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Articles 13411 - 13440 of 21751

Full-Text Articles in Engineering

An Experimental Investigation On Trench Isolation Techniques For Vibration Control, E. Saibaba Reddy, K. Rama Sastri, M. Abishekar Paul Mar 2001

An Experimental Investigation On Trench Isolation Techniques For Vibration Control, E. Saibaba Reddy, K. Rama Sastri, M. Abishekar Paul

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

One of the methods of controlling vibration amplitudes at source is by adopting active isolation techniques. Trench barriers are identified as methods of isolation. This paper deals with series experimental investigation carried out on block vibration tests with active isolation trench barriers. The parameters like depth of embedment, dimensions of trench, fill material in trench etc., are studied by carrying out the block vibration test in field. The results are analysed to identify the influence of those parameters.

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Uncertainties And Residuals In Ground Motion Estimates At Soil Sites, Jonathan P. Stewart, Mehmet B. Baturay Mar 2001

Uncertainties And Residuals In Ground Motion Estimates At Soil Sites, Jonathan P. Stewart, Mehmet B. Baturay

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

For a given seismic source, ground motions at soil sites can be estimated using either soil attenuation relationships, or ground response analyses with input motions scaled to match spectral ordinates from rock attenuation relationships. Ground response analyses are performed with the expectation that accounting for nonlinear sediment response improves the accuracy and reduces the uncertainty in estimated motions. Discussed here are the benefits of ground response analyses as a function of site condition. This is accomplished by preparing statistical predictions of ground motions at 36 strong motion recording sites on soil. Two predictions are made, one using a modified soil …

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Nonlinear Site Response During The 7 September 1999 Athens, Greece, Earthquake (MW 5.6), P. Dimitriu, A. Anastasiadis, N. Theodulidis, N. Klimis Mar 2001

Nonlinear Site Response During The 7 September 1999 Athens, Greece, Earthquake (MW 5.6), P. Dimitriu, A. Anastasiadis, N. Theodulidis, N. Klimis

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

The largest available strong-motion recording (PGA=0.35g), least affected by topography, structural response and/or soil-structure interaction, is investigated for possible nonlinear site response during the M, 5.9 Athens earthquake of 7 September 1999. Smoothed horizontal-to-vertical spectral ratios (HVSR) are calculated in subsequent overlapping 3.5-s windows, thus covering a wide range of excitation levels. Mean HVSR curves are computed for a so-called “weak-“ and “strong-“ motion range (mean horizontal ground acceleration in window, MGA<=10.2 cm/s/s and >=20.5 cm/s/s). The two curves have similar shape, with the “strong” curve visibly shifted toward lower frequencies relative to the “weak” one; the dominant site resonance occurs at …

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3d Fern Analysis Of Ground Vibration Measures For Stationary And Moving Transit Source, Lindita Kellezi, Niels Foged Mar 2001

3d Fern Analysis Of Ground Vibration Measures For Stationary And Moving Transit Source, Lindita Kellezi, Niels Foged

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

Ground Vibration Measures are often employed to reduce through-soil, road or railway traffic-induced disturbances or ground vibrations caused from machine foundations. This kind of problem is sometimes a major concern in densely populated urban areas situated at soft soil conditions and for structures operating sensitive equipments. In this paper a full three-dimensional (3D) FEM investigation of the effectiveness of vertical, rectangular cross-section, wave barriers (open trenches and concrete walls) in reducing ground vibrations is carried out. The reduction capacity of these measures is also compared with an array of concrete piles or sheet piles, which replaces them. The analysis considers …

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Influence Of Earthquake Source Parameters And Damping On Elastic Response Spectra, Mohsen Tehranizadeh, Farzaneh Hamedi Mar 2001

Influence Of Earthquake Source Parameters And Damping On Elastic Response Spectra, Mohsen Tehranizadeh, Farzaneh Hamedi

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

In this paper the influence of effective duration of strong motion, soil condition, magnitude and shape of accelerogram time history on elastic response spectra have been investigated. A total of 106 Iran’s horizontal acceleration components strong motion records are selected. These accelerograms are categorized in accordance with their earthquake parameters and soil condition of recording station and the influence of different soil conditions are plotted in graphs. The influence of damping ratio on the response spectra is also investigated. Analytical results show that the influence of soil condition is very significant on the shape of response spectra. The influence of …

