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By John P. Turner, Benjamin J. Turner

"Tieback anchors are now used routinely for landslide stabilization in the USA and abroad. It is generally understood by design engineers that friction loss over the unbonded length of a tieback anchor is inherent to the system, and such loss is permitted as long as it does not exceed a certain threshold, typically 20 percent of the post-tensioning load. However, recent experience from projects utilizing tieback anchors with unbonded lengths in excess of 150 feet has demonstrated that this criterion may be difficult to achieve, particularly in certain ground conditions. Furthermore, anchor friction loss, even if below the 20-percent threshold, has important implications for the stability of the slope that are often ignored in practice. This paper presents the results of a study in which friction loss is quantified from load test data for projects in a variety of ground conditions by means of a “wobble coefficient.” Factors that may influence the wobble coefficient are examined, and recommendations for addressing this issue in practice are presented. A recent instrumented load-test program for a landslide stabilization project in Southern California is examined, demonstrating that with appropriate monitoring controls, uncertainty with regard to friction loss can be minimized. IntroductionSteel-strand tieback anchors have been used by the geotechnical community to support shoring systems for many decades, and more recently as a means to stabilize landslides. For strand encased in grease-filled plastic sheathing, which is intended to allow the strand to elongate freely, some load can still be transferred by friction between the strand and the grease and between the grease and sheathing. The sheathing then transfers load to the surrounding grout and, in the case of ground anchors, to the surrounding soil or rock. The resulting decrease in load over the length of the unbonded zone is known as “friction loss.”A widely used criterion for ground anchor acceptance based on load testing is that the measured anchor elongation must achieve a minimum value of 80 percent of the theoretical elastic elongation, or in other words the actual elongation can be up to 20 percent less than the theoretical value. This ensures that the majority of the load applied at the anchor head is reaching the bond zone behind the assumed failure surface, since load shed within the failure mass does not contribute to stability. This criterion acknowledges that friction loss is an inherent feature of the anchor system which cannot be eliminated completely, only minimized."

Jan 1, 2017

By Anup Kumar Mandal, Sanjoy Chowdhury, Biswajit Das

"Tailing pond of an iron ore mine necessitated raising the height of its embankment to create additional storage capacity. The tailing pond is located in eastern India and raising the height of embankment was going on during the month of January, 2014. Upstream method of construction was adopted since there was no space available at the downstream side. During the construction, about 200 m stretch of the north east embankment of height about 5.5 m failed forming a classical slip circle on the upstream side involving about half the top width of the embankment. To find out the root cause of the slope failure, detail geotechnical investigation work was carried out within the embankment as well as in the adjacent areas within the pond. About 7.5m thick very soft tailings were detected below the constructed embankment. Shear strength of the soft tailing was very low and was inadequate to sustain imposed embankment load. This resulted in the failure of the embankment. Analysis of the tailing deposit revealed that even after failure, settlement was continuing due to imposed embankment load. Under normal onedimensional consolidation, the tailing deposit would have taken about 5.7 years for 90% of primary consolidation. However, in order to mitigate the scarcity of storage space, mining plan required raising the height of the embankment within next six to eight months. Therefore, despite the fact that there was a failure, it was necessary to continue the construction on the underlying weak stratum. The system was redesigned with installation of prefabricated vertical drains (PVDs) to accelerate the consolidation process thereby gaining the in-situ strength. Strength was additionally enhanced by installing geogrids in multiple layers. It stabilized the existing embankment and also ensured construction of additional height over and above the existing embankment.INTRODUCTIONBeneficiation plant in the Iron mines enhances the mineral content by separation of contaminants and fines. The residue (waste material) is called tailings/tailings depending upon the grain sizes. These tailings in a slurry form are generally disposed in a pond called as tailing pond/tailing pond. Height of embankment of such ponds is increased either by upstream or by downstream or by centrally raising methods in different phases as quantum of deposition in the pond increases with time."

Jan 1, 2015

By Osama A. Safaqah

Driven plate anchors can be used to hold in place large bridge caissons during floating construction. Their small size and simple method of installation make them a very cost effective alternative to other direct-embedment, gravity, and drag anchors. The geotechnical design of plate anchors involves the anchor geometry, embedment, drivability, and proof testing. This paper describes the experience gained with plate anchors used during construction of the new Tacoma Narrows Bridge. For this project, the anchors had to be driven in dense to very dense sands, and had to resist large forces from 7-9 knot currents.

