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1995

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Articles 301 - 330 of 442

Full-Text Articles in Civil and Environmental Engineering

Organizing Committee Meeting: Agenda And Minutes, Multiple People Apr 1995

Organizing Committee Meeting: Agenda And Minutes, Multiple People

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

No abstract provided.

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Dynamic Geotechnical Comparative Testing Capability, W. Henke, R. Henke Apr 1995

Dynamic Geotechnical Comparative Testing Capability, W. Henke, R. Henke

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

A concept and preliminary design are presented for a special testing capability to be added to an existing large laboratory geotechnical testing chamber. The modified chamber is intended to allow, through comparative testing, the reasonably rigorous evaluation of methods for providing detailed information, for soil deposits, on in situ undegraded nonlinear inelastic shear stress vs strain characteristics needed for dynamic geotechnical earthquake engineering analyses. Basically, the added capability is to be a large resonant column-like torsional testing system that tests the entire chamber sample and allows access to the center of the sample for the testing of the method to …

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High Pressure Cyclic Triaxial Tests, Jianren Wang, Clay E. Sams, John D. Lawrence, Harry Johnson Apr 1995

High Pressure Cyclic Triaxial Tests, Jianren Wang, Clay E. Sams, John D. Lawrence, Harry Johnson

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

Shear modulus and damping from high pressure (up to 500 psi) cyclic triaxial tests of soils are presented. The test results are compared with published models where low confining pressures were used. The apparatus and test setup for the high pressure tests are also discussed.

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Study On Cyclic Shear Strength Of Soils From Different Methods, Chi-Tso Chang, Jin-Hung Hwang Apr 1995

Study On Cyclic Shear Strength Of Soils From Different Methods, Chi-Tso Chang, Jin-Hung Hwang

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

This paper compares the cyclic strengths of soils from different methods using intensive investigations at a recent alluvial site on the southwest Taiwan. Generally speaking, the cyclic shear strengths deduced from different methods exhibit the following trend: Block sample > Tube sample ↔ SPT -N (Standard Penetration Test) method > seismic Vs method > CPT-qc (Cone Penetration Test) method.

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High Strain Rate Testing Of Unsaturated Sands Using A Split-Hopkinson Pressure Bar, G. E. Veyera, C. A. Ross Apr 1995

High Strain Rate Testing Of Unsaturated Sands Using A Split-Hopkinson Pressure Bar, G. E. Veyera, C. A. Ross

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

High strain rate tests were conducted on specimens of three different sands at saturations varying from dry to 100% using a Split-Hopkinson Pressure Bar. Compacted specimens were subjected to undrained uniaxial confined compression at approximate strain rates of 1000/s and 2000/s by an approximate square wave input of 225 MPa with a pulse length of 250 µs. The stress-strain curves show an initially steep portion which appears to be strain rate independent. Beyond this, slopes are about the same up to the lock-up strain, an abrupt change in slope, indicating an increase in stiffness. The effect of increasing saturation is …

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Soil Damping And Its Use In Dynamic Analyses, A. K. Ashmawy, R. Salgado, S. Guha, V. P. Drnevich Apr 1995

Soil Damping And Its Use In Dynamic Analyses, A. K. Ashmawy, R. Salgado, S. Guha, V. P. Drnevich

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

Soil response under dynamic loading has been modeled using linear-viscoelasticity for many decades. The definitions of various damping-related quantities are reviewed and the implications of their use in the analysis of continuous masses are given. The selection of an equivalent damping ratio as a parameter for modeling damping in most geotechnical applications is discussed together with the assumptions underlying the selection procedure. The techniques for damping determination using laboratory testing are summarized, emphasizing the influence that factors such as apparatus type, loading path, rate of loading, and strain level have on the measurement. Disturbance effects in samples recovered from the …

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Stress Dependence Of Sand Stiffness, D. C. F. Lo Presti, M. Jamiolkowski, O. Pallara, V. Pisciotta, S. Ture Apr 1995

Stress Dependence Of Sand Stiffness, D. C. F. Lo Presti, M. Jamiolkowski, O. Pallara, V. Pisciotta, S. Ture

