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By Tim Chapman

This general report considers what promoters of deep basement projects want from their teams and whether they get it often enough. Most large projects are based on complex financial models where the funding is related to a future income stream. Project delays and cost over-runs can critically affect the financial model. Too often, delays and cost over-runs originate in the substructure and foundations. We must take positive steps to improve our industry's reputation for reliability.

Jan 1, 2006

By Malek Smadi, Yazen A. Khasawneh

"New embankments were constructed mostly on soft clays as part of interstate I69 extension in southern Indiana. The embankments serve as bridge abutments and as part of the fill sections along the interstate extension alignment. The height of the embankments range from 50-ft to 125-ft with a maximum foundation thickness of about 75-ft. The foundation soils comprise relatively high compressible fine grained soils. A fully coupled Hydro-Mechanical numerical simulations were conducted for optimizing the construction stages of the embankments. The objective of the staged construction is to allow for sufficient effective stress and undrained shear strength gain to ensure foundation stability under the stage load. Wick drains were utilized to shorten the drainage path and thus accelerate achieving the required undrained shear strength. The extensive field investigation and laboratory testing programs provided a good understanding of the subsurface conditions and allowed the use of a relatively advanced soil constitutive model in the numerical simulations of the staged construction. The effectively designed instrumentation program allowed for monitoring the settlement and pore water dissipation during construction. The pore water pressure, and surface and subsurface settlements from the numerical model predictions reasonably agreed with the instrumentation data over the construction period.INTRODUCTIONThe stability of soft fine grained foundation soils due to embankment construction is dependent on the undrained shear strength of such soils. The permeability, compressibility, and drainage boundaries control the foundation soils response (settlement magnitude and rate) to loading. The settlement magnitude is a function of minerology and soil structure. The settlement rate which is equivalent to the rate of excess pore water pressure dissipation is a function of the soil permeability and drainage boundary. The dissipation rate control the evolution of effective stress and thus the gain of undrained shear strength. As such, if the increase in total applied load is controlled such that enough time is granted for the evolution of the total stresses into effective stresses, then the stability of the foundation soils is enhanced by the gain of the undrained shear strength. The controlled application of the total stress is the definition of the staged construction. From the definition of the staged construction, it is obvious that the process is a coupling of the hydraulic and mechanical responses of the foundation soils."

Jan 1, 2017

By Filippo Mira-Cattò, Andrea M. R. Pettinaroli, Elena Rovetto

"The construction of Powisle station of Metro Warsaw Line 2, in Poland, required the execution of two shafts next to an urban road tunnel adjacent to the Vistula River. The shafts were linked by three conventionally mined tunnels to be excavated 10 m below the water table level, into an upper sandy and sandy silty layer and a lower stiff clayey stratum. After a failed dig attempt under the protection of jet grouting and forepoling, it was decided to deal with the tunnels excavation problem by using the ground freezing technique as a temporary, non-polluting geotechnical treatment, keeping in service the upper road tunnel. The planning of the activities and the executive phases had a significant importance for the success of the work. For work scheduling reasons the mixed system was adopted, i.e. using both the liquid nitrogen system and the brine freezing method. The freezing process management, with a real time evaluation of the soil temperature measured by thermometric strings and an accurate monitoring of the overlying road tunnel structure, allowed the tunnel excavation and lining stages to be performed under difficult conditions, without water leaking from the frozen ground shell, within the expected times and saving extra costs.INTRODUCTIONThe new Underground Line 2 in Warsaw connects the eastern and western part of the town. One of the most critical interferences was the under passing of the Vistula river and of the Wislostrada motorway tunnel, a very congested motorway along the western bank of the river, with the construction of the new station Powisle. The construction of the station required the excavation of two shafts, using the top-down system with the creation of intermediate slabs while deepening the excavation.The shafts were used for the extraction of four Tunnel Boring Machines (TBMs), two approaching from the Vistula river side (east-side) and two approaching from downtown (west-side); in order to connect the two shafts was foreseen the realization of three tunnels, two for the underground lines and the central one for the exchanging passenger platform. These tunnels were underpassing the “Wislostrada Road Tunnel” and interfered with this tunnel foundation, which consisted of diaphragm walls (DW), the “barrettes” (Figure 1).Due to the variable geological conditions at the site, the first excavation stage, with a temporary underground support constructed of horizontal jet grouting columns and forepoling, caused the North tunnel face failure, that required an immediate filling of the empty cavities with lean mix concrete under the Wislostrada tunnel slabs. Thereafter, the recovering attempt with the grout injections could not be completed because of the development of heaves induced on the tunnel structures (Bringiotti et al. 2016). In those conditions the tunnel excavation with traditional technologies appeared to be very problematic, with high risk for the structural safety of the Wislostrada tunnel. This would have meant longer duration for the works and higher costs for the General Contractor as well as for the city Council."

