Communities on Vancouver Island, British Columbia face significant exposure to damaging earthquakes. This seismic risk arises not only from the Island’s proximity to crustal, sub-crustal and subduction earthquake sources in the Cascadia Subduction Zone and from their associated aftershock sequences, but also from environmental (natural and human-made) and social vulnerabilities in Vancouver Island communities and their current capacities to respond and recover from a large seismic event. Seeking to 1) assist community officials and the general public to better understand the scope of the earthquake risk on Vancouver Island; 2) raise awareness of the gaps in Vancouver Island’s risk assessment; 3) encourage and facilitate comprehensive seismic risk discussions at all levels of governance; and 4) offer quantitative data on which to base sound funding and policy decisions, this dissertation offers three new studies, presented in paper format, toward the comprehensive management of seismic risk on Vancouver Island. The first paper, reviews the components of risk and, building on international risk management standards and best practices, develops a new, comprehensive Disaster Risk Management (DRM) Framework for practitioners. This DRM Framework is then used to review existing knowledge of Vancouver Island’s seismic risk. A number of information gaps are identified, and two in particular, mainshock and aftershock hazard assessment, are targeted for further analysis. / Graduate

This research employs a deterministic seismic risk assessment methodology to assess the potential damage and loss at meshblock level in the Christchurch CBD and Mount Pleasant primarily due to building damage caused by earthquake ground shaking. Expected losses in terms of dollar value and casualties are calculated for two earthquake scenarios. Findings are based on: (1) data describing the earthquake ground shaking and microzonation effects; (2) an inventory of buildings by value, floor area, replacement value, occupancy and age; (3) damage ratios defining the performance of buildings as a function of earthquake intensity; (4) daytime and night-time population distribution data and (5) casualty functions defining casualty risk as a function of building damage. A GIS serves as a platform for collecting, storing and analyzing the original and the derived data. It also allows for easy display of input and output data, providing a critical functionality for communication of outcomes. The results of this study suggest that economic losses due to building damage in the Christchurch CBD and Mount Pleasant will possibly be in the order of $5.6 and $35.3 million in a magnitude 8.0 Alpine fault earthquake and a magnitude 7.0 Ashley fault earthquake respectively. Damage to non-residential buildings constitutes the vast majority of the economic loss. Casualty numbers are expected to be between 0 and 10.

Cemented paste backfill (CPB) is a novel technology developed in the past few decades to better manage mining wastes (such as tailings) in environmentally friendly way. It has received prominent interest in the mining industry around the world. In this technology, up to 60% of the total amount of tailings is reused and converted into cemented construction material that can be used for secondary support in underground mine openings (stopes) and to maximize the recovery of ore from pillars. CPB is an engineered mixture of tailings, water, and hydraulic binder (such as cement), that is mixed in the paste plant and delivered into the mine stopes either by gravity or pumping. During and after placing it into the mine stopes, the performance of CPB mainly depends on the role of the hydraulic binder, which increases the mechanical strength of the mixture through the process of cement hydration. Similar to other fine-grained soils undergoing cementations, CPB’s behavior is affected by several conditions or factors, such as cement hydration progress (curing time), chemistry of pore water, mixing and curing temperature, and filling strategy. Also, it has been found that fresh CPB placed in the mine stopes can be susceptible to many geotechnical issues, such as liquefaction under ground shaking conditions. Liquefaction-induced failure of CPB structure may cause injuries and fatalities, as well as significant environmental and economic damages. Many researches studied the effect of the aforementioned conditions on the static mechanical behavior of CPB. Other researches have evaluated the liquefaction behavior of natural soils and tailings (without cement) during cyclic loadings using shaking table test technique. Only few studies investigated the CPB liquefaction during dynamic loading events using the triaxial tests. Yet, there are currently no studies that addressed the liquefaction behavior of CPB under the previous conditions by using the shaking table technique. In this Ph.D. study, a series of shaking table tests were conducted on fresh CPB samples (75 cm × 75 cm ×70 cm), which were mixed and poured into a flexible laminar shear box (that was designed and build for the purpose of this research). Some of these shaking table tests were performed at different maturity ages of 2.5 hrs, 4.0 hrs, and 10.0 hrs, to investigate the effect of cement hydration progress on the liquefaction potential of CPB. Another set of tests were conducted to assess the effect of the chemistry (sulphate content) of the pore-water on the cyclic response of fresh CPB by exposing cyclic loads on couple of CPB models that contain different concertation of sulphate ions of 0.0 ppm and 5000 ppm. Moreover, as part of this study, series of shaking table test was conducted on CPB samples that were prepared and cured at different temperatures of 20oC and 35oC, to evaluate the effect of temperature of the cyclic behavior of CPB. Furthermore, the effect of filling strategy on the cyclic behavior of fresh CPB was assessed by conducting set of shaking tables tests on CPB models that were prepared at different filling strategies of continuous filling, and sequential or discontinuous (layered) filling. The results obtained show that CPB has different cyclic behavior and performance under these different conditions. It is observed that the progress of cement hydration (longer curing time) enhances the liquefaction resistance of CPB, while the presence of sulphate ions diminishes it. It is also found that CPB mixed and cured in low temperature is more prone to liquefaction than those prepared at higher temperatures. Moreover, the obtained results show that adopting the discontinuous (layered) filling strategy will improve the liquefaction resistance of CPB. The finding presented in this thesis will contribute to efficient, cost effective and safer design of CPB structures in the mine areas, and will help in minimizing the risks of liquefaction-induced failure of CPB structures.

