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By Geoffrey Birch

A skilled and efficient workforce is a pre-requisite for the success of modern construction companies. The drive for improved performance, innovation and best value must be matched by the enhanced skills of the construction personnel. Training has been accepted as one of the essential cost effective elements to achieve these goals. The foundation industry demands particular specialist skills and requires focused training for its dedicated operatives. The introduction and development of specific training qualifications for the foundation sector is providing significant benefits.

Jan 1, 2000

By S. F. Fu

The Charkhan Salt Lake area of the Chaidamu Basin in West China is characterized by soft super-saline soils with very high contents of soluble salts. From the engineering point of view, these saline soils are saturated, liquid-plastic and moderately to highly compressible lean silty clay and clayey silt. In the natural state, their allowable bearing capacity is only 60-80 kPa. As to the saturated lean silty clay, liquifaction in case of an earthquake of intensity 7 on the Modified Mercalli scale is considered likely. In order to improve the geotechnicai properties of the saline soils, stone colomn stabilization by means of vibroflotation was performed. As the geotechnicai properties of the soils are closely linked with the amount and composition of the soluble salt content, saline water with chemical content similar to that of the saline soils was used as flush fluid in the course of hole-making and column-forming, with a view to keeping unaltered the amount and composition of the salts in the soils and thereby precluding reduction in or loss of their strength. Systematic monitoring on the behavior of the foundation soils before and after the treatment and comparison of the numerical data thus acquired have shown good technical results, testifying to the effectiveness of stabilization of soft superealine soils by vibroflotation. As a result of the treatment, the allowable bearing capacity was increased one to two fold, accompanied by elimination of the liquefaction potential.

Jan 1, 2010

By Jom Gentry

Acrylamide chemical grout (C3H2NO) has been successfully used for over 50 years to control groundwater and stop infiltration. This paper will address three unique projects involving the control of groundwater with each study providing special circumstances and geological conditions: encapsulation of radioactive hazardous waste in the United States, a tailings dam for a large copper/gold mine in Argentina and 27 miles of leaking subway in Canada. The primary reasons for selecting acrylamide grout were based on the following characteristics: thinnest chemical grout on the market, a true solution grout which contains no suspended solids in the blended product, flexible gel set times, and a 362 year half-life in soil as determined by the U.S. Department of Energy.

By Rudolph P. Frizzi

"Abstract Pile design for building structures in the United States is typically performed by: 1) investigating and assigning engineering parameters to the respective ground bearing materials, 2) calculating ultimate pile to ground (geotechnical) capacity which is then reduced by a Safety Factor deemed appropriate by a registered Design Professional thereby arriving at an allowable pile geotechnical pile capacity, and 3) determining the required pile structural section using allowable pile section material properties. It is advantageous to use a Working Stress Design Method (WSDM) approach as one system of loads (service loads) are used in both the geotechnical and structural evaluation. There are a variety of methods used to determine the ultimate and allowable geotechnical capacity, and Building Codes often require a registered Design Professional to determine the appropriate method(s) and capacities. The International Building Code is the Code typically referenced in building design and construction in the United States. Structural design usually follows Building Code requirements and Allowable Stress Design (ASD) procedures. As design of the overlying structure typically follows a Strength Design Method (SDM) approach using factored loads, in some cases piling is first designed for pile-to-soil interaction using service loads, followed by evaluating the pile geometry for factored loads. Construction is the finalization and implementation of the designed piling. As such, project-specific technical specifications are typically developed by a registered Design Professional such that a project Owner can bid, buy, and instruct a Contractor as to the desired piling work and acceptance criteria. There are several Industry groups, including DFI, PDCA, ADSC, and ACI that provide guidance documents which the registered Design Professional can refer to in developing the piling technical specifications. It is the author’s opinion that the registered Design Professional is best suited to observe and verify the piling installation; many Building Departments require verification and documentation by a registered Professional as a condition of final acceptance.INTRODUCTIONPile design for building structures consists of: investigation, design, specification, and verification. In major metropolitan areas within the United States, Building Codes typically identify minimum requirements for each of the above steps. The International Building Code (ICC, 2012) is the Code typically referenced in building design and construction in the United States. Recognizing the ground conditions as well as piling construction means and methods can vary on a site-by-site basis, latitude is given to the registered Design Professional and Contractor to optimize the piling system for the respective project conditions. Field testing and quality control / assurance measures are typically implemented to verify the design intent is attained for the production pile elements."

