Adjacent buildings subjected to seismic excitations collide against each other when the separation distance is not large enough to accommodate the displacement response of the structures relative to one another. As shown by field observations and by numerical models, seismic pounding can cause severe damage on the affected structures. While these undesirable effects can be prevented by providing adequate separation distances, implementation of generous separations is not possible in metropolitan areas because of maximization of land usage. First, an extensive review of the current state-of-the-art on pounding and on mitigation with a connector linking adjacent structures is made. The only conclusion shared by the researchers is that the effect of pounding on the response of the structure is a very complex one, depending on various parameters of the structures and the characteristics of the ground motion. Due to high complexities of the pounding problems, assumptions have to be made. Most of the researchers have used single-degree-of-freedom systems but this model cannot represent the formation of a storey mechanism or the impact between slab and column. Another assumption generally made is to model linear structure. However, the author found that when pounding occurs, a structure entering in the plastic domain cannot generally be adequately represented by an elastic model. Various assumptions and restrictions are applied to these models. Non-linear direct time history analyses are realized with three artificial accelerograms. The problem has been reduced to a two-dimensional one. The interaction between soil and structure has been neglected. The structures studied have been designed according to Eurocodes [EC8, EC2] for a peak ground acceleration of 0,4g, 0,25g and 0,10g. Beams and columns are idealized as distinct elements and all inelastic deformations are considered concentrated at their two ends (point hinge models). Contact points are known a priori and located at each slab of the buildings. The Kelvin model, a spring and a dashpot used in combination with a gap element, is used in SAP 2000 program to simulate the pounding phenomenon. The pounding effects are first studied. The study concerns adjacent structures having same and different total height and (non)aligned floor levels. It was found difficult to give rules to anticipate the response of the adjacent buildings. This is due to the complex but necessary non-linear behaviour of pounding and structures. In short, pounding amplifies the displacements and the shear action effects of the impacted buildings. These effects can lead to serious damage caused by P-Delta effects or by shear brittle failure. As expected, pounding phenomenon is found to be very dangerous for buildings having non-aligned floor levels. The second part of the work studied the use of connections between adjacent buildings. The study consists in exploring problems and solutions in order to provide guidance to designers. Following the numerical simulations, a practical guide is presented to assist engineers in the choice of the adequate type and properties for the reconnection with reference to the characteristics of the structures submitted to pounding and to their stand-off distances.

<p>The present study focuses on delineation of the southern edge of the middle Devonian Prairie Evaporite (PE) in south-central Saskatchewan. The purpose of this work was to improve the accuracy and resolution of subsurface mapping by including additional information from well logs and seismic data not included in the previous studies.</p><p>Approximately 330 km of 2-D seismic data were integrated with horizon picks from 1334 well logs to improve the delineation of the southern margin of the PE. Thirteen seismic lines were re-processed with an emphasis on high-frequency imaging. The resulting seismic sections show marked improvement in the accuracy and resolution of mapping of the PE salt edges, with the estimated depth resolution improved to ~15 m. Seismic data indicate that salt dissolution structures were created by multistage processes. Salt collapses were identified within the body of the Prairie Evaporite and off-salt.</p><p>Well log data were combined with seismic results and gridded to create an updated map of the Prairie Evaporite. Different gridding methods provided different interpolations of the data set, particularly where the salt layer is thin near its margin. Incorporation of seismic interpretations resulted in 2-9 km changes in the positions of the salt edges derived earlier from well log and limited seismic interpretations. Therefore, integration of the seismic and well log data should increase the accuracy of the positions of the salt edge.</p><p>In order to evaluate the effects of the basin fill on regional gravity signatures and to determine whether the effect of the salt edge could be observed in gravity data, two gravity profiles crossing the salt collapse margin and the Trans-Hudson Orogen and the Wyoming Structural Province were analysed. Regional-scale gravity modeling showed that the transition from the Trans-Hudson Orogen to Wyoming Province was marked by deep-seated structures within the basemen. Detailed gravity modeling of a shorter profile well-constrained by seismic data showed that the salt collapses contribute ~0.4 mgal to the total anomaly of about 4 mgal. Although a direct observation of salt edge by gravity appears hardly feasible, performing high-resolution gravity survey with station interval ~100 m might still be useful to constrain the overburden and thereby help detect salt collapses.

