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This dissertation presents the results of a research effort conducted to better understand the seismic performance and analysis of pile-supported wharves. Given the limited number of well-documented field case histories, the seismic performance of pile-supported wharves has been poorly quantified, and the analysis methods commonly employed in engineering practice have generally not been validated. Field case histories documenting the seismic performance of pile-supported wharves commonly contain only limited information, such as approximations of wharf and embankment deformations and peak ground surface accelerations. In order to supplement the field data, five centrifuge models were dynamically tested, with each model containing close to 100 instruments monitoring pile bending moments, excess pore pressures, displacements, and accelerations. The combined field and model database was used to develop seismic performance relationships between permanent lateral deformations, maximum and residual bending moments and peak ground surface displacements. Key issues such as the seismic performance of batter piles, the development of large moments at depth, and the need to account for permanent lateral deformations for high levels of shaking, even for very stable geometries, are discussed. The field data and model studies were also used to validate two geotechnical seismic performance analysis methods: 1) the limit-equilibrium based rigid, sliding block (Newmark) method, and 2) an advanced finite-difference effective stress based numerical model (FLAC). Favorable predictions were generally obtained for both methods, yet there was a large variability in the results predicted using the rigid, sliding block method. The numerical model predicted the permanent deformations, pore pressure generation, and accelerations fairly well, however, pile bending moments were poorly predicted. The results of this research clearly highlighted the need for analysis validation studies, and note the uncertainty and variability inherent in the seismic performance of complex structures. The lack of adequate validation may lead to an over-confidence and false sense of security in the results of the seismic analysis methods. This dissertation specifically addresses pile-supported wharves, yet the results presented herein are applicable to other pile-supported structures located near, or on, slopes adjacent to the waterfront, such as: bridge abutments, railroad trestles, and pile-supported buildings near open slopes. Performance and analysis issues common to all of these structures are addressed, such as: liquefiable soils, lateral pile response in horizontal and sloping soils, the lateral behavior of piles in rock fill, and global slope stability, as well as the general observed seismic behavior. / Graduation date: 2004

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 111-121). Also available on the World Wide Web.

University of Macau / Faculty of Science and Technology / Department of Civil and Environmental Engineering

The goal of this study is to design and evaluate economic and rapid seismic retrofit strategies for relatively small rehabilitation projects for steel structures consistent with the tenets of sustainable design. The need to retrofit existing structures in earthquake prone regions may arise directly from the problem of aging and deteriorating conditions, recognition of the vulnerability of existing infrastructure, from updates in seismic code requirements, or changes in building performance objectives. Traditional approaches to seismic hazard mitigation have focused reducing the failure probabilities, consequences from failures, and time to recovery. Such paradigms had been established with little regard to the impact of their rehabilitation measures on the environment and disruptions to occupants. The rapid rehabilitation strategies proposed here have sustainability benefits in terms of providing a more resilient building stock for our communities as well as minimizing environmental and economical impacts and social consequences during the rehabilitation project. To achieve these goals, a unique approach to design supplemental systems using tension-only elements is proposed. In this design approach undesirable global and local buckling are eliminated. Two rapid rehabilitation strategies are presented. The first is a bracing system consisting of cables and a central energy dissipating device (CORE Damper). The second is a shear wall system with the combined use of thin steel plate and tension-only bracing. Analytical studies using both advanced and simplified models and proof-of-concept testing were carried out for the two devices. The results demonstrated stable, highly efficient performance of the devices under seismic load. Preliminary applications of the CORE damper to the retrofitting of a braced steel frame showed the ability of the system to minimize soft story failures. Both techniques can be implemented within a sustainability framework, as these interventions reduce the seismic vulnerability of infrastructure, are low cost, utilize materials and fabrication processes widely available throughout the world, can be handled by unskilled labor and carried out with minimal disruptions to the environment. The approach taken in this study can provide a road map for future development of sustainability-based rehabilitation strategies.

Three buildings in Montreal and three buildings in Vancouver were designed for different level of "ductility" according to the 1985 National Building Code of Canada and the 1984 Canadian Concrete Code. / Three full scale reinforced concrete specimens representing an exterior beam-column-slab subassemblage of the Montreal structure were tested in order to determine the behaviour of these components. The role of the spandrel beam in limiting the effective slab width and its role in transferring shear to the joint region was investigated. / Analytical procedures were developed in order to predict the responses of main structural components to the combined loading effects of axial load, moment and shear. In addition a hysteretic behavioural model was developed in order to account for strength and stiffness degradation as well as pinching of the hysteretic response. / The analytical procedures were then used to model the responses of the components of these buildings. Non-linear dynamic analyses were carried out on each building for a series of artificially generated accelerograms. The results of the tests as well as the results of the non-linear dynamic analyses enabled an assessment of the performance of different building designs and an assessment of current code requirements.