Jan 1, 2014

By Luca de Sanctis

The analysis of piled raft foundations in layered soils may be performed by 3D finite elements or by approximate procedures. Among the latter, the code NAPRA (Russo, 1998) is based on the method of the interaction factors and accounts for soil layering by the so called Steinbrenner approximation. A comparison between the results of 3D FEM and NAPRA for some reference layered soil profiles shows that the approximation is fully acceptable for engineering purposes, provided the stiffness of the single pile is properly selected. The interest of the conclusion lies in the fact that the amount of work needed to model a practical problem by NAPRA is but a fraction of that needed by FEM modelling.

Jan 1, 2002

By Richard Deakin

This case study describes aspects of the design of bridge foundations using 320mm diameter steel tube piles in the vicinity of Montréal, Canada. In this area, these piles are a very commonly used and cost effective solution for deep foundations. Typically they are driven through thick Champlain Sea Clay to bear onto stiff, strong rock. However, in some locations there is a layer of glacial till between the base of the clay and the rock which cannot always be fully penetrated by the piles. There is currently little published information, about the bearing capacity of these piles in the local till, and this paper presents and discusses some pile-test data from a recent project. The nature of the glacial deposits in the study area is presented using information gained from published geological data, the project ground investigations and site observations. The design approach and assumptions are discussed, together with the aims and outcomes of preliminary field driving trials and pile tests. The paper then discusses the results of dynamic tests undertaken on production piles. Bearing capacity factors are back analysed from the dynamic test results and compared against values assumed within the design. Observations are made that designers of future foundations in similar conditions may find informative.

Jan 1, 2011

By Nuno Cruz

"The concrete overbreak estimation for bored piles provides the quantification of the shaft’s expansion beyond its theoretical volume. There are stability analysis methods that can be employed before and after concrete pour but as for the moment of decision, during pile cast, the most common method still consists in measuring the rising of the concrete level in order to compare its poured volume with the theoretical pile section volume. This is a determinant parameter to monitor, not only because it assesses the bored shaft stability but also because it represents a direct cost. When analyzing the estimation methods commonly applied on-site it becomes evident that these are often affected by human errors that lead to misleading results. The objective of this paper is to identify those errors and discuss a subject which is usually overlooked. As a general conclusion, it was ascertained that most errors derive from inaccurate volumetric data, working procedures and gauging equipment. By acknowledging these widespread practices deep foundations contractors will be in a better position to make informed decisions on how to correct and improve bored pile stability.GENERALBackgroundWhen executing bored piles, the estimation of its concrete overbreak allows a swift appraisal of the excavation stability during the drilling process. This is simply obtained from the proportion of the poured volume of concrete over the drilled shaft theoretical volume, as shown in equation [1].Where CO = concrete overbreak percentage, Vc = volume of poured concrete, Vr = pile’s theoretical volume. This calculation not only provides a general idea of the shaft’s expansion from its theoretical volume, but also the outline of the excavated column’s geometry. For the latter, the outline will be as accurate as the number of measurements taken for each partial known volume of poured concrete. This means that for each load placed inside the excavation there is a corresponding rising of the concrete level. The profile of the definite pile is then plotted (see Fig. 1) and allows inferring about how stable remained the shaft walls up to the moment of casting.The technological developments in this area have provided other methods for determining pile stability before and after pile cast, such as ultrasonic echo sensing, cross-hole sonic logging or thermal integrity profiling systems. Notwithstanding, concrete overbreak assessment remains as common practice and confers the advantage of providing stability information during the process of pile casting."

Jan 1, 2017

By Dimitris Pachakis

In this paper, the authors give a brief overview of the current practice guidelines and tools for the seismic design of sheet pile quay walls, emphasizing how the design guidelines are lacking when the existing structure performance evaluation is required to meet performance-based criteria. Relying on recent experience they explain how the existing practices can be amended to focus more on performance evaluation as opposed to design. An example is given of an old sheet pile quay wall analyzed and evaluated for its performance according the recent performance criteria devised for Californian Marine Oil Terminals.

Jan 1, 2011

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. Keywords: Offshore Wind Turbines, Wind Farms, Foundation, Pile, Gravity Structures

Jan 1, 2005

By M. Cornelius

Drilled shaft construction through caving soils has historically been an uncertain, risky and costly operation. Uncertain, because the zone of caving may or may not be known, risky because the loss of a shaft is disastrous, and costly because the Contractor, who faces these risks, must include large sums of money in his bid for shaft wall stabilization techniques. This case study will discuss the stabilization techniques that are typically used within the United States, and then present new technologies, born in Europe, that are being utilized in the States by Malcolm Drilling Company today.

