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By Jorj O. Osterberg

This paper is for presentation at the 14th Annual Members Conference of the Deep Foundations Institute held at the Hyatt Regency Hotel, Baltimore Maryland on October 10, 1989. This is an introductory presentation of a one hour symposium on the applications of a new testing device. This paper discusses how the device works and its uses. Papers following this describe: - How the cell is constructed and calibrated - Two projects on which the device was used on long driven piles to determine the frictional capacity - A bridge project on which the device was used on an instrumented test drilled shaft and a working drilled shaft

Jan 1, 1989

By Wang Mingshu

The pile foundation is a kind of advanced foundations in the filled or soft soil. In this paper, through the actural engineering of coal dressing plant of Western Opencast Coal in Fushun built on the mining dump with large diameter pile foundation, the construction method and mechanics analysis of pile are given. Unless it is in following stadge, the stability of pile cannot be lost due to its small rigidity. The analysis shows that pile foundations of large diameter ellipse section can decreased hotizontal displacement to 60% ?70% of that of equal section an in the design of a single pile and a single column, the ellipse pile and manual dig hole are most favourable. So a large amount of concrete can be saved.

Jan 1, 1991

By Anand J. Puppala

This paper provides information on various evaluation studies conducted to assess the CPT based interpretation methods. Salient findings from these evaluations are summarized. Additionally, a comprehensive evaluation study on both LCPC and European methods was performed on twenty-four driven piles selected from four different states. This evaluation showed that the LCPC method predictions are close to measured pile capacities. The European method provided good predictions for driven steel piles. Overall, both methods' predictions show high values of coefficients of variations, which are in agreement with other studies. Overestimation of driven concrete pile capacities is attributed to large estimations of unit point resistance. Suggestions to consider appropriate CPT based pile capacity interpretation methods are presented.

Jan 1, 2002

By Anne Lemnitzer

Full-Scale cyclic field testing was performed on a 3x3 pile group consisting of nine cast-in-drilled-hole (CIDH) reinforced concrete shafts and a comparable single-shaft in order to investigate group interaction effects, derive p-y curves for reinforced concrete fixed head piles and to validate currently available p-multiplier models. The piles are identical in diameter of d=2 ft and were tested in similar soil conditions. The single pile as well as in three piles within the pile group were instrumented with internal sensor instrumentation to record pile curvatures. External instrumentation was used to control and measure the lateral displacement of the specimens. Experimental studies were supported with analytical models to enable comparisons and offer design recommendations. All test specimens were tested to structural failure and group interaction factors ranged between 0.8 at small displacement levels and increased towards unit near structural failure. A set of p-multipliers was found to reproduce an accurate fit to the available test data.

Jan 1, 2010

By Vladimir M. Korolev

The field studies conducted at the experimental-production sites allowed to develop the technology of arranging drilling piles in loess subsiding grounds over 25 m deep and over 250 mm in diameter, to select optimal compositions of flush fluids, to assess the carrying capacity and field of use of the piles under test and to produce a special equipment. The dependence of the ultimate axial pressing-in load on pile driving into the non-subsiding section, its diameter and method of fulfillment, as well as the ground moisture dependence of the specific ground resistance along the piles' side surface within the limits of the subsiding section were determined. The study results allowed to reduce the length of the work piles and the number of bars in the reinforcement frames. The obtained experimental data enable to give a preliminary assessment of the piles' carrying capacity under complicated engineering-geological conditions of subsiding grounds.

Jan 1, 2002

By Shamsher Prakash

Estimation of vertical load carrying capacity of a single vertical pile under earthquake loading is an important task of a design engineer. Lateral vibration of vertical pile is highly influenced by the magnitude of vertical load. Several load reversal, during earthquake loading introduce gap between pile soil interface which reduces its load carrying capacity and increases lateral motion. This paper presents a simple time domain numerical scheme to estimate the lateral pile response, considering the loss of contact of pile at pile soil interface, during impact and earthquake loading. The motion of the pile is limited in the vertical plane. Time domain has been discretised into small intervals. The non linearity of soil properties has been taken into account by discretised Winklers model with Wolfes frequency independent mass spring dash pot coefficient for geometric damping. Suitable software has been developed which keeps track of the load reversal point of each elements.

