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International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Articles 181 - 201 of 201
Full-Text Articles in Civil and Environmental Engineering
The Influence Of Viscoelastic Damping On The Dynamics — Behavior Of An Embedded Foundation, A. P. S. Selvadurai
The Influence Of Viscoelastic Damping On The Dynamics — Behavior Of An Embedded Foundation, A. P. S. Selvadurai
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The present paper examines the problem of the dynamic behavior of a rigid circular foundation deeply embedded in bonded contact with a viscoelastic soil mass of infinite extent. The viscous phenomena are accounted for by the introduction of a complex shear modulus. By employing a rigorous mathematical analysis of the problem an explicit results is derived for the dynamic axial compliance of the embedded foundation. The numerical results presented in the paper illustrate the manner in which viscous damping influences this compliance.
Probabilistic Response Of Multi-Support Structures On Non-Uniform Soil Conditions, S. E. Ruiz, L. Esteva
Probabilistic Response Of Multi-Support Structures On Non-Uniform Soil Conditions, S. E. Ruiz, L. Esteva
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Conventional seismic design criteria take values of internal forced and other response variables as those provided by an envelope to the values of those variables produced by in-phase motion of all supports. In structures extended in plan, such as long bridges, or founded on heterogeneous formations or irregular topography, such as dams, differences in ground motion among different supports may give to differences as compared with those produced by conventional analysis. In this paper ground motion is represented as stochastic process with evolutionary intensity and frequency content. A criterion for determining design responses, based on the variance of the response …
Method Of Influence Function And Its Application, Y. S. Wang, K. C. Wang, T. Q. He
Method Of Influence Function And Its Application, Y. S. Wang, K. C. Wang, T. Q. He
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Within the limited space, the authors have aimed to present concisely final forms of influence function of circle center displacement due to either suddenly or harmonically acted vertical load uniformly distributed over circular area on the surface of an elastic half-space, along with formulae of the method of influence function of circle center displacement for determination of the vertical displacements of points outside and inside the bases of circular, ring and rectangular foundations, as well as the average displacement of these bases. The determination of the parameters of the lumped analog for vibration of the rectangular foundations has also been …
Free Field And Design Motions During Earthquakes, T. Iwasaki
Free Field And Design Motions During Earthquakes, T. Iwasaki
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Recent development of free field ground motions and structural design motions are described with emphasis on investigations done in Japan. The results of analyses of peak free field accelerations and frequency characteristics of response spectra are discussed. Also the recent topics of studies on ground motions including strong-motion earthquake instrument arrays and soil-structure interaction problems are described with use of the results of measurements of strong -motion earthquakes.
Effect Of Soil Parameters On High Velocity Projectile Penetration, D. Z. Yankelevsky
Effect Of Soil Parameters On High Velocity Projectile Penetration, D. Z. Yankelevsky
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
A parameter analysis is performed on an analytical penetration model which has been recently developed. Figures are plotted to show how the disturbed zone size, parameters of displacement and stress fields and dynamic section pressure are dependent on soil compressibility, shear strength and mass density. Main results are presented and discussed.
Explosion Codas And Design Seismic Coefficient, S. K. Guha, S. S. Patil, J. G. Padale
Explosion Codas And Design Seismic Coefficient, S. K. Guha, S. S. Patil, J. G. Padale
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
In view of construction of structures in seismic zones like high dams, nuclear power plants etc., evaluation of ‘site dependent design seismic coefficient’ has been of paramount importance. It is thus necessary to assess correctly ‘amplification factor’ of ground motion due to surface geology during earthquakes. This ground amplification factor depends on ‘predominant period’ of site in addition to other factors according to Kanai and others. Though micro tremors have been utilized for estimation of predominant period of site, it has been shown that explosion generated codas could also be used to obtain ground amplification factor useful for estimation of …
Dynamical Behavior Of A Pile Under Earthquake Type Loading, T. Kobori, R. Minai, K. Baba
Dynamical Behavior Of A Pile Under Earthquake Type Loading, T. Kobori, R. Minai, K. Baba
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
In order to obtain a theoretical prediction on the seismic response of the soil-pile structure systems, the frequency response of the soil-pile system excited by ground incident waves may be necessary in addition to the response due to the excitation at the pile head. This paper is concerned with a theoretical analysis based on the three-dimensional wave propagation theory to find dynamical interaction characteristics of an elastic pile embedded in the viscoelastic soil stratum on a rigid bed rock, subjected to a concentrated external force or forced displacement at the pile head and to uniformly distributed bed rock motion. In …
Response Of Multiple-Mass Systems To Nonvertically Incident Seismic Waves, J. Bielak, J. A. Coronato
Response Of Multiple-Mass Systems To Nonvertically Incident Seismic Waves, J. Bielak, J. A. Coronato
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
A variational procedure is used for calculating the response of two foundations with rectangular bases supported on a viscoelastic halfspace and subjected to horizontally and vertically incident SH-waves and Rayleigh waves. Results which include the response of massless foundations and those with mass indicate that the dynamic behavior of a rigid foundation to traveling wave excitation can be affected significantly by the presence of a neighboring foundation. The effect is most pronounced when the direction of the incoming wave is parallel to the axis of the two masses, in which case a noticeable reduction in the response of the downstream …
Free Response Of Shells On Flexible Foundation, R. M. Belkune, J. C. Vyas
Free Response Of Shells On Flexible Foundation, R. M. Belkune, J. C. Vyas
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Free response of axisymmetric shells resting on flexible foundation in their asymmetric modes is studied using Finite Elements based on harmonic formulation. Influence of various parameters, such as subgrade modulus, proximity of boundary, density ratio, shear wave velocity, embedment of structure and depth of flexible foundation., on free response is studied. Axisymmetric interface element with harmonic functions is developed and introduced between the raft slab and foundation media.
