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By Bartho J. Admiraal, Antoine Feddema

Pneumatic sinking of caissons has been established from mid-19th century. The technique of pneumatic sinking has been applied on many projects for underground construction up to depths over 20m below groundwater level since that time. Volker Staal en Funderingen, a known deep foundation contractor in the Netherlands, was awarded two contracts in 2015 for sinking in total 2 caissons in Hamburg (Germany) to large depths (over 30 m (100 ft) and two projects near Amsterdam (the Netherlands). The latter concerned two gate chambers for the world’s largest sea-lock, one of them was 55x81 m2 (180x266 ft) to a depth of 25.5 m (84 ft), which would mean a world record for pneumatic sinking! But with depths and dimensions like these, the deployment of personnel is the main limiting factor for production, despite all developments to date. It was decided to develop a remote controlled process, including the necessary equipment and monitoring systems. Monitoring not only the kinematics of the equipment in the working chamber and the production parameters related to the excavation but also of the structural behaviour of the sea-lock gate chambers was essential for approval of this innovative execution method. The lay-out and the sizes of the largest caisson the structural integrity was extremely critical for torsion and bending moments. A displacement controlled execution by the observational method was therefore required. In engineering a new approach for modelling the semi-continuous failure mechanisms of the soil was needed to understand the sensitivity of the excavation process and to define limit values for the execution. In the paper these structural and geotechnical issues will be explained together with the experiences during the execution.

May 1, 2022

By Bo Westerberg, Mattias Andersson, Yvonne Rogbeck

"Deep stabilisation has been used in Sweden for decades. The method has been improved to allow it to be used in different types of soils and with new binders. One challenging soil type in Sweden is so-called sulphide soil, a fine-grained soil which contains organic material and iron sulphides. There have been some cases in Sweden of problems when using deep stabilisation in this type of soil, and in one case a slope failure occurred. This paper shows that it is possible to achieve good results with deep stabilisation in sulphide soils. Laboratory and field studies from a test site along the Botniabanan railway line in Sweden are presented. Geotechnical and chemical properties of the natural soil were investigated in the laboratory and one or more of these properties may explain the differences in the stabilising effect of sulphide soils. The strength of the laboratory samples and the columns in the field were tested and compared. It is shown that a satisfactory stabilisation effect can be achieved with the proper choice of binder, amount of binder added, curing time and mixing energy. In sulphide soils, more binder additive is needed than in “ordinary” inorganic clays.1. INTRODUCTIONThe term sulphide soils is used in this paper to refer to the unique types of sulphide soil commonly found in the coastal areas along the north-eastern coastline of Sweden between the cities of Gävle and Haparanda, a distance of about 900 km. Sulphide soils are in general very compressible, susceptible to creep deformation and normally show low undrained shear strength. A sulphide soil may have a negative environmental impact through acidification and chemical action if it is subjected to oxygen, for example during excavation or lowering of the ground water table, Mácsik (1999). In foundation engineering works, efforts are made, for environmental or/and economic reasons, to use the sulphide soil as the foundation instead of excavating it. Deep stabilisation by means of columns is a potential method for use when sulphide soil needs to be improved in order to reduce settlements or/and increase the stability of embankments.Sulphide soils were formed as sediments at river mouths and off the coast in the special environment prevailing at the time of sedimentation, Mácsik (1994). The water in which the sulphide soil was sedimented was brackish/sweet and the environment was typically deficient in oxygen. The environment prevented complete decomposition of the organic material in the sediments. As a result, sulphide soils were formed primarily in the form of a fine-grained composition of clay and silt minerals, iron sulphides and organic matter. Such environments still exist today and new sulphide soil sediments continue to be formed."

