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By D. M. Holloway

As a part of the 1-15 Reconstruction Project, static and dynamic (high-strain) testing methods formed the basis to estimate long-term axial capacities, and to assess the magnitudes of bearing capacity gains (setup) from the end of installation to the time of static/dynamic tests weeks later. This paper summarizes the results of nine full scale pile load tests to failure in compression, and how the designers used these data to finalize pile selection and penetration criteria bridge-by-bridge in the final design stages. Soil conditions along the project alignment ranged from deep, lightly over-consolidated Lake Bonneville clays interbedded with granular strata of varying consistency, to sites dominated by dense alluvial deposits of cohesionless soils well above the water table. The test sites were selected to bracket the conditions that are expected. Twelve-, 16-, and 24-inch-OD pipe piles are to be used to support the new bridges. The team plans to impact-drive all piles closed-end to final penetrations. The test piles varied from 35-ft-long pipes driven to refusal in the shallow dense sands at some sites, to 115-ft-long pipes stopping at 3 blows per foot in predominantly cohesive deposits. The capacities gained with time proved to be reasonably predictable, and significant setup was noted both in the cohesive and cohesionless strata. The test program objectives included providing the means to estimate long-term capacities from short-term (24- to 48-hour) restrikes following installation of foundation piles during production driving operations.

Jan 1, 1998

By Alok Bhowmick

The most uncertain and challenging part of a bridge design and construction is the ‘Choice of foundation’. During the planning and conceptual design stage, it is extremely important to choose the right type of foundation. Wrong choice can lead to disaster for the project. This paper will present three interesting case studies of past bridge projects, to demonstrate how correct choice of foundation can help to meet the project commitments while the wrong choice of foundations can led to huge delay in project completion, leading to time and cost overrun.

Nov 1, 2022

Jan 1, 1986

By Donald Bruce, Alex Reeb, George Filz, Wesley Schmutzler, Mitsuo Nozu

"One million seven-hundred thousand cubic yards of deep mixing were installed to support an elevation raise of an earthen levee known as LPV 111, which is located in east New Orleans. The deep mixing was done by two contractors using somewhat different technologies, but producing elements of the same size. As part of the quality control and quality assurance program, 507 deep-mixed elements were cored and 5,082 specimens were strength tested in unconfined compression. This paper presents data from the coring and testing program. Very high percentages of the core run lengths were recovered, except during one period for one mixing technology. The coring methods are described, and reasons for the isolated episode of low recovery are discussed. The strength data show that the specification acceptance criteria were satisfied. Statistical parameters of the strength data are provided, and trends between strength and the following factors are discussed: depth, soil type, binder factor, and project-specific experience. Photographs of longitudinal cuts of core specimens are presented. Important lessons learned from this unusually large project are described.INTRODUCTIONThe Lake Pontchartrain and Vicinity Hurricane Protection system included a project known as LPV 111, which is an approximately 5-mile long segment of levee and floodwall located in east New Orleans along the Gulf Intracoastal Waterway and adjacent to Bayou Sauvage National Wildlife Refuge (Cali et al. 2012). The majority of the project consisted of a raise of an existing earthen levee from an existing crest elevation of about 18 ft to a new crest elevation of about 28 ft. The underlying soils were weak and compressible, providing inadequate support for the raised levee. Ground improvement in the form of deep mixing was selected to provide the necessary stability and settlement control for the raised levee.The US Army Corps of Engineers (USACE), New Orleans District, was the governmental agency in responsible charge of the project, including approval of design, construction, and payment. The lead designer was URS Corporation, and the general contractor was Archer-Western-Alberici (AWA), working in alliance with TREVIICOS South (Trevi), who, together with Fudo Construction (Fudo), performed the deep mixing.As part of the quality control and quality assurance program, over 500 production deep-mixed elements were cored, the cores were carefully logged, and over 5,000 unconfined compression tests were performed. In addition, selected specimens were carefully photographed before and after longitudinal saw cuts to expose the interior of the specimens. This paper provides a summary of the coring and testing performed on the production deep-mixed elements."

