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Articles 32341 - 32370 of 40028

Full-Text Articles in Engineering

The Dahshour (Egypt) Earthquake Of 12th Of October 1992, M. M. Soliman Apr 1995

The Dahshour (Egypt) Earthquake Of 12th Of October 1992, M. M. Soliman

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

On the 12th of October, 1992 an earthquake of 5. 7 moment magnitude hit Dahshour (Egypt) and the surrounding area. The characteristics of the building stock exposed to this earthquake is firstly presented in the paper. Then, the Dahshour earthquake is discussed in terms of the lessons that can be learned by engineers. The paper presents a short description of the geotechnical effects and the observed patterns of damage of the existing building categories and monuments. Finally, a list of the most important conclusions is introduced.

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Scaling Earthquake Motions In Geotechnical Design, M. D. Trifunac Apr 1995

Scaling Earthquake Motions In Geotechnical Design, M. D. Trifunac

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

The traditional approach to scaling earthquake ground motion for geotechnical design applications is based on peak ground acceleration. This approach is useful when the physics of the problem depends linearly only on the nature of the high frequency (short wavelength) inertial part of strong motion. For nonlinear response analyses, the representative strain (~ velocity) and the number of stress reversals (~ duration of shaking) must also be considered. For long (large) structures (bridges and dams), the relative displacement of multiple foundations and the quasi-static deformation of the complete structure may contribute to the largest design levels. Thus, the modern design …

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Uniform Probability Response Spectra For Selecting Site Specific Design Motions, M. I. Todorovska Apr 1995

Uniform Probability Response Spectra For Selecting Site Specific Design Motions, M. I. Todorovska

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

In the majority of the current building codes, the shape of a design spectrum is defined by considering only the local soil conditions. This paper examines the validity of this simplification. In particular, it is shown how effects of "deep soil" or "rock soil" conditions on uniform probability site specific spectra can be simulated by varying the geological site conditions (depth of sediments) and the distance from the fault. On the basis of the results presented in the paper and similar results from earlier papers considering the effects of the choice of the geometry of the model fault and the …

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Influence Of Ground Motion Variability On Design Spectra In Areas Of Low To Moderate Seismicity, Z. A. Lubkowski, J. W. Pappin Apr 1995

Influence Of Ground Motion Variability On Design Spectra In Areas Of Low To Moderate Seismicity, Z. A. Lubkowski, J. W. Pappin

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

This paper examines the sensitivity of uniform hazard response spectra to the variability of the ground motion attenuation in areas of low to moderate seismicity. The variabilities of a number of published attenuation relationships are examined. Many of these relationships show that the standard deviation tends to increase as the natural period increases and some show a tendency for the standard deviation to reduce as the earthquake magnitude increases. These published works tend to be derived from earthquake data for areas of high seismicity and therefore the paper includes a critical review of what values of standard deviation are appropriate …

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A New Seismic-Geotechnical Strong Motion Approach, Francois E. Heuze, Tzou-Shin Ueng, Lawrence J. Hutchings, Stephen P. Jarpe, Paul W. Kasameyer Apr 1995

A New Seismic-Geotechnical Strong Motion Approach, Francois E. Heuze, Tzou-Shin Ueng, Lawrence J. Hutchings, Stephen P. Jarpe, Paul W. Kasameyer

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

We have developed a new approach to estimate site-specific strong motion due to earthquakes on specific faults or source zones. It combines seismologic and geotechnical studies. It entails obtaining records of small earthquakes at the site, both at the surface and downhole in bedrock, as well as performing geotechnical dynamic site characterization. This new approach has the dual result of providing an optimized definition of the dynamic geotechnical site properties and providing calculated free-field, strong motion estimates. The procedure is demonstrated at the Painter Street Bridge site in Rio Dell, CA, for which we provide a range of surface motions …

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Observed Surface Breakage Due To Strike-Slip Faulting, C. A. Lazarte, J. D. Bray Apr 1995