Jan 1, 2015

By Cheng Lin, Guoming Lin

"This paper presents a case history for the design, construction and long-term performance monitoring of a driven prestressed concrete (PSC) piled foundation supporting a large liquefied natural gas (LNG) tank in Savannah, Georgia, USA. Following a geotechnical investigation, a design stage pile test program was performed with three objectives: to study the densification effect from pile driving on the liquefaction resistance, to test axial and lateral pile capacities, and pile behavior under lateral loads. The test program comprised five piles driven on a test pad constructed adjacent to the tank foundation. Cone penetration testing (CPT) was performed before and after pile installation to test soil densification effects from the pile driving and liquefaction potential was re-evaluated based on the soil densities after pile installation. The axial load tests involved static load testing, high strain dynamic testing, and Statnamic testing. This paper presents the findings of the densification effects, compares results from different axial testing methods and discusses the procedures to use the load test results in the pile design. The paper also comments on the construction issues and presents performance data with 10 years of monitoring.1. IntroductionThe project site is located at the Kinder Morgan’s Elba Island LNG Terminal on the Savannah River which is three miles downstream of the downtown Savannah, Georgia. This LNG terminal was initially developed in the 1970s as an LNG import terminal. The facility includes five LNG storage tanks with two larger tanks which were constructed in 2003 and 2006, respectively. The terminal is currently being converted into a liquefaction and export facility. This paper discusses pile foundations for Tank D4 which is a double walled insulated steel tank built to hold one million barrels of LNG in 2003. This tank has an outer tank diameter of 258 feet, an inner diameter of 252 feet, and liquid height of 113 feet. A number of geotechnical challenges were present in the foundation design and construction.??The site is a typical coastal deposit site featuring a thick layer of very soft under-consolidated clay (up to 40 feet in thickness);??The bedrock is a couple of thousand feet deep;??There is a sand layer that is liquefiable under a high seismic design category (0.5% possibility of exceedance in 50 years)."

Jan 1, 1900

By Jason Herron, Joseph Brown

The common couplings for joining sections of helical piles with an outside diameter of 6.625 inches and 8.625 inches are square on square, flange to flange, external pipe sleeve, internal pipe sleeve, and welded joint. Each coupling type has advantages and disadvantages in efficiency, capacity, installation, and economics of the installed pile. All these coupling types have been used in the helical pile market in North America for various applications and designs. Many of these applications require on-site testing, but test records are not typically shared with the helical pile industry. Due to the lack of information available for square on square and flange to flange couplings, testing was done to compare the efficiency of installation, load to deflection response, and torque to capacity ratios of external pipe sleeve, square on square, and flange to flange couplings. Field installations and tension tests were performed in non-cohesive (sand type) soil near Caseyville, IL and in cohesive (clay type) soil in Centralia, MO. The data collected during these tests included rotations per foot during installation, installation torque, applied pressure, and deflection. The results of this testing are analyzed and discussed within this paper. The results indicate that the square to square coupling is the most efficient of the designs tested, but this conclusion cannot be fully justified without further testing due to the variability in the data gathered and the small number of piles tested. INTRODUCTION A helical pile is typically assumed to be a medium-displacement pile when its outside diameter is between 4.5 inches and 8 inches and a high-displacement pile when its outside diameter is greater than 8 inches. A helical pile designer has multiple options when selecting a coupling type for medium- to high-displacement helical piles. Each type of coupling has advantages and disadvantages and must be analyzed on the bases of efficiency, capacity, installation, and economics of a project. Typical couplings that are chosen by designers include square on square, flange to flange, external pipe sleeve, internal pipe sleeve, and welded joint. A helical pile must transfer axial, lateral, bending moment, and torsional loads, and the coupling must be designed to effectively and efficiently transfer each type of load. During the installation of a helical pile, the rate of penetration and the disturbance of soil layers play a critical role in the efficiency and torque to capacity ratio (Kt) of the pile. It is common for a coupling to protrude beyond the outside diameter of the pipe section being used. This is necessary for the function of certain coupling types and can facilitate the connection of couplings. However, it causes increased soil disturbance and reduce the rate of penetration due to soil bearing against the protruding portion of the coupling. A helical pile designer typically will work to minimize the coupling protrusion and create a pile with optimal installation efficiency but may choose a design with lower installation efficiency if it offers sufficient economic advantage.

Jan 1, 2019

By Kozo Takeda, Arashi Shimano

"Dry Jet Mixing (DJM) method as the representative deep mixing technique has been demonstrating best practice on ground mitigation works coping with complicated soil condition and limited site space. This technique plays an important role in many projects to stabilize soft ground involving troubles like sliding failure, settlement, bearing capacity etc. Serious disasters caused larger earthquakes make great demand on the application of deep soil mixing these days. Special design and alignment of deep soil mixing has been established against to liquefaction and serious failure due to liquefaction. In this paper, representative example of liquefaction mitigation by DJM method is summarized. The paper also present result of surveillance of sites installed DJM col umns after attack by Tohoku Pacific Ocean Earthquake. Performance of DJM columns suffered the earthquake is demonstrated at several sites even with conventional column alignment.INTRODUCTIONThe DJM method is a representative deep soil mixing technique of dry mixing manner in Japan. DJM can successfully install soil mixing columns trough automatically controlled binder injection based on pneumatic feeding theory and cumulative experiences.This method was joint-developed in 1978 by private organization under initiative of the Public Works Research Institute of the Ministry of Construction as the optimum method for improving the Japanese soft ground. Figure 1 shows full view of the DJM construction system. Figure 2 illustrates DJM working system indicating Binder Feeding Plant side and Mixing Machine side respectively.As typical soil mitigation method, many projects related with rivers and roads and city development has required DJM technology. The total number of the projects applying DJM has exceeded 5,000 with the total treated soil volume more than 32,000,000 m3 by the end of fiscal year 2013."

