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By Jr NeSmith

"Drilled Displacement piles are a product of screw pile technology originally developed in Europe. The process involves rotating tool into the ground that displaces the soil laterally as it advances, then grouting or concreting through the hollow stem of the tool as it is withdrawn. They were first introduced in the United States in the 1990’s and have become a mature and accepted technology since that time. They are now used to support a variety of heavily loaded structures including electric power and LNG facilities, stadiums and arenas, airports and mid- to high-rise commercial and residential facilities. In urban environments, the technique has a number of advantages including, low noise and vibrations, no removal of the existing soil, and reduced pile material cost due to the improved stress state of granular soils after installation (smaller or shorter piles can be used). For these reasons, displacement piles have been used to support various facilities in Northeastern United States (US). The paper presents case histories of the performance of displacement piles in the Northeastern US including the use of full displacement elements as a settlement limiting ground improvement system.INTRODUCTION“Drilled Displacement” (DD) is an industry umbrella term for a number of proprietary or commercially available cast-in-place pile installation systems which involve a hollow-stem tool that laterally displaces soil as it advances and the placement of grout or concrete through the hollow-stem tool as it is withdrawn. The systems include grout/concrete placement methods by both sand-cement grout pumped under pressure and tremie grout/concrete placement through bottom-hole discharge. The system discussed in this paper includes grout pumped under pressure, also referred to as Auger Pressure Grouted Displacement (APGD). A schematic of the APGD tool is shown in Figure 1. The tools require significant torque and downward force to advance; a typical installation platform is shown in Figure 2."

Jan 1, 2016

By Jeff Wilkinson, Brandon Walter

"A&N Electrical Cooperative provides electrical service to the counties of Accomack and Northampton along Virginia’s Eastern Shore and to Smith Island in Somerset County, Md.A&N recently worked to improve the efficiency of power distribution to a small island community and marina on Tangier Island in the Chesapeake Bay. This improvement consisted of upgrading the existing distribution substation with a new 25 kV 2-bay box distribution structure. Earth Contact Products (ECP) collaborated with PowerServices, Inc. (PSI) to design and install a helical foundation support system as part of the substation upgrade. Feasibility EvaluationThroughout the design process, A&Nworked with its partners PSI (design) andT&D Solutions (installation) to identifycost-effective alternatives. Foundationsystems considered included cast-in-placereinforced concrete caissons, precastconcrete foundations, driven steel piles and helical piles. In evaluating all of theoptions, the greatest concern was gettingthe material onto the island, followedclosely by the availability of the equipmentto install the foundations. Clearly, cost,more specifically the installed cost, was asignificant consideration and decisionfactor throughout the process.There were several limiting factors that had to be considered during the design process, the most significant of which was that all of the material had to be barged to the site. With traditional reinforced concrete deep foundations in mind, the cost for installing these piles was projected to be nearly $2,000/cu yd ($262/cu m) of installed concrete. Given that approximately 5 to 6 cu yd (3.8 to 4.6 cu m) of concrete would be required for this structure, the cost was significantly high for this project. What’s more, because the components of the concrete mix would have to be barged and then hand mixed on site, there was concern regarding both the time required to complete the piles and the quality of the installed concrete. For the driven pile alternative, the availability, or lack thereof, of equipment and material cost resulted in a total cost estimate that was more expensive than that of the concrete piling alternative. The high material cost for the piles, which was more than double than the cost of concrete, was due to the number and size of piles needed to resist the overturning moment. Ultimately, the team selected the helical pile alternative. The decision to a use helical pile foundation system was based on many factors, not the least of which was the remote location of the project site and the difficulties associated with getting material, equipment and construction personnel to the project site."

