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Articles 2341 - 2370 of 7869

Full-Text Articles in Civil and Environmental Engineering

The Universal Void Ratio Function For Small Strain Shear Modulus, Man T. Bui, C. R. I. Clayton, Jeffrey A. Priest May 2010

The Universal Void Ratio Function For Small Strain Shear Modulus, Man T. Bui, C. R. I. Clayton, Jeffrey A. Priest

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

Small strain shear modulus, Gmax, is a key parameter representing the small strain response of soils under seismic load. It is also an important parameter in design of foundations where only small deformation takes place. It is recognised that Gmax is significantly influenced by void ratio. The influence of void ratio on Gmax of a soil has been taken into account by using an empirical void ratio function, F(e), and various forms of F(e) have been proposed. However, each F(e) can only be applied for a given soil within a limited void ratio range. There was …

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Multi Channel Analysis Of Surface Wave (Masw) Testing For Dynamic Site Characterization Of Delhi Region, D. Neelima Satyam, K. S. Rao May 2010

Multi Channel Analysis Of Surface Wave (Masw) Testing For Dynamic Site Characterization Of Delhi Region, D. Neelima Satyam, K. S. Rao

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

After the Bhuj earthquake the national capital region of Delhi attracted major attention of several scientific studies in the recent times. Since Delhi falls in zone IV (IS 1893: 2002) with high seismic activity, there is a great need for site characterization and seismic hazard mapping of the area. Multi Channel Analysis of Surface Wave (MASW) tests were done in Delhi at 118 sites in predefined grids of 2kmX3km each. Shear-wave velocity, VS, is an important parameter for evaluating dynamic behavior of soil. This test carried outdone using 48 channel digital seismograph with 4.5 Hz geophones. Data was analyzed using …

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Comparison Of Dynamic Soil Modelling Using Scpt, Sdmt And Sasw, Kayhan Aykin, Onder Akcakal, H. Turan Durgunoglu, Ozer Akbal May 2010

Comparison Of Dynamic Soil Modelling Using Scpt, Sdmt And Sasw, Kayhan Aykin, Onder Akcakal, H. Turan Durgunoglu, Ozer Akbal

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

A site investigation campaign using cone penetration test (CPT), dilatometer test (DMT) are carried on alluvial deposits at a site located at Gemlik, Turkey towards the design of a newly planned hot reverse mill structure within the existing Borçelik steel factory. Site is located at the south of North Anatolian Fault that is sheared during 1999 Kocaeli Earthquake. In addition, the site is under the influence zone of another fault line going through the Gemlik Bay. Therefore, prediction of the behaviour of saturated alluvial deposits under a major expected design earthquake of the planned structures is the prime importance in …

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Reproduction, By Means Of True Scale Testing, Of The Effects Caused On A Track By High Speed Railway Traffic, Javier Moreno Robles, Vicente Cuéllar Mirasol May 2010

Reproduction, By Means Of True Scale Testing, Of The Effects Caused On A Track By High Speed Railway Traffic, Javier Moreno Robles, Vicente Cuéllar Mirasol

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

Nowadays, the social importance of the railway transportation is accepted without any doubt, and the levels of comfort and operation quality associated to railways are continuously increasing. The travel times that could be considered allowable in the past century are now obsolete and in order to reduce time “losses”, traffic speeds larger than 300 km/h are being asked for. In order to analyse properly the behaviour of the different layers that make up the railway track structure, the Centro de Estudios y Experimentación de Obras Públicas (CEDEX) of the Ministerio de Fomento, Spain, has built a large facility (5 x …

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Correlation Between Low Strain Shear Modulus And Standard Penetration Test ‘N’ Values, P. Anbazhagan, T. G. Sitharam, P. Aditya May 2010

Correlation Between Low Strain Shear Modulus And Standard Penetration Test ‘N’ Values, P. Anbazhagan, T. G. Sitharam, P. Aditya

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

In this study an attempt has been made to develop correlation between standard penetration test (SPT) N values and low strain shear modulus (Gmax). The field experiments of Multichannel Analysis of Surface Wave (MASW) are carried out at 38 locations close to boreholes having Standard Penetration Test N values and in-situ density. These experimental data were generated and used for seismic microzonation of Bangalore, India. In-situ densities of subsurface layers were obtained from undisturbed soil samples collected from the boreholes. Shear wave velocity (Vs) profile with depth were obtained for the same locations or close to the boreholes …

