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Order No: AAC NN90555 ProQuest - Dissertation Abstracts

Title: NONLINEAR ANALYSIS OF PILES WITH APPLICATION OF OFFSHORE

TOWER RESPONSE

Author: EL NAGGER, MOHAMED HESHAM HAMED

School: THE UNIVERSITY OF WESTERN ONTARIO (CANADA) (0784)

Degree: PHD Date: 1994 pp: 270

Advisor: NOVAK, MILOS

Source: DAI-B 55/09, p. 4018, Mar 1995

Subject: ENGINEERING, CIVIL (0543)

ISBN: 0-315-90555-7

Abstract: Three main areas are addressed in this study: (1) Statnamic test analysis. In recent years a new type of pile test employing a short-duration load was developed that became known as pile Statnamic test. A method of dynamic analysis has been formulated for this test. The aim of the analysis is twofold: to calculate the pile head displacements in such a way that a satisfactory match with the data measured during the test is obtained\; and using the model parameters established from this comparison to predict the pile capacity. The model is one-dimensional and accounts for slip and energy dissipation in the far field. The parameters of the model are, for the most part, directly related to standard geotechnical parameters. The case studies described in this research indicate that the proposed mathematical model works very well and that the Statnamic test may become a useful tool for pile capacity prediction.

(2) Nonlinear behavior of piles. An analysis of pile axial and lateral response to transient dynamic loading and to harmonic loading is presented allowing for nonlinear soil behavior, energy dissipation through radiation damping, soil hysteresis, and the loading rate dependency of the soil resistance. Furthermore, the discontinuity conditions at the pile-soil interface are accounted for. In addition, the effect of neighbouring piles is taken into account for piles in a group. The approach is employed to analyze the pile response to harmonic forces, pile driving, and Statnamic loading and to establish the bearing Capacity and load-deflection curves. Equivalent linear stiffness and damping parameters as well as interaction factors for approximate nonlinear analysis of pile groups are established and presented.

(3) Effect of foundation nonlinearity on offshore tower response. The response of a fixed offshore tower is greatly affected by the nonlinear behavior of the supporting piles. The nonlinear analysis developed in this study is utilized to model the response of foundation piles. A model for the evaluation of wave forces on the tower members that takes into account the spatial incoherence effect on wave forces is described and used in the analysis. The effect of different foundation parameters on the dynamic characteristics of the tower is investigated. Also, the tower response to random wave forces is conducted and the effect of foundation parameters on the tower response is examined. The dynamic characteristics of the tower and its response to wave forces were found to be greatly influenced by the foundation nonlinearity and by the pile-soil-pile interaction as well.

Order No: AAC NN90574 ProQuest - Dissertation Abstracts

Title: DYNAMIC ANALYSIS OF SINGLE PILES AND PILE GROUPS (SOIL

PROFILES)

Author: EL-MARSAFAWI, HAZEM GAMAL

School: THE UNIVERSITY OF WESTERN ONTARIO (CANADA) (0784)

Degree: PHD Date: 1994 pp: 251

Advisor: NOVAK, M.

Source: DAI-B 55/09, p. 4018, Mar 1995

Subject: ENGINEERING, CIVIL (0543)

ISBN: 0-315-90574-3

Abstract: The determination of stiffness and damping of piles is an important step in the analysis of pile-supported structures subjected to dynamic loading.

The first part of this study examines the use of approximate methods to evaluate the impedance functions of single piles and pile groups. The group impedances derived from the superposition of the two-pile solution are compared with those obtained from direct analysis. Good agreement is observed for floating piles in homogeneous and nonhomogeneous soil profiles. An extensive set of dynamic pile-soil-pile interaction factors is presented in a form suitable for interpolation. An approximate approach for the evaluation of pile-group impedances is proposed. The approach is based on combining the single-pile solution with curve-fitted expressions of the interaction factors.

In the second part of the study, field experiments are conducted to evaluate the response of a single pile and a pile group to harmonic loading. The experimental results are compared to the theoretical predictions of the linear theory. The comparisons indicate that the theory provides a good estimate of the single-pile and pile-group stiffness. However, the damping is significantly overestimated.

The third part of the study investigates the effects of separation and slippage at the pile-soil interface on the stiffness and damping parameters. A semi-analytical frequency-domain analysis and a time-domain boundary-element formulation are presented. Approximate corrections to the linear theory are suggested in order to include the effect of confining pressure and displacement amplitude on response predictions.

Order No: AAC NN90578 ProQuest - Dissertation Abstracts

Title: DYNAMIC ANALYSIS OF TURBINE-GENERATOR-FOUNDATION SYSTEMS

Author: LIU, WEIMING

School: THE UNIVERSITY OF WESTERN ONTARIO (CANADA) (0784)

Degree: PHD Date: 1994 pp: 297

Advisor: NOVAK, M.

Source: DAI-B 55/09, p. 4021, Mar 1995

Subject: ENGINEERING, CIVIL (0543)

ISBN: 0-315-90578-6

Abstract: In this dissertation a comprehensive investigation on the dynamic characteristics of turbine-generator-foundation systems is performed. All the major components of the system, including turbine-generator casing, shaft, rotors, journal bearings, deck, piers, foundation mat, piles, and soil medium, have been included. Full interaction between the turbine-generator set, the foundation superstructure, and the soil medium, is considered.

A hybrid method is proposed to establish the mathematical model for the turbine-generator-foundation system, which includes finite element discretization of turbine-generator and foundation superstructure, combined with a soil stiffness matrix derived from the dynamic Green functions of the soil. The soil is modeled as a transversely isotropic layered medium over a rigid bedrock. The analysis is conducted in frequency domain through complex frequency response analysis. The response in time domain is obtained by Fourier transform. The seismic excitation is represented as the control motion on the ground surface, which is generated as an artificial earthquake. Both inertial and kinematic interactions are included.

Several computer programs, including a general purpose finite element program, a program to formulate soil stiffness matrices, and a program to generate artificial earthquake ground motion records, have been written by the author, which can be used to analyze most soil-structure interaction problems, such as machine foundations, buildings, piles and pile groups, tunnels, and dams. A series of parametric studies on strip foundations, single piles, pile groups, and three-dimensional mat foundations is presented to demonstrate these applications. Particular attention is paid to the effect of soil anisotropy on the structural response. The effect of soil anisotropy on the foundation response is found to be significant in most cases.

A 300MW turbine-generator-foundation system is analyzed as an application of the developed mathematical model and computer codes. Excitations from rotor unbalances and earthquakes are considered. The influence of turbine-generator casing and soil anisotropy on the response of the system is explored. It is found that the presence of casing and soil anisotropy strongly influences the displacements and internal forces of the system under rotor unbalance excitation. Under seismic excitation, however, although the presence of casing and soil anisotropy does affect the displacements of the system, their effect on the internal forces of the system is minimal.

Order No: AAC 9432639 ProQuest - Dissertation Abstracts

Title: LATWAK: AN IMPACT TEST TO OBTAIN THE LATERAL STATIC

STIFFNESS OF PILES

Author: BALLOUZ, MARC YOUSSEF

School: TEXAS A&M UNIVERSITY (0803) Degree: PHD Date: 1994

pp: 261

Advisor: BRIAUD, JEAN-LOUIS

Source: DAI-B 55/07, p. 2893, Jan 1995

Subject: ENGINEERING, CIVIL (0543)

Abstract: This study presents the development and application of a new method to predict lateral static stiffness of piles. This new method is called LATWAK\; it consists of a package including the LATWAK Test, the theory behind it, and the LATWAK computer program.

The LATWAK Test allows to obtain time dependent data by hitting the top of a pile laterally with a sledge hammer\; the hammer is instrumented with a dynamic force transducer and the pile is instrumented with a geophone. The horizontal force vs. time signal is the input and the horizontal velocity vs. time signal is the response. The pile is modeled as an elastic member inserted in a visco-elastic soil. The theory of flexural waves, applied to the assumed pile model, allows to determine the theoretical mobility of the pile head in question. Also, Discrete Fourier Transforms, DFT, applied to the time domain data given by the LATWAK test, allow to determine the measured mobility of the pile head. The System Identification Technique is employed in order to match the measured and theoretical mobility curves, thus predicting all the parameters of the assumed soil/pile model. One of the predicted parameters, the element soil spring stiffness, directly relates to the lateral static stiffness at the pile head, which can thereby be predicted.

The "LATWAK" computer program was specifically developed in this study in order to automate the theoretical and the data analyses. Many features can be found in this program. The main capabilities of the program are to visually simulate the pile wave motion, obtain the theoretical mobility response, retrieve the LATWAK test data and transform them into the measured mobility response, as well as match the two curves, identify the system, and predict the lateral static stiffness.

In this study, both conventional static load tests and LATWAK tests were conducted on twenty full scale piles at three different sites. LATWAK predictions of lateral static stiffness were found, on the average, to fall within 25% of those measured conventionally by much more expensive lateral load tests.

Order No: AAC 9431460 ProQuest - Dissertation Abstracts

Title: EXPERIMENTAL STUDY OF ULTIMATE UPLIFT RESISTANCE OF

ROUGHENED MODEL PILES IN SAND

Author: SHLASH, AHMED

School: THE UNIVERSITY OF WISCONSIN - MADISON (0262) Degree: PHD

Date: 1994 pp: 386

Advisor: EDIL, TUNCER B.

Source: DAI-B 55/07, p. 2905, Jan 1995

Subject: ENGINEERING, CIVIL (0543)

Abstract: The main thrust of this study is an experimental investigation of the ultimate shaft resistance of rough piles in sand. Two model steel pipe piles (outside diameter of 1.75 and 3.5 inches) were instrumented each with six electrical resistance strain gages and were calibrated under axial compressive loading as well as lateral pressure. The model piles were made rough by gluing sand on their outer surfaces. In order to assess the effects of initial sand density and pile placement method on the ultimate shaft resistance and displacement of rough piles in sand, the model piles were installed in loose and dense sand using three methods of pile placement (driving, jacking and a reference method with minimum sand displacement and disturbance termed undisturbed method). The uplift tests on the model piles were conducted in a large test pit (10 x 10 x 10 ft). The outcomes of the tests were analyzed statistically. The results of the statistical analysis indicated that initial sand density is the most significant factor affecting shaft resistance of rough pile in sand followed by pile placement method.

The internal axial loads in the model piles were initially calculated from the measured longitudinal and circumferential strains at ultimate uplift referenced to those before uplift loading using the calibration data of the model piles directly. The calculated axial loads indicated the existence of significant tensile loads at the pile tip (in some cases greater than 45% of the measured ultimate uplift load) implying the existence of some residual loads locked in the piles after placement. The calculated internal axial loads using this method were termed "apparent axial loads". The apparent axial load distributions which are widely used in geotechnical engineering lead, in most cases, to misleading conclusions regarding the unit skin friction distribution along piles in sand since they contain contribution not only from the applied uplift load, but also from residual loads locked in the piles during installation. To quantify residual loads induced by pile placement method, the Hunter and Davisson (1969) method was used.

The true internal axial load distributions along the model piles were obtained by correcting the apparent loads to account for residual loads and the load transfer analysis was performed on the basis of the true distributions instead of the apparent ones. The results showed that the variation of the true axial loads along the model piles in dense sand is essentially parabolic suggesting a linear variation of unit shaft resistance with depth. On the other hand, the variation of shaft resistance along piles in loose sand and in most cases was found to increase with depth parabolically at a decreasing rate and reach a maximum limiting value at a normalized depth, z/B (B = pile diameter) which varies between 14 and 35 depending on pile placement method, pile size and surface roughness. Beyond this normalized depth, the unit shaft resistance stabilizes with depth. (Abstract shortened by UMI.)

Order No: AAC 9419941 ProQuest - Dissertation Abstracts

Title: EFFECT OF CEMENTATION ON CONE RESISTANCE IN SANDS: A

CALIBRATION CHAMBER STUDY

Author: PUPPALA, ANAND JAGADEESH

School: THE LOUISIANA STATE UNIVERSITY AND AGRICULTURAL AND

MECHANICAL COL. (0107) Degree: PHD Date: 1993 pp: 383

Advisor: ACAR, YALCIN B.\; TUMAY, MEHMET T.

Source: DAI-B 55/03, p. 1067, Sep 1994

Subject: ENGINEERING, CIVIL (0543)\; GEOTECHNOLOGY (0428)

Abstract: An understanding of the effect of cementation on geotechnical properties of soil deposits is gaining increasing attention in the profession. When low levels of cementation in sands are neglected, pile capacity and slope stability are underestimated and liquefaction is overestimated. It is essential to devise schemes to identify cementation in soil investigations and develop methods in evaluating engineering characteristics of cemented deposits. The objective of this study is to develop a method to identify cementation in sands and assess the engineering characteristics of cemented sand deposits using the cone penetration testing scheme.

The scope of the study includes evaluation of the effect of cementation on cone penetration testing (experimental model) and comparison of these experimental results with theoretical models of penetration mechanism in cemented sands. Existing models based upon the bearing capacity theories and cavity expansion models are utilized in theoretical modeling. A constitutive model is developed for strength-deformation behavior of cemented sands and is used in theoretical modeling.

Artificially cemented Monterey No. 0/30 is used in the calibration chamber study. A total of 30 tests are conducted at three ranges of relative density (45-55, 65-75 and above 85%), three confining pressures (100, 200 and 300 kPa) and three different cement content (0, 1 and 2%). Pluviation method is used for specimen preparation. Specimens are cured for 7 days, transferred into the flexible wall calibration chamber and then consolidated under $K\sb0$ conditions. Penetration testing was conducted with a 1.27 cm diameter miniature cone. Separate drained triaxial tests provided the necessary parameters for strength-deformation modeling of cemented sands.

The experimental model results coupled with the theoretical model predictions provide a semi-empirical and empirical schemes for evaluating engineering characteristics of cemented sand deposits. An assessment of the applicability of these models in prediction of cementation in such deposits is also provided. The results indicate that tip resistance and sleeve friction in cone penetration testing provide a reasonable assessment of cementation. The charts and the analysis method provided can be used to estimate the engineering characteristics of such deposits.

Order No: AAC 1356290 ProQuest - Dissertation Abstracts

Title: PORE PRESSURE BUILD-UP AND DISSIPATION AROUND PILES

PENETRATING IN CLAYS

Author: MYNAMPATY, RAVINDRA NARASIMHA

School: UNIVERSITY OF LOWELL (0111) Degree: MS Date: 1993

pp: 190

Advisor: PAIKOWSKY, SAMUEL G.

Source: MAI 32/04, p. 1205, Aug 1994

Subject: ENGINEERING, CIVIL (0543)\; GEOTECHNOLOGY (0428)

Abstract: This investigation of pore pressure behavior was undertaken in order to acquire a better understanding of time effects on pile foundations in clay. Typical initial excess pore pressure distributions, and their dissipation patterns, possibly as a function of the soil overconsolidation ratio (OCR) and/or confining pressure, were examined.

Two data sets of pore pressure measurements around piles were gathered at the University of Massachusetts, Lowell.

There is a zone of disturbance around the full-scale/model pile tip which leads to generation of higher excess pore pressures. The excess pore pressures measured at a distance of greater than 17 pile radii from the tip of the full-scale/model pile are more representative of steady state conditions. The relationship of the shaft's steady state pore pressures with OCR was found to be different than that observed for the pore pressure measured at the tip.

Analysis of the dissipation data yielded a clear pattern of higher OCRs leading to faster dissipation times for Boston Blue Clay. (Abstract shortened by UMI.)

Order No: AAC 1352648 ProQuest - Dissertation Abstracts

Title: A SIMPLIFIED FIELD METHOD FOR THE CAPACITY EVALUATION OF

DRIVEN PILES

Author: REGAN, JOHN ERIC

School: UNIVERSITY OF LOWELL (0111) Degree: MS Date: 1993

pp: 286

Advisor: PAIKOWSKY, SAMUEL G.

Source: MAI 32/01, p. 301, Feb 1994

Subject: ENGINEERING, CIVIL (0543)\; GEOTECHNOLOGY (0428)

Abstract: Dynamic analyses of piles are methods aimed at the prediction of pile behavior under static loads based on the pile response during installation.

Two methods are currently employed for the analysis of the measured data. One, an office analysis, utilizes a numerical solution of a mathematical model for the pile-soil system. The other, a field analysis, provides an instantaneous evaluation of the pile capacity following each hammer blow.

Substantial experience suggests the existence of major limitations to the field method.

A simplified method based on energy balance is proposed as an alternative field method.

The results of the presented study invalidate the concept of a "unique" recommended correlation between the viscous damping and soil type in both wave-based analyses. It is shown that energy losses should be attributed more to soil inertia rather than soil damping.

The Energy Approach method was found to provide excellent evaluations of pile capacity. The method is therefore proposed to be used in the field. The predictions of this method were found on the average to provide more accurate evaluations than the sophisticated office methods. (Abstract shortened by UMI.)

Order No: AAC 9401906 ProQuest - Dissertation Abstracts

Title: DYNAMIC PILE-SOIL-PILE INTERACTION USING MODEL TESTS UNDER

SIMULATED EARTHQUAKES

Author: SREERAMA, KARUNAKAR

School: UNIVERSITY OF MISSOURI - ROLLA (0135) Degree: PHD

Date: 1993 pp: 205

Advisor: PRAKASH, SHAMSHER

Source: DAI-B 54/08, p. 4300, Feb 1994

Subject: ENGINEERING, CIVIL (0543)

Abstract: Model single piles embedded in cohesive soil were subjected to simulated earthquakes of various base shaking amplitudes and frequencies on the University of Missouri - Rolla shake table. Two and four pile groups at 3D, 5D, and 8D pile spacings were also tested. The single pile and two piles in all the groups were instrumented with strain gages to measure bending moment during simulated earthquakes. The pile cap displacement was measured using a displacement transducer attached to the pile cap. The experimental set up and procedures are discussed in detail. The test results are presented.

The data obtained in the simulated earthquake experiments on single pile and pile groups are then interpreted. The soil-pile stiffness and damping properties are back calculated from the observed displacement response of the single pile and pile groups. These properties are a function of the strain. The dynamic shear modulus is computed from the soil-single pile stiffness. The deflection of the pile along the length is obtained by integrating the bending moments.

A relationship is developed between dynamic shear modulus and dynamic soil-single pile stiffness based on the observed behavior of single pile during earthquakes. Non-dimensional curves are developed for dynamic pile-soil-pile group interaction for stiffness and damping. The dynamic pile-soil-pile group interaction factor is found to depend on the pile spacing and the number of piles in the group and is frequency independent. An expression is developed for predicting the dynamic pile group interaction factors based on the experimental data. The experimental non-dimensional relationships for dynamic pile group interaction factors are compared with several published studies. The total damping ratio in the pile groups is greater than the damping ratio in single piles. The magnitude of this increase is proportional to the number of piles in the group and pile spacing. Material damping in single pile and pile groups is considerably less than the material damping observed in conventional dynamic soil testing.

A procedure has been developed for predicting the response of single pile and pile groups during simulated earthquakes. The prediction procedure holds promise as a design tool for seismic pile analysis and for dynamic soil structure interaction analysis. A numerical example is presented to illustrate the prediction procedure.

Order No: AAC 1353027 ProQuest - Dissertation Abstracts

Title: ESTIMATION OF PILE FRICTIONAL CAPACITY IN CLAYEY

SEDIMENTARY DEPOSITS IN TAIPEI USING CPT DATA

Author: JIE, WIE-KONG

School: SAN JOSE STATE UNIVERSITY (6265) Degree: MS Date: 1993

pp: 135

Source: MAI 31/04, p. 1865, Winter 1993

Subject: ENGINEERING, CIVIL (0543)

Abstract: This thesis demonstrates that the present state-of-the-art methods for utilizing Cone Penetration Test data for pile frictional capacity prediction in cohesive soils agree reasonably well the observed maximum capacity of the tested piles when using methods suggested by Tumay and Fakhroo (1981). However, the method suggested by Schmertmann (1978) tends to underestimate the load carrying ability of the piles.

The observed maximum frictional capacity is defined from the load versus butt settlement curve of pile test results.

The difference between these two computed frictional capacities is due to the significant difference of their relevant adhesion factors for cone friction lower than 0.36 kg/cm$\sp2$, where the adhesion factor from Tumay et.al. is higher than from Schmertmann.

Order No: AAC 9419038 ProQuest - Dissertation Abstracts

Title: OPTIMIZATION OF STEEL PILE FOUNDATIONS WITH RIGID OR

FLEXIBLE CONCRETE SLABS

Author: HOBACK, ALAN SCOTT

School: WASHINGTON UNIVERSITY (0252) Degree: DSC Date: 1993

pp: 155

Advisor: TRUMAN, KEVIN Z.

Source: DAI-B 55/02, p. 516, Aug 1994

Subject: ENGINEERING, CIVIL (0543)\; ENGINEERING, SYSTEM SCIENCE

(0790)

Abstract: An automated design and optimization process for pile foundations with flexible or rigid concrete slabs is presented. The optimization process is applied to lock and dam foundation examples. The goal is to create a computer program that automatically optimizes the design. The designers specify the requirements of the design such as the loading conditions and soil properties. Then the program computes a low cost design. This can save time for the designer and can save on the construction costs. The pile properties and orientations are the only varied properties. Within the scope of this work the foundation dimensions are not variable.

Two methods of pile slab analysis are used. The methods assume that either the concrete slab is thick and rigid (inflexible) or that it is thin and flexible. A finite element program is used to perform the flexible analysis which is a major component of the optimization. The program uses a novel method of pile assembly. The piles are assembled at any point within the slab elements.

