Scour is a process of removing soils around foundations by currents and waves. For the pile-supported marine structures such as the monopile-supported offshore wind turbines (OWTs) and the pile-supported bridges, scour can decrease the pile capacities and alter the dynamic responses of the structures. At present, there is not a widely accepted method to estimate pile axial or lateral capacity under scoured conditions. For example, different recommendations are used among the existing design standards for estimation of the vertical effective stress and the resulting capacities for single piles under different scour conditions. None of the existing standards or design practice has even considered the scour effects on the behavior of pile groups. Furthermore, the investigation into the responses of piles under multiple hazards of scour and earthquakes is rarely reported. To address the foregoing limitations, this study first introduces an analytical solution to determining the vertical effective stress of soils around single isolated piles under scoured conditions and uses it to examine the limitations of the existing standards in estimation of pile tensile capacity (Chapter 1). The effect of soil-pile interface friction is highlighted. Next, the study proposes new approaches to investigating the combined effects of scour and earthquakes on the lateral responses of the monopile-supported OWTs in sand (Chapter 2) and soft clay (Chapter 3). Lastly, simple and practical methods are developed based on the p-y curve framework for analyzing the lateral responses of pile groups in sand (Chapter 4) and soft clay (Chapter 5) subjected to static lateral loading. The proposed methods in this study were encoded into a series of open-source computer scripts for engineering practice. They were verified with the 3D continuum finite element (FE) analyses. Using the proposed methods, standard methods, and 3D FE method, parametric analyses were conducted to investigate the scour effects on the lateral behavior of the monopile-supported OWTs under crustal earthquakes and that of the pile groups under static loading. The factors considered in the parametric study included effects of scour-hole dimensions, soil stress history, soil density, soil-pile interface behavior, soil liquefaction potential, pile group configurations, etc. Through the parametric analyses, the standard methods were critically assessed by comparing the results to those calculated by the proposed methods and 3D FE methods, and some design-related issues were also discussed. / Graduate

This thesis deals with the possibility of using the residual shape with help of the structural analysis software SCIA Engineer in the calculation of seismic load. Residual shape will be used in combination with CQC and SRSS calculation method, including different numbers of own shapes and the oscillated mass. In the last step, the results will be compared with each other.

Das Bodenverhalten unter dynamischer Beanspruchung ist sehr komplex, wird jedoch in der Praxis häufig mit Hilfe von vereinfachten Modellen abgebildet. Die Gültigkeit solcher Modelle ist jedoch aufgrund des spannungs- und dehnungsabhängigen Bodenverhaltens sehr begrenzt. Alternativ dazu bieten sich dynamische numerische Berechnungen mit fortgeschrittenen Stofmodellen, die das Bodenverhalten in einem großen Dehnungs- und Spannungsbereich realitätsnah repräsentieren können. In dieser Arbeit wurde untersucht, inwieweit sich das komplexe Bodenverhalten unter dynamischen Einwirkungen mit Hilfe der Hypoplastizität abbilden lässt. Dabei wurde die entscheidende Rolle der Parameterermittlung veranschaulicht und zusätzlich ein angemessener Vorgang zur Bodenparameterbestimmung beschrieben. Zunächst wurde das Verhalten einer trockenen Sandschicht infolge von Erdbebenbeanspruchungen numerisch untersucht. Die Ergebnisse der Berechnungen zeigen, dass die Beschleunigungsamplifikation in der Nähe zur Bodenoberfläche von der Frequenz und der Amplitude der Grundbeschleunigung abhängt. Weiterhin nimmt die berechnete Eigenfrequenz und die entsprechende Amplifikation mit zunehmender Beschleunigungsamplitude ab. Des Weiteren wurde ein Zentrifugenversuch an einem im Sand eingebeteten Tunnel unter Erdbebeneinwirkungen nachgerechnet. Die berechneten Ergebnisse zeigen eine ausreichende Übereinstimmung mit dem Experiment. Mit der numerischen Nachrechnung wurde auch eine Abhängigkeit zwischen den Änderungen der Biegemomente in der Tunnelschale und der Oberflächensetzung im umliegenden