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By Tracy Brettmann

The Highway 146 Bridge Expansion Project across the Clear Creek Channel in Houston, Texas was designed on driven precast concrete piles. However, during construction, the piles along one side of the bridge along the main channel encountered obstructions and couldn’t be installed. These obstructions turned out to be the remnants of a previous bridge foundation at this location, which was unknown to the designers since that bridge had been demolished 40 years ago. Those old foundations were massive 20 ft by 40 ft (6 m by 12 m) pile caps 11 ft (3.3 m) thick supported on precast concrete piles 37 to 55 ft (11 to 17 m) long. The foundation re-design for these locations involved installing a single 78 inch (2 m) diameter drilled shaft up to 125 ft (38 m) long to replace the originally planned driven pile supported pile cap. The drilled shafts would need to be installed within very tight tolerances since they were supporting a single bridge column directly above it. In addition to drilling through the obstructions, this work would need to be completed from barges in 30 ft (9 m) of water capable of dealing with both the current and tides affecting this area. The shafts were installed using a multi-step process. The first step involved coring a larger diameter 100 inch (2.5 m) hole through the reinforced concrete pile cap and removing the concrete inside. This was followed by the installation of a 72 ft (22 m) long permanent casing to and removing the soil and existing precast piles inside. Finally, the drilled shaft excavations were advanced to the completion depths (uncased) using bentonite slurry as the support fluid.

May 1, 2022

By Yu Chuang, Zai Jinmin, Liu Songyu

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

Jan 1, 2005

By A. Bozorgzadeh, B. M. Jensen, B. N. Koelling, B. R. Murtaugh

"The Service Base mooring system originally consisted of two general types of structures, 19 timber piles cabled together and steel three-legged pipe piles. The St. Louis District fleet moored to the fleet barges which were tied off to shore-side concrete deadman and supported on the landward side by the timber and steel piles. The purpose of this project was to replace the existing floating wharf mooring system at the St. Louis Service Base. The Marine Design Center of the U.S. Corps of Engineers developed a three pile cluster system concept. The clusters consisted of one vertical pile and two batter piles. Piles in rock sockets were selected to resist the uplift loads due to high wind loads on the tall, spare lock gates stored at the floating wharf. This paper focuses on the design of the rock sockets for steel pipe piles with large uplift loads and the lessons learned during the design and construction of this system.INTRODUCTIONBackgroundThe U.S. Army Corps of Engineers’ St. Louis District is located at the critical transition point on the Mississippi River where it is a “locking river” north of St. Louis and an “open river” to the south. The St. Louis District is responsible for maintaining navigation channels on the Mississippi River, the Illinois River and the Kaskaskia River. It is also responsible for the operation and maintenance of five locks and dams within its geographic boundaries.The St. Louis District utilizes a fleet of vessels (dredges, crane barges, motor vessels, and barges) to support the navigation mission identified above. The St. Louis District Service Base, located in St. Louis, Missouri, serves as the base of operations for the district fleet. This riverfront facility originally consisted of a floating wharf, a railroad trestle, and a walkway down the river bank to the floating wharf. Historically, there have been two fleeting areas at the Service Base. The main fleeting area was approximately 965 feet long and consisted of six fleet barges (Figure 1). This area supported the Dredge Potter and its attendant fleet. The upper fleeting area was approximately 1,050 feet long and consisted of various stop log, crane and work barges, dredge pipe pontoons and work flats."

