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By Matthew D. Marks

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

Jan 1, 2017

By C. Vipulanandan

It is critical to monitor the ground conditions during excavation and drilling of boreholes during construction to identify possible changes in the soil and rock formations. Drilled shafts are increasingly used as foundations to support structures, bridges and other facilities in geomaterials such as soft-rocks and hard clays. Locating the bottom of the borehole during construction with the required design strength is critical. Hence developing a simple device that could be easily adapted/used with the drilling tool was of interest in this study. Determining the shear strength of the geomaterial in the borehole and at various elevations including the bottom of the borehole can lead to better quality control of construction by identifying the various layers based on strength. In this study, a down-hole penetrometer (DHP-CIGMAT) was designed, built, calibrated and tested in the field to determine its effectiveness in measuring the strength of soil/soft rock in the boreholes. Based on limited field tests, linear correlations between geomaterial strengths and DHP-CIGMAT deflection have been developed. The DHP-CIGMAT can be used to identify soils and soft rocks.

By Louis Donolo

New buildings in today's urban environment, especially in down-town areas, invariably involve the construction of multiple level basements. Used for parking, storage and commercial space, these underground structures normally extend 30 to 50' and more below grade and, to make optimum use of expensive land, they usually occupy the full site right up to street/sidewalk and property lines. SOIL SUPPORT SOLUTIONS Building these basements requires vertical excavation, and consequently, a temporary soil support system which will eventually be replaced by the permanent foundation walls of the structure.

Jan 1, 1987

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 H. F. Cowie

Britain's first pressurised water reactor (PWR) Nuclear Power Station is now under construction at Sizewell on the Suffolk coast. A linear cut-off wall was proposed to ensure that the drawdown of water to some 14m below sea level in the overlying sands during construction of the new power station would not affect the existing adjacent nuclear power station. The low permeability cut-off wall was constructed by diaphragm walling techniques by excavating a continuous deep trench supported by bentonite mud and then dis­placing the bentonite by a plastic concrete to form the "impermeable" membrane. The paper describes the automated digging apparatus ("Hydrofraise") with the extensive support facilities required to achieve completion within programme, control methods used to obtain the high vertical tolerances and the properties of the plastic concrete and the production plant used for its production.

Jan 1, 1989

By R. T. Stain

Dynamic methods of load testing piles using a drop hammer to generate the input force have been in use for many years. These systems are based on the wave equations developed at the Case Institute of Technology, Cleveland, Ohio in the late 1960's and are well documented. Such tests are generally restricted to preformed driven piles, the driving hammer being a convenient means of generating large input forces. In 1979 the CEBTP (France) was sponsored by the FNTP (Fédération Nationale des Travaux Publics) to undertake research into existing classical methods and to develop a test that would be equally applicable to bored cast in place piles. The result of this research programme is a methodology known as SIMBAT, and which was included in a series of class A prediction trials in Belgium in 1987 (Refs 1 & 2, Paquet 1987, 1988). The purpose of this paper is: a) to examine the type of 'dynamic'/'static? load test correlations that can be obtained. b) to highlight the differences between the classical' methods and the 'SIMBAT' technique.

Jan 1, 1989

By Bas R. Hemmen

GeoBrain is a facility at GeoDelft with the purpose to provide society with all relevant geo-engineering knowledge and experience in a structured way. On the basis of the available knowledge and experience engineers, decision makers and construction supervisors can come to a fast, reproducible and objective choice, taking into account the consequences. The paper presents examples from the GeoBrain experience databases and forecasting models developed for foundation engineering and directional drilling, or: "GeoBrain Foundations" and "GeoBrain Drilling". GeoBrain is closing the gap between theory and practice. It is aimed directly at reducing uncertainty and the costs of failure, thereby increasing the quality of profession and minimising the risk in geo-engineering works.

