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By Farhad Elmi

In this paper, a new procedure is used to find the bearing capacity of single piles and cone penetration resistance in soils. Although the procedure is mainly applicable to clay and sand using any plasticity model, this paper deals only with steady penetration in Sand. Cylindrical cavity expansion around the probe in a calibration chamber is modeled by finite element method using the HUJEUX elasto-plastic multi-mechanism model. The penetration resistance (qc) is related to cylindrical cavity expansion pressure limit (pL) using the method of Salgado et al. (1997). This procedure is tested using the results found in 3S/IMG calibration chamber. In this article the word "penetrometer" refers to both pile and cone.

Jan 1, 2002

By Andy Boeckmann

Engineers and owners widely recognize the benefits of foundation reuse - cost savings, reduced construction schedules and reduced environmental impacts, among others. Yet for many projects with existing foundations identified as reusable, reuse is an idea that is discussed at length before cold feet prevail. To address this disconnect, Deep Foundations Institute (DFI) formed the Foundation Reuse Task Force in 2021, which intends to promote reuse, leveraging experience among DFI members and collaborating across pertinent committees. Indeed, the task force includes about 40 members drawn from the Subsurface Characterization for Deep Foundations, Sustainability and Testing and Evaluation committees. One of the first orders of business for the task force was to create a database of successful reuse projects, developing short summary documents highlighting the database projects and recruiting reuse-focused presentations for the ITS Money program. Solid progress has been made on each front: the case history database includes 12 cases so far; the first three summary documents were recently published to DFI's website and foundation reuse projects have been well represented among the past year's ITS Money program. The reuse case history summary documents are available at www.dfi.org/foundation-reuse- case-histories; each of the three is also discussed below. The summary documents demonstrate the feasibility and benefits of foundation reuse. The documents are therefore a useful tool for foundation engineers to share with owners, structural engineers and anyone else who may be hesitant to pursue foundation reuse. The task force continues to welcome new members and anyone interested in joining can contact Andy Boeckmann. The task force is also eager to highlight additional reuse success stories. Anyone with case history information to share is also encouraged to contact Boeckmann.

Jul 1, 2022

By Ben C. Gerwick

This publication is intended to document recent innovations and technologies that have the best potential for effectively improving the quality of marine foundations while reducing the cost, time and risk of construction. Marine foundations originated in Neolithic times with the Swiss Lake Dwellers who constructed pile-supported houses, safe from invading tribes. The Queen of Babylonia built the first recorded bridge in 1500 BC across the Tigris. The foundations were large flat stones laid on the river bottom. About the same time in India, builders extended their water well techniques to the construction of ?well? foundations in the beds of their rivers. These were really the first open caissons; brick walls were built up in a circular ring while divers excavated sand from the bottom, sometimes at a depth of 100 feet. The Romans extended the clay-filled cribs of the Middle East to shallow cofferdams, which they sealed by underwater concrete made with pozzolanic cement from Mt. Vesuvius.

Jan 1, 2013

By Richard Berry

The spacing of grout injections is typically about 2 to 2 V½ meters if the purpose of the grouting is densification of the in-situ soils. Hole spacing will vary with the in-situ soil properties and the grout injection rate; faster rates requiring closer hole spacing.

Feb 10, 2003

By Jim Bruce

This paper presents details of a slope stabilization scheme built in late 2003 at a 16m-high railway embankment in southern Ontario, Canada. The owner, faced with continuing maintenance and safety issues arising from numerous nuisance slides, and residential neighbors in close proximity to the slope, sought new proposals to replace a previous recommendation to cut down all trees and undertake a deep soil nailing scheme. A non-reticulated micropile array with surface cap beam was proposed and built on the south side of the embankment with no tree removal required. A detailed FLAC analysis was completed, using multiple iterations to arrive at the eventual, optimized micropile depth and spacing. Analysis predicted an 18% increase in the factor of safety. Short term inclinometer monitoring and performance evaluations in the months since construction so far corroborate the prediction.

Jan 1, 2004

By Mark Spence, Tom Lardner, Matthew Janes

"IntroductionThe design-build method streamlines project delivery through a single contract between the Contract manager and the design-build team. The design-build method places emphasis on collaborative project management between design and construction disciplines to minimize project schedule, reduce costs, encourage balance risk amongst the design-build team. Since 1985, the percentage of nonresidential design and construction projects has increased from 5% to 45%.1A project carried out in Edmonton, Alberta, Canada will be used as an example to illustrate the challenges of the design-build project delivery method and the merits of establishing a GBR. The project involved a complex slope stabilization as part of an extensive freeway widening. At the project location the roadway was being widened within the base of a historic stream valley into a steep slope with a history of a previous slope failure. The slope was to be steepened through the installation of a series of 14 interlocking arc structures constructed half way up the slope. Access and schedule proved critical to the successful completion of the project.Geotechnique and Site HistoryThe geotechnical investigation undertaken for the site included six boreholes drilled at the crest of the slope to depths ranging from 14.5 m to 30.2 m. Laboratory testing of the soil samples included direct shear tests, Atterberg limits and grain size analysis. The geotechnical report also referenced a previous geotechnical investigation that was carried out in response to a failure of the slope in 1971."

