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Articles 2641 - 2670 of 4583

Full-Text Articles in Engineering

Seismic Analysis Of Pile Foundations Damaged In The January 17, 1995 South-Hyogo Earthquake By Using The Seismic Deformation Method, Xiu Luo, Yoshitaka Murono Mar 2001

Seismic Analysis Of Pile Foundations Damaged In The January 17, 1995 South-Hyogo Earthquake By Using The Seismic Deformation Method, Xiu Luo, Yoshitaka Murono

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

With respect to the South-Hyogo Earthquake of January 17, 1995, a lot of research results have been published including many studies on the damage to pile foundations resulting from liquefaction as well as consequent lateral flow of surface ground (Mori et al, 2000 and Horikoshi et al, 2000). However, reports concerning seismic analyses of foundations damaged by non-liquefaction causes, such as ground shaking, are still rare. Actually, studies on non-liquefaction damage are also important because this kind of damage may occur in a more extensive scope than the liquefaction damage may. This paper summarizes a seismic analysis of a pile …

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Nonlinear Response Of Underground Duct Structures With Due Attention To Seismic Input Ground Motions, Hirokazu Takemiya, Jorge Shimabuku, Yoshifumi Katayama, Kentaro Kishida, Satoru Furukawa Mar 2001

Nonlinear Response Of Underground Duct Structures With Due Attention To Seismic Input Ground Motions, Hirokazu Takemiya, Jorge Shimabuku, Yoshifumi Katayama, Kentaro Kishida, Satoru Furukawa

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

Under destructive earthquake motions, structures behave heavily in nonlinear manner that is quite different from the linear response computation. The underground structures such as tunnels, ducts are susceptible to the ground motions so that the nonlinear interaction analysis should be performed for the reliable design. In case of irregular soil profile, due to the surface wave generation, the vertical motions come out to a less negligible extent compared to the horizontal motions. The present paper has concerned with such nonlinear response evaluation of a duct structure under strong motions. The effect of the transient characteristics in the inland type and …

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Pile Response Characteristics Of Liquefied Soil Layers In Shaking Table Tests Of A Large Scale Laminar Shear Box, Kaeko Yahata, Yasutsugu Suzuki, Hideki Funahara, Mutsuhiro Yoshizawa, Shuji Tamura, Kohji Tokimatsu Mar 2001

Pile Response Characteristics Of Liquefied Soil Layers In Shaking Table Tests Of A Large Scale Laminar Shear Box, Kaeko Yahata, Yasutsugu Suzuki, Hideki Funahara, Mutsuhiro Yoshizawa, Shuji Tamura, Kohji Tokimatsu

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

To better understand the causes of pile damages during earthquakes such as Hyogoken-Nanbu Earthquake, shaking table tests of soil-pile-structure interaction models were done using a large scale laminar shear box. Because the pile response is affected by both the ground motion and the structure's inertial forces, three models were test & a soil-pile model and two soil-pile-structure models. For the latter models, superstructures with long and short natural periods were tested separately. Through comparisons among the three cases, the influences on the pile response due to the inertial force of the superstructure for the long and short natural periods were …

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Seismic Response Assessment Of Underground Structure Cross-Sections Using Response Spectra, Rui Carrilho Gomes, Carlos Sousa Oliveira, António Gomes Correia Mar 2001

Seismic Response Assessment Of Underground Structure Cross-Sections Using Response Spectra, Rui Carrilho Gomes, Carlos Sousa Oliveira, António Gomes Correia

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

A modelling technique of the cross-sections of underground structures based on the combination of modal shapes by response spectra is developed and calibrated according to the vertically propagating shear-wave model. Using the developed technique, the influence of several parameters in the flexibility index (ground-structure relative stiffness) were studied. To point out a few practical implications and simplifications introduced in the model, essentially related to the material behaviour adopted, four cases were studied in detail. To cover the lack of compatibility between the damping of the response spectrum, the ground stiffness and the strain level, more analyses with compatible properties were …

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Simplified Methods For The Dynamic Analysis Of Single Pile In Layered Soils, Roberto Cairo, Enrico Conte, Giovanni Dente Mar 2001

Simplified Methods For The Dynamic Analysis Of Single Pile In Layered Soils, Roberto Cairo, Enrico Conte, Giovanni Dente

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

In this paper, two simplified methods are used to calculate the impedance function of an axially loaded pile embedded in layered soils. The methods are: a semi-analytical procedure which uses the discrete layer stiffness matrices derived by Kausel and Roesset (1981), and the cone model which was developed by Wolf et al. (1992). A number of comparisons with more rigorous solutions are shown in order to assess the accuracy of the methods used.

