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1991

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Articles 811 - 840 of 1363

Full-Text Articles in Engineering

Liquefaction Ground Deformation Predicted From Laboratory Tests, Mohammed H. Baziar, Ricardo Dobry Mar 1991

Liquefaction Ground Deformation Predicted From Laboratory Tests, Mohammed H. Baziar, Ricardo Dobry

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

A laboratory based approach is described to obtain the post-liquefaction steady-state shear strength of very loose, recently deposited, layered fluvial silty sand deposits susceptible to lateral spreading. Triaxial specimens are formed by the Remolded Discontinuously Vet Pluvial Soil Sample (RDVPSS preparation method. RDWPSS silty sand specimens are prepared by dumping the soil in water and a lowing for segregation and development of layers. Ten undrained tests were conducted using ranges of consolidation pressures σ̅3c = 0.2 to 2.7 kg/cm2 and Kc = σ̅1c/ σ̅3c = 1 to 2. The experiments included both monotonic compression …

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Liquefaction Potential Of Sand Layers In Foundations Of An Embankment Dam, Lrfan Saeed Mar 1991

Liquefaction Potential Of Sand Layers In Foundations Of An Embankment Dam, Lrfan Saeed

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

The liquefaction potential of sand layers present in river bed alluvium underlying a major embankment dam was evaluated under design earthquake conditions. The results of the field and laboratory investigations and dynamic analysis carried out for this purpose are described in the paper. Recommendations made to ensure the post-earthquake safety of the embankment are presented.

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Mechanical Characterization Of The Threshold Strain In Sand Liquefaction, A. Kaddouri Mar 1991

Mechanical Characterization Of The Threshold Strain In Sand Liquefaction, A. Kaddouri

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

DOBRY et al, YOUD have shown the existence of a shearing threshold strain in the vicinity of 10-4 which guides the occurrence of liquefaction. With tests on glass beads and sand from the Algiers bay, using a proper measuring system, we were able to arrive at a better resolution of this threshold and to the determination of its mechanical signification.

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Twice Dynamic Consolidation — An Unusual Application In Treating Liquefiable Saturated Sandy Loam Deposits, Yihui Qiu, Shuju Fan, Weiyuan Fan, Melyun Shi Mar 1991

Twice Dynamic Consolidation — An Unusual Application In Treating Liquefiable Saturated Sandy Loam Deposits, Yihui Qiu, Shuju Fan, Weiyuan Fan, Melyun Shi

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

More innovative methods of ground treatment have replaced traditional methods. Dynamic consolidation, for example, has been applied widespreadly in China. Presented in this paper is a case history of adopting the twice dynamic consolidation method to improve liquefiable saturated loesslike sandy loam deposit, since the site for the Aluminum Material Company which is located at the suburb of Talyuan, China, Is geotechnically adverse. In this project the effective depth of improvement increased significantly. Judged from the ln-situ investigation and laboratory triaxial shear test, the liquefaction potential was eliminated as predicted.

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Comparison Of Limit-State Seismic Earth Pressure Theories, D. G. Elms, R. Richards Jr. Mar 1991

Comparison Of Limit-State Seismic Earth Pressure Theories, D. G. Elms, R. Richards Jr.

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

The paper considers how, for the limit analysis approach to the seismic design of earth retaining structures, both the magnitude of soil force and the center of pressure vary with the type of displacement of the structure in translation or rotation. Two approaches are used. The first assumes that for a rotating wall the apparent internal friction angle of the backfill will vary for purely geometrical reasons. The second considers the effect of the peaked form of the stress-strain curve for a dense cohensionless soil. Both approaches show that, compared with a wall rotating about its base, the center of …

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Session 4: Discussions And Replies, Multiple Authors Mar 1991

Session 4: Discussions And Replies, Multiple Authors

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

No abstract provided.

