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By K. Viking

This article deals with some of the civil engineering related problems to be encountered when offshore wind energy projects transform from prototype offshore wind energy converter farms, developed and installed during the 1990?s, to commercial farms that?s currently planned to be built. The offshore wind energy converter (OWEC) installations encounter a wide range of problems, only partial of these are geotechnical. In Europe both onshore and offshore wind farms have, from a historical point of view, usually been founded by using the monopole technique, installed with traditional impact hammers, or by using gravitational foundations. However, the rapid development of bigger turbines and larger wind farms, together with increasing considerations of fatigue aspects, has lead to financial benefits of developing and exploring other foundation techniques. This paper reviews some Scandinavian experiences regarding critical components of the design phase in relation to connecting the superstructure to the ground, and some of the main considerations of how the loads applied to the structure are transferred to the surrounding soil.

Jan 1, 2013

By Sun Jiale

This paper presents a brief description of information construction technology for supported excavation to assure satisfactory performance of engineered system. As a successful example of application of the technique, quite a few troublesome problems, such as high groundwater level in soft ground and crowded buildings around the excavation, were solved satisfactorily in the construction of the new tower of Guangzhou Overseas Chinese Manison.

Jan 1, 1991

By R. Bellotti

The theory of cavity expansion in an infinite frictional soil mass whose strength is represented by a curved Mohr-Coulomb failure envelope has been used to predict with some confidence the cone resistance of a clean dry sand. Experimental data were obtained from cone penetration and pressuremeter tests on two sands, conducted in a large calibration chamber (CC) under carefully controlled placement and boundary conditions. A plane strain bearing capacity theory was developed, and to convert the results to axi-symmetric conditions, an empirical "shape factor" was used. In the paper, the theoretical background, experimental data, calculation procedure, and the results of the analysis are presented. In general, a reasonable validation of the cavity expansion approach to the bearing capacity of deep foundations has been obtained.

Jan 1, 1987

By Riad Diab

In 2018 the Caisse de Dépôt et Placement du Québec (CDPQ) awarded a $6.3 billion (U.S. dollars) design-build contract to the Joint Venture (JV) team NouvLR for the design and construction of one of the largest automated transportation systems in the world, called the Réseau express métropolitain (REM). The REM project is a 67 km (41.6 mi) light rail system with 26 stations linking downtown, the airport and the greater Montreal area in Canada. Out of the 67 km (41.6 mi) network, over 25 km (15.5 mi) is being constructed on a 650- span elevated structure founded on single drilled shafts socketed into rock. Optimizing the design of the drilled shafts was one of the main objectives of the geotechnical team, as it would likely result in shorter shafts that help significantly reduce the project costs. As part of the optimization process, three static axial load tests and two fully instrumented lateral load tests were performed, during the preliminary design phase, on sacrificial shafts to simulate the ultimate load level and validate construction procedures.

May 1, 2022

By James L. Vinson

Wilbur Smith Associates (WSA) has provided planning, engineering and construction oversight assistance to the Tennessee Department of Transportation (TDOT) for three construction projects intended to widen and improve segments of I-40 and associated interchanges in Knoxville, Tennessee. The projects are within the karst terrain of the Valley and Ridge Province. Subsurface conditions are characterized by an irregular rock surface coupled with differential weathering. Because of the projects? impact to local and interstate motorists, consideration was given to innovative planning, materials and construction practices that could accelerate construction. Two innovative deep foundation measures included rock-socketed pipe piles, which act as both foundations and substructure elements for a bridge?s interior bents, and the first widespread use of rock-socketed drilled shafts as bridge foundations on a TDOT project. The pipe piles were used at a site with significant cavities within the limestone bedrock. This resulted in design verification and constructability difficulties that required delays, but measures were ultimately employed to produce a sound foundation system. Over 110 drilled shafts have been constructed at sites with generally low solution activity. Relative to H-pile footings, which were included as an alternate foundation, they have apparently allowed accelerated construction at a competitive cost.

Jan 1, 2006

By Klaus Pöllath

The Netherlands RandstadRail project makes use of a large range of sophisticated geotechnical techniques to allow a shield driven tunnel to approach the central station of Rotterdam. This paper describes the construction of three deep excavation pits constructed with 1.2 m and 1.5 m thick diaphragm walls. Besides the presentation of the actual diaphragm wall activities special consideration is given to the break-in and break-out situations of the TBM into the deep excavations pits using sealing blocks and partly glass fibre reinforcement in the diaphragm walls.

