Search Documents

By Alan B. Wagner

Data from seven instrumented pile load tests in Milwaukee, Wisconsin and two other instrumented load tests reported in the literature, one in Evanston, Illinois and one in Houston, Texas were reviewed. The data were for pipe piles having diameters from 9-5/8 inches to 18 inches, driven to depths between 36 and 96 feet. These data were used to develop a relationship between effective vertical stress and unit side friction and unit end bearing. These relationships were based on readily measured soil parameters, undrained shear strength, Cu, and Standard Penetration Test (SPT) values. This Beta (ß) and Nt approach and four other methods were then used to calculate the bearing capacity of the nine cases analyzed. The results from each of the methods are compared with the measured results.

Jan 1, 1991

By Xu Ronglie

This paper looks back on the developments and achievements of deep foundations, on the basis of the complex geological conditions and environments in China. It sums up advances in theoretical and applied researches, engineering constructions, practical experiences, case histories, and problems and developing prospects of piles and deep foundations in recent years in China.

Jan 1, 1991

"1 INTRODUCTIONThe use of nondestructive testing (NDT) methods to evaluate the integrity of Augered Cast-in-Place (ACIP) and Drilled Displacement (DD) piles has been a subject of significant debate among engineers, contractors and NDT practitioners. This guideline document will illustrate the importance of reviewing all available information in conjunction with the NDT records. ACIP and DD piles have unique properties that must be considered when using a specific NDT method. Any evaluation of the integrity of an ACIP or DD pile must also include a thorough review of the detailed pile installation records and the site specific soil conditions. Long or theoretical descriptions of the methods have not been included in this publication. More detailed information about these NDT methods including their theoretical and historical backgrounds can be found in DFI’s Manual for Non Destructive Testing and Evaluation of Drilled Shafts (2004). Additional information can also be found in the more comprehensive textbook Nondestructive Testing of Deep Foundations by Hertlein and Davis (2006).1.1 PurposeThe intent of this guideline is to provide practical guidance for the proper interpretation of NDT results on ACIP and DD piles. Short descriptions of the main integrity methods available are provided along with several examples of how to use all of the information available to make sound engineering judgments about the results. This publication is a state-of-the-practice guideline to promote accurate engineering evaluations.For engineers inexperienced with NDT, these guidelines provide sufficient background information on NDT methods to help understand the limitations of the testing, assess the results presented to them, and formulate appropriate questions. This is particularly important for engineers charged with the responsibility to determine from those results what, if any, consequences there may be on the performance of the structure under construction."

Jan 1, 2016

By Wen Songlin

This paper presents an experimental program to investigate the behavior of a pile with wings under horizontal loads in sand at laboratory. The work focused on evaluating the lateral resistance behavior and the geometric effect of wing board on the horizontal resistance. Based on the measured data and observed phenomenon, the following behaviors have been observed: 1) A pile with wings is not only a powerful means to improve the horizontal bearing capacity of a pile foundation but also economy and feasibility; 2) The horizontal bearing capacity of a pile with wings increases with increasing of it?s wing board?s area; 3) The pile lateral capacity is also influenced by the wing board?s geometric shape. Under a certain soil and pile condition, there is a critical embedment depth of the wing board, which will yield the maximum horizontal bearing capacity. It was further observed that when the displacement of the pile head increases, part of the horizontal bearing capacity of the pile is developed by the so-called shaft?s anti-pulling capacity.

Jan 1, 2007

By Robb L. Swenson

Construction of foundations for the Skyway Segment of the San Francisco Oakland Bay Bridge required innovative techniques due to the mass of the structures being inserted and the unique subsurface of the Bay. Twenty of the pier structures required large sheet pile cofferdams. Eight other foundations were installed in open water without cofferdams at the deeper part of the Bay. This narrative will present the initial planning, as well as the stages of installation, for each type of foundation. The first section will discuss foundation constructability modifications made during the initial planning phases of the project. Considerable effort was expended by Caltrans, the owner, T.Y. Lin the designer, and KFM (Kiewit/FCI/Manson) the contractor in modifying the design to assure that required tolerance would be maintained during the installation of the foundations. The final section will describe the steps required for installation including: initial access dredging, installation of cofferdams, preparation required to install the footing boxes, footing box installation, foundation support pile installation, and pile to box connections.

