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By Donald A. Deardorff

The capacity of a helical pile can be determined analytically using the individual bearing or cylindrical shear methods which are dependent on soil strength parameters and helical bearing area. The torque correlation method is widely used in the helical industry to determine the capacity during installation by monitoring torque during the final seating of the helicals. This method has been shown to be a better predictor of strength than the individual bearing or cylindrical shear methods. To determine capacity using the torque correlation method, the final average installation torque (ft-lbs) is multiplied by an empirical torque correlation factor (Kt, ft-1). Kt values have been well documented for square bar shaft helical products and can vary from about 3 to 20 ft-1 depending on pile geometry and soil type. A default value of 10 ft-1 is generally used for all square shaft sizes and soil conditions. Less research has been done on determination of Kt for round pipe shaft helical products. Studies have indicated that factors which affect Kt include soil type/strength, number of helical plates, helix spacing, helix pitch, depth of embedment, downward pressure (crowd), shaft diameter (round pipe) and load application direction while other studies have discounted some of these factors as inconsequential. This paper reviews past research findings regarding Kt determination for square and round pipe shaft helical products and presents a case history of round shaft helical pile installations in Chicago clay which resulted in much lower than expected Kt values.

Jan 1, 2007

By Ping Yang, Tian-bin Li, Min-hui Wu

"The process of filtrate loss of low solid-phase drilling fluid at different content of polyanionic cellulose is investigated by the standard filtration test. The test results showed that when time of filtration is same, the filtrate volume decreases linearly with the increase of content of polyanionic cellulose. When content of polyanionic cellulose is same, the velocity of filter loss decreases nonlinearly with the increase of time and the velocity of filter loss will reach a stable value. The filtrate volume in 7 to 8 minutes can reach half of the total filtrate volume. At the same time, the velocity of filter loss of drilling fluid decreases nonlinearly with the increase of viscosity. When apparent viscosity is between 3.5~4.15 mPa.s, decrease speed of velocity of filter loss is quick. The results are helpful for characteristics evaluation of filtrate loss of drilling fluid and control of filtrate loss.IntroductionDuring the process of drilling, water of drilling fluid can leakage into stratum, the water can result in instability and collapse of borehole wall. At the same time, the original ratio of drilling fluid will change. The density of drilling fluid will increase, the performance of the drilling fluid will change. Controlling amount of filtration is important to drill successfully. The additives of controlling filtrate loss are mainly two types, particle materials and polymer materials. High-molecular polymer is a kind of high-molecular material, has the adsorption effect, high polymer protection, can improve the advantages of slurry viscosity (Xu,2004 and Dehghanpour,2001). Some scholars carried out some study on the polymer material fluid loss agent in recent years, these study mainly focused on CMC, HEC, MHEC, CMHEC, starch and its derivatives(Zhang,2005 and Chevron,2009).About PAC (polyanionic cellulose) as drilling mud additives, a few of scholars carried out some relevant work. Plank (1992) applied PAC into ordinary freshwater drilling fluid and analyzed temperature stability of freshwater drilling fluid. Bennion (2000) applied PAC into drilling fluid and analyzed effect of polyanionic cellulose on strata inhibitory. Huang (2011) analyzed effect of PAC on properties of the high-density water-based drilling fluid. Mahto (2004) applied PAC into fresh water and salt-water drilling fluid and analyzed effect of PAC on rheological properties of the drilling fluid. Wang (2008) applied PAC into alkaline drilling fluid to study various performance of drilling fluid. PAC is a renewable resource and has good application prospect (Ankara, 2005). So it is very important to understand the effect of PAC on filtration process of drilling fluid.The test was conducted by changing the content of the PAC in drilling fluid. The object of this paper is to understand effect of polyanionic cellulose on filtration process of the low solid-phase drilling fluid."