Jan 1, 2006

By Martin C. Jones

This paper outlines the development of small diameter grouted piling, to deal with foundation problems in difficult soils conditions and in very restricted access areas. A number of applications are outlined to show the way in which these piles have been used over the last sixteen years in Canada. PICKERING GENERATING STATION - ONTARIO HYDRO UNDERPINNING OF SCREENHOUSE - TRASH DISPOSAL AREAS Between 12th July and 29th September 1971, 40 small diameter grouted piles were installed in the screenhouse at Pickering Generating Station. Access was extremely restricted as the screenhouse had been completed and the majority of mechanical equipment had been installed. The two ends of the screenhouse had been built on granular fill which overlies till and shale bedrock and settlements had been observed which it was decided had to be halted even though the rate of subsidence had decreased. Two diamond drills were employed to install 8 inch

Jan 1, 1987

By Liqun Liang

Various nondestructive testing (NDT) inspection methods are available to evaluate the structural integrity of cast-in-place shafts. The widely used methods include Cross Hole Sonic Logging Testing and Low Strain Testing. Due to its advantages such as low cost, easy operation, quickness and flexibility (no need to plan ahead and prepare inspection tubes or other devices), Low Strain Test is frequently specified in quality assurance programs of many countries or when doubts arise as to the integrity of the finished shafts/piles. The method is well suited for small to middle sized shafts. However it is an indirect NDT testing method and has certain limitations. Data interpretation requires proper training, experience and judgment and, therefore, inconsistent conclusions and reporting may be provided by different testers. To avoid or reduce such inconsistencies, it is best to follow a standardized data interpretation and record classification system. In this paper, a new classification method is presented with examples. A step-by-step data evaluation and interpretation procedure is proposed with examples of real cases to help understand the LST data. The paper also makes recommendations for measures to be taken when anomalies are detected in tested production piles.

Jan 1, 2011

By David P. Sauls

Design-build contract delivery provides unique opportunities for efficiencies in pile foundation design and installation. The Louisiana Department of Transportation and Development (LADOTD) US Highway 90 at Louisiana State Highway 85 (US90/LA85) intersection was contracted under the design-build delivery system, in part to take advantage of these efficiencies. As one of five projects recognized by the Design Build Institute of America (DBIA) when it honored LADOTD as its 2011 Transportation Owner of the Year in the highway/bridges category, the design-build method provided a way for this project to be ?shovel-ready?, which enabled the LADOTD to secure American Recovery and Reinvestment Act (ARRA) funding. This paper describes the benefits this project gleaned from the design-build process, which included synergy, schedule, design and construction efficiencies, and team building. Interlaced with design and construction of precast prestressed concrete (PPC) piling in compressible southern Louisiana soils, the design-build process rapidly translated computations to cost and schedule savings. A robust quality assurance program using Pile Driving Analyzer (PDA) equipment to evaluate pile set-up provided expedited acceptance of bridge bents and advanced construction schedule. Data evaluation includes analyses of PDA data obtained from 1-hour, 24-hour, 7-day, 14-day and 6-month restrikes of the project test pile.

By M. Mets

Pile foundations have been used in Estonia since the beginning of 1960's. To evaluate the capacity of piles nearly 2,500 pile tests and 1,800 pile loading tests Have been carried out. The pile foundations of nearly 150 houses are under settlement observations.

Jan 1, 2000

By Walter Ensinger

Working safely means working cost-effectively. Every "dangerous occurrence" and - even more so - every industrial accident causes disruptions in the planned course of construction. Besides moral and legal obligations, economic aspects are therefore also factors motivating increased efforts towards optimal prevention: improvements in work safety and protection of health are wise investments! Ever since its earliest days, the European Federation of Foundation Contractors (EFFC) has made this subject one of its key objectives and therefore set up a Safety + Environmental Working Group, in which experts from the member organisations exchange national experience and develop proposals for "best practices". The paper presents current developments and results from the work of the S+E WG with particular reference to the project "Ideas for Safety Improvement".

Jan 1, 2006

By M. Makarchian

Existing buildings sometimes experience excessive settlement under their design loads, or due to increased foundation loading, if a change of building use is required. One of the oldest and widely numerical study has been carried out of a simple idealised problem of an underpinned rigid circular foundation to better understand the behaviour of pile used for underpinning and load transfer mechanism from an existing foundation to the underpinning piles. The finite element method has been used for this analysis, with the soil treated as a two-phase elasto-plastic material. It is found that the effect of the length of the pile becomes more significant as pile length increases. As would be expected, the earlier the pile is installed, the less is the final settlement.