Observed Surface Breakage Due To Strike-Slip Faulting, C. A. Lazarte, J. D. Bray

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

This paper presents observations from field studies and physical model tests to investigate the response of soil deposits to strike-slip bedrock faulting. The study is relevant to developing mitigation technique against fault-induced damage in structures located near potentially active faults. Observations of ground rupture patterns in alluvial materials following the 1992 Landers earthquake are presented. Particularly important are the observations of significant deformation away from the main trace, the width of the shear zone, and the effects of the surficial geology on the fault expression. Preliminary results from small-scale model tests simulating strike-slip rupture are also presented. The tests results …

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Review Of Geotechnical Investigations Resulting From The Roermond April 13, 1992 Earthquake, P. M. Maurenbrecher, A. Den Outer, H. J. Luger Apr 1995

Review Of Geotechnical Investigations Resulting From The Roermond April 13, 1992 Earthquake, P. M. Maurenbrecher, A. Den Outer, H. J. Luger

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

In 1987 the Engineering Geology section of the Delft University of Technology carried out a survey of the SE Netherlands to determine which areas were susceptible to liquefaction based on soil profile, groundwater levels and a Richter scale magnitude 6 earthquake along the principal rift fault through the Netherlands, the Peelrand fault system. The fault system has been active since the Triassic and forms part of the Rhine-North Sea rift system. The last major earthquake along the Peelrand fault was in 1933. Recently, in 1992, A 5.8 magnitude earthquake occurred at Roermond, near to the Dutch-German border. Though damage resulting …

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Dynamic Modeling Of Layered Systems To Moving Surface Loads: Applications, Raj Siddharthan, Gary M. Norris, Mahmoud El-Gamal Apr 1995

Dynamic Modeling Of Layered Systems To Moving Surface Loads: Applications, Raj Siddharthan, Gary M. Norris, Mahmoud El-Gamal

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

Two important application of a recently developed moving load model are described. The model uses an efficient semi analytical "finite layer" formulation of the porous medium. One application is a response of a layered sandy nonlinear porous medium, while the other is a viscoelastic pavement layer system. The study reveals that the properties of the layers and porefluid and the moving velocity of the load are important factors that affect the response of the layered system.

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Theoretical Investigations On The Nakamura's Technique, C. Lachet, P. Y. Bard Apr 1995

Theoretical Investigations On The Nakamura's Technique, C. Lachet, P. Y. Bard

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

We use synthetic calculations to investigate the spectral ratio between horizontal and vertical components (H/V ratio), derived from noise simulation, in order to appreciate the reliability of the so-called Nakamura's method for site effects applications. This ratio shows a peak whose position generally coincides with the fundamental resonance frequency. We show that this position is independent of the source function, whereas it is characteristic of the geological structure. We also compare these results with those obtained for vertical S waves and Rayleigh waves, in order to better understand the significance of this HIV peak. Finally, we show that the amplitude …

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Elastic Wave Propagation In Inhomogeneous Media Due To Surface Shock Loading, D. S. Shridhar, V. S. Chandrasekaran Apr 1995

Elastic Wave Propagation In Inhomogeneous Media Due To Surface Shock Loading, D. S. Shridhar, V. S. Chandrasekaran

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

Wave propagation due to shock loading on the surface of elastic inhomogeneous half-space is considered. The shock loading is applied over a circular area in the form of suddenly applied vertical and shear stress. The analysis makes use of semi-analytical finite element formulation and explicit time integration technique. Extrapolation algorithm is employed for modelling the transmitting boundaries. Details of numerical procedure adopted are given and results of typical analysis are presented and discussed.

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Longitudinal Waves In A Rod In An Elastic Medium, A. Bodare, I. K. Eriksson, K. Samuelsson Apr 1995

Longitudinal Waves In A Rod In An Elastic Medium, A. Bodare, I. K. Eriksson, K. Samuelsson

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

The general equations for the propagation of longitudinal waves in an infinite cylindrical rod including the effect of a surrounding elastic medium have been derived in order to obtain the relationship between the circular frequency and the wave number. A comparison has then been made with the Smith model in order to investigate the limits of the model and to refine the expressions for the spring and damming constants.