Boden festgestellt. Die Standsicherheit von Böschungen unter Erdbebenbeanspruchungen stellt wegen des komplexen Bodenverhaltens eine weitere Herausforderung für die Berechnungen dar. Zunächst wurde überprüft, inwieweit sich das Böschungsverhalten mit der in der Praxis häufig eingesetzten pseudo-statischen Methode abbilden lässt. Hierfür wurde für eine in der Zentrifuge untersuchte Modellböschung die pseudostatische Analyse durchgeführt. Die im Zentrifugenversuch aufgetretenen oberflächennahen Gleitfläche lässt sich durch die pseudo-statische Methode nicht prognostizieren. Für eine oberflächennahe Gleitfläche wurde hingegen ein sehr hoher Standsicherheitsfaktor ermittelt. Mit einer numerischen Nachrechnung mit einem hypoplastischen Stoffmodell mit Betrachtung der intergranularen Dehnungen konnte das Verhalten der Modellböschung qualitativ und quantitativ sehr gut abgebildet werden. Somit wurden sowohl die oberflächennahe Gleitfläche als auch die Vertikal- und Horizontalverschiebungen realitätsnah wiedergegeben. In dieser Arbeit wurde des Weiteren ein Vorgang als Kombination zwischen den dynamischen numerischen Berechnungen und der pseudo-statischen Methode zur Bewertung der Standsicherheit von Böschungen unter dynamischer Einwirkung vorgeschlagen. Damit ließ sich ebenso ein realitätsnäher Stansicherheitsfaktor ermitteln. Da die Anwendung der pseudo-statischen Methode bei den Böschungen aus wassergesättigten kohäsionslosen Böden problematisch ist, lassen sich solche Böschungen entweder mit Zentrifugenmodellen oder numerisch mit fortgeschrittenen Stoffmodellen untersuchen. In dieser Arbeit wurden Nachrechnungen von Zentrifugenversuchen durchgeführt. Es handelt sich um einen Erddamm aus einem wassergesättigten, dicht gelagerten Nevada Sand unter Erdbebeneinwirkung. Mit der numerischen Berechnung wurde das Dammverhalten qualitativ und quantitativ sehr gut abgebildet. Sowohl die Dammverschiebungen als auch der Aufbau des Porenwasserdrucks zeigen eine sehr gute Übereinstimmung mit den Messungen. Weiterhin wurden mit den gleichen Bodenparametern zwei weitere Zentrifugenversuche unter Erdbebeneinwirkung nachgerechnet. Beide Modellversuche wurden mit einem locker gelagerten, wassergesättigten Nevada Sand durchgeführt. Bei einem Versuch wurde ein Erddamm und bei dem anderen eine Sandschicht untersucht. In den numerischen Nachrechnungen ließen sich sowohl die Verschiebungen als auch die Porenwasserdrücke in beiden Randwertproblemen realistisch abbilden. Weiterhin wurde die Wirkung von Schottersäulen zur Verhinderung der Bodenverflüssigung numerisch untersucht. Zunächst wurden die Dränage- und die Aussteifungswirkung der Schottersäulen unabhängig voneinander betrachtet. Die Dränagewirkung ist vernachlässigbar, da sich während eines Erdbebens der Porenwasserdruck sehr schnell aufbaut. Wegen der hohen Steifigkeit der Schottersäulen wird zwar weniger Porenwasserdruck in den Boden aufgebaut. Die effektive Spannung nimmt jedoch trotzdem unverhindert ab. Dies lässt sich damit begründen, dass die hohe Säulensteifigkeit zu einer Spannungsumlagerung in Richtung Säulen führt und ein Siloeffekt entsteht. Somit wird der Boden zum Teil von den Säulen getragen und die totale Spannung im Boden nimmt ab. In der 3D-Berechnungen ist dieser Siloeffekt deutlich geringer als in den 2D-Berechnungen. Nichtsdestotrotz zeigen sowohl die 2D- als auch die 3D-Berechnungen, dass die Säulensteifigkeit eine nur mäßige Wirkung zur Verhinderung der Bodenverflüssigung aufweist. In weiteren 3D-Berechnungen wurde der Einfluss der Säulenherstellung untersucht. Hierfür wurden Berechnungen mit erhöhter Bodendichte und Seitenspannung durchgeführt. Sowohl die Verdichtung als auch die Erhöhung der Seitenspannung verlangsamen den Porenwasserdruckaufbau bzw. die Abnahme der effektiven Spannung. Der Einfluss der Bodenverdichtung ist jedoch wesentlich höher. Weiterhin weist die Wirkung der Schottersäulen eine Abhängigkeit von der dynamischen Belastung auf. Die Bodenverflüssigung infolge eines kleinen Erdbebens wird verhindert, während sich die Verflüssigung infolge eines stärkeren Erdbebens nur um wenige Sekunden verzögert. / The soil behavior under dynamic loading is very complex. However, in daily use it is often illustrated by means of simplified models. The validity of these models is very limited due to the stress and strain-dependent soil behavior. Alternatively, dynamic numerical calculations can be performed with advanced constitutive models which can represent soil behavior in a wide range