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Retaining Walls; Computation Of Seismically Induced Deformations, Sreenivas Alampalli, Ahmed-W. Elgamal Mar 1991

Retaining Walls; Computation Of Seismically Induced Deformations, Sreenivas Alampalli, Ahmed-W. Elgamal

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

A two dimensional (2D) dynamic wall-soil computational model is proposed. The model accounts for wall and soil resonance, nonlinear wall-backfill soil interaction, simultaneous wall base sliding and rotation, nonlinear soil properties and possible pore pressure buildup. A bending beam with a base yielding rotational spring and a base translational slide element represents the wall. A 2D shear beam represents the soil system. The wall and supporting soil interaction through a Winkler type nonlinear no-tension spring system. An elasto-plast1c path-dependent hysteretic model accounts for nonl1near so1l behavior and possible pore pressure buildup. The seismic response of a 15m high cantilever wall …

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Seismic Design Chart For Anchored Bulkheads, George Gazetas, Panos Dakoulas Mar 1991

Seismic Design Chart For Anchored Bulkheads, George Gazetas, Panos Dakoulas

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

Evaluation of numerous case histories reveals that the seismic performance of anchored sheet pile quaywalls depends primarily on the anchoring system. Current pseudo-static procedures often lead to deficient anchoring, whose excessive displacements or failure trigger excessive permanent seaward displacement at the top of the bulkhead, accompanied by cracking and settlement behind the anchor. The results of the case histories lead to a Seismic Design Chart to be used in conjunction with the pseudo static procedure. The Chart delineates between acceptable and unacceptable degrees of damage, depending on the values of two dimensionless parameters that are functions of the material and …

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A Comparison And Study On Artificial Boundaries: Conceptual Aspects, Zifa Wang Mar 1991

A Comparison And Study On Artificial Boundaries: Conceptual Aspects, Zifa Wang

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

The paper first analyzes the characteristics of various artificial boundaries (similarity and dissimilarity) and the derivation conditions of the boundaries. The problems involved in applying the artificial boundary in numerical computation and the solution to the problem are also discussed in the paper.

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Analysis Of Bridges For Seismic Hazard Mitigation In Kentucky, Yu Ouyang, Vincent P. Drnevich, David L. Allen Mar 1991

Analysis Of Bridges For Seismic Hazard Mitigation In Kentucky, Yu Ouyang, Vincent P. Drnevich, David L. Allen

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

The priority routes have been selected for Western Kentucky which shares the most hazardous New Madrid seismic zone. As the vital links on the priority routes, bridges need to be protected from collapse during earthquakes in order to maintain the access to the route for subsequent emergency traffic. In this paper, a support-loss type of bridge collapse due to earthquake induced abutment sliding is analyzed and corresponding criteria to this type of collapse is established. The analysis methods for existing bridge abutment are advanced. A computer program based on the methods is developed and applied to evaluate the potential earthquake …

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Dynamic Behavior Of Slender Structures On Their Prestressed Foundations, Phong M. Luong Mar 1991

Dynamic Behavior Of Slender Structures On Their Prestressed Foundations, Phong M. Luong

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

A non-destructive vibratory testing, using impulsive tension slacking has been devised for the quality and safety control of overhead line towers. Several structural control experiments have been conducted on four-legged towers resting on three types of foundations: concrete stepped or pedestal blocks, steel piles and prestressed foundations. Experimental results have given significant vibratory signatures in close connection with the geotechnical response characteristics of both such slender structures and their foundations. The control of foundation mechanical behavior may be very useful in cases of earthquake resistant construction and design. This paper presents some significant results of the test program.

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Dynamic Compliance Of Pile Group Considering Nonlinear Behavior Around Piles, Koichi Kobayashi, Shintaro Yao, Nozomu Yoshida Mar 1991

Dynamic Compliance Of Pile Group Considering Nonlinear Behavior Around Piles, Koichi Kobayashi, Shintaro Yao, Nozomu Yoshida

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

Static and dynamic loading test of a foundation are carried out to obtain the behavior of a pile and a pile group. A conventional analysis based on the elastic wave theory are modified to obtain the complex rigidity of a pile group and are compared with the test results. It is shown that the analysis based on the conventional elastic wave theory are not enough to predict the dynamic behavior of piles since they do not take into account both the effect of slip and/or separation between the pile surface and the surrounding ground and the nonlinear behavior of the …

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Dynamical Analysis Of Soil-Piles Interaction Systems Under Earthquake Type Loadings, Kensuke Baba Mar 1991

Dynamical Analysis Of Soil-Piles Interaction Systems Under Earthquake Type Loadings, Kensuke Baba

