Review Of Available Methods For Evaluation Of Soil Sensitivity For Seismic Design,
2010
University of Western Ontario, Canada
Review Of Available Methods For Evaluation Of Soil Sensitivity For Seismic Design, Osama Abuhajar, M. Hesham El Naggar, Tim Newson
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Sensitivity describes the effect of soil disturbance/remoulding on shear strength. Cyclic stresses during seismic events may lead to varying levels of disturbance and remoulding of brittle sensitive clays. The Canadian Foundation Engineering Manual (CFEM) recommends site-specific evaluation of the seismic hazard, including site response analysis, for sites that have quick or highly sensitive clays. Different levels of soil sensitivity have been shown in different versions of CFEM and their errata. The current manual CFEM (2006) classifies clay as highly sensitive if its sensitivity is greater than 40 (classified as Class F soil). However, there is considerable variation within the literature …
Observations And Analysis Of Ground Motion And Pore Pressure At The Nees Instrumented Geotechnical Field Sites,
2010
University of California Santa Barbara, Santa Barbara, CA
Observations And Analysis Of Ground Motion And Pore Pressure At The Nees Instrumented Geotechnical Field Sites, Jamison H. Steidl, Sandra H. Seale
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The Garner Valley and Wildlife sites are producing a large data set that includes very interesting observations from earthquakes in the magnitude 4 to 7 range, with peak accelerations of ~10%g, at the threshold where nonlinear effects start to become important. In addition, hundreds of smaller earthquakes are recorded each month that provide the control data representing the linear behavior of the site. With the larger motions, we begin to see pore pressure build up on the liquefaction array at both the NEES Garner Valley Array site and at the NEES Wildlife Liquefaction Array site. We present the results of …
New Methods To Remove Arsenic From Soils,
2010
Shri Rawatpura Sarkar Institute of Technology, India
New Methods To Remove Arsenic From Soils, R. N. Khare
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
In Chhattisgarh State, arsenic content in soil is usually moderate to high. However, on some industrial sites like in Bhilai Steel Plant Bhilai, certain effluent discharges can lead to high concentrations of this chemical in the soil. After periods of rainfall and runoff, arsenic can also be found in water. In this context, Indian researchers investigated the potential of contaminations to remove arsenic from contaminated soils and waters. In addition, Electrokinetic model is developed in laboratory which has shown that, depending on soil conditions, these models are able to remove heavy metals in polluted soils by 85-90%. Overall, this research …
Coupled Cwt Spectrogram Analysis And Filtration: New Approach For Surface Wave Analysis (A Case Study On Soft Clay Site),
2010
Muhammadiyah University of Yogyakarta, Indonesia
Coupled Cwt Spectrogram Analysis And Filtration: New Approach For Surface Wave Analysis (A Case Study On Soft Clay Site), Sri Atmaja P. Rosyidi, Mohd. Raihan Taha, Zamri Chik
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Surface wave analysis consists of generation, measurement and processing of the dispersive Rayleigh waves recorded from two or more vertical transducers. However, in case of soft clay soil, the reliable dispersion curve is difficult to be produced particularly at the frequency below 20 Hz. Some noises from nature and other human-made sources may disturb the generated surface wave data. In this paper, coupled analysis of continuous wavelet transform (CWT) spectrogram analysis based on Gaussian Derivative function was used to analyze the seismic waves in different frequency and time. First analysis is time-frequency wavelet spectrogram which was employed to localize the …
Ground Improvement Under Dynamic Loading,
2010
Baugrundinstitut Franke-Meißner und Partner GmbH, Germany
Ground Improvement Under Dynamic Loading, M. Ittershagen
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
To analyze the dynamic soil-structure interaction of railway lines on soft soil experimental and numerical investigations have been carried out. The mean intention was to get information about the influence of different soil improvement layouts and further on to establish a design tool for railway lines on soft soil based on the additional results of a numerically supported parametric study. The principle part of the paper is the presentation of the experimental and numerical investigations.