Jan 1, 2005

By Gandhi

Piled raft foundation under uniformly distributed vertical loads has been analyzed using Finite Element Method. The soil is considered to be linear elastic, isotropic, homogeneous. The raft,pile and the soil have been idealized with eight noded brick elements. Parametric study have been carried out varying pile length, soil modulus, raft thickness, and pile spacing. Design charts have been produced to achieve 50% load sharing between pile and raft for optimum design. Data available in literature is compared with the design chart results and found satisfactory.

Jan 1, 1996

By Cassandra A. Wetzel

Rock socketed mini-piles are a desirable foundation alternative when design capacity is more than 40 tons and there is limited access. In this case history mini-piles were designed to support between 75 and 200 kips at 12 locations adjacent to a perimeter wall, a party wall and at cast iron column piers. Limited geotechnical information, low overhead clearance, and active building population tested the creativity of the team to get the piles installed. The key geotechnical concern during installation of the mini-piles was the presence of a glacial till layer above the bedrock surface that restricted the seating of the casing into bedrock with a track mounted drill rig. Soil loss during the advancement of the rock socket using an air hammer was excessive and increased the risk of subsidence. Over a three week period the engineer worked with the contractor to modify the design, means, methods, and materials to install piles with adequate load capacity. This paper will present the changes in design and construction methods that were required.

By Peng Jiahong

With ultrasonics application during checking the large diameter cast-in-situ pile body, it is usualy applied the statistical method of probability and PSD. This paper presents a converse probabilistic-analytical method which can identify important anomalies, both strong and weak, during interfered situation. So the inhomogeneity in concrete pile may be ellectively distinguished. In order to ensure the capacity of bed rock support layer under large diameter pile, a test-in-situ is conducted to determine the compresive strength and shear force inserting rock of the support layer, so the compresive strength and modulus value of elasticity of bed rock tested will closely tally with the actual situation.

Jan 1, 1991

By Emad Farouz

The resistance of very dense glacial outwash formations consisting of sand, gravel and cobble formations can be quite high, and techniques for measuring the strength and deformation properties often cause engineers to underestimate the strength of these layers in drilled shaft design. More realistic measurements of this dense formation can be achieved with slotted steel casing pressuremeter tests. To minimize disturbance and achieve accurate measurements, drilling a pilot hole prior to probe insertion is necessary. Characterizing geologic formations that contain significant amounts of gravel and cobbles is challenging because of scale factor. Inserting a standard pressuremeter probe into this formation without damaging the membrane is difficult. This paper presents a case study for the IR-75 project in Dayton, Ohio, USA, where these dense materials were characterized using a slotted casing pressuremeter, optimizing design by providing more realistic properties of these materials.

Jan 1, 2006

By Patrick P. A. Wolfs

In the summer of 2000, the ECR®/EFT® was first introduced in the Netherlands. After the first project a field test was performed together with other geophysical methods to prove the liability of these systems and their application in areas with soft soil and high groundwater levels. The objective of this test, which was carried out with three leakage detection systems, was to locate the holes. After this test several projects have been carried out. In this article the Dutch projects "Ringvaart Aqueduct" and "Bottleneck Limburg N296/N297" are mentioned.

Jan 1, 2006

By R. H. Wright

This paper describes the design philosophy and methods employed in constructing the foundation elements for the Little Britain Project in the City of London. The Contract is a design and construct package for the foundations of a 3-storey basement which will be built using "top-down" construction techniques and is to be carried out by Fairclough Piling and Marine on behalf of Wimgrove Nominees. The Project includes 8000 sq.m. of diaphragm wall and barrettes 139 No. large diameter piles ranging from 900mm to 3000mm in diameter and up to 45m deep, and 9 No. cruciform barrettes for the heaviest column loads. Major factors influencing the design of these foundations include differential settlement, heave analysis and a fast track construction approach. Little Britain will provide 43000 sq.m. of space in two linked buildings which will bridge a new road joining London Wall to Newgate Street. The foundation contract is well advanced and the building is due for completion in the Summer of 1990.

