Showing papers on "Foundation (engineering) published in 2000"
Book•
20 Jul 2000
TL;DR: In this paper, the authors present a broad overview of foundation design and its application in the field of soil engineering, including the following: 1. Deep Foundations-Axial Load Capacity Based on Static Load Tests. 2. Groundwater Classification.
Abstract: (NOTE: Most chapters include Questions and Practice Problems, Summary, and Comprehensive Questions and Practice Problems.) I. GENERAL PRINCIPLES. 1. Foundations in Civil Engineering. The Emergence of Modern Foundation Engineering. The Foundation Engineer. Uncertainties. Building Codes. Classification of Foundations. 2. Performance Requirements. Design Loads. Strength Requirements. Serviceability Requirements. Constructibility Requirements. Economic Requirements. 3. Soil Mechanics. Soil Composition. Soil Classification. Groundwater. Stress. Compressibility and Settlement. Strength. 4. Site Exploration and Characterization. Site Exploration. Laboratory Testing. In-Situ Testing. Synthesis of Field and Laboratory Data. Economics. II. SHALLOW FOUNDATION ANALYSIS AND DESIGN. 5. Shallow Foundations. Spread Footings. Mats. Bearing Pressure. 6. Shallow Foundations-Bearing Capacity. Bearing Capacity Failures. Bearing Capacity Analyses in Soil-General Shear Case. Groundwater Effects. Allowable Bearing Capacity. Selection of Soil Strength Parameters. Bearing Capacity Analyses-Local and Punching Shear Cases. Bearing Capacity on Layered Soils. Accuracy of Bearing Capacity Analyses. Bearing Spreadsheet. 7. Shallow Foundations-Settlement. Design Requirements. Overview of Settlement Analysis Methods. Induced Stresses beneath Shallow Foundations. Settlement Analyses Based on Laboratory Tests. Settlement Spreadsheet. Settlement Analyses Based on In-Situ Tests. Schmertmann Spreadsheet. Settlement of Foundations of Stratified Soils. Differential Settlement. Rate of Settlement. Accuracy of Settlement Predictions. 8. Spread Footings-Geotechnical Design. Design for Concentric Downward Loads. Design for Eccentric or Moment Loads. Design for Shear Loads. Design for Wind or Seismic Loads. Lightly-Loaded Footings. Footings on or near Slopes. Footings on Frozen Soils. Footings on Soils Prone to Scour. Footings on Rock. 9. Spread Footings-Structural Design. Selection of Materials. Basis for Design Methods. Design Loads. Minimum Cover Requirements and Standard Dimensions. Square Footings. Continuous Footings. Rectangular Footings. Combined Footings. Lightly-Loaded Footings. Connections with the Superstructure. 10. Mats. Rigid Methods. Nonrigid Methods. Determining the Coefficient of Subgrade Reaction. Structural Design. Settlement. Bearing Capacity. III. DEEP FOUNDATION ANALYSIS AND DESIGN. 11. Deep Foundations. Types of Deep Foundations and Definitions. Load Transfer. Piles. Drilled Shafts. Caissons. Mandrel-Driven Thin-Shells Filled with Concrete. Auger-Cast Piles. Pressure-Injected Footings. Pile-Supported and Pile-Enhanced Mats. Anchors. 12. Deep Foundations-Structural Integrity. Design Philosophy. Loads and Stresses. Piles. Drilled Shafts. Caps. Grade Beams. 13. Deep Foundations-Axial Load Capacity Based on Static Load Tests. Load Transfer. Conventional Load Tests. Interpretation of Test Results. Mobilization of Soil Resistance. Instrumented Load Tests. Osterberg Load Tests. When and Where to Use Full-Scale Load Tests. 14. Deep Foundations-Axial Load Capacity Based on Analytical Methods. Changes in Soil during Construction. Toe Bearing. Side Friction. Upward Load Capacity. Analyses Based on CPT Results. Group Effects. Settlement. 15. Deep Foundations-Axial Load Capacity Based on Dynamic Methods. Pile-Driving Formulas. Wave Equation Analyses. High-Strain Dynamic Testing. Low-Strain Dynamic Testing. Conclusions. 16. Deep Foundations-Lateral Load Capacity. Batter Piles. Response to Lateral Loads. Methods of Evaluating Lateral Load Capacity. p-y Method. Evans and Duncan's Method. Group Effects. Improving Lateral Capacity. 