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Articles 180121 - 180150 of 197987

Full-Text Articles in Engineering

Anti-Seismic Reinforcement Of Pipelines In A Liquefied Ground, Takashi Akiyoshi, Kunihiko Fuchida Mar 1991

Anti-Seismic Reinforcement Of Pipelines In A Liquefied Ground, Takashi Akiyoshi, Kunihiko Fuchida

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

An anti-seismic structural-reinforcemental method for buried pipelines is presented and analytically investigated on the effectiveness for lateral flow of liquefied grounds during earthquakes. The proposed method of the reinforcement is to fix main pipelines with expansion joints to parallel auxiliary continuous pipes using iron-plates. Stiffness of liquefied soils is around pipes is represented as a coefficient of subgrade reaction between liquefied sand deposits and pipes, based on the experimental results. Analysis of the pipeline-soil spring systems is conducted using the modified transfer matrix method. Computations are performed with respect to the displacement, strain, stress, and rotational angle of joint of …

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Behaviour Of Cyclically Loaded Model Piles In Soft Clay, R. D. Purkayastha, S. Dey Mar 1991

Behaviour Of Cyclically Loaded Model Piles In Soft Clay, R. D. Purkayastha, S. Dey

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

Instability studies on offshore piles has been carried out to a very limited extent. Cyclic loading resulting from wave action is a very common phenomenon for such piles. Continuous cycling {both vertical and lateral) presumably leads to substantial degradation in pile-soil response, the ultimate result of which could be disastrous. Over the last decade and a half, some work has been done to study the pile-soil interaction behaviour under repeated cyclic loading. This paper aims to highlight and discuss the salient features and the important observations of extensive model tests on piles subjected to vertical cyclic load. The degradation of …

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Deformation Of Soil To Seismic Waves Reflected On Foundation, L. R. Stavnitser Mar 1991

Deformation Of Soil To Seismic Waves Reflected On Foundation, L. R. Stavnitser

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

Interacting with constractions foundations during earthquake elastic seismic waves form reflected waves field which interference with coming waves lead to an increase of stresses near by foundation. These stresses can exceed the earth limit of elasticity and become the reason of limited plastic deformations region formation and residual foundations seismosettlements. In order to describe this phenomenon solution of the problem of non-standard elastic wave interaction with shifting base of foundation is obtained for conditions of caused by interference reflected plastic wave generation behind the front of which medium load relief takes place which can be described using bilinear elastic-plastic model …

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Dynamic Response Of Flexible Foundations On Multilayered Medium, Wang Fuming Mar 1991

Dynamic Response Of Flexible Foundations On Multilayered Medium, Wang Fuming

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

The dynamic response of flexible strip-foundations placed on a viscoelastic multi-layered medium under conditions of plane strain and subjected to harmonic excitation is studied in this paper. A semi-analytic model is developed to determine the dynamic flexibility matrix of the medium, and the spline finite element method is employed to treat the foundation. The two methods are appropriately combined through equilibrium and compatibility considerations at the soil-foundation interface. Numerical results describing the influence of the non-homogeneity of the soil medium on the compliance are presented, and the effects of the relative stiffness Kr on the foundation response are briefly discussed.

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Evaluation Of Seismic Soil-Structure Interaction (Ssi) By Different Approaches, Dan Mircea Ghiocel, Dan Ghiocel, Traian Mauna Mar 1991

Evaluation Of Seismic Soil-Structure Interaction (Ssi) By Different Approaches, Dan Mircea Ghiocel, Dan Ghiocel, Traian Mauna

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

The paper investigates the seismic SSI effects for rigid type structures. Structural response is computed by modal synthesis versus frequency response approach. The main aspects analysed are as follows: a) the seismic SSI effects on structural response; b) shortcomings in the current SSI computational procedure; c) seismic structure –soil-structure interaction (SSSI) effects on structural response of neighbouring heavy buildings. Two case studies are presented: a shearwell multistory building (SMB) on soft clay and a massive reactor building (RB). Seismic response quantities are accelerations, displacements, stresses, floor response spectra (FRS) and spectra amplification functions (SAF).