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

In order to investigate and discuss a theoretical prediction on the seismic response of pile groups in soil-structure interaction systems, the dynamic characteristics of piles surrounded by soil ground due to earthquake type disturbances in addition to those excited by the loadings at the head of piles. This paper is concerned with a theoretical analysis which is based on the three-dimensional wave propagation theory to find dynamic interaction characteristics of elastic pile groups embedded in the viscoelastic soil stratum on a rigid basis, under external forces concentrated at the head of piles and uniformly distributed bedrock motion. In dealing with …

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Effect Of Soil Treatment On The Dynamic Response Of Machine Foundations, M. H. Maher, F. Venancio-Filho, S. J. Lacy Mar 1991

Effect Of Soil Treatment On The Dynamic Response Of Machine Foundations, M. H. Maher, F. Venancio-Filho, S. J. Lacy

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

Improvement of foundation soils using existing treatment techniques such as chemical, compaction and jet grouting can significantly enhance the general load bearing capacity of foundations. This paper describes the effect of soil treatment on the dynamic response of a rigid foundation subjected to steady-state, lCM-amplitude high-frequency vibrations, such as those encountered in machine foundation problems. Dynamic finite element analysis were performed to evaluate the effect of soil treatment as a function of treatment type and geometry. The treatment of foundation soil significantly reduced the amplitude of vibration of the foundation with the reduction being highly dependent on the type and …

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Experimental Studies On An Embedded Structure-Soil Interaction, Yuji Miyamoto, Yasuhiro Ohtsuka, Atsunobu Fukuoka, Toshiaki Nasuda, Masanori Izumi Mar 1991

Experimental Studies On An Embedded Structure-Soil Interaction, Yuji Miyamoto, Yasuhiro Ohtsuka, Atsunobu Fukuoka, Toshiaki Nasuda, Masanori Izumi

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

This paper describes the results of experimental studies performed the evaluation of the embedment effects on the dynamic characteristics of the structure and the correlation anlayses between the test results and the calculated results. The vibration tests of large scale models constructed on actual soil are carried out with the purpose of obtaining the basic data for verification study on analysis codes. In the correlation analyses, the methods used here are the sway-rocking model and the axisymmetric finite element method. These methods are confirmed to be applicable to analyse the response or the embedded structures.

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Nonlinear Time Domain Numerical Model For Pile Group Under Transient Dynamic Forces, Toyoaki Nogami, Kazuo Konagai, Jun Otani Mar 1991

Nonlinear Time Domain Numerical Model For Pile Group Under Transient Dynamic Forces, Toyoaki Nogami, Kazuo Konagai, Jun Otani

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

A computational model of soil-pile interaction behavior in pile and pile group was developed in this paper. Particular attention was paid to making the model simple and capable of taking into account nonlinear soil behavior, such as gapping and slippage between soil and pile, and cyclic behavior of soil. The model was developed within the frame work of the Winkler model defined in plane strain conditions. In order to analyze transient dynamic response in a rigorous manner, the model was formulated in the time domain using a step-by-step method. A transfer matrix approach was also adopted in the response computation. …

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Peculiarities Of Soil Structure Interaction In Construction With Artificial Bases, Mark A. Klyachko, Alexander M. Uzdin Mar 1991

Peculiarities Of Soil Structure Interaction In Construction With Artificial Bases, Mark A. Klyachko, Alexander M. Uzdin

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

A technique is suggested to increase seismic resistance of constructions by using alternative artificial bases. Two types of artificial bases are considered: a (consolidated) soil pad and a pile foundation (with or without pile grating). Criteria have been established for the foundation parameters required depending upon the foundation versus construction stiffness ratio. The construction of a consolidated soil pad 3 m thick (h~3m) with deformation module E0 > 30MPa on soils, which are referred, according to the All-Union Building Standard Specifications (SNIP, 1982), to soil category III, is shown to reduce the level of surface accelerations by a factor of …

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Seismic Effect Evaluation For Underground Space & Structures, John G. Z. Q. Wang, Jun Xiong Li Mar 1991

Seismic Effect Evaluation For Underground Space & Structures, John G. Z. Q. Wang, Jun Xiong Li

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

It is stressed in this paper that in a strong earthquake the damages of all the underground structures, chambers or any sort of underground space differed quite a lot from that on the ground surface. Numerous evidences show ground motion attenuates immensely downward with depth. However, the earthquake resistance design for underground structures still ignores this fact and sticks to the criteria of ground structures. As a result, very conservative and exhausting design for underground engineering were caused. Through a series of investigations and based on the comparison between the ground damages and the underground damages of the same site, …

