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By Dennis Nottingham

The need for deep compaction of submerged granular soils has led to improvements in this area. 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.

Jan 1, 2013

By Joshua R. Omer

A numerical model is developed for predicting the load transfer and settlement behaviour of vertically loaded, bored cast in-situ piles. Based on analysis of full-scale pile tests, closed-form equations are formulated to uncouple the shaft and base transfer resistance components of the pile/soil system. Appropriate parameters are introduced to take into account: (i) the shaft resistance distribution in unlined and partially lined piles, (ii) the effects of ?soft toe? (voided toe pile) behaviour on base resistance development. For convenience, an interactive computer program has been developed in Matlab? with a user friendly interface system. The program can be applied to predict the complete load-settlement curve and axial force distribution in bored cast in-situ piles if reliable soil test data are available. To demonstrate its validity, the proposed method is applied to 4 test piles, which are also analysed using two previously published methods: (a) elastic solution method and (b) layer discretisation method. Methods (a) and (b) above are based on load transfer (t-z) and finite element models respectively. It is shown that the proposed method yields axial force distributions and load-settlement curves that are in good agreement with the observed pile test data.

Jan 1, 2010

By Jerold Bishop

The application of the ?electro-hydrodynamic effect? (EHDE) to civil engineering has been made in the construction of drilled piles. Equipment for the commercial application of this process was developed in Russia in the late 1980's. The process is approved for general use by the Russian Federation building code and numerous projects have been successfully completed with this technique. EHDE is a process by which a moderately powerful shockwave is released in the bottom of a drill hole filled wet concrete slurry. The energy is carried outward through the fluid with minimal loss because it is an incompressible medium. Repetitive discharges provides a series of energy pulses which will compact the soil along the pile shaft and at base of the pile. The process is analogous to repeated applications of low energy blast densification or to dynamic compaction. In general, the process is not depth dependent. Repeated application of this treatment in a drilled pile hole can increase soil density at the base and along the shaft of the pile, as desired. The overall result is that the geotechnical capacity can be improved significantly. Test results documenting improvements are presented and other applications considered.

Jan 1, 2007

By Matthew E. Meyer

Renovation, rehabilitation, restoration and expansion of existing residential, retail, commercial, hospital facilities and historic structures requires assessment and evaluation of foundation systems of various ages. The concept of demolition and reconstruction in urban areas is often more challenging, costly, and even prohibitive in some cases due to historic regulations. The authors have been involved with numerous projects related to existing foundation assessment and retrofit, including: hotel and hospital expansions, historic Art-Deco hotel renovations and expansions, garage structure expansions, additions to prominent auction houses, casinos, printing facilities; high-rise structure foundation retrofitting; and forensic evaluations of existing building and highway structure foundation systems, and marine bulkhead sheeting systems. The use of non-destructive testing techniques, high-strain dynamic load testing, full scale pile cap load testing and 3-D laser scanning technology has proved to be vital in the assessment and evaluation process, as well as design of foundation retrofit alternatives. This paper presents various methods and techniques to facilitate a phased approach for re-use of foundation systems. These methods and techniques are illustrated through the author?s experience and selected case histories from projects with varied foundation and geologic conditions.

Jan 1, 2009

By Dan Brown

This paper provides an overview of the advantages and limitations of continuous flight auger (CFA) and drilled displacement (DD) systems compared to other deep foundation systems, along with a summary of important considerations for selection and design. Geotechnical and project considerations are described which favor the use of CFA and DD piling, and also which may be problematic for this type of construction or which may limit the practicality and competitive advantages. A brief summary of design methods for axial and lateral loading is included.

Jan 1, 2005

By Gianfranco Di Cicco

Seepage problems were recorded for more then 40 years at the Walter F. George lock and dam. In 2001 the Mobile district of The U.S. Army Corps of Engineers turned to the installation of a 200 feet deep cut-off in a final attempt to remedy the situation. The advertised design-built contract requested the installation of the cutoff wall in front of the concrete structure of the dam starting from 90 feet of water, cutting through a concrete lock structure, a submerged retaining wall and extending on both sides on the earthen embankments. This paper summarize the history of the project and the installation of the first recorded cut-off wall constructed under deep water, upstream to an existing dam structures and under an existing concrete lock. The technology used combined with the project's results may be considered a milestone in the marine foundation and the marine cut-off wall construction technology.