Jan 1, 2017

By Joseph A. Mann

"Soil mixing is a proven solution for the construction of ground improvement adjacent to sensitive structures due to the use of computer controlled and monitored equipment. The precision to which geometry is controlled can often be the deciding factor for selection of soil mixing versus other means of ground improvement. Protection of existing structures and utilities requires careful planning, investigation, and may demand supplemental control measures. During planning, it is imperative that the process be fully developed by the project team to ensure proper control measures are budgeted; otherwise, the success and safety of a project can be jeopardized.This paper discusses case histories of soil mixing performed in close proximity to large, sensitive, and critical utilities, including foundation support for an existing earthen dam impounding a water reservoir in upstate NY, a buffer zone for a tunnel drop shaft at an operating wastewater treatment plant in Washington DC, and a containment system to protect a major water line along an interstate widening project in Baltimore, MD. The function of soil mixing as ground improvement varied; however, the selection and application of the technique versus other means of ground improvement was specific due to the controlled manner of construction with soil mixing. Through the three case studies, small diameter (3- ft [0.9 m]), large diameter (8-ft [2.4 m]), and mass mixing applications will be discussed. Furthermore, the case studies offer insight into how the geotechnical community in the Mid-Atlantic utilizes soil mixing technology for widely varying applications. Additional topics of discussion will be the design and construction of the ground improvement systems, procedures and execution of the work to protect existing structures, and the QA/QC methods, procedures, and results from the projects.INTRODUCTIONWet soil mixing, also known as the Deep Mixing Method, is a ground improvement technique that improves the characteristics of weak soils by mechanically mixing them with cementitious binder slurry. To construct columns, a powerful drill advances a mixing tool with radial mixing paddles located near the bottom of the drill string. The binder slurry is pumped through the drill string to the tool as it advances and additional soil mixing is achieved as the tool is withdrawn.Wet soil mixing is applicable in a wide range of soils. Soil mixing has been performed at depths more than 100 lf (30 m). Soils vary widely in their ability to be mixed, depending on the soil type, strength, water content, plasticity, stratigraphy, and texture. Almost any soil type, including organics, can be treated with certain soil mixing technologies, although they may require high binder contents and/or pretreatment to achieve the required results. In cases when the target soil is very soft, including some very weak clays and peats, 100% of the soil may require treatment. This complete coverage of soil mixing is referred to as mass mixing."

Jan 1, 2015

By Henry Zhang

This paper presents two case studies of large diameter driven tubular steel piles for the ongoing Woolgoolga to Ballina Pacific Highway upgrade (W2B). This project forms part of Australia’s largest regional infrastructure project and will upgrade about 155 kilometers of highway to four-lane, divided road. There are more than 170 bridges on W2B, and driven tubular steel piles are adopted on 43 bridges between Glenugie and Ballina. Driven piles terminating in soil or basalt is a big challenge faced by both designers and piling contractors due to 1) the uncertainty of expected pile unit shaft and base resistance in different soils; 2) whether plugging is formed; and 3) highly variable basalt strength and thickness near top of the rock. If these risks are not adequately managed during design or construction stages, it could lead to unexpected project delay, extra time and cost or pile toe damage in basalt. This paper describes two case studies, one for piles designed to terminate in soils and the other for piles designed to terminate in basalt. How these risks were assessed and managed during detailed design, procurement, hammer selection, pile installation and verification will be discussed in details with lessons learnt summerised in the conclusion.