Jan 1, 2015

By Vijaya R, Boominathan A

The design of a rubble mound breakwater resting on a problematic seabed is quite challenging and expensive. In the present study, stage-wise construction of a typical section of the breakwater for a proposed port on the eastern coast of India is carried out. The major challenge envisaged in the design of breakwater is the subsoil strata which consists of soft clayey soil. As it is difficult to improve the soft clayey soil in the marine condition, construction stages are meticulously planned in such a way that consolidation takes place due to the preloading of breakwater, which in turn leads to the strength improvement without any special ground treatment. Thus, the breakwater is designed to be constructed in 7 stages. An initial geostatic analysis is carried out, followed by a plastic stress-strain analysis, consolidation analysis, and safety analysis for each stage, using finite element (FE) code PLAXIS. It is found from the FE analysis that due to the presence of the soft clayey soil, the critical slip circle was formed in the base. It was observed that the staged construction over a period of 2 years provides a sufficient increase in the factor of safety of above 1.5 at the various stages of construction. Hence, it was recommended to construct the breakwater with 7 stages over a period of 2 years.

Sep 1, 2022

By Janaka J. Kumara, Takashi Kurashina, Yoshiaki Kikuchi, Takahiro Yajima

"The inner frictional resistance of open-ended piles depend heavily on the degree of soil plugging. Many factors including pile diameter, relative density and end conditions of the piles influence the degree of soil plugging. In this paper, the effects of inner sleeves attached at the pile base on the inner frictional resistance are discussed. The experiments were conducted on a medium-dense sandy ground using smallscale model piles. The results suggest that the inner frictional resistance is influenced by sleeve height for 50 mm diameter piles although it is independent for 30 mm diameter piles. The results also indicate that soil plug height is influenced by the sleeve height. The results of the incremental filling ratio (IFR) showed that penetration of non-sleeved piles is closer to unplugged state than the sleeved piles. The results of the IFR also reveal that the degree of soil plugging is affected by the sleeve height for 50 mm diameter piles although the variation is very limited in 30 mm diameter piles. The results on the coefficient of lateral earth pressure suggested that it increases from 1.08 – 1.75 when the sleeve height is increased from 10 – 100 mm for 50 mm diameter piles.INTRODUCTIONPrevious studies have shown that the behaviour of open-ended piles is different from closed-ended piles (Szechy, 1961; Randolph et al., 1979; Paikowsky and Whitman, 1990). Open-ended driven piles are widely used for deep foundations, in particular in offshore deep foundations. Generally, it is accepted that a short open-ended pile produces a smaller bearing capacity than a similar closed-ended pile (Nauroy and Tirant, 1983). However, a long open-ended pile can produce a similar bearing capacity as a closed-ended pile due to a large inner frictional resistance mobilised between the inner pile shaft and inner soil (Lehane and Randolph, 2002). The ultimate bearing capacity of an open-ended pile, Qu consists of three components as given in Eq. 1."

Jan 1, 2017

By John S. Civetta, Seth Martin, Marc J. Gallagher, Arthur J. Alzamora, Ronald Peralta

The Crown Building, built circa 1921, is a 26-story iconic building located at West 57th Street and Fifth Avenue in the heart of Manhattan. The paper highlights collaboration between the geotechnical engineer and foundation contractor to develop economical and practical solutions to foundation design and construction challenges associated with this complex redevelopment project. The project includes both below-grade and above-grade expansion of the occupied building, and required undermining the existing foundations, and essentially doubling the foundation loads. The below-grade expansion required surgical foundation work including drilling minicaissons, shoring columns, underpinning, and excavating 20 feet of rock.