Jan 1, 2015

By Abid Adekunte

"In recent years, developers have had to deal with complexities associated with numerous cases of deep basement construction in built-up areas. Design and construction of deep excavation support systems in urbanised zones come with many technical challenges. Restricted working spaces often render the use of temporary struts as wall restraint systems unpopular, as working space needs to be maximised. Also, tie-back anchors are often inapplicable due to the existence of adjacent structures. Therefore, developing alternative restraint systems for deep basement structures in builtup areas is becoming increasingly important to the present day basement engineer.This paper is centred on the design, construction and monitoring of enabling works for deep basement structures on three sites in the United Kingdom and Republic of Ireland. Traditional tieback anchorage and propping systems were inapplicable on the sites. As alternatives, separate novel wall restraint systems were developed and adopted, to enable excavation on each of the three sites.Performances of the novel wall restraint systems, as well as the responses of adjacent structures were monitored. Numerical modelling and field monitoring results show the three alternative wall restraint systems to be safe and effective. The paper also highlights the advantages of the novel solutions over conventional methods.INTRODUCTIONRecently, deep basement structures have become popular components of urban building developments. As pointed out by Pearlman et al., 2004, this could be attributed to the inadequacy of surface parking spaces in urbanised zones, while underground parking facilities are also believed to improve both aesthetic and commercial qualities of urban structures.However, while the incorporation of basement structure into new urban development appeals to developers and architects, the engineering design and construction aspects of basement works typically come against a whole lot of complexities and challenges. As highlighted by Wong, 2002, engineering problems associated with basement construction in built-up areas are numerous, some of these include; complicated sub-soil conditions, dealing with excessive active pressures, complex temporary works, proximity of sensitive adjacent structures, high level hazards to construction workmen and surrounding community, inadequate working space, etc."

Jan 1, 2015

By Kevin Baumgartner, Steven Babcock

A landfill in Phoenix, AZ reached capacity and was graded over in the 1970s. The property was subdivided into lots in 2007 to create a business park. However, the challenging site conditions caused by the underlaying landfill put into question the feasibility of typical deep foundation systems. Several different foundation systems were evaluated to support the proposed development. The considered systems were: drilled concrete shaft, driven piles, drilled micropiles and helical piles. Soil stability, landfill decomposition, method of installation, flexibility of design, anticipated material, and equipment costs were considered. A system of helical piles with concrete pile caps and grade beams was selected. To mitigate unknown obstructions, holes were drilled through the landfill debris at pile locations and then backfilled with screened granular material. The helical piles were installed through these backfilled holes and advanced to bear in competent native material below the landfill. This method allowed for minimal disturbance of the landfill materials and provided a strong and adaptable foundation. Additional advantages of helical piles on this site include minimal installation vibration, no grout or concrete in the deep foundation, and capacity verification for each pile via torque correlation. Two load tests were performed to verify the design.

Sep 8, 2021

By Steven D. Scherer

The highest earthquake risk in the United States east of the Rockies is along the New Madrid Fault System, which extends for 193 km (120 miles) through the Central Mississippi Valley from northeastern Arkansas, through southwestern Missouri, western Tennessee and western Kentucky to southern Illinois. Historically, this fault has generated some of the most powerful earthquakes in U.S. history, notably three Magnitude 8 events in 1811. Apart from the West Coast, this region experiences more earthquakes than anywhere else in the United States, with more than 200 events recorded along the fault annually. These events are typically of much lower magnitude than those experienced in California. Most are too small to be felt. However, should a significant event occur, damage can be expected to be widespread because of the underlying geology. In recent years, earthquake preparedness and seismic upgrade of vulnerable structures has become a focus for a number of State Departments of Transportation, including those in Illinois and Missouri where there is a potential for future damage. This paper presents three case histories illustrating three different techniques used to retrofit interstate highway bridge foundations bearing on potentially liquefiable soils. Friction minipiles were installed at the approach span of the I-57 bridge crossing the Mississippi River near Cairo, Illinois to provide additional support to the pile caps in the event of liquefaction of the underlying sands during a seismic event. In St Louis, Missouri, rock-socketed minipiles were installed to increase the capacity of drilled shaft foundations supporting a section of Interstate 64. In Mounds, Illinois, compaction grouting was used to densify loose sand deposits beneath a pile-supported interstate bridge on I-57.