Several advances have been made with the optimality criteria formulation and the general optimization procedures. The Percent method is a new method which has been developed to optimize discrete problems. Previously search methods were used. This required all combinations of the discrete options to be searched through to find the global optimum. The Percent method does not search. It is gradient-based which is much more efficient than searching.

Several examples are shown. The first set of examples demonstrate the performance and usefulness of certain new advances. A second set of examples applies the optimization capabilities to practical problems. The examples demonstrate that optimal sizes, alignments and numbers of piles can be determined by an optimization method. The examples have significant construction cost savings.

Order No: AAC 9310534 ProQuest - Dissertation Abstracts

Title: DYNAMIC SOIL RESPONSE DURING PILE AND ROD PENETRATION

(PILE PENETRATION)

Author: SHENG, YUANJING

School: THE UNIVERSITY OF AKRON (0003) Degree: PHD Date: 1992

pp: 175

Advisor: LIANG, ROBERT Y.

Source: DAI-B 53/11, p. 5875, May 1993

Subject: ENGINEERING, CIVIL (0543)\; APPLIED MECHANICS (0346)\;

GEOTECHNOLOGY (0428)

Abstract: The application of stress wave propagation theory to piling problems has become an accepted practice in the geotechnical profession. In the design stage, wave equation computer simulations provide results to help engineers in selecting the most effective pile driving hammer and the most economical pile size. During pile installation, the bearing graph generated by wave equation analysis provides on-site pile driving control criteria. However, the accuracy of wave equation analysis results depends on two important ingredients: the input of representative model parameters and the dynamic pile-soil interaction model used in the computer simulation.

The aim of this research was to provide better handling of the two important ingredients involved in the pile driving analysis. This was accomplished by developing an improved pile-soil interaction model and a novel in-situ testing technique for determination of model parameters.

To simulate pile driving, a driven rod test with attendant measurements of force and velocity near the rod top during each hammer blow was developed. This in-situ test provided high strain testing data (HST data) which could be used to determine the site-specific Smith soil model parameters. The wave equation based computer program CAPWAPC$\sp{\rm TM}$ was used to interpret the HST data. An empirical "extrapolation law" was proposed based on the CAPWAPC$\sp{\rm TM}$ analyses to transfer the deduced Smith model parameters to full scale pile driving conditions. An example was presented to demonstrate the satisfactory application of the developed in-situ testing technique.

For the study of pile-soil interaction, a new HST data interpretation theory was derived. This theory enabled the development of an improved pile-soil interaction model based on the HST data measured during pile driving. The proposed model includes the desirable feature of hyperbolic nonlinear representation of the static soil resistance as well as velocity dependent viscous damping. A case study indicates that the proposed model differs from the Smith type models, particularly in predicting the static load-settlement curve. Also, the dynamic term of the model demonstrates the ability to capture the inertial damping in pile driving problems.

Order No: AAC 9331220 ProQuest - Dissertation Abstracts

Title: NUMERICAL MODELLING OF A LATERALLY LOADED PILE GROUP BY

FINITE ELEMENT METHOD (PILE)

Author: SUBRAMANIAN, SHANMUGARAJ

School: UNIVERSITY OF FLORIDA (0070) Degree: PHD Date: 1992

pp: 248

Advisor: MCVAY, MICHAEL C.

Source: DAI-B 54/06, p. 3242, Dec 1993

Subject: ENGINEERING, CIVIL (0543)\; GEOTECHNOLOGY (0428)

Abstract: The main purpose of this research is to create a nonlinear finite element computer program (LPG) specifically for analyzing a laterally loaded pile group. In the program, piles are modeled by 3-D finite beam elements. Pile-soil and pile-soil-pile interaction among the piles and soil within the group is modeled by soil springs. The interaction is assumed to be effected by two types of springs, near-field and far-field soil springs. The near-field soil springs are nonlinear and their stiffnesses are obtained from p-y curves. The far-field soil springs are linear and their stiffnesses are obtained from Mindlin's flexibility equations. Axial loads are transferred to the soil through the axial linear soil springs attached to the tips of the piles. Input parameters for all the soil springs can be obtained from insitu and/or laboratory tests.

The program gives both linear and nonlinear solutions comparable to the solutions of a commercially available software (COM624) for a laterally loaded single pile. It also gives Poulos's Integral Solution for a laterally loaded linear elastic pile group system.

Finally, the program was used to predict both a single pile and pile group response at a Houston, Texas, site for static and cyclic loadings. Good results were obtained for both cases using the same soil parameters obtained from the site.

Order No: AAC 9301840 ProQuest - Dissertation Abstracts

Title: SEISMIC RESPONSE OF PILE FOUNDATIONS EVALUATED THROUGH CASE HISTORIES

Author: FAN, KE

School: STATE UNIVERSITY OF NEW YORK AT BUFFALO (0656)

Degree: PHD Date: 1992 pp: 328

Advisor: GAZETAS, GEORGE

Source: DAI-B 53/09, p. 4827, Mar 1993

Subject: ENGINEERING, CIVIL (0543)

Abstract: A general methodology is outlined for a complete seismic soil-pile-foundation-structure interaction analysis. Three multi-step procedures are developed within the framework of this general methodology. Procedure I is the simplest engineering procedure, making use of simple formulae and dimensionless charts. Procedure II uses simplified analytical and numerical models (such as the Beam-on-Dynamic-Winkler-Foundation) in the analyses. Procedure III utilizes rigorous formulations in its various steps (such as finite-element, boundary-element, etc.)

Numerical studies are conducted on the dynamic response of single pile and pile groups in several idealized soil profiles with rigorous analytical-numerical formulations and simplified methods. From these studies, dimensionless graphs of complex-valued dynamic interaction factors are developed for all modes of harmonic excitation, and parametric results for the effective seismic input motion of the foundation are presented for a number of typical pile group configurations. The effect of group configuration on the dynamic impedances of pile foundations is investigated and insight is gained into the nature of dynamic pile-soil-pile interaction. The presented results (graphs and simple expressions) may be utilized to determine the seismic response of pile foundations with Procedure I.

Simplified methods of solution (to be used in the framework of Procedure II) are presented to determine kinematic seismic displacements and bending moments, as well as dynamic impedances, of single piles and pile groups. Extensive comparisons of the developed simplified methods with the boundary-integral method and the extended-Tajimi method reveal a good agreement.

Two well-documented case histories, involving the seismic response of a bridge pile foundation and a building pile foundation, are studied to validate and calibrate the presented methods of solution. Records obtained in these two cases include free-field accelerograms at the ground surface and the ground base, accelerograms on the foundation and superstructure, and bending and axial strain histories at several depths along two piles (in each case). Both simplified and sophisticated methods (Procedures II and III) are used in the analyses. Generally, the computed and recorded responses of the soil-pile-foundation-structure system compare reasonably well, but with some exceptions that are discussed in detail. The simplified methods of solution give satisfactory predictions of bending strain distributions along the pile. Further research work is recommended to fully explore the recorded data of these two case histories.

Order No: AAC 9331220 ProQuest - Dissertation Abstracts

Title: NUMERICAL MODELLING OF A LATERALLY LOADED PILE GROUP BY FINITE ELEMENT METHOD (PILE)

Author: SUBRAMANIAN, SHANMUGARAJ

School: UNIVERSITY OF FLORIDA (0070) Degree: PHD Date: 1992

pp: 248

Advisor: MCVAY, MICHAEL C.

Source: DAI-B 54/06, p. 3242, Dec 1993

Subject: ENGINEERING, CIVIL (0543)\; GEOTECHNOLOGY (0428)

Abstract: The main purpose of this research is to create a nonlinear finite element computer program (LPG) specifically for analyzing a laterally loaded pile group. In the program, piles are modeled by 3-D finite beam elements. Pile-soil and pile-soil-pile interaction among the piles and soil within the group is modeled by soil springs. The interaction is assumed to be effected by two types of springs, near-field and far-field soil springs. The near-field soil springs are nonlinear and their stiffnesses are obtained from p-y curves. The far-field soil springs are linear and their stiffnesses are obtained from Mindlin's flexibility equations. Axial loads are transferred to the soil through the axial linear soil springs attached to the tips of the piles. Input parameters for all the soil springs can be obtained from insitu and/or laboratory tests.

The program gives both linear and nonlinear solutions comparable to the solutions of a commercially available software (COM624) for a laterally loaded single pile. It also gives Poulos's Integral Solution for a laterally loaded linear elastic pile group system.

Finally, the program was used to predict both a single pile and pile group response at a Houston, Texas, site for static and cyclic loadings. Good results were obtained for both cases using the same soil parameters obtained from the site.

Order No: AAC 9301840 ProQuest - Dissertation Abstracts

Title: SEISMIC RESPONSE OF PILE FOUNDATIONS EVALUATED THROUGH CASE HISTORIES

Author: FAN, KE

School: STATE UNIVERSITY OF NEW YORK AT BUFFALO (0656)

Degree: PHD Date: 1992 pp: 328

Advisor: GAZETAS, GEORGE

Source: DAI-B 53/09, p. 4827, Mar 1993

Subject: ENGINEERING, CIVIL (0543)

Abstract: A general methodology is outlined for a complete seismic soil-pile-foundation-structure interaction analysis. Three multi-step procedures are developed within the framework of this general methodology. Procedure I is the simplest engineering procedure, making use of simple formulae and dimensionless charts. Procedure II uses simplified analytical and numerical models (such as the Beam-on-Dynamic-Winkler-Foundation) in the analyses. Procedure III utilizes rigorous formulations in its various steps (such as finite-element, boundary-element, etc.)

Numerical studies are conducted on the dynamic response of single pile and pile groups in several idealized soil profiles with rigorous analytical-numerical formulations and simplified methods. From these studies, dimensionless graphs of complex-valued dynamic interaction factors are developed for all modes of harmonic excitation, and parametric results for the effective seismic input motion of the foundation are presented for a number of typical pile group configurations. The effect of group configuration on the dynamic impedances of pile foundations is investigated and insight is gained into the nature of dynamic pile-soil-pile interaction. The presented results (graphs and simple expressions) may be utilized to determine the seismic response of pile foundations with Procedure I.

Simplified methods of solution (to be used in the framework of Procedure II) are presented to determine kinematic seismic displacements and bending moments, as well as dynamic impedances, of single piles and pile groups. Extensive comparisons of the developed simplified methods with the boundary-integral method and the extended-Tajimi method reveal a good agreement.

Two well-documented case histories, involving the seismic response of a bridge pile foundation and a building pile foundation, are studied to validate and calibrate the presented methods of solution. Records obtained in these two cases include free-field accelerograms at the ground surface and the ground base, accelerograms on the foundation and superstructure, and bending and axial strain histories at several depths along two piles (in each

Order No: AAC 9318077 ProQuest - Dissertation Abstracts

Title: DETERMINATION OF SOIL CONSTANTS FROM STANDARD PENETRATION TEST (STRESS WAVE, PILE DRIVING)

Author: ABOU-MATAR, HASAN MOHAMAD

School: UNIVERSITY OF COLORADO AT BOULDER (0051) Degree: PHD

Date: 1992 pp: 147

Advisor: GOBLE, GEORGE G.

Source: DAI-B 54/02, p. 977, Aug 1993

Subject: ENGINEERING, CIVIL (0543)

Abstract: The Standard Penetration Test is the single most widely used subsurface investigation method. Since the test is basically dynamic it would be very useful if it could be used to obtain more rational measures of soil performance than simply blow count. This would require measurements of force and motion at the top of the drill rod during an SPT blow. In the past great difficulty had been experienced with the acceleration (motion) measurements, but with the recent developments in electronic measurements techniques it has become possible to measure force and acceleration without difficulty. The test is performed in an open drill hole and therefore, there is no shaft resistance along the sides of the drill rod. In this case it is possible to calculate the force and motion at the toe. Measurements have been made in a variety of soil types and the sampler response calculated. Smith model Wave Equation constants were determined from the toe force and motion by a minimization routine to minimize the difference between the toe resistance calculated from top measurements and the same variable obtained from the Smith soil representation. In a similar manner, the mechanical properties of the soil can be obtained. This was done by modeling the soil around the sampler using finite element method. The soil properties were then varied until a good agreement between the calculated and measured displacements at the sampler was obtained.

Order No: AAC 9318090 ProQuest - Dissertation Abstracts

Title: DYNAMICS OF A PILE UNDER AXIAL LOADING: ANALYSIS AND EXPERIMENT (CENTRIFUGE, VIBRATION)

Author: GOBERT, ALAIN THIERRY

School: UNIVERSITY OF COLORADO AT BOULDER (0051) Degree: PHD

Date: 1992 pp: 230

Advisor: PAK, RONALD Y. S.

Source: DAI-B 54/02, p. 982, Aug 1993

Subject: ENGINEERING, CIVIL (0543)\; GEOTECHNOLOGY (0428)\; ENGINEERING, MATERIALS SCIENCE (0794)

Abstract: The importance of soil-structure interaction effects in the behavior of structures and foundations which are required to support vibrating machinery and resist seismic loads has been well recognized. The dynamic behavior of a foundation is an essential element in determining the response of a typical soil-foundation-structure system. This dissertation focuses on the fundamental problem of the behavior of a pile foundation subjected to forced vertical vibrations. A systematic study is undertaken (i) to develop a rational framework of analysis for pile-soil interaction in the context of continuum mechanics, (ii) to demonstrate the usefulness of centrifuge testing to investigate the physical problem at hand and (iii) to assess the applicability of analytical solutions in view of an experimental data base.

A new formulation is presented for the analysis of a floating and deformable pile embedded in a semi-infinite homogeneous medium and subjected to a vertical time-harmonic excitation. The formulation accounts for both the axial and radial deformations of the foundation and can provide for the energy dissipation through geometric and material dampings. The influence on the solution of key parameters, such as the relative stiffness of the pile-soil system and the frequency of the excitation, are examined and theoretical frequency response functions are presented. In parallel, an experimental program is conducted to assess the applicability of the theoretical solution to the physical problem. Tests of small-scale piles embedded in homogeneous overconsolidated clays are used to validate the analytical solution. In addition, small-scale pile foundations embedded in dense dry sands are tested in the two centrifuges at the University of Colorado. The importance of key parameters such as the relative density of the embedding soil, the variation of the shear modulus with depth, the pile-soil relative stiffness, the pile-soil inertia ratio and the static load applied on the pile head by the superstructure are investigated.

Order No: AAC 9331220 ProQuest - Dissertation Abstracts

Title: NUMERICAL MODELLING OF A LATERALLY LOADED PILE GROUP BY FINITE ELEMENT METHOD (PILE)

Author: SUBRAMANIAN, SHANMUGARAJ

School: UNIVERSITY OF FLORIDA (0070) Degree: PHD Date: 1992

pp: 248

Advisor: MCVAY, MICHAEL C.

Source: DAI-B 54/06, p. 3242, Dec 1993

Subject: ENGINEERING, CIVIL (0543)\; GEOTECHNOLOGY (0428)

Abstract: The main purpose of this research is to create a nonlinear finite element computer program (LPG) specifically for analyzing a laterally loaded pile group. In the program, piles are modeled by 3-D finite beam elements. Pile-soil and pile-soil-pile interaction among the piles and soil within the group is modeled by soil springs. The interaction is assumed to be effected by two types of springs, near-field and far-field soil springs. The near-field soil springs are nonlinear and their stiffnesses are obtained from p-y curves. The far-field soil springs are linear and their stiffnesses are obtained from Mindlin's flexibility equations. Axial loads are transferred to the soil through the axial linear soil springs attached to the tips of the piles. Input parameters for all the soil springs can be obtained from insitu and/or laboratory tests.

The program gives both linear and nonlinear solutions comparable to the solutions of a commercially available software (COM624) for a laterally loaded single pile. It also gives Poulos's Integral Solution for a laterally loaded linear elastic pile group system.

Finally, the program was used to predict both a single pile and pile group response at a Houston, Texas, site for static and cyclic loadings. Good results were obtained for both cases using the same soil parameters obtained from the site.

Order No: NOT AVAILABLE FROM UMI ProQuest - Dissertation Abstracts

Title: ANALYSIS OF SHALLOW AND DEEP FOUNDATIONS USING

SOIL-STRUCTURE INTERACTION TECHNIQUES

Author: JONES, ANTHONY JAMES

School: UNIVERSITY OF GLAMORGAN (WALES) (UNITED KINGDOM) (1186)

Degree: PHD Date: 1992 pp: 500

Source: DAI-C 55/02, p. 641, Summer 1994

Subject: ENGINEERING, CIVIL (0543)

Abstract: Methods of analysis are presented which enable the performance of both piled and plain raft foundations to be predicted. Throughout the work the substructure is modelled using a beam-column idealization. This allows the superstructure configuration to be readily incorporated into the model enabling the soil-structure interaction of the complete system to be investigated.

The supporting soil is modelled using a discrete spring representation as in the simplified subgrade reaction theory (S.S.R.T.). The idealized model is analysed using a standard structural program. Relationships are developed between spring stiffness values and soil moduli for a range of axially and laterally loaded pile-soil configurations. The results are verified by comparison with more rigorous solutions and the measured performance of single piles.

The work is extended to consider the interaction of axially and laterally loaded pile groups and piled raft foundations. A simplified treatment of interaction is proposed for approximately uniformly loaded piles. For piles which carry substantially different loads due to interaction effects, a more rigorous procedure is presented.

Consistent matrices are presented to idealize the uniform distribution of soil stiffness along both axially and laterally loaded pile elements. Parametric studies demonstrate that very few elements are required to model laterally loaded piles. The S.S.R.T. method indicates that the results are very sensitive to the number of pile elements used.

The limitations of the proposed method for the analysis of plain raft foundations is investigated. It is demonstrated that soil-structure interaction generally cannot be modelled by varying the soil stiffness across the raft. Consequently, a method of analysis is developed which combines the grillage idealization with the Surface Element Method. A program is developed for the analysis which incorporates the superstructure configuration. The proposed method is verified by comparison with results from the measured performance of existing buildings and other rigorous solutions.

Finally, the combined S.S.R.T./stiffness approach is successfully developed to predict the non-linear performance of single piles. This is achieved using established non-linear load-displacement curves. The solution process involves less iterations than traditional non-linear methods. The computed results are correlated with the measured performance and other solutions of both axially and laterally loaded piles.

Order No: NOT AVAILABLE FROM UMI ProQuest - Dissertation Abstracts

Title: THE LOAD TRANSFER OF A SMALL DIAMETER BORED PILE WITH A PRE-COMPRESSED STEEL CORE (ACTIVE PILE) [DER KRAFTFLUSS IM KLEINBOHRPFAHL MIT AUF DRUCK VORGESPANNTEM STAHLKERN (ACTIVPFAHL)]

Author: SCHIPPINGER, KURT

School: TECHNISCHE UNIVERSITAET GRAZ (AUSTRIA) (5800)

Degree: DRTECHN Date: 1992 pp: 180

Source: DAI-C 54/01, p. 313, Spring 1993

Language: GERMAN

Subject: ENGINEERING, CIVIL (0543)

Location: INSTITUTE FOR SOIL MECHANICS AND FOUNDATION ENGINEERING, UNIVERSITY OF TECHNOLOGY, GRAZ, AUSTRIA

Abstract: An overview of small diameter bored pile-systems commonly used in practice is presented and their limits of application briefly discussed. Special emphasis is given to small diameter bored piles suitable for underpinning. Because an exact and unique determination of the bearing capacity of piles is still not possible, various methods according to existing standards of pile design are discussed. Besides the very costly and time consuming in-situ load tests, numerical methods such as the finite element method provide very useful results under certain circumstances. A new pile system, the Active Pile, is presented. The main advantage compared to conventional systems is that underpinning structures will not undergo further settlements. The in-situ test of a scale 1:1, performed in course of a research project on four piles of different length, is described for this new pile (Active Pile). Instrumentation and measurements taken are explained in some detail. The measured data from the in-situ test are presented in tables and diagrams in one pile. The results of the field tests are compared and optimized for the pile length with respect to an economic application. Calibration of the FE-Model is made for one pile and a second one is then analysed using the same material parameters. By varying the soil parameters the load-settlement behaviour of the new pile is simulated for soils, sensitive to settlements.

Order No: AAC 9302963 ProQuest - Dissertation Abstracts

Title: PILE FOUNDATION DESIGN: INTERRELATION OF SAFETY MEASURES FROM DETERMINISTIC AND RELIABILITY-BASED METHODS (DETERMINISTIC METHODS)

Author: ABMALIK, ROSELY BIN

School: MICHIGAN STATE UNIVERSITY (0128) Degree: PHD Date: 1992

pp: 268

Source: DAI-B 53/09, p. 4822, Mar 1993

Subject: ENGINEERING, CIVIL (0543)\; GEOTECHNOLOGY (0428)\;

STATISTICS (0463)

Abstract: An algorithm is developed to interrelate the basic concepts and procedures commonly used in deterministic design of axially-loaded piles in cohesionless soil with reliability-based design methods. The derivation of the algorithm uses the commonly accepted "standard" static formula (Beta-Method) and the in-situ soil exploration data from Standard Penetration Test (SPT).

