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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 John P. Turner, Benjamin J. Turner

"Non-destructive testing and evaluation (NDT/NDE) methods have become standard tools as part of the post-construction quality assurance of drilled shaft foundations. In responding to anomalies, foundation designers, owners, and contractors face a number of choices, including: (i) acceptance of a shaft with known anomalies, (ii) further investigations of integrity (e.g., concrete coring), (iii) repair schemes, and (iv) reject and replace. To assist in selecting the best option, analyses are often performed that involve assessing the structural performance of reinforced concrete shafts that may include defective concrete or voids. Currently, the analytical tools for predicting the flexural strength and stiffness of drilled shafts with defective concrete located in discrete regions of the cross section are limited. This paper presents a robust moment-curvature analysis tool for drilled shafts based on the fiber-element discretization method. The tool allows for consideration of anomalous or defective concrete regions in the shape and location that they are believed to exist in the shaft while considering explicitly the nonlinear material behavior of the intact regions based on expected material properties. A case study is used to illustrate the practical application of the analysis to drilled shaft projects.INTRODUCTIONImperfections such as defective concrete or accidental eccentricity of reinforcing cages are an inherent part of the drilled shaft construction process that will occur occasionally even when construction best-practices are followed. Petek et al. (2002), O’Neill and Sarhan (2004), Poulos (2005), and others have described the effects that construction defects can have on the axial and lateral performance of drilled shafts. Our industry has seen rapid progress in recent years in the development and improvement of tools for detecting drilled shaft anomalies, such as gamma-gamma and crosshole-sonic logging, sonic-echo testing, thermal integrity profiling, and even visual inspection with invasive video cameras. Nonetheless, in most cases the wealth of data from these tests is used by foundation engineers to make a fairly “black or white” decision—should the defects be repaired, or should the shaft be rejected? A third option that is not typically considered is to directly analyze the section, including anomalies, and compare the reduced strength and/or ductility to the actual project demands. This option takes full advantage of the data collected during integrity testing, and may provide a justifiable means for avoiding further construction costs and delays, whether for repair or replacement."

Jan 1, 2016

By Laurel E. Blackman

The DFI Project Information Management Systems (PIMS) Committee cooperated with the US Army Corps of Engineers (USACE) to develop a specification for PIMS used on USACE projects. Once completed the Committee developed a more generic version of this specification for general use, which is contained in this document. This first edition has simply removed the USACE-related requirements from the document. The committee will continue to work on this specification to enhance the content and also incorporate recent technological development for these systems. It is the Committee's intention that a second edition will be issued in 2022.

Jan 1, 2021

By Pete Howell, Patrick Granitzki, Alicia Plinio, Janitha Batagoda

The New York City Housing Authority (NYCHA) Red Hook Houses was subjected to damage during Superstorm Sandy. As a result, the NYCHA has an ongoing project known as Restoration Associated with Sandy Recovery Program to improve the resistance against future storms. The specific project included 28 residential buildings and several service buildings within the Red Hook Development. The subsurface conditions within the eastern portion of the site included existing fill material underlain by varying stratums of very loose, loose and medium dense silty sands followed by very soft to medium stiff clay or dense silty sands. The western portion of the site included existing fill material, very loose to medium dense silty sands and organic clayey silts underlain by very soft to medium stiff sandy silts. Based on the geotechnical report, a conventional driven steel pile system was specified containing two pile depths. As part of the project bidding, an alternative pile type was recommended and analyzed to provide quicker installation, reduce vibrations, reduce noise, and provide relatively large cost savings. Due to relatively high lateral loading, an innovative double steel casing drilled displacement piles was proposed as the alternative pile option. Field testing proved the piles capable of the required project capacities and the use of drilled displacement piles as the best alternative for the project and accepted by the NYCHA.

Oct 1, 2022

By Paul Thurlow, Richard K. Lipscombe

The measurement of deflection of designed diaphragm walls is critical for near real time information to assess wall and soil behaviour as the internal area is excavated in a controlled manner. Data enables the site team and designers to check performance of the design, which is linked to safeguarding the site and the external stakeholders.This paper documents the use of Shape Accel Arrays at the Tottenham Court Road Western Ticket Hall during excavation and propping within the diaphragm wall for the Crossrail project. It shows how the data obtained was used within the site settlement management plan to assist in the control of the works and the information used for Value Engineering purposes that benefitted the project.The use of Shape Accel Arrays for measuring the deflection of retaining walls is not commonplace in the UK construction industry, with the Tottenham Court Road Western Ticket Hall being one of the first times they have been used in such a way. A detailed analysis of the data obtained from the instruments has been undertaken, and compared to the results obtained from the manual inclinometers that were read next to the SAAs. The advantages of the relatively new SAAs have been discussed, as well as other applications of the instrument.