Jan 1, 1996

By P. Davies

The Hillside Smelter presently under construction at Richards Bay, Republic of South Africa, will be, on completion, the fifth largest aluminium smelter in the world. The site selected for this plant is underlain by sandy soils of variable density to depths of 30m or greater. In order to firmly establish pile founding depths required for alternative pile types in the variable subsurface conditions prevailing across the site, a pre-construction test piling programme was conducted incorporating piles instrumented with resistance strain gauges. The results allowed analysis of the relative contributions of end-bearing and shaft friction to the overall bearing capacity of each pile type and permitted comparison with the predictions of conventional static bearing capacity analyses. Conformance with acceptance criteria in respect of allowable pile head movements for single piles was also examined.

Jan 1, 1996

By Willie M. NeSmith

The use of drilled (screwed) displacement piles is an emerging sector of the United States deep foundation industry. During installation of these systems, a Ko to Kp environment is created in the materials surrounding the pile immediately prior to casting, and this condition results in increased shaft and toe resistance in soils where displacement leads to densification. Current continuous flight auger and drilled shaft design methodologies in the United States assume a Ko to Ka condition in the vicinity of the pile, and are thus an inappropriate starting point for static capacity analysis of drilled displacement piles. This paper examines constructability issues, and the sensitivity of performance to installation, and offers an empirical design methodology for drilled displacement piles. The proposed design process has been based on evaluation of 40 load tests, primarily in granular materials, and in a variety of geologic settings, and includes modification for soil types within the coarse-grained range.

Jan 1, 2002

By Georgette Hlepas

How often phrases like these have been made by project managers and project teams trying to explain why there has been cost growth, project delays and differing site conditions claims. But does it really take x-ray vision? Do we really approach geotechnical construction projects unprepared for the subsurface that may be encountered because we can't get the answer? Too often our industry seems to think the answer is, "yes." However, this is not because we can't understand the subsurface. All too frequently it is because a choice is made to save money or time by foregoing or shortchanging upfront subsurface investigations. This is accepting a risk at the beginning of the process and realizing it during construction. Case histories have proven time and time again that upfront investment in site exploration and constructing a ground model mitigates risk in design and construction. But how much do we prepare? What level of investigation (or investment) is appropriate? The answer of course, is it depends; how much risk are you willing to take for your project and what are the potential consequences?

May 1, 2022

By Mohammad T. Izadi

Piles are, often, used for transferring load from the super structure through soft consolidating strata onto relatively stiff uncompressible soils. Downward movement of the soft soil strata develops negative skin friction and dragload around the pile shaft, with time. Traditionally the induced dragload is considered in determining the pile bearing capacity. On the other hand, field measurements on instrumented piles show that negative skin friction is reduced by the magnitude of applied live load. A method for calculating the pile bearing capacity, driven through soft consolidating strata is presented. In this method, two allowable load-bearing capacities are calculated for each pile, live load plus dead load and dead load. The proposed method, substantially, increases the allowable load bearing capacity of piles compared to calculated values by the traditional methods.

Jan 1, 2001

By Manish Kumar

One of the recent advances in the field of testing of concrete piles is the Non-Destructive testing (NDT) of piles. This paper deals with a specific project where this technique was employed along with an extensive program of conventional testing methods to cross check the results. Conventional testing of the Bored, cast-in-situ piles involved taking full length concrete cores from piles to check physical properties such as core recovery, RQD, crushing strength and density of concrete. Additionally, a number of questionable piles were exposed and inspected and actual load tests were performed on selected piles. Concrete pour cards were used to compare actual Vs theoretical consumption of concrete. A direct comparison of the conclusions drawn from both these testing methods provided an excellent opportunity to better understand the intricacies of NDT technique. The study undertaken clearly indicated a need for developing clear guidelines and specifications for the use of this method of non-destructive testing of piles before the .method can be accepted as a useful quality control tool at the construction sites.