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Analysis Of Inclined Shear Waves In Vertical Bluffs, S. A. Ashford, N. Sitar Apr 1995

Analysis Of Inclined Shear Waves In Vertical Bluffs, S. A. Ashford, N. Sitar

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

The effect of inclined shear waves on the seismic response of vertical bluffs is analyzed using the generalized hyperelement. The bluffs are modeled as a stepped halfspace in the frequency domain. It is shown that the response, normalized as a function of slope height (H) divided by wavelength (λ), is amplified for waves travelling into the slope and attenuation for waves travelling away from the slope. This amplification can be as much as twice the amplification for vertically propagating waves. The results of the analysis suggest that wave orientation and inclination in relation to the slope may need to be …

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Dispersion Of Longitudinal Waves Propagating In A Continuum With Randomly Perturbated Parameters, J. Náprstek Apr 1995

Dispersion Of Longitudinal Waves Propagating In A Continuum With Randomly Perturbated Parameters, J. Náprstek

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

The author investigates the propagation of wave motion in a continuum the material parameters of which are random functions of longitudinal coordinate. The analysis is based on the theory of Markov processes and the subsequent solution on the respective Fokker-Planck-Kolmogorov equation. The fully deterministic response in the excitation point transforms into nonhomogeneous random process in the longitudinal coordinate with the growing distance. The quota of the deterministic component in overall response drops until it disappears completely. The model of uncorrelated imperfections (white noise) of the continuum is inacceptable, because it is at variance with the energy equilibrium law. The results …

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Effect Of Magnitude And Type Of Damping On Soil Amplification, Jose M. Roesset, Carlos I. Huerta, Kenneth H. Stokoe Ii Apr 1995

Effect Of Magnitude And Type Of Damping On Soil Amplification, Jose M. Roesset, Carlos I. Huerta, Kenneth H. Stokoe Ii

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

Soil Amplification studies conducted to obtain site specific seismic motions at the free surface of a soil deposit or at any other elevation (convolution process), or to determine compatible base motions at a given depth for soil structure interaction analyses (deconvolution) assume, when performed in the frequency domain simulating nonlinear soil behavior through an iterative linear analysis, that the internal soil damping is of a linear hysteretic nature. This tends to filter out excessively the high frequency components of motion for convolution studies and leads to eventual instability of the solution at a given depth (function of the soil properties) …

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Elastic Models Of Rock Due To Explosion Pressures, Sanga Tangchawal Apr 1995

Elastic Models Of Rock Due To Explosion Pressures, Sanga Tangchawal

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

Basic theories of wave pulse initiated from conventional blasting were reviewed. Mechanics of various stress wave forms of explosion pressure were proved. A new suggested solution of displacement potential by Rinehart instead of Sharpe or Duvall's suggestion, was used to find the optimum solution. From the mathematical research models, in which they were written as a package program in C language and used Microsoft visual basic as user interface, they proved that a typical cylindrical charge explosion in a bench may take on some of the characteristics of a concentrated charge explosion.

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Discussions And Replies — Session X, Multiple Authors Apr 1995

Discussions And Replies — Session X, Multiple Authors

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

No abstract provided.

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Sliding Base Isolation System For Unreinforced Buildings, M. Tehranizadeh Apr 1995

Sliding Base Isolation System For Unreinforced Buildings, M. Tehranizadeh

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

The Concept of isolating structures from the effects of ground shaking has been discussed for many years. Its practical application was delayed until the successful development has been made. One of the easiest and lowest cost of base isolation system is the sliding or pure friction type that can be used for unreinforced forced masonry bearing wall building. This type of building are very common in different parts of Iran. Preliminary studies have indicated that the represented system for small buildings situated in the seismic region works very well.