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Seismic Response On Dense And Loose Sand Columns, Korhan Adalier, Ahmed-W. Elgamal Mar 2001

Seismic Response On Dense And Loose Sand Columns, Korhan Adalier, Ahmed-W. Elgamal

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

Densification (Compaction) of loose saturated soils has been the most popular method of reducing earthquake related liquefaction potential. Compaction of a foundation soil can be economical when limited in extent, leading to a case of an “island” of improved ground (surrounded by unimproved ground). The behavior of the densified sand surrounded by liquefied loose sand during and following earthquakes is of great importance in order to design the compacted area rationally and optimize both safety and economy. This problem is studied herein by means of dynamic centrifuge model tests. The results of two heavily instrumented-dynamic centrifuge tests on glycerin-water saturated …

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Seismic Amplification Of Typical New York City Soil Profiles, Sissy Nikolaou, Peter Edinger Mar 2001

Seismic Amplification Of Typical New York City Soil Profiles, Sissy Nikolaou, Peter Edinger

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

Amplification studies for New York City (NYC) soil sites are summarized herein. Ten (10) typical soil profiles from Brooklyn, Queens, and Manhattan, are analyzed using one-dimensional SHAKE methods. Dynamic soil properties are derived using state-of-practice correlations with standard penetration resistance and compared to available in-situ geophysical measurements. Three different rock motions are utilized, each modified from real records to match 500- and 2500-year probabilistic spectra. Results are presented in terms of dimensionless ratios of response spectra (RRS) and surface response spectra. The effect of the impedance contrast between soil and rock on soil amplification is examined. It is shown that …

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Post-Liquefaction Pore Pressure Dissipation And Densification In Silty Soils, S. Thevanayagam, G. R. Martin, T, Shenthan, J. Liang Mar 2001

Post-Liquefaction Pore Pressure Dissipation And Densification In Silty Soils, S. Thevanayagam, G. R. Martin, T, Shenthan, J. Liang

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

Pore pressure generation, and post-liquefaction dissipation and densification characteristics are data essential for detailed analysis of performance of sites containing liquefiable sands during and after earthquakes. These characteristics are also necessary for the design, analysis and choice of appropriate ground modification systems to mitigate liquefaction-induced hazards. Past research has addressed such material characteristics for clean sands. However, there are many sites that comprise non-plastic silts or silty sands have experienced liquefaction-induced damage. This paper presents results from an experimental study on silts and silty sands. Pore pressure generation characteristics are evaluated and compared with that of sands. Pre- and post-liquefaction …

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Seismic Liquefaction Assessment For The Jfk Light Rail System Project, Fathey N. Elsaid Mar 2001

Seismic Liquefaction Assessment For The Jfk Light Rail System Project, Fathey N. Elsaid

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

A procedure to evaluate seismic liquefaction potential based on ground response analysis and in-situ characteristics of the soil deposits is developed. This procedure uses the correlation between the Standard Penetration Test (SPT) N60 blow-counts, and the shear wave velocities to establish Shear Wave Velocity (SWV) profiles. The SWV profiles along with soil properties from the subswface investigation, and the design earthquake time history are then used to perform seismic response analysis for the stratified soil deposits. Cyclic Stress Ratio (CSR) profiles are determined from maximum earthquake induced shear stress profiles, based on seismic response analysis, and effective overburden pressures. …

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Seismic Evaluation And Remediation Of Embankment Dam, Nasim Uddin, J. F. Baltz Mar 2001

Seismic Evaluation And Remediation Of Embankment Dam, Nasim Uddin, J. F. Baltz

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

The seismic stability of the Croton Dam left embankment, was evaluated for potential earthquake ground motions. Field and laboratory test results were used to characterize the static and dynamic properties of the embankment and foundation materials. Results showed liquefaction and strength loss in certain zones of the embankment resulting in large deformation of the slope. Remediation of these areas of the dam was necessary. Various techniques were evaluated including drainage, construction of a berm at toe, vibro-grouted stone columns and compaction grouting. Compaction grouting was selected.