Jan 1, 2017

By Kazunori Matsushita, Masaru Sakakibara, Kenji Harada, Naotoshi Shinkawa, Mitsuo Nozu

The Sand Compaction Pile (SCP) method has been widely used as a typical countermeasure against liquefaction in Japan, and its effectiveness has been confirmed in many case histories of damages caused by the past large-scale earthquakes. A series of studies were conducted to evaluate the effectiveness of the compaction method and other factors, if any, in sustaining a seismic force that is greater than the assumed one and caused no damage. Based on the results of these studies, the Architectural Institute of Japan (AIJ) has indicated in its “Recommendations for Design of Ground Improvement for Building Foundations” published in 2006 that the liquefaction resistance ratio (tl/sz) of the composite ground, which consists of sand piles and surrounding compacted ground, is higher than the RL calculated by using the SPT N-values of the ground in-between the sand piles. In this paper, statistical analysis of safety factor against liquefaction, FL, was performed by using the SPT N-values of ground in Port Island and Rokko Island which were both fully reclaimed islands in Kobe city during the 1995 Hyogo-ken Nambu Earthquake (classified as intense shaking) and, together with the consideration of relative settlement, resulted in tl/sz of the composite ground being 1.5~2.5 times of tl/sz of the soil in-between piles after improvement. Furthermore, the liquefaction resistance curve of SCP-improved sites obtained from the relationship between SPT N-values and cyclic shear stress ratio during the 2011 off the Pacific Coast of Tohoku Earthquake, which was regarded as long-duration earthquake, was plotted to the left side of the curve originally proposed by Japan Road Association. Thus, the liquefaction resistance of the improved ground was found to be higher than that of the natural ground, even for the same SPT N-values, verifying the validity of the AIJ recommendation.

Jan 1, 2017

By Alan D. Fisher

Amtrak made a decision to replace an aging bascule bridge with a vertical lift bridge for their crossing of the Thames River in New London, Connecticut. The new lift bridge occupies the same alignment and shares the same foundations as the bascule span. During construction the deep foundation caisson supporting the bascule span settled and tilted. Investigation into possible reasons revealed interesting historical facts, both of the construction of the innovative open well caisson foundations and of the state-of-the-art in tremie concrete placing methods in use at the turn of the century. This paper describes both of these topics.

Jan 1, 2013

By Parameswaran V. S, Anshuman Singh

This is a case study on ground improvement using Stone columns at Kokrajhar in Assam which comes under seismic Zone V as per IS: 1893. The strata at site comprised of mostly fine sands with low SPTN values, fine content less than 10% and ground water table (GWT) at shallow depth. As ground water table subjected to seasonal variation, water table is considered at ground level for designing purpose. The geotechnical profile of the boreholes was analysed on the guidelines of IS 1893 (Part 1) -2016 and it was observed that the liquefaction potential of the soil layers is prominent and ground improvement is inevitable up to a depth of 9.5 m below existing ground level. In order to mitigate the liquefaction of soil layer, Stone columns were proposed. The in-situ soil is densified using wet top feed vibroreplacement method with an area replacement ratio of 16%, so that the relative density of the soil can be enhanced to prevent liquefaction risk. Correlation between relative density, fines content and increment of SPT N –value given by Tokimatsu and Yoshimi (1983) was used for designing purpose. Field tests such as SPTs were carried out at site to validate the extent of SPT (N) improvement. Detail comparison of pre and post density, SPT N values and CRR values were discussed in this paper.

