinching of the hysteretic response.
The analytical procedures were then used to model the responses of the components of these buildings. Non-linear dynamic analyses were carried out on each building for a series of artificially generated accelerograms. The results of the tests as well as the results of the non-linear dynamic analyses enabled an assessment of the performance of different building designs and an assessment of current code requirements.
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Kallros, Mikael Kaj. „An experimental investigation of the behaviour of connections in thin precast concrete panels under earthquake loading“. Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26707.
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Investigations of connections for precast concrete panel buildings have shown that it is difficult to design an embedded connection that will perform well under earthquake loading. Some typical connections use studs or reinforcing bars embedded in the edge of the panel. These are then welded or bolted to an adjacent panel. During earthquake loading the crushing of concrete around the embedment usually leads to premature loss of strength and stiffness of the connection before significant ductility can develop. It has been found that connection performance improves with increasing panel thickness.
The behaviour of embedded connections in thin precast concrete panels was investigated. The intent was to improve connection design details and to develop a simple method of predicting connection strengths with panel thicknesses of 50 mm to 75 mm.
Sixteen connections of six different types were tested. Three were tested monotonically and thirteen were tested under reversed cyclic loading.
Certain types of connections can be used to transfer earthquake loads between thin concrete panels as long as they have adequate strength. Methods for predicting the strength of connections are discussed. The connections tested should not be relied on to develop ductility.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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Bou, Nassif Aline. „Mouvements sismiques forts dans les régions montagneuses et mouvements de terrain induits“. Electronic Thesis or Diss., Université Grenoble Alpes, 2023. http://www.theses.fr/2023GRALU039.
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Après un séisme en zone de montagne, on observe fréquemment dans les zones proches de l'épicentre une grande variabilité dans la répartition spatiale des dommages, englobant à la fois les dommages structurels et les mouvements de terrain co-sismiques. Parmi d'autres facteurs, cette variabilité spatiale peut être en partie attribuée à l'amplification du mouvement sismique provoquée par la topographie. Bien que l'effet de la topographie ait été documenté depuis longtemps, il reste mal compris et est rarement considéré dans les normes de construction parasismique. Ma thèse est dédiée à la prédiction de l'amplification topographique du mouvement du sol à courte distance du séisme, et à l'étude de son impact sur les schémas de distribution spatiale des mouvements de terrain co-sismiques.Pour atteindre cet objectif, mon travail repose en premier lieu sur l'analyse par réseau neuronal de données synthétiques obtenues précédemment à partir de simulations 3D en différences finies de la propagation des ondes sismiques. Cette analyse vise à dériver un estimateur physique des effets de site topographique dans les zones proches de la source sismique. Ce proxy, que j’appelle i-FSC (illuminated Frequency Scaled Curvature), dépend de la longueur d'onde S, de la courbure de la surface topographique et d'un nouveau paramètre appelé « angle d'éclairage sismique normalisé », qui permet de quantifier l'exposition des pentes au champ d'onde sismique incident. Cet outil simple ne nécessite pas de ressources informatiques élevées ; il utilise seulement une carte numérique d'élévation de la surface et la position de la source sismique pour prédire les facteurs d'amplification en tout point de la surface topographique. Le proxy i-FSC permet d'explorer les variabilités dans l'amplification topographique des sites, causée par des sources sismiques proches. Cette avancée dans la prédiction de l'amplification topographique est particulièrement significative, car les zones les plus proches de la faille sont généralement les plus touchées pendant les séismes.Dans un second lieu, le proxy i-FSC est utilisé pour étudier la corrélation potentielle entre l'amplification topographique du mouvement sismique et la distribution spatiale des mouvements de terrain induits par des séismes tels que le séisme de Gorkha de 2015 (MW 7.8), le séisme de Kumamoto de 2016 (MW 7.1) et le séisme de Kaikōura de 2016 (MW 7.8). Les résultats montrent que les mouvements de terrain ont tendance à se localiser dans les zones amplifiées. Différents facteurs influençant le déclenchement des mouvements de terrain co-sismiques à différentes fréquences ont été identifiés. Aux basses fréquences, les mouvements de terrain ont tendance à se concentrer sur les pentes orientées en sens opposé à la source