Jan 1, 2015

By George M. Filz

Restrained basement walls and unrestrained but massive concrete walls on rock foundations experience very small movements in response to lateral earth pressures. Such walls are often designed using at-rest earth pressures without consideration of either compaction-induced lateral pressures or vertical shear forces resulting from compression of the backfill in response to self-weight. Compaction-induced lateral earth pressures can be detrimental to the integrity and stability of retaining walls. For example, the lock walls at Eisenhower and Snell Locks on the Saint Lawrence Seaway near Massena, New York, were damaged by compaction-induced lateral earth pressures, and an extensive rehabilitation program was necessary to ensure safety of the locks. Vertical shear forces, on the other hand, can be beneficial to stability because the downwards-directed vertical force tends to counteract the overturning moment from lateral earth pressures. The contribution of vertical shear forces is not included in most modern analyses of non-moving walls, but Terzaghi used this effect in his design of a high concrete retaining wall at Fifteen Mile Falls Dam. The lock walls at Eibach Lock on the Main-Donau Canal in Germany were instrumented for both lateral and vertical stresses applied by the backfill to the wall, and the resulting measurements show that vertical shear forces from the backfill were significant and persistent over the multi-year period that the wall was monitored. Other data from pilot-scale retaining walls confirm the existence of both compaction-induced lateral earth pressures and vertical shear forces. These forces should be considered in design of non-moving walls.

Jan 1, 2003

By Paul Summers, Kevin Richardson, Willem (Billy) Villet, Paul J. Sabatini, Edward C. Clukey

"Between 2008 and 2009, more than 6,000, 23-m long deep mixing method (DMM) elements were constructed to support 124 concrete mats comprising the foundations for the process trains for an LNG facility. The Owner requested first-of-its-kind analyses and assessments to confirm the quality and reliability of the DMM foundation. This paper provides information on these assessments and the procedures used to ultimately conclude that a fit-for-purpose foundation system was constructed.During early phases of construction, several DMM test cores revealed nodules of unmixed clay in upper core samples. A comprehensive review of available DMM core information was undertaken. It was concluded that the amount of coring being conducted as part of the contractor’s QA/QC program should be increased to achieve a foundation system with the required level of reliability.Three-dimensional finite element analyses were completed considering various distributions of defects in the DMM elements and the effects of potential downdrag on DMM elements. Calculated mat settlements and mat stresses were compared to cases without defects in the DMM elements. Various distributions of loaded and unloaded mat areas and number and position (both in the subsurface and laterally) of defects were considered. Four (of the 124) mats were identified as potentially “at-risk”. The settlement performance of these mats is currently being monitored and, to date, performance has been acceptable.IntroductionThe foundation support system for the process train at a major LNG facility comprises more than 6,000, 23-m long DMM elements. The general subsurface stratigraphy at the project site comprises (from the ground surface): (i) up to 8 m of fill sand initially placed underwater building to a stable construction platform; (ii) up to 12 m of soft organic clay (Unit II clay); and (iii) clayey sand and sand layers becoming progressively denser with depth (Unit III sands). Each DMM element comprised two secant 1.5-m diameter DMM columns. DMM elements were typically arranged as cells enclosing one, two, or three DMM elements."

Jan 1, 2017

By E. Ulrich Klotz

It is difficult to predict accurately the capacity of driven piles in sand. In practice, this uncer­tainty either leads to conservative designs if the capacity is under-predicted, or worse, if the capacity is over-predicted, it can lead to severe foundation problems. One significant possible cause of the problem is that currently available semi-empirical design methods do not capture the fundamental mechanisms that govern the load capacity of driven piles in sands. As part of a recent research project at City University centrifuge tests on a driven model pile in sands have been undertaken. A fully instrumented model pile was constructed and pushed into samples of quartz and carbonate sand thus covering a wide range of mineralogies. Tri-axial tests were used to determine the fundamental patterns of behavior of the sands. This allowed a general framework to be established, in which the in situ stress:volume relationship is shown to govern the capacity of the pile. The paper sets out with a brief introduction of the experimental techniques used in the study. The results of the pile tests are discussed in detail with particular attention given to distribution of the radial stresses along the pile shaft. Existing design methods for piles in sand are then discussed in the light of the new understanding gained from the research, highlighting their deficiencies and suggesting an improved approach.

