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By Hugo Meggitt, Damian R. Siebert, Wystan Carswell

Excavation-induced ground movements are a critical component in the design and construction of deep excavations in urban settings due to the potential adverse effects on adjacent structures and infrastructure. Ground movements are influenced by soil stratigraphy, soil properties, adjacent structures, and construction means and methods. The use of empirical relationships, computer models, and reliance on experience with similar excavations in similar soil conditions often provides a basis for predicting excavation-induced ground movements. In this paper, data from 21 deep excavations approximately 20 ft to 75 ft deep supported by concrete diaphragm “slurry” walls in the Greater Boston area are compared to published literature, considering how different foundation systems (e.g. shallow foundations, caissons, and piles) of abutting structures have been affected by adjacent excavations. The influence of construction method (conventional vs. top-down) on adjacent foundation movements indicate that top-down construction typically results in smaller foundation movements. INTRODUCTION Estimation of ground movements due to excavation is a challenging endeavor, even with complex three- dimensional finite element modeling and high-order constitutive models that are increasingly available in modern engineering practice. Aside from the expense of the soil exploration and testing used to inform these higher-order models, the challenges of modeling past stress history, adjacent structures, and the groundwater conditions during excavation require not only large investments of time during design but also validation from past experience (to avoid a “garbage in, garbage out” paradigm). While site conditions such as soil stratigraphy, soil properties, groundwater conditions, and as-built conditions of adjacent structures can be obtained, measured, and estimated, the effects that means and methods of construction have on ground movements are difficult to quantify. During early phase design, assessments of predicted ground movement are unable to account for all aspects of project construction, nor is it cost-efficient to fully design an excavation while project parameters such as site size and excavation depth are under consideration by the design team. While construction is in progress, benchmarking support of excavation performance and associated ground movements in the context of successfully completed projects allows for a more nuanced view of system performance and provides the opportunity for more informed decision-making (if required) as construction proceeds. For these reasons, the use of empirical relationships and the collection of historical support of excavation performance holds high value for the practicing geotechnical engineer at all phases of the project.

Jan 1, 2019

By Scott Dodds

"The Oxford Hydroelectric Station was a unique project that incorporated a variety of dam strengthening methods to stabilize the facility in order to meet the standards required by Federal Energy Regulatory Commission (FERC). The dam stability and Probable Maximum Flood (PMF) remediation work consisted of (1) construction of a new emergency spillway; (2) installation of 75 high capacity rock anchors; (3) construction of an anchored concrete powerhouse buttress; (4) construction of cast-in-place and sheetpile flood walls; and (5) design and construction of a permanent soil nail wall. INTRODUCTIONThe Oxford Hydroelectric Station is one of 11 hydroelectric facilities owned and operated by Duke Power along the Catawba/Wateree River. The Catawba River originates in the foothills of the Appalachian Mountains just west of Morganton, North Carolina. The river flows east out of the mountains and, at a point just below the Oxford Dam, the Catawba River turns and heads southeast. The Catawba River continues to flow southeast past Charlotte and into South Carolina where it eventually becomes the Wateree River. The Wateree River eventually flows in to the Atlantic Ocean.Located a few miles east of Hickory, North Carolina, the Oxford Dam and Hydroelectric facility is in the upper reach of the Catawba River. Oxford Dam creates the third impoundment along the river known as Lake Hickory. Lake Hickory is well known locally for providing many outdoor activities such as boating, jet skiing, canoeing and fishing. The dam and powerhouse were put into operation in the spring of 1928.Key features of the dam include a short embankment section on the south end of the structure, a 391-foot (119m) long south bulkhead and powerhouse, 540-foot (165m) long gated spillway section and a 235-foot (71.6m) long north bulkhead. The maximum height of the dam is approximately 100-feet (30m) from the crest to the dam/rock interface. (See Figure 1).The work associated with this project is the result of licensing requirements of the Federal Energy Regulatory Commission (FERC) which mandates that all hydroelectric facilities have the capacity to safely discharge runoff created by a critical rainfall event defined as the probable maximum flood (PMF). Duke Power, a division of Duke Energy (DUKE) submitted an initial PMF report in 1992 which indicated that at the Oxford Dam would be overtopped by approximately 10-feet of water during the modeled PMF event. Given the duration and depth of the overtopping, significant damage to the facility and a possible breach could result. Therefore, modifications to the existing facility were necessary to satisfy the report of the PMF model."