Jan 1, 2017

By S. Ahmed

Critical factors of selection, fabrication, installation, and splicing of prestressed concrete piles are discussed based on experiences with coastal subsurface conditions of the United States of America (USA), and the People's Republic of China (PRC). Segmented Prestressed Concrete piles are economical when compared with other pile types of comparable capacity. However, strict quality control measures are required.

Jan 1, 2010

By Bernard H. Hertlein

The introduction of LRFD methods for structural design has been a gradual process by AASHTO, ACI, AISC, ASCE, and the FHWA, which has largely been ignored by the deep foundations industry. In 2007, however, the industry has been obliged to embrace LRFD for any deep foundations on projects involving federal funds. The authors are concerned that the risks caused by the need for, and the difficulty of providing, reliable quality assurance, will result in unnecessarily high safety factors that will defeat part of the purpose of LRFD. A primary attraction of LRFD for owners and engineers alike is that it promises more efficient design, and therefore cost reductions. Unfortunately, a key element of LRFD philosophy is often overlooked - that the applied safety factors can be rationally reduced, often allowing less material to be used, thus saving costs, but only if all the risk factors involved are identified and closely controlled. This means that both the quality of the materials and the quality of the construction work must be adequately monitored, and held to an acceptable standard. In the case of deep foundations, the soil in which the foundation is constructed is also a critical component that must be taken into account in the assessment of risk factors.

Jan 1, 2007

By Daniel Ruffing, Jeffrey Evans

Vertical cutoff, or barrier, walls are an integral part of environmental site remediation efforts. Vertical barriers are commonly deployed to limit the influx of clean ground water and/or to control the off-site migration of contaminated groundwater. The level of detailed design consideration devoted to the vertical cutoff wall component varies widely from project to project and generally decreases with decreasing size and complexity. For those projects receiving minimal design effort, conservative design decisions can lead to unnecessary costs or unanticipated conflicts between the various design considerations. In this paper, the authors discuss several important design and construction aspects of vertical cutoff walls requiring particularly careful consideration during the design phase of the project. These design and construction considerations include the need for and extent of excavation for a key, project target hydraulic conductivity, the use of statistical allowances in the specifications, filter press testing, sand content of in-trench slurry, cleaning of the backfill slope, measurement of stress and strain, the additional of slag in cement-bentonite cutoff walls, and longevity of cutoff walls.

By Paul Doherty

The offshore wind sector is booming on a global scale, with the U.S. becoming a front runner in this highly progressive market. The Global Wind Energy Council has highlighted the exponential growth in both fixed bottom and floating projects in the years ahead, with global installed capacity set to exceed 300 GW by 2030. This growth in installed capacity is primarily related to fixed bottom projects, which have dominated the market for the past 20 years. However by the tail end of this decade, floating projects are likely to become

Oct 1, 2022

By John P. Briand III, Douglas J. Aghjayan, Robert E. Fosse

This paper highlights the successful pile load testing program for the redevelopment of Pier One in East Boston, Massachusetts. Pier One is a 5.4-acre parcel on a dormant waterfront site used in the 1950s as a warehouse and distribution facility. The developer plans to re-use the existing 14-inch-diameter concrete-filled steel pipe piles to support four 5- to 7-story apartment buildings above a 2-story parking garage. A pile load testing program was developed to establish if the existing piles could support design loads of 240 kips for project financial feasibility and up to 300 kips for a significant reduction in future foundation costs. The Phase 1 program consisted of statnamic and dynamic load testing on two piles with two loading intervals (200 and 240 kips). Based upon the favorable results of the Phase 1 program, the Phase 2 program involved statnamic load testing on two piles and dynamic load testing on ten piles with three loading intervals (200, 240, and 300 kips). The Phase 2 program confirmed the favorable results which were applied across varying strata thicknesses and pile embedment depths. The average allowable capacity for the piles tested was greater than 300 kips with pile movement up to 0.3 inches.