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Structure Soil Structure Interaction Effects: Seismic Analysis Of Safety Related Collocated Concrete Structures, Jayaprakash A. Amin, Jagdish J. Bhat, Jagadish R. Joshi Mar 2001

Structure Soil Structure Interaction Effects: Seismic Analysis Of Safety Related Collocated Concrete Structures, Jayaprakash A. Amin, Jagdish J. Bhat, Jagadish R. Joshi

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

The Process, Purification and Stack Buildings are collocated safety related concrete shear wall structures with plan dimensions in excess of 100 feet. An important aspect of their seismic analysis was the determination of structure soil structure interaction (SSSI) effects, if any. The SSSI analysis of the Process Building, with one other building at a time, was performed with the SASSI computer code for up to 50 frequencies. Each combined model had about 1500 interaction nodes. Results of the SSSI analysis were compared with those from soil structure interaction (SSI) analysis of the individual buildings, done with ABAQUS and SASSI codes, …

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Back-Calculated P-Y Relation Of Liquefied Soils From Large Shaking Table Tests, Kohji Tokimatsu, Hiroko Suzuki, Yasutusu Suzuki Mar 2001

Back-Calculated P-Y Relation Of Liquefied Soils From Large Shaking Table Tests, Kohji Tokimatsu, Hiroko Suzuki, Yasutusu Suzuki

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

Time histories of the p-y behavior during soil liquefaction, defined as the relation between subgrade reaction and relative displacement between pile and soil, are back-calculated based on shaking table tests using a large-scale laminar box. The results show that, if the pile pushes the soil, the subgrade reaction is correlated with the relative displacement between pile and soil. In contrast, if the soil liquefies and pushes the pile, the subgrade reaction becomes correlated with the relative velocity between pile and soil. The p-y curve of loose sand shows stress-softening behavior after liquefaction, while the p-y curve of medium dense to …

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Methodology And Final Results Of The Medellin Seismic Instrumentation And Microzonation Project, Gloria Estrada, Manuel Villarraga Mar 2001

Methodology And Final Results Of The Medellin Seismic Instrumentation And Microzonation Project, Gloria Estrada, Manuel Villarraga

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

Medellin is an important industrial city of Colombia, which is the capital of Antioquia province (department) and it is located in the northwest of this country. It has a very high population density about 2,000,000 people and an area of just 100 km2. Its location makes it very susceptible to suffer earthquakes and its great topographical and geological diversity stand out the importance of local effects associated to earthquakes. These reasons led to carry out the Medellin Seismic Instrumentation and Microzonation Study, which main purpose was to develop and propose new provisions for designing and constructing new buildings …

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Radius-Managing Urban Earthquake Risk In Developing Countries, Carlos Villacís, Cynthia Cardona Mar 2001

Radius-Managing Urban Earthquake Risk In Developing Countries, Carlos Villacís, Cynthia Cardona

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

The IDNDR launched the RADIUS initiative to reduce the effects of seismic disasters in urban areas, particularly in developing countries. This initiative had two concrete objectives: 1) development of seismic damage scenarios and earthquake risk management plans for nine selected cities worldwide, and 2) development of practical tools for urban seismic risk management using the results of the case studies. Additionally, the project had three specific objectives for each of the selected cities: to 1) raise awareness, both locally and internationally, of the city's seismic risk, 2) incorporate all the sectors of the community in the risk management activities, and …

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Numerical Study On 3-Dimensional Behavior Of A Damaged Pile Foundation During The 1995 Hyogo-Ken Nanbu Earthquake, Ryosuke Uzuoka, Tetsuo Kubo, Atsushi Yashima, Feng Zhang Mar 2001

Numerical Study On 3-Dimensional Behavior Of A Damaged Pile Foundation During The 1995 Hyogo-Ken Nanbu Earthquake, Ryosuke Uzuoka, Tetsuo Kubo, Atsushi Yashima, Feng Zhang