17. Deep Foundations-Design. Design Service Loads and Allowable Definitions. Subsurface Characterization. Foundation Type. Lateral Load Capacity. Axial Load Capacity. Driveability. Structural Design. Special Design Considerations. Verification and Redesign during Construction. Integrity Testing. IV. SPECIAL TOPICS. 18. Foundations on Weak and Compressible Soils. Deep Foundations. Shallow Foundations. Floating Foundations. Soil Improvement. 19. Foundations on Expansive Soils. The Nature, Origin, and Occurrence of Expansive Soils. Identifying, Testing, and Evaluating Expansive Soils. Estimating Potential Heave. Typical Structural Distress Patterns. Preventive Design and Construction Measures. Other Sources of Heave. 20. Foundations on Collapsible Soils. Origin and Occurrence of Collapsible Soils. Identification, Sampling, and Testing. Wetting Processes. Settlement Computations. Collapse in Deep Compacted Fills. Preventive and Remedial Measures. 21. Reliability-Based Design. Methods. LRFD for Structural Strength Requirements. LRFD for Geotechnical Strength Requirements. Serviceability Requirements. The Role of Engineering Judgement. Transition of LRFD. V. EARTH RETAINING STRUCTURE ANALYSIS AND DESIGN. 22. Earth-Retaining Structures. Externally Stabilized Systems. Internally Stabilized Systems. 23. Lateral Earth Pressures. Horizontal Stresses in Soil. Classical Lateral Earth Pressure Theories. Lateral Earth Pressures in Soils with c ...o and ... ...o 0. Equivalent Fluid Method. Presumptive Lateral Earth Pressures. Lateral Earth Pressures from Surcharge Loads. Groundwater Effects. Practical Application. 24. Cantilever Retaining Walls. External Stability. Retwall Spreadsheet. Internal Stability (Structural Design). Drainage and Waterproofing. Avoidance of Frost Heave Problems. 25. Sheet Pile Walls. Materials. Construction Methods and Equipment. Cantilever Sheet Pile Walls. Braced or Anchored Sheet Pile Walls. Appendix A: Unit Conversion Factors. Appendix B: Computer Software. References. Index.
409 citations
1 Jan 2000
TL;DR: The foundation of natural right as discussed by the authors, a.k.a., the right to natural right, is a fundamental principle of the right of a person to be free from discrimination.
Abstract: foundation of natural right , foundation of natural right , کتابخانه مرکزی دانشگاه علوم پزشکی تهران
316 citations
1 Jan 2000
TL;DR: In this article, the authors describe the work of the National Science Foundation (NSF), Office of Naval Research (ONR), Minnesota Supercomputer Institute (MSI), and University of Minnesota.
Abstract: National Science Foundation
Office of Naval research
Minnesota Supercomputer Institute, University of Minnesota
170 citations
TL;DR: In this paper, the authors describe some of the challenges met by the designers of the foundation systems for offshore wind energy developments, and highlight the possibilities of a novel form of foundation: the suction caisson.
Abstract: We describe briefly some of the challenges met by the designers of the foundation systems for offshore wind energy developments. Although some experience from the offshore oil and gas industry proves valuable, the size and nature of typical wind turbines means that the loadings on the foundations are quite different from those encountered previously offshore. The most economical solutions are also likely to differ from those conventionally used offshore. We highlight the possibilities of a novel form of foundation: the suction caisson.
168 citations
Journal Article•
118 citations
TL;DR: In this paper, a pile foundation, composed of cast-in-place reinforced concrete piles and subjected to one-side cyclic lateral loading up to the ultimate state, is simulated with the three-dimensional elasto-plastic finite element analysis (DGPILE-3D).