Jan 1, 2013

By Negin Khalili-Motlagh-Kasmaei, Paul O'Leary, Christopher J. Rothsiedl, Dimitar Ninesvski, Alexander Zöhrer, Vincent Winter

This paper presents the implementation of a digital twin for the vibro-replacement ground improvement process, as part of a digital construction site. The goal is to implement an evidence-based quality assurance for each produced element (column or point). The system uses a combination of planning data and real-time machine data collected automatically from construction equipment. In addition to the quality assurance, feedback is provided in a number of areas, e.g., condition monitoring of the equipment. The digital twin builds upon the real-time sensor and machine data, fused with metadata, to implement a digital model for the process. A hierarchical data evaluation, using rule-based Key Performance Indicators (KPIs), permits viewing of the spatial variation of data over the construction site. This permits the modelling of systematic variations in subsurface properties across the site, enabling the detection of anomalous individual elements, the diagnosis of their cause and the prediction of properties as construction proceeds over the site. All time-series data and KPIs are represented by standard classes of objects, leading to a generic coding of the data analysis; this minimizes the effort required to add additional sites and/or new KPIs. Examples are presented for a number of sites, where the system was used to identify anomalous columns.

May 1, 2022

By Andrew Moran, William H. Walton, Matthew D. Emrick, Mary C. Nodine

"A rapidly growing company in the northern US needed a large auditorium built into a dolomite bedrock hillside. The structure required an 80-foot-deep earth retention system independent of the auditorium foundation and superstructure. Allowable wall movements were limited to less than two inches. A 60-foot-tall permanent shotcreted soil and rock nail wall was designed for excavation support. The soil and rock nail wall utilized both active (post-tensioned) and passive nails, with capacities and installation angles optimized to address varying soil and rock conditions and to support heavy surcharges. The wall was configured with three two-foot-wide benches to facilitate controlled blasting and removal of more than two million cubic yards of soil, limestone and dolomite bedrock, and featured a permanent cast-in-place concrete face and a robust waterproofing and drainage system. A 20-foot-high reinforced concrete retaining wall was required at the top of the soil and rock nail wall to raise grades, resulting in a large surcharge.Design of the soil and rock nail wall was initiated less than three months before the start of construction, requiring expedited geotechnical explorations, analyses, design, and construction that would occur simultaneously. Design changes were made to address the discovery of a weak clay residuum seam at depth running along the base of the excavation, as well as significant changes to the building footprint made after the start of construction. Extensive performance monitoring was conducted during construction to measure vibrations and movements.Introduction and Project BackgroundA fast-growing company in the northern United States had a need for 600,000 square foot, 11,000 seat auditorium as part of its campus expansion. The auditorium was built underground, into a hillside to preserve the views of rolling terrain and farmland beyond. It featured a green roof and rockwork facing that mimicked regional geologic formations. The sixstory building required up to 80 feet of earth retention, including 60 feet of excavation beneath existing grades.As concepts for the project evolved, it became apparent that due to the geologic conditions, space limitations on site and the depth of cut required, a standard counterfort wall system would not be feasible. With groundbreaking for the building three months away, Thornton Tomasetti (structural engineer) engaged GEI Consultants, Inc. (wall design engineer) to design a 1,600-foot-long permanent soil and rock nail wall to support the excavation. The wall design engineer implemented a geotechnical exploration program immediately and began the design process, coordinating closely with Nicholson Construction (specialty"