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Seismic Fluidization And Foundation Behavior, R. Richards Jr., M. Budhu, D. G. Elms Mar 1991

Seismic Fluidization And Foundation Behavior, R. Richards Jr., M. Budhu, D. G. Elms

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

Field observations of seismic settlements of foundations on granular soils due to shear flow rather than densification or liquefaction are explained in terms of the concept of seismic fluidization. The theory is briefly reviewed and used to derive seismic bearing capacity factors for shallow foundations from the standard static formulas. The reduction of bearing capacity as accelerations increase triggers incremental settlement whenever the ground acceleration exceeds some critical level whose value depends on the static design factor of safety. The total seismic settlement can be computed for a particular earthquake record by a modified sliding block approach or related to …

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Soil Structure Interaction Analysis Of A Deeply Embedded Reactor Silo, Margaret Longstreth, Alan Appleford, Frederick F. Tajirian Mar 1991

Soil Structure Interaction Analysis Of A Deeply Embedded Reactor Silo, Margaret Longstreth, Alan Appleford, Frederick F. Tajirian

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

This paper reviews the seismic soil structure interaction (SSI) analysis performed for the Modular High Temperature Gas-cooled Reactor (MHTGR). The large depth to diameter ratio of the silo requires proper modeling of embedment and silo flexibility when evaluating the response of the structure to seismic loads. The carputer program SASSI was used to perform the three dimensional SSI analysis in order to take full advantage of embedment in reducing seismic response. Acceleration response spectra were computed for three soil sites at various points in the silo walls and internal vessels. The results demonstrated the effectiveness of embedment in reducing the …

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Assessment Of Dynamic Properties Of Wushantou Dam, J. C. Chern, M. T. Wang, T. S. Lee Mar 1991

Assessment Of Dynamic Properties Of Wushantou Dam, J. C. Chern, M. T. Wang, T. S. Lee

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

Accurate assessment of material properties is essential for a meaningful evaluation of the dynamic behavior of a dam. Comprehensive studies using in- situ measurement and laboratory testing techniques coupled with back calculations of dam responses in recorded motion gives the following conclusions : (1) Response in good agreement with actual motion can be obtained by using appropriate analytical models and material properties; (2) a laboratory test may give reasonable result, but allowance should be made for the effects of strain level, sample disturbance and reconsolidation, especially in loose, non - cohesive soil; (3) in- situ shear wave velocity measurement is …

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Assessment Of Seismic Stability Of Dolphin Pool Slope Of John Hart Dam, J. K. Lou, P. M. Byrne, S. J. Garner, W. F. Marcuson Iii Mar 1991

Assessment Of Seismic Stability Of Dolphin Pool Slope Of John Hart Dam, J. K. Lou, P. M. Byrne, S. J. Garner, W. F. Marcuson Iii

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

The John Hart Dam is in a high seismic risk area. To ensure dam safety, the Dolphin Pool Slope portion of the dam had to be rebuilt. Extensive field investigations and laboratory testing were conducted to obtain representative soil strength parameters for seismic stability analyses and rehabilitation design. Back analysis of the performance of the Dolphin Pool Slope under a 1946 earthquake loading confirmed the strength parameters determined from the field investigation and laboratory testing. Seismic analyses indicated that large zones of the dam could be expected to liquefy under the Maximum Credible Earthquake and, because of uncertainties regarding the …

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Automated Slope Stability Analysis Of Zoned Dams, P. K. Basudnar, Yudhbir Dhawan, R. K. Dhawan Mar 1991

Automated Slope Stability Analysis Of Zoned Dams, P. K. Basudnar, Yudhbir Dhawan, R. K. Dhawan

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

The study pertains to the pseudo-static stability analysis of zoned dams with geologic discontinuities in the foundation. Sequential unconstrained minimization technique in conjunction with Janbu's generalized procedure of slices has been used for finding the critical slip surface and the corresponding minimum factor of safety. The method has been found to be quite efficient in solving such problems.

