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1991

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Articles 241 - 270 of 505

Full-Text Articles in Civil and Environmental Engineering

Performance Of Concrete Faced Earthdam To Loma Prieta Earthquake, Sukhmander Singh, Nick Pal Mar 1991

Performance Of Concrete Faced Earthdam To Loma Prieta Earthquake, Sukhmander Singh, Nick Pal

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

As a result of the shaking from the Loma Prieta Earthquake of 1989, the concrete lining of an earth embankment suffered cracking at numerous locations on its upstream side and developed in its bed lining, crater-like pot-holes ranging in size up to 10 ft. in diameter. Field investigation and preliminary studies indicated the differential dynamic vibrations of the earth embankment and the concrete lining to be the cause of the cracking, and the liquefaction of the underlying stratum below the bottom of the reservoir to be the cause of the pot-holes formed as a result of the pore pressure bursting …

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Source, Path And Site Effects On Loma Prieta Strong Motions, P. G. Somerville, N. F. Smith Mar 1991

Source, Path And Site Effects On Loma Prieta Strong Motions, P. G. Somerville, N. F. Smith

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

The amplitudes of strong ground motions from the Loma Prieta earthquake recorded in the San Francisco and Oakland areas exceeded the levels predicted by standard empirical attenuation relations. Preliminary analysis of accelerograms having known trigger times suggests that the elevation of ground motion amplitudes in the distance range of approximately 40 to 100 km was due to critical reflections from the base of the crust. These reflections were large and occurred at relatively close range because of the deep focal depth of the earthquake and the strong velocity gradient at the base of the crust, and were enhanced by rupture …

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System Identification And Seismic Performance Evaluation Of Earth Dams, H. S. Sayed, A. M. Abdel-Ghaffar, S. F. Masri Mar 1991

System Identification And Seismic Performance Evaluation Of Earth Dams, H. S. Sayed, A. M. Abdel-Ghaffar, S. F. Masri

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

A system identification technique is developed to provide dynamic properties of earth dams from their seismic records. The technique is utilized to assess the capabilities and limitation of analytical models in terms of dynamic nonlinear constitutive relationships as well as damping. The technique is based on the least square method using Gaussian hypothesis. Earth dams are modeled as a three-dimensional nonhomogeneous visco-elasto-plastic soil structure. The forward problem is solved using a Galerkin-Ritz formulation in which the solution is expanded using basis function, which is selected to be the eigenmodes. The spatial variation of the excitation is considered by using global …

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Performance Of A Hazardous Waste And Sanitary Landfill Subjected To Loma Prieta Earthquake, Hari D. Sharma, Harish K. Goyal Mar 1991

Performance Of A Hazardous Waste And Sanitary Landfill Subjected To Loma Prieta Earthquake, Hari D. Sharma, Harish K. Goyal

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

Loma Prieta Earthquake of October 17, 1989 caused severe damages in the San Francisco Bay Area. Field measurements made during the earthquake and analyses performed to date indicate that bedrock accelerations were amplified to 2 to 3 times in propagating through deep cohesive deposits. In view of this, the performance of a hazardous waste and sanitary landfill subjected to Loma Prieta Earthquake and founded on deep cohesive deposits was evaluated. Analyses indicate that the peak accelerations at the base of the refuse are slightly amplified in propagating through the refuse thicknesses of up to about 50 feet. For higher refuse …

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Testing Of Stressed State In The Structure-Base System Under Non-Stationary Dynamic Effects, Vyacheslav K. Musaev Mar 1991

Testing Of Stressed State In The Structure-Base System Under Non-Stationary Dynamic Effects, Vyacheslav K. Musaev

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

Some aspects of practical realization of the finite element method (FEM) are considered for solving a two-dimensional (plane) dynamic problem of the theory of elasticity and plasticity. The results of the numerical solution of some problems for dynamic effects are presented. The comparison with the results of other methods is made.

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Assessment Of Liquefaction Potential And Post-Liquefaction Behavior Of Earth Structures: Developments 1981-1991, W. D. Liam Finn Mar 1991

Assessment Of Liquefaction Potential And Post-Liquefaction Behavior Of Earth Structures: Developments 1981-1991, W. D. Liam Finn

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

Significant developments in procedures for evaluating liquefaction potential and the post-liquefaction behaviour of earth structures are reviewed for the period 1981-1991. Particular attention is paid to the re-valuation of the liquefaction induced slide in the San Fernando Dam following the 1971 earthquake. The findings of this study have had a major impact on engineering practice.