Jan 1, 2001

By Satyajit A. Vaidya

This paper presents a case-study in the design and construction of deep foundation element supported mats for two residential towers on an18,000-square-foot site in Brooklyn, New York. Based on site sub-surface conditions, conventional mat foundations bearing on medium dense sand, having an allowable bearing capacity of 3 tsf, were originally anticipated for the 16 and 25-story towers. However, when the tower shear walls were relocated to the edges of the mat foundations due to architectural revisions, the significantly increased mat edge contact stresses applied to the soil subgrade resulted in calculated settlements of a magnitude that would adversely impact the proposed structures and the neighboring/bordering lot-line building and rail transit subway structures. To address this issue, deep foundation element supported mats were designed for the towers. The design was performed as an iterative process involving structural SAFE and geotechnical Plaxis finite element computer analysis to develop a coordinated geo-structural model of the foundation system. Initial presumptive design values of 45 pci and 445 kips/inch were used for the modulus of subgrade reaction and minimum deep foundation element stiffness, respectively. The designed foundation system consisted of 40 and 60-inch-thick mat foundations for the 16 and 25 story towers, respectively. Initially, the deep foundation elements were designed as 50-foot-long, 14-inch-diameter elements installed to sustain a maximum individual compressive load of 250 tons. The final deep foundation element design was subsequently refined to consist of a 48-foot-long, drilled and grouted IBO Titan 103/51 element designed to sustain a maximum load of 167 tons. Subsequent field load tests on the deep foundation elements confirmed element stiffness ranging from 1,040 to 1,530 kips/inch, with measured mobilized side shear of about 29 psi. The mat foundation reinforcement was adjusted for the pile stiffness values determined in the field load tests, and the deep foundation supported mats were constructed. The two towers were subsequently constructed, and have performed successfully.

Jan 1, 2010

By Manasi Wijerathna, D. S. Liyanapathirana

"Deep cement mixing is a popular soft ground improving technology that improves the bearing capacity and settlement characteristics of natural soil. When Deep Cement Mixed (DCM) columns are installed attached to each other in a wall configuration, the walls are capable of resisting bending moments and shear forces in the direction transverse to the columns. Therefore, installing DCM walls beneath the embankment slope perpendicular to the alignment of the embankment is a proper solution to prevent excessive lateral deformations of the embankment. Previous research studies have shown that failure patterns of DCM column walls are different to failure patterns of individual DCM column rows, under lateral loads. This study investigates the failure patterns of embankments where DCM column walls are located beneath the slopes, with respect to DCM wall strength, DCM column wall width and the spacing between DCM walls. 2D and 3D numerical models developed using the ABAQUS/standard finite element programme, were used in this investigation. Results show that the DCM wall strength and width of the DCM wall have a significant influence on the failure mode and the critical failure surface of the embankment. 3D simulation results demonstrate that the failure due to soil extrusion between columns was less pronounced in embankments improved with DCM walls, due to the interaction between the DCM walls and the surrounding natural soil.INTRODUCTIONEmbankments constructed over soft ground are highly susceptible to global slope failure and excessive displacements due to combined effects of vertical and lateral loads beneath the embankment slope (Zheng et al., 2009, Han and Gabr, 2002). The overall stability of the embankment can be significantly improved by improving the soil beneath the slope of the embankment using Deep Cement Mixed (DCM) column rows or overlapped DCM column walls (Jamsawang et al., 2015, Larsson and Broms, 2000, Topolniki, 2004, Broms, 1999). According to the literature, the improved ground experience different failure modes other than shear failure, such as separation of columns, overturning, shear failure along the columns or dowel action (Broms, 1999). Some of the failure modes reported by Broms (1999) are shown in Fig. 1. The ultimate failure mode depends on the geometry and the strength of the improved ground (Jamsawang et al., 2015, Kitazume and Maruyama, 2006, Kitazume and Maruyama, 2007)."