Jan 1, 2005

By Chris L. Powell, Russell J. Denny.

"The remotely located Cockatoo Island iron ore mine off the Kimberly coast in Western Australia, which has been in operation since 1951, was recently expanded up to 50m below sea-level using staged construction of a rock-filled seawall around the open cut mining operation. The most recent stage of the seawall expansion required a seepage reducing cut-off barrier to be installed through the seawall into underlying seabed sediments. A line of grout holes at 1m centres was proposed to form the seepage barrier, with grouting extending 17m below the top of the seawall. Top hammer drilling techniques were used to penetrate the 12m deep rockfill to seabed level, and permeation grouting carried out within the rockfill to fill voids and stabilise material around grout holes. The local 10m tides meant that tidal washout of fines and grout would be a major risk, and so a combination of cementitious and chemical grout was used to create rapid gel times. Following permeation grouting, holes were re-opened to allow jet grouting to hydraulically mix and grout permeable seabed sediments below the seawall. Using the duplex jet grout system in a single pass to 17m below platform level, the jet grouting was extended upwards into the seawall fill itself to overlap with the earlier permeation grouting. Finally a soil/cement mixed capping trench was installed using slurry trenching techniques with soil/cement/bentonite mixed backfill in order to complete the grout treatment. The approach taken allowed considerable onsite flexibility in technique. An automated slurry batching plant allowed adjustment of mixes to suit the varying subsurface conditions which were encountered during the works.IntroductionLate in 2013 Wagstaff Piling was engaged to install a seepage barrier through a rockfilled seawall built to allow expansion of sub-sea iron ore mining operations on Cockatoo Island off the remote Kimberley coast in the North West of Western Australia. Earlier stages of seawall construction had used a variety of different construction techniques with varied success, and the history of sub-sea mining on the island had been plagued with failures, including failures in the slope of the seawall itself, hanging wall failure underneath and inside the seawall, and footwall failures as the ore was mined leaving the rock face inclined at 55 degrees, parallel to the bedding. The current expansion, known as the Stage 4 expansion, was more tightly constrained by the pit geometry and available materials than previous seawall expansion stages that adopted clay core and sheet pile seepage barrier solutions. In Stage 4, an innovative grout curtain seepage barrier solution was selected to ultimately provide the necessary cut-off to allow access to high grade ore, while protecting the mine from inundation by the sea."

Jan 1, 2016

By Darren S. Diehm

"Construction for the restoration and expansion of 102-year-old Wrigley Field in Chicago, Illinois began at the conclusion of the 2014 baseball season. This six year project involves structural upgrades to the Stadium, improvements to the facade, infrastructure, restrooms, concourses, suites, press box, and bullpens, as well as the addition of restaurants, patio areas, batting tunnels, video boards, an adjacent Office-retail Tower and a new Hotel. The Bleachers were demolished and replaced, and a new underground Clubhouse was constructed for the Chicago Cubs beneath a new open-air Plaza. The 1060 Project is privately funded, projected at $750 million (US). The work will be completed in phases during consecutive off-seasons, each with a maximum 23-week duration extending through the Chicago winter. Ownership mandated that on-going construction cause no disruption to the Major League Baseball season, have no impact on hosting concerts and other special events, and it should not adversely affect seating capacity, or diminish the fan experience.The 1060 ProjectAfter purchasing the Chicago Cubs baseball team in 2009 from the Tribune Company, the Ricketts family began planning the renovation and improvement of Wrigley Field and its near neighborhood surroundings in Chicago, Illinois. What came to be known as the 1060 Project was officially announced at the annual Cubs Convention in 2013. Construction began on the $750M privately funded project in October 2014 at the conclusion of the Major League Baseball season. In their vision, the Ricketts committed the 1060 Project to three primary goals. First and foremost as a MLB franchise, the work should provide a meaningful contribution toward winning the World Series and ending the championship drought which stretched to the last win in 1908. Second, the project should be focused on preserving and improving Wrigley Field. Finally, the project should be committed to outcomes that enable the team to be a good neighbor and provide economic and social benefit to the local community.Constructed as Weeghman Park in 1914 for an estimated total cost of $250,000, the stadium provided seating for 18,000 fans and a home for the Chi-Feds and Whales of the National Federal League. The Chicago Cubs were enticed to move from the West Side Grounds in 1915. In the next 100 years, the Wrigley Field would be sliced apart and expanded, double its seating capacity with the addition of double deck grandstands, be enclosed by bleachers (and an ivy covered wall), and, in 1988, experience its first nighttime baseball game with the addition of lighting.The 1060 Project has a total budget of $750M, with an expected construction value of $350M. It is projected to add over 2,100 jobs to the economy and be completed before the 2020 baseball season. The work will be completed in phases during consecutive off-seasons, each with a maximum 23-week duration extending through the Chicago winter. Ownership mandated that on-going construction cause no disruption to the Major League Baseball season, have no impact on hosting concerts and other special events, and it should not adversely affect seating capacity, or diminish the fan experience."