of strain and stress. In this work it was investigated, to which extent the complex soil behavior can be reproduced using hypoplasticity.Furthermore,the important role of parameter determination was illustrated. In addition, an appropriate procedure for determining soil parameters was described. First, the behavior of a dry sand layer under earthquake load was investigated numerically. The results of the calculations show that the acceleration amplification near the ground surface depends on the frequency and the amplitude of the basic acceleration. Furthermore, the calculated natural frequency and the corresponding amplification decrease with increasing acceleration amplitude. In addition, a centrifuge test on a tunnel embedded in sand under earthquake effects was numerically calculated. The calculated results show a satisfactory agreement with the experiment. The numerical calculation also revealed a dependency between the changes in the bending moments in the tunnel lining and the surface settlement of the surrounding soil. Due to the complex soil behavior, the stability of slopes under earthquake loads poses a further challenge for the calculations. Firstly, it was examined, to which extent slope behavior can be represented with the frequently used pseudo-static method. For this purpose the pseudo-static analysis was carried out for a model earth dam examined in the centrifuge. The pseudo-static method predicts a deep seated sliding surface in contrast to the shallow sliding surface in the centrifuge test. However, for a shallow sliding surface, a very high stability safety factor was determined. With a numerical calculation using a hypoplastic material model considering the intergranular strains, the behavior of the earth dam could be reproduced qualitatively and quantitatively very well. Thus, the shallow sliding surface as well as the vertical and horizontal displacements were reproduced realistically. In this thesis, a combination of the dynamic numerical calculation and the pseudo-static method for assessing the stability of slopes under dynamic influence was proposed. So, a realistic stability safety factor can be determined. The application of the pseudo-static method is problematic in case of slopes in saturated non-cohesive soil. These slopes can either be investigated with centrifuge models or numerically with advanced material models. In this work, numerical recalculations of centrifuge tests were carried out. It is an earth dam from a saturated Nevada sand under an earthquake effect. With the numerical calculation the dam behavior was reproduced qualitatively and quantitatively in a satisfactory manner. Both the dam displacements as well as the build-up of pore water pressure show a very good agreement with the measurements. Two further centrifuge tests were also carried out using the same soil parameters. Both model tests were conducted with a loose saturated Nevada sand. One test was carried out on an earth dam and the other on a sand layer. With the numerical calculations, both displacements and pore water pressures were reproduced realistically in both boundary value problems. In addition the effect of stone columns to prevent soil liquefaction was studied numerically. First, the drainage and stiffening effects of stone columns were examined separately. The drainage effect has no significant influence because of the very rapid build-up of pore water pressure during the earthquake. Due to the high stiffness of the stone columns, less pore water pressure builds up in the soil. However, the effective stress continues to decrease unhindered. The high stiffness of the columns leads to a stress redistribution in the direction of the columns and a silo effect arises. In 3D calculations, the silo effect is significantly lower than in 2D calculations. The 2D and 3D calculations show that the column stiffness has a moderate effect to prevent soil liquefaction. In further 3D calculations, the influence of column installation was investigated. Calculations with increased soil density and lateral stress were carried out for this purpose. Both the compaction and the increase of the lateral stress slow down the build-up of pore water pressure and the decrease in effective stress. However, the impact of soil compaction is much higher. Furthermore, the effect of stone columns depends on the dynamic load. The soil liquefaction due to a small earthquake is prevented, while liquefaction due to a stronger earthquake is delayed only by a few seconds.

