The linear elastodynamic two-dimensional anti-plane stress problem, where deformations occur in only one direction is considered for one sided non-planar faults. Fault dynamics are modeled using purely velocity dependent friction laws, and applied on boundaries with complex geometry. Summation-by-parts operators and energy estimates are used to couple a high-order finite difference method with an unstructured finite volume method. The unstructured finite volume method is used near the fault and the high-order finite difference method further away from the fault where no complex geometry is present. Boundary conditions are imposed weakly on characteristic form using the simultaneous approximation term technique, allowing explicit time integration to be used. Numerical computations are performed to verify the accuracy and time stability, of the method.

This study is designed to investigate the relationships among affective and cognitive personal qualities leading to psychological resilience among natural disaster survivors. The main assumption of this study is that positive personal qualities might be associated with better psychological adjustment. The study aimed at testing a hypothesized theoretical model accounting for resilience with regard to personal qualities. The sample for this study was composed of individuals who were exposed to earthquakes that occurred in 1999 in Marmara region of Western Turkey. The study hypothesized that the dispositional cognitive and affective constructs (hope, optimism, life satisfaction, self esteem and positive affect) play vital roles in pathways to psychological resilience. Initially hypothesized model based on cognitive-behavioral theoretical foundations was proposed and tested. The cognitive behavior approach holds the idea that thoughts are the determinants of functional and dysfunctional emotions and behaviors. In the model, global self esteem serve as an underlying mechanism that helps to human operate well on the environment. The positive influence of global self esteem can be observed in cognitive process and affective domain in individuals. Simultaneously a person develops an optimistic worldview based on the global self esteem. Self esteem leads a person to construe positive cognitive constructs influencing the general world of view positively and utilize those cognitive. Since thinking patterns influence the affective side of the person, if the person utilizes positive cognitive constructs while interpreting life events, he or she is likely to experience more positive feelings and to be satisfied with life at the same time The hypothesized model was trimmed. Dispositional hope (pathways and agentic thinking), optimism, positive affect, life satisfaction and self-esteem were regarded as independent latent variables while three factors of psychological resilience were valued as the latent dependent variables. Finally, a structural model was suggested to account for the pathways leading to resilience among the Turkish disaster survivors. According to the model, self esteem, dispositional hope and optimism have indirect effect on resilience components via positive affect and life satisfaction. For purposes, the Ego Resilience Scale was adapted into Turkish. Exploratory factor analysis yielded three-factor solution for Turkish disaster survivors and the resilience factors were labeled as Personal Strengths Relating Recovery / Positive Self-Appraisals and Openness to New Experience. The results revealed that the Ego Resiliency Scale is a validated and reliable measure of psychological resilience among Turkish disaster survivors.

Turkey is located on a seismically active region and ranks high among all countries that have suffered losses of life and property due to earthquakes over many centuries. In addition, its building stock has usually poor construction quality with seismically improper structural systems. These lead to a need for rapid and reliable assessment and retrofit procedures. In the 2007 Turkish Earthquake Code, a new chapter is included for assessment and retrofit of existing buildings. The assessment procedures proposed in the Code are classified as linear elastic and nonlinear procedures. An engineer is allowed to choose one of these two procedures without any restriction. In this study, a research was undertaken in order to clarify the differences between the seismic assessment procedures in the 2007 Turkish Earthquake Code. For this purpose, two pairs of existing and retrofitted residential buildings were assessed according to the principles of both procedures proposed in the 2007 Turkish Earthquake Code. The assessment results were also compared with the actual performance observations from a 5-storey building which suffered damage during the 1999 D&uuml / zce earthquake. In addition, an anchorage design methodology was developed for the exterior coupled shear wall retrofit solution, and tested on a 6-storey case study building.

