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Articles 13441 - 13470 of 21751

Full-Text Articles in Engineering

Cyclic Torsional Shear Tests On Liquefaction Resistance Of Sands Under Low Confining Stress, Jinichi Koseki, Daisuke Itakura, Sadahiro Kawakami, Takeshi Sato Mar 2001

Cyclic Torsional Shear Tests On Liquefaction Resistance Of Sands Under Low Confining Stress, Jinichi Koseki, Daisuke Itakura, Sadahiro Kawakami, Takeshi Sato

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

A series of undrained cyclic torsional shear tests was conducted to investigate the effects of initial confining stress level on liquefaction resistance of sand. Hollow-cylindrical dense specimens with outer diameter of 10 cm, inner diameter of 6 cm and height of 20 cm are prepared with two kinds of sand. After being saturated, they were isotropically consolidated under an initial confining stress σc’ of 4.9, 9.8 or 98 kPa, and subjected to undrained cyclic torsional shear while maintaining the axial and lateral stresses constant. The amplitude of the cyclic torsional shear stress τcy was kept constant with …

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The Influence Of Lateral Faults In The Nonlinear Analysis In An Alluvionar Valley, Marcel Vasile Sincraian, Carlos Sousa Oliveira, J. V. Lemos Mar 2001

The Influence Of Lateral Faults In The Nonlinear Analysis In An Alluvionar Valley, Marcel Vasile Sincraian, Carlos Sousa Oliveira, J. V. Lemos

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

The nonlinear dynamic behavior of an alluvionar valley situated in São Sebastão region in Terceira island (Azores archipel) is performed. The Mohr-Coulomb model is used in this paper. A bidimensional cross-section with 1240 m long and 250 m depth is considered. The cross-section of the model is composed by layers having different type of ground, each one having their own geotechnical characteristics. The Distinct Element method is employed in this case. UDE Code is used. The size of Finite Elements has been tailored to the wavelength of the propagating waves through the layers. The objectives of this paper are: 1) …

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Improvement Of Static And Dynamic Properties Of Soft Clay Using High Pressure Jet Grout, Chang Tzyy-Shiou, Vedula V. Ramakumar, Chang Kuo-Ping Mar 2001

Improvement Of Static And Dynamic Properties Of Soft Clay Using High Pressure Jet Grout, Chang Tzyy-Shiou, Vedula V. Ramakumar, Chang Kuo-Ping

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

A proposed subway project is located in an area marked by a number of soft clay layers situated at depths from 60 ft to 100 ft below the ground surface. With unconfined compressive strength less than 0.6 tsf these natural soils are not strong enough to support on coming heavy loads and vibrations that the subway may be subject to in future. Hence the soil was trial grouted in-situ using high pressure jet grout technique to improve the engineering properties of the natural clay. A series of static and dynamic property tests were carried out on 18 samples selected from …

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Plasticity Based Liquefaction Criteria, Carmine Polito Mar 2001

Plasticity Based Liquefaction Criteria, Carmine Polito

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

Since their introduction into Chinese building codes in the 1970’s, plasticity-based liquefaction criteria have provided a means for evaluating the liquefaction susceptibility of sands with clayey fines. These criteria are used to separate soils that may be considered non-liquefiable from those susceptible to liquefaction. The majority of the proposed criteria contain some minimum requirement regarding clay content and soil plasticity. The results of a parametric study into the effects of plastic fines content and plasticity on the liquefaction susceptibility of sandy soils were used to evaluate the accuracy of several of the more commonly used plasticity-based liquefaction criteria. Most of …

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Dynamic Loading-Deformation Performance Of Peat Soil Under Large Concrete Plates, Mark Vakher Mar 2001

Dynamic Loading-Deformation Performance Of Peat Soil Under Large Concrete Plates, Mark Vakher

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

This paper presents data from a series of investigations performed with peat soil to determine resilient deformation under dynamic load, which has great influence on the design of connections between concrete plates that are used as pavement for rural roads. The experiments were performed both in situ and under laboratory conditions using a concrete plate, size 3m by 1 m by 0.15m placed over peat. Other experiments were made with the concrete plate placed over the various thicknesses of sand fill above the surface of peat soil. Experiments were carried out under dynamic load. The laboratory experiments were conducted with …

