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By Brian Littlechild

Whilst there is much innovative work being undertaken in South East Asia in the space allowed in this paper we have settled on describing in more detail the work that has been done with shaft grouting of deep foundations and piles founded in rock both in end bearing and socket friction. The paper is necessarily in two parts. The first part is about the application of shaft grouting since its introduction to the region some eight years ago. It describes, for the first time, much of the detail of the different techniques used and the construction and the design benefits achieved with shaft grouting in five countries in the region. The second part outlines the enhancements achieved in the design of piles founded in rock and brings together the results of 10 years of test loading. This includes the load testing of 1.2m to 1.5m diameter piles to a maximum of 30MN on granite and a recent programme of tests on a wide range of strong rock types in Hong Kong. The ground conditions for these deep foundations vary widely, from sedimentary soils to in situ weathered granite and meta-sedimentary rocks. The construction techniques include barrettes constructed using mill techniques and bored piles formed under bentonite and water using both oscillators and rotators.

Jan 1, 2000

By Pirooz Barar

The new Stanley Hall building will house the center for bio-engineering and technology research for the UC Berkeley campus. The structure is located at the northeast part of campus, adjacent to Donner Lab, on the west side of Galey Road, approximately 600 ft. from the Hayward Fault. The building site has a complex geological formation. To the east there are clayey soil shale formations, and to the west there is greywake shattered sandstone. The water table is at 10 ft. below grade. The structure will consist of 6 levels below grade and 8 levels above grade, which calls for an 83 ft. deep excavation on the northeast side. There is an approximately 35 ft. grade differential between the east and west sides of the building. Because of this severe grade differential, as well as high water tables, the lateral forces on the building due to uneven earth pressures would have been 2 times the magnitude of the seismic forces. To mitigate the lateral earth pressures, a permanent Soil Nailed Wall, integrated with the structural system of the building was designed. PB&A, Inc.?s in-house design program ?Winslope? was utilized to design the system and the data obtained from a rigorous monitoring program, were used to calibrate several computer runs using Plaxis program.

Jan 1, 2004

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 Mohamed A. Mansour, Ahmed M. Soliman, M. H. El-Naggar

"Grouted helical piles allow significant increase in pile capacity with low additional cost over that of conventional helical piles. They can be particularly advantageous in sites where installation disturbance can reduce or even eliminate the pile shaft resistance. For helical piles with slender shafts, a grout column offers increased buckling resistance under compression loading, and may reduce the potential settlement required to mobilize the bearing component of their plates. This paper investigates the performance of grouted helical piles installed in loose sand. Grouted helical piles were constructed and tested in a controlled laboratory environment. Helical piles with hollow pipe shaft and single helix were grouted during installation. The grout was injected into the soil under high pressure through two nozzles placed above the piles helices. The load test results showed significant improvement in the performance and load carrying capacity of the helical pile due to the formation of a cylindrical grout column along the entire shaft leading to a higher shaft resistance contribution to the total pile capacity. The results suggest that grouted helical piles with slender hollow shaft could be used to support large structural loads. INTRODUCTIONHelical piles are widely used as a deep foundation system for different engineering applications. They represent an attractive foundation option because of their cost effectiveness, ease of installation even in limited access areas, low levels of noise and vibrations, and their ability to be installed through ground water without casing. In addition, they allow immediate loading upon installation. Helical piles are installed into the ground by applying a mechanical torque to the pile head. The installation torque monitoring provides a kind of quality control during the construction of helical piles. It could be used in predicting the ultimate pile capacity using several capacity-torque correlations (Livneh and Elnaggar 2008; and Hoyt and Clemence 1989).However, helical piles installation can cause soil disturbance within the annular zone affected by the pile helices. This disturbance can introduce fissures within the pile cylindrical failure surface (Vesic 1971; Mooney el al. 1985; and Zhang 1999). Thus, the shear strength of the soil decreases along the affected zone. Bagheri and El Naggar (2013) evaluated the installation effects of helical piles in sand. They reported that as the helical blade proceeds into the ground, sand within the cylindrical path circumscribed by the helices experiences torsional and vertical shearing accompanied by sand displacement and stress changes. This process is more pronounced in the case of multi-helices and large diameter anchors. Bagheri and El Naggar (2016) evaluated the installation effects of helical piles in structured clay. They indicated that the behavior of the helical pile and its capacity are significantly affected by the degree of soil de-structuring induced by the penetration of the pile shaft and helices. In addition to the installation disturbance, helical piles have other drawbacks including; high potential settlement required to fully mobilize the bearing component of their plates, low buckling resistance of their slender shafts, and the incomplete rigidity of the coupling joints along the pile shaft that allow some lateral movement under compression loading (Vickars and Clemence 2000)."