sismique (ayant des angles d'éclairage sismique plus élevés). À petite échelle spatiale, les localisations des mouvements de terrain correspondent aux zones d'amplification topographique à hautes fréquences, qui sont contrôlées par la courbure topographique. De plus, les mouvements de terrain ont tendance à se concentrer aux interfaces entre les pentes éclairées et non éclairées, ce qui peut indiquer des zones où la déformation de la pente est plus importante. Les résultats mettent également en évidence l'importance fondamentale de prendre en compte l'effet de l'amplification topographique, simplement dérivé par le proxy i-FSC, en conjonction avec d'autres facteurs classiques tels que la raideur des pentes, pour une meilleure compréhension des mécanismes complexes qui régissent la distribution spatiale des mouvements de terrain co-sismiques aux échelles locales et régionales.Les résultats de cette étude revêtent une grande importance, car ils pourraient orienter des recherches futures visant à élaborer des stratégies plus efficaces d'évaluation et de réduction des risques dans les régions montagneusesDuring an earthquake, a high degree of variability in damage distribution, encompassing both structural damage and co-seismic landslides, is commonly observed in mountainous regions near the seismic source. Among other factors, this spatial variability can be partly attributed to the amplification of seismic waves caused by surface topography. While this effect has long been documented, it remains poorly understood and is rarely incorporated into building specification codes. My thesis is dedicated to predicting the amplification of ground motion caused by surface topography in close distances to an earthquake, and studying its potential impact on co-seismic landslides distribution patterns.To achieve this goal, my work initially relies on neural network analysis of previously-available synthetic data obtained from 3D finite-differences simulations of seismic wave propagation. This analysis aims to derive a physics-based estimator of topographic site effects in close distances to the source. This proxy, which I refer to as the i-FSC proxy (illuminated Frequency Scaled Curvature), depends on the S-wavelength, the curvature of the topographic surface, and a new parameter called the “normalized seismic illumination angle” which quantifies the slope's exposure to the incoming wavefield. This user-friendly tool does not require high computational resources; it only uses a digital elevation map and the position of the seismic source to predict amplification factors at any point of the surface topography. The i-FSC allows exploring the variations in topographic amplification influenced by nearby seismic sources. This advancement is particularly significant as the areas closest to the fault are typically the ones most severely affected during earthquakes.Subsequently, the i-FSC proxy is employed to investigate the correlation between ground motion amplification and the spatial distribution of earthquake-induced landslides triggered by events such as the 2015 Gorkha earthquake (MW 7.8), the 2016 Kumamoto earthquake (MW 7.1), and the 2016 Kaikōura earthquake (MW 7.8). The results indicate that co-seismic landslides tend to be localized in amplified areas. Different controls on the landslide triggering at different frequencies have been identified. At lower frequencies, landslides tend to concentrate on slopes facing away from the seismic source (with higher seismic illumination angles). At smaller scales, the location of landslides mimics the amplification maps at higher frequencies, which are primarily influenced by surface topography curvature. Furthermore, landslides appear to also cluster at the interfaces between illuminated and non-illuminated slopes, which may indicate areas where slope deformation is the greatest. The results also highlight the crucial importance of considering the effect of topographic amplification, simply derived by the i-FSC proxy, together with other classic factors such as slope steepness, for a better understanding of the complex mechanisms governing the spatial distribution of earthquake-induced landslides at local and regional scales.The results of this study hold significant importance, as they could guide future research efforts aimed at developing more effective risk assessment and mitigation strategies in mountainous regions
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Yung, Willy Chi Wai. „Innovative energy dissipating system for earthquake design and retrofit of timber structures“. Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/30128.
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This thesis presents the results obtained from a preliminary investigation into the potential application of the friction damping concept to wood structures to improve their seismic response. Sliding friction devices which contain heavy duty brake lining pads have been proposed in order to enhance a wood structure's seismic performance. The devices are mounted onto a structure's shearwalls to dissipate seismic energy input during the wall's deformation in an earthquake.