For the determination of the allowable capacity (${\bf Q}\sb{\rm a}$) in the design of a single pile foundation, safety measures are frequently applied to the predicted capacity (${\bf Q}\sb{\rm p}$). To determine ${\bf Q}\sb{\rm a}$ this study presents the interrelationship between the conventional deterministic safety measure (Factor of Safety, FS) and reliability-based safety measures (Central Factor of Safety, CFS, Reliability Index, $\beta$, and the Probability of Failure, ${\bf P}\sb{\rm f}$) within a systematic and rational framework. Interrelation equations and design charts are derived and calibrated from 23 pile loading tests, 11 of which are on instrumented piles. Consequently, at the recommended FS or $\beta$, the value of ${\bf Q}\sb{\rm a}$ can be determined and interpreted by either deterministic or reliability-based approaches.

Order No: AAC 9301840 ProQuest - Dissertation Abstracts

Title: SEISMIC RESPONSE OF PILE FOUNDATIONS EVALUATED THROUGH CASE HISTORIES

Author: FAN, KE

School: STATE UNIVERSITY OF NEW YORK AT BUFFALO (0656)

Degree: PHD Date: 1992 pp: 328

Advisor: GAZETAS, GEORGE

Source: DAI-B 53/09, p. 4827, Mar 1993

Subject: ENGINEERING, CIVIL (0543)

Abstract: A general methodology is outlined for a complete seismic soil-pile-foundation-structure interaction analysis. Three multi-step procedures are developed within the framework of this general methodology. Procedure I is the simplest engineering procedure, making use of simple formulae and dimensionless charts. Procedure II uses simplified analytical and numerical models (such as the Beam-on-Dynamic-Winkler-Foundation) in the analyses. Procedure III utilizes rigorous formulations in its various steps (such as finite-element, boundary-element, etc.)

Numerical studies are conducted on the dynamic response of single pile and pile groups in several idealized soil profiles with rigorous analytical-numerical formulations and simplified methods. From these studies, dimensionless graphs of complex-valued dynamic interaction factors are developed for all modes of harmonic excitation, and parametric results for the effective seismic input motion of the foundation are presented for a number of typical pile group configurations. The effect of group configuration on the dynamic impedances of pile foundations is investigated and insight is gained into the nature of dynamic pile-soil-pile interaction. The presented results (graphs and simple expressions) may be utilized to determine the seismic response of pile foundations with Procedure I.

Simplified methods of solution (to be used in the framework of Procedure II) are presented to determine kinematic seismic displacements and bending moments, as well as dynamic impedances, of single piles and pile groups. Extensive comparisons of the developed simplified methods with the boundary-integral method and the extended-Tajimi method reveal a good agreement.

Two well-documented case histories, involving the seismic response of a bridge pile foundation and a building pile foundation, are studied to validate and calibrate the presented methods of solution. Records obtained in these two cases include free-field accelerograms at the ground surface and the ground base, accelerograms on the foundation and superstructure, and bending and axial strain histories at several depths along two piles (in each case). Both simplified and sophisticated methods (Procedures II and III) are used in the analyses. Generally, the computed and recorded responses of the soil-pile-foundation-structure system compare reasonably well, but with some exceptions that are discussed in detail. The simplified methods of solution give satisfactory predictions of bending strain distributions along the pile. Further research work is recommended to fully explore the recorded data of these two case histories.

Order No: AAC 9300454 ProQuest - Dissertation Abstracts

Title: NONLINEAR THREE-DIMENSIONAL ANALYSIS OF DOWNDRAG ON PILE GROUPS

Author: JEONG, SANGSEOM

School: TEXAS A&M UNIVERSITY (0803) Degree: PHD Date: 1992

pp: 177

Advisor: BRIAUD, JEAN-LOUIS

Source: DAI-B 53/08, p. 4264, Feb 1993

Subject: ENGINEERING, CIVIL (0543)

Abstract: The downdrag on pile groups was investigated by using a numerical analysis and an analytical study.

The emphasis was on quantifying the reduction of downdrag on piles in a group due to the group effect. The case of a single pile and subsequently the response of groups is analyzed by using a three dimensional non-linear finite element approach. A closed form solution is also developed for the case of the single pile.

It is shown that the downdrag on piles in a group is much less than the downdrag on a single pile. Based on the results obtained, a simple method is proposed to design groups of 9 to 25 piles with spacing-to-diameter ratios varying from 2.5 to 5.0 for downdrag loads.

Order No: AAC 9315346 ProQuest - Dissertation Abstracts

Title: A FEASIBILITY EVALUATION OF UTILIZING HIGH-STRENGTH CONCRETE IN DESIGN AND CONSTRUCTION OF HIGHWAY STRUCTURES

Author: MARTIN, BARNEY T., JR.

School: TULANE UNIVERSITY (0235) Degree: PHD Date: 1992 pp: 246

Advisor: BRUCE, ROBERT N. JR.

Source: DAI-B 54/03, p. 1554, Sep 1993

Subject: ENGINEERING, CIVIL (0543)

Abstract: The objective of this investigation was to evaluate the feasibility of using high-strength concrete in the design and construction of highway bridge structures. A literature search was conducted\; a survey of five regional fabrication plants was performed\; mix designs were studied in the laboratory and in the field\; and three series of tests consisting of a total of nine full-scale specimens were conducted.

The first series included 3 pile specimens tested in flexure. Each of the pile specimens had a 24-in. (610-mm) square cross section with a 12-in. diameter void running its full length. All the pile specimens were 24 ft (7.31 m) long. The pile specimen concrete, at the time of testing, had an average compressive strength of 8,067 psi (55 MPa).

The second series consisted of three full-size bulb-tee specimens. Flexural tests of two bulb-tee specimens are reported. The third specimen is being used for determination of long term behavior.

Three shear tests are also reported. These shear tests were performed using the ends of the two flexural test specimens. Since the shear specimens were taken from the flexural specimens, they had the same cross-sectional configuration and concrete strength as the flexural specimens.

The fabrication and driving of a single 130 ft (39.6 m) pile specimen is reported. The pile specimen had the same cross-sectional configuration as the pile specimens tested in the laboratory. The concrete of the pile specimen had an average 28-day compressive strength of 10,453 psi (72 MPa).

Based on this investigation, the following conclusions are made: (1) High-strength concrete with strengths of 10,000 psi (69 MPa) can be produced using regionally available materials, however, quality control measures presently in use must be upgraded. (2) AASHTO Standard Specifications for Highway Bridges conservatively predicted the behavior of the pile and girder specimens in the area of flexural strength, cracking moment, inclined cracking, shear strength, strand transfer length, effective width of top flange, estimation of prestress losses, modulus of elasticity, and modulus of rupture. (3) Girder camber/deflection measurements were consistent with values calculated using conventional methods. (4) High-strength concrete can be used effectively in long piles. The higher tensile strength and higher precompression is particularly valuable in soft driving conditions where tensile driving stresses are high. (5) Steam curing of high-strength concrete may reduce strength development at later ages. (Abstract shortened by UMI.)

Order No: AAC 9224139 ProQuest - Dissertation Abstracts

Title: UPLIFT RESISTANCE OF PILE SHAFT IN SAND

Author: AL-MHAIDIB, ABDULLAH I.

School: THE UNIVERSITY OF WISCONSIN - MADISON (0262) Degree: PHD

Date: 1992 pp: 246

Advisor: EDIL, TUNCER B.

Source: DAI-B 53/08, p. 4258, Feb 1993

Subject: ENGINEERING, CIVIL (0543)

Abstract: Shaft resistance is a major design factor for piles supporting structures such as transmission towers, harbor structures, and offshore platforms. An experimental program using large-scale instrumented model piles in sand was conducted to study the shaft resistance behavior of piles subject to uplift loads. Model single pipe piles of different diameters (1.75 to 7 inches) and end type (open and closed) were subjected to static uplift loading to failure. The piles which had an embedded length of 6 ft were installed by three different methods (driving, jacking, and a reference undisturbed method with negligible lateral displacement) to assess the influence of method of installation on shaft resistance. The tests were performed in two initial densities of a sand (loose and dense). The experimental results were analyzed statistically. The results show that the initial sand density and the method of pile installation are the most significant factors that affect uplift capacity. Installation methods which cause less disturbance give higher uplift capacity (undisturbed $>$ jacking $>$ driving). Unit shaft resistance could be reduced as much as by half depending on the method of pile installation relative to the undisturbed method. The displacement at the ultimate uplift load is in the range of 0.2 to 0.5 inches and independent of soil type, pile end-type and pile diameter, but depends on method of pile installation.

The distribution of shaft resistance with depth was measured by two different methods. The first method by friction sleeves (direct measurement) and the second method by means of strain gages mounted on model piles. The direct measurement method proves to be time consuming and not very practical. The results indicate that shaft resistance increases linearly with depth (axial load distribution in the pile is parabolic) for the range of length to diameter ratios of 10 to 40 both in loose and dense sand. Significant residual axial loads develop in piles during installation and remain in the pile even after reaching failure in the pullout tests.

The data generated in this study are expected to provide a basis for further theoretical studies in modeling pile-sand frictional interaction.

Order No: AAC 9224178 ProQuest - Dissertation Abstracts

Title: FINITE ELEMENT AND EXPERIMENTAL STUDY OF SOIL-STRUCTURE INTERFACES (PILE)

Author: SENGARA, I. WAYAN

School: THE UNIVERSITY OF WISCONSIN - MADISON (0262) Degree: PHD

Date: 1992 pp: 212

Advisor: BOSSCHER, PETER JAY

Source: DAI-B 53/08, p. 4271, Feb 1993

Subject: ENGINEERING, CIVIL (0543)\; GEOTECHNOLOGY (0428)

Abstract: Many geotechnical engineering problems, such as building-foundation systems, depend on the interaction between soil and structure. Most current stress analyses of such problems neglect the effect of the soil-structure interfaces. For more realistic stress-strain predictions, soil-structure interfaces need to be incorporated into the analysis utilizing advanced elasto-plastic constitutive laws for both soil and interfaces. An integrated nonlinear finite element program that combines elasto-plastic soil and interface elements is developed to realistically model soil-structure interaction problems. A formulation of Plesha's zero thickness interface element is employed to represent the soil-structure interfaces. The elasto-plastic Hierarchical Single Surface (HiSS) constitutive law is adopted to model the soil. Modification of the HiSS model for discontinuities is needed to model the soil-structure interfaces.

Experiments on laboratory surface-sand interfaces and small scale pile tests are performed to verify the performance of the finite element model. A modified direct shear device is developed for the laboratory surface-sand interface tests. This device is used to obtain the soil and interface constitutive parameters used for all finite element modeling. Tests with rough and smooth surfaces under constant stress and constant volume conditions are performed with both the modified direct shear device and the small scale pile test equipment. The performance of the interface model is verified by numerically back predicting the results of these constant stress and constant volume surface-sand interface tests of both devices. These back predictions demonstrate that the adopted interface model is capable of modeling rough and smooth surface-sand interfaces for constant stress and constant volume conditions.

Finite element analysis of modified direct shear and small scale pile tests demonstrates the capabilities of the developed finite element program to model soil-structure interaction problems. The analysis also shows that the interface elements play an important role in realistically modeling the response of the soil-structural system. The use of interface elements, while essential to accurately model smooth surface-sand interfaces, also yields better results when used to model rough surface-sand interfaces compared to analysis without interface elements.

Order No: NOT AVAILABLE FROM UMI ProQuest - Dissertation Abstracts

Title: BEHAVIOUR OF DRIVEN PILES EVALUATED FROM STRESS WAVE MEASUREMENTS PERFORMED DURING DYNAMIC PROBING

Author: ERIKSSON, HAKAN

School: KUNGLIGA TEKNISKA HOGSKOLAN (SWEDEN) (1022)

Degree: TEKNDR Date: 1992 pp: 170

Source: DAI-C 55/01, p. 311, Spring 1994

Subject: GEOTECHNOLOGY (0428)

Publisher: ROYAL INSTITUTE OF TECHNOLOGY, S-100 44 STOCKHOLM 70, SWEDEN

Abstract: The behavior of driven piles in terms of penetration resistance, bearing capacity and load-movement curve in cohesionless soils is studied. The ultimate pile resistance and load-movement curve are evaluated from stress wave measurements performed during dynamic probing by using the Case method and the CAPWAPC program. The penetration resistance of piles is evaluated by wave equation analysis using the ultimate pile resistance and distribution of shaft resistance evaluated from dynamic probing. The accuracy of the different methods to estimate pile behaviour is checked by performing static loading tests on probes and piles.

The unit shaft resistance of the pile is evaluated by enlarging the unit shaft resistance of the probe by using scale factors. The unit toe resistance of the pile is set equal to the unit toe resistance of the probe. The ultimate probe resistance and the scale factors for unit shaft resistance are used to estimate the ultimate pile resistance.

On the basis of two fields tests the following conclusions are drawn: (1) Penetration resistance of piles can be estimated with acceptable accuracy by wave equation analysis. (2) The idea to use the dynamic probe resistance and scale factors to evaluate pile behaviour has been found to be useful. (3) Scale factors of unit shaft resistance shall be evaluated according to the critical depth concept. (4) For small scale factors, the evaluated pile resistance is very sensitive to the estimated percentage of probe shaft resistance. (5) When the ultimate resistance and set-up of piles are estimated directly from dynamic testing on piles, it is important to consider the transferred energy as well as the achieved permanent settlement. (6) When the ultimate probe resistance is evaluated by CAPWAPC analysis it has been found that the ultimate resistance can be overestimated by 45% as an average compared with static loading tests. The Janbu pile driving formula can overestimate the ultimate resistance by 60% as an average.

Order No: AAC NN69989 ProQuest - Dissertation Abstracts

Title: ADFREEZE AND GROUTED PILES IN SALINE PERMAFROST

Author: BIGGAR, KEVIN WILLIAM

School: UNIVERSITY OF ALBERTA (CANADA) (0351) Degree: PHD

Date: 1991 pp: 369

Source: DAI-B 53/08, p. 4259, Feb 1993

Subject: ENGINEERING, CIVIL (0543)

ISBN: 0-315-69989-2

Abstract: Solutes present in the pore water of frozen soils are known to reduce the strength of the soil and increase the time dependent deformation under a constant load. Reduced pile capacities in saline permafrost have caused increased pile foundation costs, and little information is available to engineers to use in design for these conditions. This thesis examines the performance of prebored and backfilled piles in saline frozen soils based upon the results of field and laboratory model pile load tests.

The capacity of piles installed in saline frozen soil is affected by two mechanisms. Firstly the bond between the frozen soil and the pile surface (adfreeze bond) is dramatically weakened by the presence of the solutes. In addition, the saline frozen soil is much more susceptable to time dependent deformation than fresh-water frozen soil. For plain pipe piles installed with a soil-water slurry backfill the reduced adfreeze bond strength governs pile capacities rather than the strength of the saline frozen soil.

To overcome this reduction in adfreeze bond strength and thereby facilitate the mobilization the shear strength of the saline frozen soil surrounding the pile, a number of modifications to the pile surface were tested including sandblasting the pile surface, welding protuberances onto the pile, and the use of a cementitious grout rather than a soil-water slurry as the backfill material.

The use of grouts specially designed to cure in soil at temperatures as cold as $-$10$\sp\circ$C as a backfill material for prebored piles in saline permafrost provided the greatest pile capacities, alleviates any concern regarding solute diffusion through the backfill which will reduce adfreeze bond strengths with time, and are shown to be an economically viable option for pile foundations in saline permafrost.

Order No: AAC NN72695 ProQuest - Dissertation Abstracts

Title: RESPONSE OF PILE FOUNDATIONS TO SIMULATED EARTHQUAKE LOADING: EXPERIMENTAL AND ANALYTICAL RESULTS

Author: GOHL, W. BLAIR

School: THE UNIVERSITY OF BRITISH COLUMBIA (CANADA) (2500)

Degree: PHD Date: 1991 pp: 688

Source: DAI-B 53/12, p. 6438, Jun 1993

Subject: ENGINEERING, CIVIL (0543)

ISBN: 0-315-72695-4

Abstract: To provide a reliable data base suitable for checking various models of dynamic pile foundation response to earthquake shaking, a series of small scale model tests on single piles and pile groups embedded in dry sand foundations were carried out on shaking tables. A similar series of tests were carried out using a geotechnical centrifuge equipped with a base motion actuator. Both the shake table and centrifuge single pile tests were carried out using both sinusoidal and random earthquake input motions over a range of shaking intensities. From the data, details of soil-pile interaction were elucidated. This provided a basis for improvement in methods of estimating required input parameters used in the dynamic analysis of pile foundations.

Prior to each test, shear wave velocity measurements were made throughout the prepared sand foundations using piezoceramic bender elements. The shear wave velocity data were used to compute small strain, elastic shear moduli in the soil. Elastic compression wave velocities were also identified from the bender element responses recorded during the shake table tests.

The single pile tests demonstrated that significant non-linearity and strain softening occurs in near field soil response, which is responsible for reductions in fundamental vibration frequency and pile head stiffness parameters with increasing amplitudes of lateral pile vibration. An analysis technique developed to estimate average effective strains around a single pile leads to predictions of large modulus reduction around the pile, depending on the amplitude of pile vibration.

Soil reaction pressures (p) due to relative horizontal movement between the soil and the pile (y) were deduced from the test data for various cycles of shaking, or so-called p-y curves. The cyclic p-y curves developed show clearly the non-linear, hysteretic near field response near the pile head. Approximately linear elastic p-y response occurs at greater depth. Material damping inferred from the area within the p-y hysteresis loops increases, in general, with increasing pile deflection level.

Comparing the flexural response observed on single piles during the shake table and centrifuge tests, the depth of maximum bending moment relative to the pile diameter has been observed to be greater in the shake table tests. Damping in the low stress level environment of the shake table has been found to be greater than under full scale stress conditions in the centrifuge.

Two-pile tests, where the piles have been oriented inline, offline or at 45 degrees to the direction of shaking, indicate that pile to pile interaction is very strong for inline and 45 degree shaking, and is relatively minor for offline shaking. For close pile separations during inline shaking, elastic theory underpredicts the extent of interaction.

Predictions of single pile response to earthquake shaking have been made using an uncoupled, sub-structure approach incorporating non linear pile head springs and equivalent viscous dashpots (foundation compliances) derived from the test data. (Abstract shortened by UMI.)

Order No: AAC MM79228 ProQuest - Dissertation Abstracts

Title: LOAD-DISPLACEMENT BEHAVIOR OF PILES

Author: ACHARI, GOPAL

School: UNIVERSITY OF CALGARY (CANADA) (0026) Degree: MSC

Date: 1991 pp: 194

Source: MAI 32/01, p. 296, Feb 1994

Subject: ENGINEERING, CIVIL (0543)

ISBN: 0-315-79228-0

Abstract: The effect of loading history was studied by conducting pile load tests in tension after compression and compression after tension. The effect of prior loading was obtained by comparing the tip, shaft and total resistance of the virgin loaded pile to that having a loading history. It was concluded that the ultimate failure load for piles having a loading history was significantly lower than those which had no prior loading. The pile shaft capacity was affected more than the tip capacity as a result of prior loading.

Slow repeated tensile loading on the piles was applied to study the pile displacement behaviour with an increase in the number of repetitions for various load ranges. It was concluded that repeated loads applied upto 10% of the tensile failure load caused negligible movements whereas, for higher load ranges the pile experienced a steady pull-out.

Shaft resistance was found to increase steadily whereas, the tip resistance decreased with an increase in surcharge load. Plots of the average unit shaft resistance with depth show that shaft resistance increases with depth thought at a decreasing rate. (Abstract shortened by UMI.)

Order No: AAC NN76950 ProQuest - Dissertation Abstracts

Title: COMPUTATIONAL MODELLING OF STRUCTURE-FROZEN SOIL/ICE INTERACTION (SOIL/ICE INTERFACE, CREEP)

Author: PUSWEWALA, UDENI G. ANURUDDHA

School: THE UNIVERSITY OF MANITOBA (CANADA) (0303) Degree: PHD

Date: 1991 pp: 273

Source: DAI-B 54/03, p. 1556, Sep 1993

Subject: ENGINEERING, CIVIL (0543)

ISBN: 0-315-76950-5

Abstract: Several computer codes were developed to analyze structure-frozen soil/ice interaction problems in one, two, or three dimensional situations, using three creep models reported in the literature (power law, Fish's unified model, and Domaschuk's model), and to analyze laterally loaded piles in ice/permafrost. An interface element was developed to simulate adfreeze/creep behaviour at soil-structure interfaces. Time/load incremental schemes and iterative algorithms were incorporated in the codes, and provisions were made to conveniently extend the codes to additional creep models. The time incremental codes were based on the constitutive concept of creep in elastic bodies, while the load incremental code involved the concept of incremental elasticity. The reliability and accuracy of all codes were established by comparing predicted results with known analytical solutions.

The codes were used to investigate the capability of the selected creep models to represent the reported behaviour of frozen soils and ice by analyzing different interaction problems such as pressuremeter tests, plate load tests, penetration of rigid bodies, and settlement of footings. The power law model is suitable to simulate cases where primary, attenuating or secondary creep occurs, whereas Fish's model qualitatively reproduces the entire creep curve including the tertiary creep stage. Domaschuk's model qualitatively simulates attenuating creep of frozen sand.

A computationally efficient pile element and the relevant finite element algorithm were developed to model laterally loaded piles in ice/permafrost, by modelling the pile as a beam supported by a spring-dashpot system. A numerical method involving plane strain finite element analyses of laterally loaded rigid cores in frozen media was proposed to derive the appropriate spring and dashpot relationships for the pile element. The deformation behaviour of laterally loaded piles in icy frozen media predicted by this simple pile element was confirmed by rigorous analysis of the identical problems using three dimensional continuum elements. The interface element was used to demonstrate the reported creep behaviour at structure-permafrost interfaces.

