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By John E. Lens

Minutes after the Friday afternoon October 16, 2009 announcement that the 80 year old Lake Champlain Bridge was closed to traffic out of concern for public safety, emergency detour planning started at VTrans and NYSDoT. The closure severed a cross-lake link between Addison, VT and Crown Point, NY, which created a 76 mile detour and significant hardship for commuters, farmers working on both sides of Lake Champlain, and businesses relying on both traffic and employees commuting between Vermont and New York. Rehabilitating the bridge was determined to be economically and technically unfeasible and the design of a replacement bridge was accelerated for a spring 2010 construction start. In the meantime, a temporary ferry alternative was to be rushed into service beside the original bridge by February 2, 2010. This paper presents the case history of the fast-tracked ferry dock design and construction on the Vermont side. Twin 300-foot-long pile supported approach spans, a loading slip system and ice deflectors were designed, fabricated and constructed in 90 days in the fall/winter of 2009-2010. This chronicles the project from initial concepts through the extraordinary cooperation between state and federal agencies, and near round-the-clock winter construction on Lake Champlain. This project and its companion project on the New York shore succeeded by virtue of exceptional cooperation between seasoned regulatory, design, and construction participants and warrant this case-history presentation of the Vermont project to share within the industry as an example of overcoming extraordinary challenges.

Jan 1, 2011

By James E. Parkes

The Silver Spring Transit Center is a new three-level transit center that will include bus loops for County, Metro and intercity buses, parking, and retail space. It replaces an existing bus station and connects to a busy metro rail station in downtown Silver Spring, Maryland. Significant site constraints in both plan and profile had to be dealt with in developing a design for support of the structure. Over 90 rock-socketed drilled shafts ranging in size from 3 to 7 foot in diameter were ultimately used to accommodate the limited space and large column loads, and to adapt to the variable rock surface at the site. Site access during design was limited due to the existing active bus station, so contract documents were adapted to include further explorations. Differences in anticipated and actual field conditions regarding the depth, quality, and variability of the rock had to be overcome in construction. Osterberg Load Cell testing during construction allowed for verification and optimization of the shaft design. Additional issues dealt with on this constrained site in an urban setting included construction staging issues, such as working around specialty contractors for tieback walls, blasting operations for rock excavation, productions issues for hard bedrock, as well as coordination issues with third parties, most notably the Washington Metro Area Transit Authority. Aspects of the foundation design and optimization, preparation of the contract documents to deal with the complicated nature of the project, and lessons learned from construction are also discussed.

Jan 1, 2011

By Walter E. Vanderpool

Three drilled foundations for an elevated water-tank were instrumented, tested and monitored during construction and the first two years in service. One shaft was load tested by the Osterberg method. A void was detected in one shaft by cross-hole sonic logging, pulse-echo logging and concrete coring. The void was instrumented, hydrostatically tested and pressure grouted. The shaft was ?abandoned? and replaced by two smaller shafts with a straddle beam cap. One of the replacement shafts and the cap were instrumented. The strain that appeared in the abandoned shaft, the replacement shaft and the cap were monitored during the remainder of the construction, through the commissioning test and the first two years of service. The results demonstrate the precision and sensitivity of the vibrating wire strain gage.

Jan 1, 2004

By Naresh Koirala

The Greater Vancouver Regional District completed installation of a 2.5 Km long, 2400 mm diameter concrete sewer in Delta, British Columbia in 2000. The sewer traverses through area of peat and soft ground. The ground investigation along the sewer alignment consisted of cone penetration tests and auger drilling with standard penetration tests. The gravity sewer is supported on precast, pretensioned spun concrete piles imported from Malaysia which had never been used for a major project in North America. The capacities of the installed piles were tested using pile driving analyzer (PDA) and three static load tests. A total of 46 PDA tests were carried out during pile installation. The paper describes the pile vetting process the owner went through prior to accepting the piles for use in the project and performance of the piles. It compares the pile capacity estimated from the PDA tests with that estimated from soil mechanics methods using data from cone penetration tests and standard penetration tests. The ranges of estimated capacities calculated by different methods are discussed from design capacity selection considerations.

Jan 1, 2004

By Peter Faust

The foundations for the new South Viaduct Bridge in San Francisco were extremely challenging due to the requirement for very large and deep piles installed adjacent to historic structures. Drilled shafts up to 12? foot in diameter were constructed to a maximum depth of 200? feet in alluvial soils and Franciscan Bedrock using an oscillator system for the installation of the permanent steel casing. This paper provides an overview of the construction techniques, the equipment, and the challenges associated with constructing 12? foot diameter shafts on this very complex project in one of the nation?s nicest landscape setting.