Jan 1, 1996

By Shawn Downey

A helical pile with in-situ grouted shaft was used to underpin the existing slab of a large retail store in the Edmonton, Alberta Canada area. The existing structural slab did not have the capacity to support the increased load requirements. The design to upgrade the capacity specified a drilled shaft as the deep foundation to underpin a portion of the slab. A helical pile was quoted as an alternate and ultimately won the bid based on the advantages of the system. After an ASTM D1143 Quick Load Test confirmed the axial compression capacity, 723 helical piles with grouted shafts were installed in 3 weeks underpinning 40% of the 93,000 ft2 (8,660 m2) building.

Jan 1, 2003

By Kirty Dave

Foundations in any contract are the most uncertain parts of the contract and most of the "Construction-Contract-Disputes" are either directly related to foundations or arise as 'Side-effects of changes in promises related to foundations. Foundation Engineering is defined as ' The art of selection, designing and constructing the elements that transfer the weight of structure to the underlying Soil or Rock." (Ralph B. Perk). This art started becoming a science since 1920, when scientific efforts to determine the behaviour of sub-surface materials were made. The art and science merged to give new techniques and the science started dominating the field as more and more refinement came in techniques to predict more accurately the characteristics of the sub-surface elements. Inspite of good thorough investigations and design, the contractual promises drafted could leave some room for differences between the parties and above all the prudency expected of both the parties may fall short of the expectations raised in the contract. This may give rise to disputes which may need to be resolved as per principles of law. This paper attempts to initiate a dialogue amongst Foundations-Engineers and Contractors as to how do we minimise the differences arising out of or related to contracts concerning "Foundations".

Jan 1, 1996

By Kenneth M. Berrry

A unique situation has developed at an abandoned coal mine in St. Clair County, Illinois. Subsidence features have been observed at the ground surface over the mine including settlement of a pair of bridges for Illinois Route 158. The Illinois Department of Transportation (IDOT) is currently replacing the two bridges. Foundation treatment for the two new bridges included backfilling the mine void. The light rail system for St Louis (MetroLink) is also constructing a bridge over the same abandoned coal mine less than 1000 ft from the Route 158 bridges. The new MetroLink bridge is being constructed using piles which extend through the coal mine and overlying bedrock in order to transfer the loads to below the mine floor. The differing foundation types for the IDOT and MetroLink bridges were due to geometry and economic factors involved with the individual structures.

Jan 1, 2001

By Trevor I. Addenbrooke

Stress reducing piles were used for the first time at the Queen Elizabeth II Conference Centre near the Palace of Westminster in London, UK. The inclusion of these piles directly beneath heavily loaded columns was to reduce the high anticipated bending stress in the foundation raft, and to eliminate local yield of the London Clay beneath the column locations. Load cells were placed in one of the stress reducing piles during construction. The data showed that the pile carried about 30% of the column load. This can be contrasted with conventional piled raft design where the pile carries upwards of 80% of the column load. The build up of load on the pile and pile displacement have been accurately reproduced using coupled finite element analysis. These numerical results demonstrate the value of geometrically simple axially symmetric analyses for modelling a pile-enhanced raft. On site, excavation preceded construction of the raft and subsequent pile loading. Failure to model this construction sequence caused the shear strength to mobilize at the base of the pile first, during loading, whereas following the construction sequence caused the shear strength to mobilize at the top of the pile first.