Jan 1, 2016

By H. Mori

This paper describes a new borehole loading test using a self-boring instrument appropriate for dense sandy soils and stiff clayey soils. The results of loading tests for the bearing strata of deep foundations according to this method are also presented. This method has been applied to the study on the settlement behavior of heavy foundations resting on dense sand, stiff clay or soft rock in Japan.

Jan 1, 2010

By Han Jie

The results of full scale plate load tests on stone columns on soft clay in coastal areas are presented in this paper. Four load tests were made, two of which were performed on the ground treated with stone columns, one on an isolated stone column and the last one on the untreated ground. For a given stress range, the settlement of the rigid plate, the stress concentration factor, and the excess pore water pressure were measured. It is found that the distribution of vertical stress beneath the rigid plate supported by the composite ground of stone columns is very different in shape from the one by the untreated ground, that the stress concentration factor has a relation with the stress level and time, that the stone columns increase the bearing capacity up to by 2 times, and that the ground stabilized by stone columns is of great advantage to keep the foundation stable.

Jan 1, 1991

By Hajialilue Bonab M.

The soil-pile interaction under lateral impact loads is not yet completely well known. Many tests on single piles under static lateral loads in centrifuge have been performed and P-y curves have been determined at different levels of the pile in soil. Following these static tests on piles, a large program is undertaken with the same piles submitted to impact loads. The pile equipped with various pile caps has been impacted under variable amplitudes of shock. The behavior of the pile under different impacts was studied and dynamic parameters of the soil-pile system have been determined. Many cases of loading constituting various load histories have been analyzed. They are resulting from parametric centrifuge tests run out, on the one hand with constant and cumulative impacts and on the other hand, variable and cumulative ones. The Influence of each type of loading was studied. Using a finite element method, a non-linear pile-soil system was conceived and a transient dynamic analysis have been performed. The results of the non-linear analysis and experimental data were compared giving a good agreement.

Jan 1, 2002

By Gary L. Seider

Chance, a Division of Hubbell Power Systems, Inc., in conjunction with Sailors Engineering, Inc. has updated its Helical Design Capacity Software. This latest version, ?HeliCAP® v2.0?, is a state-of-the-art helical anchor and pile capacity program designed to operate in the Microsoft® environment. The program calculates the tension and compression capacity along with the frictional capacity, if applicable, of CHANCE® Civil Construction helical anchors and piles using design theories and methods adopted by Chance. This paper details the current state of practice employed by the software in the design methods and installation methodologies of helical anchors and piles.

Jan 1, 2007

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 George J. Tamaro

The design and construction of foundations in the New York City area are usually dictated by the widely varying geologic conditions encountered in the five boroughs, particularly along the spine of Manhattan Island. Rock extends well above sea level at the northern reaches and falls to depths in excess of 250 m at the barrier islands at the southern extremities. These highly variable geologic conditions, significantly affected by glacial activity, dictate different design and construction approaches throughout the five boroughs of New York City. Extensive rock removal is required at the north while long piling is dictated in the south. Similar changes can occur within a project site on Manhattan Island. This paper will describe these conditions in general, will identify the various solutions used to solve these problems and will summarize various foundation types used in the New York City area.