Jan 1, 2017

By Brian T. Nereson, Michael C. Penney

"This technical paper was prepared to describe the general process by which the authors designed a column-supported load transfer platform (LTP) for support of asphalt-paved runway and taxiway embankment areas over soft organic soils, the major tasks and observations made during construction of the system, and the outcome of the system design and construction. The LTP system was designed using the method described in the BSI Standards Publication Code of Practice for Strengthened/Reinforced Soils and Other Fills, BS 8006-1:2010 (BS8006), to achieve performance objectives for the project. The design also used other criteria based upon the authors’ engineering experience and understanding of the expected interaction between soils, structures and geotextiles. The design and construction process described herein resulted in a successful project. The authors identified that full-time engineering oversight during construction was of high importance and provided a high degree of value to the project. The authors’ intimate knowledge of the potentially adverse effects of variations in construction practices promoted timely identification of construction deficiencies that could have affected the reliability of the system. This resulted in corrections and modifications being made, while materials were still accessible, to protect the intended performance of the finished system.INTRODUCTIONThe site is located in Marshfield, Massachusetts. The surrounding area is flat and contains significant wetlands with a water table at or near the ground surface. Prior to the improvements described herein, the site was already developed as an existing municipal airport with an approximately 3,000 linear-feet asphalt-paved runway oriented in a northeast/southwest direction (northeast end referred to as Runway 24 and southwest end referred to as Runway 6; Fig. 1). The site is located approximately 0.5 to 1 mile (Runway 24 and Runway 6, respectively) from the Atlantic Ocean.The improvement project included total extension of approximately 550 linear feet of asphalt-paved runways and taxiways over existing wetlands that consisted of soft, organic soils with varying but significant depths (Fig. 2). An initial geotechnical assessment performed for the project identified that the subsurface conditions were not suitable to support the proposed runways and taxiways in their existing state."

Jan 1, 2016

By Fawad S. Niazi

Analysis of deep foundations in terms of axial capacity has been a topic of great interest in the soil-structure interaction problems. Soil behavior is governed by a series of complex stress-strain changes that occur during pile installation and subsequent loading. Owing to the difficulties and uncertainties on the basis of the soil strength-deformation characteristics, one of the most frequently followed design practice is to refer to the formulae correlating directly the pile axial capacity components of unit base resistance (qb) and unit shaft resistance (fp) to the data collected from cone penetration test (CPT), i.e. to the tip stress (qc or more proper qt), sleeve friction (fs), and shoulder pore water pressure (u2). The elementary basis for such formulations has been the idea of considering cone penetrometer as a mini-pile foundation. This has resulted in plethora of correlative relationships in the past over 60 years. Such correlations, although empirical, have been worked out on the basis of load test results from both instrumented and un-instrumented full scale piles and are able to accommodate many important variables. A quick review of the evolution process and development of such design formulations is presented with a view to propose recommendations for future research directions, where the latest version of CPT i.e. seismic piezocone test (SCPTu) can be used to advance from capacitysingularity to the complete axial pile load–displacement (Q–w) response.

Jan 1, 2013

By John P. Turner, Steven S. Dapp, Dan A. Brown

"The Goethals Bridge Replacement (GBR) spanning the Arthur Kill Waterway between Elizabeth, NJ and Staten Island, NY consists of a dual-span 1,982.5-ft long cable-stayed bridge with approach spans of 2,545 ft on the NJ side and 2,788 ft on the NY side. The bridge is supported on over 200 drilled shaft foundations ranging in diameter from 4.5 ft to 10 ft and socketed into Passaic Formation siltstone. Drilled shaft resistances for design were based on load tests as described in a companion paper (Dapp et al. 2016). This paper presents the main foundation design considerations and challenges. The approach to construction of the rock sockets, with a focus on quality in order to support the use of high nominal values of side and base resistance, is described. Lessons learned from this project and their application to future similar projects are presented.INTRODUCTION AND BACKGROUNDThe Goethals Bridge Replacement (GBR) project is a Public-Private Partnership (P3) that represents a major milestone for the Port Authority of New York and New Jersey (PANYNJ) in its distinguished history of bridge building in the greater New York City metropolitan area. The new bridge will replace the existing Goethals Bridge, named after Major General George W. Goethals, Chief Engineer of the Panama Canal and the first consulting engineer for the Port Authority. The existing Goethals Bridge along with the Outerbridge Crossing and the Bayonne Bridge comprise the three Port Authority bridges connecting Staten Island with New Jersey. The existing Goethals Bridge and the Outerbridge Crossing are cantilever truss structures and both opened on the same day in 1928. They were designed by J.A.L. Waddell under the supervision of the eminent engineer Othmar H. Ammann (1879-1965), who was the designer of many other iconic bridges in the NY City area including the Bayonne Bridge (1931), the George Washington Bridge (1931), and the Verrazano Narrows Bridge (1964). The designer of record for the replacement Goethals Bridge is Parsons Corporation, which is the successor firm of Robinson & Steinman, whose principal David B. Steinman was also a notable NY area bridge designer and a contemporary and rival of O.H. Ammann.The replacement Goethals Bridge is supported on over 200 rock-socketed drilled shaft foundations. Each main pylon tower is supported on a group of six 9-ft diameter drilled shafts and each anchor pier is supported by two 10-ft diameter shafts. Each approach pier consists of a two-column bent with each column supported on a rock-socketed drilled shaft. A rendering of the Main Bridge crossing the Arthur Kill is shown in Fig. 1."