Nov 1, 2022

By Aaron Evans, Chu E. Ho, Tom Richards

"This paper describes an innovative case history of using jet grouting to form a groundwater cutoff wall at the interface of a cut-and-cover construction and an existing tunnel. The design of the jet grouting layout was complicated by the presence of a left-in-place bulkhead of unknown dimensions abandoned by previous construction of the existing tunnel. Jet grouting was performed through predrilled holes within the narrow space between the existing bulkhead sheeting and tunnel structure. A systematic sequence of primary and secondary jet grout elements of varying diameters and panel lengths was executed to achieve an effective groundwater barrier. A key challenge in the jet grout design was the impact of potential deviations due to shadowing effects of the left-in-place bulkhead sheeting and pre-formed jet grout columns, as well as overbreak concrete in adjacent secant pile walls. The flexibility of the jet grouting methodology enabled a wide range of operational parameter combinations to be performed, allowing column diameters to be adjusted based on actual field installation measurements. Special precaution was exercised when grouting at critical locations to avoid over-pressurization and damage to the existing tunnel structure.IntroductionThe 96th Street Station box for the new Second Avenue Subway Line in Manhattan, New York included a transition tunnel, which connected the station to an existing tunnel built in the early 1970s (Figure 1). The new station and transition tunnel were both constructed using the cut-and-cover technique with bottom-up sequence (Aksman et al. 2012, Grigson et al. 2016). The main station structure incorporated permanent diaphragm walls for most of its length, except for the southern segment where high rock levels were encountered and the station box was constructed within temporary secant pile walls socketed into the rock. The permanent diaphragm walls were also utilized for temporary excavation support (Ho and Hu 2014). At the northern end of the site, the new transition tunnel was constructed within temporary secant pile walls that extended from the station diaphragm walls to the existing tunnel at the tie-in location. A temporary traffic deck spanning 60ft across the secant pile and diaphragm walls along the full excavated length of the site allowed traffic to continue operating at street level while construction of the station and transition tunnel progressed below grade."

Jan 1, 2016

By Camilo A. Alvarez, Stephen K. Harris, Brian R. Zuckerman, Philip J. Meymand, Danielle M. Steinmetz

"The sleek new air traffic control tower at the San Francisco International Airport stands at 221 feet tall and is set to replace the existing air traffic control tower by 2016. This aluminum-clad, torch-like structure and three-story Integrated Facilities Building at the base are situated between Terminal 1 and Terminal 2 adjacent to the tarmac. Berkel & Company Contractors, Inc. and Simpson Gumpertz & Heger Inc. worked in conjunction with structural engineers from Walter P. Moore Engineers and Consultants, geotechnical engineers from URS Corporation, architects from Fentress Architects, and general contractors from Hensel Phelps Construction Company on the performance-based design of a foundation to support this critical facility, which is located in a high seismic zone and situated on the very soft soil of the San Francisco Bay margin. With the loading demands and performance criteria established and Young Bay Mud thicknesses ranging from 44 to 47 feet thick across the site, the design team employed a total of 214 24-inch diameter Auger Pressure Grouted piles, which were drilled into the underlying Franciscan Formation as deep as 148 feet below existing grade. Pile reinforcement included full-length confined cages.The piles were designed to resist Maximum Considered Earthquake axial demands as high as 1,400 kips in compression and 700 kips in tension. The performance-based pile design included verification of shear capacity under double-plastic-hinge flexural mechanisms, verification of pile ductility via non-linear moment-curvature analyses, and consideration of curvatures due to kinematic as well as inertial loading.The team implemented an extensive pile load test program including a full-scale static compressive load test on a sacrificial test pile and five non-destructive high-strain dynamic load tests, four of which were performed on indicator piles that were later used as part of the foundation system. These piles were monitored with extensive embedded instrumentation throughout their length, including strain gauges and accelerometers."