Nov 1, 2022

Jan 1, 2001

By Lance Rasband, Richard Hanke

"Seattle Tunnel Partners (STP) started mining on Seattle’s SR99 tunnel on July 30, 2013, working slowly through a 15 ft (4.6 m) thick fiber-reinforced concrete headwall. Once through the headwall, the machine would move through roughly 400 lineal ft (122 m) of jet grout-improved soil at a rate slightly over 6 ft (1.8 m) per day. It was anticipated that once through the improved area, Bertha—the world’s largest tunnel boring machine—would move at a rate of 35 ft (10.7 m) per day. By the end of October 2013, Bertha had mined roughly 430 ft (131 m), averaging 4.73 ft (1.4 m) per day, and had begun mining within native soils. By the start of December 2013, tunneling reached the 800 ft (244 m) mark and Bertha averaged 12 ft (3.7 m) per day, achieving as much as 42 ft (12.8 m) of progress on some days. However, on December 6, 2013, Bertha began to stumble and all progress quickly came to a halt. Preliminary InvestigationInitial reports stated that an obstruction had stopped the machine in its tracks. Malcolm Drilling received an early morning call on Sunday, December 8, 2013, from STP to rapidly mobilize a Bauer BG-50 drill rig with crews to investigate what was hindering Bertha’s progress. Malcolm’s equipment and crews flew into action and were completely mobilized and operational by mid-week. The preliminary investigation involved installation of 10 deep dewatering wells to reduce the hydrostatic head within the ground around the machine and allow STP personnel to inspect the cutter head from within the shaft for presence of obstructions. By the close of December 2013, the wells were installed and the dewatering system was fully commissioned. STP crews were then able to inspect the cutter head and found small fragments of a steel pipe wrapped around the outside of the shield. The steel was apparently from an abandoned 10 in (0.25 m) diameter monitoring well casing previously installed by WSDOT (Washington State Department of Transportation) to monitor groundwater conditions for the design and planning of this very project. After the steel was cut out of the head and cleared from Bertha’s path, she attempted to move forward but was only able to manage a slow crawl"

Jan 1, 2015

By Stefano Pirrello

"Sydney’s booming real estate market has pushed property developers to invest in historically “no-go” areas, which were previously too expensive to develop. These areas are usually near rivers where the sites are underlain by deep alluvial and estuarine sediments. In these ground conditions conventional bored pile techniques are often not competitive. Contiguous Flight Auger (CFA) and Drilled Displacement Piles (DD) techniques are on the other hand suitable for these ground conditions. This paper deals with the design and construction challenges encountered with these piling techniques for a series of high-rise towers in Sydney’s West. The advantages of DD over CFA piles such as reduced overall spoil with substantial cost savings and achievable rock sockets in medium strength bedrock are discussed. Design validation through interpretation of real-time data from the piling rigs’ on-board computer data, and low and high strain pile dynamic testing (PDA) is discussed. Testing data is presented as CAPWAP (Case Pile Wave Analysis Program) analyses for different concrete grades.INTRODUCTIONThe booming real estate market in Sydney has pushed property developers in investing in historically “no-go” areas, which were previously too expensive to develop. These areas are usually near rivers where the sites are underlain by deep alluvial and estuarine sediments. In these ground conditions conventional bored pile techniques are often not competitive. Contiguous Flight Auger (CFA) and Drilled Displacement (DD) Pile techniques are on the other hand suitable for these ground conditions and were utilised using concrete injection methods. This paper deals with the design and construction challenges encountered with these piling techniques for a series of high-rise towers in Sydney’s West.GEOLOGY & GEOTECHNICAL CHARACTERIZATION OF THE SITEThe Sydney 1:100 000 Geological Series Sheet shows that the site is underlain by man-placed filling and alluvial/estuarine sediment. The sediment comprises silty to peaty sand, silt and clay. Shell layers are also expected to be present within the soil profile. The Prospect/Parramatta River 1:2500 Acid Sulphate Soil Risk Map shows the site as ‘Disturbed Terrain’ in which soil investigations are required to assess acid sulphate soil potential. Several Cone Penetration Tests and Boreholes were carried out during the geotechnical investigation. All boreholes were extended to bedrock and NMLC-sized diamond core drilling was used to obtain 50mm continuous core of the rock, enabling unconfined compression strength testing to be carried out on selected samples. A summary of the ground conditions encountered on this site and inferred from the CPTs can be described as follows:"

Jan 1, 1900

By Han Jie

The results of full scale plate load tests on stone columns on soft clay in coastal areas are presented in this paper. Four load tests were made, two of which were performed on the ground treated with stone columns, one on an isolated stone column and the last one on the untreated ground. For a given stress range, the settlement of the rigid plate, the stress concentration factor, and the excess pore water pressure were measured. It is found that the distribution of vertical stress beneath the rigid plate supported by the composite ground of stone columns is very different in shape from the one by the untreated ground, that the stress concentration factor has a relation with the stress level and time, that the stone columns increase the bearing capacity up to by 2 times, and that the ground stabilized by stone columns is of great advantage to keep the foundation stable.