By Jakub Szary

Excavation and shoring adjacent to the above-grade Gilmore train station and elevated guideway was undertaken in 2019. A perimeter secant pile cut-off wall was constructed to a depth 37 m (121 ft) below ground surface consisting of 1.0 m (3.3 ft) diameter drilled piles spaced 750 mm (2.5 ft) on-center, tied back with soil anchors, and reinforced with W610 steel sections every 4th pile. A bracing/jacking system was also constructed to support 3 free-standing guideway caissons within the excavation. An automated instrumentation program was installed to monitor movements of shoring walls and train infrastructure in real time and consisted of a robotic total station, inclinometers, tiltmeters, strain gauges, extensometers, and anchor load cells. Baseline monitoring was able to establish diurnal and seasonal movements within the structure, strongly correlated with temperature. The system actively monitored various shoring elements and train infrastructure in real time and alerted the project team when values exceeded predetermined threshold values. Remote reconfiguration of the automated system allowed for more frequent monitoring during jacking of Pier 29 in March 2022. Monitoring data was in agreeance with on-site manual surveying results and jacking dial gauges, and proved to be a reliable monitoring system for construction applications.

Sep 1, 2022

By Bernard Hertlein, Chia K. Tan

"The move to LRFD methods for structural design by AASHTO, ACI, AISC , ASCE, and the FHWA has been a major change for the American construction industry. The deep foundations industry has arguably been placed most at risk by this situation, because of the need for, and the difficulty of providing, reliable quality assurance.LRFD is attractive for both the owner and the engineer because it promises cost reductions, but the assumption underlying LRFD is often overlooked - that the acceptable margin of safety can be rationally reduced, thus saving costs, provided that all the factors involved are closely controlled. This means that both the quality of the materials and the quality of the construction work must be closely monitored, and held to an acceptable standard.This paper describes the type of comprehensive quality management program that is needed in deep foundation construction projects based on LRFD. Case histories are used to illustrate the importance of both adequate inspection and reliable testing to a comprehensive quality management program.IntroductionOver the last thirty years, the major organizations that set standards and practice policies for the American construction industry, such as the American Association of State Highway and Transportation officials (AASHTO), the American Concrete Institute (ACI) , The American Institute for Steel Construction (AISC), the American Society of Civil Engineers (ASCE), and the Federal Highway Administration (FHWA), have embraced Load and Resistance Factor Design (LRFD) as an alternative to, and in some cases, a complete replacement for, Allowable Stress Design (ASD). AASHTO first published a new set of LRFD-based design guidelines for bridges in 1996, with several revisions in 1997, 1998, and 1999 (AASHTO, 1996). The 1996 AASHTO Bridge Design Code was the first in the United States that required foundations to be designed using LRFD procedures. LRFD has a clear advantage over conventional ASD where variability in material strength, bias in design methodology, and degree of construction quality can be rationally accounted for to achieve an acceptable level of risk."

Jan 1, 2005

By Timothy C. Siegel, Derrick Dasenbrock, Rich Lamb, Paul J. Axtell

"The axial resistance provided by deep foundations may be divided into two components: side resistance and tip resistance. The direction that the side resistance acts depends on the relative movement between the deep foundation and the adjacent soil. That is, when the foundation moves downward relative to the soil, then the side resistance is positive and acts upward. Conversely, when the soil moves downward relative to the foundation the side resistance is negative and acts downward. Research supports that both positive side resistance and negative skin friction develop in essentially all deep foundations. The side resistance distribution is a function of the soil strength and stiffness, the applied top loads, and whether the top load is sustained, transient, or a combination of sustained and transient loads. Consideration of drag load and downdrag has become more convoluted with implementation of geotechnical aspects into the AASHTO LRFD Bridge Design Specifications and its use of load and resistance factors. This paper examines the current AASHTO Specifications and presents an alternative design approach for drag load and downdrag using the LRFD framework. The alternative design approach is illustrated by two examples involving drag load and downdrag.IntroductionThe axial resistance provided by deep foundations may be divided into two components: side resistance and tip resistance. The direction that the side resistance acts depends on the relative movement between the deep foundation and the adjacent soil. That is, when the foundation moves downward relative to the soil, then the side resistance is positive and acts upward. Conversely, when the soil moves downward relative to the foundation the side resistance is negative and acts downward. Research supports that both positive side resistance and negative skin friction develop in essentially all deep foundations. The side resistance distribution is a function of the soil strength and stiffness, the applied top load, and whether the top load is sustained, transient, or a combination of sustained and transient.Consideration of drag load and downdrag has become more convoluted with implementation of geotechnical aspects into the LRFD Bridge Design Specifications and its use of load and resistance factors. This paper examines current LRFD design specifications and presents an alternative design approach for drag load and alternative design approach is applied to several examples where drag load and/or downdrag may control design."