Jan 1, 1900

By Mark R. Svinkin

"Construction equipment and operations usually produce soil and structural vibrations which may harmfully affect various structures and also the content of buildings and houses. The level of structural vibrations depends on a number of factors such as characterized sources of vibrations, soil conditions, and susceptibility of structures. There are certain knowledge and experience for managing the effects of construction vibrations which require implementation of condition survey of structures, information on construction dynamic sources and soil conditions at a site, evaluation of possible vibration effects on structure, calculation of ground vibrations before construction, use mitigation measures to decrease vibrations, and a choice of appropriate vibration limits. The paper presents the application of known concepts for assessment of vibration effects on structures from bridge constructions.INTRODUCTIONVibrations producing by construction activities such as pile driving, dynamic compaction of loose soils, demolition work, heavy construction equipment and trucks can affect adjacent and remote structures. Vibration effects on structures, sensitive devices and processes may create significant practical problems. Legal actions are often required for solutions of vibration consequences. The level of construction vibrations depends on dynamic sources, soil conditions at a site in particularly availability of soils with settlement potential, distances from the sources, parameters of waves propagating at a site and susceptibility rating of adjacent and remote structures. It is likely that intolerable structural vibrations from direct vibration effects of impact pile driving and resonant floor vibrations from vibratory pile driving may be induced in adjacent structures to construction sites.Foundation settlements resulting from soil vibrations in loose soils usually occur in the proximity of dynamic sources, but it is important that dynamic settlement may happen at various distances from the source. There are such examples. First, Kaminetzky (1991) mentioned a case history of building settlements developed at a distance of about 305 m (1000 ft) away from a pile driving site. Foundations of the buildings were underpinned on piles down to the tip elevation of the new driven piles to prevent building settlements. Second, Lacy and Gould (1985) shows that the peak particle velocity (PPV) of 2.5 mm/s (0.1 in/s) of ground vibrations could trigger dynamic settlements at distances up to 30.5 m (100 ft) from driven piles."

Jan 1, 2016

By Dennis Nottingham

"Increased interest in seismic soil liquefaction and preventative soil stabilization sets the stage for improved deep compaction methods using pile driving techniques. In 1971, L.B. Foster Company personnel patented a method of deep compaction using a vibratory pile hammer and pile probe. The technique had some success, but did not produce consistent results and thus found its way to obscurity. Other patents attempted to modify the technique by various probe modifications, but again without measurable improvement from a practical point of view. Solutions to economical deep compaction up to 100-foot depths particularly in saturated granular soils would have a great impact on the construction industry and new bulkhead structures being developed, thus PND was prompted into related research and development. The advent of higher horsepower vibratory hammers, coupled with PND engineers’ experiments, observations and measurements, led to an “H” pile probe design which has produced measured soil density improvements up to 250% using SPT “N60” values as a measure. Case histories of two projects involving extensive SPT soil sampling comparative measurements will be discussed along with findings that led to the compaction success. Applications to numerous modern “Open Cell” bulkhead projects will be presented and discussed.INTRODUCTIONNecessity often is the basis for innovation and such was the case for needed cost-effective deep soil fill compaction in Open Cell bulkheads where granular fill below water levels was often placed.Open Cell bulkheads were developed by PND Incorporated starting in 1980, for the express purpose of meeting client demands for an economical, easily constructed, extremely strong structure. Earth-filled structures historically have had a long history of problems with stability, scour and settlement.Open Cells are flexible steel sheet pile membranes supported by soil contact with embedded tail anchor walls.This concept creates an integral reinforced soil system. The result is a structure that can withstand large settlement and support a variety of very large loads. In effect, viewed from above the structure becomes a series of U-shaped horizontal membranes that require no toe embedment for stability. The Open Cell bulkhead is constructed of only three components: flat sheet piles, fabricated connector wyes and anchor piles. Compared to alternative structures, several cost savings are realized from this land based construction such as, reduced sheet pile area, greater construction tolerance, minimal pile penetration, and simplified backfilling procedures. In seismic regions or weak soils, the tail walls can be extended as required to guarantee fill mass stability."

Jan 1, 2005

By Antonio Kodsy, Lutful Khan

A research was carried out to test the possibility of reducing the pullout resistance of metal sheet piles driven in clay soils using Electrokinetic (EK) conditioning. The hypothesis was applying an electric gradient for a certain period of time should reduce the adhesion between the clay soil and the sheet piles. Tests were conducted on bench scale thin stainless-steel metal plates embedded in pure kaolinite clay, and mixtures of kaolinite clay and sand. The pullout resistances were determined after 20, 40, and 60 minutes residence times of steel plates in the soils before and after EK conditioning under an electric gradient of 1500 V/m. In kaolinite clay, the pullout resistance showed linear reduction with the duration of EK conditioning and about 60 % reduction in pullout resistance was observed after 60 minutes EK conditioning. For the kaolinite-sand mixtures, the pullout resistances were reduced by about 70% and 80% for 20% and 30% sand contents respectively after 20 minutes EK conditioning and showed no significant improvement with the increase in conditioning duration. It was concluded that the proposed electrokinetic conditioning process could potentially reduce the pullout resistance of metal plates embedded in clay and clayey soils. SHEET PILE WALLS Sheet pile walls are typically used at waterfronts as retaining structures or during the construction phase to shore the soil and avoid collapse of the excavations. When used as permanent structures, sheet pile walls are not removed after the completion of the project. However, as temporary support, they are extracted after the completion of the project and reused. In pure clay soils the extraction processes often becomes a challenge requiring very large pullout forces which could damage the sheet piles. There is a research need for developing an efficient method of sheet pile extraction from clay soils addressing the issue of pullout force reduction. However, very few researches have been conducted regarding the extraction techniques of sheet piles and their economic effect on the cost of a project. In this study a novel method for reducing the pullout resistance of sheet piles in clayey soils using electrokinetic conditioning was explored. The hypothesis of this research is that the electrokinetic process in soil/water system, specifically electrophoresis and electroosmosis, could be used to loosen the sheet pile walls embedded in cohesive soil and hence reduce the required force of extraction. The aim of this study was to test this hypothesis through laboratory tests carried out on steel plates embedded in cohesive soil samples. The pullout forces of the steel plates before and after varied duration of electrokinetic (EK) conditioning were evaluated and compared. The process was also investigated for clay-sand mixtures.