Jan 1, 2017

Jan 1, 1998

By Franz-Werner Gerressen

New developments are required each day as our industry becomes more competitive. To improve performance, continue and to ensure future demands can be met. This requires the development of technical support systems that enable a more constant delivery and quality of installation of pile foundations and other applications. For example: assistance systems capable of relieving the machine operator of automating monotonous or repetitive operations. Real time installation control of the production process to manage quality control, or data transfer and reporting systems capable of keeping pace with the digital future. This paper will describe these new approaches and considerations required for these new developments. The paper also describes the equipment which is needed to execute the work under the various conditions and provides references herein. INTRODUCTION The success of a construction site is influenced by a number of factors. Selecting the most efficient and economic methods during the planning phase to defining the right direction. This means having multifunctional equipment available. To ease the usage of this equipment by the operator, uniform operation and control systems are essential. Systems like this can provide uniform handling procedure for more than 20 different installation techniques. Experienced operators are not always available. Therefore, to ease the start for beginners and to support training, numerous assistance systems were developed. This ranges from simple information for controls shown on the monitor avoiding misuse to systems which can partly automate the construction process. Regardless, the best equipment is not enough when the construction is not running smooth. The control system not only helps to organize and coordinate service of the equipment; moreover, it allows the operator to control the quality during the installation process reacting if needed. It allows process optimization as well as documentation which might be required for later negotiations.

Jan 1, 2019

By Seth Robertson, Daniel Belardo, Travis Coleman

Thermal Integrity Profiling (TIP) is a non-destructive method used to evaluate drilled deep foundation integrity. This integrity testing method is specified more frequently, and is becoming an industry standard in the transportation and private construction sectors. This testing method utilizes heat generated during the concrete/grout curing process to assess deep foundation integrity over the evaluated length. With compilation of the measured temperature versus time and installation records, a model of the Effective Average Radius versus measurement depth is generated. The generated effective shaft model is highly dependent on specific construction details, subjective modeling parameters, and proper interpretation of concrete/soil heat dissipation characteristics. Key components of the TIP analysis include both qualitative and quantitative assessments. Qualitatively, variations or sharp reductions in temperature profiles may indicate potential anomalous regions. Quantitatively, a correlation is established between measured temperatures and estimated Effective Radii for subsequent integrity evaluation. Best practices in processing the TIP measurements are presented, including selecting the optimal time for analysis, normalizing the thermal profile, and proper interpretation of potential anomalous regions. Recommendations for implementing mitigation efforts and interpretation of the TIP results are presented.

Sep 8, 2021

By John L. Walkinshaw

It is obviously not possible in the time given me today to review in great detail all the research of the past 20 years that the (FHWA) has sponsored or participated in. In this presentation I will highlight some of the principal programs that I am familiar with. This handout lists practically all the reports prepared for the FHWA involving deep foundations and some related work involving the same structural elements (piles, shafts, ground anchors).

Jan 1, 1993

By Nicolas Moscoso, Gerald Verbeek, Marcel Bielefeld, Rob van Dorp

Upon recently, most offshore foundations were based on a number of driven piles that were installed with an impact hammer. With the increase in offshore windfarms two major developments have occurred: the shift from jackets to monopiles, leading to increase of the diameter of the foundation piles, and a shift from impact hammers to vibro hammers. As the use of vibratory hammers is becoming more and more common practice, the need for accurate vibro-driving simulation software has increased, which requires that the soil modelling is enhanced to address soil fatigue during pile driving and to predict reliably the soil behavior and resistance during pile driving. In addition pile driving monitoring, which is routine for piles driven with an impact hammer, needs to become common practice. This paper addresses advances in soil modelling that allows more accurate pile driving simulation as well as the application of Vibro Driving Analysis (VDA) or Monitoring (VDM) to validate the simulation results. This is illustrated by a case study of the test pile for the Delft Offshore Turbine project, a 28 m long monopile with a diameter of 4 m that was driven 15 m into dense sand layers using a vibro hammer. After some 6 months the pile was extracted, and pile driving simulations and VDA were done both for the installation and extraction phase. 1. INTRODUCTION At the end of 2017, the total worldwide offshore wind power capacity was 18.8 GW [1]. The vast majority of offshore wind farms are currently in Northern Europe, which together account for over two thirds of the total offshore wind power installed worldwide, followed by East Asia, while developments in North America are still in very early stages.

