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By R. Lee Wooten, David R. Shields, Darren D. Clark

"Borehole permeability tests that measure flow or head changes in boreholes located within seepage barrier walls are commonly used to estimate the in situ permeabilities of those walls for quality control and assurance. The current state of practice for estimating permeabilities from these barrier wall borehole tests is to use equations published by M. J. Hvorslev in 1951. Hvorslev’s borehole test equations model an infinite stratum of uniform permeability, which is not the actual condition for a test performed in a low permeability barrier wall located within a high permeability stratum. We examine and develop alternative equations based on line source analytical models, which more closely match barrier wall test conditions. We describe how these alternate equations can be used to estimate barrier wall permeabilities from borehole tests and compare the results to those obtained from the Hvorslev models. We also provide recommendations that consider differing upstream and downstream water levels.Barrier Wall Permeability Tests - State Of PracticeThe installation of seepage barrier walls has become more common in a variety of applications ranging from dams and levees to contaminated sites requiring retardation of groundwater flow. The types of seepage barrier walls and installation methods include soil-bentonite, soil-cement-bentonite, concrete, self-hardening slurry, geomembranes, and sheet piles, installed with various soil mixing, slurry-supported trench, and driving methods.Owners and contractors have used a variety of methods to evaluate the permeability of these seepage barriers. The following table lists commonly used quality control/assurance tests for evaluating the permeability of a seepage barrier."

Jan 1, 2016

By Bernard B. Vannoy, Howard W. Gault, Ramesh Bobba

"Treviicos-Soletanche Joint Venture (JV) and the US Army Corps of Engineers (USACE) have installed a 3800-foot long, 275-foot deep and minimum 2-foot wide secant pile barrier wall at Wolf Creek Dam in Jamestown, KY. This paper describes the methodology employed by the JV and USACE to evaluate the overlap, thickness, and position of the barrier wall. It addresses the contractual requirements, positional uncertainty, and evaluation procedures.These procedures evolved over the course of the project as various issues were identified and procedures developed to evaluate these issues. During the project, it became clear that the JV and USACE could ascertain that the wall thickness and overlap requirements could be met if the overlap based upon Koden data was at least 0.7’ in the left-right direction. For a small number of piles with overlaps between 0.5’ and 0.7’, the piles are contractually compliant yet contain a minor degree of uncertainty in the overlap. Initially, the USACE assumption was that the amount of uncertainty of verticality measurements would require more than a 1-foot measured overlap in the left-right direction to confirm an actual, contractual 6-inch overlap. With time and experience, the limit of measured overlap was reduced in accordance with greater understanding of the equipment capabilities and tolerances. Other lessons learned include the need for Quality Control/Assurance personnel to collect data at the same starting point for every pile.For every pile the JV and USACE compared analog and digital data to provide confidence that the correct digital data was used for overlap calculations. Perhaps the most important lesson learned was the importance of the JV and USACE working together and sharing all data. Overlap analysis was performed by the JV’s Barrier Wall Specialist and a small number of USACE personnel. This resulted in a high level of experience and expertise within a small group.IntroductionThe Treviicos-Soletanche Joint Venture (JV) and the US Army Corps of Engineers (USACE) have installed a 3800-foot long, 275-foot deep, and minimum 2-foot wide secant pile barrier wall at Wolf Creek Dam in Jamestown, KY. The wall was installed through a 6-foot wide Protective Concrete Embankment Wall (PCEW) which was installed two feet into rock. The PCEW protects the embankment from erosion of drilling fluids during subsequent operations. Below the PCEW the piles were installed to a specified elevation (staggered at 475’ and 473’ below the 748.2’ work platform). The Ordovician limestone and shale bedrock is flat lying with few vertical fractures. These conditions facilitate the advancement of pilot holes with very low deviations (with considerable credit to the JV’s drillers and steering engineers). The pilot holes were spaced on 31.5-inch and 35-inch spacing. Subsequent enlargement of the pilot holes to 50’ resulted in a continuous wall. This paper addresses the requirements and procedures to assure that the wall was as wide, deep and continuous as specified."