Das seitliche Kraftwiderstandssystem, in diesem Fall Stahlbetonkernwände eines 10-stöckigen Gebäudes, das aus Schwerkraftstützen und Scherwänden besteht, wurde linear (unter der Annahme eines linearen elastischen Materialverhaltens von Beton) und nichtlinear gerissen (unter Berücksichtigung des Materialverhaltens von Beton) unter seismische Belastung analysiert. Erst wurde die grundlegenden Methode der äquivalenten Seitenkraft zur Schätzung der seismischen Belastungen benutzt, später wurde die aktuelle Methode The Performance Based Seismic Design verwendet, bei der reale seismische Aufzeichnungen verwendet werden und die Beschleunigungen mithilfe der Software ETABS auf das Gebäude angewendet werden. Nach dem Anwenden der Beschleunigungen wurden die maximal resultierenden Kräfte und Verformungen bewertet. Das Gebäude wurde dann für die maximal resultierenden Kräfte ausgelegt.Der Inhalt des Hauptberichts ist: - Allgemeine Beschreibung des Gebäudes, seismische Standortinformationen, Standortantwortspektren, Belastung und seismische Kräfte einschließlich Analyse des modalen Antwortspektrums. - Lineares Design des Modells für Schwerkraft und seismische Belastungen, P-M-Wechselwirkungsdiagramme für den U-Querschnitt aus Stahlbeton, Entwurf einer Längs- und Schubbewehrung der Scherwände und des Koppelbalkens. - Zwei Varianten des nichtlinearen Modells, bei denen die Kernwand (Scherwände) gemäß jeder Variante entworfen wird, wobei der Einfluss des Dämpfungsmodells auf das nichtlineare dynamische Verhalten sowie der Einfluss des Kopplungsstrahlmodells auf das nichtlineare dynamische Verhalten untersucht werden. - Entwurfsüberprüfung, erst mit der Definition der Leistungsobjekte und Modell für die Zeitverlaufsanalyse. Es wurden zwei Leistungsziele untersucht: Vollbetriebs- und Lebenssicherheitsprüfungen. - In zwei Fällen wurde eine zusätzliche Studie zur Reaktion von nicht strukturellen Elementen aufgrund seismischer Belastung durchgeführt: Überprüfung des Vollbetriebs und der Lebenssicherheit. - Die Durchsetzungszeichnungen wurden fertiggestellt und dem Bericht beigefügt. Schlussfolgerung und Empfehlungen waren am Ende des Berichts. Dies ist wichtig für die Gesellschaft, da die verwendete Methode für die seismische Planung jedes Gebäudes verwendet werden kann. Es könnte ein Holzbau oder ein Mauerwerk sein. Die Gestaltung eines Mauerwerksgehäuses wird Gegenstand eines zukünftigen Forschungsprojekts sein. Allgemeine Ziele: Lineare und nichtlineare seismische Bemessung von Stahlbetongebäuden unter Verwendung der 'seismischen Bemessung der Leistungsgrundlagen:Acknowledgement 4 PART I: General Information, Site and Loading 5 1. General Information About the Building 5 1.1. Specified Material Properties: 6 1.2. Site Information: 6 1.3. Geometry (Figure I.1): 7 2. Site Seismicity and Design Coefficients 7 2.1. USGS Results 7 2.2. Site Response Spectra 8 2.3. Design Coefficients And Factors For Seismic Force-Resisting Systems 8 3. Loading 9 3.1. Determination Of Seismic Forces 9 3.2. Modal Response Spectrum Analysis 9 3.3. Seismic Load Effects And Combinations 11 PART II: Core Wall Design - Linear Model 12 4. Model of ETABS 12 4.1. Geometry 12 4.2. Gravity Loads 13 4.3. Seismic Loads 15 4.4. Tabulated Selected Results From ETABS Analysis 16 5. P-M Interaction Diagrams 17 5.1. N-S Direction 17 5.2. E-W Direction 19 6. Lateral Force Resisting System, Linear 20 6.1. Longitudinal Reinforcement 20 6.2. Shear Reinforcement 22 6.3. Boundary Elements 24 6.3.1. Transverse Reinforcement Of Boundary Elements 26 6.4. Coupling Beams 27 7. Detailing 30 PART III: Site Response Spectra and Input Ground Motions 31 8. Performance Levels 31 8.1. ASCE 7-16 Target Spectra 31 8.2. Site Response Spectra 34 8.2.1. Ground Motion Conditioning 34 8.2.2. Amplitude Scaling 37 8.2.3. Pseudo Acceleration and Displacement Response Spectra 38 PART IV: Non-Linear Model 40 9. Variant 1 of Non-Linear Model 40 9.1. Complete Core Wall Design for Combined Axial-Flexure 40 9.2. Modal Analysis 43 9.3. Influence of the Damping Model on the Nonlinear Dynamic Response 49 10. Variant 2 of Non-Linear Model 57 10.1. Influence of the Coupling Beam Model on the Nonlinear Dynamic Response 57 10.2. Estimated Roof Displacement 68 PART V: Design Verification 70 11. General 70 11.1. Performance Objectives 70 11.2. Model For Time-History Analyses 71 11.3. Performance Level Verification 71 11.4. Fully Operational Performance Level Verification 71 11.5. Life Safety Performance Level Verification 78 PART VI: Capacity Design of Force Controlled Elements and Regions and Design of Acceleration-Sensitive Nonstructural Elements 87 12. General 87 