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Simple Model For Active Isolation Of Machine Foundations By Open Trenches, S. Ahmad, T. M. Ai-Hussaini Apr 1995

Simple Model For Active Isolation Of Machine Foundations By Open Trenches, S. Ahmad, T. M. Ai-Hussaini

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

Ground disturbance due to waves generated by a machine foundation can be detrimental to adjacent structures or operation of sensitive equipment nearby. For machine foundations vibrating at moderate to high frequencies, the amplitude of ground motion can be reduced significantly by installing a wave barrier around the source. A three-dimensional boundary element algorithm incorporating quadratic elements has been used to perform an extensive parametric study on the effectiveness of open trenches as wave barriers. Based on the results of the study, a simple model in the form of an algebraic expression is developed for estimating the vibration screening effectiveness of …

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Experimental And Numerical Investigation On Vibration Screening By In-Filled Trenches, S. Ahmad, J. Baker, J. Li Apr 1995

Experimental And Numerical Investigation On Vibration Screening By In-Filled Trenches, S. Ahmad, J. Baker, J. Li

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

In-filled concrete and soil-bentonite trenches have been used in practice for many years as wave barriers to reduce transmission of moderate to high frequency ground vibrations generated by machine foundations or traffic. An experimental investigation on the influence of various geometrical and material parameters on vibration screening effectiveness of in-filled barriers has been conducted. The experimental data are compared with numerical (BEM) Solutions as well as with design formulas of Ahmad and Al-Hussaini (1991).

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Screening Of Rayleigh Waves By Open Trenches, E. Conte, G. Dente Apr 1995

Screening Of Rayleigh Waves By Open Trenches, E. Conte, G. Dente

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

This paper presents results of a numerical study on the effectiveness of open trenches in reducing the ground vibration caused by propagating Rayleigh waves. The analysis is performed in the frequency domain and under conditions of plane strain using the Boundary Element Method. The soil is modelled as a homogeneous isotropic linear elastic half space. In order to represent the screening effect due to the installation of the barrier, the index ER is introduced. ER is defined as the ratio of the rate of energy transmission over the area to be protected in the presence of the trench and that …

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Dynamic Tests Of Foundations With Explosives, V. K. Lekarkin, A. G. Wilfand, D. D. Akhmedov, F. F. Zekhniev, B. B. Zukhurdinov Apr 1995

Dynamic Tests Of Foundations With Explosives, V. K. Lekarkin, A. G. Wilfand, D. D. Akhmedov, F. F. Zekhniev, B. B. Zukhurdinov

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

The dynamic tests results of bearing capacity of bases disposed of foundation on the tampered out trenches in subsiding soils fulfilled by means of explosions are represented. The main principles are stated which concern the dynamical lasting methods of the "soil-structure" system in subsiding soils by the modelled seismic load fulfilled by means of explosions; the principles concern the analysis of results of dimensions. The functional scheme and the description of work of the device for automatic controlling the seismic explosive load are represented.

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Dynamic Behavior Of Beijing Sandy Clay And The Dynamic Responses Of Beijing Subway To Traffic Vibrations, C. S. Pan, W. Cui, D. Li, F. Gao Apr 1995

Dynamic Behavior Of Beijing Sandy Clay And The Dynamic Responses Of Beijing Subway To Traffic Vibrations, C. S. Pan, W. Cui, D. Li, F. Gao

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

Experiments were carried out for the Beijing sandy clay using a triaxial apparatus Model DTC- 240 (JAPAN) with the dynamic characteristics of the soil obtained and formulated. The test data were applied to the 2-D and 3-D finite element analyses for the dynamic responses of Beijing Subway to traffic vibrations. Resulte acquired from the numerical analyses happened to be in good coincidence with the measured responses.

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Development Of New Stiffness And Damping Expressions For Footing Vibrations, H. V. P. Truong, P. J. Moore Apr 1995

Development Of New Stiffness And Damping Expressions For Footing Vibrations, H. V. P. Truong, P. J. Moore

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

New expressions for stiffness and radiation damping, which have been developed for a new forcing function, are based on the simple equation of wave propagation in a perfectly elastic half space for different modes of vibrations, particularly vertical and horizontal vibrations. A differential equation including the effect of foundation mass is presented and the results of the amplitudes of vibration obtained from this differential equation are compared with those in the standard differential equation in soil dynamics textbooks. Furthermore, added soil masses for vertical and horizontal vibrations are also derived based on the equation of wave propagation and discussed with …

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Interaction Of Adjacent Vibratory Machines, J. P. Lee, J. A. Bohinsky Apr 1995

Interaction Of Adjacent Vibratory Machines, J. P. Lee, J. A. Bohinsky

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

Due to inevitable unbalanced masses that always exist, a rotating machine will experience vibration to various extent depending on the characteristics of loads and support conditions. When two pieces of vibratory machines are installed close to each other, the vibration of either machine may further be amplified by the interaction between the two machines. In this paper, the interaction effect between two adjacent vibratory machines supported on a flexible floor was investigated. It was found that for the case investigated, the most critical condition occurred when the unbalanced forces were out-of-phase.

