As an alternative to transverse spiral or hoop steel reinforcement, fiber reinforced polymers (FRPs) were introduced to the construction industry in the 1980's. The concept of concrete-filled FRP tube (CFFT) has raised great interest amongst researchers in the last decade. FRP tube can act as a pour form, protective jacket, and shear and flexural reinforcement for concrete. However, seismic performance of CFFT bridge substructure has not yet been fully investigated. Experimental work in this study included four two-column bent tests, several component tests and coupon tests. Four 1/6-scale bridge pier frames, consisting of a control reinforced concrete frame (RCF), glass FRP-concrete frame (GFF), carbon FRP-concrete frame (CFF), and hybrid glass/carbon FRP-concrete frame (HFF) were tested under reverse cyclic lateral loading with constant axial loads. Specimen GFF did not show any sign of cracking at a drift ratio as high as 15% with considerable loading capacity, whereas Specimen CFF showed that lowest ductility with similar load capacity as in Specimen GFF. FRP-concrete columns and pier cap beams were then cut from the pier frame specimens, and were tested again in three point flexure under monotonic loading with no axial load. The tests indicated that bonding between FRP and concrete and yielding of steel both affect the flexural strength and ductility of the components. The coupon tests were carried out to establish the tensile strength and elastic modulus of each FRP tube and the FRP mold for the pier cap beam in the two principle directions of loading. A nonlinear analytical model was developed to predict the load-deflection responses of the pier frames. The model was validated against test results. Subsequently, a parametric study was conducted with variables such as frame height to span ratio, steel reinforcement ratio, FRP tube thickness, axial force, and compressive strength of concrete. A typical bridge was also simulated under three different ground acceleration records and damping ratios. Based on the analytical damage index, the RCF bridge was most severely damaged, whereas the GFF bridge only suffered minor repairable damages. Damping ratio was shown to have a pronounced effect on FRP-concrete bridges, just the same as in conventional bridges. This research was part of a multi-university project, which is founded by the National Science Foundation (NSF) Network for Earthquake Engineering Simulation Research (NEESR) program.

Many infrastructure networks rely on each other to deliver utilities and services to the community. In the event of a disaster, these networks can sustain significant damage. It is therefore important to identify interdependencies among networks to mitigate the disaster consequences. In 2003, Public Safety Canada (PSC) and NSERC initiated the Joint Infrastructure Interdependencies Research Program (JIIRP) for this purpose. The research was carried out at six Universities across Canada including the University of British Columbia (UBC). The aim of JIIRP at UBC was to study infrastructure interdependencies during disasters in order to aid in decision making. This involved the development disaster simulation methodology and tool, and the implementation of a case study. UBC's Point Grey campus was used as case study. The campus is located in southwestern British Columbia, a known seismic zone, therefore earthquake disaster scenario was chosen. Reasonable estimations of the expected seismic damage and losses are required in order to simulate a realistic disaster scenario. For this reason, in this thesis, seismic risk assessment was carried out for the buildings at UBC. This involved the development of a building database, the assessment of the expected level of damage to the structural and nonstructural building components, and the estimation of monetary, human and functionality losses. Buildings in the database were classified into prototypes and the damage was estimated for several levels ofintensity using damage probability matrices. As expected, the most vulnerable buildings on campus were those containing unreinforced masonry. These buildings make up 7% of the buildings on campus. The least vulnerable buildings were multi-family residential woodbuildings which account for 27% of the buildings on campus. Losses were estimated following the damage assessments. Casualties were estimated for three times of day. 2PM was determined to be the critical time of day as the campus population is the greatest at this time. Monetary loss and functionality trends were examined with respect to earthquake intensity and it was shown that for moderate intensity earthquakes, the losses depend primarily on nonstructural damage, while structural damage plays the most important role for higher intensities. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Plane-wave decomposition and slant stack transformation have recently gained much interest as viable routes to perform a variety of prestack processing tasks, such as velocity estimation, migration, filtering, deconvolution, and velocity inversion. To further complement the current advances, the problem of earth model parameter estimation and prestack structural imaging are addressed in this work. Unlike existing methods, the algorithms presented here make a novel and systematic use of the plane-wave domain to determine migration and interval velocities, interface dip angles and common-shot gather reflector images. To start, a method is developed to estimate migration velocities and interface dip angles in earth models composed of planar, dipping reflecting interfaces separating homogeneous layers, and where straight-ray travelpaths to the reflecting interfaces can be assumed. The method consists of transforming a common-shot gather into the plane-wave domain, where a semblance analysis search along cosinusoid trajectories is performed. Since the cosinusoid trajectories are functions of the migration velocity and interface dip angle, selection of the maximum semblance values yields the best estimates to the desired earth model parameters. To remove the straight-ray assumption of the velocity-dip analysis method, a recursive technique is developed to estimate interval velocities and interface dip angles via a ray tracing algorithm. This technique