Jan 1, 2015

By Paul A. O’Brien, Gary A. Chapman, Thomas G. Cuniowski

"The new Amcor B9 paper mill in Botany, NSW, Australia, involved the design and construction of a new paper mill founded within the Botany Basin Sediments. There were numerous design and construction challenges to address, including tight settlement tolerances for the paper machine footings (6 mm total and 1/2000 mm differential limits), high variable and cyclic loads, deep (>25 m) bedrock and uncontrolled fill material across the site. The mill structure design incorporated a deep driven precast and CFA piled foundation solution, with a comprehensive swathe of testing to validate pile capacity and expected settlements. The pile design for the mill structure included the installation of approximately 1000 piles, with pile testing comprising dynamic testing and a static load test on precast piles. With consideration of Sydney’s increasing demand for development space in relative close proximity to the city’s CBD, industrial areas in the Botany Bay area are likely to make way for heavy or complex commercial and residential structures. Therefore, a better understanding of the engineering behaviour of sediments underlying these areas would allow for efficient foundation solutions. This paper presents a discussion on effective foundation testing techniques and the effects that the behaviour and characteristics of the Botany Bay sediments impose on deep piled solutions.2 PROJECT DETAILS2.1 New paper millThe project involved the construction of the largest recycled paper machine in Australia. The paper machine is 330 m (1080 ft) long, 22 m (72 ft) high, and capable of producing 1.6 km (1 mile) of paper per minute. Construction commenced in early 2011 and new paper mill officially opened in early 2013. The early works contract was awarded to Baulderstone Construction Pty. Ltd. (Lend Lease Corp. Ltd.), with the D&C contract awarded to a consortium headed by Leighton Contractors Pty. Ltd. (CPB Contractors Pty. Ltd.), which included Golder Associates Pty. Ltd. as the geotechnical designer and reviewer.2.2 Site history and effect on local topographyThe site has been used as a paper mill since 1902, and as such, has layers of uncontrolled fill and buried objects within the upper fill materials associated with historical industrial use. The fill material generally comprised of loose and very loose sands, with isolated pockets of cohesive materials, peats, pulped paper and general construction waste. In addition, during construction, underground storage tanks were identified at depth, indicating the historical extent of filling across the site was extensive. The presence of this generally uncontrolled fill was a factor for determining that the most cost effective foundation solution for the paper mill was piled foundations, to bypass these materials."

Jan 1, 1900

By David Sherwood

The paper has been prepared as the basis for the 2008 John Mitchell Memorial Lecture. It reviews major developments in ground engineering over the last 20 years, not from the point of view of technical processes, but from the drivers that have driven these developments and the needs that they have met. It concludes with a glimpse into the future and suggests to where current trends will probably lead us. By its nature such a review is closely aligned with personal experience and it relies heavily on case histories largely from within the writer?s own experience over that period.

Jan 1, 2008

Jan 1, 1997

By Derrick Dasenbrock

Two DFI committees independently organized two complimentary panel sessions for the recent American Society of Civil Engineers' (ASCE) Geo- Risk 2023 "Advances in Theory and Innovation in Practice" Conference in Arlington, Virginia, July 23-26. The Geo- Institute (GI) specialty conference welcomed more than 200 professionals and students interested in risk from around the world to the Washington, D.C., area for three full days of plenary keynote lectures, papers and no-paper sessions. The GI Risk Assessment and Management Technical Committee organized the event, which is the third in a series planned on a 6-year cycle. The previous two events were in 2011 in Atlanta and 2017 in Denver.