Jan 1, 1989

By I. Stanculescu

The consolidation of thick and very compressible soil deposits by stone columns associated with cast-in-place plain concrete columns, has been performed for shallow foundations of some heavy industrial structures. The reduction of settlements and increase of soil bearing capacity were thus ensured as a result of soft soil interaction with stone and concrete columns. The results of model tests and in situ large scale applications are presented. A calculation procedure is also suggested for foundation bases improved by the proposed method.

Jan 1, 2010

By Noreen Tarac, Pablo Forgoso, Philipp Schober

A multiple use storage facility building is being developed in the Philippines on a peninsula that was reclaimed in the 1990s without any soil treatment. The subsoil now consists of loose to medium dense silty sand underlain by a soft to medium stiff clay. A liquefaction assessment by analytical methods have shown that the loose to medium dense silty sand yields a high potential for liquefaction and lateral spreading during pthe design level seismic event. To mitigate the risk of liquefaction and lateral spreading, as well as assure the slope stability of the shoreline, a solution utilizing a combination of ground improvement techniques by means of a Mixed-In-Place (MIPTM) Lattice Grid Wall and Stone Columns was developed and successfully executed. For the detailed seismic design, a Finite Element 3D analysis was undertaken to simulate static and dynamic actions on the buttress wall. The liquefaction assessment and settlement calculation were carried out based on analytical design approaches. For the execution of the Lattice Grid Wall, the Mixed-In-Place (MIPTM) method developed by BAUER Spezialtiefbau GmbH was applied. The stone columns were installed using the Wet Top Feed method.

Sep 8, 2021

By Timothy C. Siegel

A piled raft refers to a shallow foundation that is structurally connected to the piles, while composite ground refers to a soil-pile matrix where the piles are not structurally connected. The design objectives for both a piled raft and composite ground are (excluding special considerations such as expansive soil): (1) to provide a sufficient ultimate resistance and (2) to distribute the load into the soil-pile matrix so that the settlement experienced by the shallow foundation is within tolerable limits. A simplified model is proposed for a shallow foundation on composite ground where the foundation settlement is estimated as the sum of the downward movement of the piles plus the downward movement of the shallow foundation relative to the pile head. The proposed simplified model is applied using conventional geotechnical analyses for two hypothetical examples of shallow foundations undergoing compression settlement.

Jan 1, 2011

By Jon Huff, Jeffrey Donville, Hannah Iezzoni, Dan Stevenson

Occasionally, in the design of deep foundations for a structure, a single deep foundation element may be used to support a building column. The most common type of element used in such cases is a drilled shaft (also referred to as a drilled pier, caisson, or bored pile). However, as installation capabilities have improved, large diameter augercast piles are increasingly more common. While drilled shafts and augercast piles differ significantly in construction methods, in the eyes of the International Building Code (IBC), both are treated as cast-in-place deep foundations and must comply with many of the same code provisions. Deep foundations are required to be braced such that lateral stability is provided in all directions, however isolated, cast-in-place elements that have a diameter (D) of at least 2-feet and a length (L) not more than 12 times the diameter can be an exception. In response to the concerns raised by some member professionals, the Deep Foundations Institute’s (DFI) Augered Cast-in-Place Pile and Drilled Displacement Pile Committee took a closer look at the code and its applications, the historical development of the code language through the years and performed analytical modeling to evaluate the impact of this ratio on a pile’s stability. The question is whether the limiting ratio included in the IBC 2018 code provisions is justified, or whether different criteria should be used to determine when isolated deep foundation members are allowed.