essentially generates plane-wave domain traveltimes for a range of interval velocities and interface dip angles, and computes the error between the generated and observed plane-wave traveltimes. The minimum error determines the best estimates of the earth model parameters. With the information attained in the velocity-dip analysis algorithm, a plane-wave based imaging method is developed to produce prestack common-shot gather images of the reflecting interfaces. The method consists of transforming a common-shot gather into the plane-wave domain, where a velocity-dip semblance analysis is performed. Then, the plane-wave components are downward extrapolated and recombined via a dip-incorporated inverse slant-stack transformation to produce the spherical-wave field that would have been recorded by receivers placed on the reflecting interfaces. The dip incorporation consists of redefining the angle of emergence of the plane waves. Finally, a simple mapping algorithm converts the offset and time coordinates of the reconstructed wave field to the true horizontal location and two-way vertical time of the reflection points. This results in the desired prestack migrated images of the reflecting interfaces. In this thesis, a novel algorithm to perform plane-wave decomposition via Fourier transforms is also proposed. This algorithm consists of the application of the double fast Fourier transform to the input data, followed by complex vector multiplications with essentially the Fourier representation of the Bessel function J0 . A numerical singularity is avoided by applying an analytical expression that approximately accounts for the singular point contribution. An inverse fast Fourier transform from frequency to time gives the desired plane-wave seismogram. The techniques proposed in this work have yielded encouraging results on synthetic and field data examples. The examples demonstrate, for the first time, the systematic use of the plane-wave domain in processing seismic reflection data from common-shot gather data to the plane-wave domain, to velocity and dip angle analysis and to prestack structural imaging. It is believed that the results from this work will help researchers as well as practising geophysicists to become better acquainted with plane-wave domain processing. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Chebychev semi-discretizations for both ordinary and partial differential equations are explored. The Helmholtz, heat, Schrӧdinger and 15° migration equations are investigated. The Galerkin, pseudospectral and tau projection operators are employed, while the Crank-Nicolson scheme is used for the integration of the time (depth) dependence. The performance of the Chebychev scheme is contrasted with the performance of the finite difference scheme for Dirichlet and Neumann boundary conditions. Comparisons between all finite difference, Fourier and Chebychev migration algorithms are drawn as well. Chebychev expansions suffer from neither the artificial dispersion dispersion of finite difference approximations nor the demand for a periodic boundary structure of Fourier expansions. Thus, it is shown that finite difference schemes require at least one order of magnitude more points in order to match the accuracy level of the Chebychev schemes. In addition, the Chebychev migration algorithm is shown to be free of the wraparound problem, inherent in migration procedures based on Fourier transform. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The integrated processing and interpretation of VSP data are developed to work together in order to enhance the final VSP interpretation. Furthermore, the interpretive processing of the VSP data within the case histories are reviewed along with the incorporation of the final VSP results (both near and far offset data) into the integrated geological/geophysical interpretations presented in the case studies. This thesis has attempted to personify the term "interpreter/processor" as first highlighted in Hardage (1985). The case histories pertain to oil and gas exploration in carbonate reef and sandstones in the Western Canadian Sedimentary Basin (WCSB). The Lanaway case history (Hinds et al., 1994a) pertains to the exploration of the Lanaway/Garrington oil field located in central Alberta, Canada. The surface seismic interpretation over the reef crest differed dramatically from the isopach of the reef-encasing shales derived from the geological logs of a borehole drilled into the reef crest. To understand the discrepancy, a VSP survey was performed and the data were interpretatively processed. The results were integrated with the known geology of the field area to uncover possible reasons for the surface seismic anomaly. field in central Alberta, Canada, using the far offset VSP survey. Existing surface seismic was used to infer that a well drilled into the interpreted North-east corner of the Ricinus reef would be successful in penetrating oil bearing carbonate reef. The well was drilled; however, the well missed the reef and a near and far offset VSP survey was used to seismically image possible reef buildups in an area around the well. The Fort St. John Graben case history (Hinds et al., 1991a; Hinds et al., 1993a) highlights exploration of a gas-filled channel sandstone using near and far offset (lateral) VSP surveys. An exploration well was drilled within the study area which intersected the target zone sandstone (the basal Kiskatinaw of the Upper Carboniferous). The target sandstone had a high shale content and was not reservoir quality. A near offset and two far offset VSP surveys were run in the exploration well to image out to a distance of 350 m to the North-west and to the East of the well. The VSP, surface seismic and geology results (from the geological logs of the exploration and surrounding wells) are integrated to infer a clearer picture of the sand/shale relationships of the basal Kiskatinaw and detailed faulting of the Carboniferous strata around the well and within the surface seismic line area. The Simonette field case history (Hinds et al., 1991 b; Hinds et al., 1993b) involves using VSP results to image the slope of a low-relief carbonate reef. The low-relief reef examined using the VSP data is located at the extreme end of a North-east reef spur of the Simonette Reef located in North-west Alberta, Canada. An exploration well drilled in the low-relief reef penetrated the edge of the reef. The VSP surveys were run in order to infer details of the reef slope. The interpretation of the VSP data was integrated with all other exploration data to infer the location of the crest of the low-relief reef and to assist in determining whether to whipstock the exploration well or not. / Thesis (DSc)--University of Pretoria, 2010. / Geology / unrestricted