Jan 1, 2017

By William M. Tanner, Daniel C. Brahana

"A drilled pier foundation was originally designed to support the proposed G. Wayne Clough Undergraduate Learning Commons on the campus of Georgia Tech in Atlanta, GA. Reflective of the site geology, the original drilled pier foundation was divided into a Northern and Southern portion with an allowable end bearing capacity of 60 ksf and 100 ksf, respectively. After initial pricing on the original design, several value engineering options were submitted that featured changes to the original design capacity and construction method. The project team selected the value engineering option that involved conducting an Osterberg Load Cell test to assess end bearing of the site bedrock and skin friction. Results of the Osterberg Load Cell test justified increasing the allowable end bearing capacity of the site bedrock to 100 ksf in the Northern portion and 125 ksf in the Southern portion. Considering the final foundation design and Osterberg Load Cell test program, a net savings of approximately $259,000, or approximately 34%, was obtained over the original design.Project BackgroundThe G. Wayne Clough Undergraduate Learning Commons (CULC) is a 5-story academic building on the Georgia Tech campus in Atlanta, Georgia. The CULC was completed in 2011 and consists of a concrete frame structure supported on a drilled pier foundation.After pricing of the original drilled pier foundation design, several value engineering (VE) analyses were performed by the foundation contractor in an effort to demonstrate the potential for a reduced foundation cost. The VE analyses focused on variations in design assumptions, as well as construction techniques. This paper presents a case study that demonstrates how the value engineering process can be used to reduce foundation costs.Site Investigation and Subsurface ConditionsThe CULC building site is located within the Southern Piedmont Physiographic Province, an area underlain by metamorphic and igneous rocks. McConnell and Abrams (1984) indicate that the site is located at the boundary between two distinct geologic formations. The Northern portion of the site is underlain by the Wahoo Creek Formation while the Southern portion of the site is underlain by the Stonewall Formation. The following paragraphs briefly describe the geotechnical investigations performed by the project geotechnical engineer (GE) for the CULC."

Jan 1, 2015

By Andrew McNamara, Stuart Norman, Matthew Dearing, Michael Pelken, Asha Panchal

The deep foundations industry has largely remained unchanged since in the advent of CFA piling in the 1960s. Piles have consequently been designed and constructed following the traditional codes and standards without much regard for optimising in-life efficiency or end-of-life reuse. After existing developments have been demolished there is little motivation to reuse existing piled foundations as their load bearing capacity and structural integrity cannot be verified. Therefore piling contractors are increasingly spending more resources on coring through existing piles, only to be replaced with larger diameter or deeper piles. The hollow element of the HIPER® Pile provides access to the entire length of the pile to permit inspections and a shaft in which the pile can be extended if needed. This paper presents and compares the embodied carbon savings, both during construction and through foundation reuse, from a HIPER® Pile scheme compared with the traditional solid pile scheme. A discussion on the benefits of this technology and its implications on warranties and approvals is also presented to motivate the foundations industry to embrace whole lifecycle assessments and support the journey to net-zero carbon.

May 1, 2022

By Justin Simmons, Michael Arnold, Bob Faulhaber

"In order to remodel an existing beach resort on the Gulf of Mexico, an existing three story structure, founded on stepped tapered piles, was to be replaced by a ten-story building with service rooms on a daylight basement level, conference rooms on the next levels and up-scale hotel rooms on the upper levels. The new building was founded on augered-cast-in-place (ACIP) piles. The pile caps and the basement required excavations between nine and fifteen feet (three to five meters) below ground surface.BAUER Foundations Corp. (BFC) successfully used Cutter Soil Mixing (CSM) to install the support of excavation walls. This technique allowed for the adjustment of the wall alignment during execution in order to avoid existing and new piles and other underground obstructions. Nearly 1600 – 16-inch (400 mm diameter) ACIP piles were installed to an average depth of 71.5 feet (22m) below ground surface (BGS) by BFC to support the new hotel structure. Initial grout overages in piles were excessively high and ground stability issues were encountered in some pile locations. By identifying specific areas of concern BFC was able to modify the approach to ACIP installation, effectively mitigating the ongoing risks and successfully completed the project.PROJECTMarriott Hotels began the $300 million renovation and upgrade of their Marco Island Marriott Beach Club Hotel in Marco Island, FL to JW Marriott status in May 2015. The renovation included the demolition of a portion of their existing hotel tower, and the construction of a new 10-story hotel tower consisting of 94 new guest rooms and a 10,000 SF (900 m2) ballroom, among other amenities. As is typical with hotel construction, time was of the essence. The schedule was the driving factor of this project as the owner had already booked events in their new ballroom starting in January of 2017.BFC provided the client with a deep foundation package that included the installation of 1562 Augered Cast-In-Place (ACIP) piles supporting the new tower, and the design and construction of approximately 36,500 SF (3,400 m2) of soil-mixed retaining wall for support of excavation (SoE)."