Jan 1, 2016

By Sudip Basack

"The topic of pile foundation subjected to lateral cyclic load is an age-old problem confronted by Geotechnical Engineers. The environment prevalent in ocean and shorelines necessitates the piles supporting offshore and onshore structures to be designed accounting for the lateral cyclic loading resulting from the effects of sea waves. The quasi-static nature of this type of loading induces remarkable deterioration in the interactive performance of the soil-pile system. This can be manifested as progressive loss in pile capacity associated with increased pile head deflection. The work reported herein is aimed towards conducting rigorous theoretical analysis using finite difference technique so as to analyze the lateral cyclic loading response of a single, vertical pile embedded in cohesionless soil. The theoretical results are compared with the experimental results and reasonably good agreement is noted. This paper presents a brief description of the theoretical analysis carried out with some typical results and the relevant conclusions drawn therefrom. 1. INTRODUCTIONOffshore structures, namely, quay & harbour structures, jetties, tension leg platforms, oil drilling platforms, etc. are largely supported on pile foundations. Apart from usual loads from superstructures, these piles are subjected to continuous action of wave loading. This type of lateral loading is quasi-static cyclic in nature which results in considerable degradation in the interactive performance of the pile-soil system initiating progressive reduction in pile capacity associated with increased pile-soil stiffness. This may ultimately lead to disastrous consequences.Amongst limited research works in this field, the major contributions are made by Matlock (1970), Idriss et al (1978), Poulos (1982), Vucetic et al (1988), Long & Venneste (1994) and Basack (1999). A brief review of these works indicates that the degradation of the pile-soil system under lateral cyclic loading mainly depends upon the following parameters: number of cycles, frequency (cycles per unit time), cyclic load level (ratio of cyclic load amplitude to the lateral static ultimate pile capacity, in case of loadcontrolled mode) and cyclic displacement level (ratio of cyclic displacement amplitude applied at the pile head to the external pile diameter, in case of displacement-controlled mode). As pointed out by Poulos (1981 & 1982), the degradation is mainly due to: 1) partial to zero dissipation of excess pore water pressure generated during cyclic loading in progress, 2) destruction of interparticle bond with particle realignment and 3) rearrangement and gradual accumulation of permanent plastic deformation around pile"

Jan 1, 2005

By Jorj O. Osterberg

This paper is for presentation at the 14th Annual Members Conference of the Deep Foundations Institute held at the Hyatt Regency Hotel, Baltimore Maryland on October 10, 1989. This is an introductory presentation of a one hour symposium on the applications of a new testing device. This paper discusses how the device works and its uses. Papers following this describe: - How the cell is constructed and calibrated - Two projects on which the device was used on long driven piles to determine the frictional capacity - A bridge project on which the device was used on an instrumented test drilled shaft and a working drilled shaft

Jan 1, 1989

By Bengt H. Fellenius

.1.1 Prior to commencement of pile installation operation, submit to [Engineer] for [approval] [review], details of equipment for installation of piles. SPEC NOTE: The information requested in 3.1 .1.2 is necessary as input to a detailed wave equation analysis of the pile driving. .1.2 For impact hammers, give manufacturer's name, type, maximum rated energy and rated energy per blow at normal working rate during easy and at termination driving, mass of striking parts of hammer, mass of driving cap, and type and elastic properties of hammer cushion. .1.3 For non-impact methods of installation, such as drilling, jacking, jetting, use of vibratory hammers, or other means, give full details of characteristics necessary to evaluate performance. .2 Impact Hammer SPEC NOTE: Do not exclude a hammer type unless for very specific reason. .2.1 [Drop hammers will not be permitted.] [Diesel hammers will not be permitted.] For final driving of [TYPE] piles, provide a hammer capable of delivering to the pile a non-erratic impact stress not smaller than [VALUE] Pascal and transferring a non-erratic energy not smaller than [VALUE] Joules per blow to the pile head at normal working rate.