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

The stress dependence of the Young's modulus of two sands was studied with a computer controlled triaxial apparatus, capable of giving reliable measurements of the stiffness even at very small strains ≈ 0.001 %. It was therefore possible to determine the Young's modulus of the sands for a wide strain range, from very small to very large, up to 20 %. The tested sands were: a uniform fine quartz sand not containing fines (Toyoura sand- TOS), and a well graded coarse to medium carbonatic, crushable sand containing about 2% of fines (Quiou sand - QS). The specimens were reconstituted in …

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Evaluation Of Bender Elements For Use With Coarse-Grained Soils, S. Nazarian, S. S. Baig Apr 1995

Evaluation Of Bender Elements For Use With Coarse-Grained Soils, S. Nazarian, S. S. Baig

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

The feasibility of using piezo-ceramic bender elements for measuring shear modulus of coarse materials has been reported. If was found that moduli obtained from bender element are repeatable. The results in most cases compare favorably with those obtained by resonant column.

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Static Shear And Liquefaction Potential Of Sand, Chung-Jung Lee Apr 1995

Static Shear And Liquefaction Potential Of Sand, Chung-Jung Lee

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

The state parameter, which describes the initial state of sand before shearing, combining with the concepts of critical stress ratio line and phase transform line are used to assess the characteristics of sand during shearing. The state parameter of each tested sample is determined after the steady state line is constructed, and then relations of characteristics of the cyclic deformation behavior and the state parameter of sand are discussed. The value of the lowest point, Sup1 on the CSR line in the p’ – q plot is related to ec for a specific sand. Once the stress path of …

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Effects Of Earthquake Induced Rates Of Shearing On Residual Soil Strength, Achilleas N. Parathiras Apr 1995

Effects Of Earthquake Induced Rates Of Shearing On Residual Soil Strength, Achilleas N. Parathiras

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

The behavior of soils when sheared at high rates of displacement, such as those which may be induced by earthquakes, has been investigated by means of the ring shear apparatus. Plastic and non-plastic soils were tested normally and over-consolidated, remoulded and dry, submerged and non-submerged in water, in order to assess the effect which the stress history and the presence of water in the matrix and the environment of the sample have on its response upon fast shearing. It was concluded that two types of behavior exist which depend on the nature of each sample and the presence of water …

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Effect Of Fines Content On The Cyclic Undrained Behavior Of Sand, D. Erten, M. H. Maher Apr 1995

Effect Of Fines Content On The Cyclic Undrained Behavior Of Sand, D. Erten, M. H. Maher

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

The influence of fines on the liquefaction potential of sandy soils has been studied by conducting isotropically consolidated stress controlled triaxial tests. Experimental results are compared with predictions using the theory developed by Nasser and Shokooh which is based on energy considerations. The theory determines the excess pore water pressure in terms of the number of cycles N, the dimensionless shear stress amplitude, and the initial and minimum values of the void ratio. The comparisons show good agreement between experimental data and model predictions for the pore water generation under cyclic loading for both loose and medium sands and medium …

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Static And Dynamic Strength Properties Of A Fiber-Reinforced Compacted Cohesive Soil, R. M. Ai Wahab, G. B. Heckel Apr 1995

Static And Dynamic Strength Properties Of A Fiber-Reinforced Compacted Cohesive Soil, R. M. Ai Wahab, G. B. Heckel

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

Soil reinforcement with randomly oriented, individual synthetic fibers has been applied to laboratory specimens of a compacted cohesive soil. Fiber contents of up to 1.0% by soil dry weight were mixed with the soil. Data from unconfined compression (static) testing and resilient modulus (dynamic) testing have been presented. Experimental work showed that the fibers increased the soil unconfined compressive strength, ductility, toughness, static and dynamic energy absorption capacities, the resilient strain and the number of cycles to failure. The soil resilient modulus and the permanent strain both decreased with the increase in fiber content.