Jan 1, 2017

By Giulia M. B., Ferruccio Cribari, Alessandro Bertero, Eliano Romani, Roberto Sorge, Francesca Casini

"The use of Artificial Ground Freezing (AGF) to form earth support and seepage control barrier systems has had applications worldwide. These cover a variety of construction problems, including the formation of frozen earth walls to support deep excavations, structural underpinning for foundation improvement, and temporary control of ground water in construction processes. An application of AGF during construction of Line C of Rome underground is described in detail.The new line “C” of San Giovanni metro station was constructed adjacent to the existing line “A” of San Giovanni station; the new metro line “C” is deeper than line “A” and runs below the existing station. The underpass project envisages an Artificial Ground Freezing in order to create a structural and waterproof temporary cut-off suitable to the two new tunnels excavation, while keeping trains running in the safest possible condition. The excavation of tunnels under the water table, with a hydraulic head of over 10 m in not homogeneous soils having different mechanical properties and permeability and below existing sensitive structures, involves special ground freezing sequences and methods, as well as peculiar drilling systems and operations, such as TDDT (Trevi Directional Drilling Technology).Artifical Ground Freezing IntroductionNatural freezing occurs seasonally in many areas of the globe and can affect negatively the engineering performance of geotechnical structures; on the other hand, man-made freezing is a controllable process that can be used by civil engineers to stabilise temporarily the ground in order to support and/or exclude groundwater from an excavation until the final retaining and lining structures are constructed. Freezing and thawing of the pore fluid within soils involve complex thermal, hydraulic and mechanical processes that have significant mutual interactions. For example, phase changes of the pore fluid caused by temperature variations can modify the pore water pressure in the soil, which, in turn, can induce mechanical deformation. At the same time, any changes in the hydraulic and mechanical conditions affect the thermal processes by advection and changes of ice and water contents.An application of AGF which will be presented in the paper, refers to the construction works of Line C of Rome underground. In this case AGF was carried out to provide temporary support during excavation of the two Line C running tunnels directly underneath the existing S. Giovanni station of Line A, in the safest possible condition. In order to keep the trains of Line A operational during excavation, a temporary structure was installed and a real-time monitoring system was conceived in order to control the temperatures of the soil during freezing and the response of the structures of the existing station."

Jan 1, 2016

By Sanjeev Malhotra

"This paper presents the results of a pile installation monitoring and performance assessment program for pile foundations supporting 14 piers and 2 abutments of the 1700-ft long bridge crossing over a river in Baltimore, Maryland. Dynamic measurements were conducted during installation and restrike of 16 test piles, one at each support location. The foundation piles were 30-inch diameter, 0.75 inch thick pipe piles at the piers and 24-inch diameter, 0.5 inch thick at the abutments. The piles at the piers were approximately 100 ft long and were designed to carry 260 kips service load with a factor of safety of 2.25. The piles were driven open ended into a variable site stratigraphy containing recent deposits of organic clayey silts near the mudline followed by loose to medium dense sand, with some silt, and then by soil deposits from the Cretaceous period consisting primarily of dense to very dense, poorly to well graded sands and gravels and cobbles, with occasional seams of very hard to very stiff, low to moderate plasticity silts and clays. This paper presents the approach taken to evaluate the driven index piles and to develop criteria for driving production piles. It provides the Engineer with some data on pile driveability in Cretaceous soils in the Baltimore area, soil set-up effect, and an estimate of pile capacity.INTRODUCTIONThe typical approach to pile foundation design and construction should include an indicator pile program with dynamic measurements and a static load test program. However very often paucity of funds and schedule constraints cause an owner to do away with conventional static load testing which can take $25,000 to $100,000 and several weeks per test. This paper examines an alternate (though not equivalent) truncated approach to foundation assessment and presents a case history where this approach was implemented.Dynamic measurements were conducted during pile installation for the 14 piers and 2 abutments of the new 1700-ft long bridge over a river in Baltimore, Maryland. Strain transducers and accelerometers were attached to the pile top during initial driving and restrike of 16 pipe piles. The foundation piles consisted of 30-inch outside diameter, 0.75-inch thick pipe piles at the piers and 24-inch outside diameter, 0.5 inch thick at the abutments. The piles were driven open ended into a variable site stratigraphy. The approach taken to assess the foundation performance included 1) a pre-field wave equation driveability analyses, 2) field pile driving measurements, 3) post-field Case Pile Wave Equation Analyses (CAPWAP), and, 4) revised wave equation analyses based on field and CAPWAP data. The following sections describe in greater detail each of the steps taken to assess foundation performance and the results obtained."