Buildings with torsional irregularity represent the main focus of many current investigations. However, despite this volume of research, there is no established framework that describes adequately the seismic vulnerability of reinforced concrete shear wall systems. In this study, the three-dimensional behavior of a particular shear-wall structure under earthquake effects was examined with regard to the nonlinear behavior of the reinforced concrete assembly and the parameters that characterize the structure exposed to seismic motion for damage assessment. A three story reinforced concrete shear-wall building was analyzed using the finite element method based ANSYS software. The scaled model building was subjected to shaking table tests at Saclay, France. The project was led by the Atomic Energy Agency (CEA Saclay, France) under the &ldquo / SMART 2008 Project.&rdquo / The investigation was conducted in two phases. In the first phase, the results of the finite element method and experiments were examined, and were reported in this study. For time history analysis, micro-modeling was preferred due to allowing inclusion the nonlinear effects of concrete and steel for analysis. The guiding parameters (acceleration, displacement, strain) of analytical results are compared with the corresponding values that were measured in the experiments to be able to quantify the validity of models and simulation. For the comparison of v the numerical model results with the experimental results FDE (Frequency Domain Error) method was used. After comparison of the numerical model results with the experimental results, the second phase of the SMART 2008 Project was undertaken. The second phase consisted of two parts summarized as &ldquo / Sensitivity Study&rdquo / and &ldquo / Vulnerability Analyses&rdquo / . However, in this report only the sensitivity study and fragility analyses will be reported. Sensitivity study was done to understand which parameters affect the response of the structure. Twelve parametric cases were investigated under two different ground motions. Different behavior parameters were investigated. The effective damping coefficient was found to affect the structural response at 0.2 g design level as well as at 0.6 g over-design level. At the design level, it was observed that elasticity modulus of concrete and additional masses on the specimen determined as effective on the calculated results. To derive the failure probabilities of this structure under various earthquake forces for the given limit states, fragility curves were obtained. Different seismic indicators such as PGA (Peak ground acceleration), PGV (Peak ground velocity), PGD (Peak ground displacement) and CAV (Cumulative absolute velocity) were used as seismic indicators and MISD (Maximum interstory drift) were used as damage indicator for fragility curves. In all 30 time history analyses were done. Regression analyses using least squares method were performed to determine the median capacity and its deviation. Correlation coefficients of the time history data versus fitted curves obtained from the regression analyses changes between 0.65 and 0.99. The lower cases were for PGD- MISD graphs. The scatter of the fragility curves calculated for each damage limit was slightly wider. HAZUS MH MR1 (2003) damage states were also used for the calculation of the fragility curves and compared with the SMART 2008 damage states.

Simulating the non-linear response of reinforced concrete (RC) buildings subjected to a sequence of input earthquake records, is an extremely complex concern in the field of the Earthquake Engineering. Buildings with no symmetry in plan have much more complicated behavior under earthquake effects than symmetric buildings. Torsional irregularity in plan is the main topic of many current researches. In previous decades, considerable amount of numerical and experimental studies have been conducted, but more researches are needed in order to confirm a better understanding of the concept of seismic behavior of these structures. In this study modeling and analyses efforts to simulate the experimental response of a scaled three dimensional reinforced concrete shear wall structure tested on a shaking table, are presented. The model structure is a &frac14 / scale of a three story reinforced concrete building that has torsion due to plan irregularity and layout of structural walls. In order to simulate response quantities measured for the specimen tested on a shaking table, a series of non-linear time history analyses were performed. This structure subjected to AZALEE shaking table tests in Saclay, France under the project of &ldquo / SMART 2008&rdquo / which was led by CEA (Atomic energy agency). The model building was tested under a set of bi-directional synthetic and real ground motions that have varying intensities, peak ground accelerations ranging from 0.1g to 1g. Ground motions were applied sequentially to the specimen, starting with the one having the smallest intensity. Displacements and accelerations measured at different locations on the plan at third story were compared with the numerically computed values in order to check the validity of the Finite Element Model that has been obtained in ANSYS ver.12.1.