Much emphasis has been given to the damages and loss experienced in the 1999 earthquakes with little research however on the social and administrative causes, and in particular on the consequences of malpractice of planning previous to the natural hazard. Reviewing the case of Adapazari, the three succesive periods of plan making and implementation are critically investigated here to establish the extent that planning decisions of the local authorities and their modes of enforcement have generated adverse results causing the loss of many Lifes. The analysis required the combination of data sources on plan decisions and the consequences of the disaster, accommodated in the different authorities. Surveying the scope and decisions of 1957-70, 1970-85, and 1985-99 plan periods, and comparing these decisions in their spatial context with the loss and damage experienced, provides sufficent evidence of the causality. It is possible to identify that decisions of increased densities and building higher, changes to commercial uses in the CBD, siting of individual buildings, removal of open spaces all had their share in contributing the dramatic panaroma of losses. v Findings indicate strong correlations of loss of life with increased number of floors in buildings in the 27 districts of Adapazari. It is particularly evident that greatest damages occured due to the 1985 plan decisions, when all powers of comprehensive plan-making were transferred to the local authorities, central authority control powers being removed. So long as local interests can not be curbed in plan preparation avoiding control with reference to the criteria of &lsquo / public benefit&rsquo / , many other cities in Turkey are likely to have similar fate in the near future.

To a large extent, natural phenomenon like earthquakes, floods, lanslides and etc may seem &ldquo / natural events&rdquo / which are out of human control. In fact, the sociopolitical structure is the main cause of earth tremors which turn into disasters. What is notable and striking is that, because of institutional and social vulnerabilities and little or misguided efforts for disaster loss mitigation, natural events may turn into disasters resulting negative and devastating consequences. Institutional vulnerabilities connote a lack of local administrations&rsquo / capacity for disaster mitigation planning, furthermore awareness for accreting local stakeholders for disaster loss reduction. Social vulnerabilities, refers to miss-knowledge and lack of awareness for disasters in the society. In Turkey, it is hard to say that there has never been efforts for disaster loss reduction, whereas / the main focus of the state agencies has been on post-disaster emergency relief, literally wound healing for decades. Generally speaking, localities which experience a disaster may encounter significant losses in development, hence a significant decrease in local capacities which takes enormous resources to restore. The housing stock and urban fabric, which inherit an historical background weaved by missguided disaster policy that only focus on post-disaster emergency relief phase, pictures the extent of the problem in Turkey. In addition, both &ldquo / institutional errors which lead to underachievement in disaster policy and practice&rdquo / and &ldquo / opportunities for building robust and resilient forms of institutions&rdquo / come into local agenda. Errors, which might have been altered by long term and comprehensive modes of local planning for disasters, may lead to underachievement by local agents. To achieve such a model, we are in need to carry out qualitative and quantitative data collecting and analyzing techniques in different phases. The two analysis techniques are in-depth interviews (IDI) and drawing Concept Maps that will be conducted in the analyses process with local respondents selected by snowball technique.

In Turkey, most of the existing buildings have been designed according to Turkish Earthquake codes of 1975 and 1997. It is a well known fact that, poor material quality, poor design, poor control on site and inadequate workmanship makes existing buildings vulnerable to earthquake. In addition, change in function of buildings becomes another problem. These problems increase the importance of assessment of existing buildings. For this purpose, a new chapter has been added to the new code and assessment methods of existing buildings is regulated. 2007 Turkish Earthquake Code offered two analysis methods, linear and nonlinear analysis methods. Due to comprehensive computational, modeling and assessment challenges involved in applying the code procedures that are generally not well understood by practicing engineers, the use of commercial package computer programs is preferred. There are widely used three software&rsquo / s in Turkey / Idestatik, Sta4 and Probina. These programs currently handle linear assessment method only. This study aims to compare the assessment results of the most widely used three structural analysis and design softwares in Turkey. For this purpose, four v different structures having different property and plan were employed. These buildings were selected to be representative of the mostly common building types. Each building has been modeled and identified with the same material properties, the same reinforcement details and the same geometric properties in each software. The results of the assessment are compared in order to determine the inconsistencies among the software&rsquo / s and their reliability.

Prior experimental research clearly reveals that the performance of reinforced concrete frame structures under earthquake loading is closely related to the behavior of beam-to-column connection regions. In order for a reinforced concrete building to have an adequate response under high lateral deformations, beam-to-column connections should be able to preserve their integrity. However, even today beam-to-column connections are assumed to be rigid or elastic, leading to an incorrect estimation of the structural response under earthquake loading. One of the basic reasons for the assumption of rigid joints is the lack of analytical models that adequately represent the seismic behavior of the connection region. In this thesis, an analytical model that realistically represents the beam-to-column connection response is developed, in the light of prior experimental data. The experimental subassemblies used in the generation of the analytical model are later modeled in OpenSees environment in order to verify the accuracy of the model. Throughout the research, utmost attention is paid for the model to be simple enough to be used practically and also to cover a wide range of beam to column connection properties.