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A Review Of The Influence Of Initial State Shear (KΑ) And Confining Stress (KΣ) On Failure Mechanisms And Earthquake Liquefaction Of Soils, V. S. Pillai, B. Bmuhunthan Mar 2001

A Review Of The Influence Of Initial State Shear (KΑ) And Confining Stress (KΣ) On Failure Mechanisms And Earthquake Liquefaction Of Soils, V. S. Pillai, B. Bmuhunthan

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

Geotechnical engineering profession has continued to use the in situ measurement based empirical procedure to perform soil liquefaction analysis. This method was initially developed based on past earthquake performance of level ground sites. For sloping ground and larger depths or confining stress, the method requires appropriate corrections such as Kα for initial static shear and Kσ for confining stress. The recommended correction factors in the current state of practice have been presented by NCEER (National Center for Earthquake Engineering and Research). These recommendations, however, do not distinguish between the distinct shear behavior of soils on the opposite sides …

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Automated Analysis Procedure For Interpreting Results From Impulse Shear Tests, Wanda Henke, Robert Henke Mar 2001

Automated Analysis Procedure For Interpreting Results From Impulse Shear Tests, Wanda Henke, Robert Henke

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

In this paper, we present and discuss an automated analysis procedure for interpreting results from torsional cylindrical impulse shear tests. The “impulse shear test” is an in situ geotechnical test that provides detailed information on in situ nonlinear inelastic shearing deformation characteristics needed for dynamic geotechnical earthquake engineering analysis procedures. The test addresses the issue of effects of disturbances to in situ conditions. The automated analysis procedure is intended to be a major improvement over our existing approach for interpreting results from impulse shear tests. We demonstrate the automated analysis procedure by using the procedure to interpret results from impulse …

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Measurement Of Shear Modulus Profile Using A Continuous Surface Wave Measurement System, S. Anand, E. C. Leong, H. K. Cheong Mar 2001

Measurement Of Shear Modulus Profile Using A Continuous Surface Wave Measurement System, S. Anand, E. C. Leong, H. K. Cheong

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

For most ground response analyses, the shear modulus is an important parameter to be determined and it has to be measured over a large strain range, so as to characterise the soil behavior under various loading conditions. Laboratory measurement of shear modulus covers a limited strain range depending on the test method. The main difficulty lies in the determination of the shear modulus at very small strains. In this respect, geophysical methods are more attractive. One of these test methods, which uses a continuous surface wave, is used to obtain the shear modulus profile at two sites in Singapore. The …

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Post-Liquefaction Torsion Shear Tests On Sand With Various Strain Rates, Kiyoshi Kokeguchi, Atusushi Shimokawa, Jun Kohchi, Ikuo Towhata Mar 2001

Post-Liquefaction Torsion Shear Tests On Sand With Various Strain Rates, Kiyoshi Kokeguchi, Atusushi Shimokawa, Jun Kohchi, Ikuo Towhata

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

This text concerns with the deformation characteristics of liquefied sand which undergoes large residual deformation and flow failure. In particular, the nature of sand which can be used in a dynamic analysis of deformation in the time domain is aimed at. Although the former model tests have suggested a rate-dependent behavior of sand, a detailed measurement of stress and strain was not possible. This problem was overcome in the present study in which two types of torsional shear device were employed. A special care was therein taken to achieve such a large and realistic shear strain as 100% in a …

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Identification Of Small Strain Dynamic Properties Of Dense Sand, Ahmed Elgamal, Tao Lai, Dan Wilson, Bruce Kutter Mar 2001

Identification Of Small Strain Dynamic Properties Of Dense Sand, Ahmed Elgamal, Tao Lai, Dan Wilson, Bruce Kutter

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

System identification techniques are employed to characterize the stiffness and damping characteristics of a dense sand stratum at low dynamic excitation conditions. The identification process utilizes a large database of input-output accelerations recorded in a highly instrumented centrifuge experimental program conducted by researchers at the University of California at Davis. This paper presents a computational effort based on the recorded small shaking events, where the peak ground surface acceleration ranges from 0.05g to 0.196g in amplitude. The dynamic behavior of the prototype stiff soil site near its first resonance is modeled by that of a one-dimensional shear beam. An employed …