Jan 1, 1900

By N. Schmitz

This paper explains how new digital solutions improve reverse circulation drilling operations. Upgrading field-proven reverse circulation drilling (RCD) rigs with new digital technologies enables semiautomated drilling, with upgrade options for fully automated & remote drilling. Key elements of the improvements are electrically controlled valve systems, process instrumentations, a state of the art machine controller and drilling operation via a touch control panel. Automation of core processes, such as adding drill pipes, reduces set-up times, increases machine uptime for drilling and as a result efficiency. While drilling, sensors provide continuous feedback, which is used to automatically adjust e.g. the weight on bit to the optimum; resulting in an increased rate of penetration and less wear and tear. While in the past hydraulic power packs (HPU) have typically been operated at a constant high-performance level with related high fuel consumption, a new interface between the machine controller and the power unit regulates the HPU performance exactly according to the actual drilling operation needs. This leads to significant fuel consumption reduction. The safety benefits of the digital improvements are the ability to remotely operate the rig in challenging site conditions via a mobile operator panel.

Sep 8, 2021

By Inc. Pile Dynamics, Daniel S. Belardo, Marcus Galvan, George Piscsalko

Soil nails are often utilized as a temporary or permanent earth retention technique for slope stabilization and for excavation retention for existing or new structures. Soils nails are generally advantageous as installation is relatively rapid and they can be installed beneath existing structures and where site access for equipment is limited. Due to the typically small cross-section of these elements, the inability to inspect the holes prior to grouting/concreting, and the various installation techniques utilized, quality control for assessing the integrity along the entire length is limited. Currently, quality assurance is conducted by load testing to verify the pull out capacity after installation. The load testing is typically done on a small percentage of the total number of soil nails. This paper will provide the results of a demonstration where the new Non-Destructive Test (NDT) method Thermal Integrity Profiling (TIP) was used to access the integrity of several soil nails along their entire lengths. This TIP method has been successfully used for several years to assess the integrity in drilled shafts and ACIP piles. The TIP method assesses the integrity across the entire cross-section and can identify regions where bulges, necks, and insufficient grout/concrete are present. TIP testing can also help assure that the contractor's installation methods are adequate and consistent for the intended design. For the project presented, instrumented Thermal Wire were affixed to the centered tension bars prior to placement in the excavated shafts. Temperature measurements were recorded from the hydration energy generated after grout/concrete placement, capturing the entire heating cycle. Manufactured defects were installed on the center bar at multiple locations. The results and conclusion will be discussed as well as recommendations for future use.

Jan 1, 2017

By Stefan Mewes

Europe’s second-largest seaport has installed a new combi wall consisting of pipe piles, sheet piles and inclined shaft grouted piles to support it. The new Liebherr piling rig with swinging leader was used to drive shaft grouted piles into a very dense soil layer of sand with glauconite. The 60 m Liebherr swinging leader was suspended at an inclination of 45° via a suspension frame and suspension ropes from the crawler crane. This inclined installation of shaft grouted piles via freely hanging swinging leader, as used for this project, is unique in Belgium. Moreover, the pile length of 43 m is a novelty for this type of pile. Shaft grouted piles consist of a steel profile with a separate box-like pile shoe with an open top. A thin grout is injected via an injection pipe during driving and emerges just above the pile shoe. As the pile is driven further down, so compressing the ground, the space above the pile foot is immediately filled with grout under pressure. This piling system is ideally suited for the transfer of high tensile loadings. It is a method to increase geotechnical load-bearing capacity and to reduce negative skin friction during pile driving.