Sep 8, 2021

By Mark R. Svinkin

Construction-induced vibrations may be detrimental to adjacent structures and sensitive electronics operating nearby. Construction vibration sources have a wide range of energy and velocity, as a function of time, transmitted on the ground. Analysis of existing methods for predicting ground and structure vibrations shows that empirical equations provide calculations only of amplitudes of vertical soil vibrations with insufficient accuracy. This paper presents the application of the impulse response function concept to solve the geotechnical problem of predicting ground and structure vibrations before installation of vibration sources. Impulse response functions reflect real behavior of soil and structures without the investigation of soil and structure properties. A procedure is presented to compute predicted ground and structure vibrations. Good agreement is found between predicted and measured records.

Jan 1, 1999

By Mark X. Haley

Foundation design and construction in Boston has changed dramatically during the past 10 years. Prior to 1985, the primary foundation element in Boston, where deep foundations are required, was driven end-bearing piles. Since 1985, drilled or excavated high capacity foundation elements have been utilized more frequently. This paper will provide a historic perspective of their use and a summary of design parameters for elements installed and founded in the bedrock. TOPOGRAPHY Boston was founded in 1630 by the Massachusetts Bay Company of John Winthrop and his hearty band of Puritans. The settlement was chosen for: ? its safe harbor, ? abundant source of fresh water, and ? peninsula setting offering protection of the ocean on almost all sides with high ground for fortification. These three factors were a direct result of past geologic processes that created the Boston Basin by erosion of the soft bedrock underlying this area as compared to the harder granite rock to the north, west and south. As the glacial ice sheets melted and moved northward, various soil types were deposited. During ice sheet re-advancement the hills and islands of Boston took on their precolonial shapes. The Trimont, consisting of Beacon, Mt. Vernon and Pemberton Hill, rose to 150 ft above sea level with the smaller Copps and Fort Hill to the north and south.

Jan 1, 1994

By Zhitao Ma

The Cast-in-place Concrete thin-wall Pipe pile, referred to as PCC pile, is a new kind of pile for soft ground improvement. In this paper, firstly, the general introductions of the new pile technique, mainly including the technique principle, the structure of pile-driving machine, and the technological process were given, then based on the results of in-situ static lateral loading test, the pile lateral capacity, the relationship of load-deflection of pile at the ground surface, the lateral deflections versus depth and the soil reaction along the pile shaft were analyzed.

Jan 1, 2006

By B. M. Das

Several laboratory model test results for the determination of the ultimate uplift capacity of single and group metal piles embedded in near-saturated clay have been presented. Based on the uplift test results for single piles, the variation of the adhesion factor with the undrained shear strength of clay has been determined, and an empirical correlation for estimation of the adhesion factor in soft and medium clays has been presented. The group efficiency of piles under uplifting load depends on factors such as embedment ratio, undrained shear strength of clay, the number of piles in a group, and the center-to-center spacing of the piles.

Jan 1, 2010

By Ashutosh S. Dhar

Cast-in-place piles were examined in this paper from the viewpoints of construction quality, axial capacity, and load-displacement responses. The results of ten 450 mm diameter (18? f) bored piles, installed in a soil deposit of silt to medium dense sand using the method of percussion drilling, were tested under static loads. The results of the pile load tests were used for evaluation of various design methods of calculating pile capacity. The study revealed that the design methods based on the concept of critical depth underestimated the ultimate skin fiction. Thus, the applicability of the critical depth concept for design of bored piles under the soil condition considered may be unreliable. The estimated skin friction factor, ß, was too low in these methods. The Tomlinson method and the Neely method provided the best prediction of the ultimate skin friction. The methods used for calculating end bearing resistance were found to provide a conservative estimate of the resistance. During pile load tests, a settlement of 5 to 6 mm was required for full mobilization of skin friction for the piles in loose sand, while larger settlements (> 10 mm) were required for piles in denser soil. The ultimate skin frictional resistance was observed to be low for piles in loose sand.

Jan 1, 2006