Showing papers on "Foundation (engineering) published in 2001"

Cyclic macro-element for soil–structure interaction: material and geometrical non-linearities

Abstract: This paper presents a non-linear soil–structure interaction (SSI) macro-element for shallow foundation on cohesive soil. The element describes the behaviour in the near field of the foundation under cyclic loading, reproducing the material non-linearities of the soil under the foundation (yielding) as well as the geometrical non-linearities (uplift) at the soil–structure interface. The overall behaviour in the soil and at the interface is reduced to its action on the foundation. The macro-element consists of a non-linear joint element, expressed in generalised variables, i.e. in forces applied to the foundation and in the corresponding displacements. Failure is described by the interaction diagram of the ultimate bearing capacity of the foundation under combined loads. Mechanisms of yielding and uplift are modelled through a global, coupled plasticity–uplift model. The cyclic model is dedicated to modelling the dynamic response of structures subjected to seismic action. Thus, it is especially suited to combined loading developed during this kind of motion. Comparisons of cyclic results obtained from the macro-element and from a FE modelization are shown in order to demonstrate the relevance of the proposed model and its predictive ability. Copyright © 2001 John Wiley & Sons, Ltd.

Offshore wind turbine with floating foundation

Abstract: The invention relates to offshore wind turbines supported on a floating foundation comprising a submerged buoyancy body that is secured to the bottom of the sea by one or more wires etc. By proper design of the buoyancy body and associated wires it is possible according to the invention to restrict and/or control the inclination of the tower of the wind turbine and to maintain the position of the wind turbine on site.

Institutions for sustainability

Abstract: Jointly sponsored by: The Australian Conservation Foundation; The Environment Institute of Australia; Land and Water Australia

Method and apparatus for increasing the capacity and stability of a single-pole tower

Abstract: A support structure for use with an existing single pole tower. The single pole tower has a pole anchored to a foundation and supports a first load. The support structure has a number of sleeves surrounding the pole. A first one of the sleeves is anchored to the foundation. A second load is attached to a second one of the sleeves.

Concrete foundation pierhead and method of lifting a foundation using a jack assembly

Abstract: A method and jacking assembly used for forming a concrete foundation pierhead The pierhead is attached integrally to a foundation and/or floor system A plurality of pierheads are used for leveling the foundation and floor system Each of the pierheads include a jacking assembly which is used for jacking the pierhead on top of a vertical support member The vertical support member may be a helix pipe pier, steel beams, posts, piers and the like The pier pipe is installed into a ground surface and next to the foundation The method steps include excavating a hole next to the foundation and installing the vertical support to a selected depth in the ground surface The jacking assembly is then attached to the foundation and to a top of the vertical support The pierhead is then poured around the jacking assembly and next to the foundation and floor system and allowed to cure A space above the pierhead is provided which is sufficient to allow the jacking assembly to raise the pierhead on the vertical support and in turn raise the foundation and floor system to a level grade

Foundation for a tower and a method for its deployment on site

Abstract: A foundation (20) for a tower (10) is formed of a plurality of prefabricated slabs (24-30,28',29) coupled together so as to function as a monolithic foundation (20).

Modeling of Inelastic Behavior of RC Structures under Seismic Loads

Abstract: Proceedings of the U.S.–Japan Seminar on Post-Peak Behavior of Reinforced Concrete Structures Subjected to Seismic Loads: Recent Advances and Challenges on Analysis and Design, held in Tokyo and Lake Yamanaka, Japan, October 25-29, 1999. Sponsored by the National Science Foundation, U.S.A.; Japan Society for the Promotion of Science; Japan Concrete Institute. This collection presents the latest ideas and findings on the inelastic behavior of reinforced concrete (RC) structures from the analysis and design standpoints. These papers discuss state-of-the-art concrete material models and analysis methods that can be used to simulate and understand the inelastic behavior of RC structures, as well as design issues that can improve the seismic performance of these structures. Topics include modeling of concrete behavior; modeling of RC structures (finite element approach and macro-element approach); and experimental studies, analysis, and design issues.

A Foundation for the Economic Analysis of Software Architectures

Abstract: This position paper is an attempt to show how realoptions theory and portfolio theory—can be applied to making software investment decisions in practice. We have previously developed a method, called CBAM, for making software investment decisions based upon architectural analysis, and have applied this method to a large-scale system development—NASA’s ECS project. Building upon this experience, we reflect upon the relationship between the theory of economic models and what can be done in practice.

