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Articles 171691 - 171720 of 198086

Full-Text Articles in Engineering

Radiation Damping Of Soil - Foundations Interaction Systems, Yang Xianjian, Jiang Bei Mar 1998

Radiation Damping Of Soil - Foundations Interaction Systems, Yang Xianjian, Jiang Bei

International Conference on Case Histories in Geotechnical Engineering

Based on the theory of wave scatter and the velocity, the wave radiation which is caused in soil of dynamic foundation and the range of the affected depth are presented in this paper. It is pointed out that the mass ratio of foundation and the location of the foundation in the layered soil, and its propagation velocity in the affected depth, are the major factors affecting radial damping of soil-foundation system on the half space.

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Geotechnical And Geologic Features Of U.S. 189 In Provo Canyon, Utah, Thomas S. Lee, Steven H. Brandon Mar 1998

Geotechnical And Geologic Features Of U.S. 189 In Provo Canyon, Utah, Thomas S. Lee, Steven H. Brandon

International Conference on Case Histories in Geotechnical Engineering

Provo Canyon, located in north central Utah, is known to have landslide hazards for many years. Construction to widen and straighten a 2.5-mile-long section of U.S. 189 known as the “Narrows” commenced in December 1995. This project consists of twin 300-foot-long two-lane tunnels, 3/4 million cubic yards of soil and rock excavation, 60,000 square feet of cast-in-place concrete soil nailed walls, and 90,790 square feet of mechanically stabilized embankment. During excavation for some of the cuts, landslides occurred that required remediation. Cracks were noticed near the northern portal of the tunnels which necessitated immediate stabilization. Observations during construction are presented. …

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Guidelines For Sealing Geotechnical Exploratory Holes, Cameran Mirza, Robert K. Barrett Mar 1998

Guidelines For Sealing Geotechnical Exploratory Holes, Cameran Mirza, Robert K. Barrett

International Conference on Case Histories in Geotechnical Engineering

A three year research project was sponsored by the Transportation Research Board (TRB) in 1991 to determine the best materials and methods for sealing small diameter geotechnical exploratory holes. A key requirement of the research project was to verity the effectiveness of the in-place seals. Seal verification studies were conducted at two sites, one in the USA and one in Canada. Seals consisting of various bentonite products and Portland cement were installed and allowed to age. Periodic in situ hydraulic conductivity tests were performed at the Canadian site. Seal exhumation studies were conducted at the USA site. Upon completion of …

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Seismic Retrofitting Using Micropile Systems Centrifugal Model Studies, A. Benslimane, I. Juran, S. Hanna, S. Drabkin, S. Perlo, R. Frank Mar 1998

Seismic Retrofitting Using Micropile Systems Centrifugal Model Studies, A. Benslimane, I. Juran, S. Hanna, S. Drabkin, S. Perlo, R. Frank

International Conference on Case Histories in Geotechnical Engineering

A series of centrifuge tests were conducted on micropile group and network systems in order to investigate the response to earthquake loading and soil-micropile interaction behavior. Model tests on group and network systems embedded in loose to medium dry sand are described. Micropile bending moment, deflection, and acceleration were measured during testing. Dynamic p-y curves were derived from the measurements for low and high levels of shaking and were compared with the backbone p-y curves for sand recommended by API and other published data. Group and network effects were investigated for different configurations and at different levels of loading. For …

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Is It A Sinkhole?, Wayne A. Ericson, Ted J. Smith Mar 1998

Is It A Sinkhole?, Wayne A. Ericson, Ted J. Smith

International Conference on Case Histories in Geotechnical Engineering

Claims for sinkhole damages have increased significantly since the passage of legislation in 1969 requiring Florida insurance companies to provide sinkhole coverage for residential properties. At many sites, there is little surficial evidence of karst activity (i.e. Areas of subsidence and depressions) to provide a direct link between a suspected sinkhole and damage to the structure. Whatever the cause of the damage, sinkhole damage investigations are becoming increasingly important. The karstic terrain and limestone bedrock typical of west-central and central Florida make the area susceptible to sinkhole activity. However, the geologic setting and potential impacts to structures is complicated by …

