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By Chen Zhiquan

Author has exhaustively researched into soft ground through construction of a large open caisson on soft ground (muck) which weighs more than 4, 000 tons. To avoid any contingency during construction, we precompressed muck stratum with a sand cushion and consolidated it with sand piles before construction of the caisson. We made borehole surveyings and soil tests many times before and after ground treatment. Following the tracks of changes of the caisson at all stages of precasting, we surveyed a large number of data. On the basis of analysis of the data we changed the original construction plan of precasting in four stages and sinking in three stages into that of precasting in three stages and sinking in one stage. Through the practice of the whole caisson construction the author has advanced new theory of kinematic law for soil particles and the change's law for strength of muck during precompression of sand cushion and consolidation of sand piles.

Jan 1, 1991

By J. S. Ward

In a well-written set of contract documents, the probability of conflicts arising during the course of construction is minimized. However, no matter how complete may be the technical language in the contract plans and specifications, the possibility always exists that conditions may be found in the field that were not anticipated at the time the design was formulated. In foundation engineering work, this is commonly referred to as "differing site conditions." When such a conflict arises in the field, the most expedient manner of resolution would be for the parties to the contract to meet and to amicably resolve the issues rather than use the long and costly adversarial approach of the litigation system currently prevalent in the United States. This rapid solution to the construction conflict can be accomplished through an alternate dispute resolution technique that includes mandatory discussion, mediation and arbitration to be initiated immediately following the inception of the dispute and to be concluded in not more than 100 calendar days from the time the dispute originated.

Jan 1, 2010

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 Mai Yuanjian

The stabilization effect in large excavation slope with vacuum wellpoints system during construction of a dry dock located in Guangzhou is introduced in this paper. In-situ observations indicate that the effect of wellpoints for decreasing seepage in slope is remarkable even though the muddy sitty clay in it has poor permeability and the slope can remain its stability well. Meanwhile, a non-linear partial defferential equation has been set up to the whole unsteady seepage process as water level in the foundation pit excavated under water goes down to the bottom and so does the seepage in slope due to dewater by vacuum wellpoints system at the same time. And the finite-defference method has been used to solve the equation mentioned above, which differes from conventional wqy where the equation will be linearized firstly. Since the water heads in slope with wellpoints dewatering are more variable, it is necessary to keep non-linear. The calculation results are in good accordance with observation. Vacuum wellpoinnts for slope stabilization in this work is successful.

Jan 1, 1991

By Bernard H. Hertlein

The introduction of LRFD methods for structural design has been a gradual process by AASHTO, ACI, AISC, ASCE, and the FHWA, which has largely been ignored by the deep foundations industry. In 2007, however, the industry has been obliged to embrace LRFD for any deep foundations on projects involving federal funds. The authors are concerned that the risks caused by the need for, and the difficulty of providing, reliable quality assurance, will result in unnecessarily high safety factors that will defeat part of the purpose of LRFD. A primary attraction of LRFD for owners and engineers alike is that it promises more efficient design, and therefore cost reductions. Unfortunately, a key element of LRFD philosophy is often overlooked - that the applied safety factors can be rationally reduced, often allowing less material to be used, thus saving costs, but only if all the risk factors involved are identified and closely controlled. This means that both the quality of the materials and the quality of the construction work must be adequately monitored, and held to an acceptable standard. In the case of deep foundations, the soil in which the foundation is constructed is also a critical component that must be taken into account in the assessment of risk factors.

Jan 1, 2007

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 John Y. L Chen

This paper presents full-scale instrumented pile static compressive and tensile load tests to be conducted in the area of Pearl Harbor, Hawaii. Thousands of piles have been installed to support the existing piers and wharves in the Pearl Harbor area. Due to the absence of bedrock within practical depths, most of the piles use combined friction and end bearing. A new 925 feet (282 meters) long and 50 feet (12 meters) wide reinforced concrete wharf supported on pile foundation is planned. This paper will present results of soil investigation, laboratory testing, dynamic load tests during indictor pile driving and static pile load tests. The subsurface conditions consist of soft harbor sediment, young alluvium deposit, volcanic tuff rock formation and stiff old alluvium deposit. The load test piles consist of 20-inch (508 mm) square and 24-inch (610 mm) octagonal pre-stressed, pre-cast concrete pile and instrumented with embedded strain gauges. The length of the piles ranges from about 50 to 125 feet (15 to 38 meters). The test pile program consists of probing, driving indictor piles, dynamic load tests during indictor pile driving and static load tests. The standard loading procedure method was used during static pile load tests.