Jan 1, 2015

"Premissas BásicasCaracterísticas do concreto centrifugado(Spun concrete characteristics)Aplicação em obras de engenharia de fundações(Application engineering works foundations)Logística de fabricação e transporte(Manufacturing logistics and transportation)Emendas x uso de aplicação(Amendments x use application)Geologia brasileira, da região costeira a presença de grandes bolsões de argila mole(Brazilian geology, coastal region the presence of large pockets of soft clay)Influencia do sistema de cravação(Influence of driving system)Transferência da Energia Aplicada(Applied Energy Transfer)Estacas longas(long piles)Controles executivos (diagrama de golpes, nega, repique elástico, ensaios de carregamentodinâmico, provas de carga).(Executive Controls (blows diagram, sets, elastic rebound, dynamic load tests, load tests).)ECD – aplicação da metodologia do DIETECD - application of the methodology DIETBrazil has a highly variable geology all along its coast that directly influence the choose of foundation type, being too employed the use of reinforced spun concrete piles initially ranged in diameter from 60 to 80 cm. Over the past 10 years with the advent of investment in marine works projects began to demand a new range of piles with diameters greater than 100 cm and in the absence of amendments.On land is also very remarkable the presence of regions with large layers of soft clay, in prime areas that have been explored. A classic example is the Barra da Tijuca in Rio de Janeiro that has suffered from the housing boom growing toward these regions. In these regions it has been very common driven lengths of about 40.0 meters, which basically go through thick layers of soft material or unconsolidated and they will find strength in depth with residual soil layers or even the bedrock.The spun concrete has great qualities for application in deep cuttings resulting from the production process, which gives a redistribution of fresh concrete mass collaborating with the particle size distribution effective loss of water that is thrown to the center stake being subsequently discarded. Consequently this contributes to a reduction in the factor a/c that is directly connected to increase strength.The fact that there is a sort of concrete helps to reduce voids in the mixture, which increases the durability characteristics. This condition made it possible to employ the spin technique on poles, which are directly linked to aggressive media in large urban centers.Another very attractive feature is that the centrifuge process can work with concrete with the lowest percentage of mortar and more gravel. This concrete mix directly contributes to increasing the specific modulus of elasticity, thus allowing a greater capacity to absorb the energy of the blows transferred with less deformation.Despite the great potential of land application of prefabricated spun concrete stakes there are only three factories and its limitation is the cost of transporting manufactured for the various regions, since all transportation is done by road.For its transportation is carried out exclusively by trucks, this limits the size of cuttings being produced commonly in length from 11.0 to 12.0 meters in length and smaller compositions. For use in long piles of works is resorted to amendments in the form of metal rings, concreted near the ends of the stakes, with the transfer through steel bars in CA-50 welded to the ring. Usually run in steel ASTM A-36. Later in the work these rings are welded with coated electrode.In the case of maritime stakes are very used to drowned splicing technique, which basically consists during the spin process leave one end with the armor of the apparent stake and work together two elements and make specific, with superior resistance to the prefabricated stake.This study in addition to briefly introduce the process of manufacturing, design and logistics presents a detailed study of applicat"

