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By Han Jie

The results of full scale plate load tests on stone columns on soft clay in coastal areas are presented in this paper. Four load tests were made, two of which were performed on the ground treated with stone columns, one on an isolated stone column and the last one on the untreated ground. For a given stress range, the settlement of the rigid plate, the stress concentration factor, and the excess pore water pressure were measured. It is found that the distribution of vertical stress beneath the rigid plate supported by the composite ground of stone columns is very different in shape from the one by the untreated ground, that the stress concentration factor has a relation with the stress level and time, that the stone columns increase the bearing capacity up to by 2 times, and that the ground stabilized by stone columns is of great advantage to keep the foundation stable.

Jan 1, 1991

By M. Y. Xia

In this paper, based on the Theological tests of the interface between clay and concrete, an interface Theological model is proposed and is used in the finite element analysis which takes soil as viscoelastic mass and Theological effect of the interface between diaphram wall and ground into consideration. Its results are compared with those without an interface element, without considering the relative creep displacement. Close attention is paid to the variation of wall with time under the condition of various interface shear stiffness and viscous sliding coefficient, and their effects on the wall bending moment are primarily verified in the paper. The change of wall bending moment with time, trench heave and wall displacement in different excavation depth, bracing position, parameters for soil are also studied.

Jan 1, 2010

By William Auyeung

Micro-piles are small-diameter, drilled and grouted reinforced piles used for both structural support and in situ earth reinforcement. They were conceived in Italy in 1952, but have become popular in Canada and the United State only since the mid-1980s. The Province of British Columbia completed a construction of a 265-km (165 miles) four-lane highway between Campbell River and Victoria in the year of 2000. The construction of Big Qualicum Bridge was part of the above mentioned provincial government project and this bridge was made of twin cast-in-place concrete parabolic arch structures. The overall length of the bridge is 261 metres (856 feet) and the width is 24.2 metres (80 feet). The massive thrust from each arch is resisted by groups of 46 drilled micro-piles that are about 230 mm (9 inches) in diameter with No. 18 high strength Dywidag threaded bars with double corrosion protection up to 15 metres (50 feet) long. This paper will describe the micro-pile design and installation methods. The performance of the micro-piles in full scale testing in tension and compression monitored with electronic strain gauges will be presented. The impact of drilling methods on the performance of the micro-piles will also be discussed.

Jan 1, 2004

By Ronald E. Walkington

The U.S. Department of Energy (DOE) is building the world's newest accelerator-based, pulsed-neutron system, called Spallation Neutron Source (SNS). The facility, located in Oak Ridge, Tennessee, is a partnership of six DOE national laboratories - Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge. Oak Ridge has the responsibility for managing the partnership and ultimately operating SNS. SNS will provide opportunities for up to 2,000 researchers each year from universities, national laboratories and industry from around the world for basic and applied research and technology development in the fields of materials science, magnetic materials, polymers and complex fluids, chemistry and biology. When completed, this state-of-the-art research facility will provide neutron beams that are 12 times more intense than any other such source in the world. Most of the world's neutron sources were built decades ago. Therefore, it is easy to understand how SNS will provide new research opportunities unavailable elsewhere, and at the same time restore United States leadership in neutron sciences. Neutron scattering research provides valuable information about materials that cannot be obtained through microscopy, X-rays, spectroscopes, or other techniques. The information gained from neutron scattering research leads to improved materials that are used in high-temperature superconductors, powerful lightweight magnets, aluminum bridge decks, jet aircraft, compact and computer discs, magnetic recording tapes, shatter-proof windshields, and many other applications. SNS is like a flashing strobe light providing high-speed illumination of an object and will record the structure of physical and biological materials from plastics to proteins. Because neutrons have no charge, they can penetrate more deeply into materials than do X-rays, light, or electrons and thus reveal bulk structure and properties of materials. SNS will help to understand and "engineer" better materials and the manufacture of better products at the atomic level. Our high-technology society demands new materials that are stronger, lighter, and cheaper yet perform well under severe conditions. SNS, which is designed with the future in mind, will be the leading neutron research facility for many years to come.