Jan 1, 2005

By Henry H. Tayler, Eric Sturel

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

May 1, 2022

By Chu E. Ho, Alfredas Daugiala, Nicola Ebanks

"The construction of an ancillary structure for the new Second Avenue Subway Line in Manhattan, New York City involved a deep excavation in highly variable rock conditions adjacent to a fragile masonry building. The maximum difference between the lowest and highest rock elevations was about 30 feet, which posed a problem for the installation of secant piles that formed the supporting retaining wall for the excavation. At certain areas, the rock levels were higher than the top of the invert slab of the ancillary structure. To avoid disturbance to the adjacent fragile building, the secant piles were fully cased for drilling through the overburden soils and the rock sockets were formed using non-vibratory technique. This paper discusses the design and installation details of the secant pile wall and the contingency measures that were considered to mitigate the highly variable rock conditions. Monitoring of the adjacent fragile building showed that impact of pile installation were controlled within tolerable limits and safety of the building was not compromised.INTRODUCTIONThe 96th Street Station forms part of the newly constructed Second Avenue Subway Line on the East side of Manhattan Island, New York City (Figure 1). During construction of this station, several deep excavations were carried out adjacent to existing fragile buildings (Arksman et al. 2012, Grigson et al. 2016). These fragile buildings were typically four to five stories high, with a single rubble wall basement supported on timber piles or seated directly on the fill. The timber piles were often found to be in a poor condition and connections to the footings were compromised due to rotting of the timber within the zone of water table fluctuation. Several of these fragile buildings had to be strengthened and underpinned to improve the stability of the structures prior to commencement of excavation for the new subway station box (Trabold et al. 2012, Ho and Pena-Iguaran, 2013). The situation was most challenging at Ancillary Buildings 1 and 2 located at 93rd and 97th Street respectively, where secant pile walls were located merely 2 feet away from the adjacent property line, due to architectural space constraints. While mitigation of excavation induced ground movements can be controlled by the adoption of a stiff excavation support system, a more concerning factor was the uncertainty associated with the impact of the secant pile wall installation on the stability of the existing fragile buildings. This was particularly difficult at Ancillary 1 where the secant piles encountered highly variable rock levels that intruded into the excavation space. The following sections discuss the design and installation of the secant pile wall and contingency measures that were considered at Ancillary 1."

Jan 1, 2016

By Selvaganesh Selvaraju, Deepak Raj, Sandun N. Wimalasena

One of the world leading oil majors is carrying out a multi-billion-dollar expansion of its integrated manufacturing complex in Jurong Island, Singapore, the global oil trading and refining hub. Soil conditions at the site comprise 10-20m thick reclaimed sand, below which is 3-5m of soft marine clay underlain by stiff soils of the Jurong Formation. The conventional foundation solution would adopt driven precast concrete spun piles; however, precast spun piles have a high embodied carbon from the usage of steel and cement. In order to reduce the carbon footprint, an alternative solution comprising deep vibro techniques was developed. The EFFC-DFI carbon calculator was used to demonstrate the expected scope 1, 2 and 3 carbon emissions for both driven pile and vibro techniques. By using in-house, state-of-the-art fuel-efficient machines, alongside the innovative design concept and usage of natural materials such as sand and stones, actual CO2e emissions were reduced from a potential 21,000 tonnes, with the spun pile’s solution, to only 1,900 tonnes. The saved 20,100 tCO2e is equivalent to an average car driving 2,000x around the Earth’s equator. The paper discusses the application of soil improvement as a more sustainable, lower carbon alternative to conventional piled solutions.

