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1991

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Articles 871 - 900 of 1363

Full-Text Articles in Engineering

Structural Damage In A Populated Area Due To An Active Fault, N. Kalteziotis, N. Sabatakakis, G. Koukis, H. Zervogiannis, G. Tsiambaos Mar 1991

Structural Damage In A Populated Area Due To An Active Fault, N. Kalteziotis, N. Sabatakakis, G. Koukis, H. Zervogiannis, G. Tsiambaos

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

The city of Patras was struck in August 1989 by a shallow earthquake of MS= 4.8 which caused a surface rupture and serious structural damage to several buildings located in a narrow elongated zone. A detailed investigation programme was carried out including geological mapping, drilling of boreholes, in situ and laboratory testing and monitoring of horizontal and vertical movements. It was found that the surface rupture, about 1500 m long, was closely related with the reactivation of a preexisting normal fault. The structural damage of buildings was found to be limited mainly in a narrow zone 50 m …

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Validation Of A Piles Dynamic Analysis Computer Code Through In Situ Tests, R. Bonaz, A. Pecker, T. Duroy, M. Ralljaona, J. P. Touret Mar 1991

Validation Of A Piles Dynamic Analysis Computer Code Through In Situ Tests, R. Bonaz, A. Pecker, T. Duroy, M. Ralljaona, J. P. Touret

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

In order to qualify the CLAPIFOU code, which computes the dynamic response of a pile foundation subjected to earthquake or harmonic forces, a test campaign was carried out on piles, to full scale, on pile groups of 2 x 1 piles and 2 x 3 piles on the Plancoet site. The purpose of the study is to compare the results of the experiments and the digital simulations with the computer code. The comparison is good but confirms the need for a good knowledge of the soil's characteristics.

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Aspects Of Seismic Analysis And Design Of Rockfill Dams, George Gazetas, Panos Dakoulas Mar 1991

Aspects Of Seismic Analysis And Design Of Rockfill Dams, George Gazetas, Panos Dakoulas

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

Theoretical methods for estimating the dynamic response and predicting the performance of modern rockfill dams subjected to strong earthquake shaking are reviewed. The focus is on methods accounting for nonlinear material behavior, for 3-Dimensional canyon geometry, and asynchronous base excitation. It is shown that both strong nonlinearities and lack of coherence in the seismic excitation tend to reduce the magnitude of the deleterious "whip-lash" effect computed for tall dams built in rigid-wall narrow canyons. Particular emphasis is accorded to Concrete-Faced Rockfill dams and a case study involving an actually designed dam in a narrow canyon points to some potential problems …

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Classification Of Analysis Methods For Dynamic Soil-Structure Interaction, John P. Wolf Mar 1991

Classification Of Analysis Methods For Dynamic Soil-Structure Interaction, John P. Wolf

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

The various methods to perform soil-structure-interaction analysis are classified. The first classification uses as criterion the behavior (linear or nonlinear) of the structure and of the unbounded soil. The second classification distinguishes between the direct method and the substructure method, which do not necessarily lead to identical results. Within each method, however, the various procedures are mathematically equivalent. In the substructure method the dynamic stiffness representing the interaction forces of the unbounded soil is determined based on the boundary element method in the time or frequency domain. In the latter case various so-called realizations in the time domain are distinguished …

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State Of The Art Papers: Discussion And Replies, Tzou-Shin Ueng Mar 1991

State Of The Art Papers: Discussion And Replies, Tzou-Shin Ueng

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

No abstract provided.

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Seismic Design Of Earth Retaining Structures, R. V. Whitman Mar 1991

Seismic Design Of Earth Retaining Structures, R. V. Whitman

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

Recent experiments, field observations and theoretical numerical studies are summarized: Where the simple conditions assumed by the Mononobe-Okabe theory are reproduced. ln tests, predictions and observations agree well. However, a retaining structure and surrounding soil are a complex dynamic system and behavior is far from simple. Emphasis has shifted somewhat away from dynamic stresses toward evaluation of residual displacements. With a good understanding of actual behavior, traditional methods may still be used except for large and unusual structures. The largest unknowns concern the behavior of cohesive soils and moderately dense to dense saturated sands.