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Effects Of Soil-Structure Interaction For Structures Subjected To Earthquakes, A. S. Veletsos Mar 1991

Effects Of Soil-Structure Interaction For Structures Subjected To Earthquakes, A. S. Veletsos

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

An extended summary is presented of a state-of-the-art report on the subject matter. The report parallels one presented at the Fourth U. S. National Conference on Earthquake Engineering, in May 1990.

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Geotechnical Lessons Learned From Mexico And Other Recent Earthquakes, Emilio Rosenblueth, Efrain Ovando Mar 1991

Geotechnical Lessons Learned From Mexico And Other Recent Earthquakes, Emilio Rosenblueth, Efrain Ovando

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

This paper describes the most relevant effects of the September 1985 earthquakes on Mexico City. It discusses the results of recent exploration and research on regional geology, local site conditions and site response analyses, basic soil properties, and observation of actual behavior of soil-foundation-structure systems. The paper shows the impact of these investigations upon new - building code requirements, on general design practice and on the specialist's perception of earthquake behavior of Mexico City's subsoil. Recent earthquakes recorded in and around Mexico City have contributed insight into some of the unresolved questions left after the experience of 1985. Damaging earthquakes …

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Disclaimer, Shamsher Prakash Mar 1991

Disclaimer, Shamsher Prakash

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

No abstract provided.

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Conference Schedule, Multiple Authors Mar 1991

Conference Schedule, Multiple Authors

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

No abstract provided.

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Committees, Multiple Members Mar 1991

Committees, Multiple Members

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

No abstract provided.

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Banquet Speeches And Remarks, Shamsher Prakash, Shiming Wu, Kenji Akino, John T. Park, Joseph H. Senne, Jeanne L. Senne Mar 1991

Banquet Speeches And Remarks, Shamsher Prakash, Shiming Wu, Kenji Akino, John T. Park, Joseph H. Senne, Jeanne L. Senne

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

No abstract provided.

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Index, Multiple Authors Mar 1991

Index, Multiple Authors

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

No abstract provided.

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Author And Discussion Index, Multiple Authors Mar 1991

Author And Discussion Index, Multiple Authors

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

No abstract provided.

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Errata, Multiple Authors Mar 1991

Errata, Multiple Authors

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

No abstract provided.

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A Cyclic Shear-Volume Coupling And Pore Pressure Model For Sand, Peter M. Byrne Mar 1991

A Cyclic Shear-Volume Coupling And Pore Pressure Model For Sand, Peter M. Byrne

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

A two parameter incremental shear-volume coupling equation is presented for sand. The equation is based upon experimental data and gives predictions that are in excellent agreement with data over a range of relative densities and stress conditions. Empirical expressions for the two parameters based on incorporated in a simple shear pore pressure element model and the predictions of the model are compared with both saturated undrained cyclic strain and cyclic load tests. It is found that, provided a threshold strain is incorporated, the model predictions are in very good agreement with the laboratory data over a wide range of stress …

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A Cyclic Triaxial Facility For Loading A Silty Clay, Matthew Raybould Mar 1991

A Cyclic Triaxial Facility For Loading A Silty Clay, Matthew Raybould

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

A digital control servo-hydraulic triaxial test facility with full data acquisition has been developed at Nottingham University as part of the UK Science and Engineering Research Council initiative in earthquake engineering. This apparatus is currently being used to investigate the response of a coarse silt contaminated by kaolin clay to cyclic stress and strain. High quality deformation data is generated by on sample instrumentation and enables the stiffness at very low strain levels to be determined accurately. This paper describes the development of the facility and presents some results of the tests carried out to date.