12.1. Design Verification 87 12.1.1. Full Occupancy Case 87 12.1.2. Life Safety Case 91 12.1.3. Observations on Plots 93 12.2. Acceleration response spectra at roof level 94 12.2.1. Observations on Plots 95 12.3. Core Wall 97 12.4. Design Detail Comparison 103 12.5. Detailed Drawing 103 12.6. Diaphragm 104 12.7. Fire Sprinkler System 117 12.8. Overhanging Projector 119 PART VII: Conclusion 122 / Lateral Force Resisting System, in this case reinforced concrete core walls of a 10 story building consists of gravity columns and shear walls, has been analyzed in linear (assuming linear elastic material behavior of concrete) and nonlinear cracked (considering plastic material behavior of concrete) case, for seismic loading. Starting with the basic method of equivalent lateral force to estimate the seismic loads, then using the up to date method, The Performance Based Seismic Design, which uses real seismic records and apply the accelerations on the building using the software ETABS. After applying the accelerations, maximum resulted forces and deformations have been evaluated. The building then have been designed for the maximum resulted forces. The contents of the main report are: - General description of the building, site seismic information, site response spectra, loading and seismic forces including modal response spectrum analysis. - Linear design of the model for gravity and seismic loads, P-M interaction diagrams developed for U cross section from reinforced concrete, designing longitudinal and shear reinforcement of the shear walls and coupling beam. - Two variants of Nonlinear model, designing the core wall (shear walls) according to each variant, studying the influence of damping model on the nonlinear dynamic response, as well as the influence of the coupling beam model on the nonlinear dynamic response. - Design verification, starting with defining the performance objects, and model for time history analysis. Two performance objectives have been studied: Fully operational and Life safety level verifications. - Additional study was performed for the response of non-structural elements due to seismic loading in two cases: Fully operational and Life safety level verifications. - Reinforcement Drawings have been finalized and attached to the report. - Conclusion and recommendations was at the end of the report. It is important for the society, because the used method could be used for the seismic design of any building. It could be wood building or masonry building. Designing a masonry building case will be the subject of future research project. Overall objectives: Linear and Nonlinear seismic design of reinforced concrete building using the performance bases seismic design.:Acknowledgement 4 PART I: General Information, Site and Loading 5 1. General Information About the Building 5 1.1. Specified Material Properties: 6 1.2. Site Information: 6 1.3. Geometry (Figure I.1): 7 2. Site Seismicity and Design Coefficients 7 2.1. USGS Results 7 2.2. Site Response Spectra 8 2.3. Design Coefficients And Factors For Seismic Force-Resisting Systems 8 3. Loading 9 3.1. Determination Of Seismic Forces 9 3.2. Modal Response Spectrum Analysis 9 3.3. Seismic Load Effects And Combinations 11 PART II: Core Wall Design - Linear Model 12 4. Model of ETABS 12 4.1. Geometry 12 4.2. Gravity Loads 13 4.3. Seismic Loads 15 4.4. Tabulated Selected Results From ETABS Analysis 16 5. P-M Interaction Diagrams 17 5.1. N-S Direction 17 5.2. E-W Direction 19 6. Lateral Force Resisting System, Linear 20 6.1. Longitudinal Reinforcement 20 6.2. Shear Reinforcement 22 6.3. Boundary Elements 24 6.3.1. Transverse Reinforcement Of Boundary Elements 26 6.4. Coupling Beams 27 7. Detailing 30 PART III: Site Response Spectra and Input Ground Motions 31 8. Performance Levels 31 8.1. ASCE 7-16 Target Spectra 31 8.2. Site Response Spectra 34 8.2.1. Ground Motion Conditioning 34 8.2.2. Amplitude Scaling 37 8.2.3. Pseudo Acceleration and Displacement Response Spectra 38 PART IV: Non-Linear Model 40 9. Variant 1 of Non-Linear Model 40 9.1. Complete Core Wall Design for Combined Axial-Flexure 40 9.2. Modal Analysis 43 9.3. Influence of the Damping Model on the Nonlinear Dynamic Response 49 10. Variant 2 of Non-Linear Model 57 10.1. Influence of the Coupling Beam Model on the Nonlinear Dynamic Response 57 10.2. Estimated Roof Displacement 68 PART V: Design Verification 70 11. General 70 11.1. Performance Objectives 70 11.2. Model For Time-History Analyses 71 11.3. Performance Level Verification 71 11.4. Fully Operational Performance Level Verification 71 11.5. Life Safety Performance Level Verification 78 PART VI: Capacity Design of Force Controlled Elements and Regions and Design of Acceleration-Sensitive Nonstructural Elements 87 12. General 87 12.1. Design Verification 87 12.1.1. Full Occupancy Case 87 12.1.2. Life Safety Case 91 12.1.3. Observations on Plots 93 12.2. Acceleration response spectra at roof level 94 12.2.1. Observations on Plots 95 12.3. Core Wall 97 12.4. Design Detail Comparison 103 12.5. Detailed Drawing 103 12.6. Diaphragm 104 12.7. Fire Sprinkler System 117 12.8. Overhanging Projector 119 PART VII: Conclusion 122

