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By Jon E. Bischoff

Construction of a secondary clarifier on the banks of Rainy River, Northern Minnesota, required the driving of H-piles 14HP102 to a sloping, very strong bedrock through thick deposits of soft and medium stiff soils. Pile toe protection, APF Hardbite HP 77750, was specified to prevent damage to the pile toe and to enable the pile toe to bite into the bedrock surface. The toe protection worked well for bedrock sloping less than 2H:1V. However, where the bedrock was steeper, the piles experienced damage and failed to reach bearing. In most cases, the also the replacement pile failed. Pile Driving Analyzer measurements showed that on encountering the bedrock, the pile toe reflection, which at first was sound, deteriorated indicating pile toe damage. Extraction for visual inspection showed that the failed piles were bent and had deformed pile shoes. In areas of steeply sloping bedrock and for replacement piles, an alternative shoe, the Scanpile Herkules rock shoe, was employed. This pile shoe proved to be able to secure the pile toe into the rock and to eliminate the problem. The costs of the Herkules rock shoe considering price, shipping, and attaching, were about equal with the Hardbite shoe.

Jan 1, 1993

By Greg Halsted, Joshua Gilman

Today's civil and geotechnical engineers play an important role in helping to achieve sustainable infrastructure. To address environmental sustainability and climate change caused by green- house gas (GHG) emissions, all engi- neers must adjust their traditional approach to materials, design and construction practices to include a focus on minimizing carbon dioxide emissions. The considerable influence that geotechnical engineers have on projects provides an important oppor- tunity to affect positive change. The carbon footprint of the construction methods and materials used for foun- dations can be as much as 8-9% of a new building's total carbon footprint, and geotechnical engineers have an op- portunity to evaluate alternatives based not only on cost, but also the long-term environmental impacts. Growing environmental considerations and societal concerns are influencing the selection of construction materials and methods, including cement and concrete's role and significance for infrastructure applications today and in the future.

Jan 1, 2023

By Scott M. Doehla

A proposed rehabilitation of a 200,000 sf, 75-foot high steel-frame building at the former U.S. Navy Yard in Brooklyn, New York required the review of existing foundation data and an investigation of the foundations with respect to their condition. The building was constructed in stages between 1856 and 1933, including several expansions and interior equipment with isolated foundations. The building has clear spans on the order of 50 feet and at one time supported cranes allowing transport of heavy equipment through the building. The proposed rehabilitation is to include a food manufacturing center and office space having multiple stories. Original construction drawings, available from the Brooklyn Navy Yard Development Corporation?s drawing archive, were reviewed to determine the foundation system supporting the structure. The original drawings provide a window into the methods utilized during late 19th and early 20th century pile foundation construction. The review revealed that the building is supported by pile foundations ranging from timber to concrete-filled steel pipe (depending on the year of construction). Annotations including pile driving records were available on some drawings indicating the design and as-built capacity (using the ENR formula for driving resistance). An investigation consisting of test borings was performed to identify the subsurface conditions underlying the building for evaluating theoretical capacity of the piles. A test pit investigation was performed against existing columns within the structure to expose the piles and pile caps for inspection pertaining to pile condition. The test pit investigation revealed methods utilized during original construction to integrate new columns with existing floor slabs, the use of below-grade brick arches to support a floor slab, and the condition of timber piles which were likely installed up to 120 years ago. The observations made within the test pits were compared with original drawings to evaluate the accuracy of these drawings.