As Civil Engineering structures, e.g., tall buildings, long span bridges, deep water offshore platforms, nuclear power plants, etc., have become more costly, complex and serve more critical functions, the consequences of their failure are catastrophic. Therefore, the protection of these structures against damage induced by large environmental loads, e.g., earthquakes, strong wind gusts and waves, etc., is without doubt, a worldwide priority. However, structures cannot be designed to withstand all possible external loads and some extraordinary loading episodes do occur, leading to damage or even failure of the structure. Protection of a structure against hazards can be achieved by various means such as modifying structural rigidities, increasing structural damping, and by attaching external devices, known as control devices. Control devices can be deployed either to isolate the structure from external excitation or to absorb input seismic energy to the structure (absorber) so as to mitigate vibration in the primary structure. Seismic base isolation is one such mechanism which isolates a structure from harmful ground excitations. Seismic base isolation is a widely accepted and implemented structural control mechanism due to its robustness and ease in deployment. Following the Northridge earthquake (1994), and Kobe earthquake (1995), the interest of structural engineers in understanding near-source ground motions has enhanced. Documents published after these earthquakes emphasized the issue of large base displacements because of the use of none or little isolation damping (of viscous type only) prior to these events. More recent studies have investigated analytically and experimentally, the efficiency of various dissipative mechanisms to protect seismic isolated structures from recorded near-source long period, pulse-type, high velocity ground motions. Consequently, hybrid isolation systems, seismic base isolation supplemented with damping mechanisms, have become the focus of current research trend in structural vibration control. Hybrid base isolation system incorporating passive supplemental damping devices like, viscous fluid dampers, etc., performs satisfactorily in minimizing isolator displacement but at the same time increases superstructure acceleration response. Furthermore, the passive system can be tuned to a particular frequency range and its performance decreases for frequencies of excitation outside the tunning bandwidth. In such a scenario, active control devices in addition to base isolation mechanism provide better performance in reducing base displacement and superstructure acceleration for a broad range of excitation frequencies. Tremendous power requirement and the possibility of power failure during seismic hazards restrict the usage of active systems as a supplemental device. Semi-active devices provide the robustness of passive devices and adaptive nature of active devices. These characteristics make them better suited for structural control applications. The recent focus is on the development of magnetorheological (MR) dampers as semi-active device for structural vibration control applications. MR dampers provide hysteretic damping and can operate with battery power. The thrust of this thesis is on developing a hybrid base isolation mechanism using MR dampers as a supplemental damping device. The use of MR damper as a semi-active device involves two steps; development of a model to describe the MR damper hysteretic behaviour; development of a proper nonlinear control algorithm to monitor MR damper current / voltage supply. Existing parametric models of MR damper hysteretic behaviour, e.g., Bouc-Wen model, fail to consider the effect of amplitude and frequency of excitation on the device. Recently reported literature has demonstrated the necessity of incorporating amplitude and frequency dependence of MR damper models. The current/voltage supply as the input variable to the MR damper restricts the direct use of any control algorithms developed for active control of structures. The force predicted by the available control algorithms should be mapped to equivalent current/voltage and then to be fed into the damper. Available semi-active algorithms in the literature used ‘on-off’ or ‘bang-bang’ strategy for MR applications due to nonlinear current/voltage-force relation of MR damper. The ‘on-off’ nature of these algorithms neither provides smooth change in MR damper current/voltage input nor considers all possible current/ voltage values within its minimum to maximum range. Secondly, these algorithms fail to consider the effect of the MR damper applied and commanded current/voltage dynamics. The thrust of this dissertation is to develop semi-active control algorithms to monitor MR damper supply current/voltage. The study develops a Bouc-Wen based model to characterize the MR damper hysteretic phenomenon. Experimental results and modeling details have been documented. A fuzzy based intelligent control and two model-based nonlinear control algorithms based on optimal dynamic inversion and integral backstepping have been developed. Performance of the fuzzy logic based intelligent control has been explored using experimental investigation on a three storey base isolated building. Further the application of the proposed controllers on a benchmark building; a benchmark highway bridge and a stay cable vibration reduction have been discussed. Experimental study has revealed that the performance of optimal FLC is better than manually designed FLC in terms of reducing base displacement and storey accelerations. The performance of both the FLCs (simple FLC and genetic algorithm based optimal FLC) is better than ‘passive-off’ (zero ampere current supply) and ‘passive-on’ (one ampere current supply) condition of MR damper applications. The ‘passive-off’ results have shown higher base displacements with lower storey accelerations, whereas, the ‘passive-on’ results have reduced base displacement to the least but at the same time increased the storey acceleration too much. The FLC monitored MR damper show a compromise between the two passive conditions. Analytical results confirm these observations. Numerical simulations of the base isolated building with the two model based MR damper control algorithms developed have shown a better performance over FLC and widely used clipped optimal algorithms. The applications of the proposed semi-active control algorithms (FLC, dynamic inversion and integral backstepping) have shown better performance in comparison to that of control algorithms provided with the benchmark studies.