Liquefaction is a major challenge in geotechnical engineering in which soil strength and stiffness are compromised due to earthquake activity. Understanding and predicting the behaviour and liquefaction susceptibility of soils under cyclic loading is a critical issue in civil engineering, mining and protective engineering. Numerous earthquake-induced ground failure events (e.g., substantial ground deformation, reduced bearing capacity) or liquefaction in natural fine-grained soils or manmade fine-grained soils (i.e., fine tailings) produced by mining activities have been observed and reported in the literature. Tailings are manmade soils that remain following the extraction of metals and minerals from mined ore in a mine processing plant. Traditionally, such tailings are stored in surface tailings impoundments at the mine’s surface. However, geotechnical and environmental risks and consequences related to conventional tailings impoundments have attracted the attention of the engineering community to develop novel methods of tailings disposal and management to minimize geotechnical and environmental risks. Thus, engineers have introduced and implemented innovative tailings technologies—thickened tailings and paste tailings—as cost-effective means for tailings management in mining operations. As both thickened tailings and paste tailings have lower water content and higher solid content than tailings in conventional impoundments, these tailings may be more resistant to liquefaction. However, it should be noted that the seismic or cyclic behaviour of these thickened and paste tailings, with and without heavy rainfall effects, are not fully understood. There is little technical information or data about the behaviour and liquefaction of thickened and paste tailings under seismic or cyclic loading conditions. The objective of the present PhD research is to investigate the response of layered thickened and paste tailings deposits, with and without heavy rainfall effects, to cyclic loads by conducting shaking table tests. To simulate the field deposition of thickened and paste tailings, tailings were deposited in three thin layers in a flexible laminar shear box (FLSB) attached to the shaking table equipment. A sinusoidal seismic loading at a frequency of 1 Hz and peak horizontal acceleration of 0.13g was applied at the bottom of the layered tailings deposits. Acceleration, displacement and pore water pressure responses to the cyclic loading were monitored at the middle depth of each layer of the tailings deposits. Regarding the acceleration response of these thickened and paste tailings deposits (without the effect of heavy rainfall), there was no difference between the middle of the bottom and middle layers or at the base of the shaking table. However, the acceleration at the middle of the top layer differed from the acceleration at the base of the shaking table. Throughout shaking, the layered tailings deposits (with and without the effect of heavy rainfall) exhibited contraction and dilation responses. The excess pore water pressure ratios of the layered thickened tailings deposit that was not exposed to heavy rainfall prior to shaking were found to exceed 1.0 during shaking. However, for the layered paste tailings deposit that was not exposed to the effect of heavy rainfall prior to shaking, the excess pore water pressure ratios were found to be lower than 0.85 during shaking. This reveals that without the effect of heavy rainfall, the layered thickened tailings deposit was susceptible to liquefaction, whereas the layered paste tailings deposit was resistant to liquefaction during shaking. The excess pore water ratios of the layered thickened and the paste tailings deposits that were exposed to heavy rainfall prior to shaking were found to be lower than 0.8 during shaking. This reveals that with the effect of heavy rainfall, the layered thickened and paste tailings deposits were resistant to liquefaction during shaking. The results and findings of this PhD research thus provide valuable information for the implementation of tailings in earthquake-prone areas.

