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1991

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Articles 841 - 870 of 1363

Full-Text Articles in Engineering

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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Cellular Normal Modes: An Explanation For Alluvium Response To Earthquakes, W. R. Stephenson Mar 1991

Cellular Normal Modes: An Explanation For Alluvium Response To Earthquakes, W. R. Stephenson

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

The cellular mode concept uses simple physical reasoning to treat the response of soft sediments to earthquake shaking. It assumes that discrete areas of the ground, or "cells", have normal modes of vibration, and that each cell has its own natural frequency of vibration. Evidence indicates that shaking effects often relate directly to cell properties. Thus the 1967 Caracas, 1976 Tangshan, 1985 Mexico and 1989 San Francisco earthquakes have damage patterns, liquefaction patterns and instrumental record features which reflect the response of cellular modes. Since the introduction of the concept in 1974 a range of analytical and numerical techniques have …

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Session 8: Discussions And Replies, Multiple Authors Mar 1991

Session 8: Discussions And Replies, Multiple Authors

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

No abstract provided.

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Earthquake Ground Motion Amplification In Mexico City, Hsien-Hsiang Chiang, Nien-Yin Chang Mar 1991

Earthquake Ground Motion Amplification In Mexico City, Hsien-Hsiang Chiang, Nien-Yin Chang

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

The 1985 Michoacan earthquake caused extensive loss of life and severe damages. During the earthquake, the ground motions recorded at the soft clay sites were amplified by 8 to 50 times those at nearby rock sites. This study evaluates the factors influencing the seismic characteristics of the lakebed deposit in Mexico City. The essential components of response analysis are examined in both 1-D and 2-D soil systems. The amplification of ground motion can be evaluated in both 1-D and 2-D analyses. Results show that the soil property has much greater influence than the control motion on the surface ground motion. …

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Estimation Of Amplification Spectra For P And Sv Waves, Ken'ichi Abe, Kin'ichi Kasuda, Michiyasu Terada, Teruo Shimizu Mar 1991

Estimation Of Amplification Spectra For P And Sv Waves, Ken'ichi Abe, Kin'ichi Kasuda, Michiyasu Terada, Teruo Shimizu

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

In order to evaluate site effects on strong ground motions, the earthquake motions obtained from the vertical array deploying toward the depth of 400m and a part of the satellite array around its array are used. Dividing horizontal and vertical Lime histories into two potions which have primary and secondary arrivals respectively, their amplification spectral ratios between particular two points in and around the vertical array are examined as a problem of incident P- and SV-wave into stratified structures.

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Applications Of The Band-Limited-White Noise Source Model For Predicting Site-Specific Strong Ground Motions, Ivan G. Wong, Walter J. Silva, Robert B. Darragh, Cathy Stark, Douglas H. Wright Mar 1991

Applications Of The Band-Limited-White Noise Source Model For Predicting Site-Specific Strong Ground Motions, Ivan G. Wong, Walter J. Silva, Robert B. Darragh, Cathy Stark, Douglas H. Wright

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

Since the Band-Limited-White-Noise (BLWN) source model coupled with random vibration theory (RVT) was first developed in the early 1980's, it has been used successfully to predict strong ground motions at rock sites in different tectonic regimes. The BLWN-RVT methodology is appropriate for an engineering characterization of strong ground motions at a site since the method captures the important features of these motions in terms of peak acceleration and spectral composition and requires a minimum of input parameters. Recently, the capability to estimate strong ground motions at soil sites has been incorporated into the methodology by using RVT and plane-wave propagators …

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Geotechnical Units And The Damages Caused By Earthquakes In Valparaiso - Chile, P. Acevedo, J. Monge, M. Astroza Mar 1991

Geotechnical Units And The Damages Caused By Earthquakes In Valparaiso - Chile, P. Acevedo, J. Monge, M. Astroza