Jan 1, 2019

By Scott A. Walker, Gabriel J. Alcantar, Brian Zuckerman, Ramin Golesorkhi

"The new San Francisco 49ers Levi’s Stadium is part of the next generation of sporting facilities. Constructed in Santa Clara, Calif., the new structure has 68,500 open-air bowl seats and includes a 7- story tower housing more than 150 suites. The overall project includes the stadium structure, elevated open pedestrian walkways, commercial community space, three new pedestrian bridges and improvements to the adjacent light rail station. Sustainable design for the project includes a green roof, photovoltaic panel and a ground source geothermal system. Stadium-wide next-generation Wi-Fi capability is another feature. The design-build project team included HNTB (project architect), Magnusson Klemencic Associates (MKA, structural designer) and a joint venture of Turner Construction and Devcon Construction (TDJV, general contractor).During preconstruction, the 49ers’ original design team and the design-build team formed later worked together to facilitate communication and provide continuity. This helped to meet the project’s aggressive schedule. Working directly for the 49ers, with the design-build team, Treadwell & Rollo (T&R) served as the geotechnical engineer of record for the project from preliminary to final design and through construction. Although not contracted directly to TDJV, the stadium ownership encouraged direct interaction between T&R and TDJV and improved responsiveness to geotechnical issues during design and construction.Subsurface ConditionsThe new stadium lies within the Santa Clara Valley, a deep alluviumfilled basin resulting from historic movement on the active and potentially active strike-slip and thrust faults that bind the valley. The valley is filled with Holocene age (approximately 11,000 years old to present) alluvium, consisting of levee and basin deposits, with bedrock more than 750 ft (229 m) beneath existing ground surface. The stadium site is between two of the highly-active faults in California, the Hayward Fault 6.8 mi (11 km) northeast, and the San Andreas Fault about 11.8 mi (19 km) southwest."

Jan 1, 2014

By Michel Bustamante

The Arbre viaduct, 200 metres long, is the most important structure on the Belgian portion of the High Speed Train line between Paris and Brussels. The particular geotechnical conditions of the soil with carboniferous limestone affected by karstic phenomena, has prompted the designer to found the viaduct on systems of high capacity vertical and batter micropiles. The design of the working micropiles was validated by full scale tests performed on instrumented micropiles. The size of the structure and the deformation criteria to be met when HS trains are crossing the viaduct, together with the lack of references for such innovative structure, called for monitoring the movements of the piers as soon as the link was open to traffic. The authors report on the results of loading tests on micropiles and the results of settlement structure monitoring for a period of 4 years. Settlement of the foundation is estimated taking into account the group effect.