Jan 1, 2001

By A. Le Kouby

We present in this paper the results of a parametric study carried out in a calibration chamber on instrumented model piles. The aim is to point out group effect on piles within a group through their resulting shaft friction and tip resistance. The methodology relies on the study of the influence of adjacent piles on a "reference" pile. The soil used is a silica sand (Fontainebleau sand). The influence of parameters like pile spacing, number of piles and installation order are evaluated. The results show a positive effect on shaft friction of the group effect and a negative effect on tip resistance. Efficiency factors are defined in order to have a better view on the parameters influencing the response of the pile within a group.

Jan 1, 2006

By K. C. Foye

Use of load and resistance factor design (LRFD) of foundations is growing, from offshore applications to bridge applications and beyond. The development of load and resistance factors for design has traditionally relied on calibration to traditional factors of safety. This technique, however, offers little insight into the challenges of pile design. This paper discusses an approach to LRFD factor development that seeks to isolate the various sources of design uncertainty. Using this approach, reliability analysis is used to develop resistance factors for the design of driven pipe piles in sand. These findings shed light on many aspects of the ongoing discussion of how LRFD can be successfully applied to pile design.

Jan 1, 2008

By S. L. Karunakaran

There are cases where it is found that a raft foundation would have adequate factor of safety against ultimate bearing capacity failure but the settlements would be excessive. Piles may be introduced in order to limit settlements to an acceptable level. The actual number of piles required to reduce the settlements to an acceptable level may be very small compared to the number of piles required to transmit the whole structure load. The paper focuses on the difficulties encountered in evaluating the load sharing between raft and piles. An elaborate analysis taking into account the interaction between raft, piles and soil is very complex and time consuming. Few approximate methods for arriving at a satisfactory solution to piled raft system are discussed in the present paper.

Jan 1, 1996

By Hajialilue Bonab M.

The soil-pile interaction under lateral impact loads is not yet completely well known. Many tests on single piles under static lateral loads in centrifuge have been performed and P-y curves have been determined at different levels of the pile in soil. Following these static tests on piles, a large program is undertaken with the same piles submitted to impact loads. The pile equipped with various pile caps has been impacted under variable amplitudes of shock. The behavior of the pile under different impacts was studied and dynamic parameters of the soil-pile system have been determined. Many cases of loading constituting various load histories have been analyzed. They are resulting from parametric centrifuge tests run out, on the one hand with constant and cumulative impacts and on the other hand, variable and cumulative ones. The Influence of each type of loading was studied. Using a finite element method, a non-linear pile-soil system was conceived and a transient dynamic analysis have been performed. The results of the non-linear analysis and experimental data were compared giving a good agreement.

Jan 1, 2002

By Subrata Ray

A large no of power stations are being set up in Chandrapur area having coal deposits. Several industries are also coning up in this area. The subsurface is geologically formed under Gondwana system and consists of shale strata at depths ranging from 8 to 12 m. The stress deformation characteristics of shale exhibits wide variation because of it's geological origin. In view of this, a study was conducted on bored cast in-situ piles installed for a Switch yard project to evaluate load settlement characteristics of three test piles to understand the probable engineering behaviour of the material at the tip and the sides. An approach is developed to simulate the load settlement behaviour as observed in the field, theoretically. This is based on the concept of load transfer. The fit is obtained by varying the parameters, thus may be considered as iterative in nature. The theoretical curves closely matched the observed curves. The results of this study are presented in this paper.

Jan 1, 1996

By Madhira R. Madhav

In an alluvial deposit consisting of layers of sandy silt with clay and kankar nodules, driven cast in situ piles are provided. The piles end on a stiff bearing stratum To verify the available design capacities, compression, pull-out and lateral load tests are conducted in situ. The elastic continuum approach is used to estimate the equivalent modulus of deformation of the deposit. A comparison is made of the values from the three types of tests.