Jan 1, 2015

By Serhan Guner, Sundar Chiluwal

Although significant research has been conducted on helical piles, there is a lack of research and official design provisions on the helical pile-to-pile cap connections. These connections may govern the global response of pile cap systems—especially in tall and light structures where uplift forces dominate the response. To improve future industry practice, the objective of this study is to understand the influence of pile-to-pile cap connections on the global behavior of concrete pile caps and develop recommendations for their efficient design. For this purpose, 108 high- fidelity nonlinear finite element simulations are conducted to quantify the influences of bracket type, embedment depths, longitudinal reinforcement percentages, shear span-to-depth ratios, and loading conditions on the load, deformation, cracking, and failure behavior of concrete pile caps. The results indicate that the design configurations involving single bracket type may result in premature concrete cracking around the anchorage zones with a 25% reduction in the uplift load capacity. The investigations also confirm that high reinforcement percentages and low shear span-to-depth ratios result in higher load resistance in all bracket types, and that the load capacities of the double and studded bracket types are similar. For applications requiring the use of lower embedment depths, it is recommended that either double or studded bracket types be used. The research findings have applicability to both helical and micro piles given that both include similar connection types. INTRODUCTION Tall and light structures may experience significant uplift forces at their foundations due to large overturning moments from wind or other lateral loads. Helical piles (e.g., Fig. 1a) can provide a cost- effective, practical, and resilient solution for resisting significant uplift forces. In order to realize the full potential of helical piles, it is imperative that the helical pile-to-pile cap connections (see Figs. 1b, c and d for examples) are properly designed to resist the applied forces. However, there is a lack of research and associated knowledge on the influence of pile-to-pile cap connection detailing on the global response of pile caps.

Jan 1, 2019

By Charles M. Wilk, Lori Tiefenthaler

"Information presented in this paper can be used to support deep soil mixing, subsurface grouting and slurry wall technology as sustainable construction technologies. Ordinary Portland Cement (OPC) is the default cementitious material used by Deep Foundation Institute (DFI) Members for geotechnical work. Owners, engineers and contractors can contribute to the sustainability of a geotechnical project by increasing the use blended hydraulic cements and industrial byproducts to replace some of the OPC in mix designs. Sustainability is defined as the quality of not being harmful to the environment or depleting natural resources. Production of cementitious materials consumes natural raw materials and energy while also generating air emissions and waste. Life Cycle Assessments can be used to compare the relative environmental impacts of one cementitious material to another. Blended hydraulic cements (BHCs) are interground (or blended) mixtures of Supplementary Cementitious Materials (SCMs) with OPC. Commonly used SCMs include fly ash, ground granulated blast furnace slag (GGBFS) and limestone. Examples of industrial byproducts commonly used in geotechnical work include coal combustion residuals (CCR) (aka fly ash), and ground granulated blast furnace slag (GGBFS). Much of life cycle impact of these SCMs and industrial byproducts have already been borne by the industries that generated them. There is increasing awareness to LCA and sustainability of different materials used on projects. This is evident in the application of the Leadership in Energy and Environmental Design (LEED) program. The savings in environmental impact with the use of SCMs and industrial byproducts can make proposed use of these materials in a geotechnical project more attractive in terms of sustainability. This paper presents (a) information that compares published life cycle assessment data of OPC, BHCs, and slag cement (SC) to illustrate the potential benefits to sustainability and (b) general strategies for positioning a geotechnical application, use, project design or cementitious material mix as a more sustainable alternative"

Jan 1, 2017

By Sina Z. Yekta, Zhangwei Ning, Pierre Frappin

This paper describes a DC (direct current) electrical resistivity method, which uses the contrasts in resistivity measurements to estimate the diameter of jet grouted columns as soon as they have been completed, with varying depth and water table, and without excavation. The measurement procedure is illustrated by several examples of application sites, including the Grand Paris tunneling works during the last 3 years where the method was systematically recommended in quality control for jet grouting works.