The Mississippi River Valley, is hardly known as an earthquake zone, but may in fact be a natural disaster just waiting to happen. Historical records and paleoseismic investigations have shown that large magnitude earthquakes have occurred in the area and there are constantly microquakes all along the New Madrid Fault System. The inhabitants of the Midwest are living in a death trap so long society doesn’t preoperly prepare for earthquakes. The study presented here aims to prove that, as predicting earthquakes is difficult to the point of impossible, the only serious alternative is to reinforce existing buildings and infrastructure and make sure all new developments are seismically safe. The conclusion reached is, that although expensive, building earthquake safe and retrofitting existing buildings, is for the high risk areas by far cheaper than doing nothing when, not if, a new large magnitude earthquake occurs. For a city in the high risk area, the cost of retrofitting the current structures was 13 billion dollar to be compared with the 100 billion dollars in lost lives and properties of a worst case scenario.

The research attempts to resolve which method of estimation is the most consistent for the parameters of the earthquake model, and how these different methods of estimation, as well as other changes, in the earthquake model parameters affect the damage estimates for a specific area. The research also investigates different methods of parameter estimation in the context of the log-linear relationship characterised by the Gutenberg-Richter relation. Traditional methods are compared to those methods that take uncertainty in the underlying data into account. Alternative methods based on Bayesian statistics are investigated briefly. The efficiency of the feasible methods is investigated by comparing the results for a large number of synthetic earthquake catalogues for which the parameters are known and errors have been incorporated into each observation. In the second part of the study, the effects of changes in key parameters of the earthquake model on damage estimates are investigated. This includes an investigation of the different methods of estimation and their effect on the damage estimates. It is found that parameter estimates are affected by observation errors. If errors are not included in the method of estimation, the estimate is subject to bias. The nature of the errors determines the level of bias. It is concluded that uncertainty in the data used in earthquake parameter estimates is largely a function of the quality of the data that is available. The inaccuracy of parameter estimates depends on the nature of the errors that are present in the data. In turn, the nature of the errors in an earthquake catalogue depends on the method of compilation of the catalogue and can vary from being negligible, for single source catalogues for an area with a sophisticated seismograph network, to fairly impactful, for historical earthquake catalogues that predate seismograph networks. Probabilistic seismic risk assessment is used as a catastrophe modelling tool to circumvent the problem of scarce loss data in areas of low seismicity and is applied in this study for the greater Cape Town region in South Africa. The results of the risk assessment demonstrate that seemingly small changes in underlying earthquake parameters as a result of the incorporation of errors can lead to significant changes in loss estimates for buildings in an area of low seismicity. / Dissertation (MSc)--University of Pretoria, 2014. / Insurance and Actuarial Science / MSc / Unrestricted

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23176号 / 工博第4820号 / 新制||工||1753(附属図書館) / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 林 為人, 教授 福山 英一, 准教授 村田 澄彦 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

This paper examines how green areas may be used as strategic recovery zones in the event of an earthquake and how these zones may strengthen the resilience for future quakes in Istanbul. The paper also refers to investigating why the planning system in Turkey can pose a threat for the provision of green areas. Green areas have proven to be an important feature in natural disaster stricken cities for coping with disasters by strengthening the city’s resilience. However due to rapid population growth and high demand for housing and infrastructure, green areas risk disappearing when the city expands. This problem is evident all major cities of turkey and particularly in the country’s largest city Istanbul, where green areas are benign exploited instead of preserved; leaving larger city’s such as Istanbul vulnerable for future earthquake disasters. The high demand for new housing and functioning infrastructure in conjunction with a complicated planning system in Turkey leads to a vaguely regulated planning system, which creates a threat to green areas. This creates an uncertain situation for the city's ability and resilience to withstand a future earthquake disaster. The study will be based on a qualitative method. The empirical material will be presented through a previous research overview and a case study, which is also based on previous research on the subject. Essay analysis will be performed based on a quantitative text analysis based on concepts; urban disaster resilience, green infrastructure, land use planning and governance, presented in the essays theoretical framework. The general conclusions of the study are that there is a lack of good governance in the planning system in Turkey, which creates restrictions for a sustainable and resilient urban planning in the city of Istanbul. Green areas are resilience and capacity building areas in the city to handle future earthquake disaster, by providing open recovery zones in a densely built city. It is therefore important to plan for a long-term land use and to regard the green areas in the city to uphold strong urban disaster resilience for future earthquakes in Istanbul.