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Numerical Analysis For Seismic Behavior Of A Slope Based On A Simple Cyclic Loading Model, Akihiko Wakai, Keizo Ugai, Masayoshi Sato, Takashi Tazo Mar 2001

Numerical Analysis For Seismic Behavior Of A Slope Based On A Simple Cyclic Loading Model, Akihiko Wakai, Keizo Ugai, Masayoshi Sato, Takashi Tazo

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

A finite element simulation for dynamic centrifuge test of a slope is presented. The horizontal acceleration was applied to the base of the ground, and the response of the slope was measured. The residual deformation, accompanied with a clear slip surface, was observed after the testing. The main objective of this study is to investigate the validity of a new cyclic loading model, based on the strength parameters c - φ, and the G – γ, h - γ relationships. These features are thought to be very useful for practical usage.

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3-D Dynamic Analysis Of Taiyuan Fly Ash Dam, Jian Zhou, Yong Chi, Peijiang Qi Mar 2001

3-D Dynamic Analysis Of Taiyuan Fly Ash Dam, Jian Zhou, Yong Chi, Peijiang Qi

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

In this paper, the seismic stability of Taiyuan Fly Ash Dam in China is studied by using 3-D dynamic effective stress analysis method. The acceleration, dynamic shear stress and pore water pressure in the fly ash dam are calculated and the analysis of the seismic stability of the dam considering the seismic pore water pressure is given for different height of the dam.

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Study On Earthquake-Induced Permanent Deformation Of Earth-Rockfill Dams, Jian-Ming Zhao, Wen-Shao Wang Mar 2001

Study On Earthquake-Induced Permanent Deformation Of Earth-Rockfill Dams, Jian-Ming Zhao, Wen-Shao Wang

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

Based on the experimental data, a three-dimensional (3-D) nonlinear effective stress seismic response analysis method of earth-rockfill dams is proposed with the dissipation and diffusion of seismic pore-water pressure been considered. Then a method for evaluating the earthquake-induced permanent deformation of earth-rockfill dams taking into account both residual shear strain and residual volumetric strain is presented. The method proposed by Taniguchi is adopted to evaluate the earthquake-induced permanent deformation caused by residual shear strain. In order to evaluate the earthquake-induced permanent deformation caused by residual volumetric strain, the saturated part and the non-saturated part of the dams are treated separately. …

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Shaking Table Experiment Of A Model Slope Subjected To A Pair Of Repeated Ground Motions, Joseph Wartman, Jonathan D. Bray, Raymond B. Seed Mar 2001

Shaking Table Experiment Of A Model Slope Subjected To A Pair Of Repeated Ground Motions, Joseph Wartman, Jonathan D. Bray, Raymond B. Seed

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

This paper describes the third of a series of six shaking table experiments conducted as part of ongoing research to evaluate the accuracy and applicability of the Newmark (1965) procedure for computing seismically induced deformation in slopes. A cohesive model slope was shaken by two identical test motions in succession, mimicking a situation that commonly occurs when a preexisting landslide is subjected to strong earthquake shaking. Back analyses of the tests showed that the Newmark (1965) formulation provided moderately accurate estimates of the measured permanent deformations (within 40% to 85% of the maximum measured displacement). The accuracy of the Newmark …

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Is Newmark Method Conservative?, Mohsen Beikae Mar 2001

Is Newmark Method Conservative?, Mohsen Beikae

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

Newmark method is a commonly accepted practice in geotechnical earthquake engineering to estimate seismically induced displacement of earth structures. The method currently requires performing a series of analyses using multiple computer programs to 1) identify a potential sliding mass, 2) compute a factor of safety, 3) calculate a yield acceleration, and 4) perform a double integration of that portion of a given horizontal acceleration history that exceeds the yield acceleration. The Newmark method provides satisfactory results for a horizontal sliding surface. However, for an inclined sliding surface the result is unconservative and for a nonplanar one is not clear. To …

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Dynamic Response Of Dam-Layer System To Earthquake Excitations, Sarada K. Sarma, George Cossenas Mar 2001