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It's Not What You Pay; It's What It Costs You. A Geotechnical Engineering Case Study, J. Richard Cheeks Mar 1998

It's Not What You Pay; It's What It Costs You. A Geotechnical Engineering Case Study, J. Richard Cheeks

International Conference on Case Histories in Geotechnical Engineering

The project consists of a middle school constructed on a previously undeveloped site. Site development required leveling a mountain ridge and perimeter tills up to 150 feet deep to create the relatively level 15 acre building site. Access to the site required a 1000 foot long side hill road from the adjacent main highway. Neither the owner nor the design team obtained geotechnical investigations of the site. As a result, they failed to consider the impact of the geologic setting on seepage, ground water flow, and slope stability. Near the end of construction, slope instabilities occurred in a cut section …

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Authors' Addresses, Multiple Authors Mar 1998

Authors' Addresses, Multiple Authors

International Conference on Case Histories in Geotechnical Engineering

No abstract provided.

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Measurement And Analysis Of Civil Engineering Vibrations, Jean-Lou Chameau, Glenn J. Rix, Laurel Empie Mar 1998

Measurement And Analysis Of Civil Engineering Vibrations, Jean-Lou Chameau, Glenn J. Rix, Laurel Empie

International Conference on Case Histories in Geotechnical Engineering

Man-made vibrations caused by construction activities, blasting, rail and vehicular traffic, and machinery can have an adverse impact on buildings and facilities, human occupants of buildings, and sensitive equipment housed within these facilities. Comparisons between vibrations are often difficult because of different methods used to measure, analyze, and interpret vibration data. To facilitate these comparisons, standard methods of selecting and mounting transducers, processing vibration data, and interpreting test results are reviewed. Specific measurement and analysis techniques and maximum allowable vibration criteria used for evaluating the influence of vibrations on humans, the potential for cosmetic damage to structures, and the impact …

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Rigid And Flexible Retaining Walls During Kobe Earthquake, Susumu Lai Mar 1998

Rigid And Flexible Retaining Walls During Kobe Earthquake, Susumu Lai

International Conference on Case Histories in Geotechnical Engineering

An overview is presented on seismic performance of rigid and flexible retaining walls based on case histories during earthquakes, notably from the 1995 Kobe earthquake. Three critical issues are discussed out of these case histories: (l) If the effects of an earthquake motion are approximated in terms of a pseudo-static inertia force using the Mononobe-Okabe equation, the equivalent seismic coefficient for evaluating gross stability of retaining walls should be less than 100 %, about 60 % on average, of a peak ground acceleration specified as a fraction of gravity (amax/g); (2) Liquefaction or excess pore water pressure increase …

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Foundations Performance Of Large Diameter Tanks, J. L. M. Clemente, A. Desai, H. Senapathy, L. W. Young Jr. Mar 1998

Foundations Performance Of Large Diameter Tanks, J. L. M. Clemente, A. Desai, H. Senapathy, L. W. Young Jr.

International Conference on Case Histories in Geotechnical Engineering

The paper presents a detailed case history of foundation performance of six 60-m diameter, 15-m high, floating roof fuel oil tanks and six 96.8-m diameter, 20-m high, fixed roof process water tanks built for a large power plant. Tank walls were supported by concrete ringwall footings. General subsurface conditions at the site are discussed, along with proposed site grading and the rationale for tank foundation selection. Because vibro-replacement improvement of site soils had been used beneath settlement-sensitive structures, there was skepticism regarding the decision to support the tanks on unimproved soils. To allay doubts about the adequacy of tank foundation …

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Foundation Problems Of A Cable Stayed High Bridge And Its Approaches, Elias Sotiropoulos, Elias Alkalais Mar 1998

Foundation Problems Of A Cable Stayed High Bridge And Its Approaches, Elias Sotiropoulos, Elias Alkalais