Prototypes of the four friction damping devices were tested to examine their hysteretic behaviour. Conventional full scale, 2.44 x 2.44 m (8 x 8 ft) timber shearwalls, typical of ones used in residential and light-commercial building applications, and ones retrofitted with the friction damping devices were tested on a shake table. Three set of tests were conducted. They involved loading the walls under unidirectional racking, static-cyclic and simulated earthquake loads. Test results from the two types of shearwalls were compared against each other and against the findings from the computer programs SADT and FRICWALL. SADT is a finite elements program which computes the load-deformation behaviour of shearwalls. FRICWALL is an inelastic time-history dynamic model which computes the response time-history of a shearwall under a simulated seismic event.
The cyclic tests of the friction damping devices showed that they exhibited very stable and non-deteriorating hysteretic behaviour. The shake table tests of the full scale timber
shearwalls showed that the friction damped walls were stiffer, can sustain an average of 23.7 % higher racking load and dissipate an average of 42.9 % more energy than the conventional ones before a ductile failure. Failure in the conventional walls was brittle. These results were in agreement with the SADT findings. Under slow cyclic loads, they dissipated more energy, but because their overall hysteretic behaviour was still pinched, they were just as inefficient as the conventional walls at dissipating energy. On the average, their seismic performance was only marginally better than that of the conventional wall, with an average drop of 9.6 % in peak wall deflection. This is far short of the average of 29.5 % computed by FRICWALL. Detailed analysis of the results show that due to bending in the framing members of the shearwall, the load necessary to cause slippage of the friction devices was not achieved until wall deflections in the order of 25.4 mm (1.0 in) was reached. Since only at the peak or near-peak excitation levels of an earthquake did shearwall deflections surpass this magnitude, the devices were not able to contribute to the energy dissipation of the shearwalls during the majority portion of a seismic event.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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Malyszko, Thomas E. „The nonlinear response of reinforced concrete coupling slabs in earthquake-resisting shearwall structures /“. Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66183.
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Sheikh, MD Neaz. „Seismic assessment of buildings in Hong Kong with special emphasis on displacement-based approaches“. Thesis, Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B31456662.
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Parmar, Surinder Singh. „2-D non-linear seismic analysis of one-storey eccentric precast concrete buildings“. Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26728.
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Investigations into the behaviour of precast buildings under earthquake loading have shown that the connections are likely to be the weakest link in a pre-cast structure, and the stability of the structure under earthquake loading depends upon the strength & stability of these connections. A 2-dimensional non-linear dynamic analysis of a one storey box-type pre-cast buildings is presented. The shear walls in the buildings are modelled by linear springs, the properties of which depend upon the connections connecting the rigid panels of the shear walls.
To check the effectiveness of the NBCC code design, computer studies have been made on a box-type building statically designed for different eccentricities. The strength of the shear walls was calculated assuming that each panel was a cantilever fixed at the base with dowel bars providing the flexural steel. To make the building survive a major earthquake, we need dowel connections that can take 5mm to 6mm elongation which can be easily accommodated. Studies have also shown that under the action of an earthquake, the response of a highly unsymmetrical building will not be very different from that of a symmetric building as long as the building is properly designed using the NBCC code provisions for earthquake loading. It has also been shown that the NBCC code design eccentricity equation is somewhat conservative in calculating the design eccentricity and that a small change in the stiffness of walls perpendicular to the direction of earthquake has little effect on the response of the structures.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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Loots, Jurie. „Computational assessment of seismic resistance of RC framed buildings with masonry infill“. Thesis, Stellenbosch : Stellenbosch University, 2005. http://hdl.handle.net/10019.1/50299.
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Thesis (MScIng)--Stellenbosch University, 2005.Some digitised pages may appear illegible due to the condition of the original hard copy.