May 1, 2022

By Raymond J. Poletto

This paper describes the special problems that occur with the construction of diaphragm walls and discusses the lessons learned during the repairs of structural walls. Although diaphragm or slurry wall technology and equipment has vastly improved since its development in the late 1950?s, significant problems still occur. Key issues are repairs related to panel joints between wall panels, concrete defects associated with tremie concrete problems, leaks and other defects at tieback reservations or inserts, wall leaks within the plane of the wall and surface repairs. The paper supports the position that diaphragm walls are relatively watertight when properly constructed, but cautions that it is necessary to address potential problems in the design stage and allow for flexibility in construction so that the problems that occur can be corrected once encountered. Due to the fast track nature of most projects the time available for design, detailing and construction is limited. As a result, insufficient attention to detail by any of the responsible parties can lead to imperfections and defects in the wall. The authors describe the nature of these problems and their potential resolution based on ?lessons learned.? The timely response to wall problems is essential to the successful completion of a diaphragm wall project. Appropriate repairs have resulted in largely successful jobs starting with the World Trade Center in New York City. The authors? total 80 years of experience as the engineer of record and designer, inspector and contractor?s representative for the diaphragm wall results in a unique insight to deal with these problems.

Jan 1, 2011

By Thomas Domanski

Any type of deep excavation whether for Bored Piling, Diaphragm Walls or Contiguous Bored Piling Walls depends on forming a stable borehole with a defined cross-section to receive safely the permanent materials. In modern construction the excavation depth can reach well the range of 100 m and above. The diameters of the Piles reach often sizes of 2.5 m and bigger. Top casings in Bored Piles (Diaphragm Wall none) are rather short and stability below the casing, need to be secured by stabilization slurry. The boreholes need to be formed through a variety of different materials and stand open for an extended period. Without a safe stable borehole, it is impossible to produce quality products and work cost-efficient. The understanding and proper usage of a suitable slurry is a key element essential for the delivery of Foundation Elements with high quality and within a reasonable budget. The setting of mechanical and rheological parameters in specifications is necessary and helpful, but probably insufficient to embrace and control such a key element in the practical implementation of foundation construction. The proper selection, design, implementation and supervision of slurries on site requires both from Contractors and Engineers to understand how different slurries do function. Only with this knowledge the right decisions in slurry operations can be made. This talk is directed to give some help to both, Contractor’s and Engineer’s, in understanding how different type of slurries do work. (Which ones should be preferred in what kind of soils.) The better knowledge will help the Contractor to control cost and enhance production. The Engineer will be able to assist in arriving at the appropriate technical choices and include in the specifications.