Jan 1, 2013

By Jennifer Peirce Brandt

Project documents and the United States Army Corps of Engineers? permit for construction of the Stemmers Run Relief Wastewater Force Main across the Back River in Baltimore County, Maryland specified a minimal width, steel sheet pile cofferdam and a 12 feet wide, pile supported, timber decked, causeway trestle ? both approximately 1700 feet in length. Due to the impractical width of the causeway, the contractor desired to combine the cofferdam and the causeway structures in order to minimize wetland disturbance and maximize access for construction equipment. The resulting support structure was a steel sheet pile cofferdam, approximately 17 feet wide, internally braced, and capped with transverse timber deck mats to serve as the access and work trestle for the trench excavation, pipe bent construction, and trench backfill. Construction of this cofferdam/causeway progressed from the north shoreline toward the middle of the river. Then, working back toward the north shoreline, the contractor excavated, installed the 54 inch diameter pipe and H-pile support bents, and backfilled the trench in increments of approximately 60 linear feet. Excavation spoils from one section were used to backfill the preceding section. As the pipe installation progressed toward the north shore, the steel sheet piling and timber deck were removed. As sufficient sheet piling and deck mats were removed, the contractor began the process anew from the opposite shoreline using the reclaimed materials. The project was complicated by the presence of deep, very soft, weight of hammer, silts and organic clays and an unbalanced, hydrostatic head of 20.5 feet. In addition, concurrent pile driving, excavating, and backfilling in successive cofferdam sections required the use of heavy, long reach, hydraulic backhoes, and a 200 ton capacity crawler crane which controlled the design of the timber causeway deck and its supporting sheet piles.

Jan 1, 2008

By Fred Tarquinio, Giovanni Bonita, Lars Wagner

"A new embassy for the Peoples Republic of China is under construction in Washington, DC. The 475,000 square feet (44,125 m2) structure has five levels below ground and four above, making it the largest embassy in Washington DC. A vertical soil nail wall was used as the primary support of excavation system for the project. The soil nail wall was irregularly shaped, benched in areas, and up to 98 feet (29.9 m) in height. The soil nail and shotcrete system consisted of approximately 1,600 soil nails and 50,000 square feet (4,645 m2) of exposed shotcrete wall surface. Design and construction challenges included soft soil conditions, inside wall corners, underground utilities, seismic impacts from blasting, and logistical and political factors. Overall, wall movements were lower than expected, with maximum horizontal movement less than 0.25% of the total height of the excavation.INTRODUCTIONThe proposed Embassy of the Peoples Republic of China in Washington, DC, will consist of about 475,000 ft2 (44,125 m2) of building space and contain up to four fl oor levels above ground and fi ve levels of basement (Figure 1). When completed, the building will be the largest embassy in Washington, DC. The architect for the project, Pei Partnership Architects, along with the world-renowned architect I.M. Pei, made effi cient use of the site by inserting the building into the existing slope. Consequently, excavations reach heights up to 98 feet (29.9 m) on the southern side of the property and 42 feet (12.8 m) on the northern side.The soil nail and shotcrete system consisted of approximately 1,600 soil nails and 50,000 square feet (4,645 m2) of exposed shotcrete wall surface. The location of the building relative to the property line called for tight excavation requirements, including precise wall positions and shotcrete tolerances. Design and construction challenges included soft soil conditions, inside wall corners, arched walls, underground utilities, seismic impacts from blasting, and logistical and political factors.SITE INVESTIGATIONInformation obtained from the geotechnical investigation revealed about 10 to 20 feet (3.1 to 6.1 m) of a loose to medium dense fi ll material placed during previous site activities. The fi ll material was underlain by a silty sand and sandy silt residual soil derived from the natural weathering of the underlying bedrock. This soil sequenced naturally from a medium dense to very dense material through natural weathering of the underlying bedrock. This soil sequenced naturally from a medium dense to very dense material through natural weathering processes in the rock. The underlying bedrock was locally characterized as a gneiss. A water table elevation about 17 feet (5.2 m) above the fi nal excavation level was revealed, except in the “radius” area, where a leaking water main/hydrant generated a high local water table."