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Cyclic Load Resistance Of Vertically Reinforced Sand Subgrades, Vijay K. Puri, James A. Chae, Braja M. Das Mar 1991

Cyclic Load Resistance Of Vertically Reinforced Sand Subgrades, Vijay K. Puri, James A. Chae, Braja M. Das

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

This paper presents the results of laboratory scale model footing tests which were conducted for determining the cyclic load resistance of sand subgrades reinforced with semi-flexible vertical elements. The tests were conducted in a sandbox having a length of 91.5 cm, width 15.25 cm, and height of 61.0 cm. Steel bars 1. 58 mm in diameter were used as reinforcing elements. Tests were also conducted by using rough reinforcing elements. The test results indicate that the value of coefficient of elastic uniform compression of the footing on sand increases with the provision of vertical reinforcement in the sand subgrade. Rough …

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Cyclic Non-Linear Constitutive Equations For Sands, T. Doanh Mar 1991

Cyclic Non-Linear Constitutive Equations For Sands, T. Doanh

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

A series of triaxial cyclic tests are performed on Hostun sand; each test undergoes several two-way, strain-controlled cyclic loadings under drained conditions. The purpose of these tests is to investigate the behavior of this sand under complex loadings. This paper extends the previous works during the last years, and aims at showing that the non-linear incremental constitutive equations can describe the behavior of saturated sand subjected to various stress loadings in drained conditions.

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Degradation Behavior Of Normally Consolidated Clay Under Cyclic Loading Condition, Meei-Ling Lin, Jiang-Yuan Chen Mar 1991

Degradation Behavior Of Normally Consolidated Clay Under Cyclic Loading Condition, Meei-Ling Lin, Jiang-Yuan Chen

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

The degradation behavior of soil may become important when considering the response of soft clay under cyclic loading condition. A nonlinear model was proposed by Idriss, et al. to account for the degradation behavior based on the controlled-strain test. By adopting a numerical procedure, the data obtained in controlled-stress cyclic triaxial test can be used to find the degradation parameter defined in the nonlinear degradation model proposed by Idriss, et al. A series of consolidated-undrained controlled-stress and controlled-strain cyclic triaxial tests were performed on laboratory manufactured normally consolidated soft clay samples. The relationship between degradation parameter and strain was determined …

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Session 1: Discussions And Replies, Multiple Authors Mar 1991

Session 1: Discussions And Replies, Multiple Authors

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

No abstract provided.

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Downhole Seismic Cone Analysis Using Digital Signal Processing, R. G. Campanella, W. P. Stewart Mar 1991

Downhole Seismic Cone Analysis Using Digital Signal Processing, R. G. Campanella, W. P. Stewart

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

In-situ measurement of the dynamic characteristics of surficial soils is becoming more common in geotechnical practice for prediction of ground surface motions from earthquake excitation and to evaluate foundations for vibrating equipment. Techniques for these measurements have been under development at the University Of British Columbia (U.B.C.) since 1980. The paper discusses many practical considerations with respect to equipment (sources, receivers, trigger, etc.) and procedures that can affect the interpretation and analysis of seismic cone results. A brief review is given of the cross-over method as used at UBC to determine interval shear velocity travel times from downhole seismic cone …

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Dynamic Properties Of Saturated Coal Fly Ash, Pei-Ji Yu, Wei-Qin Qin Mar 1991

Dynamic Properties Of Saturated Coal Fly Ash, Pei-Ji Yu, Wei-Qin Qin

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

The great part of fly ash produced by thermal power plants is either sluiced or filled in disposal areas in China. The dynamic properties of fly ash are important for solving geotechnical problems relating to fly ash mass under dynamic loadings. The high temperature during combustion makes fly ash nonplastic but pozzolanic. The nonplasticity causes the dynamic properties of sluiced and just compacted fly ash to be similar to ones of silts. The pozzolanic action causes obvious aging effect for compacted fly ash, by which an aging time of 180 days may increase maximum shear modulus by 75% to 400% …

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Effects Of Hysteretic Shape On Dynamic Response, Per B. Selnes, Farrokh Nadim Mar 1991

Effects Of Hysteretic Shape On Dynamic Response, Per B. Selnes, Farrokh Nadim

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

The parameters determined in laboratory tests for use in dynamic analyses are usually the secant modulus and the area of the hysteresis loop. The accuracy of this approach was studied for highly non-linear behavior through analytical solutions and numerical simulations of a single degree of freedom system. Only the effect of the shape of the hysteresis loop was studied, i.e. the stiffness and the area of the loop were kept constant independent of amplitude. The study shows that irregular hysteresis may cause a significant increase in the response of the system in higher frequencies compared to what would be expected …