Jan 1, 2015

By Alan Quiroga

Nestled between Meridian Park and Howard University in the heart of Washington, D.C., the historic block between 14th, V and W streets North- west featured several original struc- tures, many of them dating to the 1800s. During its rich history, this square block has been home to a variety of different organizations including automobile showrooms and repair businesses, a parking garage, various industrial warehouses, and, in recent years, the headquarters of the renowned D.C. nonprofit Martha's Table. The revitalization of the buildings in this block also known as the Collection 14 project involved the transformation of aging and historical structures into a new multi-use development. The redevelopment project was distinguished by the retention of period street-facing building facades (to the extent possible) to preserve the character and culture of the historic neighborhood while revitalizing the block with some modern construction elements. The complexity of the project and difficult subsurface conditions required specialized and extensive sheeting, shoring and underpinning work to be performed. This project had many parties involved, including: • • • • Owner: Madison Investments Owner's representative: Compass Design & Development General contractor: McCullough Construction Civil engineer: Vika Capitol Structural engineer: Ehlert Bryan Architect: Perkins Eastman DC Geotechnical engineer: GEI Consultants Sheeting and shoring contractor: Steele Foundation

Aug 1, 2023

By David White

When finished (projected completion in 2016) the Hong Kong-Zhuhai-Macau Bridge Project will comprise three cable-stayed span bridges and a 4.15 mile immersed tube tunnel - linking Hong Kong to Macau and the mainland Chinese city of Zhuhai. The design included two artificial Islands to serve as the transition structures for the tunnel to bridges, entailing a massive seaborne land reclamation project, and the use of thousands of sheet piles, and man-hours. The challenges of driving individual steel sheet in 100? of water are well known, let alone in the open waters of the South China Sea. In 2010 a joint effort between American Piledriving Equipment (APE) and Allnamics Pile Testing Experts convinced the Chinese contractor First Harbor Marine Group China that a massive multi-vibro hammer can be used to drive 130? long, 72? diameter steel pipe piles weighing 662 US tons each into the sea bed of the South China Sea for the Hong Kong - Zhuhai - Macau bridge artificial islands. Combining APE?s hammer design, production and operation know-how with the pile driving simulation and installation know-how of Allnamics made it possible to show the feasibility of driving these gigantic piles into bottom of the sea to the required depth.

By S. P. Lin

The numerical models of nonlinear piles for deep foundations are studied in this paper. The purpose of these is to clarify the mechanical behaviour of deep foundation nonlinear piles subjected to axial and lateral loadings. Based on the site data of p-y curve as well as t-z curve of foundation soils, it is possible to evaluate pile performance under above mentioned loads by means of combined FEM/FDM models. Numerical examples are presented in tall building and offshore jacket for illustrating the technique, it show high efficiency of these models. Some information to be interested by design engineers are given, especially for those who pay very concerns on the interaction behaviours of structure and its pile foundation.

Jan 1, 2010

By M. Y. Xia

In this paper, based on the Theological tests of the interface between clay and concrete, an interface Theological model is proposed and is used in the finite element analysis which takes soil as viscoelastic mass and Theological effect of the interface between diaphram wall and ground into consideration. Its results are compared with those without an interface element, without considering the relative creep displacement. Close attention is paid to the variation of wall with time under the condition of various interface shear stiffness and viscous sliding coefficient, and their effects on the wall bending moment are primarily verified in the paper. The change of wall bending moment with time, trench heave and wall displacement in different excavation depth, bracing position, parameters for soil are also studied.

Jan 1, 2010

By Barry C. Roth

A Real Time Automated Remote Reading Electrolytic Tilt Monitoring System was effectively deployed for monitoring an existing five story brick building during underpinning, shoring and excavation operations for a directly adjacent thirty-foot deep excavation. The monitoring system was comprised of four sets of uniaxial electrolytic tilt meters connected to a Campbell datalogger with multiplexer, cellular modem and solar power. The excavation was for the foundation and underground parking as part of a new 55 story tower complex. Challenges to the contractors and to our monitoring personnel which were addressed included a tight urban site contemplating property line to property line new construction with directly adjacent old existing buildings, buried concrete foundations from former site use, cohesionless pervious sandy soils and high groundwater. Highly variable and diurnal ambient temperature regimes due to adjacent building shadows required careful corroboration and application of temperature corrections to the raw data. Earth tides were suspected on a very small scale and investigated by correlation between the data and the local sinusoidal tidal ephemera. Incidental inadvertent contractor interference with the instruments during underpinning due to site constraints was readily detected.