By Michael J. Weaver

Urban redevelopment projects are occurring more frequently than ever before as urban greenfield sites become limited and city planners and devel- opers attempt to revitalize existing underdeveloped neighborhoods. How- ever, because of the past usage of many urban sites (some dating back 100 years or more), designers and construction teams have to not only engineer founda- tions to accommodate the subsurface soil and ground water conditions, but also to work around the relic founda- tions or structures that have been left behind from previous developments. In these cases, a one-size-fits-all approach to foundations may not yield the most cost- and schedule-effective approach, and hybrid foundation systems have to be evaluated.

Apr 1, 2022

By Peter A. Thompson, Richard E. Prust

"The Bangkok Mass Rapid Transit (MRT} Chaleom Ratchamongkhon Line project is the first underground subway to be completed in Thailand. It consists of 22 km (14 miles) of twin-bored tunnels and 18 cut and cover stations constructed within the deltaic deposits that underlie the city. This paper describes the ground conditions, site investigation, including the use of the self-boring pressuremeter and the associated design issues for the construction of deep foundations. The paper also describes a selection of the various deep foundation solutions that were adopted to address particular constraints of the project and the ground conditions, including slurry walls for the cut and cover stations and foundations used for the underpinning of existing structures.INTRODUCTIONThe MRT Chaloem Ratchamongkhon Line Mass Transit Underground Railway comprises approximately 22 km (14 miles) of tunnels and 18 stations. The route is shown in Figure 1.The project was divided into two design and build contracts. The northern section was awarded to the ION joint venture, composed of Italian-Thai Development PLC, Obayashi Corporation and Nishimatsu Construction Co Ltd. Arup were contracted by ION for the design of the northern section. The section comprises 11 km (7 miles) of twin-bored tunnels, nine cut and cover station tunnels constructed within perimeter slurry walls using top down construction methods, and two cut and cover tunnel structures.The majority of the route of the northern contract follows existing highway Rights of Way. This results in the tunnel alignment passing through the foundations of existing highway bridge structures for which a variety of deep foundation solutions were adopted to underpin these structures.An 8-story park and ride building in the Lat Phrao area was also constructed using deep foundations."

Jan 1, 2005

By H. Mori

This paper describes a new borehole loading test using a self-boring instrument appropriate for dense sandy soils and stiff clayey soils. The results of loading tests for the bearing strata of deep foundations according to this method are also presented. This method has been applied to the study on the settlement behavior of heavy foundations resting on dense sand, stiff clay or soft rock in Japan.

Jan 1, 2010

By Andrew Middleton, Mark Wyatt

"The Brickworks Marketplace Project is a significant shopping centre development in inner north west Adelaide constructed by Badge Constructions in 2014 and 2015. The site was a former brickworks with a deep pit containing various extents of uncontrolled fill which was to remain on site, and with a remaining void up to 6 m in depth. The existing uncontrolled fill was improved using the High Energy Impact Compaction system, and the pit backfilled using a quarry crusher byproduct selected by trial and a recycled crushed concrete and bricks and compacted in deep lifts. This approach resulted in significant savings in compaction time, cost and building foundations. The settlements of various parts of the completed works have been monitored since February 2015 and this monitoring has demonstrated small settlements which meet the user’s constraints.INTRODUCTIONThe Torrensville Brickwork Markets project involved the transformation of a former brickworks and clay pit site into a regional 17,000m2 shopping centre, opening in June 2015.The site was a former brickworks with adjoining clay borrow pit. The clay pit had been partially backfilled over many years with ‘uncontrolled’ fill comprising ‘clean’ soil, bricks and kiln dust typically of the following thicknesses:??of the order of up to 7 m to 10 m but locally up to 15 m in the western part of the site??2 m to 5 m in the south-eastern part of the site; and??less than 0.5 m in the north-eastern part of the siteAnecdotal reports suggested compaction of some of the fill may have been undertaken, although this not able to be confirmed nor records obtained.Initially it was proposed to take up the existing uncontrolled fill, sort and recompact or remove to landfill, followed by backfilling in conventional means over 500,000 cubic metres of imported filling to a thickness of up to approximately 6m to backfill the former pit. This work represented a significant cost and was not economically viable.During early negotiations, the contractor proposed an alternative to retain and ground improve the existing filling on site, and to backfill the pit with fill placed and compacted in deep lifts, thereby significantly improving the economics, environmental and community impacts of the proposed works.The developer agreed to the proposal with the following performance criteria:??a settlement of =10 mm after 10 passes by the Impact Compactor (on existing subgrade areas);??a bearing capacity of 250 kPa for high level footings;??a maximum long term differential settlement of 40 mm (measured over 16 m), ie. 1 in 400; and??a minimum modulus of 40MPa."