Jan 1, 2007

By K. Ronald Chapman, Claus Ludwig, Doug Jenevein

"In the spring of 2005 Schnabel Foundation Company completed a $15.2 million Design/Build subcontract to underpin 11 structures, and provide 202,800 square feet of earth retention for the Reno Transportation Rail Access Corridor (ReTRAC) project in Reno, Nevada. Schnabel’s work was part of a Design/Build contract to depress a railroad alignment through downtown Reno. The depressed section was 2.2 miles long, 54 ft wide, and up to 35 ft deep (3.5 km long, 16.5m wide and up to 10.7m deep). The trench structure was required to be watertight. SUBCONTRACT WORK OVERVIEWEleven buildings along the track alignment required underpinning. Three types of underpinning were used, designated Type 1, Type 2 and Type 3.At four buildings the trench retaining walls were to be located directly under the exterior footings. This alignment eliminated traditional underpinning and cut-off wall techniques that could normally be used to support structures. Type 1 underpinning was used at these buildings. This underpinning system consisted of a combination of permeation grouting, hand-dug piers, and permanent tiebacks. This underpinning system became the new watertight trench walls.Five buildings were located a few feet behind the trench walls, and their exterior walls were supported by continuous footings. Type 2 micropile/pile cap underpinning (patent pending) was used to support these buildings.The remaining two buildings were also located a few feet behind the trench walls, but they had column footings along the exterior walls. At these structures traditional micropile underpinning was provided through the existing footings. This is described as Type 3 underpinning.Temporary earth retention was required on both sides of the trench along most of the alignment. This shoring supported frontage roads, private property and surcharge from the temporary railroad shoofly running parallel to one side of the trench.SUBSURFACE CONDITIONSThe soil along the trench alignment consisted of river outwash deposits. The top 2 to 18 feet (0.6m to 5.5m) generally consisted of flood plain silt and sand deposits, or fine-grained fills. These fine-grained soils are underlain by the Tahoe Outwash Formation which consists of interbedded layers of sand; sand and gravel; and sand, gravel, cobbles and boulders. Some of these layers encountered during construction consisted of 30 to 50 percent cobbles and boulders, with some boulders up to eight feet in diameter.A major challenge to the design and construction of the trench structures and the underpinning was the ground water table which was 10 feet (3m) above subgrade in the deepest portions of the trench. Based on specification restrictions, temporary and permanent dewatering was not feasible. As a result, the selected design and construction methods had to consider three water conditions: the anticipated groundwater level during construction (CGW), the groundwater level for permanent design (DGW), and an additional special design condition with water at street grade."

Jan 1, 2006

By George Machan

Bitumen coatings have been successfully used to significantly reduce downdrag on piles. Thicker coatings of "soft" bitumens can accommodate downdrag so well that very little downdrag load is transferred to the pile. Many of the case histories describe better than 80 percent downdrag load reduction. Bitumen coatings have been used on several projects in Oregon. On the Mocks Bottom Bridge project (see Reference 1), experimentation and instrumentation confirmed the viability of bitumen coatings and provided insights for design and construction. Subsequent bridge projects have used this information and have raised issues to be resolved.