International Conference on Case Histories in Geotechnical Engineering

The Evripos crossing project (Greece) consisted of: The main cable stayed high bridge with three spans (90m- 215m- 90m), two approach bridges with four spans (36m and 39m) and two embankments on soft marine deposits. The pylons of the main bridge were founded on cast in situ R.C. piles, 120cm diameter, embedded in ophiolithic rock or cretaceous limestones, base and skin grouted. Limestone cavities were identified by continuous recording of the borehole drilling using the Enpasol technique. A fully instrumented pile was tested for vertical and lateral loading. For the foundation of the two end piers of the high bridge …

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Non-Linear Lateral Pile Deflection Predictions In Clays, Shamsher Prakash, M. H. Chen Mar 1998

Non-Linear Lateral Pile Deflection Predictions In Clays, Shamsher Prakash, M. H. Chen

International Conference on Case Histories in Geotechnical Engineering

A method to predict lateral load-deflection relationships for single free-headed piles in clay, considering the non-linear modulus of the sub grade reaction is proposed on the basis of the analysis of full-scale test data on ten piles. The modulus of the horizontal subgrade reaction, kh, was obtained from the field load-deflection data of six piles in soft clay and four piles in stiff clay. The kh values depend on lateral (shear) strain, which is related to pile diameter and deflection. Empirical equations of normalized modulus degradation with shear strain have been proposed for both soft and stiff …

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Osterberg Load Cell Testing Of A Deep Reinforced Concrete Pile, Martin B. Hudson, Marshall Lew, Brian D. Skyers Mar 1998

Osterberg Load Cell Testing Of A Deep Reinforced Concrete Pile, Martin B. Hudson, Marshall Lew, Brian D. Skyers

International Conference on Case Histories in Geotechnical Engineering

A pedestrian bridge was constructed between two portions of a hospital in Southern California. Potentially liquefiable soils were present to a depth of about 72 feet below the ground surface. Because of the liquefiable soils, the bridge was to be supported on 30- inch-diameter cast-in-place piles drilled to a depth of approximately 90 feet below the ground surface. A test pile was constructed to confirm the soil capacities for the bridge. An Osterberg Load cell (O-cell) was placed near the middle of the test pile, and the downward load capacities of the deeper soils (below the elevation of potentially liquefiable …

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Load Tests On Drilled Shafts For Highway Bridges, Raghu N. Dass, Vijay K. Puri Mar 1998

Load Tests On Drilled Shafts For Highway Bridges, Raghu N. Dass, Vijay K. Puri

International Conference on Case Histories in Geotechnical Engineering

Most of the highway bridges arc supported on deep foundations. Safe and economical design and construction of deep foundations requires the use of rational procedures to determine the load capacity of the foundation. A static load test may be conducted to measure the response of a pile under applied load. Conventional static tests include axial compressive, axial tensile and lateral load testing. The purpose and advantages of load testing are explained in the light of large-scale construction of deep foundations for highways for the new millennia. This paper presents a case history of load tests on high capacity drilled shafts. …

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Performance Of Bored Cast-In-Situ R.C.C. Piles In Bangladesh, Md. Nurul Amin, Sabina Shanaz Mar 1998

Performance Of Bored Cast-In-Situ R.C.C. Piles In Bangladesh, Md. Nurul Amin, Sabina Shanaz

International Conference on Case Histories in Geotechnical Engineering

The major part of Bangladesh is formed of young fluvio-deltaic sedimentary deposits, laid down by the mighty rivers Ganges and Brahmaputra. There are some older deposits in the hilly regions and Pleistocene terraces. The young fluvio-dcltaic deposits are composed of unconsolidated sediments, where the upper strata are very soft. The water table remains near to the surface throughout the year. As such construction of deep foundations has become essential for tall buildings, bridges and hydraulic structures. Bored Cast-in-Situ reinforced concrete pile is widely adopted as deep foundations. It is cost effective, time saving and the equipment and technology are readily …

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Long-Term Increase In Shaft Capacity Of Driven Piles In Sand, Gary Axelsson Mar 1998