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Nonlinear Analysis Of Circular Plates On Nonlinear Foundation, Adel A. Mahmoud, Mohamed A. Nassar, Hazem M. Gheith Mar 1991

Nonlinear Analysis Of Circular Plates On Nonlinear Foundation, Adel A. Mahmoud, Mohamed A. Nassar, Hazem M. Gheith

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

Galerkin's procedure and the modified energy expression of Banerjee are used to obtain the central deflection of circular plates with linearly varying thicknesses, resting on a linear as well as a nonlinear elastic foundation. A new series formula for the deflection has been considered. The accuracy of the method has been tested for clamped plates with movable and immovable ends under uniform static patch loading. Graphical results are drawn for the central deflection for different end conditions, different plate thicknesses and different foundation properties. Comparison of the results are made with other known results and shows a good agreement in …

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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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Seismic Response Analysis Of Pile-Supported Structure: Assessment Of Commonly Used Approximations, Toyoaki Nogami, Reed L. Mosher, H. Wayne Jones Mar 1991

Seismic Response Analysis Of Pile-Supported Structure: Assessment Of Commonly Used Approximations, Toyoaki Nogami, Reed L. Mosher, H. Wayne Jones

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

The seismic response of a pile-supported structure is formulated by the approach developed by the first author. Using this formulation, some of the crude approximations frequently used in the seismic response analysis of a soil-pile-structure system are examined. Those involved in the analysis procedure are assessed under the linear elastic condition. A commonly used nonlinear soil model for the dynamic pile response analysis is also assessed. It is found that those approximations routinely used in the analysis procedure and numerical modelling can cause significant errors in the computed response of a pile-supported structure.

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Seismic Response Of Axially Loaded Pile Group, Takaaki Kagawa Mar 1991

Seismic Response Of Axially Loaded Pile Group, Takaaki Kagawa

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

This paper presents a numerically efficient procedure for evaluating seismic responses of an axially loaded pile group. This procedure was used to clarify the impact on pile-group responses of employing different levels of soil-pile compatibility conditions. This study clearly demonstrated that the limitations and shortcomings of adapting relaxed soil-pile compatibility conditions are not negligible for pile groups with relatively small spacing ratios and with soil stiffnesses constant or decreasing with depth.

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A Model For Predicting Liquefaction Induced Displacement, Peter M. Byrne Mar 1991

A Model For Predicting Liquefaction Induced Displacement, Peter M. Byrne

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

A simple model for predicting liquefaction induced displacement is presented. The method is based on a single-degree-of-freedom system that incorporates the post-liquefaction stress-strain response of sand. The key parameters are the residual strength and the limiting shear strain, and considerable data presently exists on these two parameters from correlation with SPT (N1)60 values. Based on this data, liquefaction induced displacements from the model are compared with both field and laboratory measurements. The model predictions are found to be in excellent agreement with the measurements and indicate that liquefaction induced displacements are very sensitive to the density or …

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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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Consideration Of Earthquake Damage To Earth Dam For Irrigation In Japan, Shigeru Tani Mar 1991

Consideration Of Earthquake Damage To Earth Dam For Irrigation In Japan, Shigeru Tani

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

There are many small earth dams for irrigation called "TAMEIKE" in Japan, Most of them were constructed before modern soil engineering were established on the basis of empirical techniques. Earthquakes in the past gave much damage to these earth dams. This paper surveys damage of earthquake for those remaining on records again, and as for Nipponkai-Chubu Earthquake, detailed investigations such as in-situ test, laboratory test, analysis were made to clarify causes of the damage to earth dams. From the result of survey, the following matters were found; i.e., large damages occur at a high rate on earth dams whose foundation …

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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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One- And Two-Dimensional Analysis Of Earth Dams, D. J. Elton, C. F. Shie, T. Hadj-Hamou Mar 1991

One- And Two-Dimensional Analysis Of Earth Dams, D. J. Elton, C. F. Shie, T. Hadj-Hamou

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

Earth dams may experience reduction in shear strength due to seismically induced pore pressures. Such reduction may be large enough to result in large deformations and eventual loss of the reservoir. While the analysis of embankment dams subject to earthquake loading is a complicated process, it is required for evaluation of seismic stability. In particular, the possibility of liquefaction in older, hydraulically-filled or otherwise poorly compacted dams during earthquakes presents a threat that must be addressed. This paper compares two methods of calculating the peak dynamic shear stress (critical to liquefaction evaluation) that occurs in an embankment during an earthquake. …

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Permanent Deformation Of Earth Dam Due To Earthquake, Jia-Huan Qian, Zhen-Son Hong, Li-Zhen Zeng Mar 1991

Permanent Deformation Of Earth Dam Due To Earthquake, Jia-Huan Qian, Zhen-Son Hong, Li-Zhen Zeng

