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By John Vickers, William H. Hover, Paul C. Schmall

"Any sudden subsurface issue that threatens the stability of existing buildings or infrastructure is cause for immediate investigation and prompt remedial action. Nowhere is this more true than the nation’s dams and levees. A breach of any kind, no matter how small initially, has the potential to be catastrophic and impact a wide downstream area. Addressing the problem quickly and effectively is therefore critical. When a turbid water discharge developed from a rock drainage embankment at the toe of the earthen dam impounding Cannonsville Reservoir, near Deposit, NY, the source of the problem was quickly identified as resulting from an artesian water release from an underlying permeable silty sand and gravel formation during drilling of three exploratory boreholes in preparation for construction of a hydroelectric plant at the downstream toe area of the dam facility. Work was halted, intense 24-hour monitoring was implemented, and as a risk reduction measure NYCDEP began to draw down the reservoir’s total storage at a rate of a billion gallons per day. Input sought from contractors within the geotechnical community helped result in the design and development of a deep well system to control the artesian pressure. Once this primary objective was accomplished, modified compaction grouting was performed at the borehole locations to densify loosened soils, fill any voids created by the discharge activity, and seal off the permeable aquifer. This paper discusses the dewatering program, specialized drilling techniques required, monitoring and verification of pressures within the dam, and the grouting program.BackgroundCannonsville Dam, owned and operated by the New York City Department of Environmental Protection (NYCDEP), is located in Deposit, New York on the West Branch of the Delaware River and impounds the Cannonsville Reservoir. Built between 1959 and 1964, the dam has an impervious central and upstream core zone keyed into the glacial till foundation, a semi-pervious downstream embankment zone, and a rockfill toe and is approximately 2,800 ft (853.4 m) long and 175 ft (53.3 m) high. The dam is formed by two embankment sections. The left section forms the main embankment blocking the main river channel, while the right section is constructed over a topographic saddle or low ridge. Reservoir level is actively influenced by withdrawals through the West Delaware Tunnel, based on water supply need. Under normal circumstances, water is continuously discharged downstream to the Delaware River."

Jan 1, 2016

By Kyle R. Lackner, Jared P. Williams

"The Sutter Butte Flood Control Agency initiated the Feather River West Levee (FRWL) Program in 2010 to bring 35 miles of levee along the Feather River into compliance with applicable Federal and State standards for levees protecting urban areas. A combination of soil-bentonite cutoff walls, soil-cement-bentonite cutoff walls, and seepage berms will reduce flood risk by correcting under and through seepage deficiencies and remove more than 34,000 properties from the FEMA Special Flood Hazard Areas. The FRWL program includes a combined total of 7,744,803 square feet (SF) of cutoff wall planned to be constructed between 2013 and 2015. Cutoff wall construction methods to meet the design depths included conventional excavation to a depth of 85 feet and deep soil mixing for depths up to 120 feet. A key component of the FRWL program was the development of site specific mix designs using the design boring logs to evaluate the expected backfill gradation and permeability results. Issues that required a partnership between Contractors, Owner and Engineers included substantial Archaeological and Cultural Resource delays, significant depth changes due to a change in competent key, right of way acquisitions for abutting land, and the magnitude of the project in a resource limited industry.IntroductionThe Feather River watershed basin is located 50 miles north of Sacramento, CA and incorporates the agriculture producing communities of Yuba City, Live Oak, Gridley and Biggs. These communities are protected from flooding by levees that contain under-seepage and through-seepage deficiencies and were the cause of major failures in 1955, 1986 and 1997. The Feather River West Levee (FRWL) program was initiated by the Sutter Butte Flood Control Agency (SBFCA) in 2010. The long term objective of SBFCA is to correct the levee deficiencies and provide 200 year flood protection to more than 34,000 at risk properties located within the FEMA Special Flood Hazard Areas.Although FRWL contained a variety of construction components such as earthwork and pipe replacement, the slurry cutoff wall is the primary construction element for addressing under and through seepage deficiencies. From 2013 to 2015 approximately 6,649,210 SF of cutoff wall were installed using conventional excavation and deep soil mixing (DSM) techniques leaving 1,095,593 SF to be completed in 2016. The work was designed, solicited and constructed under two separate contracts, titled Project Area C and Project Area B&D. A summary of the contracts and cutoff wall quantities is presented in Table 1."