Jan 1, 2006

By Drew Floyd

Five full-scale pile load tests were performed on pairs of PZ-22 sheet piles installed with a vibratory pile driving hammer. The sheet piling was installed in several locations in soil generally consisting of miscellaneous granular fills overlying soft organic silts, inorganic silt interbedded with sands and gravels, very dense glacial till and shale bedrock. The test program also included the use of tip tell tales to determine what capacity could be attributed to tip resistance and skin friction. During the design phase of the project, it was assumed that the capacity of the sheet piles driven with the vibratory hammer could be correlated with the rate of penetration. The correlation between vertical capacity and rate of penetration would be used as a basis for determination of a driving criteria from driving the production sheet piling. The sheet piling load tests demonstrated that it was not possible to correlate the capacity of sheet piling driven with a vibratory hammer and the rate of penetration. It was also demonstrated that the capacity of the sheet piles was directly related to the density of the soil at or just below the tip. The results also tend to agree with empirical equations provided by Meyerhof (1976).

Jan 1, 1989

By Shreyas Giridharan, Fursan Hamad, Sujith Gowda, Christian Moormann

"Pile installation in soil is a dynamic process which exhibits large deformation in the soil region. Experimental investigation of pile installation is both time and resource intensive. Numerical investigation can be a helpful tool for the analysis of the installation process. Furthermore, numerical analysis allows simulating various soils and loading conditions with ease. Finite Element Method (FEM) – a widely used framework for numerical simulations - fails to perform well for soil mechanics where large deformation and heavy material movement exists. In order to alleviate this shortcoming, Material Point Method (MPM), advancement to FEM has been used. In MPM, material points (particles) are used to represent the domain which carry the information and move over a fixed computational mesh where the governing equations are solved.In the present work, a variation of MPM, called CPDI (Convected Particle Domain Interpolation) is utilised which handles large deformation problems better than the classical MPM. Here, the material points are represented by a spatial domain which deforms according to the particle deformation. This eliminates stress oscillations while particles cross the grids. Implementation is validated and applied to pile installation in dry and saturated soil conditions. A 2D axisymmetric model is chosen, with penalty function method being used for evaluating contact between soil and pile. Sand is modelled via the hypoplastic constitutive description that takes into account large deformation, as well as small strain stiffness. From these simulations, various parameters like stress, void ratio and friction angle are studied.INTRODUCTIONOffshore piling is challenging in terms of testing and execution. Before the execution, predicting an efficient installation method requires study of various parameters, like soil conditions, type of loading, force requirement etc., and are the minimum parameters to be known beforehand. To obtain these parameters, testing a real scale prototype under different conditions is not feasible. Scaled model tests in lab can support in making certain decisions, but fail to replicate real behavior fully. Therefore, the need for a numerical simulation technique emerges, which can provide early predictions easily and accurately. This later can be extended to real scale tests, reducing the number of experimental investigation required.Simulation of displacement pile installation in sand involves large deformation due to penetration process, thereby making the application of FEM impossible, where large deformation causes heavy mesh distortions. Due to this, meshless methods are developed to treat large deformation in a better way. Among various meshless methods, Material Point Method (MPM) shows more applicability to geomechanical problems. This is mainly due to the ease of handling soil, structure and water in a unified manner."

Jan 1, 2017

By Sam X. Yao

The underwater concrete technology has historically evolved largely through a trial-and-error process of constructing marine works. Many outstanding examples exist of high quality concrete placed underwater. However, failures also occurred and led to excessive cost and/or schedule overruns. These failures were largely due to improper concrete mix design or improper placement. The problems may have occurred because proper underwater concrete construction techniques and experience have not been widely disseminated. This section focuses on technical issues of underwater concrete mix design, concrete production and placement, and quality control.

Jan 1, 2013

By Jon Sinnreich

Ensuring the accuracy of collected data during deep foundation static load tests is of paramount importance. Typically, pile head displacements are measured relative to a purpose-built reference system, which is assumed to be fixed. This study presents a simplified error analysis of this assumption, illustrates the potential magnitude of these errors, and proposes an improved method of pile head displacement monitoring.