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

The geotechnical units forming the foundation soil of Valparaiso city and constituting seven zones that exhibit different stratigraphic sequences are characterized. In addition, the evolution of the artificial backfilling’s located in the seaport is reported. The damages causes by Chile Earthquake of March 3, 1985 allow to establish for each zone the MSK intensities, which are varying between 7 1/2 and 8 1/2 in the flat-ground sector of Valparaiso, and between 7 1/4 and 7 1/2 in the hills. The major intensity in the flat sector is observed in areas whose artificial backfilling’s are exhibiting greater thickness and less consistency …

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Post Evaluation On Reservoir Triggered Seismicity Of Khao Laem Dam, N. Hetrakul, B. Tanittiraporn, R. Sittipod, P. Vivattananon Mar 1991

Post Evaluation On Reservoir Triggered Seismicity Of Khao Laem Dam, N. Hetrakul, B. Tanittiraporn, R. Sittipod, P. Vivattananon

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

Investigation on reservoir associated earthquake phenomena in western part of Thailand was carried out since early 1983. After impoundment of Khao Laem Reservoir in June 1984 earthquake events had been recorded by micro seismic network around reservoir area. Evaluation of seismic parameters and earthquake pattern and the focal mechanism solutions indicate the earthquakes were triggered by impoundment and the hypocentral distribution confirm the earthquake activities along the north east direction. Results obtained from investigation clearly differentiate the reservoir induced earthquakes phenomena from natural tectonic earthquakes.

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Statistical Relations Between Intensity And Magnitude Of Southeastern United States Earthquakes, Ali A. Nowroozi Mar 1991

Statistical Relations Between Intensity And Magnitude Of Southeastern United States Earthquakes, Ali A. Nowroozi

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

The least squared, the major axis and the reduced major axis criterion are used to deduce a statistical relation between magnitude, mbLg, and intensity, I, for the earthquakes-in southeastern United States. Based on a catalog of 162 events during 1833 to 1987, with magnitudes between 1.1 and 6.9 and intensities between II and X, it is shown that the reduced major axis criterion produces: mbLg = (0.656 ± 0.058)*I + (0.402 ± 0.178), which is the best predictor equation of magnitude for the upper range of the observed intensities. The predictor equations based on the least squared …

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Impact Response Of Granular Soils, C. J. Poran, J. A. Rodriguez, K. S. Heh Mar 1991

Impact Response Of Granular Soils, C. J. Poran, J. A. Rodriguez, K. S. Heh

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

The paper describes results from an extensive experimental model study of response of dry sand to impact of a rigid pounder. In the laboratory tests a circular steel pounder was repeatedly dropped on sand contained in a large tank. Measurements included pounder acceleration and soil pressure at impact, pounder settlement, and soil densities and strains. Effects of pounder drop height, weight and contact area were investigated. A method is presented for the evaluation of global dynamic stiffness of the so1l mass affected by the impact by calculating a dynamic settlement modulus (DSM). The DSM values are determined from integration of …

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Soil Profiling By Spectral Analysis Of Surface Waves, T. Satoh, K. Yamagata, C. J. Poran, J. A. Rodriguez Mar 1991

Soil Profiling By Spectral Analysis Of Surface Waves, T. Satoh, K. Yamagata, C. J. Poran, J. A. Rodriguez

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

Methods for in-situ surface measurement and spectral analysis of Rayleigh waves for subsurface soil investigation have been tried by several researchers in recent years. The two most common methods, steady-state Rayleigh-wave and spectral-analysis-of-surface-waves (SASW) have certain disadvantages and are not used for routine soil investigation. The paper presents a system which uses a controlled vibration source with amplitude modulation and variable frequency capabilities. The electromagnetic vibrator may be varied in size and weight according to the depth of the soil strata investigated. The Rayleigh wave phase velocity dispersion curves are used to compute apparent velocity distribution in depth. An approximate …

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General Report Session 10: Wave Propagation In Soils, Chaim J. Poram Mar 1991

General Report Session 10: Wave Propagation In Soils, Chaim J. Poram

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

No abstract provided.