Jan 1, 2000

By W. H. Craig

Techniques have been developed for installing model piles into beds of soil under high sustained acceleration levels aboard a centrifuge. These piles have been subjected to static and/or cyclic lateral loading in order to assess their performance and provide a data base for assessment of various design techniques for laterally-loaded single piles. From measured bending moment profiles the so-called 'p-y' curves have been deduced using fifth order splines for curve fitting, followed by subsequent differentiation and integration. The results show some divergence from the predictions of the semi-empirical designs, but these latter are generally found to be acceptable.

Jan 1, 2010

By A. A. Gupte

Auger piling system which was developed in the United States in the 1940's is gaining acceptance in many parts of the world. Although primarily used to support foundations, the system is very useful for many other applications such as soil anchors, temporary and permanent earth retention systems, restricted headroom piling and underpinning of existing foundations. In this paper, review of current construction design techniques for the Auger piling system for earth retention and underpinning of structures is presented.

Jan 1, 1989

By Martina Balic

Dynamic properties of the drilled shaft foundations supporting Doremus Avenue Bridge were determined by forced vibration testing. The main objectives of the substructure testing at Doremus Avenue Bridge were: (1) site evaluation with respect to the dynamic soil properties, and, (2) shaft evaluation for the purpose of definition of their dynamic stiffness. The site characterization entailed crosshole testing for the purpose of evaluation of the shear modulus profile. The drilled shaft impedance evaluation was done through forced excitation using an electromagnetic shaker. The responses of the tested shaft, as well as the response of adjacent shafts, were measured for the purpose of evaluation of the shaft interaction. To gain a better insight into the shaft dynamics, one of the shafts was instrumented with five triaxial geophones distributed along the full length of the shaft. The scope and results of the site characterization, shaft impedance and shaft interaction evaluation are presented.

Jan 1, 2004

By Kyle M. Rollins

To improve our understanding of lateral resistance of pile groups, a series of lateral load tests were performed on a full-scale pile group using both static and dynamic loads. The pile group consisted of nine 0.6 m-diameter steel pipe piles driven into clay. During the static tests, the load was cycled fifteen times to evaluate the drop in lateral resistance that would occur due to repeated loading and the formation of a gap. The peak load typically decreased by about 15% from the initial cycle to the last cycle. The load carried by each pile was also measured and there was a significant drop in resistance for the piles in the trailing row relative to the leading row. The dynamic force was applied using the Statnamic loading system which produced a lateral force of 3500 kN (787 kips) in about 0.1 seconds. In two cases, dynamic loads were applied following application of 15 static load cycles. In these cases, the dynamic lateral resistance was about the same as the static resistance, likely due to gaps around the pile. In three other cases, the dynamic force was applied prior to the cyclic loading. In these cases, the dynamic resistance was 30 to 60% higher than the static resistance. Simplified analyses suggest that the difference in resistance could be attributed to damping produced by the soil surrounding the piles during the virgin loading.

Jan 1, 2002

By Gordon King

This paper presents a case study of large diameter continuous flight auger (CFA) piles and drilled shafts utilized for foundation support of a series of heavily loaded cement plant structures at the Suwannee American Cement (SAC) Plant in Branford, Florida. The high loads and exacting total and differential settlement criteria when combined with a highly variable subsurface geology provided a challenging design scenario. Fully instrumented static pile load tests were performed to determine design parameters in the variable weathered limestone bedrock. Ultimate side friction values ranged from 2 to 8 tsf within the limestone, resulting in the requirement for CFA piles up to one meter (approximately 40 inches) in diameter and socket lengths of up to 40 feet. At several localized areas, the limestone bedrock was in excess of 60 feet below grade, requiring the use of cased drilled shafts to depths on the order of 80 to 90 feet. An integral part of the production pile installation was the use of instrumentation to monitor drilling and concreting parameters. Calibration of drill rates, torque and auger rotation with rock quality was performed to allow monitoring of the soil stratigraphy at each pile location. When combined with the results of the instrumented load testing, the monitoring of drilling parameters allowed confirmation that sufficient socket length was achieved within the quality of rock present at each and every pile location.