Jan 1, 2016

By David Guy, John Stanbury, Gilbert Tallard

"In 2009, storm surge from Hurricane Sandy inundated the Bay Park Sewage Treatment Plant located at El. +4 to +12 (+1.2 to +3.6 m) in East Rockaway, Long Island, NY. With all systems down, raw sewage water mixed in the floodwaters. A recurrence of such an event being unacceptable, and in view of rising future sea levels, a flood protection project was developed by Nassau County with funding coming in large part from the federally funded Sandy Rescue Fund. Designed by Arcadis/Hazen & Sawyer Engineers J.V., the protection took the form of a perimeter barrier capable of withstanding future storm surge. Due to limitations imposed by property lines and existing facilities, a levee design with three different types of cross section was developed to adapt to each location, adding construction complexity. The Long Island subsurface is characterized by beach sand extending to great depth. The clay required for the core and levee cover therefore had to be brought in from out of state. A thin silty clay layer at El. -23 to -25 (-7.0 to -7.6 m) served as an aquitard. The under-seepage was reduced by a hanging cut-off wall designed as a vibrated beam thin wall and filled with a salt water resistant, low permeability, self-hardening slurry.INTRODUCTIONOn October 29, 2009, Hurricane Sandy hit New York City, with a devastating effect on the region. The low lying Bay Park Sewage Treatment Plant (STP) (Fig. 1) serving Nassau County on Long Island was submerged (Fig. 2). All basements and underground mechanical facilities were flooded (Fig. 3) and millions gallons of effluent were released into the waters of the nearby Hewlett Bay which connects via other small waterways to the Atlantic Ocean."

Jan 1, 2016

By Abid O. Adekunte, David Greentree, David Hilton

"The construction industry is witnessing an upsurge in demand by property developers to have basements incorporated into their residential and commercial development schemes. This is attributable to perceived improvement to aesthetic and commercial values of buildings by underground space, amongst property owners. This trend is compelling more owners of buildings with no basements to explore the possibility of creating underground additional space beneath their existing buildings. The creation of a basement beneath an existing building entails the installation of a reinforced concrete (RC) underpinning system, temporary works, bulk excavation to basement formation level and construction of the basement structure, with associated aesthetic finishes.The L-shaped segmental RC underpins are a common system of choice for such underpinning works. They are multi-functional; providing vertical support to the existing superstructure, providing lateral support to earth and groundwater, supporting temporary and permanent surcharge loads from adjacent structures and services, whilst also forming part of the basement slab. This paper focuses on the first function of the Lshaped RC underpins; capacity under vertical compressive loading from the superstructure. The most common industry approach for the prediction of vertical capacities of L-shaped underpins is the oldfashioned Meyerhof’s (1953, 1963) effective width method, which is based on the traditional bearing capacity theory, whilst accounting for correction factors for eccentricity and foundation depth.The traditional bearing capacity formula is surrounded by a significant degree of uncertainty; estimates are highly user-dependent, as capacity prediction is sensitive to the chosen angle of shearing resistance (?), while there are difficulties in accurately measuring the in-situ ??value of cohesionless soils. In addition, the effective width approach has been shown to be very conservative by many research workers. The segmental RC underpins presented in this paper have been designed with an alternative less conservative method, which involves the use of a recently proposed consistent work-hardening plasticity model calibrated with field-based tests on footings of various aspect ratios and relative embedment in sand. The paper highlights the principles behind underpinning works for urban basement construction, the design of L-shaped RC underpins with the recently proposed plasticity model and the advantages of the method over traditional bearing capacity solutions and pre-existing plasticity models."