Jan 1, 2007

By Melissa S. Beauregard, Randall A. Pietersen

This study focuses on quantifying the effects of water infiltration on a full-scale energy pile system’s ability to meet the thermal demand of an HVAC system. Theoretically, an energy pile system should increase its thermal capacity after a rain event due to increased moisture content creating an increase in thermal conductivity of the surrounding soil matrix. The United States Air Force Academy has an energy pile research site consisting of 8 full-scale energy piles located below a shower facility. The local colluvium surrounding the piles allows for relatively high water infiltration during rain events. This study uses an 11kW Precision Geothermal Geocube to apply a thermal load on two single-loop piles. A weather station located south of the structure records atmospheric conditions. Results indicate that moderate rain events can caused up to a 23% increase in the system’s thermal exchange capacity. This change is due to the increase in moisture content near the surface, which penetrates to deeper soil layers with time. The time required for moisture to penetrate to greater depths and then dissipate in the soil matrix, explains why increased system performance is seen for over a week following the passing of a singular rain event. 1 INTRODUCTION With a “future-forward” focus, there is an ever-pressing economic and environmental need to use sustainable sources to meet growing energy needs. HVAC is typically responsible for 34% of the overall energy required by commercial buildings and 48% of the energy required by residential buildings (USEIA, 2009; USEIA, 2012). Energy piles are a low cost, sustainable technology that have been used to offset this energy demand incurred by a building’s space heating and air conditioning requirements. An energy pile consists of heat exchanging elements in a closed loop system integrated into a building foundation and connected to a ground source heat pump (GSHP). It is most common for these heat- exchanging elements to be constructed within a drilled shaft foundation due to both construction practices and geometric considerations. This system operates based on the principle that at a certain depth below ground (typically 4 meters) subterranean temperature remains constant at a value equal to the mean annual air temperature at a given location (Kavanaugh et al., 1997). This allows the soil to function as a heat sink for cooling operations and a heat source for heating operations when exchanged within this zone of relatively constant temperature. For the past 25 years, the implementation of energy pile technology in public, residential, and even large-scale architectural complexes has slowly expanded which has created an increase in research into the topic as a result (Brandl, 2006; Hamada, 2007; Sekine et al., 2007; Gao, 2008; Bourne-Webb, 2009; Stewart and McCartney, 2013; Murphy et al., 2014). When pile construction takes place beneath the groundwater table, soil is under fully saturated conditions, maximizing thermal exchange for a GSHP system. Under unsaturated conditions, however, changing moisture contents change thermal conductivity values in a soil, which affect a GSHP system’s ability to meet a thermal demand. The observational data presented in this paper apply to GSHP systems in unsaturated soil conditions.

Jan 1, 2019

By Khamis Y. Haramy

Curing temperature, density, and moisture significantly affect the velocity measured in the crosshole sonic logging, the rate of strength gain, and the final strength of concrete in drilled shafts and, thereby, affect their structure capacities. Non-destructive field measurements can enhance the QA/QC program by measuring temperature, density, moisture, and sonic velocity of curing concrete during the construction and curing of drilled shafts. The curing environment can greatly affect the concrete strength, and requires close attention during construction. This article shares the experience with the NDE technology used in the QA/QC program in the drilled shaft construction. To understand the mechanism by which a drilled shaft cures under field conditions, two newly constructed drilled shafts were monitored for up to seven days, immediately following concrete placement using the following geophysical logging methods: a) temperature logging; b) crosshole sonic logging; c) gamma-gamma density logging; and d) neutron-moisture logging. One additional drilled shaft was also monitored to a shorter duration. Temperatures were monitored using the sensor in access tubes and/or thermocouples embedded at the center of a drilled shaft and near its reinforcing cage. For a small shaft under 1m diameter, curing temperatures appeared to peak at 41° ? 68° C at different depths at around 24-hour curing time and decreased to and stabilized at around 23° ? 35° C in 6 days. The shaft curing rate varied with depth, shaft diameter, surrounding geo-material types, and the depth of ground water. CSL logging was performed in one shaft from top to bottom from six access tubes and limited monitoring in another shaft. The velocity increased with curing time till 4 to 7 days, and, at a specific time, the velocity appeared to be inversely correlated to curing temperatures. The gamma-gamma density log (GDL) results from 5 different depths were obtained at a source-detector separation of 355 mm. The average density was found to increase with curing time, but decrease slightly in 3 to 5 days. At a given time the GDL density curves seemed to correlate with the neutron monitoring logging (NML) moisture curve. The NML moisture was monitored from 1st to 6th day after concrete placement. The moisture was highest when surrounded by bedrock, then clay, and sand due to different hydration rates.