Jan 1, 1991

By Babak Mamaqani

The Regional Connector Transit Corridor (RCC) is the Los Angeles Metro area's ambitious light rail project, running under the city's main thoroughfares, Flower and 2nd streets. When com- pleted, it will alleviate traffic and parking congestion downtown, while connecting thousands of residents living in the bedroom communities of Inland Empire and Long Beach to their jobs there. The rail line of 1.9 mi (3 km), which involves a $1.756 billion (€1.545 billion) budget to construct the under- ground rail line, including three new stations. They are the Grand Av Arts/Bunker Hill station at 2nd and Hope streets, Historic Broadway Station at 2nd Street and Broadway, and Little Tokyo/Arts District Station at 1st Street and Central Avenue, which will offer riders their first "one seat/one fare" ride option from Azuza to Long Beach. Regional Connector Constructors JV is led by Skanska USA Civil West California District Inc. (Skanska), in partnership with Traylor Bros., Inc. (Traylor), to deliver RCC to the Los Angeles County Metropolitan Trans- portation Authority (Metro). PB&A was the structural engineer of record (SEOR) responsible to design the shoring systems for the Grand Av Arts/Bunker Hill Station at 2nd and Hope streets, and Historic Broadway Station at 2nd Street and Broadway. The temporary shoring design for Historic Broadway Station is the focus of this article, and why the project received special recognition as a runner up for DFI's 2021 Outstanding Project Award. Two main challenges are discussed in particular: design of the shoring system considering all construction stages, and design of an underpinning system where the Los Angeles Times Building (Times Building) protruded into the station footprint.

Apr 1, 2022

By Roberto A. Lopez, Eric Lindquist, Jon Bussiere, Dean Iwasa

"The new 11-story U.S. Federal Courthouse building in downtown Los Angeles demanded a cost effective foundation system capable of attaining a strict total settlement criterion of 0.5 inches (12 mm) under high applied loads. A design-build ground improvement system consisting of 3 ft (0.9 m) and 7 ft (2.1 m) diameter deep soil mix (DSM) columns embedded into the relatively soft Fernando Formation bedrock was selected for the project. The DSM columns support applied stresses of up to 8,800 psf from four large concrete core elements that transfer concentrated building loads to a 3 to 6 ft (0.9 to 1.8 m) thick reinforced concrete mat. The soil mixing ground improvement solution provided flexibility by allowing installation of the DSM columns around existing belled caissons left in place from prior structures, and by allowing repositioning of some of the DSM columns to avoid other existing obstructions in the fill. DSM spoils were used to construct a 2 ft (0.6 m) thick load transfer platform on top of the DSM columns. Quality control measures included utilizing equipment outfitted with automated data acquisition systems, performing three full scale load tests, performing daily wet-mix sampling and compression testing, performing full-depth coring and unconfined compression testing on core samples, and using a borehole acoustic televiewer to evaluate the uniformity of the DSM columns where core recovery was problematic. The results of subsurface investigation and the load tests were used to develop 3-dimensional finite differences models for evaluating stress distribution and deformation of the foundation system.INTRODUCTIONThe new U.S. Federal Courthouse building is currently under construction in downtown Los Angeles, California. The new courthouse will be 11 stories tall with one partial below-grade B1 basement level. The building will have four structural core elements that extend from the main building foundation at the B1 level to the top of the structure. The majority of the building loads will be transferred through the structural core elements to a new 3 to 6 ft (0.9 to 1.8 m) thick reinforced concrete mat beneath the central portion of the structure. The foundation pressures beneath each of the core element locations will be approximately 6,200 to 8,800 psf (300 to 420 kPa) with lower foundation pressures at locations farther away from the central core area."

Jan 1, 2015

By Soorkty Elarabi

The aim of this paper is to discuss the impact of end bearing plate on the capacity of micropile. Preliminary studies have been made in Sudan in specific area of cohesive soil. Experimental works were carried on a number of micropiles with and without end bearing plate. Same diameters, lengths and techniques of placing cement grout are considered, there after the axial load test applied to find out the capacities of micropiles in both cases. Deduced results in each case show that the end bearing plate has no positive impact on micropile capacity.