Jan 1, 2011

By Richard Crockford

The World Trade Center (WTC) is located on the west side of Manhattan in New York City, approximately 0.5 miles north of Wall Street, and is owned and operated by the Port Authority of New York and New Jersey (PA). As part of the WTC site redevelopment the New York City Transit Authority?s No. 1 subway line which runs through the site below grade, was underpinned so that the soil beneath it could be removed along with the rest of the new east basement excavation. Consequently a scheme comprising micropile installation through and around the existing subway box was designed. The subway had to remain in use throughout save for planned weekend outages to allow a portion of the underpinning to be fitted through or on to the existing structure. At times this involved accessing and drilling from within the subway tunnel under short General Order (GO) Subway shutdown periods. At either end of the subway passage through the WTC site jet grout underpinning was designed to provide support and to complete the excavation and construction of the east basement wall in the areas beneath the subway where it was impossible to install a slurry wall. The jet grout blocks thus formed had to be largely installed around the clock during 53 hour long GO weekend outages and had to overcome severe logistical constraints in and over the tunnel. The jet grout blocks had to provide strengths of at least 500 psi at 3 days and 700 psi at 28 days. The jet grouted soil mass also had to have a level of permeability less than 0.03 feet/day (1 x 10-7 m/s). After an extensive trial program and then production testing it was concluded that the glacial till above the rock proved to be a particularly difficult soil strata to collect test data from and hence the level of observational monitoring was increased to progress the excavation works. Throughout the installation of micropiles and jet grout columns extensive monitoring was in place and prompted a variety of working method changes. The work described in this paper was performed by the Nicholson Construction Company/EE Cruz Joint Venture.

Jan 1, 2008

By Alan D. Fisher

Amtrak made a decision to replace an aging bascule bridge with a vertical lift bridge for their crossing of the Thames River in New London, Connecticut. The new lift bridge occupies the same alignment and shares the same foundations as the bascule span. During construction the deep foundation caisson supporting the bascule span settled and tilted. Investigation into possible reasons revealed interesting historical facts, both of the construction of the innovative open well caisson foundations and of the state-of-the-art in tremie concrete placing methods in use at the turn of the century. This paper describes both of these topics.

Jan 1, 2008

By Michael Quadagno

Hudson River Pier 86, home of the historic USS Intrepid Aircraft Carrier and the Intrepid Sea-Air-Space Museum, is currently undergoing a $30M reconstruction. This project involves the demolition of the old timber pile supported pier and construction of a new 150 ft wide by 782 ft long concrete pier, built over the footprint of the old piles. The new pier consists of steel pipe piles, precast concrete pile caps, and a composite deck, made up of precast, prestressed concrete planks and cast-in-place concrete topping. This paper focuses on both the structural design and construction of the new pier, with emphasis on the pile foundation. Pier 86 is unique in that it is required to resist the extremely high lateral loads imposed on it by the permanently moored 898 ft long aircraft carrier during severe storms. A total of 360 steel pipe piles support the new pier. These piles, which are 24 in. in diameter and range in length from 58 ft to 175 ft, were driven down to bedrock. The piles, each having 200 ton allowable capacities, work together to resist the significantly large lateral loads exerted on the pier by the ship. The installation of the piles was unique in that all the piles, including the ?super-longs?, were fabricated to-length offsite, delivered to the site via truck and barge, and installed in one piece, eliminating the need for field splicing. The Pier 86 reconstruction will be completed within an extremely aggressive 18 month schedule, from January 2007 through June 2008. The refurbished aircraft carrier Intrepid will return home in September 2008, and the grand re-opening of the pier will be on Veteran?s Day 2008. This paper provides a case history for owners, government agencies, engineers, and construction professionals that will be faced with the challenges of designing and building new piers.

Jan 1, 2008

By Richard Pizzi

Built in 1806, Boston's African Meeting House is the oldest surviving Black church building in the country. A $7 million dollar renovation was begun in 2006 to restore this historic building to its 1855 appearance and to modernize the building's accessibility, electrical and mechanical systems. As part of the restoration, an underground utility room and elevator tower, needed to provide handicap access to the Meeting House, were constructed. Extending up to 17 feet below the foundations of the abutting buildings, the utility room was constructed within one foot of some of Boston's oldest and most expensive residences. All equipment and materials had to enter the work area through a narrow alley rendering conventional methods of excavation and construction of earth support using heavy equipment unfeasible. A unique combination of micropiles, structural cap beam, internal struts and shotcrete facing was designed and constructed to provide the permanent and temporary support of the lateral loads from the earth pressures and adjacent building surcharges and the vertical loads from the elevator tower. The narrow and congested streets of the Beacon Hill neighborhood presented many day-to-day challenges for the contractor.