Long-Term Increase In Shaft Capacity Of Driven Piles In Sand, Gary Axelsson

International Conference on Case Histories in Geotechnical Engineering

Long-term set-up of piles in non-cohesive soil can roughly be divided into two time-dependent causes: stress relaxation leading to an increase in horizontal stress on the shaft, and soil aging leading to an increase in stiffness and dilatancy of the soil. The present paper describes a field test in which driven concrete piles, instrumented with earth pressure cells on the shaft, were tested dynamically for static pile capacity determination at different times. The objective was to measure tl1c increase in horizontal stress due to stress relaxation and compare it with the set-up evaluated from the dynamic tests. The results show …

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Shallow Foundations On A Diagenetic Limestone Formation In Qatar, W. Akili, Robert M. Jackson Mar 1998

Shallow Foundations On A Diagenetic Limestone Formation In Qatar, W. Akili, Robert M. Jackson

International Conference on Case Histories in Geotechnical Engineering

The near surface limestones in Qatar have complex lithologies and have experienced diagenetic changes after deposition. A variety of weak limestones have been encountered in combination with matrix material (rock fragments and secondary fraction). The matrix, often clayey, sometimes cemented with gypsum, anhydrite or calcite grains, is not a rock nor does it qualify as a soil. These materials are: (i) difficult to sample in the undisturbed state. (ii) extremely variable m composition and proprieties, and (iii) appear susceptible to degradation, particularly when wet. This paper presents geotechnical information from selected sites where these materials (diagenetic limestone) have been encountered. …

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Track And Support Rehabilitation 1975 On Black Mesa & Lake Powell Railroad, Gerald P. Raymond Mar 1998

Track And Support Rehabilitation 1975 On Black Mesa & Lake Powell Railroad, Gerald P. Raymond

International Conference on Case Histories in Geotechnical Engineering

Presented are the initial support and tic foundation problems of a railroad track built in 1974 to carried axle loads 21% greater than presently (1998) permitted under interchange laws. Described are the concerns related to and affecting the final rehabilitation that resulted in a final satisfactory performance. Of particular interest to the foundation engineer is the ballast, the tie and to a lesser extent the rail behaviour. The use of cobble sized river gravel in the rehabilitation permitted the establishment of guidelines for future use of this source of material where suitable quarried rock is not available. The satisfactory performance …

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Soil Improvement For Storage Tank Foundations, P. C. Sudarshan, Y. C. Chen, J. Lin, C. F. Chen Mar 1998

Soil Improvement For Storage Tank Foundations, P. C. Sudarshan, Y. C. Chen, J. Lin, C. F. Chen

International Conference on Case Histories in Geotechnical Engineering

Three 30,000m3 storage tanks are located at a hydraulic-filled reclamation site and close to an earthquake active area in Taiwan. In order to reduce the risk of liquefaction in loose silty sand of foundations, the soil improvement methods of both dynamic compaction and vibro-replacement stone column are applied. One storage tank foundation was improved using vibro-replacement stone column approach only, and the treatment pattern consisted of stone columns on a triangular grid arrangement with three spacing patterns. A combination of the dynamic compaction and vibro-replacemenr stone column technique was utilized on foundations of the others. The dynamic compaction was …

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Arresting The Moving Slopes Of Andamans − A Case Study 2.51l, Shri Pal Mar 1998

Arresting The Moving Slopes Of Andamans − A Case Study 2.51l, Shri Pal

International Conference on Case Histories in Geotechnical Engineering

Some cases of soil erosion, slope instability, mass movement of soil and damage to structures were observed in Navy and Coast Guard Area of Port Blair. Field and laboratory tests in the area were carried out which revealed that the area is unstable and prone to landslides. Main causes of instability are soil characteristics and poor subsoil drainage conditions. Some preventive measures, in the past were taken which have achieved limited success. Additional solutions based on latest technology and construction materials are suggested which shall be economical and eco-friendly.