Oct 1, 2022

By Jon Huff, Jeffrey Donville, Hannah Iezzoni, Dan Stevenson

Occasionally, in the design of deep foundations for a structure, a single deep foundation element may be used to support a building column. The most common type of element used in such cases is a drilled shaft (also referred to as a drilled pier, caisson, or bored pile). However, as installation capabilities have improved, large diameter augercast piles are increasingly more common. While drilled shafts and augercast piles differ significantly in construction methods, in the eyes of the International Building Code (IBC), both are treated as cast-in-place deep foundations and must comply with many of the same code provisions. Deep foundations are required to be braced such that lateral stability is provided in all directions, however isolated, cast-in-place elements that have a diameter (D) of at least 2-feet and a length (L) not more than 12 times the diameter can be an exception. In response to the concerns raised by some member professionals, the Deep Foundations Institute’s (DFI) Augered Cast-in-Place Pile and Drilled Displacement Pile Committee took a closer look at the code and its applications, the historical development of the code language through the years and performed analytical modeling to evaluate the impact of this ratio on a pile’s stability. The question is whether the limiting ratio included in the IBC 2018 code provisions is justified, or whether different criteria should be used to determine when isolated deep foundation members are allowed.

Sep 8, 2021

By Chandrasegaran, Tamilmani

"This paper describes a case study of a retaining wall structure using a diaphragm wall to construct a stilling basin at Tanjung Bin T4 power plant in Johor Bahru, Malaysia. The stilling basin is part of the Phase IV (T4) 1x1000MW power plant’s offshore cooling water discharge culverts. The site is located close to the sea with 5m of fill on top of very soft sediments of marine origin up to 20m thick underlain by fluvial clay and metasedimentary rock. Stringent wall deflection criteria and construction program dictated adopting an efficient solution with 800mm thick diaphragm wall supported by permanent top support as the temporary prop and improved horizontal restraint provided by deep mix piles acting as a slab (ground improvement layer) below the final excavation level. The depth of excavation is about 10.12m from the existing ground level. The proposed solution kept the wall deflection below the limit of 0.7% of the depth of bulk excavation and avoided additional props leading to faster completion of the structure. With unsymmetrical loading behind the retaining walls, 2D finite element analysis was carried out to assess the wall deflection and stresses in the wall and the grout layer below. The diaphragm wall is instrumented to monitor the behavior and the findings are discussed in the paper.INTRODUCTIONConstruction in soft marine clay has always been a challenge to the engineer because of its very low shear strength and its sensitivity to disturbance. In the case of excavation projects the problem becomes even more complicated with development of excess pore pressure during excavation. Marine clay with its low shear strength and lesser passive resistance, generally leads to large wall movements and settlement behind the wall. Increased passive resistance coming from increased number of props is useful but has its limits and it is no longer the most effective way in containing or reducing the wall movements or forces in the wall. One of the solutions to these problems is to improve the soil shear strength by means of ground improvement infront of the wall at an elevation most appropriate to maximize wall performance. There are several methods adopted in improving a soil layer including mixing additives to the ground to improve the shear strength to partially replacing the weak soil while others are fully replacing the weak soil. This paper discusses the case study of approximately 10m of excavation in soft marine clay using 800mm thick diaphragm wall supported by Deep Mix Piles (DMP) being used to improve soft marine deposit to form a slab just below the formation level and thus improving passive resistance significantly. The ground improvement layer helped to reduce the wall forces and deflections making it possible to remove the need for additional temporary props leading to significant savings is time and productivity. The paper presents the various options explored before this method is adopted, the design approach, instrumentation data and the monitored results."