Jan 1, 2003

By Lin Li

A reliability based analysis method for a drilled shaft stabilized slope system is presented in this paper. In the past effort, a deterministic method using the limiting equilibrium method of slices for determining the global factor of safety of a slope reinforced by a row of drilled shafts was developed using the soil arching concept. The drilled shaft stabilization mechanisms for the slope were treated as the drilled shaft induced soil arching, which reduces the driving forces on the down slope side of the drilled shaft. The effect of drilled shafts induced soil arching on the reduction of the driving stresses in the limiting equilibrium slope stability analysis was quantified by the load transfer factor through extensive finite element simulation studies. A semi-empirical equation was also developed for expressing the load transfer factor as a function of the soil properties, including strength parameters and unit weight as well as the slope geometry and soil profile, the location and spacing of the drilled shaft, and the dimension of the drilled shaft. However, due to the inherent uncertainties of the soil properties and the model error of the semi-empirical load transfer equation, a modification of the deterministic method into a probabilistic method is developed in this paper. The Monte Carlo statistical method is used to generate random variables for the soil strength parameters based on the prescribed probability characteristics, including mean, COV, and the probability distribution function. In addition, the modeling error of the load transfer factor is also treated as a random variable in the Monte Carlo simulation method, in which the mean, COV, and probability distribution function for the bias of the semi-empirical equation are used. The developed theories were coded into a computer program for analyzing complex slope geometry and slope profile conditions. Two examples are shown in the paper to illustrate the analysis results of the developed probability approach for determining the reliability of a drilled shaft stabilized slope system.

Jan 1, 2017

By Z. C. Chen

Based on the analysis of load test data of long floating piles in soft soil regions, the expressions of load-transfer function of pile shaft and tip for soft soils are presented in this paper, and the data of cone penetration test are suggested to use for calculating the parameters of load-transfer functions. For the loads of pile within the range of the working load of pile, the estimated pile stiffness by the suggested method in this paper are in satisfactory agreement with the results of load tests. The current Vijayvergiya's method and Satowa's method also are used to calculate pile stiffness in soft soil for comparison.

Jan 1, 2010

By Michel Bustamante

The original Cistercian Lure abbey situated in eastern France and built in the second half of the 16th century, has become nowadays an administrative building. Because it has been founded on poor ground conditions and inadequate foundation scheme, the abbey has suffered severe structural distortion. In 1992 an inspection revealed new extensive damages which led to a general refection together with a foundation underpinning. Micropiling was the selected method. Movements recorded over a period of 6 years after underpinning completion are presented.

Jan 1, 2002

By Wolfgang G. Brunner

In the far north of Uttar Pradesh Province in the Indian Himalayas, the 280 MW Dhauliganga hydroelectric power plant is under construction by National Hydroelectric Power Corporation (NHPC), a state- owned enterprise, and a joint venture of Kajima Corporation of Tokyo and Daewoo Corporation of Seoul. This project sets out to develop the lower section of the mountain cascade of the Dhauliganga River, a tributary of the Sarda River, with a 311 m gross head. The 1360 km2 mountainous catchment area is bounded in the north- east by the Chinese border and in the south- east by the Nepalese border. The dam project is located in a remote area north of the principal town of Darchula of the upper Sarda valley, which is one of the seismically most active regions of India. The 56 m high rock fill dam, which will be the first of its kind in India, is faced with concrete and has a 1 m thick, at its crown 270 m long and over 70 m deep cut- off wall of plastic concrete below its toe. The cut- off wall, with a total area of 7500 m2, is constructed by a combination of Bauer hydraulic grabs, assisted by chisels and a Bauer BC 40 cutter which enables the overlapping joint system to be installed, guarantees optimum verticality and enables the cut- off to be keyed into the bedrock formation.

Jan 1, 2004

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