This project is a continuation of earlier research work by the Principal Investigator in support of the Earthquake Engineering Research Program, under the direction of the USAE Waterways Experiment Station at Vicksburg, Mississippi. The program of experiments investigating the earthquake behavior and liquefaction of deep sand deposits has generated a large body of data for analysis. This Final Technical Report describes the database that has been developed to date and presents the analysis and the initial conclusions of the study. Data of excess pore pressures at different depths is used to deduce the onset of liquefaction under different initial effective overburden stresses. The object of the research is to compute the factor K(sigma), widely used in design calculations to relate the liquefaction resistance at high effective confining stresses to the strength deduced from laboratory experiments at 1 tsf. By comparing the data obtained from the centrifuge experiments with standard design approaches for the prediction of liquefaction, an assessment of the relationship between K(sigma) and depth can be made. This is discussed and areas where further experimental work is required are highlighted. The results are also presented in the form of log-log (stress focus) plots and compared with laboratory element test data. Preliminary conclusions indicate that the centrifuge data more closely match relationships based on field experience than laboratory data.

This project is a continuation of earlier research work by the Principal Investigator in support of the Earthquake Engineering Research Program, under the direction of the USAE Waterways Experiment Station at Vicksburg, Mississippi. The program of experiments investigating the earthquake behavior and liquefaction of deep sand deposits has generated a large body of data for analysis. This Final Technical Report describes the database that has been developed to date and presents the analysis and the initial conclusions of the study. Data of excess pore pressures at different depths is used to deduce the onset of liquefaction under different initial effective overburden stresses. The object of the research is to compute the factor K(sigma), widely used in design calculations to relate the liquefaction resistance at high effective confining stresses to the strength deduced from laboratory experiments at 1 tsf. By comparing the data obtained from the centrifuge experiments with standard design approaches for the prediction of liquefaction, an assessment of the relationship between K(sigma) and depth can be made. This is discussed and areas where further experimental work is required are highlighted. The results are also presented in the form of log-log (stress focus) plots and compared with laboratory element test data. Preliminary conclusions indicate that the centrifuge data more closely match relationships based on field experience than laboratory data.

The hazard posed by large dams has long been known. Although no concrete dam has failed as a result of earthquake activity, there have been instances of significant damage. Concerns about the seismic safety of concrete dams have been growing recently because the population at risk in locations downstream of major dams continues to expand and because the seismic design concepts in use at the time most existing dams were built were inadequate. In this book, the committee evaluates current knowledge about the earthquake performance of concrete dams, including procedures for investigating the seismic safety of such structures. Earthquake Engineering for Concrete Dams specifically informs researchers about state-of-the-art earthquake analysis of concrete dams and identifies subject areas where additional knowledge is needed.

"In order to reduce the seismic risk facing many densely populated regions worldwide, including Canada and the United States, modern earthquake engineering should be more widely applied. But current literature on earthquake engineering may be difficult to grasp for structural engineers who are untrained in seismic design. In addition no single resource addressed seismic design practices in both Canada and the United States until now. Elements of Earthquake Engineering and Structural Dynamics was written to fill the gap. It presents the key elements of earthquake engineering and structural dynamics at an introductory level and gives readers the basic knowledge they need to apply the seismic provisions contained in Canadian and American building codes."--Résumé de l'éditeur.

This report describes the initial findings of an experimental study supported by the U.S. Army Centrifuge Research Center and Engineer Earthquake Engineering Research Program (EQEN) into the behavior of saturated sands under high initial effective confining stresses subjected to strong ground shaking. The research was conducted using the Army Centrifuge at the U.S. Army Engineering Research and Development Center (ERDC), located in Vicksburg MS, formerly known as the Waterways Experiment Station (WES). The centrifuge studies have shown that the generation of excess pore pressure is limited to a level less than 100 percent for vertical effective confining stresses exceeding around 3 atmospheres (atm, or 300 KPa). This limit reduces at higher confining stresses. It is likely that this limit is a function of a range of variables, including amplitude of shaking. A second key finding indicates that dense layers overlying loose layers may still be readily liquefied as a consequence of the high excess pore pressures generated below. If verified, the potential benefits from these findings for the design of remediation works for large earth dams could be substantial. The report describes the equipment used for the experiments, the research program, and presents the initial results, contrasting the development of excess pore pressure at low confining stress with that at high confining stress. Possible consequences for a hypothetical dam are discussed.

Fundamentals of Earthquake Engineering combines aspects of engineering seismology, structural and geotechnical earthquake engineering to assemble the vital components required for a deep understanding of response of structures to earthquake ground motion, from the seismic source to the evaluation of actions and deformation required for design. The nature of earthquake risk assessment is inherently multi-disciplinary. Whereas Fundamentals of Earthquake Engineering addresses only structural safety assessment and design, the problem is cast in its appropriate context by relating structural damage states to societal consequences and expectations, through the fundamental response quantities of stiffness, strength and ductility. The book is designed to support graduate teaching and learning, introduce practicing structural and geotechnical engineers to earthquake analysis and design problems, as well as being a reference book for further studies. Fundamentals of Earthquake Engineering includes material on the nature of earthquake sources and mechanisms, various methods for the characterization of earthquake input motion, damage observed in reconnaissance missions, modeling of structures for the purposes of response simulation, definition of performance limit states, structural and architectural systems for optimal seismic response, and action and deformation quantities suitable for design. The accompanying website at www.wiley.com/go/elnashai contains a comprehensive set of slides illustrating the chapters and appendices. A set of problems with solutions and worked-through examples is available from the Wley Editorial team. The book, slides and problem set constitute a tried and tested system for a single-semester graduate course. The approach taken avoids tying the book to a specific regional seismic design code of practice and ensures its global appeal to graduate students and practicing engineers.

Over the life of a structure, the smaller but more frequent earthquakes contribute more to the cumulative damage than the larger earthquakes on which structural design is traditionally based. This is a quantitative argument in favour of designing structures beyond what the codes require for life-safety. This book presents a computational method to evaluate the damage sustained by a building over its lifetime in a seismic environment. The ability to estimate future damage is relevant to a pair of current trends in earthquake engineering: a growing interest for preventing damage on top of protecting the public, and development of performance-based design. The proposed method combines probabilistic principles with traditional structural analysis, which makes it readily applicable to evaluation of planned structures in an engineering office. The analytical models, computational steps and supporting data used to produce an estimate of damage are discussed, and variants of the method with different run time and accuracy are considered. As an example of application to structural design, the book proposes a method to optimise placement of viscous dampers in buildings by minimising a life-cycle cost that includes the investment in damping and the losses due to future damage. Along with the results obtained in the course of other examples, the optimal solutions support a shift toward more resilient structures designed to mitigate structural and nonstructural damage beyond the traditional life-safety requirements.