The codes can be used as predictive tools to analyze many interaction problems encountered in engineering practice.

Order No: AAC NN69663 ProQuest - Dissertation Abstracts

Title: CONCEPTION DE PIEUX ETABLIS DANS LE PERGELISOL CHARGES LATERALEMENT (FRENCH TEXT)

Author: FORIERO, ADOLFO

School: ECOLE POLYTECHNIQUE, MONTREAL (CANADA) (1105) Degree: PHD

Date: 1991 pp: 818

Source: DAI-B 53/09, p. 4827, Mar 1993

Language: FRENCH

Subject: ENGINEERING, CIVIL (0543)

ISBN: 0-315-69663-X

Abstract: This work deals with the analysis and design of laterally loaded piles in ice-rich frozen soils.

Predicting the behavior of such piles, subjected to prolonged lateral loads, is of importance. A review of classical works, which considered mainly the long term prediction of laterally loaded piles in permafrost based on a secondary creep law, is presented. Other complementary methods are given, also valid for long term prediction, which rely on numerical (finite difference and finite element) as well as analytical (asymptotic solutions based on fractional exponential operators) techniques. We then proceed progressively towards a method, valid not only for long term prediction, but for all times.

A general method of analysis capable of simulating the history of reactions, beginning with the initial elastic state and tending towards a final stationary state is proposed. This method makes use of an elasto-viscoplastic model which simulates the frozen soil-pile interaction at a specific level. A finite element program based on this method is then developed which generates the pile displacements, bending moments, shear loads and frozen soil reactions along the pile as a function of time. Simulations were performed by reducing the yield strength to zero since we are dealing with ice-rich soils susceptible to a pure creep. The program is general in that it provides solutions to those classic elasto-plastic problems, for which the steady state solution of the viscoplastic problem corresponds to the conventional elasto-plastic solution.

Various simulations were performed which incorporated the use of a primary creep law derived from in-situ pressuremeter tests. Results of the computations were compared to large scale tests found in the literature and to small scale tests carried out in a cold room of the Northern Engineering Centre at Ecole Polytechnique.

Finally a method is proposed for the design of laterally loaded piles under combined axial and lateral loads. An expression is developed for the critical axial load which permits the determination of an equivalent length factor used in the interaction formulas recommended by the codes.

Order No: AAC MM75010 ProQuest - Dissertation Abstracts

Title: CASE PILE WAVE EQUATION ANALYSIS: CAPWAPC. EVALUATION OF DRIVEN PILES

Author: EDDE, ROBERT D.

School: UNIVERSITY OF OTTAWA (CANADA) (0918) Degree: MASC

Date: 1991 pp: 185

Advisor: FELLENIUS, BENGT H.

Source: MAI 31/03, p. 1303, Fall 1993

Subject: ENGINEERING, CIVIL (0543)

ISBN: 0-315-75010-3

Abstract: One of the most important aspects of a piled foundation is the bearing capacity of the individual piles. Correct quantitative evaluation of the pile capacity during pile driving requires the use of dynamic monitoring by means of the Pile Driving Analyzer. These monitoring data are combined with a wave equation analysis and processed using a special software called CAPWAP. The CAPWAP analysis is an iterative procedure whereby the calculated force trace is adjusted to agree with the one measured.

The main objective of the thesis study is to produce a statistical indication of the natural variation between the results from a CAPWAP analysis performed on blows within the same soil layer. More specifically, for three selected case histories, the natural variation is studied between contiguous blows of the pile capacity, the resistance distribution between the shaft and the toe, and of the soil dynamic parameters (quakes and damping) as determined in the CAPWAP analysis. (Abstract shortened by UMI.)

Order No: AAC NN69201 ProQuest - Dissertation Abstracts

Title: AN INVESTIGATION OF THE EFFECTS OF THERMAL GRADIENTS ON THE ATTENUATING CREEP BEHAVIOUR OF MODEL PILES IN FROZEN SAND

Author: PRESSNAIL, KIM DOUGLAS

School: UNIVERSITY OF TORONTO (CANADA) (0779) Degree: PHD

Date: 1991 pp: 592

Source: DAI-B 53/08, p. 4268, Feb 1993

Subject: ENGINEERING, CIVIL (0543)

ISBN: 0-315-69201-4

Abstract: There is a concern that when heated basements are thermally insulated, they will experience frost-heave problems due to adfreezing. The writer's earlier work provided an explanation for the apparent lack of adfreezing problems. It was reasoned that heat flowing away from a basement wall and the resulting moisture movement sufficiently reduced the adfreezing bond strength to prevent the transfer of damaging displacements. In this study, model piles embedded in a frozen sand are used to investigate this hypothesis. Recognizing that frost-heave is a time-dependent process, this study begins by examining the attenuating creep behaviour of the model piles when sample conditions are isothermal. Analysis of isothermal test results using the power-law model reveals that sample behaviour varies. To avoid problems inherent with sample variability, methods of step-load testing are refined and the application of the power-law model to step-load test results is developed. Using these developments, and the isothermal test results as a reference, this study proceeds to examine the influence of thermal gradients on the creep behaviour of the model piles. Changes in the resistance of the frozen sand to time-dependent displacements are shown to be directly related to the magnitude and direction of the thermal gradients in the soil surrounding the model piles. The loss of resistance, which occurs when heat flows away from the pile, is shown to be related to the movement of moisture in the frozen soil. Such findings offer support for the validity of the original hypothesis. While the investigations presented here represent an initial step toward verifying this hypothesis, it is hoped that future investigators will carry on the research efforts, and that they will be guided by the methods used here.

Order No: AAC MM72813 ProQuest - Dissertation Abstracts

Title: A STUDY OF THE DEVELOPMENT OF CONSTRUCTION VIBRATION CRITERIA AND THE POTENTIALLY DAMAGING EFFECTS OF PILE-DRIVING VIBRATION ON HISTORICAL AND MODERN BUILDINGS

Author: TYLER, CHRISTINE

School: UNIVERSITY OF WINDSOR (CANADA) (0115) Degree: MASC

Date: 1991 pp: 89

Advisor: GASPAR, R. G.

Source: MAI 31/03, p. 1359, Fall 1993

Subject: ENGINEERING, MECHANICAL (0548)\; ENGINEERING, CIVIL (0543)

ISBN: 0-315-72813-2

Abstract: Vibration measurements were recorded at three sites using a Bruel & Kjaer Frequency Analyzer. Some vibration signals were also tape recorded for Fast Fourier Transform (FFT) analysis. Diesel pile-driving vibrations, which reached a maximum of 0.036 mm/s Peak Particle Velocity at a distance of 15 metres from the Cleary Auditorium, and 0.176 mm/s at a distance of 25 metres from the Baby House, were not considered large enough to cause damage to either building. However, vibratory compacting recorded at the Bellewood Estates subdivision reached a maximum Linear RMS Velocity of 14.1 mm/s at a distance of 44 metres, and was considered to be of sufficient amplitude to cause possible damage to several nearby houses.

The natural frequencies and damping of the Baby House were also determined through FFT analysis of the tape recorded vibration signal.

Spectral Response analysis was found to predict vibration values of about the same magnitude as the other vibration prediction techniques explored in this thesis. However, each technique was found to be quite conservative, and over-predicted the vibration response by several orders of magnitude. Nevertheless, the Spectral Response method did have the advantage of being able to predict the frequencies of highest and lowest amplitude response. (Abstract shortened by UMI.)

Order No: AAC NN69724 ProQuest - Dissertation Abstracts

Title: HYDRAULIC GRADIENT SIMILITUDE METHOD FOR GEOTECHNICAL MODELLING TESTS WITH EMPHASIS ON LATERALLY LOADED PILES

Author: YAN, LI

School: THE UNIVERSITY OF BRITISH COLUMBIA (CANADA) (2500)

Degree: PHD Date: 1990 pp: 356

Source: DAI-B 53/09, p. 4837, Mar 1993

Subject: ENGINEERING, CIVIL (0543)

ISBN: 0-315-69724-5

Abstract: A study has been undertaken to evaluate and apply the hydraulic gradient similitude method to geotechnical model testings. This method employs a high hydraulic gradient across granular soils to effectively increase self-weight stresses in the model.

In the footing tests, it is found that the scaling laws implied in the hydraulic gradient modelling test are satisfied, and are similar to those of the centrifuge modelling technique. Load-settlement curves are found to be similar to those in centrifuge tests. Terzaghi's bearing capacity formula is compared with the observed bearing capacities under different stress levels. The bearing capacity coefficient, $N\sb\gamma$, decreases linearly with footing width on the log-log scale.

In the downhole and crosshole seismic tests, results are used to evaluate the empirical equations that relate shear wave velocity and soil stresses in terms of field stress condition. Only the equation which is based on the significant stresses in the wave propagation and particle motion directions can predict the variation of velocity ratio between the downhole and SH crosshole tests. The stress ratio has some effects on the downhole (or SV crosshole) tests, but not on the SH crosshole tests.

In the laterally loaded pile tests, the pile response to static and cyclic loadings at various stress levels controlled by the hydraulic gradients is examined in terms of pile head response, pile bending moment and soil-pile interaction P-y curves. For the static loading, pile head response and bending moment are found to be significantly affected by the soil-pile relative stiffness, pile diameter, loading condition and pile head fixity. However, little effects of loading eccentricity and pile head fixity are found on the P-y curves. While pile diameter is found to have effects on the P-y curves at large pile deflection, its effects are negligible at small deflection range. The effects of relative soil-pile stiffness on the P-y curves due to stress levels can be normalized by the soil modulus and pile diameter for the curves below 1 pile diameter. For cyclic loading, different pile responses are observed in "one-way" as compared to "two-way" cyclic loading. (Abstract shortened by UMI.)

Order No: AAC 9235954 ProQuest - Dissertation Abstracts

Title: RESPONSE OF TENSION PILES TO SIMULATED SEISMIC MOTION IN SATURATED FINE SAND (SEISMIC MOTION, TENSION LOAD MAGNITUDES)

Author: OCHOA, MAURICIO

School: UNIVERSITY OF HOUSTON (0087) Degree: PHD Date: 1990

pp: 306

Source: DAI-B 53/08, p. 4267, Feb 1993

Subject: ENGINEERING, CIVIL (0543)

Abstract: A laboratory experimental study of tension piles subjected to simulated seismic loading through the soil was conducted. The objective of the study was to assess the magnitude of biased tension load that can be sustained by displacement-type piles driven into loose to medium dense saturated sand. The prototype characteristics modeled in this study consisted of a closed-ended, or plugged, impact-driven pipe pile, 15 to 30 in. in diameter, 20 to 40 ft in length (or top 20 to 40 ft of a longer pile). An acceleration record for particular Magnitude 5.8 seismic event, the Oceanside earthquake of 1986, measured at an offshore (California) deep soil site, 74 km from the epicenter, was selected for detailed study and scaled to higher magnitudes (e.g., Magnitudes of 7.0, 7.5 and 8.0) to simulate more severe earthquake loading conditions on the pile.

A 21 in. high by 20 in. diameter pressure chamber was used to contain the saturated soil and to simulate isotropic effective stresses and drainage conditions. The model test pile, was an instrumented steel closed-ended cylinder, 1 in. in diameter and 16 in. long. Pile-head movement, load vs. depth and pore water pressures in the soil were measured throughout the experiments. The simulated seismic records were applied through the base of the chamber, while the biased tension load was applied simultaneously and continuously through a one-degree-of-freedom weight and spring system to model a simple superstructure. Both the simulated seismic record and/or soil permeability were scaled to model the effect of drainage distance and its effect on pore water pressure generation and dissipation.

Contour plots of stability, mobility and failure conditions for the model pile were developed. The effect of distance between the pile and event epicenter on stability was also considered. For the scaled earthquake studied, the ultimate shaft resistance between pile and soil to applied uplift loads was not affected by the action of the vertical component of the simulated seismic event. For the horizontal component of event magnitudes of 7.0 and 7.5, 74 km from the epicenter, stability was preserved for biased loads of 70% of the static capacity, whereas, for an event of Magnitude 8.0, the condition of stability was reduced to a biased loads of no more than 55% of the static capacity. For piles that did not fail during the simulated seismic event, losses in static capacity of 0-15% occurred.

Order No: AAC 8619777 ProQuest - Dissertation Abstracts

Title: IMAGING STEEP-DIP REFLECTIONS BY THE LINEARLY TRANSFORMED WAVE EQUATION METHOD (LITWEQ)

Author: LI, ZHIMING

School: STANFORD UNIVERSITY (0212) Degree: PHD Date: 1986

pp: 103

Source: DAI-B 47/06, p. 2352, Dec 1986

Subject: GEOPHYSICS (0373)

Abstract: The migration, or imaging, of steep-dip reflections in variable-velocity media has been an important problem in seismic exploration for many years. Claerbout suggested a two-pass phase shift method to image both the topsides and undersides of steep-dip reflectors. Synthetic data calculations confirmed that Claerbout's method improves resolution in imaging steeply dipping reflectors in media where velocities vary vertically. Solving the problem of imaging both the topsides and undersides of steeply dipping reflectors in laterally inhomogeneous media led me to a new wavefield extrapolation method which I call the linearly transformed wave equation (LITWEQ) method.

The LITWEQ method involves transforming a two-dimensional wave equation over both the time and depth axes, analogously to the characteristic method used for solving a one-dimensional wave equation. Applications of LITWEQ migration show that it is more accurate in imaging steep-dip reflections than conventional finite-difference methods of both one-way wave equation migration (such as 15-degree wave equation migration) and two-way wave-equation migration (such as second-order reverse time migration). Since it can handle lateral inhomogeneity, the LITWEQ method also has advantages over Fourier-domain wide-angle methods, such as phase shift and Stolt, when applied to wavefield extrapolations in media where velocities vary laterally.

In strong laterally inhomogeneous media, conventional stacking techniques fail to stack both flat-bed and dipping-bed reflections correctly into common-midpoint (CMP) stacked sections. Even in laterally homogeneous media, normal-moveout (NMO) and CMP stacking techniques still suppress dipping reflections. In order to preserve and image steep-dip reflections, prestack migrations must be applied. Because of its accuracy in imaging steep-dip reflections and its flexibility in handling lateral inhomogeneity, LITWEQ prestack migration gives satisfactory results when applied to both synthetic and field data.

Order No: AAC 8705690 ProQuest - Dissertation Abstracts

Title: NUMERICAL MODELING OF TWO-DIMENSIONAL OVERLAND FLOW

Author: TISDALE, TODD STREET

School: UNIVERSITY OF VIRGINIA (0246) Degree: PHD Date: 1986

pp: 303

Source: DAI-B 48/01, p. 78, Jul 1987

Subject: HYDROLOGY (0388)

Abstract: This study compares the performance of four hydraulic watershed routing techniques used to model the overland flow component of catchment runoff. The first two techniques solve the shallow water equations and kinematic wave equation for flow in one-dimensional, rectangular curvilinear channels. Sets of channels are used to approximate the catchment surface, and channels can run parallel to one another and combine to form a single channel downslope of multiple channels. The last two techniques solve the two-dimensional shallow water equations and kinematic wave equation.

Because these equations have no general analytic solution, they must be solved numerically. To obtain an accurate solution for each equation, more than one numerical method is used to solve it. The two-dimensional equations are solved using finite element methods, and the one-dimensional equations are solved using both finite difference and finite element methods.

Each numerical solution of a runoff equation is tested to determine its suitability for modeling overland flow. Tests are conducted to determine (1) ability to maintain continuity, (2) computational accuracy, (3) computational speed, and (4) under what overland flow conditions the kinematic wave equation can be used in place of the shallow water equations. Test results reveal that (1) all solutions maintain continuity\; (2) solutions of the one-dimensional kinematic wave equation exhibit the best computational accuracy\; (3) solutions of the one-dimensional kinematic wave equation are computationally faster than the other techniques\; and (4) the one-dimensional kinematic wave equation can be used in place of one-dimensional shallow water equations for kinematic wave numbers of ten or greater, while the two-dimensional kinematic wave equation requires a kinematic wave number of fifty or greater before it can be used.

The best overall performance is given by a solution of the one-dimensional kinematic wave equation. This hydraulic watershed routing technique is applied to a prototype catchment, and simulated catchment discharges exhibit good agreement with measured discharges. In contrast, a finite element solution of the two-dimensional kinematic wave equation is applied to the same catchment, and it generates discharges that grossly underestimate measured values.

Finally, to demonstrate a potential use of the solution for the one-dimensional kinematic wave equation, it is incorporated into a nonpoint source pollution model, and this model is applied to the prototype catchment.

Order No: AAC 8614147 ProQuest - Dissertation Abstracts

Title: PARABOLIC APPROXIMATIONS OF THE REDUCED WAVE EQUATION

Author: PANCHANG, VIJAY G.

School: UNIVERSITY OF MAINE (0113) Degree: PHD Date: 1985

pp: 147

Source: DAI-B 47/06, p. 2545, Dec 1986

Subject: ENGINEERING, CIVIL (0543)

Abstract: A numerical technique is developed for modelling the evolution of wave spectra in bays. The technique presented is based on a modified form of the reduced wave equation, thus incorporating refraction and diffraction of waves. The parabolic approximation is shown to be superior to the classical Born and Rytov approximations, and can be solved conveniently. It has been demonstrated in the literature that energy dissipation can be built into the transformed parabolic equation. The principle is extended to investigate spectral evolution, by including a source function to describe atmospheric input and nonlinear energy transfer. A set of spectral components is used, and a solution process appropriate for the proposed technique is developed. Comparison to laboratory and prototype data are presented.

The parabolic approximations used in the model are frequently used when the reduced wave equation is encountered. Two such approximations have been derived by Corones in 1975, where "splitting matrices" are resorted to. The reasons for the apriori selection of these splitting matrices are not well-explained in the literature, however. It is explained that the parabolic approximation commonly used in coastal engineering (also derived by Radder in 1979) corresponds to the first-order WKB approximation when the one-dimensional form of the equation is considered. It is also shown that the splitting matrices corresponding to the two approximations derived by Corones (and used by Candel in 1979 for application to aeroacoustics and by Radder and others in coastal engineering) can be derived from the generalized WKB theory. Other splitting matrices, which correspond to the second-order WKB approximation and another class of improved WKB approximations, are obtained, and used in Corones' method to derive other parabolic approximations. As demonstrated by example, the new approximations improve the results of existing parabolic model.

Corones has also indicated a method for correcting the parabolic approximations. This method is applied to the second-order approximation to derive the correction series, described in the literature on physical grounds. A comparison is made for of the first and second order correction models. Though the second order approximation is better, the corrections to the first order approximation are less sensitive to rapid variations in the K that may be realistically expected. It is also seen that for a non-dimensional function (delta) = f(K) < about 0.0015, the solution of the first order parabolic approximation shows no deviation from the solution of the reduced wave equation. (Abstract shortened with permission of author.)

Order No: NOT AVAILABLE FROM UMI ProQuest - Dissertation Abstracts

Title: DISPERSION ANALYSES OF FINITE ELEMENT SOLUTIONS OF THE SHALLOW WATER EQUATIONS

Author: FOREMAN, MICHAEL GEORGE GARVIN

School: THE UNIVERSITY OF BRITISH COLUMBIA (CANADA) (2500)

Degree: PHD Date: 1984

Source: DAI-B 46/12, p. 4272, Jun 1986

Subject: MATHEMATICS (0405)

Abstract: This thesis investigates the accuracy and stability of finite element solutions of the shallow water equations. The method of investigation is referred to as a dispersion analysis. It compares numerical phase velocities, group velocities, and wave amplification factors to their analytic counterparts.

Chapter 1 discusses the shallow water equations, finite element and finite difference methods, and reviews previous work. The advantages and disadvantages of a dispersion analysis are also discussed.

Chapters 2 and 3 are restricted to numerical solutions of the one dimensional linearized shallow water equations. The phase and group velocities of eight spatial discretizations are calculated and examined for their relative merits. The most accurate two-step time-stepping methods are found for three finite element spatial discretizations\; the wave equation model of Gray and Lynch, the Galerkin method with linear basis functions, and the Galerkin method which combines quadratic basis functions for velocity with linear functions for elevation. It is also shown that with an appropriate time-stepping method, lumping the wave equation model need not cause an accuracy loss.

Chapter 4 extends the analysis to the linearized two dimensional equations. Finite element solutions are computed for two configurations of triangular elements. Two finite element methods, Thacker's method and the lumped wave equation model, are shown to be cost competitive and as accurate as the Richardson-Sielecki explicit finite difference method. The analysis also suggests that finite element meshes comprised of equilateral triangles most accurately represent phase and group velocity.

Chapter 5 extends the one dimensional dispersion analysis to include boundary conditions. The stability and relative accuracy of several absorbing boundary conditions are examined. Accuracy is evaluated through the calculation of reflection coefficients. An unstable boundary condition of the type examined by Trefethen is also found.

Order No: AAC 8401616 ProQuest - Dissertation Abstracts

Title: DETERMINATION OF THE ACOUSTICAL IMPEDANCE OF A LAYERED MEDIUM BY THE GOPINATH-SONDHI INTEGRAL EQUATION

Author: SARWAR, A. K. M.

School: INDIANA UNIVERSITY (0093) Degree: PHD Date: 1983

pp: 219

Source: DAI-B 44/10, p. 3021, Apr 1984

Subject: GEOPHYSICS (0373)

Abstract: This thesis concerns the application of the Gopinath and Sondhi (GS) inversion method in the reconstructions of the impedance travel-time profiles. The equation of motion and the stress-strain relationship governing the propagation of one-dimensional dilatational waves in a horizontally layered medium have been transformed to two coupled first order equations whose inverse solution is obtained through application of the GS integral equation.