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Centrifuge Modeling Of The Influence Of Pre-Existing Fractures In Multilayered Soils On Ground Deformations, P. Hu, Y. H. Ding, Q. P. Cai, G. Y. Luo, C. W. W. Ng, Y. J. Hou May 2010

Centrifuge Modeling Of The Influence Of Pre-Existing Fractures In Multilayered Soils On Ground Deformations, P. Hu, Y. H. Ding, Q. P. Cai, G. Y. Luo, C. W. W. Ng, Y. J. Hou

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

Fault rupture propagation in free fields lays the ground for an understanding of bedrock-soil-structure interactions. Propagation behaviors in dry soil have long been investigated. Localized shear bands have been identified to be the obvious source of failure in dry soils at depth. In addition, numerous subsurface fractures have been found in the field. However, the influence of subsurface fractures in the soil on future seismic faults has received little attention, especially in complex soils. In this study, three centrifuge tests were conducted to investigate the influence of pre-existing fractures on ground deformations in three multilayered soils: three-layered, five-layered and nine-layered …

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Increasing Lateral Capacity Of Helical Piles With Lateral Restraint Devices, John L. Maier, Ali M. Oskoorouchi May 2010

Increasing Lateral Capacity Of Helical Piles With Lateral Restraint Devices, John L. Maier, Ali M. Oskoorouchi

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

Deflection analysis of piles under lateral live loads in various soil conditions is presented herein. Field testing of lateral capacity was conducted at four test sites in California and Nevada, where weak surface soil provides insufficient lateral capacity for helical piles. In these areas of weak surface soil, as defined by field or laboratory testing, the most feasible solution for a foundation system may be the implementation of a deep foundation system such as a pier and grade beam or helical pile (HP) foundation system. Helical pile diameters that normally range from 1-1/2 to 4 inches provide minimal support when …

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P-Wave Reflection Imaging Of Laboratory Soil Models, Joseph Coe, Scott J. Brandenberg May 2010

P-Wave Reflection Imaging Of Laboratory Soil Models, Joseph Coe, Scott J. Brandenberg

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

An ultrasonic p-wave reflection imaging system is used to non-invasively image submerged soil models with embedded anomalies and complex geometric layer contacts. The ultrasonic transducers emit compressive waves into water that subsequently transmit into the underlying soil, and measurements of the reflections are used to construct the images. Properties of the transducers and data acquisition hardware and software are explained. A soil model consisting of embedded high- and low-impedance anomalies, dipping soil layer contacts, and an undulating concrete base layer was imaged using 500 kHz transducers. The geometric features of the model are clearly visible in the images.

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Passive Earth Pressure Force-Displacement Relationships, Patrick Wilson, Ahmed Elgamal May 2010

Passive Earth Pressure Force-Displacement Relationships, Patrick Wilson, Ahmed Elgamal

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

During a strong earthquake, passive earth pressure can provide resistance to excessive displacements along bridge abutments and pile caps. To account for this contribution, the force-displacement relationship is required, in addition to the peak resistance value. Experiments were performed at the University of California, San Diego to record the passive earth pressure force-displacement relationship behind a 1.7 meter tall vertical wall section. The experimental configuration of the soil container and wall system is described first. Backfill consisting of dense well-graded silty sand was placed in the soil container which measured 5.6 meters long, 2.9 meters wide and 2.15 meters deep. …

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Experiences In Pumice Soil Characterization By Surface Wave Analysis, Salvador Lazcano May 2010

Experiences In Pumice Soil Characterization By Surface Wave Analysis, Salvador Lazcano

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

Guadalajara, México, is a large city located mainly over a thick deposit (up 100 m) of pumice, in a seismic zone. Then, besides the stiffness of pumice soils, it is important to predict their behavior under seismic movements. Pumice soils are so crushable that SPT or CPT does not adequately characterize them. As a complement or alternative to SPT, CPT and other field testing, in recent years there has been a gradual increment in the use of surface wave analysis for soil characterization, by measuring shear wave velocity (VS). ReMi is one of the surface wave analysis methods …