ENGLISH ABSTRACT: Reinforced concrete (RC) frames with unreinforced masonry infill form the structural system of many buildings and this is also true for South Africa. It is common practice to consider the masonry infill as a non-structural component and therefore it does not contribute to the performance of the Re frame buildings under lateral loading such as earthquake loading. This is done by leaving a sufficient gap between the Re frame and the infill. This ensures that there is no contact between the frame and the infill during an earthquake event. However, it has been suggested that masonry infill can play a significant role in the performance of a Re frame building under lateral loading. The first part of the study focuses on the South African situation. The relevance of shear walls in these Re frame buildings as well as the size of the gap (between frame and infill) left in practice, are investigated. This is done by finite element analysis. The second part of the study focuses on the effects that the infill can have on the global performance of the structure when there is full contact between the Re frames and infill. The effect of openings in the infill to the response of the frame is also investigated. Finite element models of single span Re frames with infill is built and analyzed in order to investigate possible damage to the infill, frame infill interaction and to obtain the non linear stiffness of the frame with infill as a whole. This obtained non linear stiffness can be modelled in Diana as a non linear spring that will be used in the development of a simplified analysis method. The simplified method developed consists of a frame and two such non linear springs, placed diagonally, and which have the same force versus displacement behaviour as the original frame with infill. These single span frames can be added together to model a whole frame. In a first step to generalise the simplified method, various geometries of infills are considered, varying span and height, as well as opening percentage, representing windows and doors of varying total area and positioning. However, in this study a single masonry type, namely solid baked clay bricks set in a general mortar, is considered. To generalise the approach further, other masonry types can be considered in the same way. The use of these springs in a simplified model saves computational time and this means that larger structures can be modelled in Diana to investigate response of'Rf' frame buildings with infill. The work reported in this thesis considers only in-plane action. Out-of-plane-action of the masonry infill has been reported in the literature to be considerable, under the condition that it is sufficiently tied to the frame to prevent mere toppling over, causing life risking hazards in earthquake events. This matter should be studied in continuation of the current research to generalise the simple approach to three dimensions.
AFRIKAANSE OPSOMMING: Gewapende betonrame (GBR-e) met ongewapende messelwerk invulpanele (invul) vorm die strukturele ruggraat van vele geboue en dit geld ook vir geboue in Suid-Afrika. Dit is algemene praktyk om die invulpaneel in sulke geboue as 'n nie-strukturele komponent te beskou. Daarvolgens dra dit nie by tot die gedrag van 'n GBR gebou onderhewig aan 'n aarbewing nie. Dit word bereik deur 'n groot genoeg gaping tussen die betonraam en die invul te los. Die gevolg is dat daar geen kontak tussen die betonraam en die invul plaasvind indien daar 'n aardbewing sou voorkom nie. Dit is egter voorgestel dat invul 'n noemenswaardige rol kan speel in die gedrag van 'n GBR gebou onderwerp aan 'n horisontale las. Die eerste deel van die studie fokus op die Suid-Afrikaanse situasie. Die relavansie van skuifmure in GBR geboue asook die grootte van die gaping (tussen die raam en invul) wat in die praktyk gebruik word, word ondersoek. Dit word gedoen met behulp van eindige element analises. Die tweede deel van die studie fokus op die effek wat invul kan hê op die globale gedrag van 'n struktuur wanneer daar volle kontak tussen die GBR en die invul is. Die effek wat die teenwoordigheid van openinge in die invul kan hê op die gedrag van 'n GBR is ook ondersoek. Eindige element modelle van enkelspan GBR met invul is gemodelleer en geanaliseer om die moontlike skade aan die invul, die interaksie tussen die GBR en die invul asook die nie-lineêre styfheid van die raam en invul as 'n geheel, te ondersoek. Hierdie nielineêre styfheid kan in Diana as 'n nie-lineêre veer gemodelleer word en word gebruik in die ontwikkeling van 'n vereenvoudigde metode. Hierdie vereenvoudigde metode wat ontwikkel is, bestaan uit 'n raam en twee sulke nielineêre vere (diagonaal geplaas). Die raam met vere het dieselfde krag teenoor verplasingsgedrag as die van die oorspronklike raam met invul wat dit voorstel. Hierdie rame kan saamgevoeg word om 'n raam uit 'n gebou as 'n geheel te modelleer. Verskeie invul geometrieë word gebruik in die analises in 'n eerste stap om die vereenvoudigde metode te veralgemeen. Die span en hoogte asook opening persentasie van die invul word gevariëer om vensters en deure van veskeie grootte en posisie voor te stel. In die studie, 'n enkel messelwerk tipe, naamlik solied klei bakstene geset in algemene mortar, word gebruik. Ander messelwerk tipes kan gebruik word om die metode verder te veralgemeen. Die gebruik van die vere in die vereenvoudigde metode spaar berekenings tyd en dit beteken dat groter strukture in Diana gemodelleer kan word om die gedrag van GBR geboue met invul te ondersoek. Die werk gedoen in die tesis neem slegs in-vlak aksie in ag. Literatuurstudie dui daarop dat goeie uit-vlak-aksie van messelwerk invul bestaan, mits dit goed geanker is aan die raam om te verseker dat dit nie kan omval en 'n gevaar vir lewens in 'n aardbewing inhou nie. Dit behoort verder bestudeer te vord in die vervolging van die huidige ondersoek om die vereenvoudige metode na drie dimensies te veralgemeen.
