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By R. K. Filip

"Steel bearing piles have long been used to carry high compressive, tensile and lateral loads. Such piles are most commonly tubular or ""H"" profile and are typically installed using percussive techniques. The noise and vibration associated with such installation techniques tends to preclude the use of steel bearing piles in urban and other sensitive areas.This paper describes the design and construction of an innovative new road bridge in Milton Keynes, UK. The steel bearing piles were required to continue out of the ground to form the bridge columns and abutments and then be cast directly into the soffit of the reinforced concrete bridge deck. This project was to be the first time in the UK, that this form of bridge design had been used.The paper shows how new installation techniques allowed the designers to use these high capacity steel elements in a sensitive urban environment without the use of percussive or vibratory installation techniques. Finally the paper shows how these quiet and vibration-less installation techniques can be extended to other applications.A UNIQUE BRIDGE SUPPORTED ON ""BOXED SHEET PILES""CONCEPT HISTORYThere are over 700 bridges in Milton Keynes. Concrete is the dominant construction material, most are single span with massive parallel wing wall retaining abutments. All have a certain uniformity of aesthetic design. Pell Frischmann Consultants Ltd (PFC) proposed to the client, English Partnerships (EP), that an ""integral bridge"" with a slender open appearance would be an appropriate aesthetic form for a new highways bridge, within the district of Westcroft (figure 1). The concept required that the bearing piles be continued up out of the ground to form the bridge columns and abutments. Four rows with four piles in each row were suggested. Each would then be cast directly into the reinforced concrete bridge deck forming a moment connection (figure 2). This concept meant that a single continuous steel structural member would replace traditional reinforced concrete bored piles, pile caps and piers. This member would carry vertical and lateral loads. The conceptual design was intended to meet the following client requirements:"

Jan 1, 2005

By David S. Graham, Joseph D. Bailey, Paul J. Axtell, Michael K. Muchard

"Two instrumented test piles were simultaneously subjected to a static lateral load test by jacking the piles apart. One of the piles was loaded in axial compression via kentledge during the lateral load test. Both piles were constructed in an identical manner. These piles were constructed and tested as part of a construction-phase load test program for a floodwall improvement project along the Missouri River in Kansas City, Kansas. Details of the subsurface conditions, drilled pile construction, instrumentation, and load testing procedures are described. Data collected during testing of the piles are presented and compared. Potential effects of the axial compressive load related to observed differences in pile lateral response are discussed.INTRODUCTIONTwo instrumented test piles were simultaneously subjected to a static lateral load with one of the piles also subject to a combined axial load during testing. The load test program was part of a floodwall improvement project in Kansas City, Kansas. Known as the BPU floodwall, the floodwall runs along the south bank of the Missouri River at a Kansas City Board of Public Utilities power generation and water treatment facility. The project location is shown in Fig. 1.Drilled, 2-ft (610-mm) diameter piles were designated by the designer, the U.S. Army Corps of Engineers (COE), as the foundation type for supporting extended floodwall footings. The drilled piles are fully cased, cast-in-place concrete, reinforced with a steel 12x74 (310x110) H-pile. In order to test soil lateral response and pile structural response under combined loading, the COE required that both a lateral test and combined lateral and axial test pile be constructed and tested. In order to most efficiently test both piles and to allow for simpler comparison, the two piles were simultaneously laterally loaded by jacking the piles apart, applying a maximum lateral load of 195 kips (867 kN). A constant axial load was applied to the combined test pile by kentledge prior to lateral loading and was maintained for the duration of the lateral load test. The total weight of the kentledge was 61.5 kips (274 kN). Fig. 2 shows the test setup."

Jan 1, 2017

By KeerthiRaaj Subrmanian, Muthukkumaran Kasinathan

"A railway embankment is under construction between Nagapattinam to Thiruthuraipoondi covering 36.5 km. The sub-soil strata comprises of soft clay extending up to 10 m below existing ground level, which is subjected to stability and settlement problems. A trial stretch covering about 5 kilometer was improved using Prefabricated Vertical Drains (PVD) with surcharge was recommended to accelerate the consolidation settlement. The geotechnical characteristics of the subsoil are examined through laboratory tests on representative soil samples. Recent improvement in the finite element analysis has facilitated modeling of PVD in finite element software for computing the settlement magnitude and time rate of consolidation. In this study the theoretically predicted settlement magnitude and time rate of consolidation from Terzaghi.s vertical consolidation, Barron's radial consolidation are compared with the analyzed FEM results for both the cases with and without PVD improved embankment. The comparative analysis between FEM and predicted data hold good for stresses and the associated deformations. The excess pore water pressure was significantly lower and their dissipation was faster in case of embankment with vertical drains. Thus PLAXIS 2D tool shows fairly convincing results in comparison to the theoretical solutions.1. INTRODUCTIONFrom the earlier times civilization has been developed in a fashion either at the banks of river or near to the shore region, because of the easier availability of food and water. This over centuries made them as huge cities, consequently population rise made the increased necessity of highway, railways, port and even more ground for construction. As a stake researchers are pushed to make a low bearing ground into a massive carrier of skyscrapers, embankment, bridges etc. These low bearing ground suffers from total and differential settlement, slope instability. Hence, numerous ground improvement techniques were followed to eradicate these concerns which include preloading, piling, stone column, vertical drains and geosynthetic reinforcement. Among them Prefabricated vertical drain (PVD) are often used to accelerate consolidation of soft subsoil and has been the main soil improvement method used in improving the soft marine clay deposit (Chu et al.(2004); Chai (2001) and Arulrajah et al.(2003)). Literature review of embankment over soft clay deposit reveals that combination of PVD with preloading is widely considered as an economical and less time consuming ground improvement technique."