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Systematic Protocol For Sasw Inversion, Karen T. Marosi, Dennis R. Hiltunen Mar 2001

Systematic Protocol For Sasw Inversion, Karen T. Marosi, Dennis R. Hiltunen

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

Spectral-analysis-of-surface-waves (SASW) is a nondestructive test method for characterization of the variation with depth of the shear modulus of soils. One drawback in SASW is the need for an experienced user to conduct the inversion. Difficulty in SASW inversion arises from lack of constraint of the least squares minimization used on shear wave velocity parameters. For even simple profiles. The inversion algorithm can exhibit instability due to numerical sensitivity of the forward model calculations. The user must provide a reasonable starting profile; and then the parameters must be carefully followed and constrained to reach convergence. The inversion process was explored …

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Determination Of The Zone Of Destruction Of Soil And Rock Mass At Explosive Loads, B. E. Khusanov Mar 2001

Determination Of The Zone Of Destruction Of Soil And Rock Mass At Explosive Loads, B. E. Khusanov

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

This paper studies the behavior of grounds and rock mass under explosive loads using a new worked out model of deformation of ground and rock mass accounting structural destruction of grounds. Here mechanical characteristics of grounds are the functions on the degree of structural destruction (on the second invariant of the deviator of deformation). The problem on excitation propagation from hemispherical cavity cut from ground half-space, to the sides of this cavity a load is applied, imitating the action of explosion. The problem is solved numerically - by the method of finite differences according to the scheme offered by Wilkins …

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Shear Wave Velocity Relations For Silty And Gravely Soils, S. Thevanayagam, J. Liang Mar 2001

Shear Wave Velocity Relations For Silty And Gravely Soils, S. Thevanayagam, J. Liang

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

Shear wave velocity vs, dynamic shear modulus Gmax, and damping characteristics are important parameters required for both static and dynamic response analyses of earth structures. Traditional indirect methods for estimation of these parameters based on void ratio, relative density, and mean effective stress have been successful for rather narrowly graded soils, but not for the most commonly found silty and gravelly soils. Their direct application to determine the above characteristics for silty and gravely soils are not satisfactory. A primary reason for this is that global void ratio is not a good measure of intergrain contact …

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Ground Waves Generated By Pile Driving, And Structural Interaction, C. L. Ramshaw, A. R. Selby, P. Bettess Mar 2001

Ground Waves Generated By Pile Driving, And Structural Interaction, C. L. Ramshaw, A. R. Selby, P. Bettess

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

Pre-formed steel or concrete pile elements are installed by high energy impact or vibro-driver, which causes outgoing ground waves. In severe cases, adjacent buildings are at risk of damage. Assessment of risk is conventionally by reference to threshold limits of vibration. The global approach considers neither the interactive effects between ground and structure, nor frequency and duration. Here, firstly, the dynamics of a pile head impact and of the transmission of a portion of the energy into the ground were modelled by a combination of finite elements (FE), springs and dashpots. The boundary disturbances were then applied to a second …

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Analysis Of Dynamic Compaction Of Loose Soils Under Impact Loads, J. L. Pan, A. R. Selby Mar 2001

Analysis Of Dynamic Compaction Of Loose Soils Under Impact Loads, J. L. Pan, A. R. Selby

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

Dynamic compaction has become a popular method world-wide for deep improvement of loose soils in recent years. The method involves the repeated application of high-energy impacts on the soil surface using tampers weighing 10-20 Mg, dropping from heights of 10-20 m, compacting the soil strata to a considerable depth. Previous analytical methods have been used to investigate the effectiveness of dynamic compaction of loose soils, most of which were based on a rigid tamper striking a vertical soil column represented by springs, masses and dampers. This study analysed the dynamic compaction of loose soils under impact loads numerically, using ABAQUS© …

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Estimation Of Ground-Borne Vibrations From Moving Trucks, Raj V. Siddharthan, Mohey El-Mously Mar 2001

Estimation Of Ground-Borne Vibrations From Moving Trucks, Raj V. Siddharthan, Mohey El-Mously