Jan 1, 2008

By Ruth McKeown, Gilson de F. N. Gitirana, Murray Fredlund, HaiHua Lu

The current design standards for the use of anchors in slopes is based on two-dimensional (2D) limit equilibrium analyses. Anchors are considered as discrete loads and the 2D anchor, factored based on the spacing distance, corresponds to extending anchors indefinitely in the third dimension. A three-dimensional (3D) analysis offers a more realistic representation of the problem, including the true discrete nature of the anchor point loads. This paper explores the typical differences between analyzing anchors in 2D and 3D, using four typical conceptual models. Slopes with constant cross sections were shown to be adequately represented by the traditional 2D approach. The maximum difference between 2D and 3D models was 21% and becomes negligible for lower anchor spacing values, as expected. A slope with an external load was analyzed to evaluate critical slip surfaces with lower aspect ratios. Slip surfaces with lower aspect ratios presented higher edge effects that contributed to the stability of the slope. The results indicate that optimum design requires the 3D evaluation of field conditions inducing low aspect ratios, such as concave and convex surfaces, weak layers, and external loads. INTRODUCTION Slopes may be stabilized using a variety of solutions, including anchors. When performing an analysis, geotechnical engineers often follow the traditional two-dimensional (2D), Limit Equilibrium Method (LEM). It is important to understand the consequences and limitations of the assumptions on which the 2D LEM is based. There are numerous studies on anchors that show the importance of considering the actual three-dimensional field conditions. Desai et al. (1986) proposed a three-dimensional procedure based on the Finite Element Method and considering elastoplastic behavior and interface elements, to account for stress and displacement distributions, the relative motion between the anchors and the soil mass, and nonlinear soil behavior. Several important stabilization mechanisms were explained. The role of grout injection was evaluated in terms of the produced normal stresses along the anchor-soil bounding surface. The approach was shown to reproduce adequately experimental tests on a sand, proving realistic stress distributions around the anchor. Nonlinear soil behavior influenced to a large extend relative interface motions. Michalowski (1989) applied an upper-bound limit analysis in 3D to slope stability analyses. Anchors were not specifically considered in this study, but the consideration of locally loaded conditions shed light on important modeling aspects. The manner how the slide mechanism becomes three- dimensional as the slope is locally loaded was demonstrated. This emphasizes the fact that anchors should produce field conditions that require 3D analysis approaches.

Jan 1, 2019

By Don W. Dotson

In 1962, Kondner prepared several papers dealing with hyperbolic stress-strain response of cohesive soils. The following year, Brinch Hansen proposed 80% and 90% failure criteria for stress-strain behavior of cohesive soils. Fellenius was instrumental in popularizing these failure criteria for pile load tests and offered a direct solution equation for the failure load according to the 80% failure criterion. Since the 90% Criterion has been incorporated into the International Building Code, equations for the direct solution of the failure load at the 90% Criterion would be useful to practicing engineers. This Technical Note supplies the derivation methodology for the 80% Criterion and provides expressions to determine the load and deflection at failure for the 90% Criterion.

Aug 1, 2013

By P. D. Arumairaj, B. Vani

"Micropiles are small diameter cast insitu reinforced grouted piles and it has been effectively used in many applications of ground improvement. It increases the load carrying capacity of soil and reduces the settlement. It is also used in strengthening existing foundations. In this study, the effect of Solid and Hollow micropiles on the load carrying capacity of footing resting on sand is studied. The effects of solid Micropiles are investigated by conducting experimental model studies. The parameters involved in this study include the position of pile, pile length and pile spacing. Load test was carried out on a model footing resting on sand with solid and hollow micropiles. Load test trail is repeated for footing on Micropiles with varying lengths of 10, 20, and 30 times the diameter and spacing equal to 5, 4, 3, 2 times the diameter. The load-settlement behavior of each case is compared. Optimum length and optimum spacing of both the solid micropile and hollow micropile are determined. It is also observed that the effect of micropiles in the peripheral of footing resists lateral displacement of soil underneath the footing. The micropile beyond significant depth becomes redundant.INTRODUCTIONA micropile is a small diameter (less than 300 mm) drilled and grouted pile that is typically reinforced - FHWA-NHI 2005 (Federal Highway Administration-National Highway Institution). It is constructed by drilling a borehole, placing a steel reinforcing element into the borehole and grouting it. Hollow micropiles are typically reinforced by solid central bar that occupies about onethird of the hole volume. The grout is placed by gravity, under pressure methods or by a combination of both (post grouting). Thus, micropiles can be considered as small drilled-shafts that are specially drilled and grouted.Historically, micropiles have been introduced in Italy as a foundation system mainly for retrofitting and underpinning of structures that had sustained damage during World War II and access for conventional piling equipment was not possible (Bruce, 1988). The second generation of micropiles is a pressure grouted piles with a central mono all thread bar (with diameter up to 89 mm). They are installed by using either an open or cased hole drilling method.A new generation of micropiles, termed Grout injection bore micropiles (IBOR), was developed in the 1980s. The IBOR, currently named hollow bar micropiles, utilizes a continuous all-threaded hollow steel bar as the drilling and grouting conduit, which allows drilling and grouting simultaneously without the need of a casing during drilling. A sacrificial (lost) bit with openings that allow for pressure grouting of the hole is threaded onto the end of the hollow bar and is left in place following drilling. A drilling fluid (air, water, or grout) is introduced through the hollow bar and allows the spoils to flush from the borehole opening. Upon reaching the required depth, neat cement grout is then injected under high pressure into the drilled hole to fill the annulus between the bar and the soil from the bottom to the top. Due to the grouting method employed, the shape of the hollow bar micropile is expected to have a bulb shape with an enlarged base."