Jan 1, 1900

By Peter Faust, Peter Hubbard, Kenichi Soga

The European Federation of Foundation Contractors (EFFC) and The Deep Foundations Institute (DFI) have set up a task group to compile a Guide for Working Platforms. The first edition of this Guide has been published in January 2020. The aim of the Guide is to provide reliable methods for design, testing and verification of working platforms for construction equipment, especially in the deep foundation industry where track loads can be excessive due to the nature of its operations. The Guide has identified areas where knowledge is limited. Actual track pressure and its distribution along the length of the tracks is still not well researched. Current recommendation provided in EN 16228-1 are believed to be overly simplified and may lead to conservative requirements for working platform thickness. This paper presents results of a series of field tests where the actual track pressure of a large drilling rig during operation was measured in real time together with the deformation of the working platform. Embedded, distributed fiber optic sensing (DFOS) at different depths throughout the platform allowed for a three-dimensional evaluation of the platform deformation throughout the entire operation. Results will help to develop more reliable recommendations for future safety requirements of working platforms for deep foundation equipment.

May 1, 2022

By Kenneth E. Henn, David B. Paul, John D. Rice, Brian H. Greene

"Several laboratory modeling programs have been conducted to investigate the mechanisms associated with internal erosion of dam embankments and foundations. The investigation consists of developing laboratory devices to model three separate mechanisms associated with process: 1) contact erosion along bedrock joints, and 2) piping into an open bedrock defect. The contact erosion device subjects the soil above a bedrock joint to high velocity flows in the joint. The erosion into a bedrock defect device examines a number of static and transient hydraulic conditions to study the mechanisms associated with this type of erosion. Numerous tests have been conducted using both devices. The results of the modeling will be discussed along with a discussion of how this information could be used in future dam design and risk assessment studies.IntroductionA series of laboratory modeling programs were performed to assess the seepage and internal erosion behavior of several man-made and natural structures within dams and their foundations. Each model was performed on a “bench scale” and depicted an isolated location where internal erosion was likely to occur. The models were subjected to hydraulic boundary conditions to simulate the in-situ conditions so that the processes of internal erosion could be observed. Two laboratory devices were developed to model conditions depicting 1) contact erosion along a bedrock joint in contact with a dam embankment, and 2) backward erosion (piping) into an open bedrock defect (joint, solution void, etc.).Embankment dams often have rock foundations containing defects which may detrimentally impact future performance. Further, there are existing foundations which contain rock defects that may already be detrimentally impacting the dams; however, due to the inherent aspects of the mechanism, the signs of distress may not have propagated to the surface and thus not observed during inspections. A better understanding of the mechanisms which are influenced by, and impose their influence upon, rock defects will enhance the ability of dam safety professionals to analyze the risks associated with internal erosion due to rock defects, increase our ability to monitor and successfully initiate earlier detection, and also increase our ability to design remediation methods to contend with rock defect failure modes."