A scattering solution of the Schrodinger wave equation for an explosive point source leads us to express the kernel of the GS integral equation in terms of a seismic reflection response. A convolution equation is developed which, in special case, relates the kernels of the GS and the Faddeev-Marchenko equations and thereby yields insight into the different integral methods of inverse scattering.

The primary approach includes both analytical and numerical solutions. The seismic reflection response is synthesized following the method of Howard (1981). The modified impulse response, which is the kernel of the GS integral equation, is then generated from the reflection response. The GS integral equation is approximated by the trapezoidal rule and the resulting matrix equation is solved by the Gaussian elimination method.

The sufficiency condition for the existence and uniqueness of the solution to the GS integral equation requires that the impedance be piecewise differentiable. This constraint is weaker than the twice differentiability constraint of the Schrodinger wave equation methods. Inversion has been tested on modified impulse response data generated from continuous impedance profiles whose derivatives have step-like discontinuities. The reconstructions are satisfactory. The GS inversion method has also been tested on the modified impulse response data perturbed by white noise and found to be reasonably stable under noise perturbations.

The GS inversion method is also tested in the presence of high and low frequency roll off. It produces remarkably satisfactory reconstruction from a modified impulse response data that has been noise corrupted (signal to noise ratio 2:1) as well as band-limited in the high frequencies with a cutoff frequency equal to .1f(,NYQUIST). In contrast to this, it is not possible to determine the magnitude of an impedance profile by the GS inversion method when the low frequencies are missing from the seismic data.

Order No: AAC 8220510 ProQuest - Dissertation Abstracts

Title: PREDICTIVE TECHNIQUES FOR MARINE MULTIPLE SUPPRESSION

Author: MORLEY, LAURENCE CHARLES

School: STANFORD UNIVERSITY (0212) Degree: PHD Date: 1982

pp: 73

Source: DAI-B 43/04, p. 1016, Oct 1982

Subject: GEOPHYSICS (0373)

Abstract: Standard predictive multiple suppression techniques in marine reflection seismology usually resort to one-dimensional assumptions about the underlying earth model. This thesis develops a number of predictive suppression methods based on a multiple model which relaxes these requirements of zero offset and zero dip, yet assumes vertical incidence propagation in the water layer. This culminates in a method called "seafloor-consistent multiple suppression"--a name chosen by analogy to the "surface-consistent statics" problem of reflection seismology.

The seafloor-consistent method models each seismic trace as a convolution of an average frequency response with anomalous shot, geophone, midpoint and offset responses. In the log-frequency domain, this becomes a separable, additive model which can be solved by linear least-squares techniques. The anomalous responses are solved for each frequency in "shot-receiver" space with frequency as the outer loop of the algorithm. Since one can argue on physical grounds that the reverberation response for any particular trace must be minimum phase, it suffices to solve only for amplitude responses and ignore phase contributions.

The method is applied to a marine seismic line from the Flemish Cap area of the Labrador Sea with extremely encouraging results.

The second part of this thesis uses the concept of a replacement medium--specifically, a replacement impedance medium, to develop a theory of multiple suppression valid for all angles of offset and dip. A generalized wave equation dereverberation operator is derived which includes the effects of wave propagation, seafloor reflectivity, and shot and receiver ghost responses. Most current methods of predictive multiple suppression are shown to be approximations to this general operator.

Order No: AAC NN89399 ProQuest - Dissertation Abstracts

Title: SHEAR DESIGN OF PILE CAPS AND OTHER MEMBERS WITHOUT TRANSVERSE REINFORCEMENT

Author: ZHOU, ZONGYU

School: THE UNIVERSITY OF BRITISH COLUMBIA (CANADA) (2500)

Degree: PHD Date: 1994 pp: 282

Advisor: ADEBAB, P.

Source: DAI-B 55/08, p. 3472, Feb 1995

Subject: ENGINEERING, CIVIL (0543)

ISBN: 0-315-89399-0

Abstract: This thesis deals with the shear design of structural concrete members without transverse reinforcement. The three major parts of this study are the transverse splitting of compression struts confined by plain concrete, the development of a rational design procedure for deep pile caps, as well as a general study of the shear transfer mechanisms of concrete beams.

Three-dimensional compression struts that are unreinforced and confined by plain concrete, as occur in deep pile caps, were studied both analytically and experimentally. Based on the study results, bearing stress limits are proposed to prevent compression struts from transverse splitting. The maximum bearing stress depends on the amount of confinement, as well as the aspect ratio (height to width) of the compression strut.

The proposed bearing stress limit was incorporated into a strut-and-tie model to develop a rational design procedure for deep pile caps. Two methods are proposed. The first method is a direct extension of two-dimensional strut-and-tie models used for deep beams. The second method is presented in a more traditional form in which "flexural design" and "shear design" are separated. The shear design is accomplished by limiting the bearing stress at the columns and the piles. The first method is more appropriate for analysis, while the second method is more appropriate for design. The rationality and accuracy of the proposed methods are demonstrated by the comparison with previous test results.

In the final part of this study, the influence of bond between concrete and longitudinal reinforcement upon the load transfer mechanism of both deep members and slender members without stirrups are investigated. An interpretation of an important shear failure mechanism is presented.

Order No: AAC 9421549 ProQuest - Dissertation Abstracts

Title: DYNAMIC RESPONSE OF OFFSHORE STEEL-JACKET PLATFORMS SUBJECT TO MEASURED SEAFLOOR SEISMIC GROUND MOTIONS (SANTA BARBARA CHANNEL)

Author: SMITH, CHARLES EDWARD

School: THE GEORGE WASHINGTON UNIVERSITY (0075) Degree: DSC

Date: 1994 pp: 349

Advisor: SARKANI, SHAHRAM

Source: DAI-B 55/03, p. 1069, Sep 1994

Subject: ENGINEERING, CIVIL (0543)\; ENGINEERING, MARINE (0547)\;

GEOTECHNOLOGY (0428)

Abstract: The seismic analysis of an offshore platform may be accomplished using classical finite element techniques, modified to take into account the fluid-structure and the soil-pile interaction effects. However, a major uncertainty exists as to what constitutes an appropriate seismic forcing function. Current practice employs seismic data recorded from onshore sites. Recent research, on the other hand, suggests that the seafloor does not respond in the same manner as onshore sites during an earthquake. The presence of the water column above the seafloor, soft-saturated seafloor sediments, and the dissimilarity between the impedance at the soil-water interface can interact to cause marked differences in the resulting ground motions. In this dissertation, a series of free-field strong ground-motion records obtained from actual seafloor sites, located offshore southern California in the Santa Barbara Channel, are analyzed and compared to onshore earthquake records to further identify and substantiate the dissimilarity between the two conditions. In addition, an offshore steel-jacket structure, typical of the type employed by the oil and gas industry, is analyzed using compatible earthquake time-series from both onshore and offshore sites to investigate differences in platform response. As a result of this investigation, recommendations are put forth for the type of seismic forcing functions to be used in the design of new or in the requalification of existing offshore structures, as well as for future research required to further advance the state-of-the-practice.

Order No: AAC 1357845 ProQuest - Dissertation Abstracts

Title: DYNAMIC ANALYSIS OF PLUGGED PIPE PILES IN CLAY

Author: CHERNAUSKAS, LES ROBERT

School: UNIVERSITY OF LOWELL (0111) Degree: MS Date: 1994

pp: 272

Advisor: PAIKOWSKY, SAMUEL G.

Source: MAI 33/01, p. 226, Feb 1995

Subject: ENGINEERING, CIVIL (0543)\; GEOTECHNOLOGY (0428)

Abstract: An open ended pipe pile can become plugged when sufficient frictional resistance is developed by the inner soil cylinder within the pile (soil plug), thereby preventing further intrusion of the soil into the pile. When plugging occurs in an impact driven pipe pile, a complex interaction between the pile and soil plug takes place, causing the propagating stress wave to undergo an abrupt change. Current dynamic analyses of piles are based on the one-dimensional wave equation (e.g. CAPWAP, TEPWAP). Although the wave equation has the capability to indirectly accommodate the inner soil cylinder, it does not accurately simulate the physical phenomena when the pile is plugged, causing the predicted capacity of plugged piles to differ from actual field observations.

A new approach was investigated in which the spatial stress transformation within the soil plug was modeled using an axi-symmetric wave propagation formulation. A two-dimensional finite difference solution was developed for that formulation. This numerical solution was implemented in a computer program called PWAP (Plug Wave Analysis Program). A case study was then used to examine the applicability of the solution and to determine if the static capacity of the pile could be predicted more accurately. The PWAP analysis was performed on a pipe pile driven in Empire clay using dynamic records taken from a well documented case study. The results of PWAP were compared to the results of TEPWAP and CAPWAP, which do not simulate the effects of soil plugging. The PWAP analysis resulted in a better force match than the conventional analyses and predicted the pile capacity to 87% of the load test value, compared to about 30% for the conventional method predictions.

Order No: AAC 9434511 ProQuest - Dissertation Abstracts

Title: BEHAVIOR OF DISPLACEMENT PILES IN AN OVERCONSOLIDATED CLAY

Author: MILLER, GERALD ANDREW

School: UNIVERSITY OF MASSACHUSETTS (0118) Degree: PHD

Date: 1994 pp: 428

Advisor: LUTENEGGER, ALAN J.

Source: DAI-B 55/08, p. 3464, Feb 1995

Subject: ENGINEERING, CIVIL (0543)

Abstract: At the National Geotechnical Experimentation Site (NGES) on the University of Massachusetts Amherst Campus, 44 pipe piles with diameters in the range of 60 to 168 mm and lengths of 1.5 to 10.7 m, were installed and load tested. The majority of piles were installed in a moderately plastic, varved clay crust with overconsolidation ratios in the range of 4 to 9. Open-ended and closed-ended (60$\sp\circ$ apex cone) piles were installed by driving and jacking. An extensive program of laboratory and in situ soil testing was also completed.

Axial compressive load tests to failure were conducted at a predetermined time after installation and some piles were subjected to repeat load tests. Additionally, load tests were conducted on pile cone tips, independent of the pile shaft. Average unit skin friction was backcalculated from the interpreted pile failure load and estimated values of end-bearing.

The investigation revealed that: (1) pile driving resulted in more intrusion of soil into the pile (less plugging), as compared to pile jacking\; (2) plugging was a function of pile diameter and soil characteristics\; (3) jacking resulted in higher skin friction capacity than driving\; (4) skin friction capacity of piles depended on the degree of plugging\; (5) pile skin friction capacity appeared to be a function of the lateral reconsolidation effective stress\; (6) the operative lateral effective stress acting on the piles at failure appeared to vary over wide limits between values close to the at rest earth pressure (K$\sb{\rm o}$) and the reconsolidation lateral earth pressure K$\sb{\rm o}$), estimated from in situ test results\; (7) the operative coefficient of friction at the soil-pile interface at failure was best estimated from the results of interface direct shear tests using remolded soil\; and (8) repeat load tests on piles resulted in successively higher failure loads until the third load test, after which the capacity dropped slightly. The mechanism responsible appeared to be an increase in end-bearing.

A new effective stress analysis for pile skin friction was proposed. The analysis allows for consideration of the installation method, degree of plugging during open-ended penetration and the estimated lateral stress conditions around displacement piles installed in overconsolidated clay.

Order No: AAC 9322566 ProQuest - Dissertation Abstracts

Title: MODELING OF SAND-STRUCTURE INTERFACES (GRAIN CRUSHING)

Author: ZEGHAL, MORCHED

School: THE UNIVERSITY OF WISCONSIN - MADISON (0262) Degree: PHD

Date: 1993 pp: 194

Advisor: EDIL, TUNCER B.

Source: DAI-B 54/08, p. 4302, Feb 1994

Subject: ENGINEERING, CIVIL (0543)

Abstract: The sand-structure interface, developed under monotonic loading, is modeled based on physical observations. A constitutive model of the rock joint problem has been adopted to the sand-structure interface. This model takes into account the macroscopic conditions to yield a general constitutive law applicable to a wide range of contact problems, such as rock discontinuities and sand-structure interaction problems. The micro-structural considerations constitute the specialization of the general equations to a specific problem. The shear band at the sand-structure interface is idealized to be sinusoidal in shape and the friction coefficient is taken to be a function of the plastic work. The work dissipated plastically during shear is taken as an index of grain crushing. This elasto-plastic model, with non-hardening features incorporated in it, predicted the shear stresses rather well for the two extreme loading paths i.e., constant stress and constant volume test conditions in a modified direct shear interface test. At this point, the model is not capable of modeling any volumetric compression during shear\; however, the prediction of dilation is satisfactory for the tests run with low initial confining pressures. The model is also capable of simulating the small-scale pile shaft-sand pullout tests. The shaft resistance is accurately reproduced.

The microstructural features of the model were drawn from an intensive numerical simulation using the discrete element method. The parametric study showed that neither the ball and wall stiffnesses nor the ball and wall friction had any significant qualitative effects on the results. The damping and degree of roughness (used to simulate the structure in the interface) showed a significant effect. The discrete element modeling of sand grains at smooth and rough interfaces revealed the shape of the resulting shear bands and formed the basis for the constitutive model development.

Additionally, Desai's constitutive model for soil mass is rederived and implemented into the finite element code named PLASOIL. The parameters of this model are easy to obtain and were determined for Portage sand. The backpredicted experimental tests suggest that the soil model is behaving in a reasonable manner.

The interface study constitutes a preliminary step toward a more comprehensive and complete model. The whole package is a contribution in the form of presenting the different elements necessary to boundary value problems involving sand-structure interaction, i.e. the structure, the interface and the sand.

Order No: AAC 8117697 ProQuest - Dissertation Abstracts

Title: SOIL SET-UP DUE TO PILE DRIVING

Author: AYOUB, WAFIC TAWFIC

School: TULANE UNIVERSITY, SCHOOL OF ENGINEERING (0494)

Degree: DENG Date: 1981 pp: 480

Source: DAI-B 42/03, p. 1105, Sep 1981

Subject: ENGINEERING, CIVIL (0543)

Abstract: Until recently, predicting the increase in soil resistance during pile driving due to short or lengthy delays was unfeasible. It has often relied on experience and judgement.

Estimating the hammer efficiency for theoretical wave equation studies was disputable. Dynamic measurements performed on piles during pile driving produced a wide varying range of unexplainable efficiency correlations.

From fifteen actual platform case studies comprising over eighty piles, design curves to estimate the average increase in unit friction and the ratio of average increase in unit skin friction to average unit adhesion at the resumption of pile driving as a function of time and depth are provided.

A new concept that explains the variation in dynamic measurement results is also provided.

A new theoretical method to construct the soil resistance during pile driving versus blows/foot curve is included.

It is hoped that the work included in this study will be an incentive for further research work.

Order No: AAC 8003113 ProQuest - Dissertation Abstracts

Title: BEARING CAPACITY OF DRIVEN PILES IN SAND

Author: CASTELLO, RENO REINE

School: TEXAS A&M UNIVERSITY (0803) Degree: PHD Date: 1979

pp: 151

Source: DAI-B 40/08, p. 3854, Feb 1980

Subject: ENGINEERING, CIVIL (0543)

Order No: AAC 7918713 ProQuest - Dissertation Abstracts

Title: PILE DRIVING ANALYSIS OF LARGE DIAMETER HIGH CAPACITY OFFSHORE PIPE PILES.

Author: ROUSSEL, HERBERT JOSEPH, JR.

School: TULANE UNIVERSITY, SCHOOL OF ENGINEERING (0494)

Degree: DENG Date: 1979 pp: 230

Source: DAI-B 40/02, p. 856, Aug 1979

Subject: ENGINEERING, CIVIL (0543)\; ENERGY (0791)

Order No: AAC 7729236 ProQuest - Dissertation Abstracts

Title: WAVE EQUATION STUDY AND RECOMMENDED SPECIFICATIONS FOR THE IMPACT DRIVING OF PRESTRESSED CONCRETE PILES.

Author: CRAPPS, DAVID KENNETH

School: UNIVERSITY OF FLORIDA (0070) Degree: PHD Date: 1977

pp: 425

Source: DAI-B 38/07, p. 3312, Jan 1978

Subject: ENGINEERING, CIVIL (0543)

Order No: AAC 7417277 ProQuest - Dissertation Abstracts

Title: FINITE-ELEMENT ANALYSIS OF DRIVEN PILES.

Author: REIGSTAD, GORDON HANLEY

School: UNIVERSITY OF MINNESOTA (0130) Degree: PHD Date: 1974

pp: 175

Source: DAI-B 35/02, p. 817, Aug 1974

Subject: ENGINEERING, CIVIL (0543)

Order No: NOT AVAILABLE FROM UMI ProQuest - Dissertation Abstracts

Title: THE BEHAVIOR OF STEEL PILES DRIVEN IN CLAY

Author: CLARK, JOHN IVOR

School: TECHNICAL UNIVERSITY OF NOVA SCOTIA (CANADA) (0300)

Degree: PHD Date: 1971

Source: ADD X1971

Subject: ENGINEERING, CIVIL (0543)

Order No: NOT AVAILABLE FROM UMI ProQuest - Dissertation Abstracts

Title: RAPID DRIVING OF THIN HOLLOW CYLINDRICAL PILES INTO PERMAFROST

Author: CHAREST, JACQUES ALEXANDRE

School: COLORADO SCHOOL OF MINES (0052) Degree: PHD Date: 1962

Source: ADD X1962

Subject: ENGINEERING, MINING (0551)

Order No: NOT AVAILABLE FROM UMI ProQuest - Dissertation Abstracts

Title: DRIVING STRESSES IN STEEL BEARING PILES

Author: JANES, ROBERT L.

School: ILLINOIS INSTITUTE OF TECHNOLOGY (0091) Degree: PHD

Date: 1955

Source: ADD W1955

Subject: ENGINEERING, GENERAL (0537)

Order No: AAC 8111453 ProQuest - Dissertation Abstracts

Title: THERMAL SHOCKING AN ELASTIC HALF-SPACE WITH A LASER PULSE

Author: DUNBAR, MARK EDWARD

School: THE UNIVERSITY OF WISCONSIN - MADISON (0262) Degree: PHD

Date: 1981 pp: 151

Source: DAI-B 42/02, p. 686, Aug 1981

Subject: APPLIED MECHANICS (0346)

Abstract: This research determined the thermal and mechanical response of an isotropic elastic half-space subjected to the irradiance of a high-power short pulse laser. The emphasis was toward the short-time response and took into account thermal inertia, the spatial and temporal laser pulse distributions and the uncoupled stress field. Analytically, the solution to the wave equation of heat conduction was determined for one and three dimensions. The singular perturbation problem was pursued, showing that the solution to the one and three dimensional hyperbolic heat conduction equations do become the solutions to the one and three dimensional diffusive heat equations, respectively, in the limit as (tau) (--->) 0('+). The basic thermoelastic equation of motion for a homogeneous, isotropic medium was written in one-dimensional scalar form and combined with the one-dimensional forms of the stress and hyperbolic heat conduction equations using Fourier and Laplace transforms. Elimination of the transformed displacement, u, between these equations and inverting resulted in a computationally simple form for (sigma)(,z) (z,t) and T(z,t). The boundary and initial conditions used were homogeneous for both temperature and displacement, i.e. (PAR-DIFF)(,z)T(0,t) = 0, T(z,0) = (PAR-DIFF)(,t)T(z,0) = 0 and u(0,t) = 0, u(z,0) = (PAR-DIFF)(,t)u(z,0) = 0.

The features of the temperature and stress wave solutions were characterized by both the singular perturbation analysis and the graphs of numerical results.

The thermal wave phenomenon was found to be of importance for short time response of materials at high reference temperatures.

Order No: AAC 8119028 ProQuest - Dissertation Abstracts

Title: INVERSION OF THE FIRST-ORDER EQUATIONS GOVERNING THE PROPAGATION OF SOUND WAVES IN A LAYERED ACOUSTIC MEDIUM

Author: HOWARD, MICHAEL STEVEN

School: INDIANA UNIVERSITY (0093) Degree: PHD Date: 1981

pp: 103

Source: DAI-B 42/03, p. 1057, Sep 1981

Subject: PHYSICS, ACOUSTICS (0986)

Abstract: The inverse scattering problem for a layered acoustic medium is considered from the first-order differential equations of motion, resulting in a vector formulation of the problem, and using a vector form of the inverse scattering methods for Schrodinger's equation of Quantum Mechanics. The result is a vector Marchenko equation.

The differentiability constraints on the acoustic impedance are somewhat relaxed compared to the more standard approach of transforming the wave equation into Schrodinger's equation. The associated potential is the logarithmic derivative of the impedance profile and all potentials in L('1) correspond to physical impedance profiles. This allows the problem of the non-uniqueness associated with bound states of Schrodinger's equation to be resolved in a natural context without having to distinguish between physical and non-physical potentials.

The solution for plane waves at normal incidence is given along with a good approximate solution which is easily obtainable and takes into account transmission losses not included in the normal WKBJ-Born approximation. The lowest order approximation which accounts for multiple reflections is obtained and compared with other approximations in computer model studies using synthetic data.

The exact inversion method is generalized to accommodate impedance profiles which contain step-like discontinuities. This is the final step in removing the twice-differentiable constraint imposed on the impedance profile by the wave equation method.