Jan 1, 1996

By Douglas G. Baker, Jason K. Braund-Read, Megan R. Sheffer

"Mica Dam, owned by British Columbia Hydro, is an 820 ft high earthfill embankment dam that was completed in 1973. The dam consists of a thin central impervious till core supported by upstream and downstream compacted sand, gravel and cobble shell zones, founded on bedrock and valley bottom alluvium deposits. In 2012, a project was started to install new piezometric instrumentation within the dam’s foundation and downstream shell zone.Deep drilling in large embankment dams is very difficult and requires careful planning to select a methodology capable of reaching the target locations, while ensuring that no damage is done to the surrounding dam fill zones. At Mica Dam, the drilling could only be carried out from the Dam Crest and drillholes had to be carefully oriented to avoid intersecting any existing dam instrumentation. The drilling work therefore required angled drillholes, at depths of up to 855 ft, through heavily compacted sands, gravels and cobbles, and to significant depths below the standing water table.During the planning stages for the Project, in early 2013, the preferred drilling method was selected and a drilling contractor was engaged for the drilling work. Critical dam safety concerns were identified and addressed during the design stage of the Project with the drilling contractor, so that risk mitigation measures and response plans could be effectively developed.This paper explains how background information and prior drilling experience influenced the final design and implementation of the drilling techniques used in 2013 to successfully drill the deep holes and carry out the piezometer installations in Mica Dam. Drilling procedures, instrumentation design and installation methods, as well as risk mitigation measures, are discussed."

Jan 1, 2017

By Sangseom Jeong, Moonkyung Chung, Junyoung Ko

"Abstract The plugging effect of open-ended piles in sandy soil is analyzed by full-scale field test and plugging measurement. PLR (plug length ratio) measurement data from 144 field cases are analyzed with pile diameter. Based on the plugging measurements, PLR of open-ended piles which have above 1000mm diameter is predicted to be above 0.9. Through plugging measurements, a new empirical method is suggested for quantifying the plugging effect of open-ended piles. The proposed PLR equation is possible to predict the behavior of soil plug in the preliminary design stage. In addition, in order to investigate the behavior of the soil plug of open-ended pile, field load tests are performed on instrumented three piles driven into sand. It is obtained that the resistance components of open-ended pile are separated by double-walled pile system. It is found that inner shaft capacity is developed nearby pile tip. However, upper soil plug did not influence the inner shaft capacity. Also, it is found that all test piles are floating piles and unplugged condition because the sum of inner shaft capacity and outer shaft capacity is calculated about 58 to 76% of the ultimate bearing capacity.INTRODUCTIONIn Korea, a number of huge construction projects such as harbor terminals, offshore grand bridges, and lifeline systems are progress in urban and costal area. In these areas, steel pipe piles are frequently used to support high-rise buildings and heavy weight structures for ensuring structural safety rather than serviceability limit capacity. Also, steel pipe piles are frequently used in civil engineering structures because they have many advantages such as high-load bearing capacity, light weight and outstanding workability. The mega foundations of grand bridges and high-rise buildings are required in geotechnical engineering. Large diameter driven piles are frequently used in several projects.Many specifications such as API, FHWA and AASHTO have been reported as a design guideline of plugging effect, however , the current design method for plugging effect of steel pipe piles are mainly based on the our knowledge derived from observation of the model test or the small diameter pile load test. Therefore, these specifications have limitation to apply the large diameter steel pipe piles.Much work has been done to study the plugging effect by many researchers. Yamahara (1964) reported that soil plug has been modeled as a thin disk element as shown in Figure 1, since the increment of radial strain of the soil plug can be neglected due to high rigidity of the pile compared to that of the soil plug. Klos and Tejchman (1977) reported that the end bearing capacity of open-ended piles was almost equal to that of a closed-ended pile when penetration depth of pile was above 15times the pile diameters by model tests. Paikowsky and Whitman(1990) reported fundamental studies on mechanism of plugging effect in sand. Paik et al. (2003) reported that empirical relations for plug load capacity, annulus load capacity, and shaft load capacity of open-ended piles are proposed based on the model pile tests. As discussed above, much work has been done in the area of plugging effect. But little work has been done to study the plugging effect by full scale field tests."