Sep 1, 2022

By Richard Shea

Morris-Shea, an Alabama-based deep foundation contractor, is installing foundation piles at the sites of North America's two largest liquefied natural gas (LNG) terminals currently under construction. The contractor has crews working at Venture Global's LNG lique- faction plant in Plaquemines Parish, Louisiana, as well as constructing foundations for the Cheniere Energy Stage 3 Liquefaction Project in Corpus Christi, Texas. This work includes installing ap- proximately 27,000 DeWaal drilled, full displacement, cast-in-place concrete piles to support seven new midscale LNG trains at Cheniere's Texas ter- minal. Deep foundation installation began at Venture Global's Plaquemines facility, located approximately 30 mi (50 km) south of New Orleans, with an initial phase of 24,000 piles. Plans for the Plaquemines LNG terminal include three loading berths on the Mississippi River and four LNG containment tanks. The facility will utilize new pretreatment com- pressors, liquefaction trains and on- site gas turbine power plants to maintain an annual LNG export capacity of nearly 20 million tons (18 million tonnes) per annum. The site's LNG trains are configured in 18 blocks. The contractor is installing piles through an initial 6-20 ft (1.8-6 m) of cement mixed improved soils, which provide a safe work plat- form for equipment to operate on the extremely weak native soils. Drilling continues through soft clay in the subsurface and tips into a stiff clay or dense sand layer. Production piles are drilled to depths up to 124 ft (38 m) below ground surface. The firm is working with engi- neering, procurement and construction contractor KZJV, a Kellogg Brown & Root and Zachry joint venture, at the Louisi- ana location. The foundation team mobilized at the Plaquemines site in May 2022, to install 16, 18 and 24 in (400, 450 and 600 mm) diameter test piles to depths of 90 and 120 ft (27 and 36 m). The piling contractor returned in September 2022, to start Phase 1 of the deep foundation project, beginning installation of production piles.

Apr 1, 2023

By Hiren J. Shah

Across much of New York City, the geology of glacially deposited soils follows a common sequence. Outwash sands generally overlie varved silts and clays, which lie above a basal till deposit underlain by the bedrock. Pile foundations at projects with such typical stratigraphy generally develop their axial capacities by extending below the fine-grained deposits into the till or the bedrock. Contrastingly, at a project site on the Brooklyn waterfront, high capacity piles were efficiently and economically installed by driving them into the relatively shallow glacial drift and till deposits which lay above thick fine-grained compressible glacial lake deposits. An unusual aspect about the foundation design at the Brooklyn project site is that, relatively short and high capacity piles were driven into the shallow glacial drift and till deposits, overlying the thick fine-grained glacial lake deposits. In order for this unusual foundation scheme to be feasible and economical, the piles needed to achieve their driving criteria in the upper strata. Consolidation settlements in the lower stiff and over-consolidated glacial lake deposits below the pile tips had to be relatively small. The paper discusses the unusual stratigraphy in this area of Brooklyn in greater detail with geologic profiles and engineering characteristics of the glacial strata. It also discusses the design aspects of the pile foundations, settlement estimates, a pile drive test program during design, results of the static load test program during construction, and production pile installation results.

Jan 1, 2008

By Takefumi Takuma, Tsunenobu Nozaki, Masashi Nagano

Using sheet piles and pipe piles for permanent earth retaining is one of the most economical methods for constructing basement walls since they can also work as temporary shoring during construction. A major mixed-use redevelopment project in the UK, encompassing two to three large city blocks, utilized both sheet and pipe pile walls for a two-level subterranean parking structure. The 290m (950ft) x 100m (330ft) basement’s steel walls were designed to temporarily support excavation during construction and eventually to become a load carrying permanent structure in order to expedite the construction process and to achieve cost reduction. Two types of press-in piling machines, one for sheet piles and the other for pipe piles, were used for the job because of their abilities to press in sheet and pipe piles within tight tolerances for finished walls, for difficult installation conditions with very hard soil, and for its very low noise and practically zero-vibration operation; an essential factor for the job in close proximity to other businesses and residents. BACKGROUND Steel sheet pile and pipe piles have been used for many purposes including earth retaining. They are produced at steel mills and spirally welded at a fabrication yard to their corresponding specifications under strict quality control measures. Therefore, they can form highly reliable walls to its design capacity with proper installations. Their advantages as underground walls are:  They can form a high level of water cut-off function with their interlocks sealed by welding or with hydrophilic materials. See Figure 1 for a few examples for a sheet pile application.  They can carry vertical loading in addition to horizontal load and bending moment.  They can be a self-standing and temporary/permanent wall with flexible design and construction processes; bottom-up, top-down or hybrid sequences can be chosen per the project’s needs.  They can form a thinner wall than other wall types, creating larger inner space. See Figure 2.

Jan 1, 2019