Jan 1, 2002

By Frank Rausche

The more widespread use of Augered Cast-in-Place (ACIP) Piles has generated increased demand for improved quality control measures. These deep foundation elements are often relatively long and slender and their structural quality depends on the experience of the installers, the adequacy of their drilling and pumping equipment, and of course, the properties of the soil. Since the concrete of ACIP piles is pumped under pressure into the borehole, the piles may achieve a very high unit shaft resistance if conditions are favorable and the piles are well constructed. Three types of methods can help assure that the piles are properly executed. During construction, monitoring the volume of concrete pumped and the pressure applied helps avoid structural defects. After installation, and once the concrete has hardened, the Pulse Echo Method allows for a check of the structural integrity of the shaft. Finally, a load test, performed some time after installation, yields a check of both bearing capacity and structural integrity of an individual pile. Because of their expense and associated construction delays, static load tests are normally done for only a few piles. However, at large construction sites, it may be necessary to perform many load tests either as a planned construction control activity or as a means of spot checking or verifying suspect piles. For smaller sites, however, static load testing may be prohibitively expensive. In such situations, dynamic load testing, originally developed for driven piles, has frequently been employed for drilled shafts and ACIP piles. In the latter case special consideration must be given to the ACIP pile slenderness and their often relatively low concrete design strength, which may not tolerate high dynamic loading stresses even though their unit resistance along the shaft is relatively high. Lately, the dynamic load test has become more feasible with the availability of loading systems that are custom tailored to this particular pile type. These systems produce a low velocity, low stress and high energy impact. Recent developments have also made the instrumentation process simpler: force measurements are now made on the ram rather than on the pile for increased reliability and simplicity. This presentation describes the requirements for successful dynamic load testing of auger cast piles and summarizes results from several projects where the new loading system and newly developed instrumentation was employed. A few cases are presented correlating static load test results with dynamic predictions, calculated by CAPWAP®.

Jan 1, 2001

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."

Jan 1, 2007

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 Karen Dawson

This paper presents a case study of the deformation-based design, construction, and performance of stone column ground improvement (GI) beneath a mechanically stabilized earth (MSE) wall and bridge abutment with heights up to 50 feet. As part of the widening of Interstate 5 (I-5) to allow High Occupancy Vehicle (HOV) lanes in Tacoma, Washington, a new approach and span over the Puyallup River will be constructed. During the soils investigation and design phase of the project, low plasticity silts (ML) inter- bedded with silty sand layers and organic silt where identified as being potentially liquefiable. Stone column ground improvement was designed using a deformation-based approach to address static settlement and seismic stability of the proposed MSE embankments. The deformation-based design of the stone columns resulted in significant savings over a limit equilibrium-based approach. This paper presents the results of sonic coring taken from the initial stone columns installed and compares these results to the real-time data acquisition reports from the stone column installations. Vibration monitoring results during stone column installation are included. Settlement monitoring at the face of the MSE wall and buried vibrating wire settlement monitoring elements are presented and compared to the original settlement predictions.

By Douglas Heenan

The fracture orientations were inferred based on theory and previous experience. The fracture pattern was not monitored during the project. Grout volume was recorded at each sleeve port and real time movement monitoring of the building foundation was performed.

Feb 10, 2003

By Saba Mohan

This study presents results based on the Pile Installation Demonstration Project (PIDP) that was conducted as a part of the East Span San Francisco-Oakland Bay Bridge Seismic Safety Project. For the three full-scale pile installations, two different high-energy hydraulic hammers were selected for the installation. However, these hammers may not have sufficient energy to drive these large diameter piles at their ultimate capacity following long-term set-up. Nevertheless, these hammers were selected because, soil plug behavior, the generation of excess pore pressures and remolding of soil during driving were expected to reduce the shaft and end bearing resistance, and therefore reduce the energy required to drive these piles to design penetration. Data collected during continuous installation driving and after a series of re-strikes at different set-up times ranging from 1 to 33 days were used as input data for CAPWAP. These results were used to estimate the soil resistance along the pile length and at the toe of the pile, and the soil pile set-up behavior. Validity of the procedures used to predict the soil resistance to driving and predicted blow counts were verified with the field observed blow counts and the energy that was delivered to the pile. Based on combined CAPWAP analyses, the soil pile set-up with time was estimated and compared with results of other methods currently available in the literature for predicting the soil pile set-up rate.