Jan 1, 2014

By David E. Albus, Ahmadreza Mortezaie, Bidjan Ghahreman

The structural evaluation of seismic performance of an existing hospital in Long Beach, California, required spring constants of foundation elements. The structure included support by deep foundation elements comprised of belled (underreamed) caissons. The available relationships in the governing building code (ASCE41-13) to compute axial stiffness is not applicable due to the belled configuration of the caissons. The large diameter of the bells required consideration of the foundation medium to the axial stiffness; a detail not clearly described in ASCE 41-13. Furthermore, prescriptive equations in ASCE 41- 13 used to estimate lateral stiffness only consider pile groups with the assumption that the only source of lateral stiffness is the axial reaction of individual piles. These assumptions were invalid for the project at hand where all caissons are configured as single foundation elements, not a pile group. In the present work, the approach taken to estimate seismic stiffness of single-belled caissons is described which accounts for the elastic behavior of the foundation medium below the bell base and lateral behavior of single-pile shafts. Results of the work provide a more satisfactory derivation of the spring constants consistent with current modeling methods. INTRODUCTION Seismic evaluation of an existing hospital in Long Beach, California, required geotechnical investigation followed by site-specific ground motion analysis. This evaluation was required by the Office of Statewide Health Planning and Development (OSHPD) in order to meet the requirements of the Structural Performance Category 4D (SPC-4D) published as a part of the 2016 California Building Code, CBC (Section 3412A). SPC-4D utilizes ASCE41-13, as modified by OSHPD, and involves two seismic performance objectives: BSE-1E (20% probability of exceedance in 50 years) and BSE-2E (5% probability of exceedance in 50 years). Spring constants and capacities of foundation elements were needed for evaluation of the structural performance of the building subjected to these two performance objectives. Our review of the as-built foundation plans indicated that both shallow footings and caissons were used for support of the structure. The plans demonstrated that all caissons are belled (under-reamed) and are individual, i.e. not part of pile groups. In this paper, the subject site condition and foundation elements are described first. This is followed by details of assessing spring constants and vertical capacities for belled caissons. The new requirements of the 2016 CBC concerning the evaluation of critical facilities will likely entail evaluation of other structures with belled caissons due to the more extensive use of these foundations in the past. This paper proposes a method to address the conditions of individual belled caissons not explicitly considered in the current code provisions.

Jan 1, 2018

By G. Price

The Building Research Establishment installed a base load cell in a driven cast-in-place pile prior to it being tested under vertical load. The monitored base loads were found to be significantly less than could have been predicted by current design methods. The less than expected capacity was attributed to the drilling out procedure. An electro-level system installed in a second similarly formed pile, provided detailed information on the performance of the pile under lateral load. The information obtained was used to check several current design methods for laterally loaded piles. The findings show the potential dangers of attempting to improve design parameters from only limited performance data.

Jan 1, 2010

By Dilip Khatri

Helical pile anchors have gained acceptance over the past sixty years. Most recently they have been commonplace in the 20th century for the power utility industry in anchoring transmission towers, equipment platforms, street lighting, telephone poles, and radio tower applications. They have a strong proven industrial track record in these industries. As the cost of conventional deep pile foundations rises, the practical benefits of helical pile anchors becomes evident as a practical alternative. Noted for their uplift capacity, helical piles demonstrate equally strong compressive capacity as a structural foundation element. This paper summarizes the history, practical benefits, and technical requirements for helical piles. Significant structural testing has been completed at various universities. The practical benefits of these tests are discussed. One case example of proven performance is presented to demonstrate the advantages and disadvantages of helical pile anchors as suitable foundation elements.

Jan 1, 2003

By James A. Schneider

The successful installation of long piles driven into very dense sands relies on the occurrence of the reduction in local friction with increased pile embedment, a phenomenon known as ?friction fatigue?. The underlying mechanisms controlling friction fatigue are poorly understood, with some design methods including an adjustment for the influence of pile diameter while others do not. This paper back calculates the installation resistance of 0.356m to 2m (14in to 78in) diameter open ended piles driven into very dense sands using wave equation analyses. Cone penetration test data are used to link soil properties to installation resistance. The study illustrates consistent interpretation of a variety of case histories of open ended piles driven in very dense sands using newly developed analysis techniques and normalized parameters. Results provide information on methods for incorporating friction fatigue into drivability studies as well as a discussion of mechanisms related to pipe pile installation resistance in sandy soils.

Jan 1, 2010

By Bjöm Böhle

Top-down construction (or cut and cover construction) is providing important advantages when comparing with conventional construction techniques for commercial developments with deep basements, underground car parks or near surface infrastructure and traffic tunnels. Main features are substantially reduced restrictions to surface usage, avoidance of intervention with adjacent property, provision of rigid substructures resulting in minimal deforma­tions and settlements and, last but not least, accelerated construction pro­gramme. The present contribution illustrates the construction method in general and elaborates in detail on the special foundation works for a major urban commercial high rise development requiring a six level basement structure.

Jan 1, 2006