Dynamic Response Of Dam-Layer System To Earthquake Excitations, Sarada K. Sarma, George Cossenas

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

An extensive database of ‘free-field’ strong motion records, from rock sites all over the world, of significant strong motion (peak ground acceleration ≥ 0.1 g) has been utilised to identify the dynamic characteristics of a typical dam-layer system. Linear elastic analysis is used to calculate the response of the dam and spectra of average seismic coefficients are presented. Attenuation relationships for the response accelerations along the height of the dam are also presented and the two methods are compared. A rigid-block model is used to calculate the earthquake-induced displacements on the body of the dam, to be used as a …

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Study Of Seismically Induced Landslide Zones, Related To Chamoli Earthquake Of 1999, Garhwal Himalaya, India, H. C. Nainwal, Ajay K. Naithani Mar 2001

Study Of Seismically Induced Landslide Zones, Related To Chamoli Earthquake Of 1999, Garhwal Himalaya, India, H. C. Nainwal, Ajay K. Naithani

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

Landslides are very common in the seismically prone areas of the Garhwal Himalaya. A seismic activity involves displacement either in vertical or horizontal direction and such displacements create slope failure by mass wastings. The maximum impact of Chamoli earthquake was experienced, in the zones of intersection of tear faults with the Main Central Thrust (MCT). During this earthquake large-scale landslides and subsidence caused destruction of many villages located over the hillside slopes. On the basis of field survey pre and post earthquake IRS IC/ID (LISS III/PAN) images, more than 100 slides have been identified in addition to the reactivation of …

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Computational Simulation Procedure For Soil-Structure Interaction Modeling In Building Seismic Damage Response, Ismail M. Ismail, Chris Mullen Mar 2001

Computational Simulation Procedure For Soil-Structure Interaction Modeling In Building Seismic Damage Response, Ismail M. Ismail, Chris Mullen

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

A finite element based computational procedure is presented for soil-structure interaction modeling in building seismic response. Attention is focused on a combination of contact surfaces at the soil-foundation interface, nonlinear soil material and infinite elements as transmitting boundary conditions. A rationale for efficient mesh design is offered for the building/foundation/soil system model based on computational wave propagation studies using infinite elements. As a the proposed procedure, a comparison is made between results of eigen mode analysis of two models for a 3-story office building, with the conventional treatment of the foundation and soil as discrete linear springs [3], and …

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Design Concept For High Speed Railway Bridges In Regions With High Seismic Activity And Soft Soil, Oliver Fischer, Andreas Maurial, Konstantin Meskouris, Carsten Könke, Falko Schube Mar 2001

Design Concept For High Speed Railway Bridges In Regions With High Seismic Activity And Soft Soil, Oliver Fischer, Andreas Maurial, Konstantin Meskouris, Carsten Könke, Falko Schube

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

At present, public transport for mid distances is more and more covered by modern high speed railway links with many examples all over the world being already under construction or in the design process. In case of soft soil conditions or urban areas, many of these projects are being realized as an elevated railway structure utilizing regular viaducts. In seismic active regions earthquake design mainly governs the overall design concept of the bridges, particularly of the piers and foundations. Thus, on the one hand, the structure has to exhibit enough stiffness under serviceability conditions (limitation of rail stresses; safety requirements …

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Dynamic Soil-Foundation-Structure Interaction Analyses Of Large Caissons, C.-Y. Chang, Chin-Man Mok, Z.-L. Wang, R. Settgast, C.-C. Chin, H. M. Gonnermann, F. Waggoner, M. A. Ketchum Mar 2001

Dynamic Soil-Foundation-Structure Interaction Analyses Of Large Caissons, C.-Y. Chang, Chin-Man Mok, Z.-L. Wang, R. Settgast, C.-C. Chin, H. M. Gonnermann, F. Waggoner, M. A. Ketchum

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

Large cellular reinforced concrete caissons exist as foundations of major long-span bridges across waterways in many parts of the country. This study was conducted to evaluate the important factors affecting the seismic response of large caissons. The paper presents the results of equivalent linear and non-linear analyses performed for a typical caisson idealized based on the cellular caisson at Pier W3 of the West San Francisco Bay Bridge subject to ground motion with a peak rock acceleration of 0.6 g. This caisson is 38.7 m (127 fi) long by 22.9 m (75 ft) wide submerged in about 32.6 m (107 …