Liquefiable soils are common at ports due to the use of hydraulic fills for construction of waterfront facilities. Liquefaction-induced ground failure can result in permanent ground deformations that can cause loss of foundation support and structural damage. This can lead to substantial repair and/or replacement costs and business interruption losses that can have an adverse effect on the port and the surrounding community. Although numerous soil improvement methods exist for remediating a liquefaction-prone site, many of these methods are poorly suited for developed sites because they could damage existing infrastructure and disrupt port operations. An alternative is to use a passive remediation technique. Treating liquefiable soils with colloidal silica gel via permeation grouting has been shown to resist cyclic deformations and is a candidate to be used as a soil stabilizer in passive mitigation. The small-strain dynamic properties are essential to determine the response to seismic loading. The small-to-intermediate strain shear modulus and damping ratio of loose sand treated with colloidal silica gel was investigated and the influence of colloidal silica concentration was determined. The effect of introducing colloidal silica gel into the pore space in the initial phase of treatment results in a 10% to 12% increase in the small-strain shear modulus, depending on colloidal silica concentration. The modulus reduction curve indicates that treatment does not affect the linear threshold shear strain, however the treated samples reduce at a greater rate than the untreated samples in the intermediate-strain range above 0.01% cyclic shear strain. It was observed that the treated sand has slightly higher damping ratio in the small-strain range; however, at cyclic shear strains around 0.003% the trend reverses and the untreated sand begins to have higher damping ratio. Due to the nature of the colloidal silica gelation process, chemical bonds continue to form with time, thus the effect of aging on the dynamic properties is important. A parametric study was performed to investigate the influence of gel time on the increase in small-strain shear modulus. The effect of aging increases the small-strain shear modulus after gelling by 200 to 300% for the 40-minute-gel time samples with a distance from gelation (time after gelation normalized by gel time) of 1000 to 2000; 700% for the 2-hour-gel time sample with a distance from gelation of 1000; and 200 to 400% for the 20-hour-gel time samples with a distance from gelation of 40 to 100. The treatment of all potentially liquefiable soil at port facilities with colloidal silica would be cost prohibitive. Identifying treatment zones that would reduce the lateral pressure and resulting pile bending moments and displacements caused by liquefaction-induced lateral spreading to prevent foundation damage is an economic alternative. Colloidal silica gel treatment zones of varying size and location were evaluated by subjecting a 3-by-3 pile group in gently sloping liquefiable ground to 1-g shaking table tests. The results are compared to an untreated sample. The use of a colloidal silica treatment zone upslope of the pile group results in reduced maximum bending moments and pile displacements in the downslope row of piles when compared to an untreated sample; the presence of the treatment zone had minimal effect on the other rows of piles within the group.

The presented research investigated the viability of a double-braided synthetic fiber rope for providing improved performance of steel moment frames subjected to earthquake-induced ground motions. A series of experimental tests, including a 1:3-scale dynamic test and 1:6-scale shaking table tests, was conducted using Northridge ground-motion input. A series of nonlinear dynamic analytical studies, using DRAIN-2DX, was conducted to develop the experimental tests. Throughout experimental testing, the ropes exhibited a hyper-elastic loading response and a reduced-stiffness unloading response. A conditioning cycle was defined as a loading cycle induced in the rope above the highest load expected to be experienced by the rope, and was determined to be requisite for ropes intended to be used for the stated objectives of the research program. After experiencing a conditioning cycle, the rope response returned to initial conditions without permanent deformation, demonstrating repeatability of response through several loading cycles below the conditioning load. In the 1:6-scale shaking-table experiments, the ropes drastically improved the performance of the steel moment frames. Maximum and residual drift were reduced significantly, with a corresponding minimal increase to the maximum base shear. Base shear was reduced at several peaks subsequent to the initial pulse of the Northridge ground-motion input. The analytical model developed was excellent for predicting elastic response of the 1:6-scale shaking table experiments and adequate for the purpose of planning shaking table studies. Correlation of peak rope forces between the analytical model and experimental results was poor, and was attributed to limitations of the pre-defined elements used to represent the rope devices in the software program. The inability of the elements to capture the complex unloading response of the rope was specifically noted. / Ph. D.