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

This paper combines the equivalent nodal force method suggested by serf et al, (1976) and equivalent inertial force method proposed by Taniguchi et al (1983, 1987). The former is fine to utilize seed's strain potential but the stress-strain curve is obtained only by static test, while the latter uses dynamic stress-strain curve, but the determination of direction of equivalent inertial force is rather difficult. The writers use the equivalent nodal force by average shear stress (τav=0.65 τmax) and assume it's direction to be coincided with static shear stress. Also dynamic stress-residual shear strain curve is obtained by …

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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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Response Of Earth Dams In Canyons Subjected To Asynchronous Base Excitation, Panos Dakoulas, Humayun Hashmi Mar 1991

Response Of Earth Dams In Canyons Subjected To Asynchronous Base Excitation, Panos Dakoulas, Humayun Hashmi

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

A mathematical solution is presented for steady-state lateral response of earth and rock fill dams in canyons subjected to asynchronous excitation consisting of obliquely incident SH waves. The dam is idealized with a 2-dimensional shear wedge and the canyon is considered rectangular and consisting of flexible rock. A parametric study is undertaken to investigate the influence of (a) the angle of incidence, (b) the impedance ratio and (c) the canyon narrowness on the steady-state response, by considering in a simplifying way the effects of the dam-canyon interaction. The results demonstrate that the above factors may have a significant effect on …

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Stability Analyses In The Ports Of Long Beach And Los Angeles, Allen M. Yourman Jr., Gerald M. Diaz Mar 1991

Stability Analyses In The Ports Of Long Beach And Los Angeles, Allen M. Yourman Jr., Gerald M. Diaz

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

The combined Ports of Los Angeles and Long Beach (Ports) have experienced extensive growth over the last three decades. A main feature of the expansions is the creation of new land by placing hydraulic fill behind rock retention dikes. This paper presents an overview of the recent history and state of practice of slope stability analyses performed for projects related to the expansion of the Ports. The geologic and seismic setting and typical soil conditions are also described. This paper is based on a review of geotechnical reports prepared for projects in both Ports and selected published papers. The various …

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The Study Of Xintan Landslide's Sterescopic Monitoring In The Changjiang River Three Gorges, Zhu Ruigeng, Lu Wenxing, Kia Yuanyou Mar 1991

The Study Of Xintan Landslide's Sterescopic Monitoring In The Changjiang River Three Gorges, Zhu Ruigeng, Lu Wenxing, Kia Yuanyou

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

This paper emphatically introduces a new landslide’s stereoscopic monitoring system that was builded in Xintan slope after failed. The movement in the underground different level can be decided through monitoring of surface by the system. The system can provide a basis to master the slope gliding regulartion so that a new prediction method may be worked out in the future.

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Attenuation Characteristics Of Ground Strains Induced During Earthquake, Ken-Ichi Tokida, Koh Aizawa, Keiichi Tamura Mar 1991

Attenuation Characteristics Of Ground Strains Induced During Earthquake, Ken-Ichi Tokida, Koh Aizawa, Keiichi Tamura

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

The appropriate estimation of ground strains Induced during earthquake is indispensable for the seismic design of buried lifeline facilities such as pipeline systems. The ground strains induced during earthquakes are calculated with use of the dense instrument array data observed during past 78 earthquakes for the surface ground at the Public Works Research Institute (PWRl) ln Tsukuba Science City in Japan. Based on the multiple regression analysis for the calculated ground strains, the empirical formulae of attenuation of maximum ground strains for such the ground condition as the PWRI campus are proposed ln terms of earthquake magnitude and epicentral distance, …

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Attenuation Laws Considering M And R Uncertainties, Sun-Rong Huo, Yuxian Hu Mar 1991

Attenuation Laws Considering M And R Uncertainties, Sun-Rong Huo, Yuxian Hu

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

Accounting for the measuring errors or uncertainties of magnitude and distance in addition to ground motion, the attenuation laws for peak horizontal ground acceleration (PGA), velocity(PGV). And displacement (PGD) are studied with a weighted consistent least-square regressional method (WCLSRM) proposed by the authors to obtain the functional relation among several random variables (R.V.). The saturation of ground motions near epicenter with respect to both magnitude and distance is also emphasized in the models. The result is that the scaling factors for distance and the linear term of magnitude in the attenuation relations regressed by the suggested method are about 16 …

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Attenuation Of Ground Vibration On Saturated Silt Clay And Rock Bases, Xian-Jian Yang Mar 1991

Attenuation Of Ground Vibration On Saturated Silt Clay And Rock Bases, Xian-Jian Yang