Jan 1, 2011

By Jay L. Hodkinson

Replacement of an aging twin span river crossing in Vermont required a temporary bridge to accommodate traffic during construction. Soils beneath the temporary approach embankment consisted of very soft organic clayey silt underlain by interbedded, loose alluvial fine sand and silt/clayey silt. Reinforcement was required for the southern temporary approach embankment to limit settlement and to increase global stability factors of safety. A ground improvement design was developed using Rammed Aggregate Pier® reinforcement and was included in the contract documents as an FHWA Category II Experimental Feature. Instrumentation intended to document the performance of the supported embankment was installed. Piers were then constructed and monitoring commenced as embankment and bridge construction occurred. Weekly instrumentation data reports indicated continuing excess pore water pressure, settlement, and lateral deformation of the subgrade soils as the embankment and temporary bridge abutment was constructed. In response to the unanticipated monitoring results, further investigation indicated that significant deviations from the conditions and basis upon which the ground support design was developed were made during construction. This paper discusses these deviations and their specific impacts to embankment support performance, how these deviations occurred, the role that the ground support system played in maintaining global stability, measures taken to limit further detrimental impacts to the embankment, and provides recommendations for contract document preparation and construction oversight to prevent similar situations from occurring on future projects.

Jan 1, 2011

By J. Osterberg

A new device has been developed for load testing driven piles and drilled shafts which consists of an hydraulic jack or bellows which has a telltale rod fastended to the bottom. The rod extends upward to the surface through a pressure pipe. When pressure is applied, the jack or bellows expands, applying an equal upward and downward load at the bottom. The downward movement at the bottom is indicated by the rod and the upward movement is indicated by the movement at the top. Thus, upward and downward load-deflection curves can be drawn. As load increases, failure will occur either in end bearing or friction. Results of field installations are described. Total loads of up to 1,100 tons metric have been used. The method obviates the need for the reaction load required for the conventional pile loading test and separates friction and end bearing. It is especially advantageous for use over water, in crowded spaces and for inclined piles.

Jan 1, 1989

By D. Kolymbas

A simple formula is introduced which allows the evaluation of dynamic pile tests. The following case is considered: The pile top is dynamically loaded by an impact. The velocity v of the pile top is recorded over the time. Let v1 and v2 be the first and the second maximum of this curve. Then, the pile bearing capacity (resulting from ideally plastic resistance at the pile wall and at the tip) can be set approximately equal to Z(v1- ½ v2), where Z is the impedance of the pile cross section. Due to the assumption of ideal plastic resistances, radiation damping needs not be taken into account. Material damping may be important in rate sensitive soils (such as clay, even if it is highly overconsolidated). A simple correction procedure for material damping is proposed.

Jan 1, 1989

By R. T. Stain

Dynamic methods of load testing piles using a drop hammer to generate the input force have been in use for many years. These systems are based on the wave equations developed at the Case Institute of Technology, Cleveland, Ohio in the late 1960's and are well documented. Such tests are generally restricted to preformed driven piles, the driving hammer being a convenient means of generating large input forces. In 1979 the CEBTP (France) was sponsored by the FNTP (Fédération Nationale des Travaux Publics) to undertake research into existing classical methods and to develop a test that would be equally applicable to bored cast in place piles. The result of this research programme is a methodology known as SIMBAT, and which was included in a series of class A prediction trials in Belgium in 1987 (Refs 1 & 2, Paquet 1987, 1988). The purpose of this paper is: a) to examine the type of 'dynamic'/'static? load test correlations that can be obtained. b) to highlight the differences between the classical' methods and the 'SIMBAT' technique.

Jan 1, 1989

By Susheel R. Kolwalkar

A significant increase in the side shear capacity over a period of time is often observed in case of driven piles. This phenomenon is referred to as ?setup? or ?freeze?. This phenomenon cannot be predicted based on the knowledge of the engineering properties of soil. Different kinds of mechanisms have been proposed in order to explain set-up in cohesive soils. In engineering practice, set-up is incorporated in design on the basis of empirical formulae and depends to a large extent on personal experience and judgment of the design engineer. Set-up is a natural process which cannot be accelerated by any existing practice. A research was initiated to investigate the mechanism of pile set-up in clayey soils and explore the possibility of accelerating the set-up process by an electro-kinetic method. The system chosen for the present study consists of a prototype steel pile driven in kaolinite clay. A laboratory test program was developed at Cleveland State University in order to meet the goals of the proposed research. Results obtained from these tests are very encouraging and show pile capacity increase of 200% within the first 5 days of electric gradient application versus those that experience natural set-up. In this paper, theoretical considerations and laboratory test results are presented and discussed.