Jan 1, 1991

By John C. Niedzielski

The PHX Sky Train is a five mile long automated people mover system located at Phoenix Sky Harbor International Airport. Phase I of the PHX Sky Train includes the design and construction of 227 drilled shafts supporting three stations and approximately 9,000 feet of elevated guideway. The guideway includes a 100 foot high, 330 foot long span extending over an active taxiway, which will be the first system of this kind over an active taxiway in the world. The soil conditions in this area generally consist of alluvial Sand, Gravel and Cobbles (locally known as SGC) deposited by the nearby Salt River. The foundation system will support relatively high axial loads, lateral loads and moments due to the height of the guideway above the ground surface, where it needs to pass over existing concourse walkways, bridges, a taxiway and buildings. Drilled shaft design involves designing 4.5-foot to 9-foot diameter drilled shafts within the SGC deposits, most of which extend well below the groundwater table. There is a high potential for collapse of drilled shaft excavation sidewalls within this material. Such extreme design loading conditions, together with difficult ground conditions at the site, result in several challenges for the design and construction of the deep foundation system for the guideway and stations. A load test shaft was designed and constructed as a means to provide site-specific measurement of axial performance under these difficult conditions. Results from the load test were used to reduce the size of the drilled shafts. This paper provides an overall description of the PHX Sky Train project, a summary of the ground conditions, design requirements, load test results and construction methods and equipment used to successfully install the drilled shafts for this project.

Jan 1, 2010

By Craig H. Olson

"Anew ship dock at a Philadelphia area refinery will be capable of docking the largest tanker to travel the Delaware River, the Stena V-MAX, which will induce significant lateral loads. The loads at the dock, a system of mooring dolphins and platforms, will be resisted by over 150 pipe piles, including some 20- and 30-in diameter, reinforced, concrete-filled pipe piles and H-piles. Construction included driving the pipe piles to the required ultimate capacity, flushing the pipe pile casing clean of overburden materials, followed by drilling rock sockets into the underlying Wissahickon Formation. The Wissahickon Formation is a complex subsurface that includes variations in depth to bedrock, rock quality, degree of weathering and the presence of very hard quartzite lenses or inclusions. Because of the problematic subsurface, the designers and client requested extensive pile dynamic analysis (PDA) testing by TRC Engineers (TRC).Before beginning, the contractor requested that TRC perform the WEAP (wave equation analysis program) to evaluate the proposed hammer (APE D30-32 open-end diesel) to drive the piles into the proposed bearing strata while maintaining allowable compression stress levels. The WEAP provided a prediction of blow counts and stresses for various ultimate capacities, and showed that for the HP14x89 piles with a required ultimate capacity of 480 kips, a blow count of at least four blows per in at a stroke of 8.0 ft was necessary. New Approachway RampThe PDA testing began at the new dock approach way ramp, parallel to the existing one. The new structure is a 300-ft-long by 21- ft-wide concrete deck supported on seven bents; each has two 24- ft-diameter steel open-ended pipe piles. Every pipe received an HP 14 x 89 x 80-ft pile that was later driven beyond the pipe pile tip to create a composite pile. The pipe piles were later cleaned of overburden materials and finally filled with concrete and rebar. At each bent, a cap was installed on top of each pair of pipe piles, and then a prefabricated concrete deck was added."

Jan 1, 2008

By Dan Brown

Improvements in construction equipment and techniques in recent years have made possible the use of drilled shaft foundations in diameters and lengths not previously considered practical or feasible. Many highway bridge and other structures are now routinely founded on drilled shafts which -are 8 to 12 feet in diameter and extending over 200 feet in depth below grade. There are unique challenges associated with constructing such large and deep cast-In-place foundations and engineers should be aware of the special needs associated with site investigation, construction specifications, material requirements, and quality assurance. This paper outlines a number of special considerations for these foundations, along with strategies that may be employed to improve the reliability and quality of large drilled shaft foundations.