87 citations
85 citations
1 Dec 2000
TL;DR: In this article, a geosynthetic-reinforced soil system was designed and constructed to support both the foundation of a two-span bridge and the approaching roadway structure, and three sections were instrumented to provide information on external movements, internal soil stresses, geogrid strains, and moisture content during various construction stages and after the structure opening to traffic.
Abstract: This paper describes a unique field application in which a geosynthetic-reinforced soil system was designed and constructed to support both the foundation of a two-span bridge and the approaching roadway structure. The reinforced soil system not only provides bridge support, but it was also designed to alleviate the common bridge bump problem. This structure was considered experimental and comprehensive material testing and instrumentation programs were conducted. These programs would allow assessment of the overall structure performance and evaluation of Colorado Department of Transportation and AASHTO design assumptions and procedures for reinforced soil structures supporting both bridge foundations and approaching roadway structures. Large-size direct shear and triaxial tests were conducted to determine representative shear strength properties and constitutive relations of the gravelly backfill used for construction. Three sections were instrumented to provide information on external movements, internal soil stresses, geogrid strains, and moisture content during various construction stages and after the structure opening to traffic. Results from a pilot (Phase I) instrumentation program and some preliminary results from a more comprehensive (Phase II) instrumentation program are presented in the paper. The results suggest that current design procedures lead to a conservative estimation of both the backfill material strength and horizontal earth pressures, and that the overall performance of this structure, before its opening to traffic, has been satisfactory.
85 citations
TL;DR: In this paper, the results of laboratory reduced-scale model tests conducted to determine the ultimate bearing capacity of a strip foundation supported by medium and dense sand reinforced by multiple layers of geogrid are presented.
Abstract: Results of laboratory reduced-scale model tests conducted to determine the ultimate bearing capacity of a strip foundation supported by medium and dense sand reinforced by multiple layers of geogrid are presented. Only one type of sand and one type of geogrid were used. Tests were conducted for surface foundation conditions and for foundations at various depths; the foundation depths were limited to less than the width of the foundation. Based on the test results, for a given thickness of the reinforcement zone, the bearing capacity ratio increases when the depth of the foundation is greater than zero (i.e. the surface foundation condition).
Book•
13 Oct 2000
TL;DR: In this article, the nature of soils water behaviour in soils site preparation and land planning is discussed, as well as soil mechanics and foundation design parameters: soil mechanics - evaluation of soil properties, clay mineralogy, soil classification, soil and water relations, capillary and pore pressure, kinetic water, strength concepts foundations-bearing capacity of shallow foundations, stress distribution and settlement, bearing capacity of piers and piles.
Abstract: Part 1 Soil problems in civil engineering: the nature of soils water behaviour in soils site preparation and land planning. Part 2 Soil mechanics and foundation design parameters: soil mechanics - evaluation of soil properties, clay mineralogy, soil classification, soil and water relations, capillary and pore pressure, kinetic water, strength concepts foundations - bearing capacity of shallow foundations, stress distribution and settlement, bearing capacity of piers and piles. Part 3 Foundation construction and engineering: concrete - constituent materials, computation of average compression strength and mix proportioning, quality assurance, mechanical properties, cold and hot weather concreting, pumping of concrete fundamentals of reinforced concrete foundation design procedures in concrete construction - piers and pile foundations earth pressure and retaining systems.
Patent•
6 Mar 2000
TL;DR: In this paper, an above ground tower foundation using embedded tension/compression components secured to a ground level cap is described, where the components each terminate distally in a below ground soil or rock anchor.
Abstract: An above ground tower foundation uses embedded tension/compression components secured to a ground level cap. The components each terminate distally in a below ground soil or rock anchoring structure. The components embed without deep wide area site excavation or dewatering. The components with their distal anchoring structure provide exceptional bearing and tension capacity to the foundation, and high resistance to overturning moments acting on the tower. The tension/compression components may be straight or tapered piles with distal end helical fins, piles with a distal end grouted soil or rock anchor, caissons with a distal belled section, caissons with a distal end grouted soil or rock anchor, helical screw anchors or any combinations thereof Construction of this foundation comprises the following steps. A minimal ground-level excavation is established for the cap. The tension/compression components embed into deep, high-strength soil layers without deep below ground excavation. The cap is formed. The components are secured to the cap. The tower attaches to the cap. Preferred tension/compression components are spin-fin piles—a pile with a helical fin at the distal pile end. The tension/compression components may be battered outwardly from the cap and tower.