Jan 1, 2002

By Sherrill Gardner

Vibratory drivers have been used since the 1930s to drive and extract piles. Vibratory pile drivers have the capability of significantly decreasing pile installation time, especially in granular type soils. However, they have not been widely accepted because of the uncertainty in estimating the bearing capacity of the driven pile. When driving bearing piles, the industry standard method for obtaining load carrying capacity of a pile installed with a vibratory driver is to redrive with an impact hammer. The advantage of improved productivity is lost with the redrive procedure. Currently, there is no other method to predict the capacity of these bearing piles installed with a vibratory driver. The Naval Civil Engineering Laboratory (NCEL) is making progress towards being able to estimate the bearing capacity of these piles. This paper describes field testing and corresponding analytical modeling of the vibratory driver-pile-soil system. The following sections describe the development of the numerical model and techniques for collecting field data. A discussion of the prediction of the pile driving process based on field test data is followed by suggestions as to the additional work that should be done to further verify the model to a point where it can be used with confidence.

Jan 1, 1987

By Kanagarajah Ravishankar

Drilled shaft (caisson) foundations are extensively used in the past. In the central part of New Jersey, the soils consist of silt and clayey silt overlying Triassic age shale bedrock. The shale is friable and generally severely weathered and highly fractured. The shale crumbles readily into small fragments. In general, the shale is encountered in shallow depth. Subsurface investigations indicated that the upper part of the shale is very soft, highly weathered, and able to advance through soil exploration methods. The underlain formation is relatively hard and required rock coring techniques for sapling. Individual core recoveries ranged from 10 to 100 percent and Rock Quality Designations (RQD) vary from 0 to 90 percent. Although several methods available to estimate the axial capacity of drilled shafts, it is a difficult task for the designer choose the suitable method due to self disintegrate nature of the shale. In the recent years several bridge foundations have been constructed using drilled shafts founded on shale rock in the vicinity of the central New Jersey. Based on load tests carried out on drilled shafts during construction, subsurface exploration, and laboratory tests, suitable methods for determining axial capacity of drilled shafts is analyzed. This paper presents the findings of the field tests and suitable methods to determine the axial capacity of drilled shaft founded on soft shale. Key words: Drilled shaft, axial capacity, Osterberg load test, shale.

Jan 1, 2006

By K. Fujita

In order to deal properly with the fundamental aspects of pile construction, the following problems and their solutions are introduced: For driven piles - stresses, damage, movements of surroundings, compaction of ground, deviation of pile direction and location, selection of pile hammers and penetrability of piles are important factors. For drilled piles -loosening of the ground, supports for boreholes, minimizing ground loosening and defects are critical items. Attention should be given to changing soil characteristics. Also, supervision by experienced engineers and good workmanship by skilled laborers are recommended to ensure the quality of the piles.

Jan 1, 2010

By Michael W. Neill, O&apos

The performance of foundations that combine the high bearing capacity of rafts (mats) with the settlement reduction capability of piles is described through a summary of 24 case histories. Structures included are high-rise commercial office buildings, governmental buildings, industrial facilities and residential buildings, and subsurface conditions range from soft clay to stiff soil overlying rock. Pile types are bored, augered and driven. Since piled rafts are not commonly used in the United States, most of the case histories are from overseas. In all cases the performance of the foundations was monitored during and after construction. Particular emphasis is placed on measured settlements of the piled-raft foundations, distribution of resistance between piles and raft, and general analysis methods that were used by the designers for various geotechnical circumstances. Finally, patterns of behavior are summarized. In most cases, the piles were not designed to mobilize their full capacities under sustained loading of the foundation; therefore, under long-term loading conditions, the piles typically carried more load than the raft. This paper is the result of a study conducted by ITC-18 (Deep Foundations, Willem Van Impe, Chair) of the International Society for Soil Mechanics and Geotechnical Engineering by a subcommittee chaired by the author.

