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Full-Text Articles in Geotechnical Engineering
Embedment Effect On Foundations Under Vertical Vibrations, Swami Saran, Gopal Ranjan, R. C. Vijayvargiya
Embedment Effect On Foundations Under Vertical Vibrations, Swami Saran, Gopal Ranjan, R. C. Vijayvargiya
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The dynamic response of the embedded foundation subjected to vertical dynamic loads has been studied through carefully conducted field tests. The block was excited in vertical and coupled modes of vibrations. Four excitation levels were used. Tests, with different embedment depths were carried out. The foundation block was instrumented to monitor dynamic contact pressure at various embedments with specially designed contact pressure cells. Side shear resistances were measured through dynamic shear resistance cells specially designed for the purpose. Also, frequency amplitude characteristics were observed during each test .The analysis of data indicates that as the depth of embedment increases, damping …
Axisymmetric Soil-Structure Interaction By Substructure Approach, P. K. Basu, B. J. Lee
Axisymmetric Soil-Structure Interaction By Substructure Approach, P. K. Basu, B. J. Lee
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The effect of soil-structure interaction is incorporated into an existing finite element computer program for axisymmetric shells and plates using substructure approach and energy transmitting boundaries. The results of numerical experimentation for a tall chimney and a typical hyperboloidal cooling tower are presented.
Session 4: Opening Remarks, K. Rainer Massarsch
Session 4: Opening Remarks, K. Rainer Massarsch
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
No abstract provided.
Seismic Response Of Pile Supported Structures, William E. Saul, Tuncer B. Edil, Yong-Wu Chang
Seismic Response Of Pile Supported Structures, William E. Saul, Tuncer B. Edil, Yong-Wu Chang
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Earthquake loads are applied to the foundation mainly through shear waves in the underlying soil. A method is presented for analyzing the alteration in the response of a structure by adding piling to the foundation. The method of computation consists of a series of transfer matrices which are used to form a stiffness matrix of the foundation system. Central to the computation is the modelling mode for the soil-pile interaction; several alternatives are presented. Observations regarding the effect of several design parameters, based on a numerical example, are discussed.
Studies Of Apparent Seismic Wave Velocity, A. H. Hadjian, D. M. Hadley
Studies Of Apparent Seismic Wave Velocity, A. H. Hadjian, D. M. Hadley
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Apparent seismic wave velocities are studied by comparing the stress results obtained by a computer simulation with those obtained by a commonly used simplified engineering model. Two earth models with significantly different surface layers and two focal depths of energy release are used. The results from all four cases studied show that the apparent wave velocity at the free surface is determined by the properties of the material at depth where energy is released. A secondary, yet significant conclusion is the fact that the simplified plane wave propagation solution is a good predictor of the strains/stresses due to seismic waves, …
Dynamic Response Of Rigid Circular Footings, Shenbaga R. Kaniraj
Dynamic Response Of Rigid Circular Footings, Shenbaga R. Kaniraj
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
In a simplified approach to the rigorous elastic half-space approach for the behavior of a rigid circular surface footing acted upon by a dynamic excitation force, the elastic half-space model is replaced by an equivalent lumped parameter system. The equivalent spring constant (K) and the equivalent damping factor (D) are expressed in terms of dimensionless mass ratio (B). A chance in the value of B thus affects the dynamic response of the footing. The paper explains a procedure to quantify this variation £or vertical mode of vibration.
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.
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 …
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 …
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 …
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 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.
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 …
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 …
Exceptional Issues In Offshore Earthquake Geotechnology, R. G. Bea
Exceptional Issues In Offshore Earthquake Geotechnology, R. G. Bea
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
This Moderator's Report reviews the state-of-the-art report and papers submitted to the session on Offshore Earthquake Geotechnology. Selection of earthquake intensity and characteristics of ground motions for design of offshore structures, offshore source and attenuation characterizations, local site effects, and structure-foundation-soil interactions that may be exceptional to the offshore environment are discussed.
Session 6: Discussion And Replies, Multiple Authors
Session 6: Discussion And Replies, Multiple Authors
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
No abstract provided.
Seismic Analysis As A Tool In The Design Of Two Earth Dams, A. Yziquel, M. Lino, G. Post, B. Tardieu
Seismic Analysis As A Tool In The Design Of Two Earth Dams, A. Yziquel, M. Lino, G. Post, B. Tardieu
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Two dynamic analysis studies of embankment dams are described. One dam is 43m high on alluvium, the other is 140m high on a rock foundation in a highly seismic area. The main emphasis is on the practical nature of the analytical methods and their value as design tools. The earthquake design features of both projects are described and the closing paragraphs attempt to draw attention to the main points to be considered when running an earthquake analysis of earth dams.
Seismic Analysis Of Spinney Mountain Dam, J. V. Williamson, M. E. Shaffer
Seismic Analysis Of Spinney Mountain Dam, J. V. Williamson, M. E. Shaffer
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The Spinney Mountain Dam, now under construction in central Colorado, is a zoned earth embankment with a maximum height of 95 feet above foundation. Detailed geological investigations revealed rejuvenated sediments of nearby older faults, which have undergone tectonic movement within the past 13,000 to 30,000 years and hence are considered capable. Studies indicate the largest earthquake expected on the controlling fault would have a Richter Magnitude of about 6.2, implying peak ground accelerations at the site of about 0.6g and a 15-second duration of strong motion. Displacement on a branch of the main capable fault during such an event is …
Longitudinal Seismic Behavior Of Earth Dams, A. M. Abdei-Ghaffar
Longitudinal Seismic Behavior Of Earth Dams, A. M. Abdei-Ghaffar
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Earthquake-induced vibration in earth darns in a direction parallel to the darn axis is studied using analytical elastic models. The non-homogeneity of the darn materials is taken into account by assuming specific variations of the elastic moduli along the depth due to the confining pressure. Based on the models, a rational procedure is developed to estimate dynamic stresses and strains (both shear and normal) and corresponding elastic moduli and damping factors for earth darns from their hysteretic responses to real earthquakes, utilizing the hysteresis loops from the crest and base records. This leads to a study of the variation of …
Effective Stress Analyses Of Seismic Stability, E. Kavazanjian Jr., J. L. Chameau
Effective Stress Analyses Of Seismic Stability, E. Kavazanjian Jr., J. L. Chameau
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The factors involved in performing effective stress analysis of seismic stability problems are examined. The advantages of using a stochastic model for pore pressure generation are discussed. A simplified analysis of a hypothetical case is outlined to illustrate the factors involved in performing effective stress stability analysis.