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Soil-Pile-Structure During Liquefaction On Centrifuge, Masayoshi Sato, Yasuhiro Shamoto, Jian-Min Zhang Apr 1995

Soil-Pile-Structure During Liquefaction On Centrifuge, Masayoshi Sato, Yasuhiro Shamoto, Jian-Min Zhang

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

Larger scale dynamic centrifuge modeling has been used to examine the behavior of a soilpile-structure system during earthquake-induced liquefaction. The model consisting of a 3 x 3-pile supported structure and a saturated sand deposit was constructed in a laminar container with the inside dimensions of 74-cm length, 50-cm height and 34-cm width. Test results show that liquefaction occurred only within a finite zone in the saturated sand deposit subjected to a strong input shaking that corresponds to a maximum earthquake acceleration of 0.3 g induced probably in actual ground, which agrees well with the results of earthquake damage investigation; moreover, …

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Earthquake Input Motions For Physical Model Tests, Gregg L. Fiegel, I. M. Ldriss, Bruce L. Kutter Apr 1995

Earthquake Input Motions For Physical Model Tests, Gregg L. Fiegel, I. M. Ldriss, Bruce L. Kutter

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

The results from several dynamic centrifuge experiments are presented in this paper; the experiments were performed as part of a study to assess the influence of local site conditions on earthquake ground motions. Medium dense dry sand and saturated soft clay models were subjected to the accelerogram recorded at Santa Cruz during the 1989 Loma Prieta Earthquake. Scaled versions of the input motion were used to shake the soil models; in addition, different time steps were used in order to study the effects of frequency content of the input motion. The results confirm that the characteristics of the input motion …

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Dynamic Deformation Characteristics Of Rockfill Materials From Laboratory Test, In-Situ Test And Earthquake Motion Analysis, Tomoya Lwashita, Nario Yasuda, Akira Nakamura, Osamu Takeda Apr 1995

Dynamic Deformation Characteristics Of Rockfill Materials From Laboratory Test, In-Situ Test And Earthquake Motion Analysis, Tomoya Lwashita, Nario Yasuda, Akira Nakamura, Osamu Takeda

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

On dynamic analyses of rockfill dams, dynamic deformation characteristics of rockfill materials such as shear moduli and damping ratios must be known to make analysis more accurate. In this study, large-scale cyclic triaxial tests were carried out using rockfill materials of actual dams, and the results were compared with the dynamic deformation characteristics obtained by in-situ geophysical explorations and response analyses of earthquake motions observed at dams. Furthermore, the radiation damping ratio was estimated from response analyses and laboratory tests, and then the frequency and strain dependency characteristics of the radiation damping were evaluated.

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Microconcrete Subjected To Static And Dynamic Compression Loadings, Bassam Hwaija Apr 1995

Microconcrete Subjected To Static And Dynamic Compression Loadings, Bassam Hwaija

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

The object of our paper is to consider the influence of the particularly important factor, and to achieve a model describing the behavior of the microconcrete. The specimens have been loaded in rates ranging from 0.0001 to 800 (1/s). The results are discussed available in the literature.

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Dynamic Centrifuge Experiment On A Cantilever Retaining Wall, M. M. Dewoolkar, A. T. Stadler, S. N. Batiste, H. Y. Ko, R. Y. S. Pak Apr 1995

Dynamic Centrifuge Experiment On A Cantilever Retaining Wall, M. M. Dewoolkar, A. T. Stadler, S. N. Batiste, H. Y. Ko, R. Y. S. Pak

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

Seismic loads on a tall, cantilever retaining wall were studied using centrifuge modeling. An aluminum wall (55' prototype) retaining dry, cohesionless backfill was subjected to two successive dynamic events. The backfill surface was horizontal and even with the top of the wall. The input motion was supplied via a servo-controlled, electro-hydraulic shake table. The input motion was roughly sinusoidal with peak horizontal accelerations of approximately 0.2g and 0.4g for the first and second dynamic events, respectively. The input motion frequency was 1 hz at prototype scale. Lateral earth pressures on the wall, wall displacement, and accelerations of the wall and …

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Cycle Plate Load Tests On Reinforced Sand, Swami Saran, B. V. K. Lavania, R. K. Sharma Apr 1995

Cycle Plate Load Tests On Reinforced Sand, Swami Saran, B. V. K. Lavania, R. K. Sharma