Jan 1, 2016

By Kamil Nuzha, Jianchao Li, Bashar S. Qubain

"The Philadelphia Water Department is rehabilitating Belmont Raw Water Basin. As part of this work, a 500-ft long, temporary cofferdam was designed to retain 35 ft of combined water and soil at the western half during the reconstruction of the eastern half. A cofferdam that comprises two integral rows of sheet piles was selected to take advantage of the soil’s weight between the sheet piles for increased stability. To fine tune the design, a geotechnical investigation was carried out to verify the subsurface conditions and, in particular, the top of rock variations along the centerline of the cofferdam. A detailed finite element analysis was performed based on the subsurface findings and incorporating the construction sequence to evaluate the behavior of the cofferdam at the following stages: installation of tie rods to connect to the two rows of sheet piles; partial excavation and installation of tiebacks; complete excavation of the east basin, and demolition of the cofferdam. Inclinometers and survey markers were installed every 100 ft along the cofferdam and were monitored throughout construction. The deformation measurements were in good agreement with the finite element results.INTRODUCTIONThe Philadelphia Water Department (PWD) Belmont Raw Water Basin is located at the intersection of City Line and Belmont Avenues in Philadelphia, PA. The facility actually contains two raw water basins, east and west, separated by an earthen dividing dike. Water leakage at the bottom of the basins and through the dividing dike together with increasing demand for a larger storage capacity dictated the replacement of the wide earthen dike with new narrower concrete structure. The temporary cofferdam was designed for a two-year period to facilitate excavation support, water cutoff, removal of the existing earthen dike and replacing it with a new concrete dike. During this construction sequence, the water level in the west basin had to be maintained at or near its full capacity.Various excavation support systems were considered for this project prior to the selection of a double wall sheet pile cofferdam. Fig. 1 shows a plan view of the cofferdam and the new dividing dike. A typical cross section of the two structures is shown in Fig. 2. Double row sheet pile walls are commonly used as both temporary and permanent retaining systems in open water applications such as construction works, quaywalls, breakwaters and revetments for storing industrial waste as indicated by Ohori, et al. (1984), Ohori et al. (1988), and Khan, et al. (2001). There are many advantages to double row sheet pile systems as recognized by Ohori, et al. (1984; 1988): (1) It can be installed and removed in the presence of water easily and quickly; (2) it provides stability with small width to height ratio, utilizing the existing soils between the installed sheet pile rows; and (3) it serves well as a means for water cutoff. These advantages meet the specific project requirements."

Jan 1, 2016

By John P. Turner, Benjamin J. Turner

"Non-destructive testing and evaluation (NDT/NDE) methods have become standard tools as part of the post-construction quality assurance of drilled shaft foundations. In responding to anomalies, foundation designers, owners, and contractors face a number of choices, including: (i) acceptance of a shaft with known anomalies, (ii) further investigations of integrity (e.g., concrete coring), (iii) repair schemes, and (iv) reject and replace. To assist in selecting the best option, analyses are often performed that involve assessing the structural performance of reinforced concrete shafts that may include defective concrete or voids. Currently, the analytical tools for predicting the flexural strength and stiffness of drilled shafts with defective concrete located in discrete regions of the cross section are limited. This paper presents a robust moment-curvature analysis tool for drilled shafts based on the fiber-element discretization method. The tool allows for consideration of anomalous or defective concrete regions in the shape and location that they are believed to exist in the shaft while considering explicitly the nonlinear material behavior of the intact regions based on expected material properties. A case study is used to illustrate the practical application of the analysis to drilled shaft projects.INTRODUCTIONImperfections such as defective concrete or accidental eccentricity of reinforcing cages are an inherent part of the drilled shaft construction process that will occur occasionally even when construction best-practices are followed. Petek et al. (2002), O’Neill and Sarhan (2004), Poulos (2005), and others have described the effects that construction defects can have on the axial and lateral performance of drilled shafts. Our industry has seen rapid progress in recent years in the development and improvement of tools for detecting drilled shaft anomalies, such as gamma-gamma and crosshole-sonic logging, sonic-echo testing, thermal integrity profiling, and even visual inspection with invasive video cameras. Nonetheless, in most cases the wealth of data from these tests is used by foundation engineers to make a fairly “black or white” decision—should the defects be repaired, or should the shaft be rejected? A third option that is not typically considered is to directly analyze the section, including anomalies, and compare the reduced strength and/or ductility to the actual project demands. This option takes full advantage of the data collected during integrity testing, and may provide a justifiable means for avoiding further construction costs and delays, whether for repair or replacement."