This dissertation contains investigations of radiated seismic energy measurements from large earthquakes and duration determinations as significant properties of the dynamic earthquake rupture and its applications in the identification of very large and slow source rupturing earthquakes. This includes a description of earthquake released seismic energy from 1997 to 2010 and identification of slow source tsunami earthquakes in that time period. The implementation of these measurements in real-time since the beginning of 2009, with a case study of the Mentawai 2010 tsunami earthquake are also discussed. Further studies of rupture duration assessments and its technical improvements for more rapid and robust solutions are investigated as well, with application to the Tohoku-Oki 2011 earthquake an a case of directivity in the 2007 Mw 8.1 Solomon islands earthquake. Finally, the set of routines and programs developed for implementation at Georgia Tech and IRIS to produce the real-time results since 2009 presented in this study are described.

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [112]-124).

This dissertation is a comprehensive summary of four papers on the development and application of new strategies for locating tremor and relocating events in earthquake catalogs. In the first paper, two new strategies for relocating events in a catalog are introduced. The seismicity pattern of an earthquake catalog is often used to delineate seismically active faults. However, the delineation is often hindered by the diffuseness of earthquake locations in the catalog. To reduce the diffuseness and simplify the seismicity pattern, a relocation and a collapsing method are developed and applied. The relocation method uses the catalog event density as an a priori constraint for relocations in a Bayesian inversion. The catalog event density is expressed in terms of the combined probability distribution of all events in the catalog. The collapsing method uses the same catalog density as an attractor for focusing the seismicity in an iterative scheme. These two strategies are applied to an aftershock sequence after a pair of earthquakes which occurred in southwest Iceland, 2008. The seismicity pattern is simplified by application of the methods and the faults of the mainshocks are delineated by the reworked catalog. In the second paper, the spatial distribution of seismicity of the Hengill region, southwest Iceland is analyzed. The relocation and collapsing methods developed in the first paper and a non-linear relocation strategy using empirical traveltime tables are used to process a catalog collected by the Icelandic Meteorological Office. The reworked catalog reproduces details of the spatial distribution of seismicity that independently emerges from relative relocations of a small subset of the catalog events. The processed catalog is then used to estimate the depth to the brittle-ductile transition. The estimates show that in general the northern part of the area, dominated by volcanic processes, has a shallower depth than the southern part, where tectonic deformation predominates. In the third and the fourth papers, two back-projection methods using inter-station cross correlations are proposed for locating tremor sources. For the first method, double correlations, defined as the cross correlations of correlations from two station pairs sharing a common reference station, are back projected. For the second method, the products of correlation envelopes from a group of stations sharing a common reference station are back projected. Back projecting these combinations of correlations, instead of single correlations, suppresses random noise and reduces the strong geometrical signature caused by the station configuration. These two methods are tested with volcanic tremor at Katla volcano, Iceland. The inferred source locations agree with surface observations related to volcanic events which occurred during the tremor period.

Quantitative and qualitative assessment of the seismic risk to highway bridges is crucial in pre-earthquake planning, and post-earthquake response of transportation systems. Such assessments provide valuable knowledge about a number of principal effects of earthquakes such as traffic disruption of the overall highway system, impact on the regions' economy and post-earthquake response and recovery, and more recently serve as measures to quantify resilience. Unlike previous work, this study captures unique bridge design attributes specific to California bridge classes along with their evolution over three significant design eras, separated by the historic 1971 San Fernando and 1989 Loma Prieta earthquakes (these events affected changes in bridge seismic design philosophy). This research developed next-generation fragility curves for four multispan concrete bridge classes by synthesizing new knowledge and emerging modeling capabilities, and by closely coordinating new and ongoing national research initiatives with expertise from bridge designers. A multi-phase framework was developed for generating fragility curves, which provides decision makers with essential tools for emergency response, design, planning, policy support, and maximizing investments in bridge retrofit. This framework encompasses generational changes in bridge design and construction details. Parameterized high-fidelity three-dimensional nonlinear analytical models are developed for the portfolios of bridge classes within different design eras. These models incorporate a wide range of geometric and material uncertainties, and their responses are characterized under seismic loadings. Fragility curves were then developed considering the vulnerability of multiple components and thereby help to quantify the performance of highway bridge networks and to study the impact of seismic design principles on the performance within a bridge class. This not only leads to the development of fragility relations that are unique and better suited for bridges in California, but also leads to the creation of better bridge classes and sub-bins that have more consistent performance characteristics than those currently provided by the National Bridge Inventory. Another important feature of this research is associated with the development of damage state definitions and grouping of bridge components in a way that they have similar consequences in terms of repair and traffic implications following a seismic event. These definitions are in alignment with the California Department of Transportation's design and operational experience, thereby enabling better performance assessment, emergency response, and management in the aftermath of a seismic event. The fragility curves developed as a part of this research will be employed in ShakeCast, a web-based post-earthquake situational awareness application that automatically retrieves earthquake shaking data and generates potential damage assessment notifications for emergency managers and responders. / Errata added at request of advisor and approved by Graduate Office, March 15 2016.