Jan 1, 2003

By Ramdane Bahar

The new Algiers airport building is a reinforced concrete building of more than 80 thousand square meters of floor slabs. It is located at Dar-EI-Beida, near the old passenger terminal, about 20 km east of Algiers. The project is designed to receive about six millions passengers annually and leaves the possibility of future extension. Due to the presence of a top layer of compressible soil and great concentrated loads transmitted to the foundations, the building is to be founded on 1730 bored piles of 1.2 meter diameter varying in length between 14 and 28 m. Construction work started in 1986 and was interrupted in 1996 due to financial difficulties when the structure was almost complete. The structure was left unattended for more than three years without any weatherproofing and in 1999 a new firm was appointed to complete the work and hence an evaluation of the existing structure was necessary. This paper describes and discusses the foundation design, construction supervision, site quality control and assessment by the parallel seismic method of the deep foundations built in cohesive soils. The variation in soil conditions and identified geotechnical and hydrogeological problems associated with the development of the area, required a thorough knowledge of the soil conditions. A variety of tests, involving more than 200 locations, were carried out. The ground investigation, pile tests as well as different problems encountered during piles construction, are presented.

Jan 1, 2002

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 David R. Black

Foundation problems due to collapsible and expansive soils are well known throughout the arid western United States. Millions of dollars are spent annually to counteract the effects of such soils for both new foundations and existing foundations suffering from settlement or heave. Over the last 20 years helical screw piles have come into wide-spread use as a permanent deep foundation element for these problem soils, especially in the arid western United States where, in some areas, they are a standard of practice. Independent research resulting in recognition by every national building code in the United States has legitimized helical screw pile technology. Once thought of in terms of light structural underpinning, helical screw piles of today are designed to take heavy structural loads, vertical and lateral, tension or compression, including seismic loads. With proper pile grouping, design capacities for column loads over 4,500 kN (1,000 kips) are attainable. This paper discusses design considerations specifically dealing with collapsible and expansive soils: soil investigation parameters, predicted settlement and long-term creep, heave in expansive soils, downdrag in collapsible soils, shaft slenderness buckling, maintaining shaft alignment during installation, refusal condition, water migration along the shaft, lateral loading, cyclical loading for seismic loads and machine foundations, corrosion, helix durability during installation, the installation torque vs. capacity equation, and design methodology. The paper concludes with several case histories where helical screw piles were used for new structural foundations and to underpin existing failed foundations in St. George, Utah, Cedar City, Utah, and Denver, Colorado, USA, sites of some of the most expansive clay and collapsible soil in North America. Soil descriptions and performance histories are presented.

Jan 1, 2002

By Tae Hwan Lee, Jun-Shin Lee, Daejin Kwag, Sangchul Bang, Gerard T. Houlahan, Moo Sung Ryu

"Geotechnical engineers have been installing innovative, permanent underwater foundation systems utilizing suction buckets for the offshore industry since the early 1980s (Senpere and Auvergne, 1982). This foundation system has been successfully used on numerous and various types of offshore structures in a wide range of environments. Suction buckets have numerous advantages compared to conventional underwater foundation systems. The more notable advantages include easy installation, large loading capacity, low noise and retrievability. The application of reduced water pressure inside the bucket facilitates the installation of the suction buckets, where a suction pump attached at the top of the bucket can accomplish the entire driving operation. Because of this efficient operation, very large suction buckets can be driven into the seafloor, which eliminates the use of a large number of small piles.In Korea, one of the most economical and reliable renewable energy sources is wind power; however, onshore wind power generation has encountered many problems, such as the lack of favorable sites and public concerns about noise and environmental damage. Consequently, offshore wind power generation has attracted increasing attention due to its abundant potential, high efficiency of grid connection, and availability of easy expansion.In November 2011, the government of Korea announced a national offshore wind power development roadmap, which targeted its offshore wind power generation with the goal of becoming one of the top three nations in the world for offshore wind power generation. Korea Electric Power Corporation Research Institute (KEPRI) is the main research arm of the Korea Electric Power Corporation (KEPCO) and conducts research and development on electricity, power generation, renewable energy and other energy-related matters. KEPRI ultimately provides forefront knowledge and leadership to KEPCO with respect to energy and related areas for its near- and long-term needs. Financial support for the overall project, of which the suction bucket foundation system installed for the pilot phase wind turbine is described below, was provided from the New and Renewable Energy Program of the Korea Institute of Energy Technology Evaluation and Planning funded by the Korean Government Ministry of Trade, Industry and Energy"