Jan 1, 1996

By Willie M. NeSmith

In the Metropolitan Atlanta Area today, augered, cast-in-place (ACIP) piles will be considered on most projects where deep foundation support is required. ACIP piles were first used in Atlanta in the late 1960s, and application began to blossom in the mid-1980s. Current design practice for ACIP piles is addressed in another paper in this conference. This paper describes the evolution of the ACIP industry in Atlanta, and details the use of ACIP piles on major projects in the Atlanta area.

Jan 1, 2003

By A. A. Gupte

Auger piling system which was developed in the United States in the 1940's is gaining acceptance in many parts of the world. Although primarily used to support foundations, the system is very useful for many other applications such as soil anchors, temporary and permanent earth retention systems, restricted headroom piling and underpinning of existing foundations. In this paper, review of current construction design techniques for the Auger piling system for earth retention and underpinning of structures is presented.

Jan 1, 1989

By V. T. Ganpule

The effect of Sulphate and Chloride is well understood by the engineers. Most of the codes stipulate permissible limits for sulphate and chloride content in groundwater. Relatively few reference are available about the effect of organic acids on pile concrete. While executing a pile foundation work around Bombay, the authors came across the peculiar phenomenon. The routine testing of water has indicated that water is non-aggressive; however, on exposing the piles, the piles were found to be highly detonated. The testing of water on the guidelines followed by engineers associated with flow through pipes revealed that water is corrosive as per the Ryznar index concept. The present papers discussess the significance of Ryznar index in under water concreting.

Jan 1, 1996

By Wang Huichang

A tentative mathod for predicting load-settlement relationship and bearing capacity of single piles based directly on the results measured by cone penetrometer with local friction sleeve is presented. It is possible that the load-settlement curves can be constructed by means of CPT and the problem of both the bearing capacity and the settlement behaviour of single piles can be considered jointly. The proposed load-transfer functions are continuous, positive monotonic and nonlinear. a concept of weight mean point resistance 2D above and 4D underneath the pile base to determine the unit ultimate base resistance of piles is presented. The predicted results of seven jacked piles in loess are in good agreement with the load test data.

Jan 1, 1991

By A. Ghorbani

The analysis of Combined Pile Raft Foundation (CPRF) is very complex due to involved interactions among components of CPRF system. Many researchers made efforts to develop sufficient methods including three dimensional finite element methods to compute these interactions. Since there are some restrictions and complexity in previous methods, in present study a new approach based on three dimensional finite difference methods is implemented to overcome some of these restrictions. The total and differential settlements of a centrifuge case study are computed using different numerical methods to show the performance of present numerical approach.

Jan 1, 2007

By Safwan Labanieh

An experimental set-up is specially designed to study the behavior of a friction pile of 3 cm diameter in contact with the soft clay of Mexico City in a small calibration chamber (CC) of 30 cm diameter and 50 cm height. The consolidation of this compressible clay is accomplished using a special system adapted to the CC itself to insure a good knowledge of the initial state. Loading results of the pile under a consolidation pressure of 50 kPa indicate an elastic mobilization of shear stresses at the shaft of the pile (?3 kPa for 1mm displacement) followed by a hardening plastic type behavior. Unloading-reloading results indicate a mobilization of shear stresses of the same type and of the same order of values obtained from the virgin loading stress path. Cyclic loading (?40 cycles) between 0 and 1 kPa (1/3 of the failure value) give similar results to those obtained from virgin loading.