Dynamic Response Of An Embedded Structure Generated By A Sh-Wave, G. S. Yeh, T. W. Lin
Dynamic Response Of An Embedded Structure Generated By A Sh-Wave, G. S. Yeh, T. W. Lin
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
In this investigation, a mathematical hybrid model developed previously is employed to study soil-structure interaction of embedded structure. In the analysis, the near field including the embedded structure and its surrounding foundation soil is modelled with a conventional finite element mesh, and the far field is modelled as a semi-infinite medium with a hemi-spherical pit. The impedance functions at the nodes around the special element, which have been determined analytically, can represent the behavior of outgoing propagation of waves. A concept of superposition is proposed to analyze the response of an embedded structure excited by an incoming SH-wave. The governing …
Scale Modelling Of Soil Structure Interaction During Earthquakes Using A Programmed Series Of Explosions During Centrifugation, A. Zelikson, B. Devaure, D. Badel
Scale Modelling Of Soil Structure Interaction During Earthquakes Using A Programmed Series Of Explosions During Centrifugation, A. Zelikson, B. Devaure, D. Badel
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Scale models of Nuclear Power plants were constructed to study soil structure interaction during Earthquakes. The centrifuge of the C.E.S.T.A. Center near Bordeaux, France, was used to simulate gravity at 100 g (length scale 1: 100) on a 1000 kg net weight of soil and structure. The Earthquake was simulated by a surface wave created by a programmed series of small explosions suitably modified so that the free field signals of horizontal and vertical accelerometers had spectra resembling those of real Earthquakes according to similitude laws. The problem of echoes and suitability of a confined structure was studied without models …
Dynamic And Earthquake Geotechnical Centrifuge Modelling, A. N. Schofield
Dynamic And Earthquake Geotechnical Centrifuge Modelling, A. N. Schofield
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
This state of art review discusses scaling principles for dynamic and earthquake geotechnical centrifuge models that have been known for many years, and shows how the new emphasis on modelling of models using reconstituted soil helps to reduce the difficulties of verification of these principles. It is suggested that models made of reconstituted soil can exhibit a wide range of behavior that is important in the field. In particular it is suggested that liquefaction and cracking are related phenomena which can both be modelled.
Dynamic Excitation For Geotechnical Centrifuge Modelling, J. A. Cheney
Dynamic Excitation For Geotechnical Centrifuge Modelling, J. A. Cheney
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The method of physical modeling in the centrifuge is growing in acceptance in the U.S.A. following many years of use in U.S.S.R., Denmark, England, Norway, France and Japan. Simulation of dynamic events (machine vibration, wave forces, and earthquake) in modeling in the centrifuge has important applications, especially on the large national Geotechical Centrifuge being constructed at NASA-ARC. The most difficult problem is that of earthquake simulation. Several schemes for light weight shakers have been proposed in a Workshop on Dynamic Excitation for Geotechnical Centrifuge Model Testing held in August, 1979. More recently, a scheme has been presented which utilizes traveling …
Initial Results From A Stacked Ring Apparatus For Simulation Of A Soil Profile, R. V. Whitman, P. C. Lambe, B. L. Kutter
Initial Results From A Stacked Ring Apparatus For Simulation Of A Soil Profile, R. V. Whitman, P. C. Lambe, B. L. Kutter
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
A stack of 48 rings, lined with a latex membrane, is used to confine a column of soil 12 inches high by 12 inches in diameter (300 mm x 300 mm). Both dry and saturated columns of fine sand are shaken at their base, at a centrifugal acceleration of 35.5 g. Measurements of the settlement of the surface, horizontal displacement and pore pressures show that the columns of soil are behaving essentially (although not exactly) as one-dimensional shear beams.