Jan 1, 2015

By Peter Faust

"The south access road to San Francisco’s Golden Gate Bridge, known as Doyle Drive or Presidio Parkway, needs to be replaced. Built in 1936, it is the primary highway and transit linkage through San Francisco between counties to the north and south. The roadway is tucked into the natural contours of the Presidio and the Golden Gate National Recreation Area, one of the nation’s largest urban parks.The old steel truss structure will be replaced by a new concrete cast-in-place bridge. The foundation design of the new bridge is based on drilled mono shafts below each bridge column. Most shafts required large diameter permanent steel casing installed under strict vibration limitations since several historic landmarks are near the project alignment. Malcolm Drilling decided to use the largest oscillator in the world to install the piles.The area occupied by the Presidio is generally hilly, sloping down northwards to San Francisco Bay. In the western half of the project route, two bluffs rise steeply to about 80 ft (25 m). The bluffs are separated by a valley 60 ft (18 m) deep and 1,500 ft (457 m) wide, which is spanned by the old and new bridge. Overburden soils in this valley are made up of artificial fill, slope debris, ravine fill and Colma Formation, a fine to medium-grained sand unit with clay beds. The Bay Muds encountered in the project area are typically soft clayey silts, becoming medium stiff with depth.The basement rocks underlying the overburden belong to the Franciscan Formation, described as shale, sandstone, serpentine and greywacke, it is extremely variable in hardness, fracturing and weathering. The material can vary from very hard to very soft, can be slightly to very intensely fractured and almost not weathered, to totally decomposed within relatively short distances both laterally and vertically. Rock strength can vary from too weak to be tested to serpentine layers with unconfined compressive strength of 15,000 psi (103MPa) or higher. Groundwater levels in the area are typically no more than 10 to 20 ft (3 to 6 m) below the ground surface."

Jan 1, 2012

By Mikael Calando, Thomas Joussellin

"San Francisco's rapid growth has caused the city to plan for the Transbay Transit Center Project, a visionary transportation and housing project, that will transform downtown San Francisco and the San Francisco Bay Area’s regional transportation system by creating a “Grand Central Station of the West” in the heart of a new transit-friendly neighborhood that will be home to more than 20 new towers rising a high a 1,070 ft. This paper describes the specificities of using advanced diaphragm wall technology, tooling, equipment and installation practices for deep foundation and permanent underground structures. In particular, this paper will emphasize on the urban constraints, geotechnical conditions, and the novel approaches adopted for the construction challenges of the Transbay Transit Center’s Load Bearing Elements, or Barrette PilesPaperThe Transbay Transit Center Project consists of the construction of a new multimodal, five-story Transit Center located in the South of Market neighborhood near the Financial District in San Francisco. The future Transit Center will incorporate nearly 83,000 square feet of retail, a 5.4-acre rooftop park, an extensive public arts program and bus ramps that will connect the Transit Center to a new off-site bus storage facility and the San Francisco–Oakland Bay Bridge. The new facility will accommodate more than 100,000 passengers each weekday and up to 45 million per year. Additionally, the new Transbay Transit Center will replace the since-demolished San Francisco Transbay Terminal, and nearly 20 towers, such as Salesforce Tower, will take advantage of the height increases allowed through the Transit Center District Plan.The approximately $4.5 billion project features a new five-story structure (including two underground stories) and new bus ramps which include a cable-stay bridge. The deep foundations for the pylon of the bridge (Pylon 9) consist of two each 21 ft x 5 ft barrettes (also called Load Bearing Elements in the US) extending more than 180 feet below grade and 10 feet into the bedrock. The barrettes were chosen because of the combination of high loads, significant depth and small footprint. The barrettes are installed using the Diaphragm Wall technology. Nicholson Construction was contracted by Shimmick Construction to install the cable-stay bridge’s foundation elements."