Jan 1, 2002

By Kenneth Gavin, Weichao Li, Paul Doherty

"The lateral load capacity is one of the most important issues to be considered in designing piles to resist berthing loads, ship impact forces and for monopiles used in the offshore wind sector. A number of semi-empirical design approaches are available to calculate the ultimate soil resistance and assumed soil reaction profile along the piles’ embedded depth. In order to investigate the response of monopiles to lateral loading, a series of field experiments were conducted on instrumented steel pipe piles. Two lateral loading tests were performed on model piles with a diameter, D, of 340 mm and embedded depth, Lem, of 2.2 m, giving a Lem/D ratio similar to those adopted in the offshore wind sector. The piles were driven into dense sand at the University College Dublin geotechnical test bed site in Ireland. 10 pairs of strain gauges were installed on each model pile along the embedded depth at 10 levels to capture the load transfer and bending moment within the piles. The deflection and rotation at the model pile head were measured by Linear Variable Differential Transformer (LVDT) and inclinometers. The tests results were used to perform a detailed evaluation of current design methods. In the final section, discussion on the determination of the ultimate lateral load capacity for monopile design was conducted. IntroductionA pile’s lateral load capacity is determined, for design purposes, by two conditions: 1) the ultimate lateral load, Fu, divided by an appropriate safety factor; and 2) the load according to the maximum lateral deflection that the support structures can sustain. In view of the first condition, design methods to calculate the ultimate load were developed for piles used in the offshore oil and gas sectors, which tend to be much more slender than monopiles used in the wind industry. The purpose of this study was to investigate whether these design methods provide reasonable estimates of ultimate capacity, for short rigid monopiles.The methods to determine the ultimate lateral load generally follow three steps: 1) determine the ultimate soil resistance, Pu, along the pile embedded depth; 2) adopt the most appropriate soil reaction profile, Pz, along the piles embedded depth when the pile subjected to the ultimate lateral load condition (four of the most popular ones are depicted in Figure. 1); and 3) ensure equilibrium of lateral forces (see Equation 1, symbols are listed at the end of the paper) acting on the pile and bending moments (see Equation 2) about a point in pile is employed to determine the ultimate lateral load."

Jan 1, 2015

By Rajarshi Pramanik, Nirjhar Dhang, Dilip K. Baidya

"This paper performs the reliability evaluation of pile foundation under vertical loading condition using the concept of fuzzy set theory. The uncertain parameters are expressed as fuzzy numbers. Monte Carlo simulation technique in conjunction with fuzzy set theory and fuzzy reliability index approach are implemented in evaluation of the probability of failure of pile foundations. The results are validated through some well established methods such as, First Order Reliability Method (FORM), Second Order Reliability Method (SORM), and direct Monte Carlo Simulation (MCS). Response surface method (RSM) is used to approximate the original limit state equation through second order polynomial. The effect of the position of the water table is also highlighted. Finally, the effect of the variation of applied load is examined and it is observed that the fuzzy reliability analysis gives more conservative estimate of failure probability than the other methods.INTRODUCTIONCivil engineering structures, such as high rise buildings, bridges, offshore platforms etc. are always subjected to vertical as well as horizontal loads. To support these structures, pile foundations are generally the solution in most of the situation. It transmits load from the superstructure to soil at a reasonably great depth. This transfer may be by vertical distribution of the load along the pile shaft or a direct application of load to a lower stratum through the pile tip. Different methods are available to estimate the capacity of piles embedded in different types of soil and under the application of vertical and horizontal loading. To consider the variability in soil and other unforeseen able situation, generally a reasonable value of factor of safety is used to estimate the designed capacity of the pile. Recent developments have shown a trend to place the treatment of uncertainty on a more formal basis, in particular by applying the results of reliability theory to geotechnical engineering. Keeping in mind the importance of pile foundation in the engineering structures it is essential to maintain a high structural safety which result in increase in reliability. The probability theory has been proved to be a powerful tool for representing variability in mathematical models. The variability associated with soil parameters and the modeling uncertainties are needed to be considered for the reliability assessment purpose.Recent development (Zhang et al. 2005; Misra and Roberts 2006; Haldar and Babu 2008; Basu and Salgado 2012; Teixeira et al. 2012; Pula and Rozanski 2012; and Chan and Low 2012) showed that the reliability analysis of pile foundations subjected to axial as well as lateral load has been one of the important current research topic in geotechnical field. Probabilistic based performance criteria were quantified for a single pile and pile groups in cohesionless soil by Eloseily et al. (2002). A p-multiplier approach was incorporated into the analysis to modify the p-y curve for a single pile to obtain the p-y curve for individual piles in a pile group. A statistical analysis of set up capacity of pile was carried out from the database of a large number of pile testing data in clay by Yang and Liang (2006). Load and resistance factor design (LRFD) using FORM was used for examining the different load and resistance factor for different target reliability index. Limit state analysis of drilled shaft was performed by Misra and Roberts (2006) in probabilistic framework. The fuzzy based reliability analysis (Dodagoudar and Venkatachalam 2000; and Park et al. 2012) of the earth slope was reported in the literature. Dodagoudar and Venkatachalam (2000) presented a new approach, called fuzzy point estimate method (FPEM) for reliability evaluation of earth slope. Park et al. (2012) reported a hybrid approach, fuzzy set theory in conjunction with Monte Carlo simulation technique, to determine the failure probability of earth slope. Second Order Reliability Method"