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The Behaviour Of Two Trial Embankments At Perlis, Malaysia With Different Rates Of Construction, A. N. Hussein, A. Mcgown Mar 1998

The Behaviour Of Two Trial Embankments At Perlis, Malaysia With Different Rates Of Construction, A. N. Hussein, A. Mcgown

International Conference on Case Histories in Geotechnical Engineering

Two trial embankments namely the North and South trial embankments were constructed in the state of Perlis, Peninsular Malaysia. The embankments have a finished height of 4m and dimensions of 60m in width and 90m in length and wen; constructed side by side. The trial embankments were staged constructed with a counterberm at 2m and side slopes of 2:3. The South trial embankment was rapidly constructed in 36 days while the North embankment was slowly constructed in about one year. Detailed site investigation works included borehole logging, field and laboratory testing. These were carried out to obtain the subsoil profile …

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A Case History Of Liquefaction Flow Failures In Mountains Mine Waste Dumps, W. H. Gu, N. R. Morgenstern, R. F. Dawson, P. K. Robertson Mar 1998

A Case History Of Liquefaction Flow Failures In Mountains Mine Waste Dumps, W. H. Gu, N. R. Morgenstern, R. F. Dawson, P. K. Robertson

International Conference on Case Histories in Geotechnical Engineering

Over the past 25 years there have been a large number of flowslides in Rocky Mountain coal mine waste dumps located in British Columbia, Canada. The flowslides occurred rapidly and displayed surprisingly long distance of runout up to 2 km. Detailed field, laboratory studies, and analyses indicate that static collapse of saturated or nearly saturated sandy gravel layers within the dumps are responsible for the initial failure and ensuing flow failures. In addition to field and laboratory studies, finite element analyses were carried out on three case histories. The analysis results indicated that the flow like liquefaction failures of these …

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Effect Of Smear Due To Vertical Drains On The Behaviour Of Two Embankments Constructed On Soft Clays, B. Indraratna, I. W. Redana Mar 1998

Effect Of Smear Due To Vertical Drains On The Behaviour Of Two Embankments Constructed On Soft Clays, B. Indraratna, I. W. Redana

International Conference on Case Histories in Geotechnical Engineering

This paper describes the methodology to include the effect of smear in the prediction of settlements beneath two embankments stabilized with vertical drains. The extent of smearing around the drains was studied using a detailed analytical formulation developed by the authors and used in conjunction with the finite clement code, CRISP. The smear zone propagation around vertical drains was studied in the laboratory using a large radial drainage consolidometer. The case histories selected in this study include (a) embankment stabilized with vertical sand drains at a Naval Dockyard, Thailand, and (b) embankment stabilized with vertical band drains in soft Muar …

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Groundwater Conditions And Drainage Of A Large Slide, E. Sotiropoulos, B. Dendrou, P. Papanikolaou Mar 1998

Groundwater Conditions And Drainage Of A Large Slide, E. Sotiropoulos, B. Dendrou, P. Papanikolaou

International Conference on Case Histories in Geotechnical Engineering

A large slide of great complexity, occurred on February 18, 1995 near the village of Malakasa, 36 km North of Athens, and disrupted road and rail traffic between Athens and Thessaloniki. The material in which the slide occurred can be described as a chaotic mixture of schists and breccias which have been highly disturbed by tectonic events, by ancient landslide activity and the prevailing high groundwater pressures. An understanding of the groundwater conditions in the Malakasa landslide was essential in designing remedial measures to stabilize the slide. The presence of a permanent spring and high water levels measured near the …

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Grouting In Consideration Of Predominant Direction Of Joints In Rock Masses, Masaki Kawasaki, Hitoshi Yoshida, Yoshikazu Yamaguchi Mar 1998

Grouting In Consideration Of Predominant Direction Of Joints In Rock Masses, Masaki Kawasaki, Hitoshi Yoshida, Yoshikazu Yamaguchi

International Conference on Case Histories in Geotechnical Engineering

We conducted a grouting test in rock mass having steep joints with predominant direction, assuming blanket grouting for embankment dams. Vertical holes and inclined holes designed in consideration of the predominant direction of the joints were used as grouting holes, and the hole spacing was determined such that the number of grouting holes per unit area on a joint was the same for both cases. As a result, both tests saw a similar improvement despite the fact that the test using inclined holes had wider hole spacing than the test using vertical holes on the ground surface. We can also …