Sep 1, 2022

By Arash Khosravifar, Nason McCullough, Stephen, Milad Souri, Scott Schlechter, E. Dickenson

The results of five centrifuge models were used to evaluate the response of pile-supported wharves subjected to inertial and liquefaction-induced lateral spreading loads. The centrifuge models contained pile groups that were embedded in rockfill dikes over layers of loose to dense sand and were shaken by a series of ground motions. The p-y curves were back-calculated for both dynamic and static loading from centrifuge data and were compared against commonly used API p-y relationships. It was found that a significant reduction in ultimate soil resistance occurred in dynamic p-y curves in partially/fully liquefied soils as compared to static p-y curves. It was also found that incorporating p-multipliers that are proportional to the pore water pressure ratio in granular materials is adequate for estimating pile demands in pseudo static analysis. 1. INTRODUCTION Liquefaction-induced ground deformations can cause severe damage to pile-supported wharves and other waterfront structures. A common approach in analyzing the lateral behavior of piles against seismic loads is using the beam on nonlinear Winkler foundation (BNWF) or p-y spring analysis. One common p-y relationship for sand is the one proposed by the American Petroleum Institute, also known as the API sand model (API 1993). While the API sand model was originally developed for the static loading conditions, it is common to modify the API sand curves for the effects of cyclic loading. However, there is no consensus on how to modify the static p-y curves for the effects of liquefaction and pore water pressure generation in loose granular soils. In previous studies, p-y springs of piles in liquefying soils were back-calculated from case histories, centrifuge model studies (e.g., Wilson et al. 2000; Brandenberg et al. 2005; Abdoun et al. 2003), full-scale tests (e.g., Rollins et al. 2005; Chang and Hutchinson 2013), and numerical analyses (e.g., McGann et al. 2011). In general, these studies found the softening effects of soil liquefaction on p-y curves, as well as a hardening behavior attributed to the dilative response of the liquefied soil around the pile. However, these studies provide varying recommendations on how to modify the static p-y curves to capture this complex behavior. Some design guidelines propose softening the static p-y curves using p-multipliers (e.g., Caltrans 2012). Other studies propose an upward concave shape for p-y curves in liquefied soils (e.g., Franke and Rollins 2013; Chang and Hutchinson 2013).

Jan 1, 2019

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 C. Dai, S Raathiv

The Waikato Expressway is one of the New Zealand Transport Agency’s (NZTA) seven roads of National Significance. Coffey is part of the City Edge Alliance engaged by NZTA for the Hamilton Section of the project. The 22km Hamilton Section is the largest and most geotechnically complex section of the Expressway. The Mangaonua gully in Sector 6 is the most challenging geotechnical area of the project for piling works. Together Coffey and Brian Perry Civil have carried out the temporary and permanent design and construction of embankments, piling works, retaining walls and soil improvement works for the bridge construction. The design and construction works were governed by weak alluvial layers and artesian pressure layers several meters beneath the ground level. This paper presents the action taken to improve the foundation of temporary platform, control the artesian pressure, prevent bentonite leakages into the highly permeable alluvial layer and challenges in the base grouting process. This paper summarises the key components in the construction and supervision of bored piling works and outlines innovative solutions for challenges which we faced during the construction.