Jan 1, 2015

By Ronald E. Walkington

The U.S. Department of Energy (DOE) is building the world's newest accelerator-based, pulsed-neutron system, called Spallation Neutron Source (SNS). The facility, located in Oak Ridge, Tennessee, is a partnership of six DOE national laboratories - Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge. Oak Ridge has the responsibility for managing the partnership and ultimately operating SNS. SNS will provide opportunities for up to 2,000 researchers each year from universities, national laboratories and industry from around the world for basic and applied research and technology development in the fields of materials science, magnetic materials, polymers and complex fluids, chemistry and biology. When completed, this state-of-the-art research facility will provide neutron beams that are 12 times more intense than any other such source in the world. Most of the world's neutron sources were built decades ago. Therefore, it is easy to understand how SNS will provide new research opportunities unavailable elsewhere, and at the same time restore United States leadership in neutron sciences. Neutron scattering research provides valuable information about materials that cannot be obtained through microscopy, X-rays, spectroscopes, or other techniques. The information gained from neutron scattering research leads to improved materials that are used in high-temperature superconductors, powerful lightweight magnets, aluminum bridge decks, jet aircraft, compact and computer discs, magnetic recording tapes, shatter-proof windshields, and many other applications. SNS is like a flashing strobe light providing high-speed illumination of an object and will record the structure of physical and biological materials from plastics to proteins. Because neutrons have no charge, they can penetrate more deeply into materials than do X-rays, light, or electrons and thus reveal bulk structure and properties of materials. SNS will help to understand and "engineer" better materials and the manufacture of better products at the atomic level. Our high-technology society demands new materials that are stronger, lighter, and cheaper yet perform well under severe conditions. SNS, which is designed with the future in mind, will be the leading neutron research facility for many years to come.

Jan 1, 2001

By Filippo Leoni, Wesley Schmutzler

"The LPV-111 East Back Levee Improvement Project lies along the Gulf Intracoastal Waterway (GIWW) in Orleans Parish of New Orleans, La., and is an essential component of the New Orleans Hurricane Protection System. The Hurricane Protection Office of the U.S. Army Corps of Engineers (USACE) attributed failure of the New Orleans East levees system to overtopping, erosion and subsequent breaching of LPV-111 along the GIWW, as well as other sections of flood protection during Hurricane Katrina in 2005. The existing levee suffered extensive damages from Hurricane Katrina, such that the USACE elected to provide earth stabilization and to rebuild the levee sections. Due to the adverse geotechnical properties of the foundation soils, the Corps deemed ground improvement necessary to stabilize the new levee and to limit its footprint. Wet Deep Mixing Method (DMM) was selected as the most suitable technology for this task.ChallengesDesign: This reach specifically protects East New Orleans and the Bayou Savage National Wildlife Refuge, the largest urban wildlife refuge in the U.S. and home to several threatened or endangered species of birds as well as many reptiles, amphibians and small mammals. The Corps chose DMM due to the sensitivity of the protected marshlands and because the method limits the footprint of the raised levees. The increase in the load bearing capacity of the treated soil significantly decreases the footprint necessary to attain the required height increase. This limitation required the new levee to have steep slopes, drastically increasing the surcharge on foundation soils characterized by overall poor geotechnical properties (soft clays and peats). The design also considered the increased horizontal stresses on the levees due to the extreme storm surges during a hurricane.The design of the 1.6 m diameter (5.25 ft) DMM elements called for overlapping them to form a double auger element that formed buttresses perpendicular to the levee alignment. The contractor installed the buttresses at a maximum on center spacing of 4.7 m (15.5 ft). One additional double auger DMM element was midway between consecutive buttresses at the centerline of the levee to further help prevent settlement (Figure 1)."

Jan 1, 2013

By Jeremy G. Kress

We propose the discrete element method (DEM) as a complimentary alternative to analytical solutions and FEM models for the analysis of pile response. DEM is a novel approach to the engineering design of deep foundations which can be used to provide insight into the mechanics of soil-soil and soil-structure interaction. It is common to use analytical, empirical, and semi-empirical methods to predict pile behavior, where if granular properties, pile length, or load orientation change, then significant adjustments are made in the design sequence. DEM provides a more uniform approach in granular soils. Based on constitutive force-displacement relationships and laws of motion in rigid and elastic bodies, few changes must be made for a wide variety grain types, pile types, embedment, and load orientation. Preliminary results for simulation of a single pile are qualitatively consistent with results from conventional design procedures and also provide significant information not available from other analyses (e.g., local information about interface failure during shear). Importantly, these analyses are portable to a variety of pile types and installation procedures, which may not be the case for empirical approaches. Given consistent increases in computing power and rapid advances in model speed and sophistication, the DEM should prove to be a robust method for design and the analysis of pile response in granular soils.

Jan 1, 2010