Sep 8, 2021

Jan 1, 1985

By Hamed Layssi, Farid Moradi, Thomas Tingson

This paper describes the feasibility and pilot study of of using existing non-destructive testing solutions for evaluating structural integrity and mechanical performance of mass concrete foundations. This paper includes two pilot studies using well-known NDT methods (i.e., Crosshole Sonic Logging and seismic tomography) for new applications (i.e., NDT inspection of mass concrete foundations). In the first case, we will examine an existing mass concrete foundation block with internal cracking, which has negatively impacted the strength and stiffness of the foundation block. A combination of pulse velocity and 2D tomography was used to evaluate the structural integrity in the foundation block. In the second case, the quality and integrity of newly built mass foundations were evaluated using Crosshole Sonic Logging (CSL). The methods are combined to locate potential sub-surface defects such as large voids and discontinuities. This paper aims to study the effectiveness of the NDT methods of Deep Foundations to assess the quality and structural integrity of new and existing mass foundations and explore the opportunity to extend the capabilities of these tests beyond their conventional use.

Sep 8, 2021

By G. Ranjan

The designers and the practicing engineers have started using latest and cost effective techniques of ground improvements which utilise the weak and poor sub-soil deposits efficiently for the civil engineering construction. In the present investigation, a new concept of 'skirted granular piles' has been advocated. An effective method of construction of granular piles as an economical alternative to vibroflot, and the skirt has been developed. The construction technique is based on indigeneous know how which effectively utilises the man-power technology avoiding import of costly equipment suiting to the developing countries. Full scale insitu tests have been carried out at four sites, having different soil conditions, on virgin weak sub-soil, and improved ground by casting plain and skirted granular piles. Effectiveness of different types of skirt has been demonstrated through insitu tests. A simple analytical approach has been proposed to predict the ultimate pile capacity. The predicted values of ultimate capacity have been found to demonstrate a good correspondance. Granular pile behaviour in terms of pile depth, diameter, spacing and stress deformation characteristics of the improved ground have been discussed. A significant improvement in ultimate capacity in improved ground has been noted. This is further augmented when granular pile group is skirted.

Jan 1, 2010

By Amit Srivastava, Monica Malhotra

In a congested city or urban area, so called “lifeline of the city”, i.e. Gas, Electricity, telecommunication, as well as other utilities or facilities are supplied or transported underground through buried pipes or utility tunnel. Sometimes these buried pipes or utility tunnels are deep underground and interfere with the foundation of new structure. It is highly probable that a pile foundation is placed near an existing underground buried pipe or utilities tunnel and may influence its load bearing capacity. Hence, estimation of reduce load bearing capacity of the pile foundation placed near the existing buried conduit or utility tunnel is a complex soil-buried structure interaction problem. It is further complicated owing to uncertainty in estimation of geotechnical parameters of foundation soil due to measurement and testing errors, inherent soil variability and model transation. Under such circumstances, load bearing capacity is best assessed in probabilistic framework or through reliability analysis. The present study demonstrates how concept of response surface method (RSM) in conjunction with Numerical Analysis and First Order Second Moment (FOSM) methods can be combined to per the reliability analysis. The study answers the following question “reliability in reduction in the load bearing capacity of single pile placed near the existing underground pipe or utilities tunnel”. It is demonstrated that the approach provides first hand ination on the reduction in the load bearing capacity and then estimate the reliability of that estimation in terms of an index called Reliability Index (). Such preliminary investigation can be useful for advocating the detailed analysis as well as in the decision making for relocation of pile foundation.