Jan 1, 2016

By Pierre Gouvin

"This paper discusses real time monitoring of utility vaults during the reconstruction of the Elliot Bay Seawall in Seattle. The project, undertaken because deterioration of the old wall posed increasing risks to property and lives, impacts businesses, ferry terminals, a rail line, and electrical utilities that distribute power to much of the downtown area. The project, which has been fast tracked to minimize risk and commercial impacts, involves multiple contractors with heavy machinery working in an area one mile long and only a few hundred feet wide. This presented challenges to monitoring of the utilities, as will be discussed in the paper.INTRODUCTIONThe Elliot Bay Seawall (EBSW) was built in over a period of 18 years, starting in 1916. It consisted of a vertical concrete wall placed on a timber pilings and timber relieving platform. The seawall also retained fill that served as the foundation for a road known as the Alaskan Way. The seawall has performed well over the years, but now cracks in the concrete have allowed loss of fill, and the timber piles and support structures have been weakened by marine boring insects.The project to replace the seawall was undertaken because deterioration of the old wall posed increasing risks to property and lives. Because the project impacts businesses, tourism, ferry terminals, and a rail line, it was given a compressed timeline - 36 months from start to finish. In addition, construction activities have been staged carefully to minimize disruption of Salmon and other wildlife living in Puget Sound. In fact, will incorporate several habitat improvements to promote sea life, such as a nature-imitating textures in the surface of the wall and a glass deck structure that allows sunlight to reach the water. (Fig. 1) shows a schematic of the planned new wall.The sheet piling, concrete piles, jet grouting, drilled shafts, ground freezing, and demolition activities are all taking place in the narrow corridor that holds the subsurface ducts and vaults protecting Seattle’s electrical power distribution. If the network of duct bank and vaults were to experience differential settlement during work here, then most of downtown Seattle would be in the dark. Thus it was important to provide real-time displacement monitoring of these utility structures."

Jan 1, 2017

By Arash Khosravifar

One of our research thrusts at Portland State University (PSU) centers on developing design guidelines for pile foundations in liquefiable, laterally spreading grounds. This research has been primarily sponsored by the DFI Committee Project Fund (CPF) program through four awards, totaling nearly $240,000 in financial support. DFI contributed half of this financial support, while the other half was contributed in-kind by PSU and DFI Project Advisory Board members. Leveraging the CPF funds, we secured an additional $550,000 in financial support from the National Science. Foundation (NSF), which has enabled our research group to continue exploring this topic and contributing to the broader engineering community's understanding of the behavior of pile foundations in liquefiable soils. The CPF funds have fostered collaborations with practitioners and researchers beyond PSU. Notable examples include collaborative research involving data from five large-scale centrifuge tests on pile-supported wharves by Steve Dickenson, Ph.D., New Albion Geotechnical; Nason McCullough, Ph.D., Jacobs Engineering and Scott Schlechter, Geotechnical Resources, as well as 1-g shake table tests of bridge pile shafts conducted by Professors Ahmed Elgamal, Ph.D., and Ahmed Ebeido, Ph.D., of the University of California, San Diego. In addition to these collaborations, our research has benefited from industry-university partnerships formed through the involvement of DFI Project Advisory Board members. Their support and feedback ensure that our research products are practical and imple- mentable in real-world projects. The impact of the CPF funds extends to supporting graduate students' theses, which were the basis for 17 technical publications. Some of these publications are expected to have a significant impact on the industry. For instance, our 2018 DFI Journal paper, co-authored by former master's student Jonathan Nasr, cur- rently with the Army Corps of Engineers, has been cited in the 2022 British Columbia Supplement to Canadian Highway Bridge Design Code S6:19. A noteworthy product of our study is a step-by-step design procedure for pile- supported wharf structures subjected to the combined effects of lateral spreading and inertial loads, outlined in a 2022 American Society of Civil Engineers' (ASCE) Journal of Geotechnical and Geo- environmental Engineering paper co- authored by former doctoral student Milad Souri, Ph.D., PE, Geotechnical Resources.

Nov 1, 2023

"This model specification includes sample text shown in normal font with commentary in italics. The commentary is intended to highlight project-specific items the specification writer should consider during development of the specification. In some sections, typical values are presented to indicate common practice, and these values may be changed to reflect project-specific requirements. The commentary should be removed before using the specification for a project. 1. SCOPE The work consists of designing, furnishing, installing, and testing helical piles used to support foundation loads (compression, tension and lateral), and any ancillary materials (e.g., load transfer devices, etc.) according to the project plans provided and these specifications. Unless otherwise noted, the installing contractor shall provide all labor, tools, equipment and materials necessary to install the required piles. The parties referred to in this specification are as follows: • The Owner is the property owner. • The Owner’s representative is the individual or firm hired by the Owner to design and oversee the overall project. • The pile designer is the individual or firm generally hired by the installing contractor to design the helical piles. • Installing contractor installs and tests (if necessary) the helical piles, and possibly tasks associated with the project. It is important to clearly define the roles and responsibilities of every party on each project to promote good communication and reduce potential for contractual misunderstandings. Different types of contractual vehicles (design-build, value engineering, etc.) require different roles and responsibilities for the various parties, which should be considered in specification development. The Owner will provide suitable access to the construction site for the installing contractor’s personnel and equipment. Unless specifically noted otherwise in the contract documents, the Owner will remove and replace any structures, utilities, pavements, landscaping or other surficial improvements in the work area as necessary to facilitate the work. The Owner will be responsible for overall construction oversight to minimize potential for developing unsafe conditions. The work may include post-construction monitoring of pile performance if required by the Owner or the pile designer to confirm performance of the piles subsequent to their installation. The work may also include installation of additional piles if the initial installation does not meet specified capacity or performance requirements. Responsibility for providing subsurface investigation shall be addressed in the bid documents. The Owner is responsible for providing to the installing contractor all available subsurface soils, rock and groundwater information and geotechnical testing data."