The integrated processing and interpretation of VSP data are developed to work together in order to enhance the final VSP interpretation. Furthermore, the interpretive processing of the VSP data within the case histories are reviewed along with the incorporation of the final VSP results (both near and far offset data) into the integrated geological/geophysical interpretations presented in the case studies. This thesis has attempted to personify the term "interpreter/processor" as first highlighted in Hardage (1985). The case histories pertain to oil and gas exploration in carbonate reef and sandstones in the Western Canadian Sedimentary Basin (WCSB). The Lanaway case history (Hinds et al., 1994a) pertains to the exploration of the Lanaway/Garrington oil field located in central Alberta, Canada. The surface seismic interpretation over the reef crest differed dramatically from the isopach of the reef-encasing shales derived from the geological logs of a borehole drilled into the reef crest. To understand the discrepancy, a VSP survey was performed and the data were interpretatively processed. The results were integrated with the known geology of the field area to uncover possible reasons for the surface seismic anomaly. field in central Alberta, Canada, using the far offset VSP survey. Existing surface seismic was used to infer that a well drilled into the interpreted North-east corner of the Ricinus reef would be successful in penetrating oil bearing carbonate reef. The well was drilled; however, the well missed the reef and a near and far offset VSP survey was used to seismically image possible reef buildups in an area around the well. The Fort St. John Graben case history (Hinds et al., 1991a; Hinds et al., 1993a) highlights exploration of a gas-filled channel sandstone using near and far offset (lateral) VSP surveys. An exploration well was drilled within the study area which intersected the target zone sandstone (the basal Kiskatinaw of the Upper Carboniferous). The target sandstone had a high shale content and was not reservoir quality. A near offset and two far offset VSP surveys were run in the exploration well to image out to a distance of 350 m to the North¬west and to the East of the well. The VSP, surface seismic and geology results (from the geological logs of the exploration and surrounding wells) are integrated to infer a clearer picture of the sand/shale relationships of the basal Kiskatinaw and detailed faulting of• the Carboniferous strata around the well and within the surface seismic line area. The Simonette field case history (Hinds et al., 1991 b; Hinds et al., 1993b) involves using VSP results to image the slope of a low-relief carbonate reef. The low-relief reef examined using the VSP data is located at the extreme end of a North-east reef spur of the Simonette Reef located in North-west Alberta, Canada. An exploration well drilled in the low-relief reef penetrated the edge of the reef. The VSP surveys were run in order to infer details of the reef slope. The interpretation of the VSP data was integrated with all other exploration data to infer the location of the crest of the low-relief reef and to assist in determining whether to whipstock the exploration well or not. / Thesis (DSc)--University of Pretoria, 1994. / Geology / unrestricted

Conventional modeling and migration for tilted transversely isotropic (TTI) media may suffer from numerical instabilities and shear wave artifacts due to the coupling of the P-wave and SV-wave modes in the TTI coupled equations. Starting with the separated P- and SV-phase velocity expressions for vertical transversely isotropic (VTI) media, I extend these decoupled equations for modeling and reverse-time migration (RTM) in acoustic TTI media. Compared with the TTI coupled equations published in the geophysical literature, the new TTI decoupled equations provide a more stable solution due to the complete separation of the P-wave and SV-wave modes. The pseudospectral (PS) method is the most convenient method to implement these equations due to the form of wavenumber expressions and has the added benefit of being highly accurate and thus avoiding numerical dispersion. The rapid expansion method (REM) in time is employed to produce a broad band numerically stable time evolution of the wavefields. Synthetic results validate the proposed TTI decoupled equations and show that modeling and RTM in TTI media with the decoupled P-wave equation remain numerically stable even for models with strong anisotropy and sharp contrasts. The most desirable feature of the TTI decoupled P-wave equation is that it is absolutely free of shear-wave artifacts and the consequent alleviation of numerical instabilities generally suffered by some systems of coupled equations. However, due to several forward-backward Fourier transforms in wavefield extrapolation at each time step, the computational cost is also high, and thereby hampers its prevalence. I hereby propose to use a hybrid pseudospectral and finite-difference (FD) scheme to solve the TTI decoupled P-wave equation. In the hybrid solution, most of the cost-consuming wavenumber terms in the equation are replaced by inexpensive FD operators, which in turn accelerates the computation and reduces the computational cost. To demonstrate the benefit in cost saving of the new scheme, 2D and 3D RTM examples using the hybrid solution to the decoupled P-wave equation are carried out, and respective runtimes are listed and compared. Computation examples show that the hybrid strategy demands less computation time and is faster than using the pseudospectral method alone. Furthermore, this new hybrid TTI RTM algorithm is less computationally expensive than the FD solution to the conventional TTI coupled equations but more stable.