Jan 1, 2017

By Tae Hwan Lee, Jun-Shin Lee, Daejin Kwag, Sangchul Bang, Gerard T. Houlahan, Moo Sung Ryu

"Geotechnical engineers have been installing innovative, permanent underwater foundation systems utilizing suction buckets for the offshore industry since the early 1980s (Senpere and Auvergne, 1982). This foundation system has been successfully used on numerous and various types of offshore structures in a wide range of environments. Suction buckets have numerous advantages compared to conventional underwater foundation systems. The more notable advantages include easy installation, large loading capacity, low noise and retrievability. The application of reduced water pressure inside the bucket facilitates the installation of the suction buckets, where a suction pump attached at the top of the bucket can accomplish the entire driving operation. Because of this efficient operation, very large suction buckets can be driven into the seafloor, which eliminates the use of a large number of small piles.In Korea, one of the most economical and reliable renewable energy sources is wind power; however, onshore wind power generation has encountered many problems, such as the lack of favorable sites and public concerns about noise and environmental damage. Consequently, offshore wind power generation has attracted increasing attention due to its abundant potential, high efficiency of grid connection, and availability of easy expansion.In November 2011, the government of Korea announced a national offshore wind power development roadmap, which targeted its offshore wind power generation with the goal of becoming one of the top three nations in the world for offshore wind power generation. Korea Electric Power Corporation Research Institute (KEPRI) is the main research arm of the Korea Electric Power Corporation (KEPCO) and conducts research and development on electricity, power generation, renewable energy and other energy-related matters. KEPRI ultimately provides forefront knowledge and leadership to KEPCO with respect to energy and related areas for its near- and long-term needs. Financial support for the overall project, of which the suction bucket foundation system installed for the pilot phase wind turbine is described below, was provided from the New and Renewable Energy Program of the Korea Institute of Energy Technology Evaluation and Planning funded by the Korean Government Ministry of Trade, Industry and Energy."

Jan 1, 2017

By Dan A. Brown, Rich A. Lamb, Paul J. Axtell

"Over the last 10 years, the Minnesota Department of Transportation (Mn/DOT) has had a very active program of replacing many major bridges, large structures spanning the Mississippi River. The deep foundations for these new structures include both drilled shafts and large diameter open-ended driven steel pipe piles. Most of these projects included load tests, both axial and lateral.The geology of this area of Minnesota includes some interesting foundation challenges, including highly organic and compressible very soft silts and clays to very dense sand and gravel overlying sedimentary bedrock. In some cases scour requires embedment into rock, and the bedrock formations may range from very soft sandstone to very hard dolostone. Artesian groundwater conditions can sometimes complicate drilled shaft construction, but the rock is otherwise very favorable for drilled shafts. Experience with the open-ended driven steel pipe piles (typically 42 and 48 in, 1.07 and 1.2 m diameter) suggest that these piles most often penetrate even dense granular materials to achieve bearing on rock. Experiences with drilled shafts socketed into the soft sandstones demonstrate that these rocks provide very favorable conditions for drilled shafts, so long as suitable construction practices are followed. Here we present several recent case histories regarding the foundation design and construction of major bridge projects in the vicinity of Minneapolis, Minn., including the Wakota Bridge, the I-35W replacement, the Lafayette Bridge, the Hastings Bridge and the St. Croix Bridge. Some lessons learned from construction and load testing of both types of foundations are described along with implications for design in similar soil and rock conditions."