Jan 1, 2008

By M. D. Khattar

The paper describes the salient construction features of the Pile foundation work for the Railway viaducts in Algeria. Six viaducts were constructed for execution of the Railway line between Aintemouchent and Benisaf in Algeria. The work was executed by the Indian Railway Construction Company Limited of India (IRCON) for the Algerian National Railways (S.N.T.F.). These six viaducts had multiple spans of 36M resting on hollow piers of heights upto 69M. Most of the piers were founded on piles of 1 and 1.2M dia bored piles going upto 22M deep through cal­careous rocks and were designed for Railway loading in seismically active area. The work involved 356 piles & constituted a very important aspect of the whole work. The concrete in the piles was made with sulphate resistant cement and the integrity of the concrete was tested with Sonic method so as to ensure the quality. The piles were driven with the help of a hydraulic oscillator and the concrete was laid with a tremie pipe. Problems as encountered during execution have been explained.

Jan 1, 1989

By M. J. Preim

Two case histories are presented on the evaluation of static bearing capacity of piles driven in soils that exhibit time dependent strength changes. Under consideration are a steel and a concrete pile driven into soils generally consisting of silty and clayey fine sand. Pile dynamic measurements and analyses were performed on both piles during initial installation, and also during restrike one week later. This information was used to predict each pile's long term capacity (defined as 14 days after initial drive), which was then compared to that measured with a static load test. Agreement between predicted and measured capacities were remarkably good, with an average error of only 4.5 percent. Two weeks after driving, total pile capacities were three times those at the end of drive. If only the skin friction was considered, however, it increased by an average factor of 16. The increase in pile capacity was determined to be linear over the time period considered.

Jan 1, 1989

By L. F. Albert

The paper describes solutions given to foundation problems during the reconstruction of a power plant set on fire, located adjacent to several still Working Units. After a detailed site and laboratory investigation, it was decided that it could be possible to include within the new foundations the preexisting cast in situ driven piles with enlarged base 50 cm in diameter and let them work with new 41 cm driven, cast in situ piles without enlarged base. Demolition of existing caps was carried out with expansive mortar in order to avoid any possible damage to piles, whose actual conditions were checked by several load tests. New piles were designed to support service load by shaft resistance, in order to limit total and differential settlement. When piles had to be driven adjacent to nearby structures, measurements of peak soil particles velocity were carried out while driving piles at decreasing distance from critical locations. By preboring most of the upper clay layer it was possible to reduce within safe limits for structures the induced vibrations.

Jan 1, 1989

The process of pile driving disturbs the soil around the pile. The nature and magnitude of disturbance depends upon 1) the pile size, and 2) the nature of soil. Therefore, the prediction of a single pile behavior based on soil properties of undisturbed soil samples may not match its performance. Under lateral loads, the pile may loose contact with the soil near the ground surface especially in clays. The soil pile interactions are influenced the most by pile behavior in this zone. This situation further affects the tally of prediction and performance. Piles are used in groups. The zones of overlapping stress from one pile to the other both around the pile and below their tip particularly in soft soils, contribute to group effects. Empirical solutions have been developed for prediction of the pile group behavior. The group action is more involved under vibrations. Several cases of single piles and pile groups under static and dynamic loads from published records have been analysed. It has been shown that single pile test is the best source of information on the soil-pile-soil interaction effects.

Jan 1, 1989

By J. A. Elliot

Deep Mix-in-Place soil stabilisation is achieved by forming columns of soil/cement arranged to overlap by secant intersection. Alternate columns are constructed initially and infilled. The cementitious material injected is designed to retard the strength of the resulting mix thereby allowing satisfactory overlapping. Columns are constructed using a designed large diameter mixing auger mounted on a smaller diameter auger stem. This is firstly screwed to the design depth removing only such spoil as to enable penetration of the auger, and subsequently counter rotated and extracted in a predetermined mixing pattern and grout injection rate to ensure continuous and homogeneous treatment through each successive level. The process is performed whilst monitoring auger depth, grout flow and pressure. Cementation Piling and Foundations Limited used this technique to stabilise allu­vium and to facilitate the construction, by conventional techniques, of a circular pumping station pit of 10M diameter to 10M below ground level. The work was carried out within 3M of adjacent domestic properties, and on a very restricted site in Elland, West Yorkshire. Ground conditions consist of 2M of cohesive alluvium becoming water bearing and increasingly sandy and gravelly with cobbles which overlies the mudstones at 10.0m depth. Sandstones beneath formed an aquiclude to artesian ground water with the underside of the open excavation approxi­mately 1.0M from the top of this material. Peripheral treatment into the mudstone, coupled with pressure relief wells, proved successful and final excavation depth was achieved in "the dry".

Jan 1, 1989

By P. J. Yttrup

Small diameter timber piles are used in Australia to solve foundation problems in soft or filled ground and expansive soil. The paper describes the results of pile load tests to develop simple methods for bearing capacity determination and observation of the performance of piles in expansive soil.

Jan 1, 1989