May 11, 2007

By Andrew Rietz, Yu Bao, Steven Halewski

"HP-Pile foundations are the most favorable type of foundations for bridges because of their constructability, versatility with regard to subsoil conditions, and settlement controllability. For many years, bridge engineers have puzzled over the most economical way to orient HP-Piles: Should the strong axis be oriented in the longitudinal direction or in the transverse direction? The accurate design of foundations may considerably reduce construction costs. In order to answer this question, 3-D finite element models will be set up to analyze the effects of pile orientation on bridge behavior. Because seismic loading usually controls the structural design in seismic zones, it is important to investigate the effects of pile orientation under such loading. HP-Piles are designed conservatively due to the uncertainty of the dynamic soil-structure interaction during earthquakes. For the bridge substructure, the soil’s stiffness plays an important role in load distribution as the soil and piles act as a combined system to resist the seismic loading. The dynamic soil-structure interaction mechanisms of bridges in both the longitudinal and the transverse directions will be investigated through the use of 3-D finite element models. The numerical models will realistically simulate the soil-pileabutment- wingwall-superstructure system subjected to seismic loads. Nonlinear soil springs will be employed to model the non-elastic soil behavior. The analysis will provide theoretical support to the design practice.IntroductionAs sustainability has asserted itself in the public’s eye, bridge professionals have rushed to develop criteria for sustainable bridges. The three main categories that define and distinguish sustainable bridges are: lower energy input, increased durability, and simplified deconstruction. By optimizing the structural members, the engineer is able to reduce the material quantities for the bridge, effectively reducing the energy input for the bridge (Hunt; Whittemore). A deeper understanding of soilfoundation- structure mechanism will facilitate sustainable bridge design by lowering energy input and increasing the service life of bridges (Rietz et al.)."

Jan 1, 2017

By Allen B. Stanton, Parthiv Brahmbhatt, Michael Grimm, Stanley L. Worst

Constructing a circular shaft consisting of secant piles has its own complications which make it more difficult than typical drilled shaft construction. Add to that performing under low overhead powerlines and sitting inside of a 40-foot deep, 50-foot diameter shaft and it becomes more about logistics than the actual drilling. The complexities associated with the Romeo Arm Interceptor Segment 5 Lining project are the focus of this paper, delving into the details that made it work successfully.

Oct 1, 2022

By K Ilamparuthi, R. K. Madhumathi

"This paper presents the results of 1g model tests conducted on model piles both single and two pile groups embedded in sand by physically inducing lateral soil movement. From the test results it was found that the pile with higher L/D ratio exhibits higher deflection in case of pile embedded in medium dense sand whereas in loose sand the response is vice versa with higher deflection for the pile of lesser L/D ratio. The induced bending moment in piles is more for longer piles than shorter piles irrespective of the density of sand bed. It is also found that the pile head deflection and the bending moment are found to decrease exponentially with increasing distance between the pile and the wall. For pile group arranged in a row parallel and perpendicular to retaining wall, the deflection of single pile is more than the deflection of two pile group irrespective of the depth of excavation for spacing of piles tested. The influence of soil movement on the lateral response of pile is also analyzed through 3-dimensional finite element analysis. The numerical results thus obtained are validated with the results of experiments. The Mohr-Coulomb material model adopted to represent the soil behaviour predicts the response of pile reasonably and compares well with the experimentally observed response.INTRODUCTIONPile foundations are adopted to support structures such as foundations of high rise buildings, transmission towers, offshore platforms, bridge abutments etc., when good bearing stratum is not present at shallow depth to bear the loads of these structures. In the recent past particularly in the urbanized areas structures are built close to one another and nearby excavation will cause a reduction of lateral earth pressure and soil movement behind the retaining wall (Ong, 2004). The reduction in support stress will induce additional movement to the pile and leading to distress in pile foundations located adjacent to supported excavation. In these situations understanding the response of piles next to supported excavations becomes essential.The behavior of piles subjected to soil movement was studied by Poulos and Chen (1996 and1997) through tests on 1g models and the findings concluded that the maximum bending moment was found to decrease with decreasing pile diameter and decreasing pile spacing . Leung et al. (2000 and 2003) studied the effects of excavation induced soil movement on pile foundations in sand through centrifuge tests and established that the restraints on the pile head would cause additional shear force and/or bending moment at the pile head, although the restraints help to reduce the pile head deflection/rotation. In the theoretical studies of Poulos & Chen (1997), boundary element method (PALLAS) was used for analysing the pile subjected to lateral soil movement and charts were proposed for designing the piles. Pan et al. (2002) and Miao et al. (2006) analysed the passive pile behavior through three dimensional finite element analyses. However research works reported on piles subjected to lateral soil movement are limited."