1 Jan 2000
TL;DR: In this paper, different strategies have been proposed to deal with nonlinearity and irreversibility of soil behavior, affecting the response of any geotechnical structure, be it a foundation, an excavation, an earth dam, or a natural slope.
Abstract: Non-linearity and irreversibility are striking features of soil behavior, affecting the response of any geotechnical “structure”, be it, for example, a foundation, an excavation, an earth dam, or a natural slope. From a mathematical viewpoint (i.e., at the constitutive level), different strategies have been proposed to deal with such features of soil behavior, including:
TL;DR: The present essay lays out the major components of Wiener's computer ethics foundation in order to initiate among philosophers a long-overdue discussion and examination of Wieners' computer ethics accomplishments.
Abstract: N orbert Wiener's monumental computer ethics book The Human Use of Human Beings, first published in 1950, ~ makes important use of ideas that can be traced as far back into history as Aristotle. Combining Aristotelian ideas about animal physiology, behavior and the purpose of a human life with the new science of \"cybernetics\" (the science of \"information feedback\" which Wiener and others had recently created), Wiener laid down in 1950 a comprehensive foundation that remains today half a century later a powerful basis for practicing computer ethics. Wiener's ethical approach, however, is significantly different from Aristotle's, since he adopts as ethically central three \"great principles of justice\", rather than using virtues and vices like Aristotle. The present essay lays out the major components of Wiener's computer ethics foundation in order to initiate among philosophers a long-overdue discussion and examination of Wiener's computer ethics accomplishments. Presented here is an exegesis of Wiener's main ideas, rather than a philosophical defense or critique of them. Such a project would be a very ambitious undertaking that would require a book instead of an article. (Philosophers will nevertheless find, in the present essa$ a variety of ideas to debate and explore. 2)
TL;DR: In this article, the authors studied the effect of rotor-bearing foundation effects on the dynamic characteristics of rotor bearing systems based on the finite element method and proposed a substructure procedure which includes the foundation effects in the motion equations and the application of the dynamic solver of a commercial package.
19 Nov 2000
TL;DR: In this paper, the authors address the background to the provisions in the Eurocode, will cover shallow foundations and deep foundations, and review differences between low level response for which the soil can be expected to remain elastic and other situations where nonlinear behaviour of the soil adjacent to the foundation occurs.
Abstract: The first generic class of aseismic foundation design problem relates to the design of new foundations. Once earthquake risk and site effects have been evaluated the designer needs to proceed with the proportioning of the foundation. To date there is little in the way of code based recommendations to cover this. Eurocode 8 (the structural design code in the new Eurocode series) is an exception and contains an extensive section on the design of foundations to resist earthquake loading. This has been developed using the results of a number of special investigations, both laboratory and theoretical. This paper will address the background to the provisions in the Eurocode, will cover shallow foundations and deep foundations, and review differences between low level response for which the soil can be expected to remain elastic and other situations where nonlinear behaviour of the soil adjacent to the foundation occurs.
TL;DR: In this paper, a dynamic response FE analysis that incorporates a cyclic elasto-plastic constitutive model for sand, a cycle-based model for clay, and Biot's two phase mixture theory was applied to verify the ability of a numerical method to predict earthquake-induced deformation of soil embankments.
TL;DR: In this paper, the authors presented an algorithm of calculations of a thick plate on the Kolar-Nemec's subsoil by the finite/infinite element method.
1 Jun 2000
TL;DR: The Founders/Meadows Bridge as mentioned in this paper is a two-span bridge supported by a system of geosynthetic-reinforced segmental retaining walls, which was designed to alleviate the common bridge approach bump problem.