Jan 1, 2016

By Christopher R. Harris

"Considerations are presented for developing and implementing self-hardening slurry mix designs to be utilized in barrier seepage walls. Slag-cement-cement-bentonite (SCCB) slurries are the primary focus, with some comparisons referenced to the more traditional Portland-based cement-bentonite (CB) slurries. Field and laboratory mixing methods are reviewed, including 1) single sack – single mixer method; 2) bentonite slurry mixer – cementitious addition mixer method; 3) bentonite mixer – grout mixer – CB blending mixer method. Major phenomena associated with the dynamics of barrier wall excavation, such as loss of water from the in-trench slurry and consolidation of in-trench slurry are discussed. Other topics touched upon include sand content effects, fluidizers utilized, and chemical contaminants. The role of higher bentonite to water ratio is reviewed, with demonstration of improvement of filtration properties, and an increase of water retention of the final consolidated product.IntroductionSelf-hardening slurry has been utilized to construct barrier seepage walls for many decades. This is essentially a single-step slurry excavation and backfill process whereby the trench-supporting fluid gains strength over a short period during installation and maintains or develops low hydraulic conductivity. The resulting curing slurry becomes the actual barrier wall as the resultant cement-augmented clay slurry now fulfills the dual purpose of both temporary trench stabilization and final cured-in-place product. This eliminates the requirement and expense of subsequent backfill/slurry displacement operations required in traditional barrier wall installations.Self-hardening slurries have been fabricated using a number of various clays, most commonly sodium bentonite, calcium bentonite, attapulgite, and sepiolite. Perhaps due to plentiful high quality sodium bentonite deposits found domestically, the proven excavation stabilization properties imparted from sodium bentonite slurries, sodium bentonites are typically specified for formulating self-hardening slurries in the US. Cementitious materials utilized most commonly are Portland cement and slag (ground blast furnace slag or GBFS). For the purposes of this discussion, self-hardening slurry having a cementitious of Portland will be referred to as CB. Those having cementitious material of GBFS replacing Portland (partially or wholly) will be referred to as SCCB."

Jan 1, 2016

By Glen M. Bellew, James F. Mehnert

"The Kansas City District-United States Army Corps of Engineers has completed the design modification of a pile supported floodwall located along the Missouri River in Kansas City, Kansas. This deep foundation supported floodwall protects over 2 billion dollars in infrastructure, is approximately 17 ft (5.2 m) tall and is 1,446 ft (440.7 m) long. Design modifications included the addition of a row of drilled shafts and the addition of relief wells. Typically, deep foundation design is controlled by total stress analysis and undrained soil strength. Neither controlled design at this site, where effective stress and drained strength controlled. During high river stages, artesian pressures develop, leading to a reduction in both effective stress and pile capacity. Deep foundation analysis software available to the designer does not allow these effective stress conditions to be directly entered, so a unique way was developed to account for them. A load test was performed to verify the design. During load testing, the supporting ground was unsaturated and had effective stress conditions different from those that controlled the design. A load test evaluation process involving unsaturated soil mechanics was developed and performed. This paper will share both the effective stress design process used and the load test interpretation process performed.INTRODUCTIONThe Fairfax-BPU Floodwall is part of the Fairfax-Jersey Creek Flood Protection Unit in Kansas City, Kansas. The floodwall was built in the 1940s and currently provides Missouri River flood protection for over 2 billion dollars of infrastructure in the Fairfax Industrial Area. The floodwall averages 17 ft (5.2 m) in height, is 1,446 ft (440.7 m) in length and is divided into 35 separate monoliths. The originally constructed foundation support for each of these monoliths typically consisted of three rows of seven tapered steel monotube piles, each roughly 20 ft (6.1 m) in length. All monontube piles are tipped in sand, well above bedrock."

Jan 1, 2016

By Thomas Billups, Brendan FitzPatrick, Doug LeDo, David Carchedi

"Working in urban environments presents unique logistical challenges beyond those typically associated with traditional geotechnical analysis and design. These challenges often include working on sites with limited access and laydown area, vibration concerns for adjacent structures and the need to work from variable elevations or within excavations. This paper describes the use of the modular Ductile Iron Pile system, a low-vibration driven micropile, on two urban projects on the Johnson & Wales University campus in Providence, Rhode Island. The paper describes the successful implementation of Ductile Iron Piles installed to develop capacity in end-bearing on one site and friction on the second site. Design, installation and quality control operations are all presented as well as the results of full-scale load testing performed on non-production test piles. This paper is of importance to the industry because it describes a versatile option for project teams as an alternative to traditional micropiles, helical piles or other deep foundation systems for urban sites.INTRODUCTIONWorking in urban environments presents unique logistical challenges beyond those typically associated with traditional geotechnical analysis and design. These challenges often include working on sites with limited access and laydown area, vibration concerns for adjacent structures and the need to work from variable elevations or within excavations. Two recent projects in downtown Providence, Rhode Island faced a combination of problematic soil conditions and urban construction challenges including vibration concerns. Both projects were a part of the Johnson and Wales University campus development. Figure 1 illustrates the urban locations of the sites."