Jan 1, 1999

By Stefan Larsson, Jan Ekström, Jennie Kock-Larsen, Håkan Garin

"This paper describes the testing procedure (or protocols) for quality control of dry deep mixing columns in a major ground improvement project carried out in Sweden. Quality control was mainly based on column penetration tests performed at different stages in the project and on two occasions after installation. In the paper, the results from the tests are compared with tests on the unimproved clay. As expected, the results show that the correlation between undrained shear strength in the columns and in the unimproved soft soil depends mainly on the in-situ stress. However, the correlation probably depends on when the tests were performed after mixing. When the influence of the in-situ stress was excluded from the analysis, no significant correlation could be identified. This means that the undrained shear strength in the columns and in the unimproved soft can be considered to be uncorrelated when the strengths and the corresponding variability are evaluated with depth from groups of tests.INTRODUCTIONQuality control and quality assessment of deep mixing (QC/QA) constitute a key component in verification of the limit state design. Due to the complex mixing process and varying geological conditions, it is normally not possible to sufficiently assess the strength and deformation properties in advance. In Sweden, the most commonly used QC/QA method for verification of the limit state is the column penetration test (Axelsson and Larsson 2003; Bergman et al. 2013). The method works well but is time-consuming and requires many tests since property variability is normally high. The column penetration test can be used to assess the undrained shear strength Cu,col. However, it is not clear how the strength correlates to the undrained shear strength of the unimproved soil Cu,soil. There are common factors such as the in-situ stress state and the natural water content, which makes a positive correlation probable, i.e. as Cu,soil decreases, Cu,col also decreases and vice versa. The unimproved soil has a natural spatial variability, but it is not known if the improved soil follows the same variation. The mixing process has a substantial influence on the strength variability and may supersede the influence of other factors. However, if a sufficiently good correlation exists between Cu,col and Cu,soil, information from the geotechnical ground investigations can be used in the design and planning of QC/QA of deep mixing in a more stringent manner. Information about the correlation is also essential in reliability based design, where a strong positive correlation may have a negative influence on reliability. However, as discussed by Al-Naqshabandy and Larsson (2013), this correlation may be weak or insignificant for a representative failure domain where the mixing process may have a dominant influence on the strength variability. It is thus of interest to assess the correlation."

Jan 1, 2015

By A. J. Partos

The figures and tables referred to herein are presented in the Proceedings; Volume I, Pages 309 through 316. The 61-story One Liberty Place, at 315 m., is the tallest building 1n Philadelphia and was in 1987 the ninth tallest building in the world. One Liberty Place is supported on drilled piers socketed in heterogeneous metamorphic rock. Design load distribution was 40% on the base and 60% by shaft resistance. Drilled Pier G-10 supporting a T13-A type outrigger column was instrumented. There 1s no uplift load on the exterior outrigger columns. This column supports a 53,850 kN compressive load which includes a 13,440 kN windload. Table 4 presents experimental parameters from straight line interpolation of Mohr failure envelopes for the Wissahickon schist. Lowest values of cohesion (12,200 kN/m2) and angle of internal friction (19°) are at a 50° - 59° angle of foliation. Figure 3 presents a typical pier supported by shaft resistance 1n decomposed (D) and coreable (C) rock and by end bearing (B).

Jan 1, 1991

By Aaron S. Bradshaw, Ryan M. Coulson

The offshore wind industry in the United States is slowly emerging with the recent construction of the first offshore wind farm located off the coast of Rhode Island. The turbines at the Block Island wind farm are supported by piled jacket structures, which historically have been used for much heavier oil and gas platforms. Offshore wind turbines have unique design requirements and the axial behavior of the supporting piles under cyclic loading is important to design. Cyclic degradation along the pile shaft can affect the capacity, deformation, and stiffness performance of the foundation and of the structure as a whole. This paper proposes a strain-based approach to estimate the fatigue (or endurance) limit of a cyclically loaded pile that may be applicable to long-term service loading. The method is applied to an existing load test dataset and the analysis results appear consistent with the observed pile response. INTRODUCTION The demand for renewable energy has been increasing in recent decades and wind power has seen a dramatic increase in popularity. In Europe, as of 2017 there were 4,149 grid-connected offshore wind turbines across 11 countries (windeurope.org), many of which are supported on monopile foundations. It wasn’t until recently (2016) that the first offshore wind farm was constructed in the United States off the coast of Block Island, Rhode Island. The project included 5 piled jacket structures founded in terminal moraine deposits. Future offshore wind development along the U.S. eastern seaboard could possibly utilize jacket structures in granular foundation soils. Loads from wave, wind, and turbine rotation induce cyclic loads on the foundation that have on the order of 108 loading cycles over the service life on the structure (Schneider and Senders 2010). Turbines located along the U.S. east coast have the added risk of hurricanes. As shown in Figure 1a, the lateral loads on a jacket structure are transferred primarily as axial compressive and possibly tensile loads on the supporting piles depending on the weight of the structure. The friction along the shaft of the pile can be prone to cyclic degradation, leading to reduced pile capacity and stiffness, and increased deformations. An offshore wind turbine foundation must be designed for a variety of limit states including ultimate, serviceability, and fatigue limit states. For a jacket structure this would include an analysis of the ultimate axial pile capacity, axial stiffness, and axial deformations, all of which can be affected by cyclic loading both under extreme (i.e. storm) conditions as well as long-term service conditions. Axial pile stiffness is needed, for example, to estimate the natural frequencies of the structure as a whole and to assess dynamic and fatigue loads. The structure must be designed such that its natural frequency remains outside the loading frequencies of the waves and turbine blade passing frequencies to avoid resonance. Therefore, prediction of the axial response of the piles is important to the design of these structures.