Effect of foundation type and compliance on seismic response of rc bridges

Abstract: Foundation compliance appears to be one of the key features of the lateral load response of bridges, but it has not been seen so far as a possible solution to the problem of regulating the response of bridges with piers of unequal height in such a way that a reasonably uniform ductility demand is achieved. The present study focuses on the effect of pile foundation stiffness on the lateral displacements and flexibility of the bridge as a whole as well as on the ductility demand of the pier itself. Conventional lumped plasticity beam models and 2D finite-element models are used for carrying out nonlinear static (pushover) analyses of alternative bridge superstructure systems. The results clearly indicate that the foundation type, the number of piles and their arrangement, and the adopted design approach affect the distribution of ductility demand. It is confirmed that control of the foundation stiffness may be a useful tool for improving the distribution of ductility demand and hence the overall performance of a bridge during strong ground motions.

Grouting for Pile Foundation Improvement

Abstract: The aim of this research was to examine the use of grouting methods for pile foundation improvement, a generic term that is used here to define both foundation renovation (increasing the bearing capacity of a pile foundation that has insufficient bearing capacity) and foundation protection (safeguarding the piles of the foundation against possible damage resulting from underground construction activities in the vicinity) A full-scale test, of which the general set-up and consistency check are outlined in the thesis, examining the feasibility of foundation improvement by means of grouting techniques was conducted in Amsterdam The main part of the thesis focuses on permeation grouting, jet grouting and compaction grouting For each method, first some more general aspects like history, grouting equipment, grouting parameters and fields of application are outlined Subsequently existing theories used in modelling the grouting process are examined and compared The test results are discussed By using the pile displacements, soil stresses, pore pressures and pile bearing capacity measured in the test, it was possible to examine the influence of grouting methods on pile foundations The use of and suitability of geophysical verification methods for grouting, which were necessary to determine the shape and position of grouted elements, were also considered To determine how grouting methods can best be applied for foundation renovation purposes, the cost of grouting methods and the hindrance that they cause have been compared with those of conventional foundation renovation methods The construction cost of grouting can be up to about 50% lower than that of conventional methods of underpinning a structure Taking cost, hindrance and the test results into consideration, it can be concluded that permeation grouting and compaction grouting are economic and effective alternatives to conventional underpinning methods for renovating pile foundations The methods may also be used for pile foundation protection Jet grouting is only suitable for use in the renovation of end bearing piles when the structure is strong and stiff enough to redistribute the loads from the grouted pile Jet grouting is very suitable for use in protecting pile foundations because it can be applied in any type of soil

Laying the foundation.

Abstract: *Pre-AP, AP and Advanced Placement are trademarks of the College Entrance Examination Board. The College Entrance Examination Board was not involved in the production of this material. Laying the Foundation and LTF are trademarks of Laying the Foundation, Inc. MATH Core Training Modules—Year One Participants will explore the AP* Calculus or AP Statistics Connection topics through manipulative-rich student lessons. Graphing calculator skills will be introduced, extended, and applied as a part of each training session. In addition, the participants will explore the LTF on-line diagnostics with both multiple choice and free response problems and will discuss scoring practices and rubrics of Pre-AP* questions related to the AP connection topic. Teachers finish every training day with lessons that are classroom-ready and with sufficient preparation to start using the lessons and assessment tools immediately. Day One Introduction to the LTF Guides through Analysis of Piecewise Functions

Ground-Coupled Heat and Moisture Transfer from Buildings Part 2–Application

Abstract: In this paper the effects of moisture on the heat transfer from two basic types of building foundations, a slab-on-grade and a basement, are examined. A two-dimensional finite element heat and moisture transfer program is used to show the effects of precipitation, soil type, foundation insulation, water table depth, and freezing on the heat transfer from the building foundation. Comparisons are made with a simple heat conduction model to illustrate the dependency of the soil thermal conductivity on moisture content.