Jan 1, 2015

By Ana Pereira, Naomi Norris, Donald Bruggers

The city of Christchurch, New Zealand is predominantly founded on alluvial sediments consisting of interbedded layers of loose to medium dense sand, soft to stiff silt and clay mixtures, and pockets of organics. These soil deposits have high liquefaction potential. Following the 2010/2011 Canterbury Earthquake Sequence several ground improvement trials were undertaken within Christchurch to understand the effectiveness of different types of ground improvement in these silty sand geological conditions. This paper presents a discussion of a stone column ground improvement trial undertaken at a Christchurch site with high fines content soils. Stone columns were installed using two types of installation methods and a range of Area Replacement Ratios (ARR) to assess the effectiveness of these ground improvement methods in high fines content soils as well as the influence on the type of installation method. Pre- and post-column installation CPTs, seismic Dilatometer Tests (sDMTs), cross-hole shear wave velocity tests, and plate load tests have been undertaken to assess the effectiveness of the ground improvement. Results of the testing are presented in this paper. INTRODUCTION This paper presents the results of a stone column ground improvement trial undertaken in Christchurch, New Zealand (Fig.1). In 2010 and 2011, four large earthquakes (greater than magnitude 5.9) and thousands of smaller aftershocks occurred in the greater Christchurch region. These events are referred to as the Canterbury Earthquake Sequence (CES). Liquefaction occurred across large portions of the city during the stronger earthquakes, particularly the February 2011 event. Following the CES a large amount of data was collected across the city including the location and volume of sand boils, and the location and magnitude of ground cracks. Additionally, data from thousands of ground investigations have been uploaded into a public database. As a result, there is clear evidence that silt and silty sands liquefy in addition clean sands. The CES and resulting liquefaction motivated a series of studies and trials from different organisations aiming to better understand the available technologies for liquefaction mitigation. The subject of this paper is a ground improvement trial undertaken by a local contractor specialising in deep foundations and ground improvement. They were interested in understanding the effectiveness of stone column ground improvement in high fines content (silty) soils using two different installation techniques, vibratory and non-vibratory. Different arrays and Area Replacement Ratios (ARRs) were used for each of the two methods of columns installation.

Jan 1, 2019

By Tony Suckling

"As we head toward the United Nations Climate Change Conference in Copenhagen in December, the environment and sustainability will become headline news for a while. Governments are expected to agree to a set of binding targets to reduce carbon emissions probably before 2020, and certainly before 2050. This will, in effect, initiate a low carbon economy in many parts of the world. Sustainability has mainly been rhetoric so far, the exceptions being projects for those looking to the long-term future and not for short-term financial gains.The probabilities and consequences of negative impacts on the environment and on society over the short term and in the long term can be assessed and mitigated, but mitigation often adds cost. Also, we cannot know what technologies will be available, say 1,000 years into the future, which is about 40 generations of our society. It is easier to have a connection with 100 years into the future, which is only about 4 generations. Individuals may have a different sense of sustainability, and place a different value on mitigation, its cost, its importance and its potential impacts.Sustainability means different things to different parties on a construction project. For example, a land developer is likely to have a different view on the design in terms of sustainability than that of the designer. The developer may also likely to be more interested in sustainabiliy if there are tangible economic benefits that might accrue. Achieving sustainability on any project, leads to conflict between competing interests or demands cooperation between the economic and technical sectors involved. The foundations for a building or bridge, by definition, need to interact with the ground whose behaviour cannot be dictated by man. The aims of sustainability are the same as for the building or bridge, both of which are constructed of manmade materials, but it is less clear how they should be achieved. An example is the driven pile that does not produce spoil waste, but is likely to be too noisy to be acceptable in an urban environment. This then begs the question, should the public accept the nuisance of short-term pile driving to achieve a more sustainable foundation? Additionally, the question has to be asked, can the deep foundations industry develop its techniques and products to help make them more acceptable and appropriate more often than is possible now?"

Jan 1, 2009

"This model specification includes sample text shown in normal font with commentary in italics. The commentary is intended to highlight project-specific items the specification writer should consider during development of the specification. In some sections, typical values are presented to indicate common practice, and these values may be changed to reflect projectspecific requirements. The commentary should be removed before using the specification for a project.1. SCOPEThe work consists of designing, furnishing, installing, post-tensioning and testing helical anchors used to support tension loads, and any ancillary materials (e.g., load transfer devices, etc.) according to the project plans provided and these specifications. Unless otherwise noted, the installing contractor shall provide all labor, tools, equipment, and materials necessary to accomplish the work. The parties referred to in this specification are as follows:• The Owner is the property owner.• The Owner’s representative is the individual or firm hired by the Owner to execute project tasks required for the successful design and construction of the overall project. Tasks could include construction management, design, oversight, etc.• The anchor designer is the individual or firm generally hired by the installing contractor to design the helical anchors.• Installing contractor installs and tests (if necessary) the helical anchors, and possibly other tasks associated with the project.It is important to clearly define the roles and responsibilities of every party on each project to promote good communication and reduce potential for contractual misunderstandings. Different types of contractual vehicles (design-build, value engineering, etc.) require different roles and responsibilities for the various parties, which should be considered in specification development.The Owner will provide suitable access to the construction site for the installing contractor’s personnel and equipment. Unless specifically noted otherwise in the contract documents, the Owner will remove and replace any structures, utilities, pavements, landscaping or other surficial improvements in the work area as necessary to facilitate the work. The Owner will be responsible for overall construction oversight to minimize potential for developing unsafe conditions. The work may include post-construction monitoring of anchor performance if required by the Owner or the anchor designer to confirm performance of the anchors subsequent to their installation. The work may also include installation of additional anchors if the initial installation does not meet specified capacity or performance requirements. Responsibility for providing subsurface investigation shall be addressed in the bid documents. The Owner is responsible for providing to the installing contractor all available subsurface soils, rock and groundwater information and geotechnical testing data."