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Dynamic Soil-Pile-Structure Interaction, Yingcai Han Mar 2001

Dynamic Soil-Pile-Structure Interaction, Yingcai Han

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

The largest compressor train in North America was installed for a new ethylene production plant at the Nova Chemicals Facility located near Joffre, Alberta. To illustrate the effect of soil-pile-structure interaction, the dynamic behavior of the structure using flexible piled foundation is compared to the same structure fixed to a rigid base in this paper. Both field and laboratory tests were carried out to investigate the soil properties including down hole seismic tests to provide soil shear wave velocities at different depths. Different design options are considered and an optimum design selected to limit vibration and produce a safe, economic …

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Seismic Analysis Of Tunnel Surrounded By Soft Soil In Shanghai, Jian Zhou, Xiaoyan Hu, Yong Chi Mar 2001

Seismic Analysis Of Tunnel Surrounded By Soft Soil In Shanghai, Jian Zhou, Xiaoyan Hu, Yong Chi

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

Based on the test results, the analysis of earthquake resistance of tunnel surrounded by soft soil in Shanghai is presented in this paper. The tunnel is located in the soft soil and sand, respectively. The reaction acceleration, pore water pressure and the settlement of the tunnel under 7-degree earthquake are given and compared.

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Effect Of Anisotropy On Drained And Undrained Shear Behavior Of In-Situ Sandy Soils, Akihiko Uchida, Munenori Hatanaka, Yuji Taya Mar 2001

Effect Of Anisotropy On Drained And Undrained Shear Behavior Of In-Situ Sandy Soils, Akihiko Uchida, Munenori Hatanaka, Yuji Taya

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

Two different types of undisturbed cylindrical specimen (V-specimen: the axis is parallel to the direction of sedimentation, and H-specimen: the axis is perpendicular to the direction of sedimentation), were prepared from high quality undisturbed sand column obtained by in-situ freezing technique. A series of drained compression and extension tests (CD, test, CD, test) and cyclic undrained triaxial tests (liquefaction test) on these samples were performed in order to investigate the effect of the anisotropy on the drained and undrained shear behavior. Following were concluded. 1) The effect of anisotropy on both internal friction angle and liquefaction strength is negligible. 2) …

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Seismic Response Calculation Of Saturated Soft Soil, Huang Yu, Ye Weimin, Tang Yiqun, Chen Zhuchang Mar 2001

Seismic Response Calculation Of Saturated Soft Soil, Huang Yu, Ye Weimin, Tang Yiqun, Chen Zhuchang

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

In this paper, Shanghai saturated soft soil is modeled as a two-phase porous media system consisting of solid and fluid phases. On the basis of resonant column test and dynamic triaxial test data of Shanghai saturated soft soil, the dynamic calculation model including a set of relationships of stress, strain, and pore water pressure and earthquake subsidence is developed to compute the seismic response of soil. The procedure to identify soil constants for the dynamic calculation model is also reported in detail. Subsequently, a dynamic effective stress analysis with the finite element method has been recommended to predict the seismic …

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Soil Viscous Behavior In Response To Torsional Cyclic Loading, Jiang Li Mar 2001

Soil Viscous Behavior In Response To Torsional Cyclic Loading, Jiang Li

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

In the present paper, experimental investigations of dynamic behavior of soils under periodic loading are conducted. Investigations include two aspects. First, effect of confining pressure and loading frequency on soil dynamic behavior and stress-strain relation is studied. Second, effect of confining pressure, loading frequency and amplitude of cyclic shear stress on soil viscosity is investigated. In the first aspect, based on test curves, physical nonlinearity shown in soil stress-strain relation suggests that physical parameters of soil materials are not constant. For example, soil elastic parameters can be a function of cyclic shear strain, confining pressure and loading frequency. In the …

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Application Of Fk Analysis Of Surface Waves For Geotechnical Characterization, Sebastiano Foti, Renato Lancellotta, Laura V. Socco, Luigi Sambuelli Mar 2001