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Comparison Of 2-D And 3-D Dynamic Analysis Of Effective Stress Of Earth Dams, Xhou Jian, Zeng Guoxi, Wu Shiming Mar 1991

Comparison Of 2-D And 3-D Dynamic Analysis Of Effective Stress Of Earth Dams, Xhou Jian, Zeng Guoxi, Wu Shiming

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

Presented in this paper is a comparison between the results of 2-D and 3-D dynamic effective stress analyses of a hypothetical earth dam and two real tailing dams. The study is based on a method of rigorous nonlinear dynamic analysis by taking account the interaction of the fluid and soil phase of the material.

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Session 7: Discussions And Replies, Multiple Authors Mar 1991

Session 7: Discussions And Replies, Multiple Authors

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

No abstract provided.

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Dynamic Response Analysis Of Ash-Retention Dam And Its Earthquake-Resistant Improvement, Nenghui Li, Jiamo Zhu, Zhujiang Shen Mar 1991

Dynamic Response Analysis Of Ash-Retention Dam And Its Earthquake-Resistant Improvement, Nenghui Li, Jiamo Zhu, Zhujiang Shen

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

A nonlinear stress-strain static evaluation model and an equivalent visco-elastic dynamic evaluation model, which can simulate well the static and seismic behaviors of the ash deposit, as well as the methods for analyzing the dynamic response and for improving the earthquake-resistance of the ash-retention dam are presented and illustrated through a practical engineering project in the paper.

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Modeling Of Observed Permanent Deformation At La Villita Dam, Mohamed Fadel Succarieh, Ahmed-Waeil M. Elgamal, Liping Yan Mar 1991

Modeling Of Observed Permanent Deformation At La Villita Dam, Mohamed Fadel Succarieh, Ahmed-Waeil M. Elgamal, Liping Yan

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

The observed behavior of La Villita dam in Mexico during five different earthquakes which have occurred in the period 1975-1985 is analyzed. Asymmetry observed in the recorded crest acceleration time histories is interpreted to be due to localized stick-slip behavior below the recording instrument. Yield acceleration associated with each stick-slip event can be inferred directly from these crest records. Values of observed average yield accelerations for the November 15, 1975 and September 19, 1985 earthquakes are used to predict the observed horizontal displacements during these earthquakes. Response of other soil systems involving stick-slip deformations during dynamic loading is also briefly …

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Response Of Earth Dam With Underground Concrete Cut-Off Wall, Wanhong Li, Wenshao Wang Mar 1991

Response Of Earth Dam With Underground Concrete Cut-Off Wall, Wanhong Li, Wenshao Wang

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

The response of earth dam with underground concrete cut-off wall during construction, at normal operation and under earthquake action has been evaluated and some interesting research' results such as seismic permanent displacement are obtained. A new nonlinear dynamic model of cohesionless soils, consisting of unclosed hysteresis loop, moving back bone curve and static loading curve, is presented. Shear stress ratio controlled cyclic triaxial tests and ultrasonic shear wave velocity tests have been performed to measure the parameters of the model. The shear resistance at sand/concrete interface has been studied by making tests in a torsional shear testing device.

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Selection Of Method For Seismic Slope Stability Analysis, Neven Matasovic Mar 1991

Selection Of Method For Seismic Slope Stability Analysis, Neven Matasovic

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

The seismic stability of natural slopes in clayey materials is a subject about which much uncertainty still exists. Therefore, selection of the method for the seismic slope stability analysis is an important part of solving the problem. In this paper the basic elements of the pseudo-static method, the sliding block method and the Ishihara's method are discussed. A case history of seismic stability analysis of an Adriatic coast flysch slope has been employed to evaluate the applicability and reliability of these methods. The slope is treated as an infinite slope. Although no definitive conclusions can be drawn from a single …

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Analysis Of Site Effects At The Garner Valley Downhole Array Near The San Jacinto Fault, Sandra H. Seale, Ralph J. Archuleta Mar 1991

Analysis Of Site Effects At The Garner Valley Downhole Array Near The San Jacinto Fault, Sandra H. Seale, Ralph J. Archuleta

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

The Garner Valley downhole array is located in the geologically complicated and seismologically active San Jacinto fault zone. The choice of the site and the potential for a large earthquake there are discussed. The equipment is described in detail. The data recorded through the end of 1 April 1990 are summarized. Two large events at different locations are discussed in some detail and analyzed for amplification of the signal at the surface.

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