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

The purpose of this study is to investigate the process of the damage to a pile foundation located on a reclaimed land during the 1995 Hyogo-ken Nanbu earthquake. A 3-dimensional effective stress analysis using a soil-pile-building model was conducted on a damaged building. The five stories building tilted in a northeast direction because of serious damages to the pile foundations. Sand boils and ground settlements due to liquefaction were observed around the building. The simulated results showed that the reclaimed fill layer liquefied during the earthquake, and horizontal displacements of several tens centimeters occurred at the ground surface. The spatial …

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Soil-Pile Interaction Analysis Using Fe-Be Coupling In Frequency Domain, Moon Kyum Kim, Yun Mook Lim, Min Kyu Kim, Seok Ho Cho Mar 2001

Soil-Pile Interaction Analysis Using Fe-Be Coupling In Frequency Domain, Moon Kyum Kim, Yun Mook Lim, Min Kyu Kim, Seok Ho Cho

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

In this study, a numerical method for soil-pile interaction problems in multi-layered half-plane is developed in frequency domain using FE-BE coupling technique. The soil-pile interaction system is divided into two parts, so-called near field and far field. In the near field, beam elements are used for modeling pile and plane-strain finite elements for surrounding soil media. Also, a superstructure is considered as a lumped mass on a pile. In the far field, layered soil media is modeled by boundary element formulation using the dynamic fundamental solution. Then, these two fields are assembled using FE-BE coupling technique. This coupled numerical method …

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Effect Of The Non-Linear Behavior Of Pile Material On The Response Of Laterally Loaded Piles, Mohamed Ashour, Gary Norris, Anooshirvan Shamsabadi Mar 2001

Effect Of The Non-Linear Behavior Of Pile Material On The Response Of Laterally Loaded Piles, Mohamed Ashour, Gary Norris, Anooshirvan Shamsabadi

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

The main purpose of this study is to assess the lateral response of piles/shafts and the p-y curves for different soil-pile combinations while introducing the effect of the moment-curvature (M - Φ) relationship of the pile into the soil-pile interaction. Therefore, the equilibrium among soil reaction, pile deflection pattern, pile-head load, and flexural stiffness distribution should be satisfied at any level of loading. The influence of the nonlinear behavior of the pile/drilled shaft material on the nature of the associated p-y curve is presented through strain wedge (SW) model analysis. The SW model allows the assessment of the (soil-pile) modulus …

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Granular Material Behaviour Under Dynamic Excitation, Rocco Wagner, Konstantin Meskouris Mar 2001

Granular Material Behaviour Under Dynamic Excitation, Rocco Wagner, Konstantin Meskouris

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

This paper deals with the investigation of bulk material filled silos under seismic excitation. The described numerical model for a silo consists of three components, namely the granular material, an interface element between the granular material and the silo wall and the silo itself. The bulk material behaviour is described in four different ways: by the classical hypoplasticity theory, by two special versions of it which use time history functions and finally by the intergranular strain approach. The dynamic behaviour as described by these four different material laws is presented, as well as comparisons of the numerical results with experimental …

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Lateral Flow Deformation Evaluation Of Ground-Structure System Under Various Cyclic Loading Conditions, Masahiro Miyaura, Seiichi Miura, Shima Kawamura, Shoji Yokohama Mar 2001

Lateral Flow Deformation Evaluation Of Ground-Structure System Under Various Cyclic Loading Conditions, Masahiro Miyaura, Seiichi Miura, Shima Kawamura, Shoji Yokohama

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

In order to clarify the mechanical behaviors of sand grounds induced by various loadings including sea wave forces, traffic vibrations and earthquake etc., a series of model tests were carried out on model structure-ground system by using, the two-dimensional plane strain soil box apparatus. It was found that; (1) the lateral flow behavior of ground depends strongly on settlement performance of a structure, (2) the bearing capacity of ground may be evaluated by a failure envelope which is depicted in M-V-H plane irrespective of the difference in loading conditions and (3) the stability of sand ground-structure system can be assessed …

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Foundation-Soil-Inclusion Interaction Modelling For Rion-Antirion Bridge Seismic Analysis, Dan Yang, Ricardo Dobry, Ralph B. Peck Mar 2001

Foundation-Soil-Inclusion Interaction Modelling For Rion-Antirion Bridge Seismic Analysis, Dan Yang, Ricardo Dobry, Ralph B. Peck