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In Situ And Laboratory Tests For The Evaluation Of Dynamic Geotechnical Properties Of A Cohesive Deposit In Florence, T. Crespellani, G. Vannucchi, A. Ghinelli Mar 1991

In Situ And Laboratory Tests For The Evaluation Of Dynamic Geotechnical Properties Of A Cohesive Deposit In Florence, T. Crespellani, G. Vannucchi, A. Ghinelli

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

In order to determine dynamic parameters to use for seismic microzoning purposes in a new development area near Florence, the dynamic behavior of the alluvial silty clays situated in the upper 60 m of the deposit was experimentally investigated using geophysical surveys and cyclic laboratory tests. Previous studies on the geotechnical properties of the clays of Florence revealed that, in spite of some similarities in a comparison with other coeval clays described in the literature this soil exhibits a few anomalies, as e.g. higher variations between field and laboratory shear waves velocities and remarkable differences in the coefficients of the …

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Seismic Downhole, Cpt, And Dmt Correlations In Sand, Thomas G. Thomann, Roman D. Hryciw Mar 1991

Seismic Downhole, Cpt, And Dmt Correlations In Sand, Thomas G. Thomann, Roman D. Hryciw

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

Results from seismic cone penetration and dilatometer tests performed in a cohesionless soil are presented and compared with previously published correlations for estimating the elastic shear modulus. Poor correlations were obtained between the elastic shear modulus, the dilatometer modulus and the cone tip resistance; however, somewhat better estimates of the elastic shear modulus were obtained using the coefficient of lateral stress and total unit weight empirically determined from the dilatometer.

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Structural Collapse Behavior Of Sands In Undrained Shear, J. D. Frost, J. L. Chameau, G. A. Leonards Mar 1991

Structural Collapse Behavior Of Sands In Undrained Shear, J. D. Frost, J. L. Chameau, G. A. Leonards

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

Results from undrained torsional shear tests are presented and used to further examine the concepts of steady state and structural collapse in sands, with emphasis on the influence of the collapse mechanism on soil behavior at steady state. It is shown that the degree to which the material collapses is dependent on the loading conditions and the initial fabric of the sand. Consequently, the steady state position in the state diagram is also function of these parameters.

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The Influence Of Large Prestrains On Dynamic Properties Of Sand, Richard Wesley Stephenson, S. K. Stringer, K. Sutterer Mar 1991

The Influence Of Large Prestrains On Dynamic Properties Of Sand, Richard Wesley Stephenson, S. K. Stringer, K. Sutterer

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

The development of the UMR Resonant Column/Torsional simple Shear device has provided the means to evaluate high and low amplitude shear moduli on a single sand specimen. Results of cyclic torsional simple shear tests showed that progressive strain increases w1th the cyclic strain amplitude and the number of cycles and decreases with density of the sand. Large accumulated prestrains were found to decrease the maximum dynamic shear modulus by 30 to 35%.

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Variation Of The Soil Geotechnical Properties At Dynamic Loading, Bohumil Svoboda Mar 1991

Variation Of The Soil Geotechnical Properties At Dynamic Loading, Bohumil Svoboda

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

Many experiments of cohesive and noncohesive soils were performed at the special dynamic laboratory Stavebni geologie Prague. The dynamic properties of these roils depend on their internal structure. The cracks of buildings may be observed in earthquake regions if they are constructed on soils that have undergone liquefaction. The special geotechnical investigation may identity these soils.

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Cyclic Strength Evaluation Of Rockfill Dams, Farhat H. Siddiqi, Richard J. Fragaszy Mar 1991

Cyclic Strength Evaluation Of Rockfill Dams, Farhat H. Siddiqi, Richard J. Fragaszy

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

A method of modeling the cyclic behavior of gravelly soils containing particles too large to be tested in standard laboratory equipment has been described. This matrix model is based on the understanding that oversize particles floating in a matrix of smaller grains can be removed without significantly affecting the cyclic behavior of the total soil. Successful modeling of the total soil requires that the matrix be tested at the same relative density as that of the total material. Cyclic triaxial test results on two different gravelly soils are presented. Results of tests performed on the total soil with maximum grain …

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