Also compared in the computer model studies are the effects of missing high frequencies, missing low frequencies and noise in the data. Even under moderately severe noise and high frequency band-limits the inversion gives worthwhile results. However even the slightest low frequency band-limit makes the results almost arbitrarily non-unique.

The left- and right-going component vector of the one-dimensional case is generalized to two dimensions to allow the velocity and density profiles to be resolved separately as functions of depth from non-normal incidence data. This involves a non-linear integral equation to relate the apparent travel times to depth.

Order No: AAC 8021073 ProQuest - Dissertation Abstracts

Title: THE PROPAGATION OF ELASTIC WAVES IN HETEROGENEOUS MEDIA

Author: KELM, JAMES S.

School: UNIVERSITY OF CINCINNATI (0045) Degree: PHD Date: 1980

pp: 152

Source: DAI-B 41/03, p. 1027, Sep 1980

Subject: ENGINEERING, GENERAL (0537)

Abstract: The propagation of elastic waves in heterogeneous media has been the subject of many investigations in recent years. The formulation of the one dimensional problem for finite space and semi-infinite half space is trivial. The governing equation of motion is a second order, hyperbolic, partial differential equation with variable coefficients. Solutions to the problem are particulary difficult to obtain and have generally involved (1) defining special properties for which the governing equations admit known exact solutions, or (2) developing solutions based on simplifying assumptions.

In this dissertation new approximate solutions are presented for the case of general properties in the media. Solutions are developed for a transformed canonical form of the well-known wave equation, referred to as the Klein-Gordon form. These approximate solutions use\; as a basis, the constant coefficient exact solution in their development. Solutions restricted to the wavefront (or arrival time) and far field time domains are developed. Also, a solution is developed for slowly varying coefficients of the Klein-Gordon equation. This solution provides an accurate representation of wave propagation throughout the time domain. The solution is particularly useful in predicting transient pulse propagation and the ensuing local "tailing" or reflection of the wave in media with rapidly varying properties.

The solution techniques presented complement and extend the work available in the literature. The new techniques provide greater insight to the problem of elastic wave propagation in heterogeneous media and can be applied in a reasonably simple manner.

Order No: AAC 8010358 ProQuest - Dissertation Abstracts

Title: CONSTRUCTIVE SOLUTION AND CHARACTERIZATION OF THE INVERSE SCATTERING PROBLEM FOR THE ONE-DIMENSIONAL ACOUSTIC WAVE EQUATION

Author: GREENE, ROBERT REX

School: NEW YORK UNIVERSITY (0146) Degree: PHD Date: 1979

pp: 120

Source: DAI-B 40/11, p. 5297, May 1980

Subject: MATHEMATICS (0405)

Order No: AAC 9212521 ProQuest - Dissertation Abstracts

Title: A FINITE ELEMENT MODEL FOR THE ANALYSIS OF PILE DRIVING (SOIL STRESS)

Author: EL-MABSOUT, MOUNIR EZZAT

School: THE UNIVERSITY OF TEXAS AT AUSTIN (0227) Degree: PHD

Date: 1991 pp: 161

Advisor: TASSOULAS, JOHN L.

Source: DAI-B 52/12, p. 6543, Jun 1992

Subject: ENGINEERING, CIVIL (0543)

Abstract: The feasibility of conducting a detailed analysis of pile driving using a finite element technique is examined in the present study, taking into account the nonlinear behavior of undrained clayey soil and tracing the penetration of the pile into the soil. A three-dimensional model is used for this purpose, which is handled by two-dimensional analysis due to the axisymmetric nature of the problem. A nonlinear time-domain dynamic analysis is performed in which the hammer blows on the pile are represented by a periodic forcing function, and the pile penetration is treated using a frictional contact slide-line algorithm. The pile driveability, integrity, and capacity are discussed, as well as the evolution of the state of stress in the soil and the development of pore-water pressure in the course of driving.

Order No: AAC 9120402 ProQuest - Dissertation Abstracts

Title: DESIGN METHODS FOR DEEP FOUNDATIONS (LATERALLY LOADED PILES, DRILLED SHAFTS)

Author: OOI, PHILLIP SOON KANG

School: VIRGINIA POLYTECHNIC INSTITUTE AND STATE UNIVERSITY (0247)

Degree: PHD Date: 1991 pp: 307

Advisor: DUNCAN, J. M.\; ROJIANI, K. B.

Source: DAI-B 52/02, p. 972, Aug 1991

Subject: ENGINEERING, CIVIL (0543)\; COMPUTER SCIENCE (0984)

Abstract: The first part of this study was the development of a simplified procedure for analyzing laterally loaded piles and drilled shafts. A computer program that can be used to estimate deflections and maximum bending moments in single fixed-head piles (or drilled shafts) and in groups of fixed-head piles (or drilled shafts) was developed. Using this program, charts were developed for estimating deflections and maximum bending moments directly in some of the more common types of single piles and drilled shafts.

The computer program was also used to perform parametric studies of groups of piles and drilled shafts, from which simple formulae for amplifying single pile (or drilled shaft) deflections and moments to those of the group were derived. These simple formulae enable the analysis and design of groups of deep foundations to be done more efficiently. The simplified procedure was used to analyze four well documented and well instrumented case histories of laterally loaded pile groups. Comparison of the predicted and measured results indicate that the simplified procedure provides a method of analyzing laterally loaded groups of deep foundations that yield quite accurate predictions of group deflections and moments in some cases, and values that are conservative in other cases.

The second part of the research was to establish load factor design procedures for incorporating margins of safety for axially loaded deep foundations. Values of performance factors were developed for load factor design of axially loaded driven piles and drilled shafts. This was achieved by analyzing statistical information for loads and resistances, and determining the levels of reliability inherent in current designs, through the use of probability theory. Using these results, a target reliability level in the form of a reliability index was selected. Values of performance factors were then obtained for use with the current AASHTO (1989) code for bridges and the ASCE Standard 7-88 (1990) for buildings and other structures. The issues involved in a probabilistic analysis of groups of deep foundations were also discussed.

Order No: AAC 9025087 ProQuest - Dissertation Abstracts

Title: FINITE ELEMENT DYNAMIC ANALYSIS OF NONLINEAR POROUS MEDIA WITH APPLICATIONS TO PILES IN SATURATED CLAYS

Author: WATHUGALA, GAMAGE WIJESENA

School: THE UNIVERSITY OF ARIZONA (0009) Degree: PHD Date: 1990

pp: 475

Advisor: DESAI, C. S.

Source: DAI-B 51/04, p. 1970, Oct 1990

Subject: ENGINEERING, CIVIL (0543)\; GEOTECHNOLOGY (0428)\; APPLIED

MECHANICS (0346)

Abstract: A basis for developing a general approach to solve geotechnical engineering problems through dynamic finite element analysis of nonlinear porous media is presented. A new series of constitutive models named here as $\delta\sp\*$ series are developed under the general hierarchical single surface (HISS) modeling approach, to include the behavior of, saturated normally consolidated and overconsolidated clay, under drained or undrained, static and cyclic loading conditions. Algorithms for determination of material parameters for these models from laboratory models are also developed. Constitutive parameters for Sabine Clay are obtained using triaxial test results from undisturbed samples and the model is verified by back predicting the laboratory behavior of this clay. Sensitivity analyses for all the material parameters have been also carried out.

Efficient and reliable algorithms for calculating strain increments for given stress increments and vise versa are developed. All the models in the $\delta\sp\*$ series are implemented in the finite element program POROUS which is based on the theory of dynamics of nonlinear porous media. Here a modular approach is used to facilitate easy modification of all the functions associated with these models (yield function, potential function, hardening function and interpolation functions).

Complete test procedure for field load tests on two pile segments (3 inch and 1.72 inch) are numerically simulated and compared with field measurements. Initial stresses before pile driving are estimated using results of s self boring pressuremeter test on the site. Strain distributions just after pile driving are evaluated using the strain path method. The effective stress distribution is obtained by integrating constitutive equations for given strain paths. Corresponding total stresses and pore pressure distributions are obtained using the computer program POROUS. Consolidation after pile driving and all the static and cyclic tests followed are also simulated using the program POROUS. The predicted normalized pore pressure dissipation curve matches the field behavior. This analysis provides good predictions of shear transfer from which the pile capacity can be evaluated. Even though the variation of pore pressure during a cycle is not matched exactly, the accumulation of pore pressures are predicted well.

The demonstrated ability of dynamic finite element analysis of nonlinear porous media, to simulate slow consolidation and cyclic load tests provides a basis for developing a general approach for solving geotechnical engineering problems.

Order No: AAC 1342277 ProQuest - Dissertation Abstracts

Title: DYNAMIC RESPONSE OF SIMPLE PILE-STRUCTURE SYSTEMS

Author: KHURANA, SANDEEP

School: RICE UNIVERSITY (0187) Degree: MS Date: 1990 pp: 83

Advisor: VELETSOS, A. S.

Source: MAI 29/02, p. 301, Summer 1991

Subject: ENGINEERING, CIVIL (0543)

Abstract: This dissertation is composed of two parts. In the first part, a comprehensive study is made of the harmonic response of a rigid mass or a mass-sprint system supported on a pile driven in a homogeneous elastic medium. The objectives are to assess the effects of the various factors that affect the response of the system. The second part deals with the harmonic response of rigid and elastically supported simple systems on pile groups. The main aim is to incorporate pile-to-pile interaction and investigate its effect on response of such systems.

The system is shown to respond essentially as a viscously damped single-degree-freedom oscillator. Plots are presented for the amplification factor and the resonant frequency of the system. With the information presented herein significant aspects of the dynamic response of vertically and laterally excited simple structure-pile systems may be evaluated readily.

Order No: AAC 9031427 ProQuest - Dissertation Abstracts

Title: SOIL STRESS FIELD AROUND DRIVEN PILES (PILES)

Author: ALLARD, MARIE-AGNES

School: CALIFORNIA INSTITUTE OF TECHNOLOGY (0037) Degree: PHD

Date: 1990 pp: 197

Source: DAI-B 51/06, p. 3105, Dec 1990

Subject: GEOTECHNOLOGY (0428)\; ENGINEERING, CIVIL (0543)

Abstract: The description, equipment, and results of a series of pile-driving experiments conducted in a centrifuge using a model pile driven in dry sand are presented.

The work was conceived on the basis of the modelling of a soil-structure system under an artificially generated gravitational field, and motivated by the need for experimental data for a better understanding of the complex phenomena involved in the pile-soil interaction during driving. The behavior of the pile itself has been the focus of more attention in the past, but few full-scale or model experimental results have been obtained to the present concerning the soil stress field during pile driving. These are necessary for comparison with analytical and theoretical work. The work presented here appears to be the first attempt to obtain dynamic response of the soil during driving. The objective was to obtain a good understanding of the physical phenomena occurring in the soil and pile during driving.

In order to achieve these objectives both dynamic (transient) and static responses of the soil and pile were measured by means of transducers: accelerometers and strain gages for the pile, pressure transducers for the soil. In particular, the relations between static and dynamic data were explored, which resulted in the modelling of the soil-transducer interaction with a non-linear, history-dependent, model.

Results were obtained regarding pile dynamics, soil dynamics, and soil stress field (radical and vertical distribution, stress contours). Both linear and soil-cell assumptions were used, which enabled a comparison between the two, leading to an estimate that each constitutes a bound of the real stress field, with the linear giving the higher, and the non-linear the lower bound, and the true stress being closer to the lower bound.

The soil response during driving is obtained, filling the gap in the study of the pile-soil system, where only the pile response was known. Recommendations for further work and better experimental procedures are given.

Order No: AAC DX91682 ProQuest - Dissertation Abstracts

Title: THE BEHAVIOUR OF AN ANCHORED SHEET PILE WALL IN GRANULAR SOIL. (VOLUMES I AND II) (ANCHOR LOADS, PILE DISPLACEMENTS)

Author: WILLIAMS, SHON GWYN OWEN

School: HERIOT-WATT UNIVERSITY (UNITED KINGDOM) (5018)

Degree: PHD Date: 1989 pp: 460

Source: DAI-B 51/11, p. 5485, May 1991

Subject: ENGINEERING, CIVIL (0543)

Abstract: Available from UMI in association with The British Library.

Recently anchored flexible walls have become more commonly used to facilitate the construction of cuttings in areas where only limited space is available, such as for roads in urban areas. Much theoretical work, and practical work in the form of model testing has been performed to investigate the behaviour of these walls\; however, there has been little full scale testing carried out to validate the findings of this work. Therefore there is a need for full scale investigations of flexible anchored walls.

The work contained in this thesis is primarily concerned with the field investigation on an anchored sheet pile wall which formed part of the temporary works for the A1 improvement scheme at Hatfield.

The types of instrumentation developed for the project are presented in detail, particularly concerning the results of a trial drive performed to investigate which instrumentation would be least affected by pile driving and what type of protection to the instrumentation should be provided.

The results determined from the instrumentation are presented and discussed in detail. The measured pile displacements, bending moments and anchor loads along horizontal and vertical ground movements are presented for all stages of construction.

From a comparison of bending moments determined from the strain data and the pile deflected shapes, it has been shown that the "effective stiffness" and ultimate bending strength of the piles (interlocked at centre of gravity) were most likely below their quoted values.

Comparison of the measured bending moments with those determined from various design methods is made. This showed the Free Earth Support methods to predict moments three to four times larger than those measured. Results from the Fixed Earth Support methods and Row's method of design however, showed reasonable agreement with those measured.

Finally the results of a finite element analysis of the wall are presented. From this the bending moments and pile deflections determined are seen to be considerably smaller than those measured. It is considered that this may be due to the programme overestimating the degree of arching occurring behind the wall.

Order No: NOT AVAILABLE FROM UMI ProQuest - Dissertation Abstracts

Title: SKIN FRICTION OF PILES IN SANDS--INFLUENCE OF THE SAND COMPRESSIBILITY AND THE SHAPE OF THE TIP [FROTTEMENT LATERAL DES PIEUX DANS LES SABLES--INFLUENCE DE LA COMPRESSIBILITE DES SABLES ET DE LA GEOMETRIE DE LA POINTE]

Author: SID-AHMED, RACHID

School: UNIVERSITE DE NANTES (FRANCE) (0777) Degree: DO

Date: 1989 pp: 186

Source: DAI-C 50/04, p. 760, Winter 1989

Language: FRENCH

Subject: ENGINEERING, CIVIL (0543)

Publisher: EDITIONS TECHNIP, 27, RUE GINOUX - 75737 PARIS CEDEX 15, FRANCE

Location: INSTITUT FRANCAIS DU PETROLE, B.P. 311 - 92506 RUEIL MALMAISON CEDEX, FRANCE

Abstract: Calcareous sands encountered in many zones of petroleum activity often cause difficult problems in the design and installation of foundation piles. Skin friction mobilized by piles driven into compressible calcareous sands is very low, often negligible. Drilled and grouted piles represent an interesting alternative technique, but with a much higher realization cost.

This thesis is part of a general study into the behaviour of foundations on calcareous sands undertaken by IFP and industrial associates for the past ten years. The work, essentially experimental, deals with the analysis of the influence of calcareous sand characteristics upon the skin friction of driven piles or grouted piles. Different types of laboratory tests were carried out in a pressure tank, calibration chamber and using a bidimensional model.

The results show: (1) the non-uniformity of skin friction along a driven pile, being greatest at the tip, with the skin friction dependent upon the tip shape\; (2) the preponderant influence of sand compressibility on horizontal stresses--the coefficient of lateral earth pressure decreases when sand compressibility increases\; and (3) the skin friction mobilized by drilled and grouted piles essentially depends on the shape (angularity) and size of the sand grains as well as the roughness of the grout sheath.

Order No: NOT AVAILABLE FROM UMI ProQuest - Dissertation Abstracts

Title: DYNAMIC AND STATIC TESTING OF LARGE MODEL PILES IN SAND (DYNAMIC TESTING)

Author: BERNARDES, GEORGE DE PAULA

School: UNIVERSITETET I TRONDHEIM (NORWAY) (0941) Degree: DRING

Date: 1989 pp: 405

Source: DAI-C 51/02, p. 312, Summer 1990

Subject: ENGINEERING, MARINE (0547)

ISBN: 89-7119-147-0

Publisher: UNIVERSITY OF TRONDHEIM, NORWEGIAN INSTITUTE OF TECHNOLOGY, N-7034 TRONDHEIM-NTH, NORWAY

Abstract: Steel jackets in the North Sea are usually founded on large pipe piles of diameters 1.0 to 2.5 and lengths in the scale of 100 m. Both pile capacities and required driving energies are about 100 times larger than for ordinary onshore piles. The pioneer period around 1970 onward forced a rapid development of larger driving equipment and improved theories for forecasting capacities and drivability. This thesis represents a further advancement in the static and dynamic basis for design of such large offshore piles.

The author has carried out an extensive experimental work in a 50 m$\sp3$ large test tank. Large model piles were instrumented for recording the behaviour during static and dynamic loading, and electronically registered data facilitated rational interpretation and plotting procedures.

The dynamic part of the thesis is based on wave propagation theories. The basic elements of the theory are presented and critically evaluated. The instrumentation, the data logging system, the test procedures and the interpretation procedures, were developed and tailor-made to a large extent by the author. As such it is a first-time event of its kind in our country.

The static capacity test results are compared with several existing procedures used in practical design. A fair scatter is registered, indicating that there is room for improvement in narrowing the gap, preferably along a deformation approach rather than a fixed capacity approach.

A chapter on important drivability aspects has been based both on conventional, simple driving formuli, and on large computer programs such as WEAP.

Order No: AAC 8912060 ProQuest - Dissertation Abstracts

Title: DEVELOPMENT AND TESTING OF A DEVICE CAPABLE OF PLACING MODEL PILES BY DRIVING AND PUSHING IN THE CENTRIFUGE

Author: GILL, JOHN JOSEPH

School: UNIVERSITY OF FLORIDA (0070) Degree: PHD Date: 1988

pp: 320

Advisor: TOWNSEND, FRANK C.

Source: DAI-B 50/03, p. 1047, Sep 1989

Subject: ENGINEERING, CIVIL (0543)

Abstract: Elastic wave propagation and the practical aspects of pile driving are discussed to develop an understanding of which aspects of pile driving must be modeled most precisely in the centrifuge. The scaling laws are developed. Design and construction of a 5-g-ton (110 g) centrifuge are presented. Construction details of the model pile placement device are discussed. The placement device has the capability of driving individual piles and can model the energy input of any single acting pile driver. The placement device can also push individual and group piles through the application of up to 1.5 million scale pounds. Static load tests can be conducted with the device. All computer software necessary for the driving, pushing, and load testing of model piles is outlined. Discussion includes all related software for model pile calibration (strain gage response to loading) and load test interpretation (deBeer method). A method of strain gaging the model piles is presented. A test series is conducted at 69.8 and 86.0 g's involving the pushing of individual, group of four, and group of five model piles based on a 35-foot long prototype pile (group) driven 30 feet into saturated fill. All model tests are conducted on dry granular soil with relative density varying between 45% and 70%. All models are load tested with several being subjected to tensile pullout tests. Individual model piles are driven permitting the comparison between the load-bearing capacity of drive and pushed models.

The placement device is shown to be precise and accurate in the measurement of pile displacement and resistance to penetration. Driven individual model piles are found to have lower initial loading moduli but similar ultimate capacity to the those of pushed models. Differences are attributed to disturbance of the model during placement of load cell on the model butt prior to load testing. Bearing capacity of the model pile tips are not altered by scale effects\; however, skin friction on the sidewalls decreases exponentially as test g level is increased. The model group piles demonstrate an efficiency of 1.17 with a group efficiency of 1.0 being considered conservative for group models placed in granular soils.

Order No: AAC 8912676 ProQuest - Dissertation Abstracts

Title: AN EXPERIMENTAL AND NUMERICAL STUDY OF IMPACT DRIVING OF OPEN-ENDED PIPE PILES IN DENSE SATURATED SAND

Author: UGAZ, OSCAR GUILLERMO

School: UNIVERSITY OF HOUSTON (0087) Degree: PHD Date: 1988

pp: 159

Advisor: O'NEILL, MICHAEL W.

Source: DAI-B 50/04, p. 1556, Oct 1989

Subject: ENGINEERING, CIVIL (0543)

Abstract: An important task in the design and installation of open-ended steel pipe piles in saturated dense sand is the selection of the piling and the driving system. In order to do this, it is necessary to predict, in some rational manner, the behavior of the soil plug that forms inside the pile when it is driven into the sand. Consequently, an experimental and analytical study was conducted in order to understand better the plug behavior during static and dynamic driving conditions and how this behavior is affected by the pile/sand angle of friction. The experimental study consisted of driving a model pipe pile, simulating a full-sized pile, with different values of the pile/sand angle of friction, into a pressurized chamber filled with sand and performing static load tests after driving. Measurements of the pile top acceleration and force versus time were taken during driving while the plug movement was monitored after each driving blow. The analytical study employed a finite element model of the pile/chamber system, with the sand being modeled as an isotropic hardening elasto-plastic material. The finite element model was verified by subjecting the pile top in the finite element model to a dynamic force equal to force versus time signals recorded during testing, and the computed pile and plug movements were compared to those taken during testing. The finite element model was also used to perform a simulation of the static load tests with the computed results being compared to those obtained during testing. Analysis of the results indicate a significant influence of the pile/sand angle of friction and pile penetration in the plug length and nondimensional curves are presented to estimate this length. Also, it was found that, for the range of pile/sand angles of friction studied, the plug and pile move in phase with each other during driving.