Jan 1, 2015

By Michael Moran

Typical ACIP Pile Rig [ ] Hollow Stem Auger ? Continuous flight auger ? 3 inch inside diameter pipe ? Auger diameters: 12, 14, 16, 18, 20, 22, 24, 30, and 36 inches ? Auger section lengths: 4, 5, 10, and 20 ft ? Weight ranges from about 70 lbs per ft for 12 inch to 120 lbs per ft for 24 inch and 200 lbs per ft for 36 inch

Jan 1, 2005

By Mu Chen, Ye-Shuang Xu, Dong-Wei Hou, Shui-Long Shen, Huai-Na Wu

"This paper presents a laboratory investigation on the mechanical behaviors of the cement-clay admixture improved by polypropylene fiber. Cement can significantly improve the clay admixture. The fiber additive also improves the strength and ductility of the improved clay. The Unconfined Compression Strength (UCS) of the polypropylene fiber-reinforced cement-clay presents an overall trend to grow with the increase of fiber length. The improved clay reached its peak strength at the fiber content of 0.5%. Then the UCS of the improved clay will slowly reverse if the fiber content continues to rise. For study of curing time, improved clay behaves better in its early strength, but an inhibition will be brought about if fibers are excessive.INTRODUCTIONGround improvement technology is essential for construction of structures in soft ground. Some traditional techniques often cost much but result in little. For instance, along the coastal region of China, soft ground is often improved by backfill with high quality sandy soil transported far away, leading to high additional haulage costs and long construction period. Reutilizing the excavated soil as backfill or subgrade after treatment, by contrast, will be more economical and effective (Hufenus et al., 2006). Many researches have been conducted to improve the compression strength of soft soil, among which, the method of mixing the soft soil with cement and fly ash is one of the most common ways (Kolias et al., 2005; Horpibulsuk et al., 2009; Porcino et al., 2012). It is known that soil resists well against compression and shear force but behaves poorly in resistance to tension. Therefore, utilizing tensile elements such as fibers and strips to improve the tensile strength will be effective because of its strength isotropy, better durability and cost effective (Haeri et al., 2000; Kaniraj and Havanagi, 2001; Consoli et al., 2010)."

Jan 1, 2015

By Timothy C. Siegel

Given that piles are composed of different materials and installed using a variety of methods, ASTM D 1143/D 1143M-07 Standard Test Methods for Deep Foundations Under Static Axial Compression is justifiably general so that it has as many applications as reasonably possible. There are aspects of the test setup, the test procedures, and data interpretation for instrumented piles (some of which are specific to augered cast-in-place piles) that are either not discussed in detail in this ASTM standard or are not addressed at all. Specifically, the use of variable time hold times can obscure the shape of the conventional load-deflection curve, as well as, influence the interpretation of the ultimate pile capacity. Unload-reload cycles induce additional non-uniform internal axial loads within the pile which complicate interpretation of the strain gage data and increase the potential for errors. Attempts to maintain a constant top load during the hold period can lead to operational difficulties in taking measurements and are technically unnecessary. Residual load has been shown to develop in cast-in-place piles and can significantly influence the axial load distribution as interpreted from strain gage data. The stiffness of cast-in-place piles has been observed to vary with the measured strain, and a constant modulus, as provided by correlation with the unconfined compressive strength of the grout, may lead to a significantly different interpretation of the axial load distribution.

Jan 1, 2010

By Peter Cali, David Yang, Rakshya Shrestha, Ralph Griffin, Sushil Kafle, Motoji Watanabe