Jan 1, 2016

By Richard Hanke, Franz-Werner Gerressen

"The twin decked Alaskan Way Viaduct is a passage to Seattle’s downtown waterfront and of great economic importance to the city. In 2001, the Nisqually earthquake damaged the viaduct and led to the redevelopment of this corridor. The project includes two miles of 57.5 ft diameter bored tunnel beneath downtown Seattle and a stretch of new highway and overpass bridges at the southern tunnel entrance. State-of-the-Art special foundation equipment was mobilized for the project to perform a broad range of geotechnical construction. Applications included soil mixing and jet grouting for confinement cells around new bridge foundations, large diameter secant pile walls for the Tunnel Boring Machine launch portal along with an extensive jet grouting regime for ground improvements within the tunnel alignment. This paper will study the evolution and use of advanced special geotechnical construction equipment and describe its application at the Alaskan Way Viaduct Replacement Project.INTRODUCTIONThe evolution of geotechnical construction equipment continues through innovative applications and continued modification or enhancement of machinery. Similarly and in parallel, market expectations continually demand more in terms of construction speed and performance. Together, market demands and contractor innovation have led way to the development of specialty geotechnical construction equipment with capabilities previously not seen feasible or possible. Several examples of this scenario have recently developed during design and construction of the Alaskan Way Viaduct Replacement Project.The Alaskan Way Viaduct Replacement Project is a joint project between the Federal Highway Administration (FHWA), the Washington State Department of Transportation (WSDOT), and the City of Seattle. Three build alternatives were under consideration for replacing the Alaskan Way Viaduct: the Bored Tunnel Alternative, the Cut-and-Cover Tunnel Alternative, and the Elevated Structure Alternative. Ultimately, the bored tunnel option was selected as the best value approach. The project includes two miles of 57.5 ft diameter bored tunnel beneath downtown Seattle and a stretch of new highway and overpass bridges at the southern tunnel entrance. Several other associated improvements tie into this project that will ultimately lead to the complete demolition of the viaduct and redevelopment of Seattle’s waterfront."

Jan 1, 2015

By Kozo Takeda, Arashi Shimano

"Dry Jet Mixing (DJM) technique is widely known as soil mitigation technique with small ground displacement during installation comparing with other techniques. Some projects involving sensitive structures, however, require smaller impact than in conventional technique. In order to reduce ground displacement during DJM installation, this paper introduces systematic mixing technique, RD-DJM (Reducing Displacement – Dry Jet Mixing). RD-DJM is characterized by injection nozzle on the rim of mixing blade and fin plate on mixing shaft. These devices contribute efficient collection of injected air toward mixing shaft and result in reduction of ground displacement. The authors demonstrate successful performance of RD-DJM indicating difference between conventional installation and RD-DJM technique.INTRODUCTIONThe Dry Jet Mixing (DJM) method is one of the most common techniques in Japanese deep soil mixing field and characterized mechanical mixing of powdery binder with in-situ ground (dry-mixing technique). It is widely believed that DJM Method has great advantages in less quantity of binder to achieve the desired strength and less waste generation during installation.DJM method can meet the required strength with less binder content than wet mixing. And volume of binder of dry mixing is absolutely less than wet-mixing injecting considerable volume of binder slurry. This means that dry mixing causes less ground displacement compared with wet mixing.As the medium for forced feeding of the binder, the DJM method uses compressed air, which is blown from the mixing blade nozzles to scatter the binder and then recovered through the periphery of the mixing shaft to the ground surface. Because the binder is injected outward from the injection orifice at the root of the mixing shaft, a part of the air may escape to untreated areas due to the blockage of air recovery path around the mixing shaft. Figure 1 illustrates possible escaped air and leakage around installation location."