Sep 1, 2022

By Gerald Verbeek, Erick Baziw

Cone penetration testing (CPT) is a popular and cost effective tool for geotechnical site characterization. CPT consists of pushing at a constant rate an electronic penetrometer into penetrable soils and recording cone bearing (qm), sleeve friction (fs) and dynamic pore pressure (u) with depth. The measured qm, fs and u values are utilized to estimate soil type and associated properties based predominantly on empirical correlations. The cone bearing measurements are highly susceptible to additive measurement noise for sandy, silty and gravelly soils. This measurement noise results in high peaks due to interbedded gravels and stones and low peaks due to softer materials or local pore pressure build-up. To date there has been little progress in filtering this additive noise aside from ad hoc techniques, which include discarding qm measurements and smoothing/averaging qm measurements. This paper outlines a qm filtering technique which attempts to put structure into the estimation problem. In this case, the dynamics of the cone bearing measurements are modelled within a state-space mathematical formulation and a Kalman filter (KF) is then utilized to obtain optimal estimates of qm. The mathematical details of the qm KF algorithm are outlined in this paper along with the results from a challenging test bed simulation.

Sep 8, 2021

By Gerald Verbeek, Erick Baziw

Cone penetration testing (CPT) is a popular and cost effective tool for geotechnical site characterization. CPT consists of pushing at a constant rate an electronic penetrometer into penetrable soils and recording cone bearing (qm), sleeve friction (fs) and dynamic pore pressure (u) with depth. The measured qm, fs and u values are utilized to estimate soil type and associated properties based predominantly on empirical correlations. The cone bearing measurements are highly susceptible to additive measurement noise for sandy, silty and gravelly soils. This measurement noise results in high peaks due to interbedded gravels and stones and low peaks due to softer materials or local pore pressure build-up. To date there has been little progress in filtering this additive noise aside from ad hoc techniques, which include discarding qm measurements and smoothing/averaging qm measurements. This paper outlines a qm filtering technique which attempts to put structure into the estimation problem. In this case, the dynamics of the cone bearing measurements are modelled within a state-space mathematical formulation and a Kalman filter (KF) is then utilized to obtain optimal estimates of qm. The mathematical details of the qm KF algorithm are outlined in this paper along with the results from a challenging test bed simulation.

Oct 1, 2021

By Ralphie Adams, Tiana Rasmussen, Ashley E. Shirer

Transmission line foundation designers must rely on limited subsurface information, from easily accessible locations, resulting in subsurface uncertainty, increased design risk and increased construction costs. This paper presents a different approach for foundation analysis conducted in mountainous and alluvial floodplains located northwest of Phoenix, AZ. The region is dominated by fault-bounded, northeast dipping mountain ranges, where rock types and drillability can vary from granite to intact basalt. The valleys between are comprised of “basin-fill” deposits ranging from conglomerates and cemented soils to lose alluvium. Recently deposited alluvial fills can vary in depth significantly from location to location due to erosion and deposition from active and historic hydraulic features. To limit the subsurface uncertainty for foundation design, a phased approach using geophysical surveys along with detailed geologic reconnaissance was employed. Both compression wave and shear wave velocities were measured in order to identify the depth and properties of loose erodible materials from more scourresistant cemented, conglomerate, and rock deposits. These analyses were used in combination with limited subsurface drilling and sampling to evaluate direct embedment steel pole foundations for over fifty structures. Post analysis results from limited construction drilling reports were used to assess this approach.

Sep 8, 2021

By Edmund J. Cardoza

WELCOME TO THE DEEP FOUNDATIONS INSTITUTE 26TH ANNUAL CONFERENCE AND WELCOME ESPECIALLY TO THIS SEMINAR ON NON-DESTRUCTIVE TESTING OF DRILLED SHAFTS, PRESENTED BY MEMBERS OF THE DFI DRILLED SHAFT COMMITTEE. MY NAME IS ED CARDOZA; I AM A VICE PRESIDENT WITH THE MILLGARD CORPORATION, A DRILLED SHAFT CONSTRUCTOR FOCUSING PRIMARLY IN THE EASTERN HALF OF THE UNITED STATES.

Jan 1, 2001

By H. Yoshida

Jet grouting was first introduced in Japan in the second half of the 1960s, approaching 50 years ago. By the end of the first 40 years, jet grouting from single to triple fluid systems had become a global technology. In the last ten years, progress in the jetting has been remarkable, and operational efficiency has improved. The quantity of carbon dioxide emitted in unit soil improvement has become one-third that of the initial technology. Meanwhile, technologies in waste recycling and horizontal jet grouting are also emerging. This paper discusses developments in the most recent ten years.