Nov 1, 2022

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 Helen S. W. Chow, Harry G. Poulos

Most modern buildings involve the construction of a basement, often of several levels, to maximize the floor area ratio. The basement walls are generally designed for excavation retention purposes only, and are infrequently considered as elements which can help to support the structural loads from the superstructure. However, the basement walls can provide substantial stiffness and resistance to structural loads, and may contribute to the overall foundation capacity and stiffness. This paper presents a simplified approach to approximate the overall foundation capacity and stiffness considering the various components of the foundation system, including the foundation piles, the basement floor slab, the basement walls and interaction between each foundation component. The effect of the basement walls in enhancing the foundation stiffness values is examined by reference to the results of finite element analyses which consider a foundation subjected to vertical, horizontal and moment loadings. The approximate approach is found to give results that are adequate for a preliminary assessment of the effects of basement walls on the overall foundation response, without the need for detailed three-dimensional finite element analyses.

Nov 1, 2022

By Stuart Hardy, Xiangbo Qiu

The South Bank Place project comprised the redevelopment of the iconic Shell Corporation headquarters in Waterloo, located on the Southbank of the River Thames in central London. The site was originally developed in the 1950’s and due to the monitoring of the underlying Bakerloo Line tunnels by the Building Research Station it has become a seminal case history for the long term swelling behaviour of London Clay. The redevelopment, undertaken by a joint venture of Canary Wharf Group and Qatari Diar, included demolition of the existing building (with the exception of the main towers) retention of the existing basement structure and the construction of eight new mixed use buildings, up to 31 storeys in height. The foundations for the new buildings varied according to the building height and the below ground constraints. Two of the buildings are partially founded in reused under reamed piles that were installed as part of the original 1950’s development. The paper describes the novel methodology developed to assess the re-use of the under reamed piles which builds on the guidance published by CIRIA and the BRE for straight shafted piles. The paper also describes the physical investigations and numerical analyses undertaken as part of the assurance process and the procurement of latent defect insurance by the client.

May 1, 2022

By W. L. Chong, Y. Zou

There are many types of Earth Retention Systems (ERS) available in the market where more than one method can be a feasible solution for a project. This paper examines the design and construct process of a project in Dee Why, NSW using a hybrid ERS comprising contiguous piles with jet grout infill. The development comprises a deep basement and mixed-use urban superstructure. The site is located in an area of variable ground conditions, high ground water table and in proximity to existing buildings with multi-level basements. This paper details a comprehensive assessment of the geological conditions and strategies adopted to better understand the effectiveness of the proposed product and to minimise the associated risks of the proposed solution. This involved conducting additional geotechnical investigation, extensive numerical modelling and in-situ monitoring of the movements and the performance of the walls. A monitoring regime consisting of inclinometers, survey points on capping beam and prisms on the neighbouring buildings and roads surrounding shoring wall was implemented. The monitoring results were back-analysed using computer software WALLAP, Plaxis–2D and Plaxis–3D for the post-construction examinations. This paper details the effectiveness and advantages of a hybrid ERS using contiguous piles with jet grout infill.

Nov 1, 2022

By Paolo Cavalcoli, Federico Pagliacci, Marco Chiarabelli

"The Sheikh Jaber Al-Ahmad Causeway Project in Kuwait is estimated at approximately $US3.7 billion and consists of constructing a causeway across the Kuwait Bay, connecting the Shuwaikh Port with the northern Subiyah area, where the new “Silk City” will be established. The $US77 billion Silk City will revive the ancient “Silk Road” trade route and will become a major free trade zone linking central Asia with Europe. The new city will be completed in 2030, it will house about 700,000 people and, furthermore, it will include the tallest tower in the world. The Causeway will stretch approximately 23.3 miles and will be composed of a combination of low-level bridges, embankments and transition islands. A bridge of about 16.8 miles in length will span the navigation channel and a free flow interchange at the Shuwaikh Port will connect the causeway to the main road network in Kuwait City. The geo-construction portion of the project involves the execution of 1,200 drilled shafts with diameters of 98 inches and 118 inches embedded to a maximum depth of about 276 feet. Details are provided concerning the subsurface conditions, the geotechnical characteristics and the strength parameters, illustrating, as well, the installation technique implemented for the construction of the drilled shafts. In addition, particular attention is paid to the description of the challenges faced while constructing the drilled shafts at a distance of about 10 miles from the shore, such as the depth of the water above the midline (more than 160 feet), an underwater current and the tidal variation.INTRODUCTIONThis paper presents an overview of the foundation works executed for a 37km causeway across the Bay of Kuwait, connecting Shuwaikh Port with Subiyah New Town Development. The project, in which Trevi is actively engaged, includes a 27 km low-level bridge across the bay, a main bridge with a span of 200 m, an overpass and a 5 km approach road onshore in Subiyah.The main purpose of this report is to provide information about the nature and features of the applied technique of bored piles, including a description of each work phase and other related details, in order to aid in the design of the foundations for the proposed construction.Works for the soil investigation were carried out in accordance with accepted geotechnical standards/guidelines. Brief descriptions of the methodology of the field are also provided in this report."