Abstract: In July of 1999, the Colorado Department of Transportation (CDOT) successfully completed the construction of the new Founders/Meadows Bridge near Denver. In this project, both the two-span bridge and the approaching roadway structures are supported by a system of geosynthetic-reinforced segmental retaining walls. The reinforced soil system not only provides bridge support, but it was also designed to alleviate the common bridge approach bump problem. Placement of shallow foundations supporting the high bridge superstructure loads on the top of mechanically stabilized earth (MSE) walls leads to reinforcement tensions and soil stresses mobilized in a different manner than in the case of MSE walls supporting small surcharge loads. This structure was considered experimental and comprehensive material testing and instrumentation programs were conducted. These programs would allow assessment of the overall structure performance and evaluation of CDOT and AASHTO design assumptions and procedures for reinforced soil structures supporting both bridge foundations and approaching roadway structures. Three sections were instrumented to provide information on external movements, internal soil stresses, temperatures, moisture content, and geogrid strains during various construction stages and after the structure opening to traffic. This report initially presents an overview of the reinforced soil wall system design, materials, construction stages, and the instrumentation program. Results of large-size triaxial and direct shear tests on the gravelly backfill soil material and preliminary instrumentation results are presented and discussed. The instrumentation results suggest that the overall performance of this structure, before its opening to traffic, has been satisfactory. CDOT design guidelines of assuming zero cohesion for the backfill strength and testing specimens without the gravel portion of the soil lead to significant underestimation of the actual shear strength of the backfill. The design and construction of geosynthetic-reinforced walls supporting bridge and approaching roadway structures should be considered in the future for field conditions similar to those encountered in the Founders/Meadows structure. CDOT design procedure should be enhanced and made more flexible to employ the proper shear strength parameters of the backfill.
Patent•
1 Aug 2000
TL;DR: In this article, the authors proposed a foundation for supporting a tower-like building structure, in particular for the foundation of a wind turbine or the like, comprising a central portion (1) having supporting means (6) for receiving a tower like building structure and where three or more stabilising members (2) are radially arranged around said central supporting section of the foundation and where each of the stabilizing members provided with ground anchoring means (3) at their peripheral end section.
Abstract: The invention provides a foundation for supporting a tower-like building structure, in particular for the foundation of a wind turbine or the like, comprising a central portion (1) having supporting means (6) for receiving a tower-like building structure, wherein three or more stabilising members (2) are radially arranged around said central supporting section (1) of the foundation and where each of the stabilising members (2) are provided with ground anchoring means (3) at their peripheral end section. Hereby, a reduction of the manufacturing time is achieved just as it is found that a reduction of 50-70 % can be achieved in the amount of material used in the foundation compared with the establishment of a traditional foundation. The extraction and work-up of raw materials, the construction and the transportation are considerably reduced resulting in a less environmentally damaging impact, not only by the use of less material but also less impact due to lower emissions of environmentally damaging substances, i.e. by the combustion of fuel etc. during transportation and manufacturing.
Book•
11 Oct 2000
TL;DR: In this article, a new method is developed which allows to construct accurate and numerical effective absorbing boundary conditions in the frequency domain by uniformly approximating DtN-maps with rational functions.