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

By actual measuring and theory analysis, this paper obtains the saturated water mass density and shear modulus of saturated soil , and also the major factor affecting near source attenuation by the mteration of soil skeleton and water , the later also being the major factor affecting far source attenuation. The paper inquiries into the affect of the depth of underground water on the wave propagation. For rock base, as the wave velocity of rock body wave is high and the body wave attenuation much faster than the surface wave does, so the near source attenuated generally faster than the …

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Effects Of Local Soil Conditions In The 1986 Kalamata Earthquakes, George A. Athanasopoulos Mar 1991

Effects Of Local Soil Conditions In The 1986 Kalamata Earthquakes, George A. Athanasopoulos

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

Seismic ground response analyses and simplified determinations of fundamental periods of soil profiles were conducted for nine sites of the Greek coastal city of Kalamata which was struck by two destructive small epicentral distance earthquakes in September of 1986. The response analyses were performed by using the computer program LUSH here as the fundamental periods were determined by applying simplified methods suggested in recent literature. The dynamic soil properties needed in all calculations were obtained by in-situ and laboratory testing. The results of all analyses showed differentiation of response from site to site in terms of both frequency content and …

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Evaluation Of Soil Amplification At Smart1 Array, Taiwan, Mansour Niazi Mar 1991

Evaluation Of Soil Amplification At Smart1 Array, Taiwan, Mansour Niazi

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

In a recent compilation and analysis of nearly 750 accelerograms, we studied six pairs of triaxial accelerograms recorded digitally at two neighboring sites underlain by rock and soil, respectively. The distance between the two sites, both located south of the SMART1 array in northeast Taiwan, is approximately 2 km. The epicentral distances are less than 80 km. For each component, we computed the ratios of peak and spectral amplitudes recorded at the soil site to that of the rock site, for three peak parameters and 23 spectral ordinates. The mean estimates of the soil amplification for the peak parameters range …

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Pseudo- Three-Dimensional Analysis Of Cyclic Deformation Of Ground Subject To Seismic Liquefaction, Ikuo Towhata, M. D. Shafiqui Islam Mar 1991

Pseudo- Three-Dimensional Analysis Of Cyclic Deformation Of Ground Subject To Seismic Liquefaction, Ikuo Towhata, M. D. Shafiqui Islam

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

A Numerical tool was developed to evaluate the effects of differential movement which occurs at the ground surface during earthquakes. A special emphasis is placed on liquefaction of subsoils. A complicated three-dimensional analysis was avoided by using a pseudo-three-dimensional method of finite element analysis which runs on an element mesh of the ground surface topography as seen from the sky. The present analysis takes into account the nonlinear stress-strain behavior of soils, the ground softening due to pore pressure development, and the irregularity in the topography. The proposed method was applied to several cases in which buried pipelines were damaged …

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General Report Session 9: Seismology: Predicting Strong Ground Motion For Design, Pierre-Yves Bard Mar 1991

General Report Session 9: Seismology: Predicting Strong Ground Motion For Design, Pierre-Yves Bard

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

The 14 papers of the session may be divided (somewhat artificially, of course) in three main subgroups: - a significant number (5) deal with the whole process of predicting strong ground motion for design, starting from geological / tectonic considerations and ending at a quantitative estimate of some ground motion parameters (peak acceleration, response spectrum,. .. ), either on a regional or national scale for zoning purposes (9.17, 9.24), or at a specific site for the design of some specific structures (papers 9.10, 9.13), or finally from a methodological point of view ( 9.13, 9.24, 9.26). - the 7 papers …

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Session 8: Co-Chairman's Report, John G. Anderson Mar 1991

Session 8: Co-Chairman's Report, John G. Anderson

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

No abstract provided.

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Study Of Site Response At Memphis Due To A Large New Madrid Earthquake, Shahid Ahmad, Hemand Desai, Elsa Stara-Gazetas Mar 1991

Study Of Site Response At Memphis Due To A Large New Madrid Earthquake, Shahid Ahmad, Hemand Desai, Elsa Stara-Gazetas

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

The influence of geological and geotechnical factors on potential ground motions in Memphis due to a 65km distant hypothetical M=7 New Madrid earthquake has been investigated. From the study of the seismotectonic environment and the seismicity of the region, the characteristics of the "design earthquake" are selected. A seismological model of the radiation/attenuation of the earthquake source and of the generated waves is used to generate synthetic bedrock ("hard rock") accelerograms, which are then propagated through a deep deposit of "soft-rock" to obtain input base excitations for the near-surface soil profiles. A representative soil profile for Memphis is selected from …

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Session 9: Closing Remarks, Ken-Ichi Tokida Mar 1991

Session 9: Closing Remarks, Ken-Ichi Tokida

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

No abstract provided.

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