Jan 1, 2016

By G. L. Sivakumar Babu, P. Chaithra

"Raft foundations which are used against differential settlements and for carrying heavy loads can still be subjected to excessive settlements even if it is safe against bearing capacity consideration. Providing additional piles under the raft can reduce such settlements to acceptable values. In addition to settlements, the piles also relieve the raft a part of the total load and thus the bearing capacity of the Combined piled raft foundation (CPRF) is improved. Parametric study of response of piled raft foundation has been conducted and the results have been presented. The study is conducted using finite element based software, PLAXIS 2D. The main objective of the paper is to evaluate the parameters that affect the performance of piled raft for an economical and effective design. It has been shown that piled rafts are an economical solution in foundation design compared to raft foundation, for the soil conditions considered in the paper.1. INTRODUCTIONThe aim during the design and construction process of high-rise building foundations in urban areas is to ensure the lifelong safety and serviceability of the new and existing buildings in the neighborhood. In order to realize this aim in a cost-optimized manner, the combined pile raft foundation (CPRF) was developed (Katzenbach et al., 2005). For the foundation of high rise buildings with good subsoil, the simplest structure considered is a raft. But when the subsoil near the ground surface has low load-bearing capacity, high-rise structures are often rested on piled foundations.A piled raft and pile group serves similar purposes, but there are essential differences between them. A pile group is a set of piles that have a pile cap. The piles would be designed to share the pile load at ultimate state. The pile cap would be designed to link the piles together but the contribution of the pile cap to bearing capacity will not be included in the design. On the other hand, a piled raft is a foundation, wherein piles are provided along with the raft so that the total load acting is shared partly by the raft and partly by piles, rather than being dominated by the piles (as in a pile group). Piled raft foundations utilize pile support for control of settlements with piles providing most of the stiffness at serviceability loads, and the raft element providing additional capacity at ultimate loading (Poulos, et al., 2011). Therefore, piles are included in a foundation for two main design purposes: to provide adequate bearing capacity and to bring down the settlements to an acceptable level."

Jan 1, 2015

By Amr Sallam, David Thompson, Moataz Hassan

"The Little Lake Harris (LLH) Bridge was constructed in 1951 to replace the eastwest County Road 48 Bridge connecting the towns of Howey-in-the-Hills and Astatula in Lake County, Florida, United States. The 78-span bridge carries two lanes of traffic, is 3,130 feet long, and 36.1 feet wide. The concrete deck is supported by steel I-girders carried by one row of 18-inch square precast concrete driven pile. In the late 1980's, slight settlements were observed in several bents. In 1990, Florida Department of Transportation (FDOT) initiated annual survey of deck elevations during bridge inspections to monitor settlement. Due to the slow nature and magnitude of settlement, substructure instability was not a major concern to the department. However, public concern over the settlement and rough ride of the bridge continued to rise. FDOT contracted Kisinger Campo & Associates Corp. (KCA) to provide the needed design to correct the dips in the riding surface and minimize future settlement. KCA's initial design was based on the concept of ""helper bents"" at the settled bents in order to restore the bridge to original elevation. Estimated construction cost for seven helper bents was about $3.3M. FDOT requested evaluating other alternatives to reduce the cost of the bridge restoration. KCA involved the geotechnical consultant, Terracon Consultants, Inc. (Terracon), to perform a peer review and provide an economical alternative solution. Jacking and shimming the bridge was determined to be both technically viable and economical with a total cost of less than $300K. The design was completed in March 2010 and construction was completed in February 2011. This paper provides an overview of the LLH Bridge history, summarizes the evolution of the design methodology including the findings of the geotechnical study and presents lessons learned during the design and construction of the project.INTRODUCTIONThe Safety and Preservation of the State Highway System is the top priority of the FDOT. Therefore, FDOT initiated a bridge management program that starts with conducting biennial safety inspections performed by Certified Bridge Inspectors (CBI). The inspection reports together with the CBI’s recommendations are reviewed by a registered Professional Engineer (PE) and work orders are issued with priority ranking depending on the severity of the bridge deficiencies. If the scope of work is considered beyond the in-house crews’ capability, the work is then included in a contract for and bid. LLH Bridge was a little different. It was initiated in direct response to number of complaints the FDOT District 5 Structures Maintenance Office (D5SMO) received regarding settlement of the Little Lake Harris Bridge."