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

The Rion-Antirion Bridge in Greece will span a total length of 352 1 m, which includes a five span cable-stayed bridge 2252m in length and two approach viaducts. Upon completion in 2004, the bridge will be the longest cable-stayed bridge in the world. The main factors affecting the foundation design involve high seismicity, poor in-situ soil conditions, deep sea water (65m) and high ship impact force. These factors called for an innovative foundation design for each of the 90m diameter piers by the foundation designer, Geodynamique et Structure (GDS) from France. The proposed design consists of vertical open-ended steel cylinders …

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Prediction Of Lateral Dynamic Response Of Single Piles Embedded In Fine Soils, Shamsher Prakash, Houda Jadi Mar 2001

Prediction Of Lateral Dynamic Response Of Single Piles Embedded In Fine Soils, Shamsher Prakash, Houda Jadi

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

The lateral dynamic response of a single pile predicted by analytical models often yields higher natural frequencies and lower resonant amplitudes than those determined in field tests. This has been related to overestimated soil’s shear modulus and radiation damping used in the calculations of the response. The objective of this study was to determine a simple method to improve the theoretical predictions, primarily those of piles embedded in clay or fine silty sands. Accordingly, reduction factors to the soil’s shear modulus and radiation damping were proposed. These factors were related to the shear strain at predicted peak amplitudes.

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Seismic Risk And Site Response Analysis For City Of Bandung-Indonesia, I. Wayan Sengara, Yulman Munaf, Aswandi, I Gede Mahardika Susila Mar 2001

Seismic Risk And Site Response Analysis For City Of Bandung-Indonesia, I. Wayan Sengara, Yulman Munaf, Aswandi, I Gede Mahardika Susila

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

Bandung is considered as a relatively earthquake prone region. Seismic risk analysis considering subduction zone and surrounding active strike-slip faults in the area was performed. Crouse and Joyner & Boore attenuation functions were adopted for the subduction and strike-slip faults, respectively. The analysis was performed employing total probability theorem using EQRISK program with modification on the attenuation functions. The analysis indicated that peak base-rock acceleration is 147 gal and 200 gal for 200 and 500 years return period, respectively. Local site effects were considered by performing site response analyses in the form of wave propagation analysis from base-rock to ground …

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Geotechnical Data Base For The City Of Zagreb And Its Application In Site Response Analyses, Predrag Kvasnička, Leo Matešić Mar 2001

Geotechnical Data Base For The City Of Zagreb And Its Application In Site Response Analyses, Predrag Kvasnička, Leo Matešić

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

Geotechnical reports, filed in the city archives, are the source of data among which relevant properties for mechanical soil behavior and site response analyses are recognized and digitised. The properties are digitised in an organized manner into the GIS related software called “Techbase”, developed by “MINEsoft“, Lakewood, Colorado. The basic element of the database is a boring log containing distributions of soil properties with depth. More than 150 boring logs, located in the western part of Zagreb, are digitized and their coordinates mapped using “Techbase”. The aim of this paper is not only to describe the collection of the geotechnical …

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Study On Seismic Retrofit Planning Method For Seweage Treatment Plants On The Basis Of Seismic Risk Management, Akira Yuasa, Tsuneo Ohsumi, Kenichi Yamamoto, Tetsutaro Kawakami Mar 2001

Study On Seismic Retrofit Planning Method For Seweage Treatment Plants On The Basis Of Seismic Risk Management, Akira Yuasa, Tsuneo Ohsumi, Kenichi Yamamoto, Tetsutaro Kawakami

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

Japanese sewerage has more than 100 years of history, and many facilities have passed their durable years. For the sake of economy, life lengthening of the equipment and facilities is required. Rational life extension of the equipment and facilities calls for aseismic reinforcement of structures with damage risks considered. Based on this, the author et al. suggested a method that will help planning rational aseismic reinforcement for sewage treatment plants. This method quantitatively evaluates the relationship between the earthquake risk and aseismic reinforcement cost by introducing the concept of risk management. In this study, availability of this method also has …

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Site Response Of Organic Soils, Rajendram Arulnathan, R. W. Boulanger, I. M. Idriss Mar 2001