Jan 1, 2015

By John Mould, Gordon Chen, Michael Oakland, William McElwee

"This paper will discuss the design analysis of sheet pile cofferdams for static and dynamic blast loads. Following construction of the new Willis Avenue Bridge across the East River between Brooklyn and Manhattan, in-river piers No. 9 and No. 10 from the former bridge were demolished, partially by explosive charges. The blast at Pier 10 was conducted first and though the demolition charge was relatively small, it gave confidence that the sheeting could be designed to resist the blast load. This paper primarily summarizes our analysis and performance of a sheet pile cofferdam at Pier 9 used to withstand the larger blast loads, contain the blast debris, and allow excavation of the pier below the existing river bed mudline. The program NLFlex was used to predict stresses and deformations of the cofferdams under dynamic blast loads, using simplified equations to estimate the underwater blast pressures. Specifically, the analysis focused on the stresses in the struts, waler beam, sheet pile interlocks and connection of the sheeting to the waler beam. Design included allowing plastic deformations and limited rupture of the sheet pile interlocks under the blast loading. Comparisons are made between stresses assessed by the dynamic finite element modeling and empirical relationships used within the industry. The performance of the system after the actual blast is discussed as well as details of the performance of welded vs. bolted connections within the system. IntroductionThe Willis Avenue Bridge is one of the major access ways from the Bronx into Manhattan. The location is shown on Figure 1. The original bridge constructed in 1901 was a swing bridge over the East River. The bridge was in disrepair and outdated with regards to its ability to handle the flow of traffic resulting in numerousaccidents.In 2007, Kiewit Constructors Inc./Weeks Marine, Inc., A Joint Venture was selected to construct a replacement bridge. The $612 million project included construction of a new bridge just to the south of the original bridge. The most notable aspect of the construction was floating and lifting the new 350 ft. long swing span in place as a single piece. However, another significant challenge was using blasting to demolish two of the abandoned piers which were within the East River. The blast would be near existing structures in both Manhattan and Brooklyn and would be within 30 ft. of the new bridge."

Jan 1, 2017

By Arash Saeidi Rashk Olia, Dunja Perić

The increasing demand for renewable energy has attracted attention to energy geostructures as means of extracting clean geothermal energy from the ground. To further advance the understanding of soilstructure interaction in energy piles analytical solutions considering the self-weight of the pile were derived. These solutions were then incorporated in recently-derived thermomechanical weightless solutions to provide comprehensive analytical solutions for axial displacement, strain and stress in single energy piles. This was accomplished by comparing responses of energy pile under different loading scenarios that reflect presence and absence of the self-weight. Results of mechanics-based analysis revealed that the self-weight of energy piles embedded in stiff soils has no significant contribution to displacement, strain and stress that develop under thermo-mechanical loads. Overall, the significance of the self-weight contribution depends on the magnitude of thermal load as well as the soil-pile interface stiffness. The stiffness of end restraints imposed to the pile head and tip were also found to play an important role in contribution of self-weight in induced thermomechanical stresses in energy piles.

Oct 1, 2022

By Mark D. Fuhriman, Parham Khoshkbari, Robert Fosse

Drilled displacement piles are becoming an increasingly common deep foundation choice for their relatively simple installation methods, applicability to a wide range of subsurface conditions, and versatility. The installation method includes drilling and displacement of the soil followed by delivery of fluid cement grout under pressure, and placement of steel reinforcing to complete the pile. Because the installation method uses blind processes that do not permit direct observation of the pile, it is desirable to employ redundant testing tools to complement good construction techniques and inspection practices to ensure integrity of the piles. This paper examines the use of a range of integrity testing tools used for pile installations at a major office campus development. Because the integrity of a drilled displacement pile and its performance depend to a large extent on the skill and experience of the installation crew, the paper explores how use of multiple practical tools, including automated monitoring tools on the pile installation equipment, thermal integrity profiling, and high-strain dynamic testing, ensure structural integrity of the completed piles and how redundant integrity testing methods complement good construction and inspection practices add confidence in the quality of the foundation system.

Sep 8, 2021