Jan 1, 2015

By Silas C. Nichols

FHWA Interest is due to: ? An increase in successful projects in the U.S. private sector and in other countries ? Cost effective and more efficient in many circumstances ? Agency Priorities - FHWA "Vital Few" AASHTO TIG

Jan 1, 2005

By Osvaldo Valdez, Matteo Bertoni, Aem Ragy

The East St. Louis Deep Cutoff Wall project is located in the area of East St. Louis, Illinois, across the Mississippi River from the city of St. Louis, Missouri, along the left descending bank of the river. The project is a fundamental part of the U.S. Army Corps of Engineers' (USACE) effort to rehabilitate and secure the aging East St. Louis levee system that provides flood protection to approxi- mately 250,000 residents and more than $4.5 billion in economic value. The project was devised and de- signed by USACE as a cutoff wall to be installed in the Metro East Sanitary District levee segment, one of the levee segments that form the East St. Louis system. The contract for the construc- tion of the cutoff wall was awarded in November 2019 to Bauer Foundation, the American subsidiary of the Bauer Group.

Sep 1, 2023

By Douglas L. Scaggs

Over the past several years, pile foundations have grown to meet the demands of larger and heavier structures. As the foundations have grown, so has the need for larger and more robust piles to carry the increased loads. Seismic considerations have also required larger and tougher piles to withstand the added component of supporting structures during earthquakes. While H-piles, precast concrete piles, timber piles and small pipe piles have been the product of choice, many applications are now calling for much larger piling requiring larger equipment and presenting the contractor with new challenges. This paper is not intended to be a ?how to? guide as much as a discussion on the potential pitfalls a contractor should watch out for when considering a project where mega piles are required.

Jan 1, 2013

By Jim Cook

Arsenal Football Club required the development of a new home stadium in north London, subsequently named the Emirates Stadium. The proposed development comprised a 60,000 seat stadium, with associated facilities and a sports training centre. Described are the foundation solutions and piling construction techniques used, which take into consideration the potential impacts on existing above and below ground railway infrastructure and underground water structures. Methods used by the piling contractor to improve aspects associated with health, safety and quality are also described.