Jan 1, 2019

By Vijayakumar Viramuthu, Martin Heinrich

Tower of Lot L, L1 & M, Kuala Lumpur City Centre when completed would stand 700 m tall. This Mega tall Skyscraper would merely be less than 500 m away from the world tallest Twin Tower, the Petronas Twin Tower. From June 2018 to February 2020 BAUER (MALAYSIA) SDN. BHD. constructed 225 nos bored piles with diameters of 2.0 m and 2.5 m for this tower. To comply with the depth requirement of the initial design and the need to have the pile toe 2.0 m above competent bedrock, the drilling equipment was required to be able to achieve a maximum drilling depth of 150 m. Actual piles constructed on site were deeper than 120 m. These dimensions caused superlative challenges which included but were not limited to controlling the open borehole stability over time with polymer, installing 70 t heavy steel cages and pouring up to 550 m³ concrete continuously in conjunction with installation of 88 t heavy kingposts into workable fresh concrete. The piling works were executed with one BAUER BG 48 and one BG 72, the biggest drilling rig globally available.

May 1, 2022

By Yazen Khasawneh, Osvaldo P. M. Vitali, Mohammad Nassim

The demand for renewable energy is growing as the conventional energy resources are becoming more limited and we are more conscious about the negative impact of conventional energy sources on the environment. Wind turbines technology is evolving in a fast pace, the towers are becoming taller, and the rotors are getting larger. The challenge is to maintain the Levelized Cost of Electricity (LCOE) as low as possible to ensure a sustainable and an economically feasible energy supply. Thus, the foundation systems for wind turbines should evolve to meet the increasing load demand, while reducing the LCOE. In this paper, an innovative foundation system for onshore wind turbines is presented. The new foundation system is the conventional P&H tensionless pier foundation (PHTP) with a reinforced concrete collar at the top of the pier. 3D FEM modeling was conducted to assess the benefits achieved by adding a collar at the top of the PHTP foundation. The numerical results show a significant performance enhancement of the proposed foundation system over the conventional PHTP foundation. The enhanced foundation system also has an economical advantage because the depth of the pier can be greatly reduced while maintaining a superior performance.

Sep 8, 2021

By Terence Ma, Seok hyeon Chai, Jeff Lam, Thamer Yacoub, Brigid Cami, Sina Javankhoshdel

The Limit Equilibrium (LE) analysis of pile-supported geotechnical structures normally assumes a constant shear force for the pile instead of considering the non-linear capacity of the pile which is related to the pile displacement. In this study, a 3D Limit Equilibrium analysis is carried out for a landslide model supported with piles by considering the constant and non-linear capacity of the pile which is computed using a separate Finite Element (FE) algorithm. The depth of the pile, soil layering, and the pile properties are used with an assumed maximum displacement to compute the geotechnical non-linear capacity of the pile. In this study, the results of the initial unreinforced 3D LE model was first compared to the 3D FE analysis results. Then, the pile pattern was applied to the failure region in the 3D LE model, and then the factor of safety was recomputed. The results of the constant shear piles were compared to the model with the non-linear piles.

Sep 8, 2021

By Jack Taggart, Chris Barker

Pile load testing strategies for large infrastructure projects and multi-phase building developments have historically justified cost and programme benefits for undertaking advance preliminary and working pile load testing. However, more recently piling and pile load testing strategies have included assessment of the embodied carbon to understand and present the carbon savings that can also be achieved. This paper gives an overview of the factors contributing to carbon and emissions in the construction of bored pile foundations and presents the methodology taken in assessing embodied carbon as part of the pile load testing strategy for a multi-phased building development in London. Potential embodied carbon savings for various bored pile types and load testing strategies are discussed alongside alternatives and other considerations including pile re-use and carbon offsetting to inform continual improvement for future projects.

May 1, 2022

By Henry H. Tayler, Eric Sturel

1 Triton Square was originally a six-storey building with a one-level basement located within a commercial development near Euston, London. It was designed and constructed in the 1990s and the foundation scheme comprised straight shafted London Clay piles arranged singly beneath columns. The scheme added three storeys and a five-storey infill in the central atrium area to increase the building floorplate by 70% and maintained the usability of the basement space. As the loads to support the additional floorplate area were greater than the capacity of the existing foundations, an optimised strengthening scheme of small diameter piles installed within the existing basement and a slender retro-fitted raft was installed to augment the existing piles. The re-use and strengthening of almost all of the existing foundations enabled re-use of a very high proportion of the superstructure and in approximately 35,000 tonnes of concrete and 1,900 tonnes of reinforcement and structural steelwork being re-used. The structural embodied carbon for the refurbished building scheme is estimated at an average of 136 kgCO2e/m2, achieving a Structural Carbon Rating Scheme (SCORS) “A” rating with components detailed in the paper.