Site Response Of Organic Soils, Rajendram Arulnathan, R. W. Boulanger, I. M. Idriss

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

A primary source of uncertainty in any evaluation of the seismic stability of the Sacramento-San Joaquin Delta levee system is the site response characteristics of the shallow organic soils that commonly underlay the levees. This paper provides an overview of recent research on the site response characteristics of organic soils using centrifuge and numerical modeling. The centrifuge modeling effort included the development of techniques to measure the shear wave velocity profile for a centrifuge model while in-flight. One-dimensional site response analyses using an equivalent linear procedure were performed with the measured shear wave velocity profiles and the modulus reduction and …

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Global Methodology For Soil Behavior Identification And Its Application To The Study Of Site Effects, A. Modaressi, F. López-Caballero Mar 2001

Global Methodology For Soil Behavior Identification And Its Application To The Study Of Site Effects, A. Modaressi, F. López-Caballero

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

Though it is now admitted that non-linear modeling of soil behavior is necessary to represent some important aspects of the soil response under strong ground motion (for example, irreversible settlements and pore-pressure build-up), the elastoplastic models are not yet used in the everyday design processes. One of the obstacles is the difficulty to identify the models’ parameters. A methodology to identify the soil mechanical parameters is presented and applied to an elastoplastic model. The strategy is based on the use of minimum physical and easily measurable parameters. The key parameter necessary for characterizing the clay is its Liquidity Limit, while …

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Dynamic Youngis Modulus And Axial Strain Relationships, X. J. Zhang, M. S. Aggour Mar 2001

Dynamic Youngis Modulus And Axial Strain Relationships, X. J. Zhang, M. S. Aggour

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

Equations of Young’s moduli of sands as a function of the axial strain amplitude for different types of dynamic loading were developed from a series of resonant column tests. Ottawa 20-30 sand specimens were excited longitudinally with one of three types of loading at three different confining pressures. In the sinusoidal tests, excitation signals were generated by a variable frequency sine-wave oscillator. In the random tests, input signals were generated by a white-noise generator and a pulse signal generator was used in the impulse tests. Input and output signals were analyzed by an FFT analyzer in the random and impulse …

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An Approach To Predict Shear Modulus Of Soils In The Range Of 10-6 To 10-2 Strain Levels, António Gomes Correia, Jaime Santos, José Maria C. Barros, Sussumu Niyama Mar 2001

An Approach To Predict Shear Modulus Of Soils In The Range Of 10-6 To 10-2 Strain Levels, António Gomes Correia, Jaime Santos, José Maria C. Barros, Sussumu Niyama

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

This paper presents the results of several resonant column tests carried out in a large variety of soils, including lateritic and saprolitic tropical soils. The data analysed are restricted to the strain dependence of shear modulus in the range of 10-6 to 10-2. Despite the different isotropic consolidated stresses, degrees of saturation and overconsolidation ratios applied for the different types of soil, all the test results fit very well in a previous proposed normalised curve of G/G0 as a function of γ/γ0.7, where γ0.7 is the shear strain corresponding to a value of …

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Influence Of Compaction And Loading Conditions Of The Dynamic Properties Of A Silty Sand, Jean-Marie Fleureau, Emmanuel Dufour-Laridan, Antônio Gomes Correia Mar 2001

Influence Of Compaction And Loading Conditions Of The Dynamic Properties Of A Silty Sand, Jean-Marie Fleureau, Emmanuel Dufour-Laridan, Antônio Gomes Correia

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

Elastic properties of a compacted silty sand were measured in a precision triaxial cell at the École Centrale de Paris in the range of very small strains (between 10-6 and 10-4), using improved Hall effect-based local strain gauges and data acquisition system. The dynamic properties of the soil were also derived from resonant column tests at the IST, in Lisbon, as functions of shear strain, compaction water content and confining pressure. Elastic limits as low as 5.10-6 were found in both devices, with Poisson’s ratio from triaxial tests ranging from 0.05 at very strains (< 10-4 …

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Dynamic Behavior Of Tropical Soils From Medllin, Colombia, Manuel R. Villarraga Mar 2001