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

This paper presents a set of results of laboratory scale model footing tests conducted to determine the cyclic load resistance of sand beds reinforced with horizontal sheets of geogrid. The test results indicate that the total settlement decreases and the bearing capacity increases, with the increase in size of reinforcements and number of layers. With the inclusion of reinforcing sheets, ·the coefficient of elastic uniform compression decreases slightly; but this decreased value is valid up to the increased bearing capacity of the reinforced sand bed. There is significant improvement in the damping capacity upon reinforcing the sand bed as indicated …

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Application Of Deep Compaction Techniques To Liquefaction Prevention, G. Armijo, P. Sola, C. Oteo Apr 1995

Application Of Deep Compaction Techniques To Liquefaction Prevention, G. Armijo, P. Sola, C. Oteo

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

This article analyzes the application of dynamic compaction, vibroflotation and vibroreplacement (stone columns) to liquefaction prevention. The ground types to which they can be applied, the depths that can be reached and the degree of improvement that can be obtained are all studied. Finally, and on the basis of the above, basic guidelines are given for the design of ground improvement with these techniques and for the aforementioned purpose.

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Liquefaction Damage Of Sandy And Volcanic Grounds In The 1993 Hokkaido Nansei-Oki Earthquake, S. Miura, K. Yagi, S. Kawamura Apr 1995

Liquefaction Damage Of Sandy And Volcanic Grounds In The 1993 Hokkaido Nansei-Oki Earthquake, S. Miura, K. Yagi, S. Kawamura

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

The 1993 Hokkaido Nansei-Oki Earthquake of magnitude 7.8 caused widespread and significant damage in south west area of Hokkaido, Japan. The soil liquefaction was induced at many locations, which resulted in considerable damage to structures, lifelines, and facilities. In order to evaluate their in-situ liquefaction strengths, the site investigation involved the conduct of standard penetration test (SPT) was performed at several key locations. A series of cyclic undrained triaxial tests was also carried out on soil samples taken from liquefied grounds. Test results showed that the mechanism of increase in the liquefaction strength due to the increase in relative density …

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Effect Of The Grain Size On The Energy Per Unit Volume At The Onset Of Liquefaction, J. Ludwig Figueroa, Adel S. Saada, Liqun Liang Apr 1995

Effect Of The Grain Size On The Energy Per Unit Volume At The Onset Of Liquefaction, J. Ludwig Figueroa, Adel S. Saada, Liqun Liang

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

Recent exploratory work by the authors indicated the feasibility of relating the development of the pore water pressure leading to liquefaction of soils subjected to earthquake loading to the amount of unit energy imparted to the soil during the dynamic motion. This research also showed that regardless of the mode of stress application, sinusoidal or random, the unit energy needed to initiate liquefaction is nearly constant for a given effective confining stress and a specific relative density, demonstrating that the unit energy is independent of the shear strain amplitude. Data obtained during torsional shear tests on a given soil made …

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Correlation Between Cpt Data And Dynamic Properties Of In Situ Frozen Samples, Y. Suzuki, K. Tokimatsu, Y. Taya, Y. Kubota Apr 1995

Correlation Between Cpt Data And Dynamic Properties Of In Situ Frozen Samples, Y. Suzuki, K. Tokimatsu, Y. Taya, Y. Kubota

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

Correlations between cone penetration resistance and liquefaction resistance of sandy soils are examined, based on high quality undisturbed samples obtained by the in situ freezing method. For this purpose, the CPT tests are conducted at six sites where in situ frozen sands with fines contents up to 30 % were sampled and their dynamic properties were determined in the laboratory. The comparison of the CPT data with the soil properties of the in situ frozen samples has shown that: (1) Robertson's soil classification chart performs well for sandy soils in Japan; (2) the CPT qt-value shows a good correlation with …

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Liquefaction Of The Alluvial Soils Of Bangladesh, M. A. Mollah Apr 1995

Liquefaction Of The Alluvial Soils Of Bangladesh, M. A. Mollah

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

In this paper, the potential of the often-saturated sandy soils that occur within the uppermost sub-surface stratigraphy across the Bangladesh plains to experience initial liquefaction due to seismically induced pore water pressure is evaluated. Bore hole logs from development projects were collected. Standard Penetration Test (SPT) values from the drill holes were utilized as the primary data and a widely practiced computational method was employed to estimate the liquefaction potential. The analysis of data indicated that the uppermost portion of the sandy soil layer within 20 m of the surface is loose and sensitive to liquefaction under the influence of …