"As a part of the ‘US Army Corps of Engineers - New Orleans to Venice, Louisiana Hurricane Protection Project’, deep mixing ground improvement was designed to reinforce the soft ground for the emergency repair of a 7297-foot (2,224 m) long section of the Mississippi River West Bank levee in Buras Levee District under the contract ‘Emergency Levee Repairs – Contract P-17A, Plaquemines Parish, Louisiana’. The ground improvement utilizes a series of soil-cement panels oriented in the transverse direction of the levee. Each soil-cement panel consists of overlapped columns installed by the deep mixing method (DMM). DMM is performed from the existing top of levee and extended to competent stratum at depths varying from 26 feet (7.9 m) to 47 feet (14.3 m) below the working platform. The main purpose of the DMM panels is to provide shear resistance to the levee against lateral loads at high flood water condition. The DMM panels support the additional vertical load created by the increased height of the levee for hurricane protection and control the long-term settlement of the remediated levee, which might otherwise occur due to the compression of soft foundation soils. The total amount of DMM treatment is approximately 54,000 cubic yards (41,500 cubic meters). This paper reviews the project background, subsurface soil conditions and presents the design, construction and quality control of the deep mixing work for this levee repair project.INTRODUCTIONIn August 2005, Hurricane Katrina caused major damage to the federal and non-federal flood control projects in southeast Louisiana. In September 2005, Hurricane Rita caused further damage to this flood protection system. In an effort to minimize further damage and to enhance the protection level, certain non-federal levees located on the west bank of the Mississippi river in Plaquemines Parish, Louisiana were incorporated into the New Orleans to Venice Hurricane Protection project by the US Army Corps of Engineers (USACE). DMM techniques were then utilized by the USACE in several of these emergency projects and in many medium sized projects between 2006 and 2010 (Bruce et al. 2012). This project (called P-17A hereafter) which forms a part of this protection system is executed under the contract Emergency Levee Repairs, Contract P-17A. This is one of the largest projects of the USACE after LPV- 111. The huge LPV-111 project (5.5 miles (8.9 km) of levee) treated by DMM), the largest DMM project ever conducted outside Japan, began in 2010 and was completed in 2012 (Cali et al. 2012, Bruce et al. 2012).DMM is utilized at P-17A to construct a series of soil-cement panels oriented in the transverse direction of the existing levee to provide shear resistance to the levee against the lateral load during high flood water condition. The project extends 7297-foot (2,224 m) along the West Bank Levee of the Mississippi River in the Buras district of Louisiana, parallel to Louisiana Highway 23 (LA-23) as shown in Figure 1. It is located approximately 60 miles (96 km) south-east of downtown New Orleans."

Jan 1, 2015

By Amr Sallam, Ahmad Mohamed, Mohamed Alrowaimi

Renewable energy, in the form of wind and solar, has emerged as main source of energy in the modern society. The wind industry has substantially grown over the last two decades to become a key player in providing energy to public. Wind turbines are getting larger, taller, and more efficient every year. The foundation is a major component of the wind turbine system. The wind turbine foundation must provide short and long-term stability for the overall turbine to allow continuous and safe turbine operation for energy production. The turbine serviceability and stability requirements must be geotechnically and structurally satisfied. In North America, major foundation types currently utilized in the wind industry include gravity spread foundation, mono pier foundation, and pile foundation. In this case study, a Post Tensioned Pile Cap (PTPC) foundation was used to support a 3.15-3.4 Megawatt turbine with 125M Rotor supported on 87.5M-hub-height tower. Soil anchors in the form of Auger-Pressure-Grouted-Displacement (APGD) piles and Continuous Flight Auger (CFA) piles were utilized. Four distinct subsoil conditions were identified, and for which four pile designs were adapted. Due to the occasional encounter of stronger soils at 50 to 55 feet (15.2 to 16.7 m), shorter pile design was preferred. To satisfy the design uplift load, pile post grouting were utilized to increase the shaft capacity of the piles. In this paper, the pre-production pile load test program will be described. The pile load test procedure, analysis, and results will be presented. A discussion will be provided, which led to the selection of the optimum pile design to support the high tension loads taking into consideration pile length limitations.

This manual is limited to Augered Cast-in-Place (ACIP) piles constructed using a hollow stem continuous flight auger. 1.1SCOPE AND LIMITATIONS The intent of this manual is to provide guidelines for observing and documenting the installation of ACIP piles. The manual may also serve as a guide for the training of inspection personnel. It is expected that the general guidelines and procedures described in this manual for the inspection and installation of ACIP piles will be supplemented by engineering judgment, local practice, and experience. ACIP pile construction procedures will vary depending on soil, rock, and groundwater conditions. This manual represents a wide range of possible applications in a variety of projects. It is not intended to be applicable in all situations nor replace engineering judgment for any given project. Therefore, an all-inclusive inspection manual is not considered practical or desirable. This manual should not be used to interpret or replace project specifications. It has, however, been prepared to complement the Augered Cast-in-Place (ACIP) Piles Manual model specification (DFI, 2003).

Jan 1, 2010