Scaling Considerations For Dynamic Experiments, R. M. Schmidt
Scaling Considerations For Dynamic Experiments, R. M. Schmidt
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The geotechnical centrifuge has been shown to be a very valuable experimental technique in the investigation of explosive and impact cratering behavior. A brief summary of recent experiments is given along with a pertinent bibliography. These works have served to establish the practicality of performing dynamic experiments on the centrifuge as well as to provide a theoretical basis for their interpretation.
Behavior Of Clays Subjected To Slow Cyclic Loading And Large Strains, Adel Sada, Louise Shook
Behavior Of Clays Subjected To Slow Cyclic Loading And Large Strains, Adel Sada, Louise Shook
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
One of the major considerations in the design of offshore structures is the effect of wave action on the foundation. This requires a study of the effects of cyclic loading on the soil properties. The anisotropic nature of clay soils, which results from sedimentation followed by K0 consolidation, plays an important role in its dynamic as well as its static behavior. An experimental program was undertaken to determine the trends in behavior of clays subjected to large strain cyclic loading. Thin long hollow cylinders of isotropic, and normally K0 consolidated and over consolidated clays, with varying degrees of anisotropy and …
Long-Term Measurements Of Ground Motions Offshore, Eric W. Reece, David E. Ryerson, Robert L. Mcneill
Long-Term Measurements Of Ground Motions Offshore, Eric W. Reece, David E. Ryerson, Robert L. Mcneill
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Long-Term measurements of earthquake ground motions offshore, using the Sandia National Laboratories' SEMS device which records only the strongest motions and transmits them upon command to a boat at the surface, have shown that offshore ground motions may in certain cases be substantially different from empirically predicted ground motions based on onshore data. In particular, the attenuation effects of soft and/or gassy soils, the wedging of offshore deposits as a function of direction to and distance from the source, and sharp velocity-depth profiles, are shown to be possible actors contributing to such differences. For the well constrained recording to date, …
Offshore Caissons On Porous Saturated Soil, George Gazetas, Emmanuel Petrakis
Offshore Caissons On Porous Saturated Soil, George Gazetas, Emmanuel Petrakis
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
While currently available methods of dynamic soil-foundation interaction idealize the soil as a continuum, this paper presents a general theory to obtain the dynamic response of offshore caissons resting on a saturated or nearly saturated poroelastic medium. The model, based on Biot's theory, considers the compressibility of both solid and fluid phase and assumes that the fluid flow is governed by Darcy's Law for an isotropic medium. Results are presented as plots of normalized amplitudes of displacement load or rotation-moment ratios for a rigid strip founded on a dense coarse sand. The results demonstrate that fluid compressibility, which is primarily …
Offshore Earthquake Geotechnology — First Part, P. B. Selnes
Offshore Earthquake Geotechnology — First Part, P. B. Selnes
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
This first part of the paper outlines the problems encountered offshore compared to onshore. The most important difference is the presence of water which changes the dynamic behavior of structures, introduces new forces, complicates the soil investigation and visual site inspection, and changes the characteristics of the earthquake ground motion. Furthermore, the structures offshore may be much larger than most onshore facilities, and other environmental loads may act simultaneously with an earthquake.
Offshore Earthquake Geotechnology — Second Part, P. B. Selnes
Offshore Earthquake Geotechnology — Second Part, P. B. Selnes
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
This second part of the paper discusses submarine slides and acoustic waves from earthquakes, and gives a general overview of aseismic design procedures. Problems which are specific or especially important for the offshore environment are pointed out and discussed in more detail.
Seismic Design Of The San Francisco Ocean Outfall, O. H. Gilbert Jr., Y. Eisenberg, D. D. Treadwell
Seismic Design Of The San Francisco Ocean Outfall, O. H. Gilbert Jr., Y. Eisenberg, D. D. Treadwell
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
San Francisco's Southwest Ocean Outfall will extend four miles into the Pacific Ocean. Offshore, the Outfall will cross the San Andreas Fault zone. Major design concerns for the 12-foot inside diameter reinforced concrete pipe included seismic foundation stability, backfill liquefaction, and rupture by fault displacement. Foundation stability was achieved by selection of adequate embedment depths. A coarse pervious backfill to preclude liquefaction-induced pore water pressure gradients was selected based on analyses with the computer program APOLLO. Special joints were designed within and adjacent to the fault zone to limit damage due to fault rupture and to accommodate deformations away from …