Jan 1, 2007

By Kanagarajah Ravishankar

Drilled shaft (caisson) foundations are extensively used in the past. In the central part of New Jersey, the soils consist of silt and clayey silt overlying Triassic age shale bedrock. The shale is friable and generally severely weathered and highly fractured. The shale crumbles readily into small fragments. In general, the shale is encountered in shallow depth. Subsurface investigations indicated that the upper part of the shale is very soft, highly weathered, and able to advance through soil exploration methods. The underlain formation is relatively hard and required rock coring techniques for sapling. Individual core recoveries ranged from 10 to 100 percent and Rock Quality Designations (RQD) vary from 0 to 90 percent. Although several methods available to estimate the axial capacity of drilled shafts, it is a difficult task for the designer choose the suitable method due to self disintegrate nature of the shale. In the recent years several bridge foundations have been constructed using drilled shafts founded on shale rock in the vicinity of the central New Jersey. Based on load tests carried out on drilled shafts during construction, subsurface exploration, and laboratory tests, suitable methods for determining axial capacity of drilled shafts is analyzed. This paper presents the findings of the field tests and suitable methods to determine the axial capacity of drilled shaft founded on soft shale. Key words: Drilled shaft, axial capacity, Osterberg load test, shale.

Jan 1, 2006

By Michael Arnold, Jignyash Manyam, Yoav Rappaport

The USACE required construction of over 13 miles of cutoff wall at an average depth of 65 feet for the Herbert Hoover Dike (HHD). To meet project requirements, to provide quality control and make sound operational decisions, automated data capture, retention and visualization is crucial. Accurate and complete data management allows the authors to deliver critical business insights and to improve operational efficiencies. The author’s understood the necessity of capturing all their data, and efficiently processing and displaying it for multiple stake holders, for both internal and external purposes. The authors realized early in the project life cycle that data ownership and management is one of the fundamental features of the construction process. The authors developed their own software and use two in house applications; WEB-BGM online portal and, b-project which store rig production information combined with field quality control. b-project is used to create and deliver the Enterprise Database (EDB) to the USACE. Another biproduct of capturing the production data is the generation of the Geographic Information Systems (GIS) and also business analytics visual interactive display, developed through Microsoft Power BI. The paper focuses on the business process workflow and various technologies employed and lessons learned from the field operator perspective to achieve higher returns on business software operations.