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Preface, Shamsher Prakash Mar 1991

Preface, Shamsher Prakash

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

No abstract provided.

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Welcoming Remarks, Joseph E. Minor Mar 1991

Welcoming Remarks, Joseph E. Minor

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

No abstract provided.

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Pictures And Participants, Multiple Members Mar 1991

Pictures And Participants, Multiple Members

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

No abstract provided.

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Representative Earthquake Features In The New Madrid Seismic Zone As Seen By Participants In The March 15-17, 1991, Field Trip, David Stewart Mar 1991

Representative Earthquake Features In The New Madrid Seismic Zone As Seen By Participants In The March 15-17, 1991, Field Trip, David Stewart

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

No abstract provided.

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Application Of The Elastoplastic-Viscoplastic Bounding Surface Model To Cyclic Loading, Victor N. Kaliakin Mar 1991

Application Of The Elastoplastic-Viscoplastic Bounding Surface Model To Cyclic Loading, Victor N. Kaliakin

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

The predictive capabilities of the elastoplastic-viscoplastic bonding surface mode, with emphasis response of cohesive soils subjected to cyclic loading, are discussed herein. This model, which represents a generalized three-dimensional constitutive formulation for isotropic cohesive soils, is developed within the framework coupled elastoplasticity-viscoplasticity and critical state soil mechanics.

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Behavior Of Geotextile Reinforced Soil Under Cyclic Loading, G. Venkatappa Rao, G. P. Singh, K. K. Gupta Mar 1991

Behavior Of Geotextile Reinforced Soil Under Cyclic Loading, G. Venkatappa Rao, G. P. Singh, K. K. Gupta

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

The vast potential of geotextiles for separation (reinforcement in pavements and rail roads is yet to be fully exploited in India, despite the initial successful trials. This is partly due to the lack of sufficient test data on the behavior under repetitive loading of indigenous geotextiles. This paper reports typical triaxial test results on reinforced and unreinforced specimens before and after cyclic loading. The reinforcement used is a needle punched polypropylene geotextile manufactured in India. The results reported include strength before and after cyclic loading (cyclic loading under both drained and undrained conditions), modulus of resilience and plastic strain. Limited …

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Cyclic Undrained Behavior Of An Undisturbed Gravel For Aseismic Design Of A Bridge Foundation, Fumio Tatsuoka, Shin-Lchi Yamada, Katsuhiko Yamada, Masahiko Yasuda, Susumu Manabe Mar 1991

Cyclic Undrained Behavior Of An Undisturbed Gravel For Aseismic Design Of A Bridge Foundation, Fumio Tatsuoka, Shin-Lchi Yamada, Katsuhiko Yamada, Masahiko Yasuda, Susumu Manabe

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

For the aseismic design of a pier foundation constructed on a lightly cemented dense gravel deposit of a 3,910m-long suspension bridge, cyclic and monotonic undrained triaxial tests were performed on undisturbed specimens with a diameter of 30cm taken from the deposit under a sea depth of about 55m. Using the results of the cyclic undrained triaxial tests together with irregular cyclic stresses evaluated for the design earthquake motion by a dynamic FEM analysis, maximum strains in the gravel deposit were obtained by the cumulative damage concept. The strain values thus estimated indicated a sufficiently high degree of seismic stability of …

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Cyclic Undrained Behavior Of Saturated Sand Under Monotonic Loading, Hiroshi Matsuzawa, Masahiro Sugimura Mar 1991

Cyclic Undrained Behavior Of Saturated Sand Under Monotonic Loading, Hiroshi Matsuzawa, Masahiro Sugimura

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

In order to investigate undrained behavior of saturated sand, three types of undrained triaxial tests were performed for saturated Toyoura sand, i.e., cyclic loading test with (DTU-test) and without (DU-test) constant initial shear stress and tests in which constant rate axial strain and cyclic axial stress were applied to a specimen simultaneously (DCU-test). In DCU-tests, three types of failure were observed, i.e.; 1) perfectly liquefied in the case of relatively loose sand, 2) initially liquefied, but shear failure was induced after strength recovery for succeeding loading in the case of relatively dense sand, and 3) shear failure was induced without …