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A Study Of Blast Pressure From Underwater Borehole Blasting, T. S. Thandavamoorthy Mar 1991

A Study Of Blast Pressure From Underwater Borehole Blasting, T. S. Thandavamoorthy

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

The paper presents an experimental study conducted under laboratory conditions on the measurement of the pressure waves transmitted into water that are radiated from following the detonation of an explosive charge buried in a block. In order to simulate full scale blasting operations at sea, small explosive charge of 1.8g PETN was buried in a concrete block and detonated under water. Information concerning the test set-up, instrumentation, type of explosives used, scaling factor and measurement of pressure is briefly described. The paper also presents analysis of the test results in the form of FFT’s and Transfer functions and details of …

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Control Of Seismic Response Of Structures, Chris P. Pantelides Mar 1991

Control Of Seismic Response Of Structures, Chris P. Pantelides

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

Safety requirements for structures built in seismic regions have led to techniques for absorbing the energy induced to these structures by earthquakes. Passive isolation systems such as base isolators are suitable for low-rise structures but they provide only a partial solution to the problem. This paper presents three active control techniques for reducing the dynamic response of machine supporting foundations. The concept of active control is discussed and various control strategies are presented. The active tendon system (ATS), active mass damper (AMD), and active base control (ABC) mechanisms are examined. Both optimal and non-optimal control algorithms are described and numerical …

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General Report Session 11: Dynamic Characteristics Of Vibration Sources Other Than Earthquakes, Toyoaki Nogami Mar 1991

General Report Session 11: Dynamic Characteristics Of Vibration Sources Other Than Earthquakes, Toyoaki Nogami

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

No abstract provided.

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On Predictions And Performance Of Machine Foundations, George M. S. Manyando, Shamsher Prakash Mar 1991

On Predictions And Performance Of Machine Foundations, George M. S. Manyando, Shamsher Prakash

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

A model for predicting the amplitude versus frequency response for surface footings under vibrations is presented. The model considers the effects of soil nonlinearity and confining pressures on soil modulus and has been verified by comparing model predictions with performance field tests. The elastic half space analog solutions have been used to develop a computer program for this prediction model (Manyando, 1990). Soil nonlinearity has been accounted for by incorporating an iterative procedure in the computer program. The computer program was used to predict the footing response in vertical, torsional and coupled rocking and sliding vibrations. Predicted resonant amplitudes, resonant …

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Performance Of A Cement Silo Under Quarry Blast, Krishen Kumar, Gopal Ranjan, Shamsher Prakash Mar 1991

Performance Of A Cement Silo Under Quarry Blast, Krishen Kumar, Gopal Ranjan, Shamsher Prakash

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

Behaviour of a 67 m tall R.C.C. twin storage-cum-blending cement silo has been studied under blast loads from a nearby limestone quarry. This paper reports the findings of the analytical and experimental studies and verification of the results of analysis by the measurements made on the prototype structure, which agreed within 10%. Acceleration response of the structure were recorded for a blast of 2.61 t having six delays with maximum charge per delay 800 kg. A series of small and large size blasts were conducted to establish relationship between peak ground acceleration and distance from the blast. Non-dimensional acceleration response …

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Response Of Frame Foundations To Vertical Vibrations, P. J. Moore, T. P. Tan Mar 1991

Response Of Frame Foundations To Vertical Vibrations, P. J. Moore, T. P. Tan

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

A series of vertical vibration tests was carried out on small lm span steel portal frames of different stiffnesses and supported on two isolated rigid circular footings on a compacted sand deposit. Dynamic loading was applied to the center of the frame and the response was monitored by means of six accelerometers attached at various locations. The resonant frequency and the maximum amplitude of vibration were observed to be dependent on the frame stiffness and two theoretical models, the combined method and the dynamic deformation method, were used to compare calculated and observed results.

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The Optimization Principles Of The System "Mass Blast-Protected Structure", Yugeni Borisov, Boris Pishkin Mar 1991

The Optimization Principles Of The System "Mass Blast-Protected Structure", Yugeni Borisov, Boris Pishkin

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

The real work is ideological result of the investigations, which have been carried out for 25 years, on structural dynamics under the seismo-explosive loads, induced by industrial and experimental blasts, simulating natural earthquakes, and on the optimization parameters of drill explosive works in the mining quarrels.