Near Field Wave Transformation In Clay And Peat,
2010
Delft University of Technology, The Netherlands/ École Nationale de Polytechnique, France
Near Field Wave Transformation In Clay And Peat, Stefan Van Baars
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
A series of simple impact tests is performed, both on clay and on peat, in order to compare the current wave theory with the obtained data. The waves at the surface are measured with three 3D geophones. With this the wave propagation and the energy dissipation in three directions has been studied both for clay and peat. Since the impact produces a group of waves, only the first arrival time can easily be detected. By transferring the wave information into a 3D energy flow, also the average arrival time and the end-of-wave arrival time can be determined. The results of …
Investigation Of Shear Strain Amplitude Induced By Railroad Traffic In Soils,
2010
Engineering office GEPRO Ingenieurgesellschaft GmbH, Germany
Investigation Of Shear Strain Amplitude Induced By Railroad Traffic In Soils, Dirk Wegener, Ivo Herle
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Shear strain amplitude γ is an important quantity in dynamic soil analysis. Usually, a reduction of soil stiffness with increasing shear strain amplitude is observed in laboratory tests. An appropriate invariant of shear strain can be defined which is comparable with shear strains measured in laboratory tests. Usually, shear wave velocity cs is determined from field or laboratory tests and the particle velocity v is obtained from vibration measurements. Afterwards, the shear strain amplitude γ is often estimated from the equation γ = ν / cs, which can be derived for the case of one dimensional wave propagation. …
Propagation Of Surface Waves In An Irregular Ground Based On The Thin Layered Element And Finite Element Method,
2010
Chiba University, Japan
Propagation Of Surface Waves In An Irregular Ground Based On The Thin Layered Element And Finite Element Method, Hiroto Nakagawa, Shoichi Nakai
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The problem of wave propagation in an irregular ground is crucial when the landform is complex as in the case of Japan. This problem has been studied by a number of researchers; however, most of studies were made from the viewpoint of body wave propagation and only a few dealt with surface waves. The objective of this study is to examine Rayleigh and Love wave propagation in an irregular ground based on the combined method of thin layered element and finite element. In this paper, the following conclusions are made: 1. H/V spectra of a horizontally layered medium as well …
Stress- And Strain-Controlled Undrained Cyclic Triaxial Tests On A Fine Sand For A High-Cycle Accumulation Model,
2010
University of Karlsruhe, Germany
Stress- And Strain-Controlled Undrained Cyclic Triaxial Tests On A Fine Sand For A High-Cycle Accumulation Model, Torsten Wichtmann, Benjamin Rojas, Andrzej Niemunis, Theodor Triantafyllidis
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The paper presents a discussion of the isotropic elastic stiffness E in the high-cycle accumulation (HCA) model proposed by Niemunis et al. (2005). The model may be used to predict permanent deformations or excess pore water pressures in non-cohesive soils due to cyclic loading. The stress-dependent bulk modulus K was determined from pairs of drained and undrained cyclic triaxial tests on a fine sand with constant stress amplitude and with similar initial conditions. K was found in good agreement with an earlier study on a medium coarse sand where a correction for membrane penetration effects had to be applied. Undrained …
Vibration Analysis Of Rotating Fans Mounted On Adjacent Rectangular Foundation Blocks,
2010
URS Corporation, Seattle, WA
Vibration Analysis Of Rotating Fans Mounted On Adjacent Rectangular Foundation Blocks, C. B. Crouse, Ethan Dawson, Pedro Amaya, Prabir Sen
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Vibration analysis was conducted for large rotating fans mounted on adjacent rectangular concrete foundation blocks, 66 ft x 22 ft x 10 ft depth, with the adjacent long sides 10 ft apart. The blocks were embedded in medium dense sands and gravels with a variable shear-wave velocity profile. The purpose of the analysis was to determine whether (1) the dynamic interaction of the blocks through the surrounding soil would cause unacceptable vibratory response of the fans, and (2) the foundation stiffness criterion set by the vendor was satisfied. Solutions were obtained using the 3-D dynamic version of the FLAC computer …
Viscous Damping For Time Domain Finite Element Analysis,
2010
University of Colorado Denver, Denver, CO
Viscous Damping For Time Domain Finite Element Analysis, Nien-Yin Chang, Hien Manh Nghiem