Jan 1, 2015

By Yuji Yamashita, Kazuyoshi Kamimura, Tsuyoshi Takahashi, Naoya Matayoshi

"The CDM-LODIC method (cement deep mixing - low displacement and control) method enables ground displacement to be reduced by removing an amount of soil equivalent to that of injected cement slurry and the volume of the plunged mixing tool, which causes a certain degree of ground displacement. Since the CDM-LODIC method was developed in 1985, it has been applied to over 930 sites and the accumulated volume of stabilized soil has now reached 7.6 million cubic meters.In the CDM method, the number of blade rotations per unit depth in the ground when the mixing blades are withdrawn is considered a construction item. The blade rotation number depends on the degree of mixing between the cement slurry and the ground Some field tests were performed based on the degree of mixing between the cement slurry and the ground. In these tests, a new concept of evaluating the blade rotation number when the screw rod penetrates to a given depth without injecting cement slurry has contributed to the degree of mixing. Furthermore, a correlation exists between the coefficient of efficiency of soil removal and the cement slurry admixture rate. In this paper, we discus the data collected in those field tests and present some application examples.OUTLINE OF CDM-LODIC METHODThe injection of cement slurry may cause some ground displacement during Cement Deep Mixing (CDM). In recent years, due to an increased demand for ground improvement work in urban areas, there is increased concern that buildings near any CDM site may be adversely affected. The deep mixing method which reduces displacement due to mixing (CDM-LODIC method) enables ground displacement to be minimized by removing an amount of soil equivalent to the injected cement slurry and the volume of the mixing tool, which itself causes some ground displacement. When the construction site is near other structures, regardless of whether on or under the ground, the CDM-LODIC method can be used in order to minimize any ground displacement. There are considered to be two main causes of ground displacement as shown in Figure 1. Displacement A indicates ground displacement caused by the volume of the inserted mixing tool during the penetration stage and displacement B indicates ground displacement caused by the volume of the injected stabilizing agent. Thus, by removing soil equivalent to the volume of the inserted mixing tool and the injected stabilizing agent, ground displacement can theoretically be minimized. Figure 2 shows the amount of observed ground displacement in the cases of CDM and CDM-LODIC at an actual site. These case studies indicate that ground displacement can be reduced by removing the soil."

Jan 1, 2015

By Ahmed Elmekati, Frederick C. Rhyner, Steven R. Lowe

"The current phase of the Pacific Park development (formerly, Atlantic Yards) in Brooklyn involves constructing buildings on a platform over an existing LIRR rail yard. To preserve the maximum amount of space in the already congested yard and protect the yard which remains in service during construction, high capacity foundations are being designed well above previous capacities in the area. In addition to spread footings and small mats, various diameters of drilled piles are being used at design capacities ranging up to 600 tons. The piles are generally grouted at low pressure, up to about 50 psi. Load tests for various drilled elements, including piles, tiedowns and soil anchors, have confirmed allowable side resistance (bond) stresses in dense sand ranging from 20 to 30 psi. Testing with different rigs and operators has shown that down-the-hole hammers are feasible, but the installation techniques, types of equipment and size of the pile make a significant difference. The results show that more cost-effective foundations are possible when ample testing confirms expectations.I INTRODUCTIONThe Long Island Rail Road has operated a mainline on Atlantic Avenue since the 1800s, with a terminal at the intersection of Atlantic and Flatbush Avenues. In the early 1900s, the mainline was reconstructed in a cut and cover tunnel section. The LIRR’s Atlantic Yard was constructed circa 1908 to service the terminal. It was depressed about 25 feet below street grade to coincide with the LIRR’s mainline tunnel under Atlantic Avenue. Record drawings indicate that the gravity retaining walls lining the perimeter of the yard and other ancillary structures had been designed for an allowable bearing pressure of five tons per square foot (tsf). Perhaps by coincidence, the mat foundation for the tower of the Williamsburg Savings Bank was also designed for five tsf in 1929.Figure 1 shows a typical geologic section through the site. The geology and subsurface conditions in this part of Brooklyn consist of fill generally five to 20 feet deep underlain by dense to very dense sand and gravel; in places, with numerous cobbles and boulders which make pile installation challenging. The sand strata that are on the order of 150 to 200 feet thick were laid down by glaciers during the last ice age and have been heavily precompressed. The sand strata are underlain in places by remnants of the Cretaceous-era Raritan Clay formation and Fordham Gneiss bedrock. Because of this, the sand strata generally provide excellent support for shallow foundations and the allowable bearing of five tons per square foot is usually easily justified."