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

The paper focuses on providing details on the application of a continuum-based finite-layer model to estimate ground-borne vibrations induced by moving trucks. The computational model incorporates important pavement response factors such as the noncircular contact area, complex 3-D contact stress distributions (normal and shear), vehicle speed, and viscoelastic material characterization. The proposed method is much more computationally efficient than the moving-load models based on the finite element method. Predictive capability of the approach relative to vehicle-induced vibrations has been demonstrated using realistic pavement loading. As an important design application, particle velocity responses from conventional dual and its recent substitute, viz. …

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Numerical Study On The Behaviour Of Structures In The Near-Field Of Sheet-Pile Driving Work, H. Meissner, A. Becker Mar 2001

Numerical Study On The Behaviour Of Structures In The Near-Field Of Sheet-Pile Driving Work, H. Meissner, A. Becker

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

The process of sheetpile-driving is investigated. Emphasis is placed on the influence of actual pile driving depth and the transfer of pile driving energy from the sheetpile to the surrounding soil. The propagation of waves caused by the pile driving and its effects on the soil and structures founded in and on the ground are discussed. Horizontal and vertical displacements of structures on the surface as well as in half space (e.g. buried pipelines) are presented. The results were obtained using the finite element method. The central point of these first studies is to show the effect of sheetpiling works …

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Comparison And Modeling Of Sand Behavior Under Cyclic Direct Simple Shear And Cyclic Triaxial Testing, J.-F. Vanden Berghe, A. Holeyman, R. Dyvik Mar 2001

Comparison And Modeling Of Sand Behavior Under Cyclic Direct Simple Shear And Cyclic Triaxial Testing, J.-F. Vanden Berghe, A. Holeyman, R. Dyvik

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

Constant volume cyclic shear (DSS) tests were performed on Brusselian sand using the new NGI simple shear apparatus and a special control system for cyclic strain controlled testing. Test results are compared with those from cyclic triaxial (TXS) tests. The tests investigated the degradation of the cyclic shear modulus for different relative densities (from 60% to 90%), different consolidation pressures (from 5OkPa to 200kPa) and different shear strain amplitudes (from 0.1% to 9%). The comparison of the soil specimen behavior in the two different test types shows that soil degradation is mainly function of (1) the dilative or contractive behavior …

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Dynamic Interaction Between Rail Track Systems And The Layered Subsoil Solutions In The Frequency-And Time Domain, S. Savidis, S. Bergmann, C. Bode, R. Hirschauer Mar 2001

Dynamic Interaction Between Rail Track Systems And The Layered Subsoil Solutions In The Frequency-And Time Domain, S. Savidis, S. Bergmann, C. Bode, R. Hirschauer

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

For the numerical simulation of dynamic soil-structure interaction problems both a frequency and a time domain formulation are presented. In order to be capable to consider more sophisticated models of the structure, the frequency domain algorithms for homogeneous and layered halfspaces have been coupled to the Finite Element Program ANSYS. Flexibility functions are presented for a concrete slab track system. Furthermore the stress distribution in the subsoil is calculated and visualized. The time domain formulation is applied for demonstrating the basic phenomena of a moving load passing by with sub- and supercritical speed. Besides that, a nonlinear, tension-free condition of …

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Vertical Earthquake Response Analysis Of Xiaolangdi Earth-Rock Dam With 3-D Shear Wedge Model, Zhenzhong Shen, Zhiying Xu Mar 2001

Vertical Earthquake Response Analysis Of Xiaolangdi Earth-Rock Dam With 3-D Shear Wedge Model, Zhenzhong Shen, Zhiying Xu

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

The constructing Xiaolangdi dam is the highest earth-rock dam in China. Its maximum height is about 154 m, and the length of dam axis is about 1500 m. In this paper, by application of the three-dimensional shear wedge theory and the Bubnov-Galerkin approach method, the vertical earthquake response analysis is performed for the earth dam. Its dynamic behaviors such as maximum dynamic displacement, velocity, acceleration and stress etc. are obtained. Under the action of the designed earthquakes, the fundamental period of the vertical vibration of the Xiaolangdi earth-rock dam is about 0.803 s, the maximum acceleration response is about 0.976 …