Seismic safety of underground structures (culvert, subway, natural gas and water sewage systems) plays a major role in sustainable public safety and urban development. Very few experimental data are currently available and there is not generally accepted procedure to estimate the dynamic pressures acting on underground structures. This study aims to enhance the state of prevalent information necessary in understanding the dynamic behavior of box culverts and the stresses acting under dynamic excitations through experimental analyses. For this purpose, a series of shaking table tests were conducted on box-type culverts buried in dry sand. To simulate the free-field boundary conditions, a laminar box was designed and manufactured for use in a 1-g shake table. Four culvert models having different rigidities were tested under various harmonic motions in order to examine the effect of flexibility ratio on dynamic lateral soil pressures. Based on the tests results, a simplified dynamic pressure distribution acting on sidewalls of the culvert model was suggested. Then, a dynamic lateral coefficient was defined for the proposed peak pressure value in the distribution. The values of this coefficient were obtained as a function of shear strain and relative stiffness between the soil and underground structure. Finally, a simplified frame analysis approach was suggested for the assessment of the forces on the structure, to help to carry out a preliminary design of box-type culverts. In this approach, it was assumed that the culvert was fixed at bottom and subjected to lateral stresses on sidewalls and shear stresses on the upper face. For the confirmation of the method, centrifuge tests were conducted on a box-type culvert model under the Seventh Framework Programme of European Union with Grant Agreement No.227887. Results show that the proposed simplified procedure can be used in reasonable accuracy as a practical approach for the preliminary assessment of box-type culverts buried in dry sand under seismic action.

Static and dynamic interaction mechanism of the retained soil-compressible geofoam buffer and yielding retaining structures requires further investigation. The present study, initiated on this motive, discusses the results of 1-g physical model tests and numerical analyses of cantilever retaining walls with and without deformable geofoam buffers between the wall and cohesionless granular backfill. 0.7m high walls with various wall thicknesses were utilized in the physical modeling. Dynamic tests were carried out by using a laminar container placed on a uni-axial shaking table. Influence of buffer thickness, geofoam type and wall flexibility as well as base excitation characteristics on the lateral earth pressures and flexural wall deflections were under concern. Outcomes of the analyses performed with FLAC-2D (v6.0) finite difference code were validated against the results of the physical model tests. It was observed that the arching effect induced in the retained soil by the lateral compression of the lower half of the geofoam buffer has a positive effect, as this zone is able to absorb a portion of the total unbalanced lateral force exerted by the backfill thus causing a reduction in the static and seismic lateral wall pressures. Relative thickness and stiffness of the geofoam buffer appear to be the most dominant factors affecting the reduction in earth thrust. Lateral earth pressure coefficients determined from physical model tests were compared with those calculated using methods available in the literature. Good agreement was observed between the predictions. Graphs were provided to estimate the static and dynamic lateral earth pressure coefficients for various combinations of wall stiffness and buffer characteristics. Analysis of a 6m high prototype cantilever wall subjected to an excitation recorded in August 17, 1999 Kocaeli earthquake by finite difference method exhibited the contribution of geofoam buffers on seismic performance of cantilever earth retaining walls. It was observed that the presence of an EPS geofoam inclusion provides a reduction of the permanent flexural wall deflections as well as total seismic thrust likely to be experienced by the wall during an earthquake.

Στη παρούσα εργασία, δημιουργήθηκε ένα εκπαιδευτικό περιβάλλον εικονικής πραγματικότητας για προσομοίωση σεισμού σε σχολική τάξη. Πρόκειται για ένα ασφαλές περιβάλλον, εφικτού κόστους, που προσομοιώνει αρκετά καλά το φυσικό. Παρουσιάζεται ο τρόπος κατασκευής των αντικειμένων της τάξης με τη χρήση λογισμικού μοντελοποίησης και η δημιουργία διαφόρων συμβάντων που λαμβάνουν χώρα κατά τη διάρκεια του σεισμού, με τη χρήση λογισμικού εικονικής πραγματικότητας. Η εφαρμογή δίνει τη δυνατότητα στο μαθητή να αποκτήσει ψυχολογική εξοικείωση και να ενισχύσει την αντιληπτικότητά του σχετικά με το φαινόμενο, να βελτιώσει την απόδοσή του αποκομίζοντας καινούργιες εμπειρίες και ταυτόχρονα να εφαρμόζει όσα έχει μάθει για τους τρόπους αντίδρασης σε περίπτωση σεισμού σε συνθήκες πραγματικού γεγονότος. / An educational environment of virtual reality was designed in order to simulate an earthquake occurring while students are present in a classroom. Such a virtual environment has many advantages: it is secure for students, not costly and very similar to the real life one that is to the actual classroom in the sense that students are free to interact within its confines. The present dissertation attempts to present the ways through which school elements can be produced using a modelling tool. Additionally, we have created a variety of incidents taking place while the earthquake is occurring using a virtual reality software. Summing up, this application offers students the opportunity to psychologically familiarize themselves with the phenomenon of an earthquake while at the same time reinforces their awareness of it. It offers students the possibility to acquire new experiences and improve their performance in crisis management (e.g. earthquake), and it simultaneously sets while an example-environment to apply their theoretical knowledge in real life situations.