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Field Measurement Of Dynamic Soil Properties Of Tropical Meta-Sediment Residual Soils, Zamri Chik, Susy K. Ariestianty, Sri Atmaja P. Rosyidi, Khairul Anuar Mohd. Nayan, Mohd. Raihan Taha May 2010

Field Measurement Of Dynamic Soil Properties Of Tropical Meta-Sediment Residual Soils, Zamri Chik, Susy K. Ariestianty, Sri Atmaja P. Rosyidi, Khairul Anuar Mohd. Nayan, Mohd. Raihan Taha

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

The study area which was located in Peninsular Malaysia comprised of residual meta-sedimentary soil derived Kenny Hill Formation. The dynamic soil properties of tropical meta-sediment residual soils were measured using non-destructive seismic method known as Multi-channel Analysis of Surface Wave (MASW) method. Twenty four geophones were located on ground in order to measure surface wave propagation. By inversion of dispersion curve, the shear wave velocity profile could be calculated and obtained. For most site investigations, other conventional method of field testing had been conducted such as drilling and Standard Penetration Test (SPT). This paper, however, attempts to obtain the comprehensively …

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Innovative Triaxial/Resonant Column Equipment, Diego Carlo Federico Lo Presti, Nunziante Squeglia, Oronzo Pallara May 2010

Innovative Triaxial/Resonant Column Equipment, Diego Carlo Federico Lo Presti, Nunziante Squeglia, Oronzo Pallara

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

The present paper describes a new triaxial apparatus which allows the measurement of low strain stiffness by means of both bender elements and resonant column test. In a previous paper Squeglia et al. (2009) described the innovative use of bender elements as receivers for the measurement of shear wave velocity. The proposed technique is synthetically described with the further development of apparatus which allow to perform resonant column test during a triaxial test. Since the apparatus has not been designed as a resonant column device, some critical points have been dealt with. Some tests have been dedicated to solve the …

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Review Of Available Methods For Evaluation Of Soil Sensitivity For Seismic Design, Osama Abuhajar, M. Hesham El Naggar, Tim Newson May 2010

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 …

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Observations And Analysis Of Ground Motion And Pore Pressure At The Nees Instrumented Geotechnical Field Sites, Jamison H. Steidl, Sandra H. Seale May 2010

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 …

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New Methods To Remove Arsenic From Soils, R. N. Khare May 2010

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 …

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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 May 2010

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 …

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Ground Improvement Under Dynamic Loading, M. Ittershagen May 2010

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.

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Near Field Wave Transformation In Clay And Peat, Stefan Van Baars May 2010

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 …

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Investigation Of Shear Strain Amplitude Induced By Railroad Traffic In Soils, Dirk Wegener, Ivo Herle May 2010

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. …

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Propagation Of Surface Waves In An Irregular Ground Based On The Thin Layered Element And Finite Element Method, Hiroto Nakagawa, Shoichi Nakai May 2010

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 …

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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 May 2010

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 …

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Vibration Analysis Of Rotating Fans Mounted On Adjacent Rectangular Foundation Blocks, C. B. Crouse, Ethan Dawson, Pedro Amaya, Prabir Sen May 2010

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 …

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Viscous Damping For Time Domain Finite Element Analysis, Nien-Yin Chang, Hien Manh Nghiem May 2010

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 …

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A Validation Study Of A Seismically Induced Ground Strain Model Using Strong Motion Array Data, Timothy D. Ancheta, Jonathan P. Stewart May 2010

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.

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Development Of Seismic Safety During Pre- And Co-Seismic Periods, Arun Bapat May 2010

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 …

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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 May 2010

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 …

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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 May 2010

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) …

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Example For Risk Estimation Of Fault Appearance Under The Place Of Designed Skyscraper In Sofia, Chavdar V. Kolev, Martina G. Perikliyska May 2010

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 …

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Ground Motion Occurrence Rates For Scenario Spectra, Norman Abrahamson, A. Anil Yunatci May 2010

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 …

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Selection Of An Appropriate AMax For Liquefaction Analyses From One-Dimensional Site Response Analyses, Rabia Z. Sarica May 2010

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 …

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