Engineering Commons^™

Dynamic Response Of Foundations On Two-Parameter Media, A. Alvapplllai, M. O. Faruque, M. Zaman

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

A finite element algorithm is presented to analyze the dynamic response of rectangular foundations resting on an elastic medium. The foundation is modeled by rectangular thin plate elements and the supporting elastic medium is represented by the two parameter model proposed by Vlasov. The natural frequencies of the foundation-elastic medium are investigated. A parametric study is conducted to examine the effects of the edge and corner forces, that are accounted for in the two parameter model, on the dynamic response of a plate subjected to a moving vertical force.

Earthquake Resistant Piles Reinforced With Ground Walls, Yoshiaki Nagataki, Hiroaki Senoo

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

A method for reducing earthquake load acting on piles by means of ground walls installed around pile foundation is proposed. First, a shaking table test was carried out. Test specimens are 1/40 scale structural models, which consist of soil, piles and a building with or without ground walls. The pile head moment of the specimens with ground walls show only 60% of that of the specimens without the ground walls. An FEM analysis was carried out for both cases and the results were compared with the test results. The comparison showed a good agreement. Furthermore, a simplified calculation method is …

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).

Experimental Studies On An Embedded Soil-Structure Interaction In A Case Of Hard Supporting Ground, Tomoyuki Lnukai, Masanori Izumi, Tamio Lmazawa, Eisuke Tanimoto

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

In order to investigate the embedment effects exerted on the vibration behavior of reactor building, a series of tests is being carried out employing the use of a large-scale test model constructed on hard ground. This paper describes the embedment effects obtained from the forced vibration tests for the following items: 1) dynamic characteristics of soil-structure interaction system; 2) dynamic ground impedance; 3) soil pressure and so on.

Experimental Studies On The Dynamic Behavior Of Soft Clay Ground-Structures Supported By Friction Pile Foundations, N. Mori, T. Kondo

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

Recently, structures are often sited on a soft ground. So, a friction pile and a floating foundation are considered a possible and promising one. The object of this paper is to study the dynamic behavior of soft clay ground-structure supported by friction pile foundation on the basis of the shaking table test. Major results are as follows; 1) the residual settlement of structure resulting from decreasing the bearing capacity of the ground, wh1ch 1s caused by the accumulation of the excess pore water pressure, is larger than that of ground without structures. 2) The initial shear stress is a main …

Lumped-Parameter Model For Foundation On Layer, John P. Wolf, Antonio Paronesso

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

A lumped-parameter model to represent a disk on the surface of a layer built-in at its base vibrating in horizontal, vertical, rocking or torsional motions is presented. Eight frequency-independent real coefficients determine the springs, dampers and the mass of the lumped-parameter model with two internal degrees of freedom. These coefficients are specified for various ratios of the radius of the disk to the depth of the layer and for various Poisson's ratios. To derive the mechanical properties of the lumped-parameter a systematic procedure of curve-fitting of the dynamic-stiffness coefficient up to at least twice the fundamental frequency of the layer …

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 …

Nonlinear Seismic Analysis Of Building - Foundation Soil Systems, M. Sobaih, A. Gabr, A. H. Mahmoud, M. M. Bahloul

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

This paper deals with the problem of nonlinear seismic analysis of building - foundation soil systems. The building considered is modeled as a shear - type building supported on the surface of homogeneous isotropic elastic half-space. The governing nonlinear equations of motion for the structure - soil system are solved in the time domain using the step-by-step linear acceleration method of analysis with Wilson-e modification. Different nonlinear models to simulate the behaviour of reinforced concrete under cyclic loading are used. A parametric study has been performed on a single story shear-type building with different natural frequencies supported on the surface …

Numerical Simulation Of Shaking Table Test By Nonlinear Response Analysis Method, Mamoru Kanatani, Koichi Nishi, Jun-Ichi Touma, Masayuki Ohnami, Hiroyuki Namita

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

In this paper we described the results or numerical simulation or shaking table test on two dimensional soil-structure interation system to verify an application or newly developed nonlinear response analysis method. This code was a so-called U-W analysis method based on the deformation theory or saturated porous material proposed by Biot and constitutive relations to simulate the nonlinear characteristics or soils were induced by the elasto-plastic theory. Input material constants or soil were decided by referring the data or popular soil element test. Because the properties or soil were heavily dependent on confining pressure, then static and dynamic soil tests …

Parametric Study Of Horizontal Permanent Displacement On Sand, H. V. Phuong Truong

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

Dynamic loading such as cyclic loading should be taken into account in designing shallow foundations for any dynamically related structures. Horizontal permanent displacement, which can occur at any time due to wind and/or wave and dynamic loads of moving vehicles, can significantly reduce the bearing capacity of the footing. Effects of dynamic soil properties, e.g. frequency, Poisson's ratio, Young's modulus, on the permanent displacement are considered and the assumption of the linear variation between deformation and cycles can be used to predict the long-term horizontal permanent displacement. Sensitivity analyses for both pure sliding and coupled rocking and sliding vibrations of …