Jan 1, 2009

By Michael D. Justason

"In January 2009, long-time competitors, Anchor Shoring & Caissons Ltd. of Toronto and Bermingham Foundation Solutions of Hamilton, joined forces to tackle one of the Greater Toronto area’s largest deep foundation projects: the West Toronto Diamond Rail Grade Separation. The two companies formed the “West Diamond JV” and succeeded in winning the contract from the Canadian National Railways. This deep foundations work was the first and most significant part of the $300-million-plus rail grade separation project. A big part of the job turned out to be dealing with local government regulations and citizens’ concerns with noise and vibration.The project is approximately 10 km (6 mi) northwest of downtown Toronto in an area of mixed-zoning including light industrial, commercial and residential buildings. The area is commonly called the “The Junction,” because of the heavy rail- traffic. The “West Toronto Diamond” refers more specifically to the railway junction where the North-South tracks of Canadian National (CN) Railway meet at a level crossing with the East-West tracks of the Canadian Pacific (CP) Railway. The goal for this part of the project was to convert the West Toronto Diamond into a grade-separated junction by depressing the CN lines under the CP lines, thus allowing commuter rail carrier, called GO Transit, intercity carrier VIA Rail, and CN freight trains to pass through the new underpass.Dawn Tattle, president of Anchor Shoring & Caissons says, “not only is the site in a densely populated area adjacent to homes and businesses, the crews worked adjacent to active rail lines with numerous trains passing daily. During the 7-hour working day, approximately 60 trains passed through the site in very close proximity to working crews.” Safety was paramount. While trains were passing through the site, it was a railroad requirement that all equipment and men stop working. In addition, at those times, all personnel were required to stay 6 m (20 ft) from the tracks and were required to face the tracks. For the faster commuter trains, this work interruption could last as little as 2-3 minutes, while interruptions caused by the slower freight trains could last as long as 25 minutes. The most disruption to the site occurred during the morning commute between 7 to 9 a.m., so work did not really get underway until after that time. Once work finally commenced the race was on to finish as much as possible before the afternoon commute – hence the shortened work day. The amount of disruption caused by the trains was a big unknown faced by the JV going into the project, but crews adapted quickly to the very unusual work environment"

Jan 1, 2012

By Marius B. Wechsler

There are considered deep piles which are fixed in blocks of rotating machinery foundations. A mathematical background is developed for determining the behavior of this kind of piles for motions caused by horizontal and vertical oscillations, as well as by roc-king and twisting. It is assumed that the piles come across a top soil layer of depth c, not capable of lateral support, and penetrate over a length b, in a bottom firm soil layer, or in a bottom soft soil layer in which vibrations can produce voids around the piles. With respect to b and c, as well as to the elastic properties of piles and soils, the analysis leads to the maximum bending moments and shear forces subjecting the piles, to the maximum lateral bearing on the bottom soil layer, as well as to the deflection of the pile and the displacement of the foundation block. The results of the performed analysis can be applied to seismic loads too, and they are illustrated by a numerical example.

Jan 1, 1987

By Lucien P. Weber

Over the last few years, increased customer demands as well as strong competition from substitute materials have accelerated the development of advanced technologies to improve both the performance and the cost-effectiveness of steel H-piles. On the material side, the development of an in-line heat treatment, combined with the most advanced steelmaking and rolling techniques, allowed to create a new generation of high-strength low-alloy steel grades, called HISTAR, achieving yield points up to 500 MPa (~72 ksi) and yet maintaining excellent weldability properties thanks to a low carbon equivalent. The topic of this paper is to illustrate the performance of H-bearing piles in HISTAR steel grades. In 1989, a major test program was started at different locations in Hong Kong, which is renowned for its difficult soil and severe driving conditions. After the successful completion of these tests, the HISTAR bearing piles were accepted by the local building authorities. Thanks to their cost-effectiveness, the HISTAR bearing piles have subsequently been used with great success in areas with appropriate soil conditions, especially in Asia and more recently in Europe.

Jan 1, 1997

By Rolf Katzenbach

Construction of drilled shaft foundations with the use of hydraulic oscillators and rotators to install temporary casing over the full depth of the shaft is described. The equipment and techniques were developed in the 1960?s in Germany and full-depth casing is now the predominant method of construction in Europe. Its use in North America is increasing. This paper presents an overview of full-depth casing methods and a summary of available load test data evaluated by the authors to compare the load transfer and capacity performance of shafts installed by various construction methods. Results demonstrate that load transfer and capacity of full-depth casing shafts are equal to or exceed that of shafts constructed by dry or slurry methods and that measured capacities are consistent with generally accepted design equations. The principal advantage of full-depth casing methods over other installation techniques is that the risk of defects in the shaft is minimized. Casing is able to penetrate into the ground under any geologic or groundwater condition when this technique is applied. Potential delays and cost overruns can thus be avoided and a safe, economical foundation element is created.

Jan 1, 2007

By A. V. Shroff

The Indian Standards code of practice for design and construction of underreamed piles contains provision for installing such piles in expasive soils. In recent years, a large amount of research work has been carried out in the analysis, design, construction and performance of underreamed piles in expansive soils. This paper suggests that the results of this research field tests should be included in the code. Various additions and modifications as well as deletions that should be incorporated in the code are discussed.