Abstract: The linear and nonlinear behavior of dams subjected to strong earthquake ground motion is strongly affected by the interaction with the impounding reservoir and foundation. However, when such large systems are analyzed using the finite element method only a small part of the reservoir and foundation, usually called the near field, can be directly modeled. Otherwise, the computa¬ tional costs would be tremendous. In order to avoid the spurious reflection of waves at the artificial boundaries of the finite element model the parts of the reservoir and foundation which are not directly modeled the far field have to be considered by so-called absorbing boundary condi¬ tions. These take into account the dynamics of the far field and especially the phenomena of radia¬ tion damping. In frequency domain, nonlocal absorbing boundary conditions are represented by so called dynamic stiffness functions or DtN-maps. These are numerically very effective for linear prob¬ lems because the simulation can be performed in the frequency domain. However, when nonlin¬ ear effects of the near field should be considered, the simulation has to be carried out in time domain. Then, the coupling of the equations of motion describing the near field with those describing the far field originates a nonlinear system of Volterra integro-differential equations of convolution type. Its numerical solution is very cumbersome because generally large data sets are needed to describe DtN-maps in time domain and because of the huge number of operations being necessary to compute the convolution integrals at every time step. On the other hand, the approximate, local absorbing boundary conditions developed so far for time-domain computations generally require a large near field in order to obtain a sufficiently accurate solution so that these are numerically ineffective when applied to earthquake analysis problems. Moreover, no genuine finite element implementation exists for most of these absor¬ bing boundary conditions. In this work, a new method is developed which allows to construct accurate and numerical effective absorbing boundary conditions. The main idea is to uniformly approximate DtN-maps defined in the frequency domain with rational functions. Within this framework, an DtN-map is considered to be the transfer function of an infinite-dimensional time-invariant linear system. This is approximated with a finite-dimensional linear system. The approximation is performed in two steps. First, the DtN-map kernel is expanded in a series of orthogonal functions (e.g. Laguerre functions). An appropriate Mobius transformation relates this series to a Laurent series. These is truncated after a finite number of terms and identified with a finite-dimensional discretetime system or after a mapping with a finite-dimensional continuous-time system. These sys¬ tems, however, contain many degrees of freedom which have little effect on its input-output behavior so that they can be cancelled without reducing significantly the accuracy of the approx¬ imation. This system reduction is performed using balanced truncation or Hankel norm approxi¬ mation techniques. The absorbing boundary conditions obtained by this novel method are highly accurate approxi¬ mations of DtN-maps. Moreover, these absorbing boundary conditions are always stable and causal. Furthermore, the same technique allows to formulate genuine finite element implementa-
TL;DR: In this paper, a relatively simple method for three-dimensional liquefaction analysis of granular soil under offshore foundations is presented, where the Mohr-Coulomb model is modified to accommodate the plastic strains generated by cyclic loading.
Abstract: This paper presents a relatively simple method for three-dimensional liquefaction analysis of granular soil under offshore foundations. In this method, the Mohr–Coulomb model, which defines the elasto–plastic stress–strain relationship under monotonic loading, is modified to accommodate the plastic strains generated by cyclic loading. The effects of cyclic loading, evaluated from the results of laboratory tests on saturated samples of soil, are incorporated into the model. The method is implemented in an efficient finite element program for analyses of three-dimensional consolidating soil. The practicability of the model is demonstrated by analysis of a typical offshore foundation, and the predictions of the numerical analysis are compared with the observed behaviour of the foundation. Copyright © 2000 John Wiley & Sons, Ltd.
31 Dec 2000
Patent•
30 Aug 2000
TL;DR: In this article, a low impact foundation system is proposed for the preservation of the soil and drainage characteristics of the site upon which it is erected, using small obliquely driven piles in combination with a pre-cast component designed to engage a standard foundation wall.
Abstract: A low impact foundation system requiring little or no excavation, and allowing for the preservation of the soil and drainage characteristics of the site upon which it is erected. The system utilizes small obliquely driven piles in combination with a pre-cast component designed to engage a standard foundation wall.
24 Jul 2000
TL;DR: In this article, the results of a series of full-scale tests performed on deep foundations in liquefiable sand, both before and after ground improvement, where controlled blasting was used to liquefy the soil surrounding the foundations.
Abstract: The results presented in this paper were developed as part of a larger project analyzing the behavior of full-scale laterally loaded piles in liquefied soil, the first full-scale testing of its kind. This paper presents the results of a series of full-scale tests performed on deep foundations in liquefiable sand, both before and after ground improvement, where controlled blasting was used to liquefy the soil surrounding the foundations. Data were collected showing the behavior of laterally loaded piles before and after liquefaction. After the installation of stone columns, the tests were repeated. Based on the results of these tests, it can be concluded that the installation of stone columns can significantly increase the density of the improved ground as indicated by the cone penetration test. The stone columns were found to significantly increase the stiffness of the foundation system, by more than 2.5 to 3.5 times that in the liquefied soil. However, in non-liquefied ground, the improvement from stone columns could be more than compensated for by increasing the piles. In liquefied soil, however, more than doubling the number of piles or increasing shafts diameters by 50 percent did not nearly match the improved performance of the treated ground. This study provides some of the first full-scale quantitative results on the improvement of foundation performance due to stone columns in a liquefiable deposit.