Oct 1, 2022

By Jørn Thomsen, Christoffer Brodbaek

"As governments increasingly accord high priority to sustainable energy, policymakers are finding that wind energy has a long track record as a proven alternative to conventional energy supply.Over the past two decades, wind turbine projects have been constructed offshore because of more stable offshore wind conditions and because there is more available space for large wind farms out in the open sea. Vindeby Wind Farm in southern Denmark was constructed in 1991. As the world’s first offshore wind farm, it provided valuable information and experience for researchers and designers that have led to new technologies and design improvements, a trend that will continue as more offshore wind farms are constructed. Today, the world’s capacity of the installed offshore wind turbines exceeds 1,000 MW. Most of these are installed in Northern Europe where there was early political support and favorable conditions, such as strong winds and relatively shallow waters. Offshore wind projects are now under development around the globe, including continental Europe, the U.K. and North America. ‘The largest offshore wind farm today is Denmark’s Nysted Offshore Wind Farm, which has a total capacity of approximately 480,000 MWh, equivalent to the yearly consumption of 120,000 households. It is five to six miles offshore in the Baltic Sea in the southern part of Denmark.The owner is a joint venture between DONG Energy of Denmark and E.ON Sweden. Bonus Energy (now Siemens) supplied the wind turbines, and P. Aarsleff A/S and subcontractors supplied the foundations. The contractor’s consultant, COWI A/S of Denmark, developed and designed the turbine foundations. With a total capacity of 165.6 MW, the project consists of 72 Bonus 2.3 MW turbines in water depths up to 33 ft. The turbines have a hub height of 226 ft, and the turbine blade diameter is 270 ft. The rotor and nacelle (the structure that houses the generator, gearbox and other equipment) weigh approximately 150 tons, and the weight of the steel tower is approximately 130 tons. The wind farm site is located in a relatively protected area of the Baltic Sea, but during the winter months, the water often freezes and the foundations needed to be constructed to resist ice forces. The founding soils at the site are overconsolidated clay tills with boulders and with a thin layer of softer surface sediments. Pockets of up to 30 ft of soft sediments were encountered, which required special foundation preparations."

Jan 1, 2009

By Joseph A. Sopko

The first documented procedures for designing frozen earth structures are over 50 years old, implemented long before the introduction of the Finite Element Method (FEM). Since that time, the development of three-dimensional models has made the traditional and often over-conservative methods relatively obsolete. This paper discusses a new approach that is largely dependent on the analysis of internal stresses with the frozen structure and comparison to frozen soil laboratory tests. A specific design process is discussed related to initial field investigation, laboratory testing, structural and thermal analysis, and performance monitoring. The design results are compared to case histories in the field that verify the procedure. BACKGROUND One of the first documented methods to designing frozen earth retaining structures was by Sangar (1968). Methodical refinements were published by (Harris 1995) and published by the International Symposium on Ground Freezing in 2002 (Andersland et al. 1991). The structural design or thickness of the frozen mass was based on the unconfined compressive strength of the frozen soils. Two simple equations for determining the thickness of a frozen shaft are shown in Fig. 1 and the first two equations below.

Jan 1, 2019

By John Kvinsland

"The Block 43 Project is the future home of the Paul Allen Institute for Brain Science located just off the southern shore of Lake Union in Seattle, Wash. The South Lake Union (SLU) district experienced considerable development over the last 10 years and Vulcan, Inc., which is headquartered in Seattle, is at the forefront of this transition. Once a light industrial/residential location, SLU has transformed into a hub of medical technology comprising new residential units and mixed-use buildings. Malcolm Drilling Company, Inc. constructed four shoring projects for Vulcan in this vicinity over the last year, beginning with Vulcan Block 44, which consisted of 42,000 sq ft (3,902 sq m) of soldier pile and tieback wall to support a below-grade parking facility. Block 44 construction began in February 2013 and ended in mid-April. The feature project, Vulcan Block 43, was in planning stages at the time and began construction in late fall 2013.Awarded by GLY Construction of Bellevue, Wash., in September 2013, Block 43 was the most complex of the block projects performed by Malcolm. Block 43 featured dewatering and ground improvement components along with a water-tight secant pile wall. Following the commencement of Block 43, Malcolm also began work on Vulcan Block 52 in December 2013. Block 52 consisted of 43,000 sq ft (3,995 sq m) of conventional shoring in conjunction with dewatering of 8 ft (2.4 m) of excavation located below the water table. The final Vulcan project was Block 45, which started in January 2014 for Turner Construction of Seattle and consisted of 41,000 sq ft (3,809 sq m) of conventional shoring and required dewatering to complete the final 15 ft (4.6 m) of excavation.Scope and Subsurface ConditionsBlock 43 involved a wide variety of drilling applications for the building to be constructed and properly founded. The primary scope of work involved shoring support for an underground parking structure requiring excavation of approximately 82,000 cu 3 yds (62,694 m ) of soil. The cuts for the excavation were up to 43 ft (13.1 m) in depth, and the excavation was bounded by city streets as well as the South Lake Union Light Rail on its perimeter. In order to excavate beneath the water table, an extensive, deep dewatering system was required to drain the upper fill and reduce the impact of the pressurized aquifer located beneath the excavation. In addition, drilled rigid inclusions, along with compaction grouting, were required for foundation support of the future structure."