Jan 1, 2016

By Christian L. Escalera

Over seven years ago, on October 29, 2012, Superstorm Sandy pummeled the Northeast of the United States inflicting heavy damage on New York City Transit’s (NYCT) system. Since then, NYCT has been methodically rehabilitating and hardening its assets to upgrade service and prevent future impacts caused by similar devasting storm surges. Part of these resiliency efforts, NYCT’s 207th St Yard Project is one of many projects that make up the Sandy Repair and Flood Mitigation Program. The work to be performed on the 207th Street Project includes building a perimeter Floodwall along the Harlem River, extending up 215th Street and 9th Avenue with the intent of having the ability to withstand a 500 Year Storm flooding event. The original 1,535 lineal feet of the marine side floodwall design consisted of 937 each W40x235 H-Piles continuously welded to PS 27.5 flat sheet to form an interlocked and composite steel seawall that would protect the NYCT 207th Yard from a storm surge of the Harlem River. However, after the Contract was awarded and a Notice to Proceed was issued, Walsh Construction Company II (WCCII) partnered with Mueser Rutledge Consulting Engineers (MRCE) to propose a redesign of the marine wall section as a Value Engineering Change Proposal (VECP). This VEP redesign is comprised of 279 each 54in Diameter Steel Pipe Piles that are interconnected with continuously welded PZ 35 sheet piles interlocks. The intent of the VEP was to provide a cost savings that could be shared by both parties as well as alleviate some constructability and alignment control concerns that WCCII had expressed to NYCT. The VEP allowed WCCII to substantially lower the total cost which was shared between NYCT and WCCII.

By Athena C. Denivo, Pablo V. Lopez, Sissy Nikolaou, Alfred H. Brand, Ahmad Rahimian, Rudivien G. Josef

"The United States Tennis Association (USTA) Billie Jean King National Tennis Center (BJKNTC) site is located in the northeastern portion of the Flushing Meadows Corona Park area of Queens, N.Y. The site occupies some of the most difficult subsurface conditions for construction in the New York City (NYC) metropolitan area, with unique challenges from geotechnical, seismic and foundation design perspectives.At the USTA site, Paleozoic crystalline bedrock is found at a depth of roughly 300 to 400 ft (90 to 120 m) below grade. The geologic history of the site is complicated, starting from the early Pleistocene, when the ancient Hudson River temporarily changed course, flowing across Queens enroute to the Atlantic. It eventually carved a deep valley through the Cretaceous soils, in some places all the way down to bedrock. A series of glaciers advanced and retreated across the region during the Pleistocene times, filling the deep valley with layers of assorted glacial soils. At its southern edge, the last major glacier to flow across the region built up a ridge at the southern tip of Flushing Meadows known as the Harbor Hill terminal moraine. This ridge blocked the valley forming a dam, so as ice started melting away the valley filled up with a lake fed by glacial meltwater. Layers of clean outwash sand and varved silt and clay filled the glacial lake. The ice did not retreat in a steady manner, instead periodically readvancing over the previously deposited soil in the lake, then retreating far enough to let the lake drain temporarily into Long Island Sound, before readvancing again.As a result of this repeated sequence of retreat, advance, retreat, etc., there are places where a “crust” of desiccated soil formed when the lake drained, and areas with interlayers of outwash sand where ice readvanced into the lake. When the ice melted north of Long Island Sound, the glacial lake filling Flushing Meadows drained forming Flushing Creek. During the Holocene (roughly the last 11,000 years), as ice melted further away and sea-level rose, low lying areas filled with river sands and marine clays, along with coastal marsh deposits. Table 1 lists the soil design properties on site and Figure 1 exhibits the geologic section across the site."