Jan 1, 1989

By Lucian Bogdan

On many occasions during construction and service life of the structure, it is crucial to know the load in post tensioning tendons and anchors. Although there are many methods to measure the tendon force, most of them are cumbersome, expensive and the accuracy differs depending on the method used Dyna Force sensor uses the Elasto-magnetic technology (EM) and non destructive testing (NDT) to direct measure stress level in prestressed strands or bars installed on ground anchors or post tensioning tendons. Dyna Force sensor can be used to rapidly read the change in load during proof and performance tests and compare with the pressure gauge and during the life on the anchor to monitor existing lock-off load. It can be used also to determine the load along the bonded length of the anchor allowing the contractor to increase or decrease this length. The paper presents Dyna Force operating principle and some applications. In conclusion, the Elasto magnetic technology applied through Dyna Force is a new and easy to use approach to monitor anchor load during proof test and service life of the structure.

Jan 1, 2009

By Jack Hayes

The design and construction of deep foundations involve many uncertainties. For the designer there are uncertainties regarding soil and ground water variability, regarding sampling and lab testing, regarding analytical techniques and regarding construction technique. The latter being the uncertainty over which the engineer has least control and which may have the greatest impact on capacity. Foundations with a high design factor of uncertainty can be very costly. Foundations designed with a high factor of uncertainty may have a low factor of safety, which can be even more costly.

Jan 1, 2000

By Garland Likins

High strain PDA testing has become common for verification of capacity of both driven and bored piles. It is equally applicable to Augered-Cast-in-Place (ACIP) Piles. It also evaluates other aspects of the installation such as integrity. The benefit of high strain dynamic test results for the relatively low cost of the tests compared to conventional static testing has resulted in widespread use. The method is described and specific procedures for testing ACIP piles are outlined. Example results demonstrate the application.

Jan 1, 2000

By David Miller

"The biggest concern about using soil mixing is the inability to observe physically the final product, which has led to a lack of confidence about what is in the ground. After all, you can’t see it and you can’t taste it and you can’t smell it, so are you sure it’s soil mixing? In addition, there are variations in techniques, tools and monitoring that have led to additional skepticism and the desire to “elevate” the product. This skepticism is why the industry is so scrutinized even when there are other technologies being used that do not experience nearly the same level of scrutiny. With other techniques, even with a slurry wall, you can see the backfill before it goes into the ground, and drilled piers have careful evaluation of the concrete mix even before placement into and verification of the open hole. Essentially, you get control over the final material. There is less control in soil mixing, and it’s very dependent on in-situ conditions. These factors make it difficult to rely solely upon installation parameters, quality control (QC) and verification tests. At some point, you may need to apply some engineering judgment.Start at the BeginningThe availability of sufficient and accurate geotechnical data (soil type, heterogeneity, shear strength parameters, variability, etc.) is important in establishing the material that will be drilled. This data will also help in determining the proper mix design to achieve the desired soil cement properties. Many factors must be considered when designing the mix and the mixing program, including any debris in the ground, different soil properties and varying moisture contents.Each of the various factors affect the final properties of the soil cement, so it really takes careful planning and evaluation of the mix design through iterations by looking at the soil types and adjusting the mixes. Clay is going to behave very differently than sand in both mixing efficiency and final properties. That is, the presence of clays results in more difficulty in achieving higher strengths and to physically mix the soil and the binder, whereas the presence of sands results in more difficulty controlling the final permeability."

Jan 1, 2017

By Frank Rausche

Why testing What tests can be done Dynamic load testing Loading device Measurements Analysis Examples

Jan 1, 2001

By Todd Nottingham

Channel deepening of major ports is challenging designers to explore innovative solutions to ensure stability of bulkheads, such as for the Oakland Inner Harbor. This particular challenge was met with the use of the SPIN FIN® Tension Pile for restraint of an HZ combination wall along the Oakland Inner Harbor Shoreline in Oakland, California. A SPIN FIN pile is a pipe pile with welded plates at the pile tip that increase pile capacity. A brief history of the project will be provided as well as results of pile load tension tests, pile strain gauge, and wall deflection under construction loads. Tension pile load deflection results will be discussed with recommendations toward establishing deflection-based ultimate load criteria. A discussion of predicted wall loads and field observed wall loads will be provided.