An approximate procedure, simple enough to apply in routine design practice, based on the analytical model, is presented to estimate the contribution of the plug, skin friction and bearing to the static axial capacity of an open-ended steel pipe pile driven in dense saturated sand.

Order No: AAC 8900226 ProQuest - Dissertation Abstracts

Title: DYNAMIC IMPEDANCES OF SOIL LAYERS AND PILES

Author: DOTSON, KIRK WAYNE

School: RICE UNIVERSITY (0187) Degree: PHD Date: 1988 pp: 216

Advisor: VELETSOS, ANESTIS S.

Source: DAI-B 49/10, p. 4445, Apr 1989

Subject: ENGINEERING, CIVIL (0543)

Abstract: The objectives of the studies reported in this dissertation are: (1) to evaluate the dynamic impedance of horizontally inhomogeneous, thin soil layers and of piles embedded in such layers\; and (2) to provide improved insight into the response of vertically excited piles bearing on a stratum of arbitrary stiffness.

The dissertation consists of two major parts. The first part, reported in Chapters 2 through 5, deals with the analysis of the impedances of inhomogeneous soil layers. Vertical, torsional, and horizontal modes of vibration are investigated. Primary emphasis is placed on assessing the effect of the radial variation of the soil shear modulus.

The numerical solutions for layer impedances are obtained for several different radial variations of the shear modulus, and are compared with each other and that applicable to a homogeneous soil. The importance of the inertial effects of the soil zone near the pile and the consequences of discontinuous radial variations of soil modulus are clarified.

The layer impedances are then used to evaluate the manner and extent to which the dynamic stiffness and damping capacity of piles may be influenced by the weakening of the soil near the pile-soil interface.

The second part of this dissertation, comprised of Chapters 6 and 7, deals with the dynamic impedance of a vertically excited pile which is driven through a uniform layer and bears on a stratum of finite depth and arbitrary stiffness. The solution takes due account of the variation of the soil reactions with depth by expressing them in terms of the characteristic functions of the two-layer medium.

Comprehensive parametric studies are made to assess the effects of the various parameters involved and to evaluate the applicability of the solution based on the idealization of the soil medium as a series of thin horizontal layers. Comparisons are also made with previously reported solutions for statically and dynamically loaded piles. The results provide improved insight into the mechanism of soil-pile interaction.

Order No: AAC D-81537 ProQuest - Dissertation Abstracts

Title: THE AXIAL CAPACITY OF DRIVEN PILES IN CLAY

Author: COOP, MATTHEW R.

School: UNIVERSITY OF OXFORD (UNITED KINGDOM) (0405) Degree: PHD

Date: 1987 pp: 265

Source: DAI-B 49/04, p. 1299, Oct 1988

Subject: ENGINEERING, CIVIL (0543)

Abstract: Available from UMI in association with The British Library. Requires signed TDF.

An instrumented model pile was used to investigate the fundamental behaviour in clay soils of driven cylindrical steel piles used for offshore structures. Four test-bed sites were chosen\; two in stiff heavily overconsolidated clays, and two in normally/lightly overconsolidated clays.

Data from these sites confirm that a residual shear surface is formed along the pile during installation, the location of which relative to the shaft surface appears to depend on the shaft roughness. Comparisons with other site investigation data and cavity expansion theoretical predictions indicate that stress relief immediately behind the pile tip during driving gives rise to total radial stresses and pore pressures measured on the pile shaft which are lower than predicted. This stress relief is particularly severe in the stiffer clays. The data did however show that the installation total radial stresses and pore pressures are governed by the initial in-situ stresses and undrained shear strength as is predicted by the theory.

During reconsolidation, pore pressures close to the instrument rise initially in all clays, and radial effective stresses drop. The slow recovery in radial effective stress during the later stages of reconsolidation was in some cases insufficient to return it to levels recorded during installation. However, the generation of negative pore pressures during undrained loading increased the radial effective stress and shaft friction at failure. This effect is particularly important in the normally consolidated clays, and is responsible for the set-up of shaft capacity seen in such clays, which might not be observed if the loading were drained. The observed behaviour was therefore quite different from the monotonic increase in radial effective stress during reconsolidation, followed by decrease during undrained loading which was expected from a review of current theory.

Order No: AAC 8807596 ProQuest - Dissertation Abstracts

Title: CAPACITY OF DRIVEN PILES IN COHESIONLESS SOILS INCLUDING RESIDUAL STRESSES

Author: DARRAG, AHMAD AMR

School: PURDUE UNIVERSITY (0183) Degree: PHD Date: 1987 pp: 418

Advisor: LOVELL, C. W.

Source: DAI-B 49/03, p. 849, Sep 1988

Subject: ENGINEERING, CIVIL (0543)

Abstract: Static formulas based on limit equilibrium theories often provide misleading predictions of pile capacity in cohesionless soils. Researchers have been working within the last few years to improve empirical prediction methods. However, even the most recent methods neglect one or more of four factors\; namely: residual stresses due to pile driving, actual soil parameters prior to failure, mean normal stress levels, and stress history.

Available indirect methods used for residual stress measurement are not accurate. Furthermore, no accurate method for their prediction, except the wave equation, is available. Therefore, in this dissertation a new method that takes into account all related parameters for residual stress prediction was developed. It was shown that the existence of these stresses is the principal reason for observing limit values of pile tip and shaft capacities.

Due to high stress levels beneath the pile tip prior to failure, the initial angle of shearing resistance may be substantially reduced. This may result in serious overestimation of the pile tip capacity, especially in dense sands, if the initial angle were used. In this research, a procedure was developed to account for this behavior.

For many of the available methods, the vertical overburden pressure was used for predicting pile capacity. However, this capacity is actually affected by the mean normal stress. Correlations in terms of this stress are proven to be superior to those produced when the overburden pressure was used.

Stress history was found to have a major effect on pile capacity in both reducing soil compressibility and increasing lateral pressure on the pile shaft, and hence increasing the pile capacity. These effects have not been taken into account in available prediction methods.

In this research, available load test data were properly adjusted for residual stresses, and were then used to develop a new empirical prediction method for driven piles in cohesionless soils. The new method takes into account parameters at failure, mean normal stress, and stress history. This method was indicated to be superior to other available methods by comparison with actual measurements.

Order No: AAC 8721555 ProQuest - Dissertation Abstracts

Title: A MODEL STUDY OF PILE GROUP RELAXATION FOR PILES BEARING IN DISCONTINUOUS ROCK

Author: SCHURING, JOHN ROBERT, JR.

School: STEVENS INSTITUTE OF TECHNOLOGY (0733) Degree: PHD

Date: 1987 pp: 248

Source: DAI-B 48/08, p. 2426, Feb 1988

Subject: ENGINEERING, MARINE (0547)

Abstract: This thesis investigates the relaxation of pile groups driven into bedrock using model simulation. Model piles were driven into a simulated discontinuous rock mass with an impact hammer. Relaxations were measured both as a loss of load capacity under static loading, and also as additional penetration during redriving. Similitude of the model experiments with the full-scale condition was verified using dimensional analysis and by comparison with actual field data.

The model piles had nominal diameters of 1 inch and the simulated rock blocks had an average compressive strength of 3200 psi. Test measurements were made electronically and recorded on a microcomputer controlled data acquisition system.

The effects of several experimental parameters on the degree of relaxation were examined for pipe piles. Correlations with driving order, relative tip penetration, and vertical heave were developed. The degree of relaxation was found to be inversely proportional to pile spacing and group size. The maximum radius of influence for a five pile group was estimated by extrapolation to be 8 to 10 pile diameters. Group efficiencies were computed taking into account the observed relaxations. Up to 40% reductions in group load capacity were estimated for relaxed pile groups compared with unrelaxed groups.

A limited amount of testing was performed with model H-piles. H-piles were found to be much less susceptible to relaxation than pipe piles, but they exhibited significantly less ultimate load capacity. The primary mechanisms of relaxation in the rock mass were identified as: (1) fracturing and pulverization\; (2) lateral and vertical displacement\; (3) reduction in lateral stress\; and (4) vibration.

The dynamic bearing capacity of the pipe piles during driving was evaluated using both force-velocity integrations and the wave equation. The observed dynamic capacity ranged between 2.0 and 3.0 times the unconfined compressive strength of the model rock mass.

Recommendations for detecting and remediating relaxation in the field are presented based on the case histories and the results of the experimental study. Suggestions are made for future research in the areas of pile group relaxation and rock bearing capacity.

Order No: AAC D-84259 ProQuest - Dissertation Abstracts

Title: BEHAVIOUR OF LATERALLY LOADED PILES

Author: KAN, JIM HOU-SEK

School: UNIVERSITY OF MANCHESTER (UNITED KINGDOM) (0618)

Degree: PHD Date: 1987 pp: 478

Source: DAI-B 49/11, p. 4980, May 1989

Subject: ENGINEERING, MATERIALS SCIENCE (0794)

Abstract: Available from UMI in association with The British Library. Requires signed TDF.

A series of centrifuge experiments has been carried out to investigate the behaviour of piles under lateral load in the Peter W. Rowe Laboratory, University of Manchester.

The model piles used were 25.4mm diameter hollow tubes of varying thickness with strain gauges mounted internally in order to measure moment/depth profiles down the pile under static and/or cyclic lateral loads. Because of the perceived need to model field installation conditions as accurately as possible, in particular the lateral stress distribution following installation, these model piles were driven 'in-flight' aboard the centrifuge and subsequently loaded laterally at either 25g or 44g, simulating field piles up to 1m in diameter and some 15m in length.

The centrifuge test results were then analysed using a fifth degree $\beta$-spline curve fitting approach. Comparison with standard design procedures, including subgrade reaction, elastic analysis and p-y curves were also carried out. For tests in sand, it was found that the empirical p-y curve approach (Reese et al, 1974) was sufficient for design purpose. However, for tests in clay, a new design procedure is proposed to give more appropriate solutions.

Numerical modelling of the laterally-loaded pile was also performed with the aim of developing simple but yet sufficiently accurate models for practical engineering. A simplified approach using one-dimensional analysis was proposed. Results from numerical models and centrifuge tests agreed reasonably well with each other.

Order No: NOT AVAILABLE FROM UMI ProQuest - Dissertation Abstracts

Title: THE DEVELOPMENT OF SHAFT FRICTION AND END BEARING RESISTANCE FOR DYNAMICALLY DRIVEN MODEL PILES

Author: LAKE, GWYN CHARLES

School: COUNCIL FOR NATIONAL ACADEMIC AWARDS (UNITED KINGDOM)

(0935) Degree: PHD Date: 1986 pp: 365

Source: DAI-C 49/01, p. 155, Spring 1988

Subject: ENGINEERING, CIVIL (0543)

Location: POLYTECHNIC OF WALES LIBRARY, TREFOREST, PONTYPRIDD, MID GLAMORGAN, CF37 1DL, S. WALES

Abstract: This thesis describes a laboratory investigation of the behaviour of a 60 mm diameter tubular steel model pile dynamically driven into sand and into sand overlying clay. The soil was placed and instrumented under controlled conditions in a 3 m diameter concrete tank 3 m deep.

A pilot study was initially undertaken using a 38 mm pile to check the proposed static and dynamic instrumentation. A sophisticated control programme was then developed for the main tests using an Orion Data Logger interfaced with a Commodore PET micro computer. The static load data was stored on discs whilst the transient data was recorded on magnetic tape for later analysis.

A pneumatically controlled rig was designed for driving the piles. The piles were driven from the surface adding sections at selected intervals. Inclinometers were installed in the soil to monitor vertical movements. The density of the soil was also measured at selected points at the end of the tests.

The pile was driven to an embedded depth of 2 metres and then test loaded using the conventional CRP, MTL and Pull Out tests. The load distribution along the pile, together with the vertical movement of the soil was monitored at all stages. Changes in the shear and vertical stresses at the sand clay interface were also monitored and the final deformation of the clay beneath the pile tip.

The data showed: (1) The pile top impact force was dependant on ram impact velocity only. (2) The transient forces at the pile tip could be less than equal to or greater than the impact force depending on the nature of the bearing surface. (3) The stress transfer curves exhibited a large value at shallow depth diminishing in value towards the toe. (4) Vertical sand displacement decreased with increasing depth and radius. (5) Insitu density increased towards the pile shaft by an appreciable amount. (6) Soil movements were recorded across the sand clay interface during driving and test loading. (7) Dragdown of sand into the clay along with a wedge of sand which preceded the pile tip was also observed.

A theoretical approach for predicting static bearing capacity using the dynamic equations of motion and dynamic measurements is also outlined and compared with the authors experimental results. The agreement between experimental and theoretical thus achieved are encouraging.

Order No: AAC 9122687 ProQuest - Dissertation Abstracts

Title: DISCRETE A PRIORI ESTIMATES FOR THE INVERSE PROBLEM OF REFLECTION SEISMOLOGY (DOWNWARD CONTINUATION METHOD)

Author: YEUNG, WING KWONG

School: UNIVERSITY OF CALIFORNIA, LOS ANGELES (0031) Degree: PHD

Date: 1991 pp: 136

Advisor: BUBE, KENNETH P.\; ENGQUIST, BJORN

Source: DAI-B 52/03, p. 1486, Sep 1991

Subject: MATHEMATICS (0405)\; ENGINEERING, PETROLEUM (0765)

Abstract: We study numerical methods for the one-dimensional inverse problem of reflection seismology. An impulsive plane wave in pressure is applied to the surface of a stratified elastic half space and the resulting particle velocity is measured at the surface. The characteristic impedance of the medium is to be recovered as a function of time.

We consider the downward continuation method and show a priori estimates of the impedance and its differences which depend only on the measured particle velocity at the surface. A convergence proof of the downward continuation method is presented by applying the a priori results.

We also prove the second order convergence of the forward problem by using energy estimates. Finally, we generalize the convergence result for the downward continuation method to the wave equation with variable wave speed. We conclude with examples to show the convergence of the downward continuation method for this wave equation.

Order No: AAC 9213291 ProQuest - Dissertation Abstracts

Title: SOLUTION OF FUNCTIONAL EQUATIONS OF PESKIN COCHLEA MODEL AND SOME RESULTS ON MODEL EQUATIONS OF INCOMPRESSIBLE FLUID FLOW (FLUID FLOW)

Author: YANG, YAHAN

School: NEW YORK UNIVERSITY (0146) Degree: PHD Date: 1991

pp: 94

Advisor: LAX, PETER D.

Source: DAI-B 52/12, p. 6447, Jun 1992

Subject: MATHEMATICS (0405)

Abstract: This thesis is in three parts. In chapter 1 we study the behavior of local energy function for outgoing solution of linear wave equation in higher dimension. A simple example is found where energy in a fixed ball might increases at some time which is sharply different from one dimensional case. Chapter 2 is a new solution method for functional equations related to Peskin's cochlea model. In the study, solutions of functional equations are intimately connected to spectral theory of certain self-adjoint operators, where we use eigenfunctions to model the typical oscillatory behavior observed in cochlea wave. Chapter 3 is concerned with analytical model equations of incompressible fluid flow. Opposite to previous results of Schochet, we find conditions on initial data which guarantee that solutions of viscous model equation remain smooth when solutions of inviscid equation blow up. In section 3.2 we formulate a model problem for question of uniqueness of Leray-Hopf weak solutions to Navier-Stokes system. A global existence result is obtained in section 3.3.

Order No: AAC 8919450 ProQuest - Dissertation Abstracts

Title: AN ENTROPY-BASED APPROACH TO NONLINEAR STABILITY

Author: MERRIAM, MARSHAL LOCKHART

School: STANFORD UNIVERSITY (0212) Degree: PHD Date: 1989

pp: 214

Advisor: FERZIGER, J. H.

Source: DAI-B 50/06, p. 2508, Dec 1989

Subject: ENGINEERING, AEROSPACE (0538)\; MATHEMATICS (0405)\;

COMPUTER SCIENCE (0984)

Abstract: Many numerical methods used in Computational Fluid Dynamics (CFD) incorporate an artificial dissipation term to supress spurious oscillations and control non-linear instabilities. The same effect can be accomplished by using upwind techniques, sometimes augmented with limiters to form Total Variation Diminishing (TVD) schemes. An analysis based on numerical satisfaction of the second law of thermodynamics allows many such methods to be compared and improved upon. For example, certain TVD schemes tend to "square" a smooth pulse. These can be detected a priori by their negative entropy production rates.

A non-linear stability proof is given for discrete scalar equations arising from a conservation law. Solutions to such equations are bounded in the $L\sb2$ norm if the second law of thermodynamics is satisfied in a global sense over a periodic domain. It is conjectured that an analogous statement is true for discrete equations arising from systems of conservation laws.

Stability in the $L\sb2$ norm is not sufficient to exclude expansion shocks, oscillations, and other unphysical phenomena. Numerical experiments suggest that a more restrictive condition, a positive entropy production rate in each cell, is both necessary and sufficient to exclude such phenomena.

Construction of schemes which satisfy this condition is demonstrated for linear and non-linear wave equations and for the one dimensional Euler equations. For the linear wave equation all schemes which satisfy a cell entropy inequality are formally TVD. The converse is not true. The scheme for the Euler equations makes use of a remarkable identity to avoid the usual frozen coefficient approximation. Results are shown.

Since this form of dissipation is based on classical thermodynamics, it extends naturally to all types of fluid dynamics problems. In particular, artificial dissipation requirements for the Navier-Stokes equations, compressible and incompressible, may be quantitatively assessed.

Most existing forms of dissipation (including those mentioned above), treat problems in two and three dimensions as a sequence of one dimensional operators. The present work does not require this approximation, and therefore extends more naturally to unstructured meshes. It holds promise for use with multigrid and grid refinement methods.

Order No: AAC 8802910 ProQuest - Dissertation Abstracts

Title: MEAN FLOW EFFECTS ON THE PERFORMANCE OF PERFORATED TUBE SILENCERS AND DISSIPATIVE SILENCERS CONTAINING BULK ABSORBENT

Author: CHANG, INGJIUN DANIEL

School: UNIVERSITY OF MISSOURI - ROLLA (0135) Degree: PHD

Date: 1987 pp: 168

Source: DAI-B 48/11, p. 3387, May 1988

Subject: ENGINEERING, MECHANICAL (0548)

Abstract: Theoretical and experimental studies are described, for determining the sound transmission loss of silencers in the exhaust systems of internal combustion engines. Dissipative silencers lined with bulk-reacting sound absorbent and reactive silencers with perforated tubes are considered\; mean gas flow is present in both cases and the effects of intense sound pressure are included in the latter case.

A microstructure model is first described, in order to determine the effects of internal mean flow on the acoustical properties of porous materials. Modified expressions, thus obtained, for the bulk acoustic properties are then used in the study of dissipative silencers. The acoustic transmission loss data based on the theoretical study are in good agreement with experimental results for a test silencer. Internal mean flow in the porous material is found to have a drastic effect on the sound attenuation in ducts with bulk-reacting liners, even for internal flow speeds as small as 0.5 m/s.

An implicit, time-dependent, finite difference approximation is developed to solve a quasi-one dimensional acoustic wave equation for flow ducts with yielding walls. This numerical method is applied to determine the acoustic transmission loss of perforated tube silencers in the presence of mean flow, provided a linear sound field is assumed. Measured and predicted data of the transmission loss of two test silencers are compared and are found to be in excellent agreement. The results based on the present time domain scheme and an equivalent frequency domain analysis are also compared and it is seen that the numerical time domain method gives superior predictions of the transmission loss.

Order No: AAC 7202393 ProQuest - Dissertation Abstracts

Title: BEHAVIOR OF AXIALLY LOADED DRILLED SHAFTS IN BEAUMONT CLAY

Author: O'NEILL, MICHAEL WAYNE

School: THE UNIVERSITY OF TEXAS AT AUSTIN (0227) Degree: PHD

Date: 1970 pp: 792

Source: DAI-B 32/07, p. 3934, Jan 1972

Subject: ENGINEERING, CIVIL (0543)

Order No: AAC 8624831 ProQuest - Dissertation Abstracts

Title: THE CHANGE IN SOIL STRESS STATE DURING AND AFTER THE INSTALLATION OF A GROUP OF PILES IN CLAYS

Author: LEE, HEI YIP

School: UNIVERSITY OF CALIFORNIA, BERKELEY (0028) Degree: PHD

Date: 1986 pp: 251

Source: DAI-B 47/07, p. 3032, Jan 1987

Subject: ENGINEERING, CIVIL (0543)

Abstract: This dissertation describes the results of an investigation of the change in effective stress state during and after the installation of a group of piles in clay. Particular emphasis was placed on evaluating the change in total stress and pore pressure with time due to phenomena such as pile installation, pile-soil-pile interaction, stress relaxation, and consolidation. The general form of such a time-dependent, soil-structure interactive problem involves two discrete and fundamentally different sub-problems\; namely a stress equilibrium problem and a pore pressure propagation problem that interact with time. The solution of this equilibrium-propagation problem is achieved by advancing through time in increments, solving the individual sub-problem repeatedly. In each time increment the excess pore pressure dissipation in three-dimensions or generation due to pile installation is evaluated (propagation problem)\; at the end of the time increment, the soil stress states due to the changes in pore pressures from the propagation problem as well as stress relaxation and pile-soil-pile interaction are assessed (equilibrium problem).

Cylindrical cavity expansion theory and critical state soil mechanics concepts were used as tools in arriving at the state of stress in the clay immediately after pile installation. Pile-soil-pile interaction during driving of adjacent piles was modeled by a modified cavity expansion theory. A general stress-strain-time relationship was used to model stress relaxation behavior of the clay. These changes in stresses and pore pressures were then used as input to the general equilibrium-propagation problem in each time increment. Thus by advancing through time, a steady-state, long-term condition is finally reached.