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Surface Waves In Evaluation Of Damping In Layered Systems, Nenad Gucunski, Ali Maher Mar 2001

Surface Waves In Evaluation Of Damping In Layered Systems, Nenad Gucunski, Ali Maher

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

The Spectral analysis of surface waves (SASW) method has been successfully used in evaluation of elastic moduli profiles of layered systems. Recently, there have been attempts to implement the SASW method and surface waves in evaluation of damping/attenuation properties of layered systems. Results of numerical simulations are presented for the purpose of explanation of effects of damping properties of individual layers on the overall attenuation properties, as measured during actual SASW testing. A parametric study conducted examines effects of a number of parameters, including the system stratification that may lead to dominant wave propagation in terms of higher Rayleigh modes. …

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Vibration Of Synchrotron Foundation Due To Ground-Transmitted Excitation, M. Hesham El Naggar, Bruce F. Sparling Mar 2001

Vibration Of Synchrotron Foundation Due To Ground-Transmitted Excitation, M. Hesham El Naggar, Bruce F. Sparling

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

The Canadian Light Source (CLS) is a third generation synchrotron that will be capable of generating a wide spectrum of electromagnetic radiation used in the study of the atomic and sub-atomic structure of materials. The CLS facility will feature a 50 m diameter vacuum storage ring used to contain a highly focused stream of electrons. The accuracy required in aiming the electron beam and resulting radiation necessitates very stringent operational tolerances on foundation vibrations, with peak dynamic displacements being limited to less than 0.35 μm. To assess the level of seismic excitation at the site due to traffic on an …

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Vertical Vibrations Of Block Foundations, Vijay K. Puri, Braja M. Das Mar 2001

Vertical Vibrations Of Block Foundations, Vijay K. Puri, Braja M. Das

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

Steady state vertical vibration tests were conducted on test blocks measuring 1.5m x 0.75m x 0.7 m and 3m x 1.5m x 0.7m resting on ground surface. The amplitudes of vibration the blocks were measured at different frequencies. Dynamic shear modulus of the soil at site was also determined by conducting in-situ tests. The natural frequencies and amplitudes of vibration were calculated by (i) elastic half space method and (ii) impedance function method. A comparison was then made of the observed and the computed values natural frequencies and the vibration amplitudes. The data obtained shows that for this case the …

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Partially Embedded Rectangular Foundations: A Simplified Approach To Compute Dynamic Stiffnesses, Toyoaki Nogami, Ham Shean Chen Mar 2001

Partially Embedded Rectangular Foundations: A Simplified Approach To Compute Dynamic Stiffnesses, Toyoaki Nogami, Ham Shean Chen

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

Partially embedded rectangular foundations are considered. Soil at the side of the foundation is decoupled from that at the base and is treated as a stack of horizontal layers of unit thickness that are mutually uncoupled. The side soil stiffnesses/depth are formulated from the vibration of a massless rigid rectangular disc in an individual layer. In the development of formulations, the layer medium is further simplified with a column-spring system. All these simplifications lead to simple expressions suitable for practical use. The two parameters in these expressions are defined by iteration using two coupled simple equations. Dynamic soil stiffesses at …

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Evaluating The Response Of Soils To Seismic Tremors By Recording Background Noise, Rabah Iddir, Nadir Laradi Mar 2001

Evaluating The Response Of Soils To Seismic Tremors By Recording Background Noise, Rabah Iddir, Nadir Laradi

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

At 29/10/1989, Tipaza’s region situate in the west of Algiers, was vibrate below a Chenoua earthquakes. A distance between the centre of this earthquakes and Algiers the capital, wasn’t a to make a damages for the constructions (Casbah, Bab El Oued, Hamma, Tagara...). Because this one is dating for the colonial era, and haven’t a para-seismic structures. Then determination of zonal effects is one of the essential components of para-seismic prevention, having recourse to macro-zoning. The conventional method of measuring zonal effects experimentally is based on seismic recording. It is admittedly reliable, but it is laborious We suggest in this …

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Behavior Of Dune Sands Of The Thar Desert Under Dynamic Loading, Sanjay Gupta, Ravi Sundaram Mar 2001

Behavior Of Dune Sands Of The Thar Desert Under Dynamic Loading, Sanjay Gupta, Ravi Sundaram

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

Forced vibration test were conducted on concrete blocks for a power project in north-western Rajasthan (India). The site is in the Thar desert and has meta-stable aeolian sand deposits. At shallow depth, the amplitude versus frequency curves shows two peaks, suggesting that the soil structure was probably collapsing and settling under the dynamic load. Tests conducted on the deeper, relatively more stable soils confirm a good response to dynamic loads. The instability under static loading conditions is also highlighted and correlated to the dune morphology.