Jan 1, 2008

By Lok M. Sharma

Development of brownfields is of great interest in these days. Such fields are not easily adaptable for foundations of structures. The uncertainties in ground behavior present challenges of unpredictable subsidence that could be detrimental to the build up facility. A desalination plant had to be located along the seashore, close to the needy population and the existing water supply infrastructure. The available site had been developed as a recreational park area over a dumped construction demolition debris landfill along the coastline. To construct a desalination plant comprised primarily of large concrete basin tanks on slab, founded on the debris fill had its challenges. A ground improvement system in the form of vibro replacement stone columns was designed and constructed. Approximately 5,000 stone columns were installed across the site. This paper describes the analysis process, the design, field load testing, and installation of stone columns. Difficulties during construction and monitoring aspects are briefly described. The plant started operations in the summer of 2008 and to date has performed satisfactorily. When properly designed, the development of brownfields is achievable at other sites.

Jan 1, 2009

By C. O. Riggs

Geotechnical exploration in North America, in particular, exploration for deep foundations analyses, is currently and generally performed following the most basic sampling and insitu testing methods and techniques. Some would surely say that the state-of-practice severely lags the state-of-the-art. Probably more than 90% of all deep foundations, both driven piles and drilled piers, installed in North America are initially analyzed and designed, i. e. geotechnically, on the basis of either the soil penetration resistance obtained by performing the "Standard Penetration Test" (SPT), or from laboratory shear tests performed on samples obtained using 76-mm (3-in.) nominal diameter, thin wall, "Shelby tube" samplers. The use of design data obtained with other exploration methods and devices, such as bore hole pressure meters, flat plate dilatometers, even cone penetrometers, occur on the fringes of practice and often in conjunction with the use of the two simpler methods of analysis. This basic approach probably represents an attempt of the profession to use, as much as possible, common, easily understood and easily communicated procedures in all geologic environments. The characteristics of drill rigs with the required drilling and samplng tools vary somewhat from region to region in North America according to the physiography of the area of use, the types of exploration data required on a day-to-day basis, the philosophy of the engineers and geologists that use the exploration data and the financial resources of the drill rig owner. The physical capability of the exploration drill rig used on a project can have a significant effect on the quality of samples or insitu tests. The physical configuration and the quality of the drill and the drilling, sampling and testing tools not only provide the mechanical capability to obtain data but affect the attitude of the field exploration crew and the quality of work. This complete presentation is taken, for the most part, from a book in preparation for publication: "Geotechnical Exploration and Site Characterization" by C. Riggs, A. Hatheway and N. Schmidt. The book is scheduled for completion during 1987.

Jan 1, 2010

By Pierre Gouvin

This paper describes the design, installation and monitoring of a state of the art real time geotechnical/structural instrumentation monitoring system to facilitate tunnel construction under Interstate route I-5 in Seattle, Washington, USA. The project involved removal of existing highway foundation substructures on both North and Southbound lanes as well as the underground reversible high occupancy vehicle lanes. The system utilized state of the art 3-D pulsed laser scanning, wireless sensor networks, automated robotic total stations, tilt beam sensors, narrow angle tiltmeters, and in-place inclinometers. Dedicated real time data loggers, with a web based graphical interface, provided 24/7 access to critical measurements. In addition to the instrumented sections of wall and roadway subsurface which monitored physical measurements at known points, the pulsed laser scanning allowed complete site monitoring coverage where physical sensors were not located. This data allowed post processing at any location enabling the contractor and designer to respond to unforeseen structural responses to construction. Use of the instrumentation system resulted in the early detection of wall movement, and provided feedback to the designers to facilitate construction process changes in order to minimize further movement.

Jan 1, 2010

By Michael Moran

Typical ACIP Pile Rig [ ] Hollow Stem Auger ? Continuous flight auger ? 3 inch inside diameter pipe ? Auger diameters: 12, 14, 16, 18, 20, 22, 24, 30, and 36 inches ? Auger section lengths: 4, 5, 10, and 20 ft ? Weight ranges from about 70 lbs per ft for 12 inch to 120 lbs per ft for 24 inch and 200 lbs per ft for 36 inch

Jan 1, 2005