Jan 1, 2016

By Glen Mann, H. G. Vestberg, Robert D. Holtz

"Underpinning of residential and commercial structures is often accomplished using a number of driven-in-place small diameter steel pipe piles. These piles, at least in the Seattle area, are typically described as pin-piles and are driven with an air compressor operated jack hammer to a refusal criterion developed from an empirical basis. Over the past twenty years or so, the materials have improved in quality and strength, and the driving equipment has improved in efficiency and capability. These improvements have resulted in damage to the pin-piles during driving as well as to the driving equipment. The primary objectives of this load testing study were to develop a relationship between the driving penetration resistance of 2-inch diameter pin-piles and the ultimate bearing capacity when piles were driven at different penetration rates and, based on the load test results, to develop an opinion regarding an increase in the allowable axial load capacity [ultimate load capacity divided by a factor of safety] of a 2-inch diameter pin-pile over the currently used permissible load capacity of 4 kips in the Seattle area. Also, if feasible, a reduction in the present driving penetration rate was to be recommended to help reduce the rate and magnitude of pile and equipment damage whilst maintaining the allowable load capacity. The recorded ultimate bearing capacities were also compared with the Tagnent-line and the Davisson analytical methods in an effort to determine if either of these provided a reasonable determination of the pile load capacity.IntroductionThis paper describes the results of a series of load tests performed on small diameter, 2-inch, driven-in-place steel pin (pipe) piles and based on these results, provides the support for a modification to the presently used allowable axial pin-pile capacities.The intent of the load testing program was to determine how much influence the penetration resistance might have on the individual piles' ability to support the allowable axial load without undergoing any significant vertical deformation. For the purposes of this paper the ""allowable load capacity"" is considered to be the ultimate pile load capacity divided by a minimum factor of safety, typically considered to be 2.0 in this area. A pin (pipe) pile comprises an open or closed ended, schedule 80 steel tube which is driven-in-place, usually with an air compressor operated 90 pound pneumatic jack hammer. These jack hammers typically operate at a rate of about 1,200 blows per minute, (Haggard, Holtz and Mann, 2001 )."

Jan 1, 2005

By P. Middendorp, Gerald E. H. Verbeek

"INTRODUCTIONStatic Load Testing (SLT) is generally considered the pile testing method that provides the de-facto answers regarding pile capacity and load-deflection behavior. However, as this testing method is time consuming and costly, alternative pile testing methods are applied, such as High-Strain Dynamic Testing (HSDT), commonly referred to as Dynamic Load Testing (DLT), and Rapid Load Testing (RLT), which includes Statnamic Testing (STN) and the Fundex Pile Load Tester (PLT). Extensive descriptions of these pile testing methods as well as comparisons of the results from these two methods have been widely published, but little is written on the choice between HSDT and RLT. This article will address this issue for concrete piles by discussing five different aspects that should be considered when making a choice between HSDT and RLT for either cast-in-situ piles or precast driven piles. TIMINGThe timing of the pile load test is independent of the testing method. For cast-in-situ piles load testing is performed some time after the pile has been installed (to allow the pile to obtain the compressive strength required to withstand the test load), while for precast driven piles load testing is performed after a so-called set-up period following pile installation (to allow the soil to recover from driving induced disturbances and, at least in most cases,regain strength).In other words, the timing of the test does not affect the choice of the testing method.ACCURACY OF THE APPLIED LOADWhen a pile is tested by RLT the applied load is measured by a calibrated load cell placed on the pile head, just as it would be during SLT. This means that the error in the applied load value is less than 0.1% of the maximum range of the load cell.However, when a pile is tested by HSDT the load is calculated from the measured strains, which means that the outcome is dependent on the pile material properties. In this case the applied load (F) on the pile head is calculated by multiplying the measured strain (?) with either the calculated or estimated elastic modulus of concrete (E) and the pile cross section (A).The elastic modulus is generally back calculated from the (average) stress wave velocity (c), which in turn is derived from the reflection time (T) it takes for a stress wave to travel over the pile length (L) from the pile head to the pile toe and back to the pile head."

Jan 1, 2006

By Bora Okumusoglu, Devon K. V. Mothersille

"AnchorTest is an innovative software package, specifically developed for tablets, that permits ground anchor test data assessment and management in real time. The solution has two components: a front-end tablet app runs on the Apple iPad platform, and a back-end Cloudbased system running on Amazon Web Services with an online cross-platform website, which can be accessed from any PC, tablet or even mobile smartphone. This tool provides full data analysis and data management capabilities and portability to create greater efficiency in the anchor testing process. AnchorTest is programmed to accommodate the major international anchor testing codes and incorporates an intuitive user interface, which is revolutionary compared to conventional engineering software designs. The use of this tool creates an environment where the testing of ground anchors has effectively become a paperless exercise with greater efficiency and access to instantaneous feedback on the performance of anchors in relation to established acceptance criteria.Historically, project personnel record and analyze the results from anchor load tests using spreadsheets and a laptop computer and/or on predesigned paperbased test sheets (usually as a backup of the testing). In addition, the processing of the test results is not typically performed in real time as the testing progresses — the calculations and analysis are performed either afterward while still on site (if a field office is available) or after returning to the office. Undoubtedly, on larger projects containing numerous anchors where multiple anchor tests may be performed at the same time, processing, analyzing and accepting the load test data and results can be especially time consuming, which could cause delays to the construction schedule.DevelopmentThe need for a more automated and digitized approach to record, process and analyze the data from anchor load tests was highlighted at a deep basement project for a mixed-use development complex in Moscow, Russia. The diaphragm wall supporting the structure was approximately 1,970 ft (600 m) in perimeter length and about 148 ft (45 m) deep, with an excavated depth of about 82 ft (25 m), which required six levels of single bore multiple anchors (SBMAs). This project provided a challenge to recording, processing and signing off on the data generated from some 3,600 3-unit SBMAs. More specifically, for this project, three hydraulically synchronized stressing jacks were used to stress and proof test each 3-unit SBMA, which resulted in nearly 10,800 data plots of the load-extension tests being generated. This project served as the main impetus in the conceptual design and optimization of AnchorTest."