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Cyclic Undrained Tests Along Constant Axial Stress On Hollow Cylinder, O. Hameury, T. Doanh Mar 1991

Cyclic Undrained Tests Along Constant Axial Stress On Hollow Cylinder, O. Hameury, T. Doanh

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

Cyclic hollow cylinder tests have been performed on sand and clay under undrained conditions. In order to point out the effects of the rotation of principal axes, a constant axial stress is maintained during the application of torsional shear. On this stress path, the behavior of the two materials is studied in terms of stress-strain relationship, pore pressure, failure criterion and also rotation of strain principal axes.

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Deformation Of Sand Under Cyclic Simple Shear Loading, Chung-Jung Lee Mar 1991

Deformation Of Sand Under Cyclic Simple Shear Loading, Chung-Jung Lee

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

The deformation behavior of sand under simple shear loading was studied. The relation between the shear stress ratio and fabric factor, and the relationship between the fabric and dilatancy rate of a sand were developed. Thus the stress-dilatancy relation for sand was derived. Adopting the concept that the volumetric changes of the sample induced by the cyclic shear stress were compensated by the volumetric changes due to vertical stress changes in the constant volume simple shear tests, the relation of shear stress ratio and vertical stress change was derived.

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Degradation Of Saturated Clays After Cyclic Loading, Tamotsu Matsui, Mohamed A. Bahr, Nobuharu Abe Mar 1991

Degradation Of Saturated Clays After Cyclic Loading, Tamotsu Matsui, Mohamed A. Bahr, Nobuharu Abe

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

This paper presents a part from a series of tests performed to evaluate the static shear behavior of normally consolidated and over-consolidated clays after cyclic loading effect. The results demonstrated that the static undrained stress-strain behavior of these types of clays was affected by their relative stiffness. Based on the equivalent over-consolidation hypothesis and the experimental results it was able to construct the shear characteristics degradation relationships for the normally consolidated clays. The predicted results were compared with the measured test data and their well agreement was confirmed.

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Development Of Shear Modulus Reduction Curves Based On Lotung Downhole Ground Motion Data, C.-Y. Chang, Y. K. Tang, C. M. Mok, H. T. Tang, M. S. Power, J. C. Stepp Mar 1991

Development Of Shear Modulus Reduction Curves Based On Lotung Downhole Ground Motion Data, C.-Y. Chang, Y. K. Tang, C. M. Mok, H. T. Tang, M. S. Power, J. C. Stepp

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

In this study, equivalent shear moduli (or shear-wave velocities) and their variations with shearing strain at the Lotung seismic experiment site were back-calculated from recorded downhole array ground motions. Ground motion data for various levels of shaking (peak ground surface accelerations ranging from 0.03g to 0.21g) recorded during seven earthquakes were used in the analyses. Results show that downhole array ground motion data can be used to infer in-situ dynamic soil properties over a wide strain range.

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Electrical Conductivity For Evaluating Fabric And Mechanical Behavior Of Granular Soils, Lien Kwei Chien, J. C. Li Mar 1991

Electrical Conductivity For Evaluating Fabric And Mechanical Behavior Of Granular Soils, Lien Kwei Chien, J. C. Li

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

In this study, an auto-compensation conductivity measurement system has been developed. This system is expected to offer a possible means for describing the granular soil fabric and mechanical behaviors. A series of cyclic triaxial compression, extension, and unloading tests with resistance measurement were performed. The correlation between granular soil friction angle φ, and vertical formation factor, Fv under maximum shear stress ratio has been studied. The test results have shown that the electrical conductivity could be used to evaluate the fabric behavior during the process of loading. The fabric ellipsoid function, which has been used to simulate the orientation …

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In Situ Torsional Cylindrical Shear Test-Laboratory Results, W. Henke, R. Henke Mar 1991