No description available.

Acquisition of 2D seismic profiles often serves as a prerequisite to the acquisition of the more robust and more expensive 3D seismic volumes. However, in basins such as the Illinois Basin where production is operated by small scale, often family-owned operators, 2D seismic data is relied upon as the primary source of an exploration program. This thesis is a case study of two 2D seismic profiles that were acquired in the Illinois Basin over an inferred carbonate mud-mound. In an effort to enhance the geologic interpretation of these commonly hydrocarbon-rich features, this thesis focuses on producing effective processing and interpretation workflows utilizing 2D seismic reflection data.A detailed processing workflow utilizing a standard processing sequence as well as advanced processing techniques designed to enhance the signal-to-noise ratio, vertical resolution, reflection sharpness, and reflection continuity of the 2D seismic data is conducted to prepare the data for interpretation. Interpretation techniques included a seismic-to-well tie where a good match was generated using an extracted wavelet from the two seismic profiles and the bulk density / sonic curves from an offset well. Seismic signal, complex trace, and stratigraphic seismic attributes were also computed using Schlumberger’s Petrel Seismic Interpretation package. The computation of seismic attributes on two seismic reflection profiles to reveal the subtle, inferred mud-mound appears useful in terms of a qualitative interpretation. Mound like structures frequently contain chaotic reflections, lateral and vertical variations in lithology, and draping of overlying strata. The following attributes computed on both seismic reflection profiles are determined to have value in terms of qualitative interpretation applications: the first derivative of amplitude, the second derivative of amplitude, reflection intensity, instantaneous phase, cosine of instantaneous phase, dominant frequency, and sweetness. The RMS amplitude, apparent polarity, instantaneous bandwidth, instantaneous frequency, and envelope (reflection strength) all have little qualitative value and/or produce the relatively same results as the aforementioned useful attributes.

Elevators serve a critical function in essential facilities such as hospitals and need to remain operational during and after earthquakes. However, they are still known to malfunction during earthquakes even after several design and sensing improvements required by the current code have been incorporated. Most of the damages were experienced or caused by the rail-counterweight system. Being the heaviest component of an elevator, the counterweight induced strong dynamic effects to the guiding system sometimes even collided and damaged the passenger car. A realistic analytical model of rail-counterweight system of an elevator that includes details of the supporting system is developed in this study. The nonlinearities caused by closing of the code specified clearances play an important role in determining the dynamic behavior of the system, and are thus included in this study. Also included are the acceleration inputs from different floor of building and the effect of different location of the counterweight along the guide rail. Parametric study is carried out to investigate the effect of different parameters on the seismic responses of the rail-counterweight system. In order to improve the seismic performance of the rail-counterweight system, several protective schemes are investigated. One simple approach is to increase the damping of the system using additional discrete viscous dampers. However, there is not much space available for installing the devices, and placement parallel to the spring at the roller guide assemblies is not quite effective due to contact between the restraining plate at the roller guide assemblies and the rail that makes the roller guides ineffective. Another method is to convert the top part of the weights into a tuned mass damper. This method can reduce the maximum stress in the rail if designed properly. The effectiveness of the passive tuned mass damper can be improved further by using it in an active mode by installing an actuator between the mass damper and the counterweight frame. The numerical results that confirm the effectiveness of such an active tuned mass damper are presented. As an alternative to the fully active control scheme, a semi-active control scheme using a magnetorheological damper device between the mass damper and the frame is also studied. This control approach is found to be as effective in reducing the seismic response as a fully active scheme. Since this MR damper can be operated using a simple battery, the external power requirements for implementation of this approach are quite minimal. / Ph. D.