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Instrumentation, Monitoring And Analysis Of A Landslide − A Case Study, Kishor Kumar, R. K. Panigrahi Mar 1998

Instrumentation, Monitoring And Analysis Of A Landslide − A Case Study, Kishor Kumar, R. K. Panigrahi

International Conference on Case Histories in Geotechnical Engineering

Powari Landslide which is situated at Km.367 on National Highway-22, on the right bank of river Sutlej in Kinnaur District of Himachal region of North-Western Himalaya has been active since 1987 and recurring every year in the months of July-Sept and March-May. The traffic interruption due to this slide was estimated in one year as 25 full days. 60 half days and 55 less than half days. Money spent each year only to clean the slided debris was estimated approximately from 70,000 to 2,00,000 in Indian rupees. Geological and geotechnical investigations followed by instrumentation and monitoring of this typical landslide …

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An Investigation Of An Embankment Failure In Soft Clay, Bujang B. K. Huat Mar 1998

An Investigation Of An Embankment Failure In Soft Clay, Bujang B. K. Huat

International Conference on Case Histories in Geotechnical Engineering

A number of embankment founded on soft clays have become unstable during construction of a major highway project in Malaysia. One of the embankment was back analysed based on its geometry before the failure. Measured in-situ vane shear strength was used in total stress analysis to determine the factor of safety at failure. Performance of the soft clay subsoil with regards to vertical and horizontal displacements, and piezometric response, when the failure was imminent is also described.

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Landslides On Shale In Southern Illinois, Kenneth M. Berry, Thomas L. Cooling Mar 1998

Landslides On Shale In Southern Illinois, Kenneth M. Berry, Thomas L. Cooling

International Conference on Case Histories in Geotechnical Engineering

This paper presents the case histories of two landslides in southern Illinois. The first landslide presented occurred along a highway cut at Ford's Hill on Illinois Route 3 near Chester, Illinois. The second landslide occurred in the embankment of a large retention pond in southern Illinois. Both failure planes were along the surface of the weathered shale bedrock in response to excess pore pressures. Backfigured strength at the time of failure was low and at the residual strength of the weathered shale.

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Major Landslides In Sikkim − Analysis, Correction And Protective Measures: A Case Study, A. K. Gupta, D. S. Tolia Mar 1998

Major Landslides In Sikkim − Analysis, Correction And Protective Measures: A Case Study, A. K. Gupta, D. S. Tolia

International Conference on Case Histories in Geotechnical Engineering

The paper presents the case history of two major landslides in Sikkim which had proved to be a source of continual trouble for many years since 1973, causing considerable recurring financial strain on the Border Roads Organisation in order to keep the communications through Highway cuttings in the Sikkim Himalaya are exposed to hazardous landslides of a bewildering variety. Geotechnical investigations have often revealed their complex and violent nature usually associated with high and steep cuttings in immature geological settings, severe river-erosion of toe slopes particularly due to flash floods, deforestation and faulty subsurface and surface drainage conditions during heavy …

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Natural Slope Failure On Weathered Andesitic Breccia In Samigaluh Area, Indonesia, Dwikorita Karnawati Mar 1998

Natural Slope Failure On Weathered Andesitic Breccia In Samigaluh Area, Indonesia, Dwikorita Karnawati

International Conference on Case Histories in Geotechnical Engineering

Six events of landslides occurred simultaneously on weathered Andesitic Breccia in Samigaluh Area, following the heavy rainfall. Field investigation, laboratory works and slope stability analysis were carried out to assess the mechanism of the failures, their controlling factor and identify the triggering rainfall characteristics. It was found that the rainfall was the key factor inducing the failure. However, further investigation which incorporates slope hydrodynamic numerical modeling is still required, in order to find the triggering rainfall characteristics. In addition, the role of slope inclination was less significant than the soil and vegetation types covering the slopes. Finally, the landslide susceptibility …

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