Dynamic Behavior Of Tropical Soils From Medllin, Colombia, Manuel R. Villarraga

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

Medellin City has a population of about 2,000,000 people and its area is lower than 110 km2. This city is located in the northwest of Colombia, that is in the northwest corner of South America, which is a zone with a complex tectonic environment associated to the interaction of the Naza, Suramerica and Caribe plates. The result of these conditions implies that Medellin has an intermediate seismic hazard. This city was developed on tie valley of Medellin River and his slopes, has a complex geology, which is composed by alluviums, colluviums of different ages, residual soils from igneous …

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Measurement Of Dynamic Properties Of Clay Using The Downhole Freestanding Shear Device, Michael F. Riemer, Carlton Grizzle, Osama Safaqah Mar 2001

Measurement Of Dynamic Properties Of Clay Using The Downhole Freestanding Shear Device, Michael F. Riemer, Carlton Grizzle, Osama Safaqah

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

The Downhole Freestanding Shear Device is a new, in situ tool for measuring the dynamic properties of cohesive soil deposits. It has been designed and developed to perform cyclic torsional shear tests on freestanding specimens beneath the bottom of a cased borehole, with the goal of measuring local strains on soil which has not been significantly disturbed by the drilling, sampling, or unloading/reloading processes associated with conventional laboratory testing. The research team has completed the device, and is now in the process of validating its performance, first in a laboratory setting. The current paper presents results from the initial tests …

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A Study Of Soil Microstructure Using Bender Element Tests, J. Abraham Díaz-Rodríguez, Pedro Moreno-Carrizales, Luis López-Flores Mar 2001

A Study Of Soil Microstructure Using Bender Element Tests, J. Abraham Díaz-Rodríguez, Pedro Moreno-Carrizales, Luis López-Flores

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

An application of bender elements to measure the effect of soil microstructure in shear wave velocity is presented. A testing program was carried out on Mexico City sediments using a triaxial cell fitted with bender elements. Shear wave velocities were measured during isotropic consolidation and during failure. From the results of these tests simple expressions were obtained which describe the variations of shear wave velocity with the current state in terms of the effective stress and axial deformation.

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Degradation Characteristics Of Clay-Shale Samples Under Cyclic Loading, M. Zoghi Mar 2001

Degradation Characteristics Of Clay-Shale Samples Under Cyclic Loading, M. Zoghi

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

It is known that reduction and degradation of soil strength and stiffness during cyclic loading typically result in damage to structural foundations and earth structures due to excessive settlement and tilting and may cause slope instability and embankment failure. Case histories, representing damages during earthquakes, due to this phenomenon are numerous. It is the guiding principle of this paper to present an overview of degradation characteristics of combined clay-shale samples under cyclic loading and describe how this phenomenon can be utilized in evaluating the seismic stability of slopes involving colluvium.

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Infrared Thermography Of Dissipation In Soil, Minh-Phong Luong Mar 2001

Infrared Thermography Of Dissipation In Soil, Minh-Phong Luong

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

The paper introduces infrared thermography as a noncontact and non-destructive technique that conveniently offers the possibility of evaluating the energy-dissipating ability of soil, traditionally difficult to be determined using traditional techniques. It allows records and observations in real time of heat patterns produced by the dissipation of energy caused by friction between grains. Such dissipative heat occurs when soil is subjected to vibratory loading exceeding the characteristic threshold, and it evidences the distortion mechanism. This energy dissipation mechanism influences the wave speed, intergranular attenuation, and dispersion through particles contacts. The infrared thermographic technique, which couples mechanical and thermal energy, offers …

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Centrifuge Model Tests To Identify Dynamic Properties Of Dense Sand For Site Response Calculations, David Stevens, Dan Wilson, Bruce Kutter, Byoungill Kim, Ahmed Elgamal Mar 2001

Centrifuge Model Tests To Identify Dynamic Properties Of Dense Sand For Site Response Calculations, David Stevens, Dan Wilson, Bruce Kutter, Byoungill Kim, Ahmed Elgamal

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

Four centrifuge models, tested on the large centrifuge at UC Davis, are described in this paper. These four experiments involved dense profiles of Nevada Sand (Dr = 90 to 100%) tested in two different model containers. The purpose of the experiments was to evaluate numerical site response procedures by comparison with model test data. In this paper we focus on determining basic material properties of one of the models by using in-flight measurements of shear wave velocity and calculations of stress-strain relationships using data from an extensive array of accelerometers. Shear wave velocity profiles were measured at centrifuge accelerations …

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