La surveillance de la réponse structurale est fondamentale pour estimer la performance des bâtiments et réduire les pertes lors de futurs séismes. Un moyen pratique de détecter les changements de comportement structural consiste à analyser les variations des propriétés élastiques lors d'excitations dynamiques. Dans ce travail, on montre que les variations de la fréquence fondamentale des bâtiments lors de tremblements de terre (faibles à forts) pourraient être expliquées par des processus élastiques non linéaires qui se produisent à l'intérieur du matériau, et qui finalement affectent le comportement macroscopique global des bâtiments. Ces processus élastiques non linéaires sont responsables de la diminution temporaire ou permanente de la rigidité structurale, pouvant expliquer les processus de récupération des propriétés élastiques observés à la suite d'événements sismiques. Cette étude comble le fossé entre des expériences de laboratoire à l'échelle microscopique et des observations sismologiques à l'échelle macroscopique, où l’élasticité non linéaire est également observée. Dans un premier temps, une base de données sismiques établie dans le cadre de cette thèse est présentée, incluant des réponses de bâtiments instrumentés de façon permanente dans le monde: des milliers d’enregistrements de mouvements sismiques et plusieurs bâtiments du Japon et des États-Unis ont été traités, apportant des connaissances utiles pour le domaine du génie parasismique, notamment pour la prédiction empirique de la réponse structurale en fonction de mesures d'intensité du mouvement au sol. Les incertitudes associées à la prédiction d’endommagement sont présentées, ainsi que l'évaluation de la vulnérabilité d'un bâtiment sous forme de courbes de fragilité. Ensuite, la base de données est utilisée pour analyser les signatures élastiques non linéaires dans les bâtiments, en particulier les effets de la dynamique lente (ou relaxation). Les variations des fréquences de résonance sont étudiées à court et à long terme, en estimant la contribution du sol à la réponse du système sol-structure. Différents états structuraux sont déduits en fonction des amplitudes de chargement et propriétés observées via les enregistrements. Des modèles de relaxation développés en laboratoire sont ensuite adaptés aux données des bâtiments afin de caractériser la densité de fissuration et les hétérogénéités, en effectuant des comparaisons entre les états structuraux avant et après de fortes excitations telles que le séisme de 2011 (Mw=9) de Tohoku (Japon). Les effets des chargements sont observés lors de la récupération des séquences de répliques. Les résultats sont étendus à différentes typologies de bâtiments, en analysant l'influence du matériau et des caractéristiques de chargement, notamment les taux de déformation. Enfin, quelques conclusions générales sont présentées, ainsi qu'une perspective de travail utilisant des outils de machine learning pour prédire la réponse de bâtiments en fonction de signatures élastiques non linéaires observées. / Monitoring structural response is fundamental for evaluating the performance of buildings and reducing losses during future earthquakes. One practical way to detect changes in structural behavior is analyzing variations of elastic properties during dynamic excitations. Here we show that variations in the fundamental frequency of buildings during (weak -to- strong) earthquakes might be explained by nonlinear elastic processes carried out within the structural material, which affect the global macroscopic structural behavior. These nonlinear elastic processes are responsible for both transitory and permanent structural softening, and might explain the intriguing recovery effects observed in the fundamental frequency of buildings following seismic events. This study bridges the gap between microscale laboratory experiments and macroscale seismological observations, where nonlinear elasticity is also observed. In the first part of this study, a new seismic database of building responses is presented: thousands strong motion recordings and several buildings from Japan and US were processed, providing useful tools for the earthquake engineering community, notably for the empirical prediction of structural response as a function of several ground motion intensity measures. Examples of uncertainties associated to damage prediction are presented, as well as the vulnerability assessment of a building throughout fragility curves. Next, the seismic database is used to analyze nonlinear elastic signatures in buildings, particularly the slow dynamics or relaxation effects. Variations of resonant frequencies are monitored at both short and long-term, estimating the contribution of soil in the response of the system soil-structure. Different levels of damage are inferred according to loading amplitudes and structural states. Some laboratory-based models of relaxation are adapted to the building data in order to infer crack-density and heterogeneities over time, making comparisons between structural states before and after large excitations such as the Mw 9 Tohoku earthquake. Conditioning effects are observed during the backbone recovery of aftershocks sequences. The results are extended to different building typologies, analyzing the influence of structural material and loading features, notably strain-rates. Finally, some general conclusions are presented, together with a perspective work using machine learning to predict building response based on nonlinear elastic signatures.