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Earthquake waves propagate mainly in rock mass from hypocenter to the bedrock directly underneath a monitoring station. Then, it propagates as shear waves from the bedrock to a geophone, where the surface motion is measured. For a deposit with uniform soil layers of horizontal interfaces, one-dimensional finite element analysis can be performed to analyze the dynamic responses of a horizontal soil deposit. In an ideal dynamic soil-structure interaction analysis, seismic waves are propagated from the bedrock through soils and foundations, and then to structure. Thus, it is necessary to obtain the bedrock motion from a measured surface motion registered in …
A Validation Study Of A Seismically Induced Ground Strain Model Using Strong Motion Array Data,
2010
University of California, Los Angeles, CA
A Validation Study Of A Seismically Induced Ground Strain Model Using Strong Motion Array Data, Timothy D. Ancheta, Jonathan P. Stewart
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
This study concerns ground strains that result from spatially variable ground motions unrelated to ground failure. Prior empirical work shows a dependence of peak ground strain (PGS) on peak ground displacement (PGD) but is applicable only for weak motions (PGD < 10 cm). Prior semi-empirical work, in which strains were evaluated from simulated ground motions that preserve the coherency, Fourier amplitude variability and wave passage observed in array recordings, found a similar dependence of PGS on PGD but also a significant dependence on separation distance of observation points. Here we describe a procedure to calculate PGS between pairs of stations in an array to test the separation dependence of PGS. The Lotung LSST array was selected due to its closely spaced stations (6 to 85 m) and large number of recordings. The PGS estimated from station pairs from 11 events illustrate that the distance dependence of PGS is statistically significant, with PGS increasing as separation distance decreases.
Development Of Seismic Safety During Pre- And Co-Seismic Periods,
2010
Consulting Seismologist, India
Development Of Seismic Safety During Pre- And Co-Seismic Periods, Arun Bapat
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Since the year 2000 a large number of earthquakes have taken place. But despite advances in disaster management and seismology, till now it has not been possible to save a single life during earthquake. Issue of forewarning based on reliable seismic precursors has not been considered. Large magnitude earthquakes in India, Indonesia, Pakistan, Iran, China, Italy, and Peru etc were unexpected jolts to the disaster managers. Practically each earthquake has taken heavy death toll in India, Pakistan, Iran, and China etc. If some precursory warning were issued, it would help in saving at least some lives. The issue of earthquake …
Effect Of Topographical Irregularities On Seismic Earthquake Response Of Construction Site – 2d Numerical Analysis Of Trapezoidal Valley Under Real Motion,
2010
Islamic Azad University, Iran
Effect Of Topographical Irregularities On Seismic Earthquake Response Of Construction Site – 2d Numerical Analysis Of Trapezoidal Valley Under Real Motion, Hamed Khodadadi Tirkolaei, Morteza Jiryaei Sharahi
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Documented observation of destruction distribution after seismic events suggest to topography effects on earthquake intensity. But there exist very few –if any- well documented case studies where topography effects are illustrated for strong ground motion. This is due to complex nature of seismic scattered wave by topographical structures to medium. Although some empirical correlations, obtained from statistical analyses, were proposed in different studies to consider this issue, but these correlations also may not be applicable in general or may be overestimation of what happen in reality. These difficulties and disadvantages can only be solved accurately, economically and under realistic conditions …
Evaluation Of Seismic Response Of A Site Class F Site Using Equivalent Linear And Nonlinear Computer Codes,
2010
GeoEngineers, Inc., Redmond, WA
Evaluation Of Seismic Response Of A Site Class F Site Using Equivalent Linear And Nonlinear Computer Codes, King H. Chin, Braydan Duree, Whitney Trent, Gustavo Ordonez
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Evaluation of seismic site response and development of site-specific surface response spectra has evolved in recent years through the use of both equivalent linear (EQL) and nonlinear (NL) computer codes. Before the nonlinear computer codes become popular among practitioners, equivalent linear site response analysis programs were used to develop site-specific design spectra for both soft and stiff sites. Nonlinear site response analysis is now used more routinely for projects planned on Site Class F sites. This paper presents the results of seismic response analyses completed for a Site Class F site at Grays Harbor, Washington. Both the equivalent linear (SHAKE2000) …