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The Reliability Aspects In Dynamic Engineering, G. Singh, B. M. Das Apr 1995

The Reliability Aspects In Dynamic Engineering, G. Singh, B. M. Das

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

Strides in dynamic engineering need to be accompanied by developments in risk appraisal of designs so as to respond to rapidly increasing sensitivity to and awareness of hazards. A practical, reliable and engineer-friendly methodology for design is presented in light of the critical review of the various current practices. An example is presented to illustrate the advantages of the preferred approach to improving, unifying and rationalizing design.

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Discussions And Replies — Session Xii, Multiple Authors Apr 1995

Discussions And Replies — Session Xii, Multiple Authors

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

No abstract provided.

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The Northridge Earthquake Of 1994: Ground Motions And Geotechnical Aspects, M. K. Yegian, G. V. Ghahraman, G. Gazetas, P. Dakoulas, N. Makris Apr 1995

The Northridge Earthquake Of 1994: Ground Motions And Geotechnical Aspects, M. K. Yegian, G. V. Ghahraman, G. Gazetas, P. Dakoulas, N. Makris

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

Following the January 1994 Northridge Earthquake in Southern California, the authors traveled to Los Angeles and surveyed the earthquake damage region. Subsequently, seismologic, geologic and ground motion data were compiled and evaluated. This paper presents our observations and evaluation of: geologic and soil effects; soil-structure interaction; liquefaction; slope failures and rock slides; and ground deformations.

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A New Scenario Earthquake For Southern California Based On The January 17, 1994, Northridge Earthquake, W. W. Hays Apr 1995

A New Scenario Earthquake For Southern California Based On The January 17, 1994, Northridge Earthquake, W. W. Hays

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

Prior to the M 6.8 Northridge, California, earthquake, the two principal scenarios for Southern California were based on a recurrence of a great earthquake (M 8.25) on the San Andreas Fault system and a moderate earthquake (M 6.5) on the Newport-Inglewood fault zone. Like the January 17, 1994, Northridge earthquake, the new scenario event--a blind thrust fault beneath Los Angeles--is expected to generate very high levels of ground shaking (acceleration, velocity, displacement, spectral response) in the epicentral region, trigger ground failure over a wide area; cause extensive damage to the built environment; and test all aspects of the earthquake risk …

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Solid Waste Landfill Performance During The 1994 Northridge Earthquake, A. J. Augello, J. D. Bray, R. B. Seed, N. Matasovic, E. Kavazanjian Jr. Apr 1995

Solid Waste Landfill Performance During The 1994 Northridge Earthquake, A. J. Augello, J. D. Bray, R. B. Seed, N. Matasovic, E. Kavazanjian Jr.

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

The performance of 22landfills in the Los Angeles area during the January 17, 1994 Northridge earthquake has been investigated. Observations of damage at these landfills indicate that the overall performance of solid waste landfills was encouraging. None of the surveyed landfills showed any signs of major damage. However, one geosynthetic-lined landfill experienced two tears in the geomembrane liner. Most landfills within 30 km of the zone of energy release experienced some form of cracking in the soil cover. Beyond approximately 40 km from the zone of energy release, little to no damage was observed.

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Northridge (California) Earthquake: Unique Ground Motions, Mehmet Celebi Apr 1995

Northridge (California) Earthquake: Unique Ground Motions, Mehmet Celebi

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

The Northridge (California) earthquake of 17 January 1994 generated numerous strong-motion records that are unique because they have: (a) very high peak accelerations and (b) long-duration pulses. Using digitized data available to date, the significant aspects of the strong-motions are preliminarily reviewed and their impact on earthquake engineering are discussed.

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