Pile Group Stiffness For Seismic Soil-Structure Interaction, Anshuli Arya, Anand S. Arya

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

This paper deals with stiffnesses of pile groups based on single pile stiffness as worked out by Novak and Sharnouby (1983) using dynamic analysis. The interaction factors between two neighboring piles are used as those derived by Poulos (1971) statically but assumed to hold under dynamic situation at low frequencies such as involved in earthquakes. Pile groups of 4 to 32 piles in single circular ring and up to 60 piles in multiple rings as used under raft foundations of circular chimneys and overhead water tanks are accordingly analysed. It is found that the stiffness of the group is much …

Response Of Pile Under Dynamic Loading, Somnath Bandyopadhyay

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

The need for a better understanding of soil pile interaction problem under dynamic loading especially in a nonlinear soil medium has always been felt by engineers. This paper presents a PC based Finite Element I Finite Difference analysis of a Three Dimensional soil pile interaction problem in Elasto Plastic soil under transient and periodic dynamic loading. Assuming separation of variable is permitted method of Finite Element has been used over space and then the solution proceeds over time by explicit integration. Numerical experimentation with a 3 x 3 x 3 model offers a stable response which (qualitatively) with Green's function …

Seismic Behaviour Of Bridges Considering Soil-Structure Interaction, S. K. Thakkar, D. K. Mazumdar, P. R. Bose

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

The soil-structure interaction has significant effect on seismic response of bridges in many situations. The choice of soil springs for response determination is an important consideration. This paper presents a comparative assessment of the seismic response of bridge substructure by four different types of frequency independent soil springs namely, Beredugo-Novak, Wolf, Bycroft-Parmelee and Terzaghi. The variation of equivalent weighted damping and equivalent seismic coefficient is also studied. The Terzaghi's soil springs obtained by modulus of subgrade reaction approach are most flexible as compared to others. The responses are seen to be comparable with springs other than Terzaghi. The equivalent damping …

Seismic Response Analysis Of A Thick Overburden Consisting Of Loose And Soft Soil, Wenyao Hu, Zhengyuan Xia

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

It is known that not only local soil conditions but also seismic wave, used in analysis, together with its input conditions had a major effect on the intensity and characteristics of ground motion. In this paper the ground motions to different input depths of base motion under the near epicenter or far epicenter conditions, using EL CENTRO record after adjusting as base motion input, for two representative sites in Shanghai were reviewed and the results of analytical studies were presented to explore the site dependent design spectra suited to local conditions.

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.

Seismic Response Of Floating Piles To Obliquely Incident Waves, Shahid Ahmad, S. M. Mamoon

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

The response of single piles under vertically and obliquely incident SH, SV, and P waves is obtained using a hybrid boundary element (BEM) formulation. The piles are represented by compressible beam-column elements and the soil as a hysteretic viscoelastic half-space. A recently developed Green function corresponding to the dynamic Mindlin problem is implemented in the numerical formulation. Exact analytical solutions for the differential equations for the piles under distributed harmonic excitations are used. Treating the half-space as a three-dimensional elastic continuum, the interaction problem is formulated by satisfying equilibrium and displacement compatibility along the pile-soil interface. Solutions adopted for the …

Soil-Pile-Structure Interaction During Liquefaction, Shoei Nomura, Yasuhiro Shamoto, Kohji Tokimatsu

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

An analytical method is presented for evaluating dynamic response of soil-pile-structure system during soil liquefaction. The method consists of a modified Penzien's model combined with an effective stress analysis for free-field soil response and a horizontal subgrade reaction model which connects free field response with pile-structure response. Shaking table tests are conducted to study the effectiveness of the proposed procedure. A model sand deposit-pile-structure system is constructed in a large container which can permit shear deformation of the soil. Soil density, pile diameter, pile rigidity, and input motion are controlling variables in the tests. Analysis is made for both liquefied …

Soil-Structure Interaction At The Waterfront, J. M. Ferritto

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

The Navy, forced by its mission to locate at the waterfront, often on loose, saturated cohesionless soils, faces a severe liquefaction threat. Research has been in progress to evaluate the Princeton University Effective Stress Soil Model. This paper discusses that model and presents a validation example study comparing model predictions with a centrifuge experiment.

Soil-Structure Interaction Effects Based On Recorded Strong Motions During Earthquakes, Kosta Talaganov, Misko Cubrinovski

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

Presented in this paper are the results of the analyses of dynamic soil-structure interaction effects based on recorded strong motions during Montenegro (Yugoslavia) earthquake of April 15, 1979. Acceleration time histories have been recorded by strong motion instruments installed at foundation level of structures located in the epicentral area, founded in different soil conditions including stiff, medium and soft soils. Applying substructure technique from known motions at foundation level of structures, corresponding free field motions were computed. By comparison of computed free field motions and recorded motions at foundation level, dynamic soil-structure interaction effects, in different soil conditions and levels …

Soil-Structure Interaction Effects On The Response Of Meloland Bridge, E. A. Maragakis, S. Vrontinos, B. M. Douglas, S. Abdel-Ghaffar