A well-documented model pile group test with pore pressure measurements during installation was used to evaluate the numerical procedure. Due to the unavailability of long-term effective stress measurements in pile group tests, two numerical examples were used in order to make stress state comparisons between a single pile and pile group behavior. Practical recommendations were generated from the results of these examples.

Order No: AAC 8701619 ProQuest - Dissertation Abstracts

Title: PROBABILISTIC PREDICTION OF FRICTION PILE CAPACITIES

Author: SIDI, INDRA DJATI

School: UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN (0090)

Degree: PHD Date: 1986 pp: 346

Source: DAI-B 47/12, p. 4993, Jun 1987

Subject: ENGINEERING, CIVIL (0543)

Abstract: The probability of failure of friction pile foundations in clay deposits subjected to axial loads is evaluated. The probabilistic procedure provides a consistent method for the modeling, analysis, and updating of uncertainties that are involved in the determination of pile capacity. Results are used to demonstrate a probability - based procedure for the design of pile foundation.

Factors contributing to the variability of friction capacity were identified. Detailed uncertainty analysis of each of these factors is then performed based on extensive review of literature and analysis of a large base of well-conducted pile load test data.

Random field model is used to describe inherent spatial variability of soil properties. When several soil layers are encountered, soil properties between layers are assumed to be statistically independent. The case of random occurrence of an irregular soil material is also considered. In all cases, the overall effect of the inherent variability may be conveniently treated by defining an equivalent soil deposit consisting of single homogeneous material. For pile groups and pile system, correlation characteristics between soil properties and layer thicknesses, at various pile locations are considered in determining the degree of correlation between capacities of piles in a group and between groups in a pile system. Possibility of block failure mode in a pile group is also considered. Model error analysis of group capacities is evaluated based on full-size group tests.

The levels of risk implied by the current methods for predicting axial capacity of a friction pile are evaluated for both onshore and offshore sites. Procedures for determining appropriate probability - based factors for pile design are demonstrated, reflecting the level of the uncertainties involved and the desired level of design safety. The procedure is also extended to the case of pile group/system by taking into account group effect, correlation between individual pile capacities, and also the reserve strengths offered by inner piles in a typical pile system.

Methods are developed to update the systematic pile capacity model error for a specific site based on results of in situ pile tests and/or pile driving information. In the case of multiple pile test at a given site, correlation between individual pile test results is included in the formulation. Error arising from load measurement is also considered. (Abstract shortened with permission of author.)

Order No: AAC 8707442 ProQuest - Dissertation Abstracts

Title: PRESSUREMETER METHOD FOR SINGLE PILES SUBJECTED TO CYCLIC LATERAL LOADS IN OVERCONSOLIDATED CLAY

Author: MAKARIM, CHAIDIR ANWAR

School: TEXAS A&M UNIVERSITY (0803) Degree: PHD Date: 1986

pp: 332

Source: DAI-B 47/12, p. 4991, Jun 1987

Subject: ENGINEERING, CIVIL (0543)

Abstract: The pressuremeter method for single piles subjected to monotonic loading was extended to the case of cyclic loading by taking into account the degradation of the soil stiffness as a function of the number of loading cycles.

First, seventeen cyclic pressuremeter tests, using three different insertion methods (prebored, driven and pushed) were performed at the University of Houston pile load test site where two single driven piles (10.75 in. and 48.00 in. in diameter) had been previously subjected to cyclic lateral loading.

Two shear modulus degradation models were used: (1) G(,s)(N)/G(,s)(1) = N('-a) and (2) G(,s)(N)/G(,s)(1) = (alpha) e('((rho)/N)('(beta))), related to the permanent deformation model, (epsilon)(,a) = (epsilon)(,o) e('-((rho)/N)('(beta))), where G(,s) = soil shear modulus, N = number of cycles, (alpha), (beta), a = cyclic degradation parameters, (alpha), (epsilon)(,o) = limiting value of G(,s)(N)/G(,s)(1) and permanent deformation, respectively. These models were applied directly to the pressuremeter data, to obtain the cyclic soil properties.

The pressuremeter test results were used first to produce the monotonic P-y curves at different depth along the pile length. These P-y curves were used in a finite difference computer program to predict the monotonic response of the piles. The results show that all pressuremeters gave very satisfactory predictions. The driven pressuremeter predicted the response of both piles the closest. The pushed and the preboring pressuremeters slightly underpredicted the displacements.

The cyclic P-y curves were obtained from the monotonic P-y curves by replacing P by P x N('-a) where N is the number of cycles and a is the degradation exponent obtained from the analysis of the corresponding pressuremeter test. These cyclic P-y curves were used to predict the cyclic response of the two piles. Again, the results show that all pressuremeters give satisfactory predictions of the cyclic degradation\; the driven pressuremeter, however, gave the best predictions.

In addition a survey was made of pile load tests in clay where the pile had been subjected to stress control cyclic lateral loads. The degradation exponent a was backcalculated from those tests and it was found that a varied from 0.01 to 0.37 and averaged 0.12.

Order No: AAC 8508456 ProQuest - Dissertation Abstracts

Title: A SIMPLE STRAIN-SPACE PLASTICITY MODEL FOR CLAYS (CONSTITUTIVE, SOIL, PILES)

Author: CHELVAKUMAR, KASIVISVANATHAN

School: CALIFORNIA INSTITUTE OF TECHNOLOGY (0037) Degree: PHD

Date: 1985 pp: 195

Source: DAI-B 46/02, p. 615, Aug 1985

Subject: ENGINEERING, MECHANICAL (0548)

Abstract: This thesis develops and demonstrates a simple strain-space constitutive model for wet clays. It has been seen that a strain-space formulation of the constitutive behavior of engineering materials facilitates the solution of boundary value problems involving these materials. Soil, because of its multi-phase granular constitution poses challenging problems in constitutive modeling. Although several stress-space plasticity models exist for soils, they are not used commonly in engineering practice due to their complexity. It is attempted herein to develop and test a simple model which could result in simplified solutions for some soil problems.

The model is based on the experimentally observed physical behavior of soil. Certain approaches alien to conventional plasticity are employed so that the material behavior is closely predicted without sacrificing the simplicity of the model.

The model is initially developed for triaxial load systems. Its predictions are then tested against other model predictions and experimental data. The model is then generalized. The generalization renders the model capable of handling general stress-strain states and finite deformations.

Finally, the generalized model is used to solve an idealization of a practical problem. The problem of a pile driven into a soil medium is idealized as an expanding cavity in a homogeneous infinite medium. The solution predicted by the strain-space model is compared with other model predictions and test results.

Order No: AAC 8510336 ProQuest - Dissertation Abstracts

Title: LARGE DEFORMATION ANALYSIS OF PENETRATION PROBLEMS INVOLVING PILES AND SAMPLING TUBES IN SOILS

Author: KARIM, USAMA FARHAN

School: STATE UNIVERSITY OF NEW YORK AT BUFFALO (0656)

Degree: PHD Date: 1985 pp: 177

Source: DAI-B 46/03, p. 941, Sep 1985

Subject: GEOTECHNOLOGY (0428)

Abstract: It has been realized that the insertion of a rigid object into the ground, such as a driven pile or a sampling tube, produces significant distortion and modifications to the states of stress in the surrounding soil. As a consequence, for a state dependent material such as soil, its mechanical properties and any subsequent behavior is bound to be affected.

Any realistic analysis to this problem has to consider the interactive nature of the deforming soil and the penetrating body from the onset of insertion, by allowing the soil to gradually displace in order to accommodate the inserted object until it is fully installed. By taking into account the existing soil state, and the large geometrical changes occuring during installation, one can trace the complete load deformation history. The modifications to the effective stresses and the degree of disturbance for any region of interest, be it a foundation structure close to the driven pile or the material inside a sampling cylinder.

The complex nature of these non-linear problems had led many researchers adapting simplifying procedures leading to gross errors and misinterpretation of the results. Developments in pile-driving had tended either to separate the process of installation and its effects from subsequent behavior or ignored it completely. In the case of sampling no one had so far been able to qualitatively assess the resulting degree of disturbance on the soil parameters measured.

It is the lack of guidance in this important field, and the need for a realistic and consistent approach to the analysis of these problems which had led to this research. For this purpose, Finite Element formulation based on an updated Lagrangian approach, had been developed to investigate a class of penetration problems in geotechnical engineering. Such a formulation is capable of dealing with a variety of field situations in which the non-linear nature of the behavior of soil and large geometric distortions are considered. The effective stress analysis developed here is based on an elasto-plastic critical state soil model and large displacements theory and couples the deformation and pore water pressure formation and dissipation during loading.

Order No: AAC 8501879 ProQuest - Dissertation Abstracts

Title: STIFFENING EFFECT OF DRIVEN SHALLOW PILES IN A SEMI-INFINITE SOLID

Author: NASUTION, AMRINSJAH

School: UNIVERSITY OF MINNESOTA (0130) Degree: PHD Date: 1984

pp: 122

Source: DAI-B 45/11, p. 3574, May 1985

Subject: ENGINEERING, CIVIL (0543)

Abstract: When a relatively rigid footing or pavement placed on a well-drained subgrade is loaded, it experiences a downward deflection.

The ratio of the load to the displacement, referred to as the stiffness of the subgrade, has an important bearing on acceptable structural performance. This stiffness can be increased by driving shallow piles beneath the footing or pavement. Ideally, the vertical displacement due to the load imposed can be greatly reduced at the pile location.

An approach to determine the surface deflection due to combined effect of the surface loading and a single pile resistance is effected by idealizing the pile as a one-dimensional elastic continuum embedded in, and continuously bonded to, a three-dimensional elastic solid.

An analytic technique for evaluating stresses and deformation in a semi-infinite solid under sub-surface loading is developed.

Order No: AAC 8217326 ProQuest - Dissertation Abstracts

Title: ANALYSIS OF A DOG-LEG PILE

Author: GUIDO, VITO ANGELO

School: POLYTECHNIC UNIVERSITY (0179) Degree: PHD Date: 1982

pp: 415

Source: DAI-B 43/03, p. 806, Sep 1982

Subject: ENGINEERING, CIVIL (0543)

Abstract: The use of piles as a possible foundation alternate is not uncommon. Damage to the piles during the driving sequence, especially the bending of the piles, is of major concern to the design engineer. This bending can take two forms, a sharp bend or a continuous bend. With a sharp bend the pile undergoes an abrupt angle change at some point along its length\; the pile is composed of two more or less linear segments. This type of pile is frequently referred to in the construction trade as a dog-leg pile. A pile which has a continuous bend does not have a single angle change but a continuous curve of some form. This dissertation is confined to the analysis of a dog-leg pile.

Analytical investigations of the effect of the bending of the pile, on its ultimate load carrying capacity and subsequent settlements, have been confined to the use of the horizontal subgrade modulus. This approach has been abandoned, since the horizontal subgrade modulus is not readily available. This is not to say that empirical relationships are not available, but that they are so numerous and yield such varied results that for all practical purposes they are inadequate.

The method utilized is elastic in principle. H. G. Poulos (University of Sydney, Australia) has written extensively on the load-settlement characteristics of vertical and battered piles, subjected to axial and/or lateral loadings, employing linear elastic theory. The basic premise to Poulos' solutions, is that anywhere along the pile the displacements of the soil, adjacent to the pile, and the pile itself must be compatible at a given point. Consideration of both radial and vertical displacement compatibility does not significantly alter the results for vertical compatibility only\; therefore, Poulos considers only vertical displacement compatibility in his solutions.

This dissertation extends Poulos' concepts to the dog-leg pile problem. Use of only vertical displacement compatibility, of the soil and pile, was also utilized for the dog-leg pile, on both the vertical and inclined sections. A system of radial stresses develop on the pile circumference, as a result of the bend, in addition to the shear stresses. Superposition of these two loading mechanisms yields the desired vertical soil displacements. The solution to the dog-leg pile problem is mathematically intractable without the utilization of a computer, resulting in a complex computer program. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of school.) UMI

Order No: AAC 8309134 ProQuest - Dissertation Abstracts

Title: DEVELOPMENT OF CORRELATIONS TO IMPROVE THE PREDICTION OF AXIAL PILE CAPACITY

Author: DENNIS, NORMAN DALE, JR.

School: THE UNIVERSITY OF TEXAS AT AUSTIN (0227) Degree: PHD

Date: 1982 pp: 352

Source: DAI-B 43/12, p. 4077, Jun 1983

Subject: ENGINEERING, CIVIL (0543)

Abstract: Prediction of axial pile capacity presents a difficult problem to engineers. Most design methods in use today are based on correlations between soil properties and pile capacity. Many of the correlations were developed from a small data base and their applicability to larger populations is not always appropriate.

To illustrate the effectiveness of the existing design methods 1004 pile load tests, representing pile/soil conditions in 15 foreign countries and 35 states, were used to evaluate eleven of those in most common use.

When these methods were employed with uncorrected soil strengths in homogeneous deposits of sand or clay the average of the predictions for a given method was within a factor of error of 1.5. However, the scatter in measured (Q(,m)) vs. predicted (Q(,c)) capacity, as measured by the standard deviation of Q(,c)/Q(,m), was large. In most cases the problem was amplified when piles in interstratified deposits of sand and clay were evaluated. Factors of error ranged up to 13 for individual tests with some methods. Factors found to exert a significant influence on the ratio of Q(,c)/Q(,m) were, the method of determining soil strength, pile length, and the driving and loading history of the pile.

Through a series of direct comparisons and indirect correlations, empirical coefficients and correction factors were developed to modify several of the predictive methods in both sand and clay. In cohesive soils, revised pile/soil adhesion factors ((alpha),(lamda)), correction factors for soil strength, and corrections to account for near surface effects, were found to be most important. In cohesionless soils, revised correlations between penetrometer tests and pile capacity were developed, along with new guidelines for assigning unit side friction and end bearing factors, based on visual soil classification.

Analyses conducted on common data sets for sands and clays indicated the modified design methods provided superior accuracy over unmodified methods. Average values of Q(,c)/Q(,m) for the modified methods were near one and the scatter in prediction was reduced by as much as 80% in some cases.

Order No: NOT AVAILABLE FROM UMI ProQuest - Dissertation Abstracts

Title: NON-LINEAR CONSOLIDATION AROUND DRIVEN PILES IN CLAYS.

Author: KAVVADAS, MICHAEL

School: MASSACHUSETTS INSTITUTE OF TECHNOLOGY (0753) Degree: SCD

Date: 1982

Source: ADD X1982

Subject: GEOTECHNOLOGY (0428)

Order No: AAC 8270054 ProQuest - Dissertation Abstracts

Title: THE DEVELOPMENT OF SHAFT FRICTION IN SEMI-FULLSCALE PILES PASSING THROUGH GRANULAR SOILS

Author: KAY, WILLIAM FREDERICK, JR.

School: POLYTECHNIC OF WALES (UNITED KINGDOM) (0811) Degree: PHD

Date: 1981 pp: 342

Source: DAI-B 43/07, p. 2281, Jan 1983

Subject: ENGINEERING, CIVIL (0543)

Abstract: The present study examines the load transfer mechanism and subsequent soil displacements around a 0.114m diameter pile passing through a sand stratum.

The available literature on deep foundations is reviewed. It was found that the amount of literature pertaining to pile behaviour in layered soils, was limited.

A model pilot study showed that the most efficient means of eliminating end bearing, while simulating an underlying clay stratum, was by driving the base of the pile into a frictionless cylinder.

The composite test pile incorporated load cells for the measurement of the load distribution. The sensitivity of the initial 'Shell' type cell was found to be insufficient at the smaller loads which were developed near the pile base. Subsequently, the more sensitive 'Core' type cell was designed and proved satisfactory.

The test pile was loaded in a 3m diameter by 3m deep concrete testing tank equipped with sand placement machinery and a dust extraction unit. Small plates, linked to transducers, were used to measure the sand displacements around the pile.

A small dynamic probe was used to monitor the uniformity of placement and degree of compaction of each sand layer.

A series of loading tests was carried out in loosely placed and compacted sand layers.

The test data was recorded on punched tape. Processing and plotting of the test results was accomplished using the facilities of the DECsystem-20 computer. The results showed: (1) the stress transfer curves were similar to those proposed by Vesic, in sand, and those obtained by Meyerhof and Sastry in layered soils. No skin friction was developed at the top or the bottom of the sand, (2) the vertical sand displacement decreased with increasing depth, radial distance, and sand density, (3) the CRP, MLT, and pull-out tests showed that the skin friction was dependent on the direction and sequence of testing, (4) an expression for the coefficient of earth pressure Ks along the pile shaft was determined, based on the experimental data. The values of Ks were found to increase with increasing density and to decrease with embedded length.

Order No: AAC 8117697 ProQuest - Dissertation Abstracts

Title: SOIL SET-UP DUE TO PILE DRIVING

Author: AYOUB, WAFIC TAWFIC

School: TULANE UNIVERSITY, SCHOOL OF ENGINEERING (0494)

Degree: DENG Date: 1981 pp: 480

Source: DAI-B 42/03, p. 1105, Sep 1981

Subject: ENGINEERING, CIVIL (0543)

Abstract: Until recently, predicting the increase in soil resistance during pile driving due to short or lengthy delays was unfeasible. It has often relied on experience and judgement.

Estimating the hammer efficiency for theoretical wave equation studies was disputable. Dynamic measurements performed on piles during pile driving produced a wide varying range of unexplainable efficiency correlations.

From fifteen actual platform case studies comprising over eighty piles, design curves to estimate the average increase in unit friction and the ratio of average increase in unit skin friction to average unit adhesion at the resumption of pile driving as a function of time and depth are provided.

A new concept that explains the variation in dynamic measurement results is also provided.

A new theoretical method to construct the soil resistance during pile driving versus blows/foot curve is included.

It is hoped that the work included in this study will be an incentive for further research work.

Order No: AAC 7918713 ProQuest - Dissertation Abstracts

Title: PILE DRIVING ANALYSIS OF LARGE DIAMETER HIGH CAPACITY OFFSHORE PIPE PILES.

Author: ROUSSEL, HERBERT JOSEPH, JR.

School: TULANE UNIVERSITY, SCHOOL OF ENGINEERING (0494)

Degree: DENG Date: 1979 pp: 230

Source: DAI-B 40/02, p. 856, Aug 1979

Subject: ENGINEERING, CIVIL (0543)\; ENERGY (0791)

Order No: AAC 7606919 ProQuest - Dissertation Abstracts

Title: MECHANICS OF DIESEL PILE DRIVING.

Author: REMPE, DAVID MAHER

School: UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN (0090)

Degree: PHD Date: 1975 pp: 261

Source: DAI-B 36/09, p. 4614, Mar 1976

Subject: ENGINEERING, CIVIL (0543)

Order No: AAC 1307897 ProQuest - Dissertation Abstracts

Title: A STUDY OF THE EFFECTS OF PILE DRIVING VIBRATIONS ON NEARBY STRUCTURES.

Author: HECKMAN, WILLIAM STEVEN

School: UNIVERSITY OF LOUISVILLE (0110) Degree: MS Date: 1975

pp: 104

Source: MAI 14/01, p. 17, Spring 1976

Subject: ENGINEERING, CIVIL (0543)

Order No: AAC 7013333 ProQuest - Dissertation Abstracts

Title: SOME HEAVE PHENOMENA ASSOCIATED WITH PILE DRIVING

Author: HAGERTY, DONALD JOSEPH

School: UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN (0090)

Degree: PHD Date: 1969 pp: 325

Source: DAI-B 31/02, p. 665, Aug 1970

Subject: ENGINEERING, CIVIL (0543)

Order No: AAC 6915816 ProQuest - Dissertation Abstracts

Title: SOIL RESISTANCE TO VIBRATORY PILE DRIVING

Author: GUYTON, WILLIAM LOUIS

School: THE UNIVERSITY OF TEXAS AT AUSTIN (0227) Degree: PHD

Date: 1969 pp: 179

Source: DAI-B 30/04, p. 1671, Oct 1969

Subject: ENGINEERING, CIVIL (0543)

Order No: AAC 6808929 ProQuest - Dissertation Abstracts

Title: VIBRATORY PILE DRIVING ULTIMATE PENETRATION AND BEARING CAPACITY

Author: GHAHRAMANI, ARSALAN

School: PRINCETON UNIVERSITY (0181) Degree: PHD Date: 1967

pp: 144

Source: DAI-B 28/12, p. 5002, Jun 1968

Subject: ENGINEERING, CIVIL (0543)

Order No: AAC 6707307 ProQuest - Dissertation Abstracts

Title: A CRITICAL EVALUATION OF SOME PILE DRIVING FORMULAS

Author: VARMA, MAHESH

School: OKLAHOMA STATE UNIVERSITY (0664) Degree: PHD Date: 1966

pp: 97

Source: DAI-B 27/12, p. 4387, Jun 1967

Subject: ENGINEERING, CIVIL (0543)

Order No: AAC 6705727 ProQuest - Dissertation Abstracts

Title: FRICTIONAL RESISTANCE IN VIBRATORY PILE DRIVING

Author: HILL, HOWARD THIEBAUT

School: PRINCETON UNIVERSITY (0181) Degree: PHD Date: 1966

pp: 133

Source: DAI-B 27/11, p. 3925, May 1967

Subject: ENGINEERING, CIVIL (0543)

Driven Pile Manual Volume 1a
Driven Pile Manual 1b
Driven Pile Manual 2