Estimation Of Displacements Of Rockfill Dams Due To Seismic Shaking, J. L. Vonthun, C. W. Harris
Estimation Of Displacements Of Rockfill Dams Due To Seismic Shaking, J. L. Vonthun, C. W. Harris
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
A computer code for estimation of displacement of sliding surfaces during dynamic loading is discussed. The procedure allows selective incorporation of the effects of horizontal and vertical inertial forces, excess pore pressure development, hydrodynamic forces, shear strength reduction, and dilation. The relative effect of these parameters on the computed displacements can be readily determined for alternative design layouts or material behavior assumptions.
Seismic Deformation Of Dams By Correlative Methods, Y. K. Lin, K. V. Rodda, C. W. Perry, D. K. Gill
Seismic Deformation Of Dams By Correlative Methods, Y. K. Lin, K. V. Rodda, C. W. Perry, D. K. Gill
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Analyses are presented of the anticipated earthquake performance of three generally similar earth dams, situated in a seismically active area of northern California. The series of analyses illustrates a cost-effective approach which involved full-scale finite element analyses of one dam, and the use of limited dynamic analysis techniques and correlations to evaluate the other two. The simplified techniques were applied only after testing them against the finite element analyses, information is also presented on how the results of simplified and full-scale dynamic analysis procedures correlate.
On The Dynamic Stability Of Block Sliding On Rock Slopes, Wang Sijing, Zhan Juming
On The Dynamic Stability Of Block Sliding On Rock Slopes, Wang Sijing, Zhan Juming
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
This paper deals with the dynamic analysis of block sliding on rock slope along plane surfaces, such as joints, bedding planes and faults. According to the results obtained in the shaking tests the dynamic friction along a sliding surface is dependent on the velocity of relative motion, and can be determined by using the proposed method of test. On the basis of conducted experiments a differential equation was established. The integration of the dynamics equation by numerical method provides a basis for evaluation of slope stability in terms of critical displacement and dynamic instability.
On The Use Of Nonlinear Soil Models, Albert T. F. Chen
On The Use Of Nonlinear Soil Models, Albert T. F. Chen
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The basic definitions of, and the differences between, currently available soil models are reviewed. These models are applied to site response analyses where two depths and two levels of base input motion are considered. Computational results are presented and compared with regard to the effects of using different soil models on computed site response. Other implications resulting from the choice of soil model for seismic response analysis are also discussed.
Permanent Deformation Of Earth Dams Under Earthquakes, William Y. J. Shieh, Rodney J. Huang
Permanent Deformation Of Earth Dams Under Earthquakes, William Y. J. Shieh, Rodney J. Huang
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Assessment of dam embankment deformation by various methods such as those proposed by Newmark, Ambraseys and Seed was reviewed herewith. A simple method based on dynamic response spectrum analyses by step-by-step integration technique is proposed for independent permanent deformation evaluation. The proposed method assumes that failure occurs on a well-defined slip surface and that the material behaves elastically at stress level below failure but develops a perfectly plastic behavior above the yield acceleration. The results of the proposed method were compared with those obtained from other method for actual examples. Favorable agreement on the analytical results was achieved.
Analysis Of Dynamic Shear Strain Distributed In Three Dimensional Earthdam Models, T. Ohmachi
Analysis Of Dynamic Shear Strain Distributed In Three Dimensional Earthdam Models, T. Ohmachi
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Dynamic shear strain distribution have been evaluated and illustrated for three dimensional earthdam models. The analysis method applied here is a simplified finite element method, which has proved to give vibration modes of an earthdam to a satisfactory level of accuracy by involving a smaller number of degrees of freedom. Mass and stiffness matrices of a dam have been formulated for two types of the shear modulus distribution, one uniform and the other linearly increasing with depth below the crest. Both magnitude and location of the maximum shear strain have been discussed in relation to topography of dam sites.
A Simplified Procedure For Evaluating Maximum Response Of Soil Layer During An Earthquake, Fu Shengcong, Jiang Jingbei
A Simplified Procedure For Evaluating Maximum Response Of Soil Layer During An Earthquake, Fu Shengcong, Jiang Jingbei
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
In this paper, the horizontally stratified soil layers are simplified as a shearing type multidegree of freedom linear system. The transfer function of the system is determined in accordance with the statistic analysis of the result from the mode superposition method of soil layer earthquake response. By referring to the method of finding the extreme value in probabilistic theory, a response spectrum corresponding to the power spectral density of soil layers is given. At the same time, distributions of maximum response values of acceleration, displacement, shearing strain and shearing stress of the soil layers along the depth are given according …
Session 7: Discussion And Replies, Multiple Authors
Session 7: Discussion And Replies, Multiple Authors
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
No abstract provided.