Jan 1, 2010

By Don Deardorff, Ke Yang, Yingcai Han, Ken Sorensen, Robert Kruger, Mark Petersen, Diane Fiorelli, Larry Goldfarb, Kathryn Petek, Kwabena Ofori-Awuah

Design of deep foundations for lateral loads requires an understanding of soil-foundation-structure response during loading. Lateral loads on a deep foundation (piles) could be due to earthquakes, winds, waves, and/or machine vibrations. Over the years, analysis of response of piles due to lateral loads evolved from closed-form solutions to p-y methods to strain wedge to finite element/finite difference modeling. Although analysis of lateral response of piles and shafts is routinely performed, there is no single guidance document and/or standard for design and testing. Several different analytical methods are available for the analysis, and the resulting design can result in significantly different responses which can create confusion. This is especially true for analyzing and designing piles in potentially liquefiable soils with lateral spread issues under seismic conditions.This guidance document is intended to assist geotechnical engineers, pile designers, and contractors in analysis, design, and testing of piles and drilled shafts for lateral loads. This document discusses the background of different analytical and testing procedures and presents the recommended methods for analysis, design and testing of piles for lateral loads.Chapter 1 defines the different kinds of lateral loads to which a single pile or pile group may be subjected. This first chapter also presents different types of piles used to resist lateral loads.Chapter 2 discusses geotechnical issues related to lateral pile design such as liquefaction and lateral spreading and other non-seismic issues. Also addressed in Chapter 2 is geotechnical site characterization (as related to lateral loads) in terms of site investigation, in-situ testing, geophysical testing, laboratory testing, and estimation of soil/rock properties.Chapter 3 discusses the background and available analytical methods and tools for the analysis and design of single piles and drilled shafts. Several methods of analyses from closed-form elastic solutions to the finite element/finite difference solutions and their applicability are discussed. Available commercial computer software packages for analyzing single piles and drilled shafts are also presented.Chapter 4 expands the discussion of single piles and drilled shafts into the analysis and design of pile groups. In addition, group effects, resistance of pile caps, results of previous experimental and analytical studies, and available analysis tools and software for pile groups are discussed.Chapter 5 presents the issue of lateral resistance of piles and drilled shafts as discussed in different national and international building and non-building codes. A summary of extensive research on several codes are presented to facilitate the compliance with different codes.Chapter 6 discusses structural design issues of individual piles and drilled shafts such as depth of fixity.Chapter 7 discusses soil structure interaction issues related to kinematic and inertial effects due to seismic loading and available methods of analyses.Chapter 8 discusses and presents the typical procedures for the lateral load testing of piles. This guideline was developed as an aid to the practicing engineer in providing information, direction and commentary on the lateral design of deep foundations. Although all reasonable effort has been made to accurately compile the material and information contained herein, no warranty is made with regard to any such material or information and the Deep Foundation Institute assumes no responsibility for any possible errors or any direct or indirect result of the use of any such material or information. It is not intended that this document address every factor affecting lateral design for every situation. Therefore it is the responsibility of the person utilizing information from this document to confirm that it is appropriate and correct for their situation as well as to understand and properly apply

Jan 1, 2012

By Riad Diab

In 2018 the Caisse de Dépôt et Placement du Québec (CDPQ) awarded a $6.3 billion (U.S. dollars) design-build contract to the Joint Venture (JV) team NouvLR for the design and construction of one of the largest automated transportation systems in the world, called the Réseau express métropolitain (REM). The REM project is a 67 km (41.6 mi) light rail system with 26 stations linking downtown, the airport and the greater Montreal area in Canada. Out of the 67 km (41.6 mi) network, over 25 km (15.5 mi) is being constructed on a 650- span elevated structure founded on single drilled shafts socketed into rock. Optimizing the design of the drilled shafts was one of the main objectives of the geotechnical team, as it would likely result in shorter shafts that help significantly reduce the project costs. As part of the optimization process, three static axial load tests and two fully instrumented lateral load tests were performed, during the preliminary design phase, on sacrificial shafts to simulate the ultimate load level and validate construction procedures.