Jan 1, 2017

By Alexandre Alex) J. Bredikhin

"DISCLAIMER: the statements presented herein are those of the author and do not necessarily represent the views of US DoD or its Components.ABSTRACTProgress on the $750M lock project on the Monongahela River was derailed by discovery of large anomalies in the 6.5-7-ft dia. drilled shafts of the new river wall foundation. The anomalies were located 45 to 50’ below the top of the wall at the critical shaft-to-wall interface, and ranged in thickness from several inches to 2-plus feet. A Specialty team, comprised of representatives from the contractor, the Government, and structural design consultants, was formed to evaluate the extent of the problem and the impact on the new lock wall. With no standard method in place, the Government took the lead to develop acceptance criteria for the repairs while the contractor took the lead to identify the repair means and methods. The Government developed a detailed Quality Control plan to capture and document all of the repair data and to approve each shaft repair in a timely manner. This paper provides an overview of the anomalies encountered and the need for repairs; discusses the details of the repair plan; and provides details on the unique quality control measures employed to verify the repairs. By developing and adhering to a detailed quality control plan, the structural integrity of all of the shafts was successfully restored.INTRODUCTIONThe new Charleroi Locks Project is currently under construction by the U.S. Army Corps of Engineers (USACE) in Pittsburgh, Pennsylvania. In the region, the Corps of Engineers is modernizing the series of locks and dams on the Monongahela River. One facet of this modernization is replacement of the existing Locks #4 (aka Charleroi Locks) located upstream of Pittsburgh, Pennsylvania with new and larger capacity locks. The relative location of the project is shown on Fig. 1. The original construction of twin locks (56’x720’ & 56’x360’) and the fixed-crest dam was completed in 1932, with lock walls supported on timber pile foundations. The fixed crest dam was replaced with a gated dam in the 1960’s. The existing lock is undersized and in poor condition and thus needs to be replaced. The project requires the construction of the new river chamber adjacent to the existing land chamber which must remain operational to navigation throughout the construction. In order to accomplish this, the lock walls need to be constructed in the wet. The river wall was constructed using two construction methods referred to on the project as “cofferbox” and “non-cofferbox” construction."

Jan 1, 2017

By Matthew D. Marks

"The Sacramento Area Flood Control Agency initiated the Natomas Levee Improvement Program in 2006 which would bring the entire 42 mile Natomas Basin perimeter levee system into compliance with applicable Federal and State standards for levee protecting urban areas. The soil-bentonite slurry cutoff has been utilized as the primary construction method for addressing the under seepage deficiencies. To date, a combined total of over 4,500,000 square feet of slurry cutoff wall have been constructed utilizing excavation methods to a maximum depth of 75 feet and deep soil mixing methods to a depth of 90 feet. The construction of these cutoff walls has required the use of newly designed and custom built long boom and stick attachments for large hydraulic excavators and additional resource will be required to complete future phases. Key components of the NLIP program have included advancements in the development of soil-bentonite backfill mix designs, specified ranges on the soil backfill gradation to address concerns of long term consolidation of the backfill material, evaluation of the trench slurry filtrate loss with regard to cutoff wall acceptance, maintenance high slurry densities to provide greater trench stability, and continued development of backfill mixing procedures.IntroductionThe Natomas Levee Improvement Program (NLIP) was initiated by the Sacramento Flood Control Agency (SAFCA) in 2006. The long term objective of the NLIP is to provide 200-year level flood protection to the basin. To date, approximately 21 of the 42 mile Natomas Basin perimeter levee system has been completed, totaling over $100,000,000 in construction contracts, of which slurry cutoff walls make up approximately $25,000,000. Other construction elements include excavation and removal of unsuitable levee materials, raising or widening existing levees, construction of landside seepage berms, drainage canals, and miscellaneous structures.Although each construction phase of the NLIP includes various construction elements of levee restoration program, the slurry cutoff wall is the primary construction element for addressing the under seepage deficiencies. To date, approximately 4,500,000 square feet of slurry cutoff walls have been installed using excavation and deep soil mixing (DSM) methods. This includes approximately 2,000,000 square feet of slurry cutoff wall along 5 miles of the NCC South Levee and 2,500,000 square feet of slurry cutoff wall along 16 miles of the Sacramento River East Levee (SREL). The work has been completed under 8 separate contracts, through SAFCA, and performed between September 2007 and December 2012. A summary of the contract phases and associated cutoff wall square footage is provided in Table 1. Most of the work has been performed within the seasonal dry weather period in the Sacramento valley, which occurs between April and October. This has required much of the work to be performed on an aggressive construction schedule, year after year."

Jan 1, 2017