Jan 1, 2008

By Lawrence F. Johnsen, Marc J. Gallagher

"Micropiles are small diameter, bored, grouted-in-place piles incorporating steel casing and/or reinforcements. The omission of micropiles from most United States building codes has resulted in the application of varying standards for design and installation. The ADSC/DFI Micropile Committee has developed a proposed section for the 2006 edition of the International Building Code (IBC 2006) covering micropiles. The proposed IBC 2006 micropile code section is presented, along with comparisons to existing micropile codes and guidelines. A discussion section is provided to clarify sections of the proposed code. IntroductionMicropiles, defined as small diameter (typically less than 12 inches outer diameter), bored, grouted-in-place piles incorporating steel casing and/or reinforcements, are becoming common foundation elements for new construction, retrofits, and emergency repairs. Developed in Europe in the 1950's and used in United States practice since the late 1970's, micropiles are typically not addressed in building codes, particularly in the United States. As a result, micropiles are often reviewed by building officials to a variety of standards, including drilled shafts, caissons, cast-in-place bored piles, and concrete filled pipe piles. None of these adequately address the unique design and construction aspects of micropiles. Therefore, it became apparent to the foundation design and construction community that a micropile-specific code section was required.To that end, the International Association of Foundation Drilling and the Deep Foundations Institute (ADSC/DFI) Micropile Committee appointed a subcommittee in October 2003 to develop and submit a proposed micropile code section for the 2006 IBC. The subcommittee members included the two co-authors, as well as Tom Richards (Nicholson Construction Company), Tom Armour (DBM Contractors, Inc.), John Wolosick (Hayward Baker, Inc.), Allen Cadden (Schnabel Engineering) and Matt Niermann (Schnabel Foundation Company). At the time of the writing of this paper, the proposed code section has been presented at the IBC public hearing during which it was modified slightly. Final adoption (or rejection) will be determined by the IBC at the final action hearing in September 2005. The attached code section is the revised version following the public review hearings."

Jan 1, 2005

By W. Morgan NeSmith

"The DFI ACIP Pile Committee, in conjunction with the Florida DOT, completed an ACIP Pile installation monitoring and performance test program in late 2016 to advance the inclusion of ACIP piles in future specifications for bridges by state agencies. Piles of different diameters were installed for compression, tension and lateral testing, and one pile was extracted for visual inspection. This paper presents the pile installation, non-destructive testing and load test results of the program.INTRODUCTION The Deep Foundations Institute (DFI) Augered Cast-In-Place (ACIP) Pile Committee performed a ACIP pile installation and test program in the fall of 2016 to demonstrate a fully monitored installation of 18-in and 24-in diameter ACIP piles. The program included automated and manual installation monitoring, Thermal Integrity Profiling, compression, tension and lateral load testing (including monitoring of strain gages embedded along the compression pile shaft), and post-testing extraction of an installed pile for visual inspection.PROJECT DETAILS AND FIELD EXPLORATION A general program location map along with an aerial view of the property in Okahumpka FL is shown in Figure 1. Two Cone Penetration Tests (CPT) were performed at initial reaction pile locations R-6 and R-8 (Figures 2 and 3) The results from CPT R-6 indicated very loose soil conditions at depths below 55-ft, indicating potential relic sinkhole conditions. The test layout was subsequently rotated and moved south of CPT R-8.TEST PILE INSTALLATION DETAILS Seven piles were installed to either 40-ft or 60-ft below grade. Thermal Integrity Profile (TIP) wires were installed in all piles but varied to include one wire each attached to a steel center bar or one wire attached to the steel center bar AND four additional wires (each) attached the steel reinforcing cage installed in these piles. Additionally, the 24-in lateral and compression piles had four steel or PVC casings installed next to the TIP wires for testing by thermal probe and/or wire inserted into the casing."

Jan 1, 2017

By Dimitrios C. Konstantakos

Cofferdam excavations have traditionally been designed with classical design methods that involve direct computations of active or apparent earth pressures. However in contrast to finite element methods, traditional analyses can not account for full soil-structure interaction. Because of their complexity, numerical analyses are performed almost exclusively by computers. Recent theoretical and computer advancements have made the use of the finite element method much more user-friendly and affordable. General information about the basics of the finite element method in geotechnical engineering and for cofferdam excavations is presented. While knowledge of all intricate theoretical and computational details is not needed, the designer should at a minimum be aware of the most important aspects of soil modeling. Most importantly, the designer must have sufficient experience to be able to judge the relative ?correctness? of vast numerical results produced by today?s software programs. Hence, the human factor is an irreplaceable component of finite element computations.