May 1, 2022

By Yu Chuang, Zai Jinmin, Liu Songyu

"The piled raft foundation is a geotechnical composite construction method, consisting of three elements, piles, raft and soils, which is applied for the foundation in an increasing number. Differential settlements have numerous negative effects on a superstructure in piled raft foundations. Through the analysis of the production mechanism of differential settlements and differential settlements control measures, a method of adjusting pile configurations is presented to control differential settlements. By comparing the measured data and finite element method analysis of one oil storage piled raft foundation, the new method is verified that the differential settlements can be reduced effectively and the inner forces of foundations are more reasonable with varying length pile configurations. The differential settlements can be minimized or even reduced to zero with right pile length.INTRODUCTIONPiled raft foundations are widely adopted for the prominent advantage of limited settlements and adequate bearing capacities. However, there always exits differential settlements in conventional piled raft foundations. The differential settlement is the main cause that produces additional stresses in the structure. Differential settlements have numerous negative effects on a superstructure as well as on a foundation, and should be restricted to allowable limits. How to control the differential settlement is the key interest.An increasing number of structures are founded on piled rafts. For this reason, design strategies that enable an optimized design have a major importance for safety and economy. An optimized design may be defined as a design achieving maximum economy of the solution, that is minimum cost for the installation of the foundation."

Jan 1, 2005

"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 Peter Cali, Wesley Schmutzler

"The Deep Mixing Method (DMM) was employed to raise and support the LPV (Lake Pontchartrain and Vicinity) -111 Levee in New Orleans. Even using innovative technologies, the tight schedule to achieve the 100 year elevation by June 1, 2011 was a daunting endeavor. The size and scope of DMM proposed for LPV-111 was on a scale never attempted outside of Japan. Over 1.65 million cubic yards of DMM was installed. LPV-111 is adjacent to the Bayou Sauvage Wildlife Refuge, which is the largest urban National Wildlife refuge in the United States. By utilizing DMM to control settlement and improve stability of the taller levee, side slopes were steepened from the conventional 1V:4H to 1V:2.85H, thus avoiding encroachment into the Bayou Sauvage and reducing the amount of clay needed for the completed levee. The COE utilized Early Contractor Involvement (ECI) for this contract. The ECI process allowed for input from the DMM contractor, TREVIICOS South, in order to optimize equipment resources and material requirements. This paper gives an overview of the extensive DMM requirements for LPV-111 and explains the benefits of the ECI process.IntroductionDuring hurricane Katrina the levee that constitutes LPV-111 was overtopped and breached in several locations. The United States Army Corps of Engineers (USACE) was presented with the task of increasing the level of the flood protection around New Orleans after Hurricane Katrina to the 100- Year hydraulic grade - the level of protection that provides risk reduction from a storm surge that has a 1% chance of being equaled or exceeded in any given year - and the firm project completion deadline was June 2011.LPV-111 is located in East New Orleans and a large portion of the levee is adjacent to the Bayou Sauvage National Wildlife Refuge. The levee could not encroach on this area. This provided a limited footprint for the levee and made construction of conventional levee difficult, if not impossible. The total length of the project was 5.3 miles. Included in the project was the rehabilitation of one main pumping station and one smaller pump station for water management within the refuge. Short sections of “T” wall were used at the tie in at the Lake Borgne Surge Barrier, the main pump station and the CSX Railroad crossing"

Jan 1, 2017

By Bernardo J. Jiménez Vega, Edy L. T. Montalvan PhD

The experience gained during more than 900 Crosshole Sonic Logging (CSL) tests on drilled shafts shows the importance of establishing proper project acceptance and repair protocols. Drilled shaft evaluation is a multidisciplinary task that should not be left solely to the outcome of the CSL test. This test allows to characterize and delimit areas of different qualities of concrete, and it is important that all the interested parties understand the difference between flaws and defects. The information presented here is intended to give a guideline to contractors, inspectors, engineers, owners and clients on how to deal with acceptance and remediation of defective drilled shafts, detected using CSL tests. A database of flaws is presented depending on their location, intensity and remediation method. Procedures that allow the flaws to be analyzed are presented in order to dismiss or classify them as defects. In many cases, the CSL test may indicate an anomaly, but by coring the concrete and analyzing the structural demands and conditions, the flaw can be classified as non-severe. When flaws are classified as defects, their repair will depend on the area where they are located in the drilled shaft pile. In this document two procedures are described for repairing defects depending on their location. For defects in the drilled shaft head area, the procedure takes into account the interaction between the new and old concrete. For repairing the middle zone of the drilled shaft by grouting, the major concerns are the difficulty of accessing through the drilled shaft at deep depths and the communication between boreholes. For defects at the drilled shaft tip, two proposed remediation methods are presented. Finally, tomography tests are presented to compare the effectiveness of remediation by grouting.

Oct 1, 2022