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An Empirical Formula For Evaluation Of Buildings Settlements Due To Earthquake Liquefaction, Huishan Liu Apr 1995

An Empirical Formula For Evaluation Of Buildings Settlements Due To Earthquake Liquefaction, Huishan Liu

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

In this paper the liquefiable subsoils are divided into two groups: type of liquefiable supporting layer and type of liquefiable underlayer. Based on the observed subsidence data and general tendency got from finite element analysis, an empirical formula for evaluation of subsidences of type of liquefiable supporting layer is suggested. Several important factors' such as earthquake intensity' contact pressure at foundation bottom' and relative density of liquefiable soil are involved in this formula. So the formula seems credible to a certain extent.

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Prediction Of Settlements Of Soft Clay Caused By Earthquakes, Zhou Jian, K. Yasuhara Apr 1995

Prediction Of Settlements Of Soft Clay Caused By Earthquakes, Zhou Jian, K. Yasuhara

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

This paper develops an analytical method for the calculation of the earthquake-induced settlement of foundation by using Biot's type consolidation equation. In order to investigate the effectiveness of the proposed method, a comparison of the numerical result with the observed earthquake-induced settlement on the site at Sendai in Japan caused by the miyagioki earthquake in 1987 will be presented.

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Co-Reporter's Remarks — Session Iii, B. O. Skipp Apr 1995

Co-Reporter's Remarks — Session Iii, B. O. Skipp

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

No abstract provided.

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Discussions And Replies — Session Iii, Multiple Authors Apr 1995

Discussions And Replies — Session Iii, Multiple Authors

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

No abstract provided.

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A Unified Procedure For Earth Pressure Calculations, Ashok K. Chugh Apr 1995

A Unified Procedure For Earth Pressure Calculations, Ashok K. Chugh

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

A unified procedure for calculating active and passive earth pressures on retaining structures for static and seismic (pseudostatic) loading conditions is presented. The procedure is based on the limit equilibrium method, uses the method of slices, and satisfies complete statics. Necessary equations for a typical slice are presented and a solution scheme for solving them is discussed. A sample problem is included to indicate convenience of use of the proposed procedure and accuracy of results obtained. The results are in terms of magnitude, direction, and location of lateral thrust on the wall; however, distribution of earth pressure along the wall …

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Soil Investigation And Fvt Analysis In Hualien Lsst Ssi Research, T. Ueshima, K. Kudo, T. Kokusho, T. Okamoto, Y. Tanaka Apr 1995

Soil Investigation And Fvt Analysis In Hualien Lsst Ssi Research, T. Ueshima, K. Kudo, T. Kokusho, T. Okamoto, Y. Tanaka

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

An international joint research program, Large-Scale Seismic Test (LSST) Program at Hualien, Taiwan, is ongoing, where a large-scale model structure partly embedded in gravelly layer was constructed, in-depth site soil geotechnical investigation was performed at every one of four construction stages, that is, before excavation, after excavation before structure construction, after structure construction before backfill, and after backfill, forced vibration tests (FVTs) of the model structure before backfill (FVT-1) and after backfill (FVT-2) were performed, and seismic observation of the dynamic SSI (soil-structure interaction) system is underway. This paper describes the change of the shear wave velocity (Vs) accompanied by …

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Study Of Seismic Base Isolation Of Bridge Considering Soil Structure Interaction, S. K. Thakkar, Rajesh Maheshwari Apr 1995

Study Of Seismic Base Isolation Of Bridge Considering Soil Structure Interaction, S. K. Thakkar, Rajesh Maheshwari

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

In this paper, a comprehensive study of seismic response of base isolated bridge is made by varying different parameters such as soil stiffness, embedment depth, hydrodynamic pressure and earthquake response spectrum. The object is to determine effect of soil-structure interaction on seismic response when isolation by elastomeric bearing is provided between superstructure and substructure. Elastomeric bearing is seen to be effective in reducing seismic response of substructure on rocky site. The increase in embedment depth also causes reduction in bending moments and shear forces in the substructure. The use of elastomeric bearing in place of Rocker-Roller bearing is seen to …

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