Jan 1, 2013

By G. L. Sivakumar Babu, P. Chaithra

"Raft foundations which are used against differential settlements and for carrying heavy loads can still be subjected to excessive settlements even if it is safe against bearing capacity consideration. Providing additional piles under the raft can reduce such settlements to acceptable values. In addition to settlements, the piles also relieve the raft a part of the total load and thus the bearing capacity of the Combined piled raft foundation (CPRF) is improved. Parametric study of response of piled raft foundation has been conducted and the results have been presented. The study is conducted using finite element based software, PLAXIS 2D. The main objective of the paper is to evaluate the parameters that affect the performance of piled raft for an economical and effective design. It has been shown that piled rafts are an economical solution in foundation design compared to raft foundation, for the soil conditions considered in the paper.1. INTRODUCTIONThe aim during the design and construction process of high-rise building foundations in urban areas is to ensure the lifelong safety and serviceability of the new and existing buildings in the neighborhood. In order to realize this aim in a cost-optimized manner, the combined pile raft foundation (CPRF) was developed (Katzenbach et al., 2005). For the foundation of high rise buildings with good subsoil, the simplest structure considered is a raft. But when the subsoil near the ground surface has low load-bearing capacity, high-rise structures are often rested on piled foundations.A piled raft and pile group serves similar purposes, but there are essential differences between them. A pile group is a set of piles that have a pile cap. The piles would be designed to share the pile load at ultimate state. The pile cap would be designed to link the piles together but the contribution of the pile cap to bearing capacity will not be included in the design. On the other hand, a piled raft is a foundation, wherein piles are provided along with the raft so that the total load acting is shared partly by the raft and partly by piles, rather than being dominated by the piles (as in a pile group). Piled raft foundations utilize pile support for control of settlements with piles providing most of the stiffness at serviceability loads, and the raft element providing additional capacity at ultimate loading (Poulos, et al., 2011). Therefore, piles are included in a foundation for two main design purposes: to provide adequate bearing capacity and to bring down the settlements to an acceptable level."

Jan 1, 2015

By Jeffrey R. Hill

This paper discusses the use of micropiles for the rehabilitation of the following two structures: the Milwaukee Auditorium Theatre, in Milwaukee, Wisconsin, and the Cupples Ballpark Lofts, in St. Louis, Missouri. The paper focuses on the similarities and differences of the remediation techniques used for each structure. The discussion highlights the method of attaching the micropiles to each respective structure. Generally the paper discusses the micropile installation at each project with supporting photos, figures and data. Load testing at each project is also discussed, including the comparison of load test results for each project. The paper will focus on the load testing program at the Milwaukee Auditorium Theatre where high capacity micropiles were designed and tested as friction piles founded in stiff clays and end bearing micropiles in dolomitic limestone. The results of the test were used to determine if the micropiles on the project would be installed as end bearing or friction bearing elements. Strain gauges were used in addition to conventional deflection vs. load data for the Milwaukee Auditorium Theatre project. Other aspects of the paper will include the differences in design methodology for end bearing micropiles in massive dolomitic limestone vs. design in softer, weathered limestone.

Jan 1, 2008

By X. M. Wu

The paper describes four different types of support for deep excavations, which are currently used in China. Local experiences were illustrated by presenting case histories for each type of support. For braced excavation in soft clays in Shanghai, the earth pressure against bracings were found to be in conformity with the trapizoidal estimation given by Terzaghi and Peck (1967). For tie-back support of excavations in Beijing and Shengyang, earth pressures were found to be much less than those predicted by ordinary rules. In the construction of a mining shaft in coarse sand below ground water level, high pressure jet grouting has been successfully used to form a circular impervious lining of the shaft. As an effective anti-slide measure, large diameter reinforced concrete piles constructed by open shaft method have been widely used with success.

Jan 1, 2010

By R. Chowdhury

The relevance of reliability studies for deep foundations is considered in this paper with special reference to pile foundations. Attention is drawn to uncertainties related to applied loads, the load-carrying capacity and the safety margin of a pile foundation. The essential steps in a reliability study are outlined. An essential goal of any study is the determination of the Reliability Index or Safety Index under different conditions of loading and operation. Calculations concerning probability of failure or success require an assumption to be made concerning the probability distribution of the safety margin. The significance of this and other assumptions should be clearly understood. Reliability approaches should be used to complement conventional deterministic studies.