Jan 1, 2015

By Julie H. N. Hampden, Per G. Reinhall

"Executive summary: Impact pile driving of steel piles is a common construction practice in freshwater and marine environments for the building of structures and foundations. This practice produces extremely high sound levels underwater that have proven injurious to aquatic fish and wildlife. To limit impacts to sensitive species, resource management agencies employ a variety of different strategies including timing restrictions to limit in-water construction windows to those months when there are low flow conditions in lakes or rivers, to those hours when tides are low, or to periods of the year when species of concern are least likely to be present in the project vicinity. In addition, permitting agencies have identified noise thresholds above which sensitive species could be injured, resulting in additional project conditions to curtail the extent of project noise impacts including: limiting the number of piles or pile strikes per day, requiring biological monitoring, and mandating the use of noise attenuation techniques, such as bubble curtains and cofferdams. Numerous studies have shown current noise attenuation techniques are costly and provide limited or variable noise reduction [1-3]. This is because the noise from pile driving is not only transmitted through the water column, it is also transmitted through the sediment back into the water column [1, 4-8]. Though these protective measures may help to reduce project impacts, they also result in additional complexity, expense, and potential risk for project delivery. Marine Construction Technologies, a Public Benefit Corporation, in collaboration with University of Washington and Washington State Department of Transportation, has developed a pile that can be installed with standard pile driving technologies (vibratory or impact hammers) and consistently decreases the total noise transmitted into the water. The double-walled pile is relatively quiet in comparison to unattenuated piles or existing noise attenuation techniques. This technology not only reduces the risk to sensitive species by minimizing the extent of potential impacts, it also reduces potential risks to project delivery by limiting the size of monitoring areas, minimizing the need to cap daily production rates, and eliminating the need for deployment of additional noise attenuation devices. Results from finite element modeling of the pile, scaled prototype testing, and full scale field testing in Commencement Bay (October 2014) and Vashon Island (October 2015) in Puget Sound, Washington indicate a reduction the peak sound pressure between 14 and 20 dB relative to single walled piles at a range of approximately 10 meters. These tests also confirm that the double-walled piles provide drivability similar to standard steel piles. In addition, preliminary calculations for capacity and structural characteristics demonstrate that double-walled piles provide equivalent or better performance than same-sized standard piles."

Jan 1, 2017

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

By Scott A. Walker, Gabriel J. Alcantar, Brian Zuckerman, Ramin Golesorkhi

"The stadium development consists of construction of a 68,500-seat, open-air NFL football stadium for the San Francisco 49ers. The main structure will consist of a 7-story above grade steel structure supported by over 3,000 piles. Berkel and Company Contractors, Inc. (Berkel) was selected as the design-build pile contractor who used their auger pressure grouted displacement (APGD) piles for this project. During an indicator pile installation and pile load test program, fifteen piles were tested to develop installation criteria to support demands of 150kips tension and 180 kips compression. Following the indicator pile program Berkel installed 3088 piles in 30 working days. Throughout pile installation data were collected with an automated data acquisition system (DAS). During pile installation field engineers from Treadwell & Rollo observed the pile installation as well as the real-time data from the DAS. Strategic staging and pre-production planning by Berkel along with consistent collaboration with the design team created an atmosphere for a successful and on schedule project completion.IntroductionThe new San Francisco 49ers Stadium in Santa Clara, California will be a 68,500-seat facility, a rendering of which is shown in Figure 1. The main structure will consist of a 7-story above grade steel structure supported by more than 3,000 piles. The north, east and south portions of the stadium are designed as an open seating bowl, while the western portion includes open seating at the lower levels and seven-story tower which houses over 150 suites.The stadium project includes the stadium structure, as well as elevated open pedestrian walkways, commercial community space, and three new pedestrian bridges spanning a nearby by creek. Sustainable designs and innovations such as a green roof, photovoltaic panels, a ground source geothermal system, stadium-wide Wi-Fi capability, and access to public transit are provided throughout the project. The stadium is designed as an open, light, and airy structure and is surrounded by an existing amusement park, office buildings, the Santa Clara Convention Center, and the training facility of the 49ers."

Jan 1, 2015