Jan 1, 2014

By George Piscsalko

Quality control of drilled shafts and ACIP piles is greatly dependent upon the practices of the site personnel. In many applications it is difficult to properly inspect the shaft prior to concreting, such as when the shaft is drilled under slurry. In other cases, such as ACIP piles, it is impossible to inspect the shaft in any manner prior to concreting. There are numerous methods currently available to assess the integrity of drilled shafts and ACIP piles. Each method has its advantages and limitations. This paper will compare the various available methods as well as introduce a new method for assessing integrity in drilled shafts and ACIP piles. This new method, known as Thermal Integrity Profiling, determines the integrity over 100% of the shaft both inside and outside the reinforcing cage by measuring the hydration temperature of the concrete along the length of the shaft. These temperature measurements can be made by either passing a thermal probe through a standard Cross Hole access tube typically 12 to 48 hours after concrete placement, or from embedding thermal wires within the shaft prior to concrete placement and monitoring them with unattended data collectors for 12 to 48 hours after concrete placement. This Thermal Integrity Profile method will be described in detail and several case histories will be presented. Additional testing methods which will be compared include low strain Pile Integrity Testing, and Cross Hole Sonic Logging. Advantages and limitations for each method will be discussed.

By Dharmil Patel, Michael J. Chow

"Construction progress is nearing completion at a Brownfield Site for a 100,000sf mixed-use 10 story building plus cellar for Silver Star Motors including a two-floor pre-owned Mercedes Benz showroom; high-end residential rental studios, 1, 2, and 3 bedroom apartments; and penthouses on the upper two floors. Excavation through impacted soil extended to 15ft depth. Project is approximately 7 ft north of a NYCT subway station, portions of the SOE are within inches of a 6ft diameter NYCDEP Sewer, and cellar extends below the depth of adjacent structures, requiring over 200 lf of underpinning.A complex series of earth retention systems was utilized consisting of underpinning, drilled-in soldier piles (micro-piles), timber/concrete lagging, soil anchors and inclined rakers supported by a partially constructed foundation mat. Foundation mat subgrade was approximately 4 ft below the groundwater level creating more challenges during underpinning and achieving suitable foundation subgrades. All construction was undertaken on a non-union basis.This paper describes the design, construction, and lessons learned for the multiple earth retention systems, Brownfield Remediation requirements, instrumentation, and monitoring used to manage complications of building adjacent to an active subway station, in close proximity to existing utilities, with underpinning and mat foundation installation below the water table.Results of the instrumentation program are summarized which utilized an AMTS, monitoring prisms on adjacent structures, automated seismographs, and manual NYCT surveys."

Jan 1, 2016

By Pawan L. Sethi

Design and construction of deep foundations and basements is increasingly becoming more complex, as the density and frequency of urban development increases. This growth brings various associated challenges in the form of design considerations and construction challenges. This paper discusses some of the challenges routinely encountered as well as some specific complications in this area, based on author’s experience gained through exposure as specialist contractor (designer), consultant and specialist consultant, along with some information on how these challenges were overcome. The paper highlights some of the key aspects of design coordination and importance of having an awareness of the overall perspective. Examples will be used to illustrate practical problems and the approaches used to respond.