Jan 1, 2002

By P. Middendorp, Gerald E. H. Verbeek

"INTRODUCTIONStatic Load Testing (SLT) is generally considered the pile testing method that provides the de-facto answers regarding pile capacity and load-deflection behavior. However, as this testing method is time consuming and costly, alternative pile testing methods are applied, such as High-Strain Dynamic Testing (HSDT), commonly referred to as Dynamic Load Testing (DLT), and Rapid Load Testing (RLT), which includes Statnamic Testing (STN) and the Fundex Pile Load Tester (PLT). Extensive descriptions of these pile testing methods as well as comparisons of the results from these two methods have been widely published, but little is written on the choice between HSDT and RLT. This article will address this issue for concrete piles by discussing five different aspects that should be considered when making a choice between HSDT and RLT for either cast-in-situ piles or precast driven piles. TIMINGThe timing of the pile load test is independent of the testing method. For cast-in-situ piles load testing is performed some time after the pile has been installed (to allow the pile to obtain the compressive strength required to withstand the test load), while for precast driven piles load testing is performed after a so-called set-up period following pile installation (to allow the soil to recover from driving induced disturbances and, at least in most cases,regain strength).In other words, the timing of the test does not affect the choice of the testing method.ACCURACY OF THE APPLIED LOADWhen a pile is tested by RLT the applied load is measured by a calibrated load cell placed on the pile head, just as it would be during SLT. This means that the error in the applied load value is less than 0.1% of the maximum range of the load cell.However, when a pile is tested by HSDT the load is calculated from the measured strains, which means that the outcome is dependent on the pile material properties. In this case the applied load (F) on the pile head is calculated by multiplying the measured strain (?) with either the calculated or estimated elastic modulus of concrete (E) and the pile cross section (A).The elastic modulus is generally back calculated from the (average) stress wave velocity (c), which in turn is derived from the reflection time (T) it takes for a stress wave to travel over the pile length (L) from the pile head to the pile toe and back to the pile head."

Jan 1, 2006

By R. Paul De Bruyn

A. Crane Check List -- Make -- Model -- Year of Manufacture -- Where is load chart? Is it for this crane? -- Boom style and length -- Boom tip drawing (sketch) for fixed lead connection. Has the crane manufacturer been consulted on the point of attachment? -- How many drums; diameter and length of wire rope. -- Is the single part line pull enough to lift pile or hammer on single part line? -- What is the effective weight of the whole driving system - leads, pile, hammer, etc? -- Are there any auxilliary hydraulic systems? Are the line pulls on these adequate to lift the pile or hammer? -- What is the anticipated working radius? Will the spotter collapse to that length? -- Nature of foundation under crane - barge, marsh, unstable sand, etc. -- Does the crane meet OSAH and state regulations -current certification. Note - the operator is responsible for compliance with regulations. -- Is there any extra weight added to counterweight by compressors or hydraulic systems? What does crane manufacturer say? Consult factory before adding.

Jan 1, 1990

By Gerald Verbeek

There are certain concepts that seem to invite responses from some, including some in the foundation industry and even some within DFI, that are at best surprising. Business owners and their employees share the desire that their company does well and continues to operate. Maybe company growth is not always realistic but maintaining the current level of activity is in the least what they hope for. In other words, they hope that their company is sustainable, and they are fully behind that notion. But when the concept of sustainability is raised, there is, at least with some, suddenly doubt that that is a good thing. And yet, that concept only aims to achieve at a grander scale what the owners and employees desire for their company. There are many definitions of the term sustainability, but probably the most commonly used description is that framed by the United Nations in 1987. It states that sustainability is the concept of meeting the needs of the present without compromising the ability of future generations to meet their own needs. Arguably that definition is too abstract and does not provide the type of specific goals and targets we are used to. To help with that, to some extent, in 2015 the United Nations formulated 17 Sustainable Development Goals (SDGs), to provide "a shared blueprint for peace and prosperity for people and the planet, now and into the future." And undoubtedly those SDGs are fodder for those that question the concept of sustainability in the foundation industry. How can our industry, they wonder, ensure that there is no poverty or hunger (SDG 1 and 2), and the climate action goal (SDG 13) immediately leads to the hot button topic of global warming. And maybe this is where advocates lose (some of) the sceptics of the sustainability concept, but hopefully they will continue to read this article that lays out why sustainability simply makes sense, also for the foundation industry and especially for DFI.

Nov 1, 2022

By C. N. Baker

The design and construction of drilled piers through water bearing and caving soil conditions are discussed. The need for close cooperation between the design engineer and contractor in both the design and construction stage is outlined. Four case histories illustrating the design and construction considerations for four different problem soil and ground water profiles are presented, including the field testing and observation procedures that were utilized to confirm that the design inten. was accomplished. Requirements advisable when placing concrete under water in a cased environment and when placing concrete under slurry in an uncased environment are described.

Jan 1, 2010