Jan 1, 2002

By Saba Mohan

For the three full-scale pile installations, two different high-energy hydraulic hammers were selected for the installation. However, these hammers may not have sufficient energy to drive these large diameter piles at their ultimate capacity following long-term set-up. Nevertheless, these hammers were selected because, soil plug behavior, the generation of excess pore pressures and remolding of soil during driving were expected to reduce the shaft and end bearing resistance, and therefore reduce the energy required to drive these piles to design penetration. Data collected during continuous installation driving and after a series of re-strikes at different set-up times ranging from 1 to 33 days were used as input data for CAPWAP analyses. These results were used to estimate the soil resistance along the pile length and at the toe of the pile, and the soil pile set-up behavior. Validity of the procedures used to predict the soil resistance to driving and predicted blow counts were verified with the field observed blow counts and the energy that was delivered to the pile. Based on combined CAPWAP analyses, the soil pile set-up with time was predicted.

Jan 1, 2002

By Matthew Janes

The installation of piles and casings is becoming increasingly difficult as restrictions on vibration become common in major urban areas. The use of high frequency, resonant excitation of a pile or casing permits ease of installation of sections to great depths with near imperceptible vibrations as close as 1 pile diameter. The new Resonant Driver is able to excite a pile at its resonant frequency (up to 150 Hz or 9000 VPM) to produce elevated levels of acceleration, force and displacement in the pile. The combination of extremely high acceleration and controlled levels of displacement allow the pile to slice through varied soil with almost no vibration translated into the ground. In direct comparisons between conventional vibrators and impact hammers the Resonant Driver produces less than 1/50th the vibration. The Resonant Driver results in ground vibration of between 1/20 and 1/40 of common limit levels (1 cm/s or 0.5 in/sec) as close as 1 pile diameter. At a distance of 5 m (16 ft) from the pile or casing vibration levels approach imperceptible levels. The Resonant Driver uses a proprietary algorithm to tune the drive vibration to the changing natural frequency of the pile as it is driven into the ground. By maintaining resonance the energy in the pile is built up like in a flywheel on an engine or a child on a swing. This build up of energy aids in driving and significantly reduces waste. Recent experience using the Resonant Driver is proving the technology can drive a variety of steel pile and casing sections through varied soils. Continued use of the Resonant Driver will create a data base of various pile and casing sections, soil types and achieved capacities.

Jan 1, 2008

By Brian W. Wilson

A case study is presented that describes the design and implementation of a combined blast densification and deep dynamic compaction program which was undertaken to improve the foundation soils for a proposed tailings dam raise in Ontario, Canada. Based on the results of the geotechnical investigation it was determined that the foundation of the dam would be situated on tailings of both variable thickness and density, much of which would be susceptible to liquefaction under the design earthquake for the region and type of facility. Blast densification trials were completed by the owner and the results of these made available to prospective tenderers in response to a call for a fixed price contract for the design and implementation of a densification program for approximately 800,000 m3 of foundation tailings. The variation in tailings gradation and the impacts of such on the ground improvement program are discussed, as are details of both the additional blast densification field trials completed by the contractor, and the selected blast pattern and explosive charging used for production blasting. The applicability of the various ground improvement techniques to the actual conditions encountered, and the results obtained are also discussed.

Jan 1, 2010

By K. J. Yang

Based on investigations and model tests combined with pile foundation on Code compilation of drydocks, we present this report to give informations against uplift pressure of piles beneath floor of drydock. In a same kind of soil, we have got comparative tests results with single pile and pile group, and the latter was performed at different spacings, different embedded depths and different number of piles in the group. Having analyzed through the results, there are some new understandings of regularity about failure mechanism and uplifting capacity of single pile and pile group, as well as optimum embedded depth of pile foundation. The results of research approach to measured values of full-scale and model tests at home and abroad, it has been placed into the Design Code of Drydock in China (1985), and can give a reference to design of pile foundation at sea and on land under uplift loading.

Jan 1, 2010

By Giovanni Lombardi

In order to get a clear overview of the grouting works carried out, to avoid misinterpretations of the data and functions shown on the display of the grout monitoring device, it is recommended to keep the flow rate as constant as possible. Obviously, at the beginning of the process, the flow rate will increase from nil to the selected "basic" value. An important question frequently addressed is also how to reduce the flow rate in nearing the GIN limit so to finally reach the target intensity. Depending on the actual conditions, there are different manners to proceed. However, the following one appears to be the most convenient. It is represented on Figure 25. Being GIN the target intensity, two new limits at, let's say, 0.95 GIN and at 1.05 GIN as shown in the figure should be defined. The selected basic grout flow rate "q0", is kept as constant as possible all along the grouting process until the 0.95 GIN limit is reached. The flow is then reduced step wise to 2/3 q0, 1/3 q0 and zero at crossing each of the three limits. A similar rule can be used in respect to the maximum pressure, while for the maximum volume the process can be stopped at one time. Obviously the number of successive limits and thus the number of steps in reducing the pressure, as well as the width of the fringes defined in said way may be adapted to the local conditions.

Feb 10, 2003