Jan 1, 2016

By Jamey Rosen, Georgette Hlepas

"Bluestone Dam is a concrete gravity structure with an overall length of 2,060 feet and a maximum height of 165 feet above the streambed. Several major project modification designs have been implemented and additional modifications are currently in construction and design phases. Due to the various modifications since original construction was completed in 1948, detailed documentation with visualization of the project features is needed. A three-dimensional model of the internal and external features of Bluestone Dam was generated from LiDAR data, survey information, and other data sources. One of the key features of interest in this model is an accurate visualization of over 200 dam anchors based on downhole anchor surveys. The model is accessible in Microstation and Geographic Information Systems (GIS), allowing users to rotate the anchors in three dimensions; view them in the context of geology, internal dam structural features, historical construction records, site photographs, bathymetric data, and instrumentation data. Users can “click” on individual anchors to view associated construction details and open a comprehensive installation packages. The model will be used by the United States Army Corps of Engineers (USACE) as part of a larger Geospatial Data Management System as a historical accounting of the project construction data, and be a long-term living document for use by both design engineers and operations staff to assess dam safety risk and to design future project modifications.IntroductionDuring the life of any project, critical data concerning the construction and performance history are required to be collected and maintained. The data collected prior, during, and post-project construction help with the design process, ensure that the project is built to specifications and is performing as per design intent. During the Post-Implementation Evaluation (an evaluation performed after a major project modification), these data are used to visualize the repairs, verify the construction was performed per design intent, and document the history of the construction phases, associated test results, and overall effect on the project. The project described in this paper is the construction of a system of tools to effectively use these data.Data collected and maintained during the operations phase helps to ensure that the project is continuing to perform as per design and aids in advance warning of any potential failure or required maintenance. Dam Safety, Emergency Management (EM), and Operations and Maintenance personnel can use the system to verify the status of the project in preparation for a high flood event. For example, if there is repair work being performed on a critical feature of the project that would affect the operation of the dam structure during a flood event, Operations personnel would be responsible to update the status of the system such that Dam Safety and EM would be able to identify the feature that is out of service, its date of expected repair completion, and the implications during a flood. In addition, risk assessments typically require a full history of the project and its performance. Any concerns that arise concerning the safety or performance of a project will require a full documented history of the project and its components. Proper documentation and data management are key in this assessment process."

Jan 1, 2016

By Behzad Khorshidi

"The ultimate objectives of the post-tensioned strands are to connect the precast segments into a ring and provide pre-stress in the tunnel circumference. The method involves inserting the strand through the preliminary embedded duct in the precast concrete segments and then tensioning the strand by jack and fastening it. The post-tensioned strand eliminates the necessity of bolt connections between the segments and may reduce the labor cost and increase speed of lining construction. Pre-stressing of the segmental lining reduces the steel reinforcement or fiber volume in precast segments and/or thickness of the precast segments which would result in reducing the manufacturing cost of them. Pre-stressing would reduce cracking and increase water tightness, and would provide smooth intrados due to eliminated bolt joints and pockets in the tunnel lining. Pre-stressing would increase resistance to internal pressures as well. Further, this system could work very well structurally in tunnels with squeezing rock or tunnels with high seismic loadings. INTRODUCTION OF THE METHODPost-tensioning is commonly used in the construction of bridges, large buildings, nuclear power stations, and water tanks but its utilization in tunnels is still in its infancy.The precast pre-stressed concrete segmental lining can be used for shield tunnels. It provides a reinforced lining ring by the following construction stages and as shown in Figure 1:1) Segments to be assembled by TBM to complete a full ring2) Steel strand to be inserted through embedded duct (sheath) within the segments3) The strand to be tensioned by Jack after anchorage of the other end4) The strand to be fastened after reaching required tension load5) The horizontal strands (if necessary) to be installed, tensioned and fastened6) The recesses and gap between strand and duct to be filled by groutingFurther, Figure 2 shows an unbonded post-tensioning strand model; Figure 3 shows an anchor sample (Xanchor); Figure 4 shows a duct (sheath) and anchor within reinforcement; Figure 5 depicts the posttensioning of a strand by jack; and Figure 6 is an image of the Midorigaoka Trunk line tunnel in Sagamihara, Japan which was constructed using this system."