Example For Risk Estimation Of Fault Appearance Under The Place Of Designed Skyscraper In Sofia,
2010
University of Transport, Bulgaria
Example For Risk Estimation Of Fault Appearance Under The Place Of Designed Skyscraper In Sofia, Chavdar V. Kolev, Martina G. Perikliyska
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
There was an interesting discussion during the designing stage of one of the future skyscrapers in Sofia – is the soil basement reliable enough if it is true the hypotheses for a fold under the construction place? The substantial geotechnical report doesn’t give answers to this question but the geological profiles suggest to us about an appearance of fold. Topographic and historical specifics of the area are supporting the same unsuitable idea. The additional geophysics investigations clearly establish a lack of fold displacements under the place during the Quaternary period. The zone has high seism and an individual seismic ratio …
Ground Motion Occurrence Rates For Scenario Spectra,
2010
University of California Davis, Davis, CA
Ground Motion Occurrence Rates For Scenario Spectra, Norman Abrahamson, A. Anil Yunatci
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
It is common practice for probabilistic seismic hazard analysis (PSHA) to use the uniform hazard spectra (UHS) to describe the ground motion. A short-coming of UHS is that it represents an envelope of many different earthquakes that control the hazard at different spectral periods. As an alternative, the UHS can be broken into a suite was developed by Baker and Cornell (2006), in which conditional mean spectra (CMS) are developed that represent realistic earthquake scenarios given a specified spectral acceleration at a single period. Using only the CMS as scenarios is too restrictive and does not provide enough scenarios to …
Selection Of An Appropriate AMax For Liquefaction Analyses From One-Dimensional Site Response Analyses,
2010
The Shaw Group Inc., Stoughton, MA
Selection Of An Appropriate AMax For Liquefaction Analyses From One-Dimensional Site Response Analyses, Rabia Z. Sarica
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
This paper is an attempt to clarify a possible confusion regarding which maximum ground acceleration (amax) should be used when performing a site-specific liquefaction analysis. Usually, one-dimensional free-field site response analysis is performed to estimate amax at the foundation elevation and the strain-compatible soil parameters within the soil profile. From the soil-structure interaction (SSI) analysis perspective, this calculation is repeated for the best-estimate, lower-bound, and upper-bound soil profiles. For this, the shear moduli are adjusted using a coefficient of variation (cv) to account for the spatial variation in the soil properties and the uncertainties in …
The Levelled-Energy Multifrequencial Analysis For Deriving Dynamic Equivalent Signals (Lema_Des): Application For An Earthquake Scenario,
2010
University Paris East, Laboratoire Central des Pontes et Chaussées (LCPC), France
The Levelled-Energy Multifrequencial Analysis For Deriving Dynamic Equivalent Signals (Lema_Des): Application For An Earthquake Scenario, Luca Lenti, Salvatore Martino
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
An equivalent acceleration signal can be regarded as an acceleration time history, inferred from a reference acceleration record which can be defined in different ways on the basis of different equivalence criteria such as: 1) kinematic characteristics of the signal; 2) Fourier spectrum amplitude; 3) Fourier spectrum phase values; 4) response spectrum; 5) energy. The equivalent signals may be employed in technical-scientific applications, when common theoretical approaches or instrumental devices can hardly manage the whole complexity of the actual phenomena to be investigated. As their definition suggests, equivalent signals are full-fledged analogue tools for modelling natural processes (real prototypes) as …
Variability In Earthen Levee Seismic Response Due To Time-History Selection,
2010
The University of Michigan, Ann Arbor, MI
Variability In Earthen Levee Seismic Response Due To Time-History Selection, Adda Athanasopoulos-Zekkos
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
In seismic slope stability analyses the single most important input parameter is the ground motion. Time-history selection is a challenging engineering problem since the variability in ground motion characterization is in part due to the complexity of the mechanisms that result in a seismic event taking place and the path and soil conditions from the origin of the seismic event to the location of interest. In this study, the effect of key ground motion parameters to the dynamic response of earthen levees is investigated. Specifically, the effect on the induced cyclic shear stress ratio (CSR) and/or seismically induced Newmark-type, permanent …