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Behavior Of Buildings In August 21, 1988 Bihar-Nepal Earthquake, S. K. Thakkar, D. K. Paul, S. Mukerjee, S. Bandyopadhyay, Ashwani Kumar, B. V. K. Lavania Mar 1991

Behavior Of Buildings In August 21, 1988 Bihar-Nepal Earthquake, S. K. Thakkar, D. K. Paul, S. Mukerjee, S. Bandyopadhyay, Ashwani Kumar, B. V. K. Lavania

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

A moderate size earthquake rocked Bihar-Nepal border at 4.40 hrs. on August 21, 1988 causing wide spread devastation leading to loss of many lives and economic loss to the people of that region. The paper describes the study of damages occurred in masonry buildings, reinforced concrete buildings and liquefaction of the soil. The weakness of construction causes of damage and lessons learnt from the performance of structures are highlighted. The traditional and old structures without any earthquake resistance measures has suffered greater damage. The new reconstruction and strengthening measures must take into consideration the experience of failure of structures.

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Dedication To Harry B. Seed, Shamsher Prakash Mar 1991

Dedication To Harry B. Seed, Shamsher Prakash

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

No abstract provided.

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Earthquake Potential Along The Hayward Fault, California, Glenn Borchardt, J. David Rogers Mar 1991

Earthquake Potential Along The Hayward Fault, California, Glenn Borchardt, J. David Rogers

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

The Loma Prieta event probably marks a renewed period of major seismic activity in the San Francisco Bay Area. Particularly ominous is the historic record of major events a few years apart on opposite sides of the Bay in 1836 (N. Hayward fault) and 1838 (N. Peninsula, San Andreas fault) and 1865 (Loma Prieta segment, San Andreas fault), and 1868 (S. Hayward fault) (Figure 1). Recent preliminary measurements of the Holocene geologic slip rate of the Hayward fault are as much as 9 mm/yr (Lienkaemper and others 1989) - about 80% greater than the first Holocene measurements determined as recently …

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June 20, 1990 Earthquake Of Northern Iran: An Overview, F. Nateghi, S. Eshghi Mar 1991

June 20, 1990 Earthquake Of Northern Iran: An Overview, F. Nateghi, S. Eshghi

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

On the day of June 20, 1990 at 21:00 GMT (June 21, 1990, at 00:30 local time) a destructive earthquake of magnitude 7.6 shook Northern provinces of Iran. It caused widespread geotechnical and structural damages covering an approximate area of 10,000 sq. km resulting in 37,000 life losses, 100,000 injuries, and 100,000 building failures leaving more than 400,000 people homeless. This paper summarizes the post-earthquake investigations and discusses the general engineering aspects of the June 20, 1990 seismological, geotechnical, and structural aspects of the event. Lessons learned are also discussed.

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Performance Of Earth Dams During The Loma Prieta Earthquake, Leslie F. Harder Jr. Mar 1991

Performance Of Earth Dams During The Loma Prieta Earthquake, Leslie F. Harder Jr.

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

The October 17, 1989 Lorna Prieta Earthquake shook a large number of earth and rockfill darns. There were actually more than 100 darns within 50 miles of the fault rupture associated with this event. Although more than half of these embankments were less than 60 feet in height, a number of major darns were strongly shaken. In general, the darns performed satisfactory with one major darn and one minor darn developing moderate damage. A small number also developed minor to moderate cracking which required repairs. The great majority, however, sustained no significant damage. Although this result is quite encouraging, this …

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Study Of Co-Seismic Planetary Conditions For Earthquake Prediction, R. N. Ketkar, M. N. Viladkar, P. N. Agrawal Mar 1991

Study Of Co-Seismic Planetary Conditions For Earthquake Prediction, R. N. Ketkar, M. N. Viladkar, P. N. Agrawal

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

The periodicities in the occurrence of earthquakes, as indicated by the cosmic conditions, have been traced by analysing the planetary data at the time of occurrence of more than 1100 earthquakes of magnitude, M 27.0, which occurred during the period 1896 to 1965. Correlation between the transits of planets in the sensitive areas and at sensitive longitudes in the zodiac and the seismicity of California and adjoining area has been shown. Based on the analysis, a method for forecasting earthquakes is also proposed.

