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Ground Motion Characteristics Of The San Francisco Bay Area Detected By Microtremor Measurements, T. Ohmachi, Y. Nakamura, T. Toshinawa

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Microtremor measurement was done mainly in the damaged areas in San Francisco and Oakland after the 1989 Loma Prieta earthquake. The observation areas were (1) the Marina District, (2) Cypress Street, (3) the Embarcadero, and (4) South of Market District. Predominant frequency (Fp) and amplification factor (Ap) obtained from a spectral ratio between horizontal and vertical components were evaluated for each observation cite. Difference in the degree of damage in the areas (1) and (4) was coincident with difference in Ap and Fp. Significant difference could not be found in Ap and Fp between the areas (2) and (3).

Investigation Of Sanitary Landfill Slope Performance During Strong Ground Motion From The Loma Prieta Earthquake Of October 17, 1989, Mervin E. Johnson, Joan Lundy, Marshall Lew, Monte E. Ray

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

This paper evaluates the performance of landfill slopes (refuse fill slopes) during strong ground motion from the October 17, 1989 Loma Prieta Earthquake (M7.1) that affected the Santa Cruz Mountains - San Francisco Bay region. The earthquake's occurrence in a highly populated area that contains the waste disposal sites for this large population offered a unique opportunity to review the performance of slopes on the landfills. Current state and federal regulations require the analysis of stability of landfills under seismic loading. To date, these evaluations have relied on gross simplified assumptions. This paper examines whether these assumptions are reasonably correct. …

Liquefaction And Surface Settlement In The Marina District, D. Rosidi, W. B. Wigginton

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

This paper evaluates the liquefaction potential of sands within the Marina District. Three types of underlying potentially liquefiable soil deposits are studied: (A) Hydraulic fill, (B) Artificial fill, and (C) Strawberry Island and other modern beach deposits. A liquefaction analysis for each of these deposits is conducted. It is suggested that a Peak Ground Acceleration (PGA) of approximately 0.1g is needed in the Marina District to initiate liquefaction. Relations between PGA and thickness of liquefiable soil, as well as potential surface settlement are presented. These relationships are useful for the study of expected performance of the Marina District in future …

On The Site Amplification Characteristics In San Francisco Bay Region Due To The 1989 Loma Prieta Earthquake Type Loadings, Kesuke Baba, Yutaka Inoue, Takashi Nishigaki

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

A large earthquake occurred in the Santa Cruz mountains, California, on 17 October 1989, and many structures and facilities in the San Francisco Bay region suffered fatal damage from the seismic motion. In order to evaluate the ground amplification characteristics in the region, the practical method of representing the seismic wave field may be necessary. This paper is concerned with a theoretical analysis and numerical evaluation based on the wave propagation theory to find the dynamic characteristics of the slightly sedimental basin around the San Francisco Bay due to the Loma Prieta earthquake type excitations. Numerical examples of this system …

Sanitary Landfill Performance During The Loma Prieta Earthquake, Dennis Buranek, Sangeeta Prasad

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The October 17, 1989, Loma Prieta earthquake subjected a number of solid waste or sanitary landfills to significant shaking. The performance of sanitary landfills during large earthquakes is of great interest to the public, state and federal agencies, and the landfill owners. The observed performance of six sanitary landfills located within the Lorna Prieta earthquake damage zone is compared with the performance predicted by a commonly used deformation analysis technique. The six landfills were inspected immediately after the October 17, 1989, magnitude 7.1 earthquake. Damage and evidence of slope movement, or lack thereof, was recorded. The mean peak ground accelerations …

Seismic Design Basis — The Uk Regulatory Position For New Nuclear Reactors, C. M. Patchett, R. J. Stubbs

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The purpose of this paper is to outline the seismic regulatory requirements relating to the site licensing of new nuclear power installations in the UK, and to describe the background and justification of the seismic design basis level for such installations. It outlines the potential seismic related hazards which should be covered, the factors which are considered important in establishing the level of hazard under consideration, and the techniques which could be used for hazard evaluation. In addition, the paper covers the level of uncertainty associated with the methodology and analytical techniques used in evaluating the seismic hazards.

Site Effects In The Loma Prieta Earthquake And Comparison With An Earthquake Intensity Prediction Method, Hatukazu Mizuno, Akio Abe

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Strong motion records of the Loma Prieta Earthquake of October, 17, 1989 have been analyzed in comparison with epicentral distances and types of soil deposits, and site effects and attenuation relations have been studied. Site effects are significantly recognized in the earthquake, as usually found in Japanese earthquakes. And validity of the U.S. seismic intensity prediction method that Association of Bay Area Governments (ABAG) adopted to prepare some earthquake preparedness maps has been examined on the basis of the Loma Prieta Earthquake data. Finally, soil damping of San Francisco Bay Area has been evaluated from the strong motion records.