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Site Effect Evaluation Using Combination Of Source Scaling Models And Ground Motion Records, Vladimir Sokolov, Chin-Hsuing Loh, Kuo-Liang Wen Mar 2001

Site Effect Evaluation Using Combination Of Source Scaling Models And Ground Motion Records, Vladimir Sokolov, Chin-Hsuing Loh, Kuo-Liang Wen

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

We analyze site response of the Taipei basin using the records obtained by the Taiwan Strong Ground Motion Instrumentation Program (TSMIP) network. Records of 66 earthquakes of M=2.6-6.5 with a hypocentral depth varying from 1 km to 118 km and hypocentral distances of up to 150 km are studied for 35 stations located within this triangle shaped alluvium structure. The site response is obtained in terms of spectral ratios calculated by dividing of the site spectrum by the reference spectrum estimated for a hypothetical “very hard rock” site. The recently developed empirical source scaling and attenuation models are used for …

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Site Response Analysis Using Forced-Vibration Tests On Hydraulic-Filled Soil Deposit, Dong-Soo Kim, Jin-Sun Lee Mar 2001

Site Response Analysis Using Forced-Vibration Tests On Hydraulic-Filled Soil Deposit, Dong-Soo Kim, Jin-Sun Lee

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

Forced vibration tests and detailed site characterization were performed at a geotechnical experimental site in Yong-jong Island where Inchon International Airport being constructed. The vibratory motions generated by the combination of hydraulic hammer compaction and dynamic compaction were monitored by 3-component velocity transducers in the down hole array as well as on the ground surface. Spectral analyses of the recorded vibratory motions were performed to evaluate the resonant frequencies of the experimental site. The linear analysis and simplified method were also performed to evaluate the resonant frequencies of the experimental site based on the results of detailed site investigation. The …

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New-Generation Objective And Reproducible Isoseismals, And Tests Of Source Inversion Of The Usgs "Felt Reports", Franco Pettenati, Livio Sirovich Mar 2001

New-Generation Objective And Reproducible Isoseismals, And Tests Of Source Inversion Of The Usgs "Felt Reports", Franco Pettenati, Livio Sirovich

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

We present two new techniques for treating earthquake intensity data objectively and reproducibly. First, our natural-neighbor, n-n, isoseismals (program: ConVor) are used to draw objective and reproducible isoseismals of the Whittier Narrows ML=5.9, 1987 earthquake from the earthquake damage (“felt reports”) sparsely observed in the region by the U.S.G.S. ConVor uses the n-n coordinates to weight and interpolate the observations; thus, the weights of the experimental sites which are natural neighbors to a new point are proportional to the areas of the intersections of their Voronoi polygons. It is shown that the n-n isoseismals: 1) honour the experimental …

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Simple Power-Law Characterization Of Transient Ground-Borne Vibrations, Michael L. Rucker, Otto C. Holmquist Mar 2001

Simple Power-Law Characterization Of Transient Ground-Borne Vibrations, Michael L. Rucker, Otto C. Holmquist

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

Practical characterization of transient ground-borne vibrations in civil and geotechnical engineering problems is often a difficult and frustrating task. Some modem engineering seismographs now routinely permit the collection of histogram-type data where the peak vibration for a pre-set time interval can be measured and stored for significant time periods. Such data is amenable to analysis utilizing concepts of fractal geometry and self-ordered criticality. Resulting data trends tend to follow power-law relationships that plot as essentially straight lines in log-log space. This application is similar to the Gutenberg-Richter relationship for earthquakes where the relationship between magnitude and frequency is fractal. However, …

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