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.

<p>The present study focuses on delineation of the southern edge of the middle Devonian Prairie Evaporite (PE) in south-central Saskatchewan. The purpose of this work was to improve the accuracy and resolution of subsurface mapping by including additional information from well logs and seismic data not included in the previous studies.</p><p>Approximately 330 km of 2-D seismic data were integrated with horizon picks from 1334 well logs to improve the delineation of the southern margin of the PE. Thirteen seismic lines were re-processed with an emphasis on high-frequency imaging. The resulting seismic sections show marked improvement in the accuracy and resolution of mapping of the PE salt edges, with the estimated depth resolution improved to ~15 m. Seismic data indicate that salt dissolution structures were created by multistage processes. Salt collapses were identified within the body of the Prairie Evaporite and off-salt.</p><p>Well log data were combined with seismic results and gridded to create an updated map of the Prairie Evaporite. Different gridding methods provided different interpolations of the data set, particularly where the salt layer is thin near its margin. Incorporation of seismic interpretations resulted in 2-9 km changes in the positions of the salt edges derived earlier from well log and limited seismic interpretations. Therefore, integration of the seismic and well log data should increase the accuracy of the positions of the salt edge.</p><p>In order to evaluate the effects of the basin fill on regional gravity signatures and to determine whether the effect of the salt edge could be observed in gravity data, two gravity profiles crossing the salt collapse margin and the Trans-Hudson Orogen and the Wyoming Structural Province were analysed. Regional-scale gravity modeling showed that the transition from the Trans-Hudson Orogen to Wyoming Province was marked by deep-seated structures within the basemen. Detailed gravity modeling of a shorter profile well-constrained by seismic data showed that the salt collapses contribute ~0.4 mgal to the total anomaly of about 4 mgal. Although a direct observation of salt edge by gravity appears hardly feasible, performing high-resolution gravity survey with station interval ~100 m might still be useful to constrain the overburden and thereby help detect salt collapses.

No description available.

The purpose of this study is to examine the sediment stratigraphy and oyster reefs of Lavaca Bay. There has been little previous research on the bay??s stratigraphy, and information from this study is important for industry and resources management. The Lavaca Bay estuary is a drowned river valley containing a history of estuary development in the late Pleistocene and Holocene. We used a chirp sonar to gather acoustic reflection profiles, which were classified to categorize and trace reflectors. The data were plotted to make maps of the distribution of various reflection types and contour maps of reflector surfaces. The maps were compared with previous studies of Lavaca Bay and Galveston Bay to aid interpretation. The vertical sediment stratigraphy showed two main reflector packages. The upper package, bay bottom to ~25 m depth, is mostly acoustically transparent with a few, semi-continuous, prominent reflectors in the upper 5-10 m. The lower package ranges from 15-40 m depth with several strong reflectors sometimes underlain by unconformities. To classify reflector characteristics, the upper package was divided into two categories, each with 4 sub-categories: 1) surface reflectors??weak, medium, strong, and ringing, which describe the general acoustic return of the bay bottom, and 2) strong, shallow reflectors??surface strong, mounds, buried strong, andburied multiples, which describe strong acoustic returns in the upper 5 m of stratigraphy. Within the lower package, four categories were recognized: 1) subbottom reflectors/horizons, occurring ~20-40 m depth, 2) deep wipeout (incoherent/wipeout zone), ~10-30 m depth, 3) clinoforms, ~5-30 m depth, and 4) terraces, ~10-30 m depth. The data interpretation agrees with previous studies suggesting Lavaca Bay filled beginning with coarse sediment and grading to finer sediment. In addition, the surface type reflectors are indicative of bottom type, the strong, shallow reflectors are largely indicative of oyster reef/shell, and the subbottom reflectors are related to the Pleistocene and bay fill. The location/extent of oyster reefs in the bay does not agree well with previous studies, suggesting either oysters do not grow over older ones or differences between the chirp sonar response and other methods significantly differentiate the interpretation of their locations/extents.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (M.S.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Steven R. Baker, Thomas G. Muir. Includes bibliographical references (p. 63-65). Also available online.

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xxxviii, 372 p.; also includes graphics (some col.). Includes abstract and vita. Advisor: Jeffrey J. Daniels, Dept. of Geological Sciences. Includes bibliographical references (p. 362-372).