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

A study related to the experimental data obtained from the full-scale tests of Meloland Road overcrossing is presented. The major objective of this study is to demonstrate that the soil structure interaction effects play a significant role in the dynamic response of the structure. Initially, the results from the static deformation of the bridge under the quick-release loads are presented. These results were obtained by applying a special integration technique on the experimental acceleration records. Then a preliminary analytical model of the bridge is fitted to the experimental data in order to evaluate the values of the soil-structure springs along …

Stochastic Response Of Lifeline To Spatial Variation Of Seismic Waves, Chin-Hsiung Loh

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

The spatial variation of seismic waves has an important effect on the seismic response of structures of extended length. Based on data collected from the SMART-1 array, the spatial variation of seismic waves can be examined. The purpose of this paper is to examine the effect of the spatial variation of seismic waves on a spatially distributed system. With the consideration of the soil amplification ratio between two sites and spatial variation of seismic waves, a ground deformation spectrum is developed from stochastic point of view. This spectrum can provide information useful in predicting maximum ground deformation. The seismic response …

Study On Dynamic Characteristics Of A Pile Group Foundation, Takuji Kobori, Kenji Miura, Masaaki Nakazawa, Katsuichiro Hijikata, Yuji Miyamoto, Takafumi Moroi, Yoshinao Kobayashi

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

The earthquake response of a structure on group of piles is investigated. The test model, which is employed in this study, is a foundation on four piles. Three conditions are prepared for examination of the contact effects of the foundation bottom and the backfilling effects on dynamic characteristics of the foundation on the piles. Forced vibration tests are carried out for ascertaining the impedance functions as the inertial interaction, and earthquake observations for the earthquake input motion as the kinematic interaction. On the basis of the test and the observation results, the correlation analyses are executed for examining the applicability …

The Learning From The Large Scale Lotung Soil-Structure Interaction Experiments, A. H. Hadjian, D. Anderson, W. S. Tseng, N. C. Tsai, C. Y. Chang, Y. K. Tang, H. T. Tang, J. C. Stepp

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

Blind prediction analyses and subsequent correlation studies of a 1/4-scale reinforced concrete containment model constructed at Lotung, Taiwan subject to forced vibration tests and actual earthquakes are evaluated with the objective of validating soil-structure interaction (SSI) analysis methodologies commonly used in U.S. practice. The SSI methods used range from simple soil-spring representation to more complex finite-element methods and sub structuring techniques. Both forced vibration test (FVT) data and actual earthquake induced response data have been obtained for use in validating selected SSI analysis methodologies. Considering that for forced vibration tests only the stiffness and damping characteristics of the foundation are …

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 …

A New Approach For Evaluating Stability And Deformation Of Earthstructure In Earthquake, Kuniaki Karaki, Akira Hirotani, Sadao Goto, Nobuyuki Yoshida

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

A new procedure for determining the shear strength of sand for slope stability analysis. An earthquake is proposed together with a simplified procedure for predicting deformation in earthquake. The proposed method is based on the advanced total stress method and uses undrained strength of sand with consideration on strength anisotropy. Soil parameters required in the use of proposed method as well as for deformation prediction are indicated and then results of stability and deformation analyses with the proposed method are presented for a revetment constructed on a silty sand on Tokyo Bay together with 1) field and laboratory tests results, …

Process For The Extracting Oxygen And Iron From Iron Oxide-Containing Ores, Surendra K. Kawatra, Timothy C. Eisele

Michigan Tech Patents

Oxygen and metallic iron are produced from an iron oxide-containing mineral, such as ilmenite, by extracting iron from the mineral with hydrochloric acid, separating solid residue from the resulting solution and drying same, electrolyzing the separated, iron chloride- containing solution to produce electrolytic iron and chlorine gas, combining the chlorine gas with water recovered from the drying and/or iron chloride-containing solution electrolysis steps of regenerate hydrochloric acid and recycling the hydrochloric acid to the extraction step. In an alternate embodiment, the chlorine gas is reacted with recovered water in the presence of a catalyst to produce hydrochloric acid which is …

Phase Separation In Glasses, N. J. Kreidl

Materials Science and Engineering Faculty Research & Creative Works

The detection, acceptance and further investigation of glass-glass phase separation was closely connected with the development of methods making detection possible, such as electron microscope technique pioneered and exploited by Werner Vogel, to whom this paper is dedicated on the occasion of his 65th birthday. Structures are not always found in agreement with rules derived from thermodynamic principles, and also depend on thermal history, as well as mode of preparation. The phenomenon is exemplified in many glass-forming systems. Among more recent applications are the control of crystallization by preceding phase separation as in glass-ceramics and semiconductor-doped glasses for non-linear optics. …

Preliminary Design Guide For Cold-Formed C- And Z-Members, Committee On Specifications For The Design Of Cold-Formed Steel Structural Members

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, March 1991, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A twelve page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Acuta Enews March 1991, Vol. 20, No. 3

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Telecom graduate study

Greenville Tech outgrows PBX

World-calling discounts

Call for Presentations

Update on Hawaii

Listing of exhibitors