Jan 1, 2010

By Donald A. Deardorff

The capacity of a helical pile can be determined analytically using the individual bearing or cylindrical shear methods which are dependent on soil strength parameters and helical bearing area. The torque correlation method is widely used in the helical industry to determine the capacity during installation by monitoring torque during the final seating of the helicals. This method has been shown to be a better predictor of strength than the individual bearing or cylindrical shear methods. To determine capacity using the torque correlation method, the final average installation torque (ft-lbs) is multiplied by an empirical torque correlation factor (Kt, ft-1). Kt values have been well documented for square bar shaft helical products and can vary from about 3 to 20 ft-1 depending on pile geometry and soil type. A default value of 10 ft-1 is generally used for all square shaft sizes and soil conditions. Less research has been done on determination of Kt for round pipe shaft helical products. Studies have indicated that factors which affect Kt include soil type/strength, number of helical plates, helix spacing, helix pitch, depth of embedment, downward pressure (crowd), shaft diameter (round pipe) and load application direction while other studies have discounted some of these factors as inconsequential. This paper reviews past research findings regarding Kt determination for square and round pipe shaft helical products and presents a case history of round shaft helical pile installations in Chicago clay which resulted in much lower than expected Kt values.

Jan 1, 2007

By Aditi Sharma, Sumanta Haldar

Scouring of soil is the major concern forthe various hydraulic structures built in the flowing rivers since scouring impacts the bearing capacity of foundations. Hence, consideration of scouring in the design of foundations for hydraulic structures is crucial. Pile groups in bridges are subjected to combined vertical and horizontal loading due to self-weight, live loads, vehicular impacts, wind load, earth pressure, and current. Hence, an assessment of the combined bearing capacity of pile groups subjected to scour is essential for the safety of the structure. This paper aims to analyze the bearing capacity of pile group supporting the bridge under combined loading i.e., Vertical (V) and Horizontal (H) loading subjected to local scour. Three-dimensional finite element model (3D-FEM) of a 3 x 3 pile group embedded in homogeneous sandy soil is established in Abaqus (2018). Mohr-Coulomb plasticity model is used for the soil domain. The pile group is modelled as linear elastic. Finally, V-H yield envelopes are obtained with and without scour. The potential impact of different parameters, such as angle of attack, flow velocity, depth of flow, and different pile length-to-diameter ratios (L/D) and spacing-to-diameter ratios (S/D) of pile group on V-H yield envelopes is studied.

Sep 1, 2022

By Julie Hampden, Tim Dardis, Per Reinhall

"Noise from impact pile driving can harm fish, marine mammals and other sensitive wildlife over large areas. Marine pile driving is highly regulated, and regulators require sound levels to be below certain thresholds to avoid harassment and injury to sensitive marine life. In many locations, timing restrictions, use of noise attenuation technologies and extensive monitoring for impacts to wildlife are also required. As a result, permitting can be laborious and time consuming, and project implementation and scheduling can be complicated. Underwater noise levels are measured with an underwater microphone (hydrophone), which converts noise pressure to voltage and is calibrated to express the noise pressure in Pascals (Pa). The pressure is often expressed using a logarithmic scale, in decibels (dB). Several specific metrics can be used to describe underwater noise. Three common metrics are the instantaneous peak sound pressure level (dBpeak), the root mean square pressure level (dBRMS) and the sound exposure level (dBSEL) referred to as the peak, RMS and SEL levels, respectively.During impact pile driving, the peak pressure represents the instantaneous maximum pressure, either overpressure or underpressure, observed during each pile strike. The RMS level is the square root of the mean of the square of the pressure during the duration of the impulse; it is the average pressure level of the pile strike from beginning to end. The cumulative SEL (SELcum) is calculated by summing the cumulative pressure squared and integrating over time of duration of the pile strike. SEL is used as an indication of the cumulative energy of a pile driving event, which may consist of one or many pile strikes.Regulatory agencies use these metrics to help characterize the noise pressure levels that can affect sensitive species. Some of the most frequently encountered biological thresholds in the Northwestern United States that are used by regulators to describe potential impacts to sensitive species are summarized in the following table. Agencies have defined thresholds for different types of injury, either hearing or bodily harm, and for temporary injury or disturbance."

Jan 1, 2017