Jan 1, 2013

By David R. Shields, Michael T. Bracher

"The $330 million (U.S.) Dana-Farber Cancer Institute’s Yawkey Center for Cancer Care (Yawkey Center) sits in the heart of Boston’s Longwood Medical Area. The Yawkey Center is a cutting-edge cancer care facility that houses Dana-Farber’s adult clinical care and clinical research programs. Standing 14 stories above grade, it includes 7 stories of underground parking extending 75 ft (23 m) below ground. The structure is on a 198 by 186 ft (60 by 57 m) site sandwiched between Dana-Farber’s 13-story Richard A. and Susan F. Smith Research Laboratories Building, the Medical Area Total Energy Plant (MATEP), Jimmy Fund Way, and Brookline Avenue, a busy four lane artery through the heart of the Longwood Medical Area. Together with Simon Design Engineering, the project structural engineer, GEI Consultants designed an innovative foundation and excavation support system to isolate the building from ground vibrations generated by the adjacent MATEP power plant. In effect, the Yawkey Center is a 21-story free-standing structure that starts 7 stories below grade.The MATEP facility provides power for 9 million sq ft (840,000 sq m) of occupied space in the medical area. There are six 32-cylinder diesel engine generators in the facility that produce low-frequency ground vibrations in the 10 Hz range, similar to the natural frequency of typical building elements. The resonant response of the Yawkey Center building structure to these ground vibrations would affect the performance of sensitive medical research equipment and cause an unacceptable environment for clinical care.The soil profile at the site consists of stiff clay, fine sand, glacial till, and bedrock consisting of hard metamorphosed conglomerate. In-situ measurements of ground vibrations performed in boreholes showed that there was little attenuation of the vibrations with depth in the soil layers overlying the bedrock, but the vibration amplitude in the bedrock was markedly lower than in the overlying soil. Based on this data, an innovative foundation system was designed to support the building on bedrock located up to 110 ft (34 m) below ground surface, while isolating it from the surrounding soil. This was done by physically separating the below-grade parking garage floors from the perimeter foundation walls to create a free-standing structure supported on the bedrock"

Jan 1, 2012

By R. Paul De Bruyn

A. Crane Check List -- Make -- Model -- Year of Manufacture -- Where is load chart? Is it for this crane? -- Boom style and length -- Boom tip drawing (sketch) for fixed lead connection. Has the crane manufacturer been consulted on the point of attachment? -- How many drums; diameter and length of wire rope. -- Is the single part line pull enough to lift pile or hammer on single part line? -- What is the effective weight of the whole driving system - leads, pile, hammer, etc? -- Are there any auxilliary hydraulic systems? Are the line pulls on these adequate to lift the pile or hammer? -- What is the anticipated working radius? Will the spotter collapse to that length? -- Nature of foundation under crane - barge, marsh, unstable sand, etc. -- Does the crane meet OSAH and state regulations -current certification. Note - the operator is responsible for compliance with regulations. -- Is there any extra weight added to counterweight by compressors or hydraulic systems? What does crane manufacturer say? Consult factory before adding.

Jan 1, 1990

By Tim Siegel, III Fondren, Billy Camp

"INTRODUCTIONThe new $650 million power block at Santee Cooper’s Cross Generating Station in Cross, South Carolina is being constructed on driven pre-stressed concrete (PSC) piles. S&ME, as geotechnical subconsultant to Parsons Energy and Chemical Group, was responsible for pile analysis and design to meet the site’s geotechnical and seismic challenges. Selection, analysis and design of the PSC piles included consideration of the following:• Column and equipment support loads ranging up to 500 to 1000 kips (2224 to 4448 kN).• Incorporation of the 2000 International Building Code seismic provisions.• A thick upper soft clay and loose, liquefiable sand.• Potential for karst-related features in the calcareous Santee Limestone.GEOTECHNICAL CHARACTERIZATIONThe near-surface site geology consists of (in order of increasing depth): (1) Pleistocene sediments, (2) the Santee Limestone (considered part of the Orangeburg Group) of Eocene age, and (3) the Black Mingo Formation of the Eocene/Paleocene age (refer to the shear-wave profile in Figure 4). Pleistocene clays and silts are generally soft and will settle significantly if subjected to loading by heavy grade-supported structures while the interbedded sands are generally loose. Where submerged below the shallow groundwater table, the sands were determined to be liquefiable during a strong earthquake.The Santee Limestone is a nearly white to yellow fossiliferous and partly glauconitic rock consisting chiefly of calcium carbonate. Observations of the rock core samples from the site indicate that it can range from hard crystalline limestone (primarily in thin layers) to a lightly cemented sand. In terms of rock strength, the Santee Limestone is generally very soft to soft, depending on the cementation and other depositional characteristics."

Jan 1, 2004