Sep 1, 2023

By Kevin Cunningham

"Litigation resulting from neighboring structures with settlement and/or lateral movement or improper pile design and faulty soils engineering analysis, are a multi-faceted opportunity for law firms. These types of claim scenarios are an attorney’s dream, and can obliterate a Deep Foundation Contractors profit and more importantly, can be avoided with a progressive approach to risk management in design and project management.The following (4) case studies will be examined and dissected to discern certain lessons learned for risk management solutions to avoid these deep foundation related challenges in the future.1) Pipe Flotation – Soil Conditions Not Anticipated in Specifications or Contract2) Easement Encroachment – Easement Dimensions Not Recognized Until Completion of Project3) Subjacent Lateral Support – Neighboring Structure Wooden Pile Unprotected Causing Structure to Settle4) Improper Pile Placement - Construction & Design Caused Retail Store to SettleSpecific Deep Foundation project challenges involving: buoyancy calculations regarding subsurface soil characteristics, design factors taking existing subsurface sewer line easements into account, structural instability as result of excavation causing exposure/heavy rainfall to existing wooden piles supporting adjoining building and improper pile location resulting from faulty pile design will be described with risk management recommendations to avoid these challenges in the future.From the very start of construction on any project deep foundation and excavating work poses numerous engineering and technical challenges for developers, contractors and engineers. Dealing with changing or hidden conditions is one of the most difficult challenges facing any contractor or engineer on a project. Relying on incomplete or inaccurate engineering reports is another common problem. Other challenges include dealing with technical errors or oversights that are deeply embedded in the project specifications or bid process.No matter what is the origin of the problem or how it manifests, deep foundation contractors, design professionals and engineers should be ever-mindful of good risk management practices that can prevent serious disputes that can result in costly litigation."

Jan 1, 2015

By Spencer Ness, Yazen Khasawneh, William Tjaden, Mohammad Nassim

The evaluation of long-term performance of the wind turbine structures is essential in lowering the Levelized Cost of Electricity (LCOE) from wind sources. The required maintenance of the wind turbine foundation during the design-life time of the wind turbine may result in escalated cost, if not properly evaluated during the planning and designing phases. The degradation of the foundation soils’ stiffness due to the accumulation small plastic strains resulting from normal and/or extreme operating cyclic loading may result in escalating the O&M cost. The foundation’s stiffness degradation will result in a shift of the wind turbine system natural frequency, which may result in amplifying the vibrations generated at the hub. The anticipated shift of the wind turbine system natural frequency during the design-life time should be investigated through numerical simulations of the anticipated dynamic loading utilizing soil constitutive models that are capable of capturing the foundation stiffness degradation due to the accumulation of such small plastic strains. This study presents the validation of an element model that will be used to evaluate the performance of existing and/or proposed constitutive model.

Oct 1, 2022

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 Frank Rausche

Introduction and Background Testing -Pile Preparation -Data Processing -Data Interpretation/Case Studies Case Studies - Existing Piles Stories from around the world

Jan 1, 2001

By Dario Libano, Luis Carlos Tenuta, Juliano Penteado

"Subway Line Number 4 is one of the newest additions to the Rio de Janeiro subway network. Built for the 2016 Olympic Games, the 16 km (10 mi) subway line connects the south of the city, with the famous beaches Copacabana and Ipanema, to Barra da Tijuca, west of the city, where the Olympic Village and Park are located. This new line, which is estimated to cost USD 2.2 billion, is composed of six new stations: Jardim Oceanico, São Conrado, Gavea, Antero de Quintal, Jardim de Alah (JA) and Nossa Senhora da Paz Station.Brasfond participated in the construction of foundations and retaining structures for all the stations, and each presented unique challenges. This is not surprising considering the difficulties present in a highly-dense urban environment including utilities, nearby buildings, traffic limitations and noise.Of all the stations, JA Station was the most challenging to construct. It was located in the middle of an avenue between residential high rises supported on shallow foundations as well as below sea level in sands with high groundwater. The other five stations were located in small parks and squares, with no buildings in the immediate proximity.The interaction between designer, owner, and the general and foundation contractors during execution was key in safely reducing the construction schedule. This was significant given the unforeseen construction delays the client, Linha 4 Sul JV, faced due to permitting, utility and traffic relocation so that the owner could fulfill their final goal: making the line operational by the Olympic Games. The GeologyGeologically, the state of Rio de Janeiro is formed by Pre- Cambrian crystalline basement rock. Its geological formation is very old and comprises two major orogenic cycles, a Mid-Precambrian formation, called “Transamazonian” (Proterozoic Era), and an Upper-Precambrian to Cambrian called “Brasiliano” (Proterozoic-Paleozoic). The soil structure of the city of Rio de Janeiro is represented by a core of crystalline rocks, usually granite-gneiss, covered with a layer of residual soil and/or partially weathered rock.JA Station is located in a Rio de Janeiro neighborhood called Ipanema, between the Atlantic Ocean and Lagoon Rodrigo de Freitas. Local geology is composed of a superficial soil, consisting of medium to coarse grained sands. Top of rock varied significantly from 20 m (66 ft) deep on one side of the station to 33 m (108 ft) on the other. Water is at a depth of 3 m (10 ft)."

Jan 1, 2016

By Tracy Brettmann

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

May 1, 2022

By 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