In Situ Torsional Cylindrical Shear Test-Laboratory Results, W. Henke, R. Henke

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

We present results from cyclic tests conducted in the laboratory using a prototype in situ cyclic torsional cylindrical shear geotechnical testing system. The system is intended to advance our ability to design critical systems to resist earthquakes by improving our ability to analytically predict the behavior of soil-structure-equipment systems during earthquakes. It is to do so by providing, more reliably than we feel is now possible, estimates of the in situ cyclic shear stress vs strain characteristics needed by refined earthquake analyses. These characteristics include 1) resistances to initial liquefaction, cyclic degradation, and large cyclic deformations, and 2) undegraded, nonlinear, …

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Lnsitu Measurement Of Damping Of Soils, W. P. Stewart, R. G. Campanella Mar 1991

Lnsitu Measurement Of Damping Of Soils, W. P. Stewart, R. G. Campanella

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

The Seismic Cone Penetration Test (SCPT) has been shown to give reasonable results for insitu measurements of shear wave velocity, and this paper extends this work to include measurements of damping. The relevant equations of motion are described, factors affecting amplitude decay are discussed, and the nature of damping is summarized. Consideration is given to some of the practical aspects of pre-processing of signals. Three methods of damping calculation are presented. The first two, attenuation coefficient and modified SHAKE methods, require the application of amplitude corrections, which is not straight-forward, give variable results, and indicate negative damping in a clayey …

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Lumped Parameters In Permanent Displacement, H. V. Phuong Truong Mar 1991

Lumped Parameters In Permanent Displacement, H. V. Phuong Truong

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

New dynamic spring and damping values, which are dependent on the frequency, have been introduced into calculations of horizontal permanent displacement. The new dynamic damping value, which is inversely proportional to the circular frequency, has the same form as the material damping, while the new value of stiffness increases with increase in circular frequency. Similar methods can be used to obtain new dynamic spring and damping values for other modes of vibrations such as vertical, rocking and torsional. An analytical treatment of the coupled rocking and sliding modes is presented which considers horizontal and vertical Coulomb friction forces, two-layered soil …

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Mechanical Properties Of Cemented Sands Based On Inter-Particle Contact Behavior, Anil Misra, Ching S. Chang Mar 1991

Mechanical Properties Of Cemented Sands Based On Inter-Particle Contact Behavior, Anil Misra, Ching S. Chang

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

The mechanical properties of cemented sands are modelled using a micromechanical approach. The derived model accounts for the packing structure, the particle properties and the contact properties.

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Modelling The Deformation Of Sand During Cyclic Rotation Of Principal Stress Directions, Marte Gutierrez, Kenji Ishihara, Ikuo Towhata Mar 1991

Modelling The Deformation Of Sand During Cyclic Rotation Of Principal Stress Directions, Marte Gutierrez, Kenji Ishihara, Ikuo Towhata

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

The paper presents an elastoplastic constitutive model for the deformation of sand during cyclic rotation of principal stress directions. The model employs a plastic potential theory that allows for the dependency of flow on the stress increment direction and a stress-dilatancy relation incorporating the effects of noncoaxiality. The continuous plastic deformation of sand during principal stress rotation at constant shear stress level is allowed for in the model by using a small elastic area in the stress space. The effects of cyclic stress history is modelled by using discrete surfaces of equal hardening modulus which are allowed to move with …

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Presentation Of The Porewater Pressure Buildup Using Moroto's And State Parameter, Predrag Kvasnička, Tomislav Lvšić Mar 1991

Presentation Of The Porewater Pressure Buildup Using Moroto's And State Parameter, Predrag Kvasnička, Tomislav Lvšić

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

In this paper it is attempted to generate the rise of pore water pressures in undrained strain controlled cyclic triaxial tests for various densities (void ratios), confining pressures and strain amplitudes. The results of cyclic triaxial tests on one type of standard Yugoslav sand are presented. Introducing the Moroto's parameter based on cumulative shear work normalized with confining pressure (Moroto, 1976) and a state parameter defined as a distance between initial void ratio and the steady state line (Been and Jefferies, 1985) the band of the results is narrowed and a single curve for representing the pore water pressure buildup …