Nov 1, 2022

By Gerry Houlahan

The east span of the 3.5 km long SF-Oakland Bay Bridge is supported by different types of foundations along its span. Starting from the west, its first 460 m section comprising twin concrete box-girders is supported by sands and rock on Yerba Buena Island. A 620 m long steel suspension span then bridges a 25 m deep channel that is formed in sediments overlying rock. Twin concrete box girder structures, each 2.4 km long, complete the stretch over the remainder of San Francisco Bay to the engineered earth fill landing at its east end. For most of its length, the Skyway bridges water 3 to 10 m deep over soft surficial Young Bay Mud. The foundation types include spread footings with hold-downs, steel and concrete piles that are set in drilled rock sockets up to 3 m in diameter and 2.5 m diameter steel tubular piles driven to penetrations of up to 100 m. The design and construction-related considerations are presented. The different foundation types, influences of the site geology and earthquake demands on the substructures are discussed. The seismic motions of the bridge superstructures and substructures, as well as the depth-varying soil motions, influenced the foundation design. Together with performance-based design criteria, including post-earthquake footing displacement limits, these seismic demands influenced various aspects of the foundation design, including the use of battered and vertical piles.

Jan 1, 2013

By Nasr Sheta

"After Hurricane Sandy, the stability of an earth slope in the Atlantic Highlands, New Jersey in the United States was deteriorating due to slumping soils and erosion from flooding. A slope stability evaluation indicated the slope did not satisfy the requirements of the local building code. A triple-tier, pile-supported and mechanically stabilized earth wall was designed and constructed to stabilize the slope. The construction was planned from a 3-m-wide roadway and, because of rough terrain and limited work space at the site, a cast-in-place drilled-pile construction was deemed impractical due to slow pile production. An alternative procedure was utilized by pre-drilling holes, and installing precast tip-and-shaft-grouted (PCTSG) piles, which extended to competent soils to improve slope stability. A grade beam, connecting the PCTSG piles along with soldier beams and concrete lagging were used to form the lowest tier of the slope stabilization, while the middle and higher tiers were built as mechanically stabilized earth. The stability of the proposed stabilization was analyzed using 2-D non-linear finite elements. After construction, monitoring of the wall continued for about 8 months to check its performance, and indicated lateral and vertical wall movements were less than 25 mm and 6 mm, respectively, indicating effective slope stabilization.INTRODUCTIONStabilizing earth slopes using piles to connect near-surface unstable soils to underlying stable ground masses has been investigated by many researchers, who presented various approaches to evaluate the contribution of the pile system towards improving the stability of the slope. Some of these approaches consider the piles as structural elements receiving forces from the upper sliding ground mass and transmitting these forces to the underlying stable one. The force from the top sliding mass is applied at between one third and one half of the pile embedment into the top sliding mass, Anagnostopoulos et al. (1990), Fukuoka (1977) and Matsui et al. (1988). The point of application of the sliding force was explored based on successful case histories while addressing the safety factors for both geotechnical and structural design, Vessely A. et al. (2007). The development of numerical analysis techniques utilizing the method of finite elements (FE) also enabled better analysis and design of slopes stabilized using piles. A FE-based approach was successfully utilized to design slope stabilization with target safety factor based on the shear and bending demands and the spacing of the piles, Pradel D. et al. (2010).After Hurricane Sandy in October 2012, the stability of many properties constructed atop earth slopes located along the coast of the Atlantic Ocean has become a concern due to storm-induced erosion. This paper presents the analysis, design and construction of a hybrid slope stabilization system utilized at one of these storm-impacted properties, which is located in the Atlantic Highlands, New Jersey in the United States. The subject property consisted of a two-story residential dwelling and a parking structure, and was built on top of an about 8-m-high earth slope having crest at about elevation 10 m (el 10) and toe at about el 2."

Jan 1, 1900