Jan 1, 1996

By Brian P. Waagner

Construction law in general and the law of deep foundations in particular continues to develop rapidly, particularly in the areas of risk allocation. Public and private owners are increasingly using contractual disclaimers to shift the risk of differing site conditions to contractors, and courts are increasingly willing to enforce these contractual devices. Perhaps also in an effort to control costs, public and private owners are turning to design-build contracting techniques. While design-build offers many advantages over traditional project delivery systems, it does not answer all of the risk-allocation questions that frequently arise. Even in design-build, problems with unanticipated subsurface conditions and defective design are not easily addressed. Finally, developments in electronic commerce present the potential to transform the construction industry.

Jan 1, 2002

By J. A. Elliot

Deep Mix-in-Place soil stabilisation is achieved by forming columns of soil/cement arranged to overlap by secant intersection. Alternate columns are constructed initially and infilled. The cementitious material injected is designed to retard the strength of the resulting mix thereby allowing satisfactory overlapping. Columns are constructed using a designed large diameter mixing auger mounted on a smaller diameter auger stem. This is firstly screwed to the design depth removing only such spoil as to enable penetration of the auger, and subsequently counter rotated and extracted in a predetermined mixing pattern and grout injection rate to ensure continuous and homogeneous treatment through each successive level. The process is performed whilst monitoring auger depth, grout flow and pressure. Cementation Piling and Foundations Limited used this technique to stabilise allu­vium and to facilitate the construction, by conventional techniques, of a circular pumping station pit of 10M diameter to 10M below ground level. The work was carried out within 3M of adjacent domestic properties, and on a very restricted site in Elland, West Yorkshire. Ground conditions consist of 2M of cohesive alluvium becoming water bearing and increasingly sandy and gravelly with cobbles which overlies the mudstones at 10.0m depth. Sandstones beneath formed an aquiclude to artesian ground water with the underside of the open excavation approxi­mately 1.0M from the top of this material. Peripheral treatment into the mudstone, coupled with pressure relief wells, proved successful and final excavation depth was achieved in "the dry".

Jan 1, 1989

By Ray. K. Filip

The concept of installing a steel sheet pile retaining wall into the ground by "pressing" has resulted in the development of various equipment solutions over the last thirty years e.g. Taylor Woodrow ?Pile Master', Giken 'Silent Piler" & Tosa 'Still Worker?. Dawson Construction Plant Ltd (DCP), have recently advanced the pile pressing concept with the introduction of their 'Push-Pull' system. This advancement offers significant improvements in the quality of installation compared with traditional pressing solutions but also greater versatility, higher productivity and, most importantly, generates new opportunities through a wider range of applications for "silent piling'. This paper will focus primarily on the use of the Push-Pull concept in the construction of a unique "integral" bridge in Milton Keynes, England. Finally, the paper touches on the development of quiet, vibration-less pile extraction equipment, which allows steel to be considered the foundation material of choice for truly sustainable construction. It is no longer acceptable to leave unwanted piles in the ground.

Jan 1, 2006

Jan 1, 1994

By Roderic A. Ellman

The new Woodrow Wilson Bridge (WWB) will replace the existing bridge over the Potomac River to connect Alexandria, Virginia to Prince Georges County, Maryland. The new WWB will extend approximately 1.1 miles across the river, with a 367-ft long bascule span in the main river channel where the water depth is about 36 ft. The subsurface soil profile consists of up to 50 ft of a soft organic silty clay layer that is very vulnerable to scour, underlain by a deep deposit of hard sandy clay. Foundation construction in the Potomac River required the use of cofferdams to allow structural concrete work to be performed in the dry. This paper will the present the types of cofferdams used to construct the foundations for the WWB replacement project. The bridge is primarily comprised of fixed spans in relatively shallow water and a bascule span over a navigation channel in relatively deep water. Foundation construction included the installation of 48? to 72? open end steel pipe piles and cast-in-place concrete pile caps. To achieve the desired bridge appearance, pile caps were required to extend below the water surface and below the existing river bottom in shallow water locations. Conventional steel sheet pile cofferdams with tremie concrete seal were used to construct fixed span, shallow water piers. Selection of deep water bascule span foundation cofferdams was governed by several factors including contraction scour, environmental considerations and cost. Potomac River cofferdams, i.e., relatively shallow depth cofferdams that are supported by the foundation piling were selected. This cofferdam system provided a shallow profile which minimized contraction scour and the amount of filling in the river. Design issues include load selection and cofferdam stability in very soft alluvial soils. Construction issues include erection sequence, tremie concrete mix design and placement procedures.

Jan 1, 2013