Jan 1, 2018

By Michael D. Justason

This paper details the static and Statnamic load testing on a 600 mm square pre-stressed concrete pile. The pile was located at Pier 15 on the 20 million-dollar Bayou Chico Bridge Project in Pensacola, Florida. The pile was 10.5 meters long and had a design load of 1.3 MN. Three static load test cycles were performed in November, 1996. The Statnamic load test was performed in January, 1997. The Davisson Failure load of the first cycle of the static test was 3.7 MN, and the Davisson Failure load of the Statnamic test was 3.2 MN. The load-displacement curves for the two types of tests were very similar, indicating that the Statnamic load test performed well in the sandy soils. Strain gauges embedded in the pile showed 35% skin friction and 65% end bearing for both test methods. Strain gauges were located at equal spacing at five elevations in the pile. A toe accelerometer verified the rigid body assumption of the Unloading Point Method currently used in the analysis of Statnamic load tests. The data collected from the pile instrumentation was of excellent quality and represents some of the best research to date comparing static and Statnamic load tests.

Jan 1, 1997

By M. A. El-Sohby

The paper describes some problems encountered with the foundation of a deep drainage caisson constructed on the Nile Bank in Cairo. The use of suction dredging while sinking the caisson led to a piping failure of the sandy soil in the base which was loosened during the process of pumping. A study was carried out to investigate the problem and a procedure was adopted to retain the stability of the caisson.

Jan 1, 2010

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 L. C. Reese

? Good construction and inspection presumed. ? Capacity-computation factors are independent of construction method. ? To account for variable or uncertain site conditions, anticipated construction problems, and/or minimal inspection, increase factor of safety. ? Conduct load tests and/or develop easily implemented design alternates (e.g., straight shaft in case bell can't be formed) to reduce factor of safety.

Jan 1, 1988

By Zhu Tonghao

A method of calculating anti-slide pile, sheet pile, underground diaphragm and structure with anchors etc. is proposeed in the paper. The effect of the various layers of soil, anchors and bracings etc. on laterally loaded structures may be considered in the model. In the analysis the structure is divided into a series of elements. The transfer matrices of both deformation and internal force are established for each element. According to continuous condition neighbouring element should be connected. Thus the deformation and internal force of each element can be found out in conbination with boundary conditions. The method has a wider adaptability and it can be applicable to a great variety of the analysis of interaction between various structure and soil. If parameters in model are selected properly, the computed results would be in good agreement with the measured data.

Jan 1, 1991

By J. Nakayama

For installation of round steel piles or cast-in-place pile construction through boulder contained ground or rocky formation, usual system does not function properly or impossible to work. This paper introduces an installation system which combines unique mechanism where the drill is installed on the top of a driving round steel pile or a stand pipe which is initially driven into the overburden to the depth of self-standing. When the pile driving or bore hole drilling encounters hard strata or boulder contained ground, hard material shall be crushed by the down-the-hole chiselling operated in adjustable short stroke and high frequency of blows while cuttings are discharged in reverse circulation through central reverse pipe while round steel pile is simultaneously stroked by a hydraulic hammer. The paper shall explain the mechanism of the system and introduces construction examples for bridge foundation and piled jetty.

Jan 1, 1999

By Mark A. Willian

The purpose of this short paper is to present soil profiles and basic soils information for the portion of the I-880 Replacement Project alignment where highway structures are to be built. The information presented here is derived primarily from foundation investigations conducted by the Caltrans Foundation Unit (currently the Structures Foundation Branch, Office of Structural Foundations) and by others under Caltrans direction. The foundation investigation for the I-880 Replacement Project began in May of 1991. The field work was completed in May of 1992 and consisted of 93 rotary sample borings, 11 consolidation sample borings, 6 TEXAM® pressure meter borings, six in-place vane shear borings and 57 electronic cone penetrometer soundings.

Jan 1, 1996