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Luettich, Scott M. „Subsidence approach to risk of damage in earthquake-induced liquefaction“. Thesis, Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/20160.
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Wong, Sze-man, und 黃思敏. „Seismic performance of reinforced concrete wall structures under high axial load with particular application to low-to moderate seismicregions“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B34739531.
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Issa, Camille Amine. „Nonlinear earthquake analysis of wall pier bridges“. Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/54297.
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Accurately predicting the response of complex bridge structures to strong earthquake ground motion requires the use of sophisticated nonlinear dynamic analysis computer programs not generally available to the bridge design engineer. The analytical tools that have been developed are generally applicable to bridges whose substructures can be idealized as beam-columns. Bridges with wall piers do not belong to this category
The major objective of this study is to develop an analysis tool capable of simulating the effects of earthquakes on monolithic concrete wall pier bridges. Thus, after surveying the literature, a mathematical model is developed for the geometrically nonlinear earthquake analysis of wall pier bridges. Mixed plate elements are used to model the wall pier. The plate element has eight nodes and the degrees of freedom per node are three displacements and three moments. Beam elements are used to model the bridge deck. The beam element accounts for shear deformation and it has two nodes with three displacements and three rotations as degrees of freedom per node. A transitional element is used to join the beam elements to the plate elements. The equation of dynamic equilibrium is solved using the Newmark method with modified Newton-Raphson type iteration at each time step.
The mixed plate element is used to model two plate structures and the results are compared with analytical and other finite element solutions. A two span wall pier bridge is modeled using the structural elements developed in this study. The digitized time history for the N-S component of the El Centro Earthquake of May 18, 1940, is used to seismically excite the bridge model.Ph. D.
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Lee, Jimin. „Earthquake site effect modeling in sedimentary basins using a 3-D indirect boundary element-fast multipole method“. Diss., Online access via UMI:, 2007.
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Malushte, Sanjeev R. „Prediction of seismic design response spectra using ground characteristics“. Thesis, Virginia Tech, 1987. http://hdl.handle.net/10919/45802.
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The available earthquake records are classified into five groups according to their site stiffness and epicentral distance as the grouping parameters. For the groups thus defined, normalized response spectra are obtained for single-degree-ofâ freedom and massless oscillators. The effectiveness of the grouping scheme is examined by studying the variance of response quantities within each group. The implicit parameters of average frequency and significant duration are obtained for each group and their effect on the response spectra is studied. Correlation analyses between various ground motion characteristics such as peak displacement, velocity, acceleration and root mean square acceleration are carried out for each group.
Smoothed design spectra for relative and pseudo velocities and relative acceleration responses of single degree of freedom oscillators and the velocity and acceleration responses of massless oscillators are proposed for each group. Methods to predict relative velocity and relative acceleration spectra directly from the pseudo velocity spectra are presented. It is shown that the relative spectra can be reliably estimated from the pseudo spectra. The site dependent design spectra are defined for a wide range of oscillator periods and damping ratios.
Master of Science