Jan 1, 2002

By Jeffery L. Ottesen

Early construction delays can jeopardize timely completion of subsequent work. As an early construction activity, and due to many unforeseen issues, deep foundation work inherently bears great potential for impacting the critical path of a planned construction schedule. This article describes two construction projects where delays related to deep foundation work forced the Contractor to consider various schedule recovery alternatives to mitigate those delays. Specifically, deep foundations on Vancouver BC's Millennium SkyTrain light rail extension and on a Mill Facility in the United States are discussed. This article cites examples of permitting delays, alleged design changes, differing subsurface conditions and changed construction methodology, the effect each problem had on the project, the mitigation means implemented by the Contractor to minimize adverse impacts of the problem, and Lessons Learned for each scenario.

Jan 1, 2002

By Barry C. Roth

A Real Time Automated Remote Reading Electrolytic Tilt Monitoring System was effectively deployed for monitoring an existing five story brick building during underpinning, shoring and excavation operations for a directly adjacent thirty-foot deep excavation. The monitoring system was comprised of four sets of uniaxial electrolytic tilt meters connected to a Campbell datalogger with multiplexer, cellular modem and solar power. The excavation was for the foundation and underground parking as part of a new 55 story tower complex. Challenges to the contractors and to our monitoring personnel which were addressed included a tight urban site contemplating property line to property line new construction with directly adjacent old existing buildings, buried concrete foundations from former site use, cohesionless pervious sandy soils and high groundwater. Highly variable and diurnal ambient temperature regimes due to adjacent building shadows required careful corroboration and application of temperature corrections to the raw data. Earth tides were suspected on a very small scale and investigated by correlation between the data and the local sinusoidal tidal ephemera. Incidental inadvertent contractor interference with the instruments during underpinning due to site constraints was readily detected.

Jan 1, 2007

By Dinesh R. Katti

Caissons which are locally known as well foundations, which may very in diameter from 30 m to more than 30 m and in majority of the cases having depth to diameter ratio between 1 to 1.5, are normally used to support piers of long span bridges or tall structures, which transmit high magnitude of axial load, horizontal thrust and moment. On the basis of depth to diameter ratio the foundation system appears to fall in the category of shallow foundations but due to deep excavation, it is observed that part of the moment acting on the caisson is shared by due the sides due to development of passive resistance. The problem is statically indeterminate and three dimensional in nature. To ascertain the various parameters needed for design, such as moment shared by base and sides, horizontal and vertical displacement and tilt, and base and side contact pressure diagrams need to be obtained from nondimensional relations of parameters with respect to D/B ratio derived from large scale model studies conducted by Katti etal at IIT, Bombay under MOT Project between 1976 and 1988 and later on at UNEECS. On the basis of above data on attempt is made to put forward guide lines for selection of parameters for design of caisson foundations / well for following cases for opening us some discussion. The cases are cohesive soil at the side and cohesive soil, or sand or soft rock or hard rock at the base.

Jan 1, 1996

By Pier Luigi Iovino

As Technical Director of the Naples, Italy based Fondedile, a geotechnical construction firm specializing in static restoration of structures, Fernando Lizzi, Ing., devoted over 30 years to the pursuit and advancement of static restoration and subsoil strengthening. Seismic events, construction of new structures on polluted and/or unstable soils in urban areas, and a need to carefully preserve and restore delicate, war-damaged historical structures, manifested the need for underpinning projects. Traditional construction methods and approaches, such as underpinning with additional foundation masonry, were not suitable and would have further jeopardized the stability of the structures. The introduction of the palo radice (root pile) revolutionized the field of underpinning. At the time of the first application of micropiles, the industry standard was driven piles. The drilled micropile was conceived and first implemented in the early 1950s, as an innovative means to underpin sensitive, historic structures and structures in urban areas. Specifically, the new construction technique was conceived as a less expensive alternative, designed to accept structural loads, be installed in limited access areas, in varied working and sub-surface conditions, which did not involve changing soil characteristics, and had minimal disturbance to the structure being underpinned, or to adjacent structures.

Jan 1, 2003

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