The Liquefaction Sand Boils In The San Francisco Marina District During The 1989 Loma Prieta Earthquake, J. P. Bardet, M. Kapuskar

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The paper presents and analyzes the observations of the sand boils that emerged in the Marina District after the Loma Prieta Earthquake of October 17, 1989. The sand boils left behind by liquefaction revealed an old lagoon, the periphery of which had experienced severe damage in the 1906 San Francisco earthquake. The buildings in the Marina District were damaged primarily as the liquefied ground spread laterally along the shoreline of the 1906 lagoon that was filled to host the 1915 Panama-Pacific International Exposition in San Francisco. The present work infers that the sand boils are not random phenomena but instrumental …

Centrifuge Modeling For Dynamic Geotechnical Studies, R. S. Steedman

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The field of dynamic centrifuge modelling has developed rapidly over the past decade, with international interest in both earthquake and blast modelling. The paper discusses the proliferation of facilities and the insight that can be gained from the interpretation of dynamic model test data now available using hand calculations and advanced techniques of digital signal processing.

Constitutive Modelling Of Soils And Computation Of Earthquake Damage And Liquefaction, O. C. Zienkiewicz, M. Pastor, Y. M. Xie

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

For realistic modelling oi deformation and collapse of soil structures, an accurate constitutive model for the soil materials is necessary. In this paper we shall show i) how such very successful models can be obtained by the use of generalized plasticity theory; ii) the modification of such models for semi-saturated behavior; and finally iii) How incorporation of such models into a two phase computer program allows the solution of complex problems. A possible mode of failure of the San Fernando dam is included. This paper is divided into three parts according to the above.

Earthquake Geotechnology In Offshore Structures, R. G. Bea

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Current developments in earthquake geotechnology in offshore structures are summarized. These developments include measurements of sea floor and platform motions induced by earthquakes and analyses of platform structure and foundation systems. Results from these recent developments are illustrated.

Field And Laboratory Determination Of Soil Properties At Low And High Strains, R. D. Woods

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Over the past quarter century many testing methods have been used to determine soil properties for dynamic analysis. Most methods had been established by the time of the writer's review (Woods, 1978), and since then, changes have been mostly evolutionary. Many field and laboratory techniques are represented in papers submitted to this conference and these are reviewed, but additional citations from literature in the intervening years has been included for completeness. No claim is made that all pertinent literature is included, but that most methods of field and laboratory testing methods are covered with representative citations.

Flow Failure Of Liquefied Sand In Large-Scale Shaking Tables, Kenji Ishihara, Mikio Takeuchi

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Laboratory studies on flow failure in liquefied sand deposits using large-scale shaking tables are briefly introduced, together with a case study on the lateral deformation in the field. The key parameters influencing the occurrence of flow-type deformation are discussed in an effort to figure out a mechanism or scenario of the flow failure. In one series of the laboratory studies, shaking table tests were performed to examine the effectiveness of a preventive measure against the flow slide. This aspect is also discussed briefly.

Piles Under Dynamic Loads, M. Novak

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The paper deals with some of the more recent developments in pile dynamics. It reviews the progress in the analysis of single piles and pile groups, field as well as laboratory experiments and soil-pile-structure interaction. The influence of pile-soil interface is discussed and extensive references are given.

Seismic Amplification In The Presence Of Geological And Topographic Irregularities, E. Faccioli

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Following some introductory remarks on the key aspects of seismic site effects evaluation and on new data of special interest from recent earthquakes, the first part of the paper discusses and compares the performance of numerical 2D and 1D models, as well as of simple exact solutions, in problems of local soil response and of topographic amplification. The second part is devoted to the illustration of a very promising computational tool, i.e. the Fourier (or pseudo spectral) method, for time-domain analyses of seismic wave propagation in heterogeneous elastic media.

Earthquake Probabilities On The New Madrid Fault And The Impact Of Loma Prieta On Central U.S. Earthquake Preparedness, David Stewart

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Reliable probabilities of future damaging earthquakes in the New Madrid Fault Zone for purposes of mitigation and response planning are not available, even though considerable thought and research has gone into this question. Generalizations sufficient for pre-earthquake planning do exist, however, which suggest the need to prepare for at least a 50% chance of a 6.0 surface wave magnitude event within a decade, but that a repeat of the massive 8.0 magnitude events of 1811-12 need not be of concern for at least another century or two. The Loma Prieta was a significant stimulus toward greater earthquake planning and preparation …

Fault Processes And Liquefaction In The Marine Environment, Ronald C. Chaney

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

No abstract provided.

Panel Reports: Discussions, Multiple Authors

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

No abstract provided.

Soil-Pile Interaction Model For Earthquake Response Analysis Of Offshore Pile Foundations, Toyoaki Nogami

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

No abstract provided.