Jan 1, 2015

By Matthew Janes

The installation of piles and casings is becoming increasingly difficult as restrictions on vibration become common in major urban areas. The use of high frequency, resonant excitation of a pile or casing permits ease of installation of sections to great depths with near imperceptible vibrations as close as 1 pile diameter. The new Resonant Driver is able to excite a pile at its resonant frequency (up to 150 Hz or 9000 VPM) to produce elevated levels of acceleration, force and displacement in the pile. The combination of extremely high acceleration and controlled levels of displacement allow the pile to slice through varied soil with almost no vibration translated into the ground. In direct comparisons between conventional vibrators and impact hammers the Resonant Driver produces less than 1/50th the vibration. The Resonant Driver results in ground vibration of between 1/20 and 1/40 of common limit levels (1 cm/s or 0.5 in/sec) as close as 1 pile diameter. At a distance of 5 m (16 ft) from the pile or casing vibration levels approach imperceptible levels. The Resonant Driver uses a proprietary algorithm to tune the drive vibration to the changing natural frequency of the pile as it is driven into the ground. By maintaining resonance the energy in the pile is built up like in a flywheel on an engine or a child on a swing. This build up of energy aids in driving and significantly reduces waste. Recent experience using the Resonant Driver is proving the technology can drive a variety of steel pile and casing sections through varied soils. Continued use of the Resonant Driver will create a data base of various pile and casing sections, soil types and achieved capacities.

Jan 1, 2008

By Frank Albrecht, Brian McCarthy

"The Ararat Terminal Station (ARTS) is located 190km to the north-west of Melbourne, approximately 1.7km to the north of Elmhurst Township in the Pyrenees region of western Victoria, Australia. The site occupies an area of approximately 7.2 hectare of farmland. The electricity generated by the Ararat Wind Farm is directed to the ARTS terminal station before being connected to the grid. The ARTS structural design includes more than 180 steel yard support structures, three 25m-tall gantry ‘A’ frames, three modular control room buildings, a precast transformer bund, precast fire wall structures and related foundation design. Innovative driven engineered glue laminated timber (glulam) piles in a cruciform shape were used to reduce the foundation construction time, cost and the amount of concrete used in the project. It is the first time that engineered timber piles made from farmed Australian pine trees have been used in a large-scale environmentally-friendly project. Durability of the timber was achieved by H5 treatment and the use of reinforced concrete pile caps to protect the cruciform timber piles at the ground line. A pile-driving sequence was developed based on field trials. The lateral load capacities of the piles were estimated using engineering principles and from full-scale tests in the field. This paper provides an overview of details of engineered timber cruciform piles, durability of timber piles, design information, pile construction procedures, pile-driving procedures, the testing protocol, test results and validation. The test results were compared with predictions from several methods. In addition, potential future applications of similar systems in other infrastructure projects, and opportunities for future improvements are discussed. The structural aspects of this project were presented in a previous paper at the World Conference on Timber Engineering in Vienna in August 2016. See http://wcte2016.conf.tuwien.ac.at/home/ for further information."

Jan 1, 1900

By X. Y. Hou

The design practice of several circular underground projects with large diameter is summarized. By taking the advantages of load-bearing of circular structure, a rational annular tensile bar support system and a new design method are proposed. Calculation for a car park shows that remarkable results are brought in by this design technique.

Jan 1, 2010

By Bryan Bet

Retaining wall systems of soldier pile ground anchors (SPGAs) have been used for many decades to stabilize landslide activity. Due to successful use of these walls to address slope instability on the California state highway system, their use has expanded to include larger, more complex landslide mitigations. The increase in size and scope of SPGA wall applications, combined with more stringent seismic design standards, have created new and unique challenges for design and construction. Constructability issues are revealing themselves in real time in Northern California, where the California Department of Transportation (Caltrans) recently completed two large SPGA wall projects on state highways: the Peregrine Slide Project in inland Mendocino County, and the Westport Slide Complex located along coastal Highway 1. Each presented unique construction challenges that needed to be overcome quickly to make the projects successful. This article highlights some construction difficulties encountered on these projects, in greater depth, than what I covered last summer at DFI's S3: Slopes, Slides and Stabiliza- tion conference in San Francisco. Also covered are what steps were taken to overcome these difficulties, and mitigation advice for future wall designs. Specifically, ground anchor installation interference, ground anchor elongation variance, and difficulties with large diameter ground anchor drilled holes will be discussed.

Jul 1, 2022

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