May 1, 2022

By Paikowsky, Samuel G.

"Due to the way drilled deep foundations are being constructed, their structural integrity and geotechnical capacity are highly variable. Drop weight systems are increasingly being used to dynamically test the capacity and integrity of drilled deep foundations. Conventional pile driving hammers are often either inadequate or not economical to test these foundations and drop weight systems have therefore been developed to allow for dynamic testing.The advantages of the tests include high mobility, short testing time, low cost relative to static load tests (allowing multiple tests at a single site), and integrity/construction quality evaluation concurrent with capacity determination. The dynamic testing method for drilled deep foundations encounter several difficulties including: the need for a pre-testing analysis for matching pile, soil and testing system, adequate mass and drop height to reflect the mobilized capacity without structural damage, test interpretations for irregularly shaped and/or non-uniform piles, need for reliable dynamic measurements depending on the impact and the distance between the impact and the measuring point, and limited knowledge about the accuracy of the predictions.The principles of the tests are presented using simplified models and demonstrated via a case history. Drop weight systems are reviewed. Dynamic measurement principles are explained and the construction and testing quality effects are outlined and demonstrated via numerical modeling and case histories. A comparison of dynamic and static tests is presented via a database, case histories and finally a short review of relevant codes is provided.1 IntroductionTraditional static axial load test is performed by a slow application of a force produced against independent reaction, imitating structural loading. It is the most reliable method to determine the pile’s performance as commonly required under typical service conditions. The major limitations of this testing are: (i) high cost associated with set-up, test duration, interpretation and construction delays, and (ii) inability to obtain information about the pile-soil interaction along the pile without additional testing means (e.g. tell tales, strain gauges, etc.). These limitations are acute when high capacity foundations are involved."

Jan 1, 2015

By Damir Dedic, Wörle. Patrick

"Soil properties within a construction project area are analyzed during the planning phase. However, it is only possible to achieve selective soil exploration, even in the case of very extensive investigatory programs, which results in a certain soil risk and uncertainties for planning and execution.Therefore, the application of monitoring systems is becoming increasingly important in the field of geotechnics. The application of suitable monitoring systems for these particular purposes provides considerable knowledge relating to the load bearing behavior of the soil and the ground anchor. Applications that present major challenges to measuring anchor forces include back-anchorages of long-lasting and very deep construction pits, construction pits in urban areas, slope and embankment supports for track and vehicular routes, port and lock structures, and uplift control. Apart from overseeing individual construction stages, monitoring systems analyze the interaction between the soil and structure throughout the latter’s entire life cycle and safeguard the functional capability of the applied system components. Geotechnical construction projects can be adapted, optimized and carried out with enhanced safety from the information obtained.Conventional Monitoring SystemsThere are numerous approaches for determining anchor forces of bar or strand anchors. Lift-off tests and measurements with load cells are the most common methods.Lift-off Test: Lift-off tests provide a possibility to monitor the prevailing force in strand or bar anchors. The entire anchor head structure is lifted using the appropriate equipment. The steel tendon is prolonged, or in the case of strand anchors, a screw-on cap holds the wedge carrier so that a tensioning jack can be mounted above it. Then, the tendon is prestressed until the lower anchor nut (bar) or wedge carrier (strand) is lifted off from the anchor plate. The intersection of the two straight lines in the figure represents the force at which the anchor nut or the wedge carrier lifts off from the anchor plate. Thus, the intersection displays the actual load of the anchor. This form of anchor force control gives conclusive results, but at the same time requires extensive accessories and extra personnel to execute the test. For this test, a sufficient bar overhang must be available, the wedge plate must possess an external thread, or there must be a strand overhang of at least 24 in (60 cm). Furthermore, the anchor head must be freely accessible and in a position to be reached with the necessary equipment."

Jan 1, 2017