Second International Conferences On Recent Advances On In Geotechnical Earthquake Engineering And Soil Dynamics, Multiple Authors

International Conference on Case Histories in Geotechnical Engineering

No abstract provided.

Past Proceedings: Second International Conference On Recent Advances In Geotechnical Earthquake Engineering And Soil Dynamics, St. Louis (1991), Multiple Authors

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

No abstract provided.

Table Of Contents, Multiple Authors

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

No abstract provided.

An Estimation Of Dynamic Properties Of Soils From Block Vibration Tests, V. D. Miglani

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The paper presents departures that have to be made in the conduct of block vibration tests from the standard method and in the analysis of test data under unusual conditions. Disturbed soil condition under an edge of the block leads to occurrence of double peaks in amplitude versus frequency curves from vertical vibration test. Two methods have been devised to analyze such double peaks. The first method assumes a correlation between dynamic coefficients. The dynamic properties can be predicted from non-dimensional curves of correction factor versus ratio of effective base area. The second method assumes linear variation of coefficient of …

Behavior Of A Geosynthetic Reinforced Sand, H. C. Liu, N. Y. Chang

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The method of geosynthetic reinforced earth incorporates a flexible but tension resistant synthetic material in soil to increase the tensile resistance of the composite. In this study, both static and dynamic responses of an Ottawa 30-40 sand reinforced with a nonwoven geosynthet1c, Bidim C-34, were investigated. Static triaxial tests were first conducted to examine the influence of the reinforcement on strength, Young's modulus, and Poisson's ratio of the composite soil. Cyclic triaxial tests and resonant column tests were then conducted to examine the variation of shear modulus and damping ratio at different strain amplitudes. The influence of geosynthetic on both …

Session 1: Closing Remarks, M. Pastor

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

No abstract provided.

Energy-Absorbing Ability Of Texsol, Phong M. Luong

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Texsol is a 30 soil-fiber composite, obtained using a technique of soil reinforcement by incorporation of continuous textile fibers. The overall mechanical properties of Texsol result therefore from those of its components: soil and fibers. An experimental approach has been carried out in order to grasp the basic aspects of the stress-strain response of Texsol subjected to monotonic, cyclic and vibratory loadings. The study confirms that the application of Texsol to earthquake resistant earthworks and traffic structures could be of great interest and particularly suitable as shown by its ductility and energy-absorbing capacities that are readily evidenced by the laboratory …

GMax From Pressuremeter Tests: Theory; Chamber Tests; And Field Measurements, Peter M. Byrne, Francisco Salgado, J. A. Howie

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

A method of analysis to predict the in situ maximum shear modulus G_max,0 from self-boring pressuremeter unload tests is presented. The method considers both the stress and void ratio changes induced by pressuremeter loading and the nonlinear stress-strain response upon unloading. The results are presented in the form of a chart that allows G_max,0 to be determined from the equivalent elastic unload modulus, G*, for a wide range of loading and unloading conditions. The analysis procedure is checked with chamber tests and field data and the results are found to be in good agreement provided factors to account …

Modeling The Monotonic And Cyclic Viscoplastic Soil Behavior, Ronaldo I. Borja

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

We describe a class of viscoplastic constitutive models capable of simulating the monotonic and cyclic rate-dependent soil behavior. These models are developed by enriching their inviscid counterparts with a viscous character to model the irreversible deformation that develops with time. The viscoplastic strain rate is of the Duvaut-Lions type whose magnitude increases with the distance of the stress point from its projection onto the inviscid solution. With appropriate choice of an inviscid elasto-plastic soil model, one can generate quasipreconsolidation effects during creep and account for the influence of frequency on the shape and width of hysteresis loops formed during cyclic …

General Report Session 1: Static And Dynamic Soil Parameters And Constitutive Relations Of Soils, Peter M. Byrne, Li Yan

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The soil parameters that are commonly of interest in dealing with earthquake and soil dynamics problems are:

1) The maximum shear modulus G₀, or the shear wave velocity, V_s.

2) The variation of secant shear modulus with shear strain level, G/G₀ vs γ.

3) Equivalent viscous damping as a function of strain.

4) Other parameters such as, dilatometer modulus, normalized SPT or CPT value, state parameters, formation factor.

In terms of constitutive relations the following models have been used:

1) Linear elastic (total stress) - appropriate at very small strains < 10^-3%.

2) Equivalent linear …

Stiffness And Damping Parameters For Dynamic Analysis Of Retaining Walls, E. Arni Rafnsson, Shamsher Prakash

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The displacements of retaining walls developed during earthquakes have been recognized for many years. Mathematical models have been developed to simulate the behavior of retaining walls during earthquakes. The determination of the soil parameters needed for solution of the displacements has neither been adequately described nor used in a realistic analysis. In this paper theories describing spring and damping constants of rigid retaining walls, for both the base-soil and the back-fill, arc discussed along with the recommended solutions.