Pile design and construction

Abstract: Piles are structural members used to transfer loads through water or ground of low strength to a competent bearing stratum. Piles may be either driven (displacement) or bored (non-displacement), and either preformed (steel tube or section, wood, reinforced or prestressed concrete) or cast-in-place (in situ concrete). They may be ‘end bearing piles’ (i.e. deriving their carrying capacity from resistance of the point embedded in strong soil or rock) or ‘friction piles’ (i.e. deriving their carrying capacity from adhesion between the pile shaft and the surrounding ground) or a combination of these factors. The criteria for a successful pile are geometry, tolerance, constructability, durability, and structural efficiency. The philosophy behind this thesis has been to develop an up-to-date collection of the current design and construction practices of piling engineering, focused towards developing a model that can be used for future reference. In order to achieve this, extensive research and consultation with industry, as well as literature detailing foundation construction methods has been undertaken. It was desired to gain an appreciation of the general holistic approach to pile foundations, and cover some innovative methods used. This allows an understanding of how to approach a problem in a realistic manner. The report also covers potential problems and uncertainties with pile design and construction. This thesis is a comprehensive review of pile foundations. The report draws together design techniques, performance criteria, methods of installation, economics, and selection of piles. This thesis provides an easy-to understand, extensive, and integrated analysis of the behaviour, design, and construction of piles. It is intended as an educational tool, not as an end in itself; therefore, the document has been designed to foster the study, research, and comprehension of piles.

Water-retaining structure

Abstract: Device for retaining water comprising a foundation (3), a retaining wall (1) movably attached to the foundation (3) and a shore (5)movably, particularly hingingly, attached to the foundation (3), in which the shore (5) and the retaining wall (1) are movably, particularly hingingly, attached to each other, and in which the retaining wall (1) is provided with at least an internal longitudinal hinge (2a, 2b) about which the retaining wall can be turned.

Expansive Clay Soils and Vegetative Influence on Shallow Foundations

Abstract: Proceedings of geotechnical sessions at the 2001 Annual Civil Engineering Conference, held in Houston, Texas, October 10-13, 2001. Sponsored by the Shallow Foundation and Soil Properties Committee of the Geo-Institute of ASCE. This Geotechnical Special Publication contains 14 papers that discuss the effects of trees and moisture movements on various lightly loaded foundations on expansive clays. Papers review current state of the practice in foundation design, maintenance, and remediation as it relates to vegetative effects and expansive clays on foundations. Topics include: tree root damage to buildings; predicting volume changes in expansive soils resulting from environmental factors including vegetation; drought; expansive clay soil problems and solutions throughout the world; soil-structure interaction; field test program to obtain geotechnical properties; depth of wetting and active zone in expansive soils; slabs on expansive clay with vegetation considerations; volume change coefficient of expansive clay; in-situ modification of active clays for shallow foundation remediation; cracking of pavement due to drying shrinkage; soil suction measurements; and data base on under-slab moisture contents in Texas.

Method and apparatus for forming a concrete foundation wall

Abstract: A method and apparatus for forming a concrete foundation wall. A trench is opened in the ground and a form is inserted into the trench. The form is made up of a pair of spaced-apart opposing panels, which define a cavity. The panels may be made of a thermal insulating material, which may be extruded foam insulation or, more particularly, extruded polystyrene. The panels may be supported through a combination of J-channels, spreader brackets, connecting members, and a support member. The method further includes backfilling the trench around the form with dirt and pouring concrete into the cavity. The dirt provides support for the form as the concrete is poured.

Fixed location positioning of functional units on or in water

Abstract: The apparatus is used to fix functional structures such as wind power systems, light towers, radio towers etc on or in water, especially on or in the sea. The apparatus has at least one buoyancy body (14) as a foundation or platform for the functional unit, This body is preferably hollow. The buoyancy body is held in place at a predetermined depth of water by an anchor (16) which has its own characteristic buoyancy in water.

Evaluation of ground and building settlement near braced excavation sites by model testing

Abstract: Braced excavations inevitably result in deformation of the adjacent ground and settlement of adjacent buildings behind the wall. Building settlement is believed to exceed the amount of associated ground settlement be- cause of the additional settlement under building weight. This is due to a decrease in stiffness of the foundation soil that is caused by lateral movement of the excavation face. To quantify the amount of building settlement, model testing was conducted to determine the magnitude of the additional settlement due to the structure and the effect of varying the building's depth in the ground and of its distance away from the excavation wall. The building's settlement, when at ground level, was found to be up to 500% more than that of ground with no structure on it. This is for the case when the building's centroid on the ground surface is located within Rankine's active zone. When the building was embedded in the ground the degree of additional settlement decreases very rapidly, becoming negligible if the building is embedded at more than one half of the excavation depth. Additional model testing was conducted to estimate the extent of the soil improvement zone required to protect structures adjacent to an excavation. From the model testing results, soil improvement should be performed to reduce building settlement when the building's centroid is located in the excavation influence zone. The zone for this soil improvement is determined by setting the distance away from the excavation wall to be equal to the depth of the excavation.