La variation spatiale du mouvement sismique a des effets significatifs sur la réponse dynamique des structures de génie civil de grandes dimensions. Dans la pratique courante, l'excitation du mouvement sismique le long de la fondation de la structure est considérée uniforme, approche cependant inadéquate pour les structures de large portance au sol localisées à proximité des failles ou sur des sites présentant une structure du sous-sol latéralement hétérogène. Cette thèse se propose donc de comprendre les facteurs clefs contrôlant localement la variabilité spatiale du mouvement sismique, avec en ligne de mire la mise en place de recommendations en vue d'incorporer ces effets dans l'estimation de l'aléa sismique et le dimensionnement des structures. La première partie de cette thèse s'intéresse à la composante intra-évènement de l'écart-type de la distribution du mouvement sismique en champ proche à l'aide de simulations numériques du mouvement sismique pour des sources étendues présentnat une cinématique de rupture réaliste. Les résultats suggèrent que la variabilité intra-évènement dépend significativement du type de rupture, cette variabilité augmentant avec la distance pour les ruptures bilatérales et diminuant pour les ruptures unilatérales. La seconde partie traite de la caractérisation de la composition du champ d'onde dans la vallée de Koutavos-Argostoli, qui est une vallée de petite dimension et d'épaisseur sédimentaire faible, située sur l'île – sismiquement active - de Céphalonie en Grèce. Les champs d'onde générés par 46 séismes, ayant des magnitudes variant entre 2 et 5 et des distances épicentrales jusqu'à 200 km, ont été analysés à partir de l'enregistrement par deux réseaux denses de capteurs sismologiques. L'algorithme de traitement d'antenne MUSIQUE est utilisé pour extraire la vitesse, l'azimut, le type et la polarisation des ondes dominantes se propageant à travers le réseau. Les résultats montrent clairement d'importantes diffractions d'ondes de surface aux bords de vallée au-delà de la fréquence de résonance de la vallée. Tandis que les ondes de Love dominent clairement le champ d'ondes proche de la fréquence de résonance, les ondes de Rayleigh dominent à plus haute fréquence dans des gammes de fréquences étroites. Par ailleurs, un excellent accord est observé entre les champs d'onde de surface diffractés localement et les caractéristiques d'amplification du site. La “cohérence décalée” de la partie la plus énergétique du signal a été quantifiée pour chaque paire de stations du réseau. En général, la cohérence calculée sur les composantes horizontales diminue avec la distance entre stations et la fréquence. La cohérence sur la composante verticale indique des valeurs relativement fortes à haute fréquence. Les valeurs de cohérence apparaissent très faiblement corrélées à la magnitude, l'azimut et la distance épicentrale du séisme, mais sont au contraire liées aux caractéristiques géométriques de la vallée. La coherence est systématiquement plus forte pour les couples de capteurs orientés selon la direction parallèle à l'axe de la vallée, et moins forte pour des couples de capteurs orientés dans la direction perpendiculaires. Cette observation est en accord avec les résultats du traitement d'antenne: la prédominance d'ondes de surface diffractées sur les bords de la vallée conduit à des mouvements en phase le long de la direction parrallèle à l'axe de la vallée. Les résultats de cette thèse apporte des elements de compréhension sur la variabilité spatiale du movement sismique et ouvrent de nombreuses perspectives d'application. / Spatial variation of earthquake ground motion over short distances significantly affects the dynamic response of engineered structures with large dimensions. In current practices, the ground motion excitation across the foundation of a structure is assumed to be spatially uniform, which becomes inadequate for spatially extended structures in the near-fault region or on sites with lateral inhomogeneity. This PhD thesis seeks to understand the key parameters that locally control the ground motion spatial variability with the intent of putting forth practical propositions for incorporating such effects in seismic design and hazard assessment. The first part of the thesis addresses the within-event component of the standard deviation of ground-motion distribution in near source region by means of numerical simulation of ground motions for extended sources with realistic rupture kinematics. The results suggest that the within-event variability significantly depends on the rupture type, depicting an increase with distance for bilateral ruptures and a decrease for unilateral ruptures. The second part deals with the characterization of seismic wave field at the Koutavos-Argostoli site, a small-size, shallow, alluvial valley located in the seismically active Cephalonia Island in Western Greece. The seismic wave field was investigated from the recordings of a dense seismological array for a set of 46 earthquakes, with magnitude 2 to 5 and epicentral distance up to 200 km. The MUSIQUE array analysis algorithm was used to extract the phase velocity, back-azimuth, type and polarization of the dominant waves crossing the array. The results clearly indicate dominant scattering of seismic surface waves, mainly from the valley-edge directions, beyond the fundamental frequency of the valley. While Love surface waves clearly dominate the wave field close to the resonance frequency, Rayleigh waves strongly dominate only in relatively narrow frequency bands at higher frequency. Besides, an excellent consistency is observed between the dominance of the identified surface wave type in the wave field and the site amplification. The "lagged coherency" of the most energetic part of the ground motion has been quantified for each station-pair within the array. In general, spatial coherency estimated from the horizontal components exhibit decays with frequency and interstation distance. Estimates from the vertical component exhibit rather larger values at some higher frequencies. Although coherency does not show any consistent trend indicating dependence on the magnitude, back-azimuth or site-to-source distance of the event, it seems to be primarily controlled by the site geometry. Larger coherency is systematically observed when the station pair is oriented parallel to the valley axis, while lower values are observed in the perpendicular direction. This observation proves to be consistent with the MUSIQUE analysis results: the predominance of scattered surface waves propagating across the valley implies an in-phase motion along valley-parallel direction and out-of-phase motion along valley-perpendicular direction. The findings of the present research are expected to contribute in enhancing our understanding of spatial variability of ground motion and improving the coherency models used in engineering. This work also opens up new insights and many questions in need of further investigation.