Application Of Fk Analysis Of Surface Waves For Geotechnical Characterization, Sebastiano Foti, Renato Lancellotta, Laura V. Socco, Luigi Sambuelli

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

Since the introduction of the SASW method the use of surface waves for soil characterization has gained great popularity in geotechnical engineering. The typical two-receiver testing configuration shows some inherent drawbacks, for this reason a multistation approach is proposed in this paper. The dispersion curve evaluation with a multistation scheme has several advantages. First of all, the estimate is much more stable and less sensitive to noise and internal phases of the instruments. Moreover signal interpretation is much clearer with respect to SASW approach and there is no need for subjective choices in the construction of the experimental dispersion curve. …

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Static And Dynamic Properties Of Leighton Buzzard Sand From Laboratory Tests, Antonio Cavallaro, Michele Maugeri, Rosalia Mazzarella Mar 2001

Static And Dynamic Properties Of Leighton Buzzard Sand From Laboratory Tests, Antonio Cavallaro, Michele Maugeri, Rosalia Mazzarella

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

The Leighton Buzzard sand is an English sand commonly used at the University of Bristol to study soil-shallow foundation interaction (Maugeri et al., 1999a; 199b) and soil-retaining wall interaction (Carafa et al., 1998) by means of the shaking table. These experiments require an accurate definition of geotechnical characterisation of soil. To define the mechanical behaviour of uncemented Leighton Buzzard sand a large number of static and dynamic laboratory tests were performed on dry reconstituted specimens. The static tests includes direct shear tests performed on specimens reconstituted by pluvial deposition method with different relative density Dr. To evaluate the …

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Prediction Of Volumetric Strain For Sand Under Cyclic Loading, Habib Shahnazari, Ikou Towhata Mar 2001

Prediction Of Volumetric Strain For Sand Under Cyclic Loading, Habib Shahnazari, Ikou Towhata

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

In order to investigate volume change of sand due to cyclic loading, different tests were performed on hollow cylindrical specimens under drained cyclic simple shear condition. Correlation of accumulated plastic shear energy with volumetric strain and effects of different parameters such as initial confining pressure, initial anisotropic consolidation and strain amplitude on this correlation were studied. Test results showed that volumetric strain of sand under different initial confining pressures was almost same. Volume change of specimens with different initial anisotropic consolidations was also identical, except for initial stage of shearing. It was found that the correlation of volumetric strain and …

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Influence Of Micro-Structure On Small-Strain Stiffness And Damping Of Fine Grained Soil And Effects On Local Site Response, Anna D'Onofrio, Francesco Silvestri Mar 2001

Influence Of Micro-Structure On Small-Strain Stiffness And Damping Of Fine Grained Soil And Effects On Local Site Response, Anna D'Onofrio, Francesco Silvestri

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

Various experimental studies have shown that soil micro-structure strongly influences the small strain stiffness and damping (G0, D0) of fine-grained soils, as well as their variation with shear strain γ. This dependency, in turn, is expected to influence the local site response. This paper firstly synthesizes the dependency of G0 and D0 on stress state through power relationships, expressed in terms of dimensionless parameters, obtained by fitting a large number of experimental data collected on normally consolidated natural clays. Thereafter, these parameters were correlated to soil micro-structure, by assuming the plasticity index Ip …

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Suggestion Of Empirical Equations For Damping Ratio Of Plastic And Non-Plastic Soils Based On The Previous Studies, Dugkeun Park, Harry E. Stewart Mar 2001

Suggestion Of Empirical Equations For Damping Ratio Of Plastic And Non-Plastic Soils Based On The Previous Studies, Dugkeun Park, Harry E. Stewart

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

Several empirical correlations between damping ratio with various factors are available and many researchers have developed empirical correlations between damping ratio and normalized shear modulus. Regardless of the appearance of the equations, the estimation of the damping ratio from the normalized shear modulus at any given shear strain amplitude is possible. In this paper, thirty-two sets of normalized shear modulus versus damping ratio from ten references are used to find a new empirical equation for damping ratio of sandy soils. For clayey soils, more than forty sets of normalized shear modulus versus damping ratio from nine references are used. After …

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