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Soils Parameters And Constitutive Relations Under Multiaxial Cyclic Loading, M. Reza Salami Mar 1991

Soils Parameters And Constitutive Relations Under Multiaxial Cyclic Loading, M. Reza Salami

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

A generalized constitutive model based on the theory of plasticity is proposed and utilized to characterize stress-deformation behavior of soils and geological materials under complex and cyclic multiaxial loadings. It allows for factors such as hardenings, volume changes, stress paths, cohesive and tensile strengths and variation of yield behavior with mean pressure. It is applied to characterize behavior of soils, concrete and rocks. The Constants for the model are determined from series of available laboratory tests conducted under different initial confinements, cyclic hydrostatic preloading and stress paths obtained by using multiaxial and cylindrical triaxial testing devices. The model is verified …

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Stiffness And Damping Of Sands In Torsion Shear, Supot Teachavorasinskun, Hiroyuki Kato, Satoru Shibuya, Noriyuki Horii, Fumio Tatsuoka Mar 1991

Stiffness And Damping Of Sands In Torsion Shear, Supot Teachavorasinskun, Hiroyuki Kato, Satoru Shibuya, Noriyuki Horii, Fumio Tatsuoka

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

A laboratory investigation was carried out into stiffness and damping of sands as sheared in a torsional shear apparatus. In the drained monotonic and cyclic loading tests, a particular care was taken of the small strain measurements in which the secant stiffness was measured over a wide range of shear strain from about 10-6 to 10-2. Despite the marked differences in the grain size and the sample preparation method among the sands, a fairly good coincidence of the secant stiffness was seen, in common, in the range of shear strain less than about 1 x 10-5 …

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The Dynamic Properties Of Carbonate Sands From Seabed, Du Jian, Wu Xiaofeng, Zhu Longgen Mar 1991

The Dynamic Properties Of Carbonate Sands From Seabed, Du Jian, Wu Xiaofeng, Zhu Longgen

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

Four kind of carbonate sands from offshore seabed together with LB sand of U.K and Fujian sand of China were tested with the Resonant Column method. The results show that the stress strain relationship in the condition of small strain can be represented with the hyperbolic model. The modulus is less than that of general sand. The cementing strength between particles of carbonate sands is weak. The breakage of particles is easy after disturbed and the density, therefore, will be increased. These properties should be further studied for engineering purpose.

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The Effect Of Frequency Of Cyclic Loading On Earth Structures And Foundation Soils, Daniel E. Normandeau, Thomas F. Zimmie Mar 1991

The Effect Of Frequency Of Cyclic Loading On Earth Structures And Foundation Soils, Daniel E. Normandeau, Thomas F. Zimmie

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

Earth dams, earth embankments, slopes, and certain foundation soils are subject to cyclic loading with an initial locked-in static shear stress due to earthquakes, blasting operations, and in some cases machine vibrations. In order to investigate the effect of the frequency of the applied cyclic loading, thirty-one Norwegian Geotechnical Institute Direct Simple Shear (NGI-DSS) tests were run. Frequencies for the applied cyclic loading of 0.2 Hz, 0.05 Hz, and 0.025 Hz were used throughout this investigation. San Fernando Sandy Silt (SFSS), from the Lower San Fernando Dam which failed in 1971, was the material tested in this study. This investigation …

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Verification By Comparison Between Static And Dynamic Engineering Soil Parameters Evaluated By Means Of Box Tests, Jan Bencat Mar 1991

Verification By Comparison Between Static And Dynamic Engineering Soil Parameters Evaluated By Means Of Box Tests, Jan Bencat

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

A conventional track structure system consists of rails, ties, ballast, subballast and subgrade. To design a track on the basis of live load response and permanent settlement, it is necessary to have knowledge of dynamic stresses in the foundation layers of the track. It needs to determine the material properties and thus, the dynamic and permanent deformation response of the track structure. This paper gives results of the experimental measurements of static and dynamic engineering soil parameters evaluated by means of box tests, Bencat 1989.

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