Η μεταπτυχιακή διπλωματική εργασία έχει ως στόχο να δημιουργήσει ένα ανοικτού κώδικα λογισμικό (scisola) -σε python-, το οποίο να παρέχει τις ακόλουθες λειτουργίες: Αυτοματοποίηση του υπολογισμού ΤΣΡ με σύνδεση στο σύστημα του SeisComP3. Αποθήκευση των αποτελεσμάτων σε βάση δεδομένων. Δυνατότητα παραμετροποίησης του λογισμικού από το χρήστη με χρήση γραφικού περιβάλλοντος (configuration). Δυνατότητα προβολής των αποτελεσμάτων με χρήση γραφικού περιβάλλοντος (review). Δυνατότητα τροποποίησης των αποτελεσμάτων βάση επιλογής του χρήστη με χρήση γραφικού περιβάλλοντος (revision). / This master thesis contributes by providing an open-source software application (scisola) -written in python-. It supports: Automatic calculation of moment tensors; the seismic event notification, station information and the corresponding waveforms are provided by the SeisComP3 system through different utilities and services like slinktool and seedlink server respectively. The moment tensor is calculated through the ISOLA software in parallel mode using multiple threads through multiprocessing python libraries for much faster calculations. Result storing in database for better data management. Extensive configuration changes based on the needs of each researcher, through a user friendly graphical interface. A graphical overview of the moment tensor calculation and the corresponding data fit. Moment tensor revision in case the user wishes to alter the automatically suggested result.