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Two Sequences Of Fine Grained Soil Liquefaction At Soda Lake, Pajaro River Valley, Santa Cruz County, California, J. David Rogers, C. J. Wills, M. W. Manson Mar 1991

Two Sequences Of Fine Grained Soil Liquefaction At Soda Lake, Pajaro River Valley, Santa Cruz County, California, J. David Rogers, C. J. Wills, M. W. Manson

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

Soda Lake was originally a natural lake in an abandoned meander bend of the Pajaro River. The San Andreas Fault zone lies 350 meters southwest of the lake, on a northwesterly trend. The natural lake was diked with embankments approximately 3 to 6 meters high on its 'southern and eastern sides in 1968 for use as a tailings pond. Fine waste material from Granite Rock Company's Wilson quarry, located just across the river and approximately 0.5 kilometers west of the lake, was periodically slurried by pipeline over to Soda Lake and thence hydraulically deposited from 1968 to the present. During …

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Dynamic Soil – Pile Parameters, K. Muthukrishnaiah, V. S. Raju Mar 1991

Dynamic Soil – Pile Parameters, K. Muthukrishnaiah, V. S. Raju

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

Results of lateral dynamic load tests conducted on precast driven concrete piles at two Project sites, one in South India (two individual piles) and another in Western India (one individual pile and two numbers of two-pile groups) are reported in the Paper. Shear wave velocities were determined from Cross Hole tests at the pile cut-off level at the test pile locations at the two sites. These values are compared with those reported in literature for two similar types of soils, namely, alluvial clay and alluvial sand. The subsoil conditions including Standard Penetration Test data and Static Cone Penetration Test data …

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Preliminary Report On The Geotechnical Aspects Of The Philippine Earthquake Of July 16, 1990, Kohji Tokimatsu, Shinichi Kuwayama, Saburoh Midorikawa, Akio Abe, Shuji Tamura Mar 1991

Preliminary Report On The Geotechnical Aspects Of The Philippine Earthquake Of July 16, 1990, Kohji Tokimatsu, Shinichi Kuwayama, Saburoh Midorikawa, Akio Abe, Shuji Tamura

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

The Philippine earthquake of July 16, 1990 (MS = 7.8), of which epicenter is about 100 km north of Manila city, was one of the most costly single natural disasters in Philippine history. The loss of life of over 1,600 persons resulted. Extensive damage to buildings, roads, embankments, natural slopes, and bridges was observed in a widespread area of approximately 20,000 square kilometers. One of the major causes of the damage was liquefaction of various sandy soils including artificially fills, alluvial deposits of river delta, and sandbars. This paper presents a preliminary overview of damage aspects of the earthquake, …

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Soil Amplification At Treasure Island During The Loma Prieta Earthquake, Roman D. Hryciw, Scott E. Shewbridge, Kyle M. Rollins, Michael Mchood, Matthew Homolka Mar 1991

Soil Amplification At Treasure Island During The Loma Prieta Earthquake, Roman D. Hryciw, Scott E. Shewbridge, Kyle M. Rollins, Michael Mchood, Matthew Homolka

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

The Loma Prieta Earthquake ground motions recorded on Treasure Island, a man-made fill in San Francisco Bay were considerably greater than on the adjacent Yerba Buena rock outcrop. The Yerba Buena motions were used as input to the computer program SHAKE90 for computing soil amplification at Treasure Island. Shear wave propagation velocities were obtained by seismic cone penetration testing. Reasonable agreement was observed between the computed and recorded accelerations at the strong motion recording station. The maximum computed accelerations around the island ranged from 0.13 to 0.20 g's. The degree of damage at various locations on the island correlated somewhat …

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General Report Session 5: Soil-Structure Interaction Under Dynamic Loading, E. Kausel, J. Roesset, A. H. Hadjian, J. Bielak, G. R. Martin Mar 1991

General Report Session 5: Soil-Structure Interaction Under Dynamic Loading, E. Kausel, J. Roesset, A. H. Hadjian, J. Bielak, G. R. Martin

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

No abstract provided.

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