Jan 1, 2016

By Aditya Ayithi, William G. Ryan, Dean Herbst

"For rock socketed drilled shafts, it is a common practice not to include the frictional resistance of overburden soils into the nominal capacity estimation. The primary reason often being cited is “overburden soils resistance is negligible compared to that of rock socket resistance.” However, in certain geological conditions, where the rock layer is located at greater depths, friction resistance from overburden layers can be significant. In addition, at such great depths, shaft drilling becomes very complicated and expensive. In these situations, considering the resistance of the overburden layers can be an economic alternative.This paper presents a case study of an Osterberg cell (O-cell) load test conducted on a 161.8 feet long and 78-inch diameter instrumented test shaft. Based on initial designs, a 72-inch diameter rock socket of lengths 23 and 26 feet was required to provide a LRFD factored friction resistance of 3,200 kips. The load test results revealed that the material in the 72-inch diameter socket does not represent a true rock. However, the test results also proved that the factored friction resistance of overburden layers is greater than the required design resistance. Based on the load test results, it was decided to allow the overburden soils frictional resistance to be considered in the shaft design, resulting in significant economic savings.INTRODUCTIONRock socketed drill shaft design guidelines of various State Department of Transportation (DOTs) agencies allow friction and/or end bearing resistance of only the rock socket portion into the design capacity estimation. It is typical to neglect the frictional resistance of overburden soils. However, in certain geological conditions where the rock layer is at greater depths, friction resistance of the overburden soils can be significant. In this case the friction resistance of overburden soils was verified via the specified instrumented O-cell test program and then used as part of the design capacity.PROJECT DESCRIPTIONAs part of I-29 improvement project, Iowa Department of Transportation (Iowa DOT) planned to replace the dual four lane bridges that cross the Floyd River in Sioux City, Iowa with dual six lane bridges (Fig. 1). Expected benefits from this improvement include improved safety, traffic operations and roadway infrastructure conditions.BRIDGE SUBSTRUCTUREThe project consists of two individual bridges; a new south bound bridge and a new north bound bridge. The south bound bridge is 646-ft long and the north bound bridge is 644-ft long. Both are six-span, pretensioned and pre-stressed concrete beam bridges of varying width. Bridge foundations were designed such that the abutments of both bridges will be supported on driven steel piles and the bridge piers will be on drilled shaft foundations."

Jan 1, 2016

By M. Raffaldi, J. Johnson, M. Stepan, D. Benton

"The Office of Mine Safety and Health Research (OMSHR), Spokane Mining Research Division (SMRD), is continuing its High-Energy High-Displacement (HEHD) testing of field-scale shotcrete panels. A test program was developed to determine the relationship between applied force, displacement, and energy for both unreinforced and reinforced shotcrete panels. Reinforcement options consisted of synthetic macro-fibers, sprayed polyurea liners, chain-link fence, welded-wire mesh, and combinations of these products. During testing, photogrammetry was used to measure the geometric changes of the panels, including volume changes and panel cracking. These measurements were correlated with the load and displacement data, allowing visual observation to be related to the applied force and displacement. The test results provide a comparison of the mechanical performance of the various panel types and can be used by the practicing engineer to evaluate installed support based on visual observation of cracking and deformation. Visual assessment of the loading cycle and strength capacity of shotcrete in underground excavations will improve mine safety by providing a means to quantify the stability of installed shotcrete support. INTRODUCTION The National Institute for Occupational Safety and Health (NIOSH), Office of Mine Safety and Health Research (OMSHR), Spokane Mining Research Division (SMRD) is continuing research on the behavior of shotcrete when used as the surface support component in mining ground support systems. Ground control safety often depends on supporting, or at least containing, the ground between the rockbolts. Shotcrete and mesh, in various combinations and with other components, are often used to accomplish this (Figure 1). Maintaining support pressure during ground deformation is key to the performance of these systems, and to ensuring miner safety. However, the toughness of a ground support system–the ability to maintain strength over large deformations–is difficult to quantify. Researchers at SMRD have responded to this deficiency by designing a full-scale test device, described previously by Martin et al. [2015a], and beginning a testing program to assess the behavior of shotcrete surface support reinforced with a variety of products including: fibers, chain-link mesh, welded-wire mesh, spray-on polyurea liners, and combinations of these products. This paper presents the findings of these tests."

Jan 1, 2016

By M. D. Riegel, P. B. Pizzimenti, E. M. Zamiskie, Britain A. Materek

"The Skanska/Kiewit/ECCO III team (SKE) in association with HNTB was awarded the design-build contract for Phase I of the Kosciuszko Bridge Replacement Project. As lead designer for the SKE team, HNTB was responsible for the design of the Brooklyn Connector which includes construction of approximately 2000 feet of new staged earth-filled embankments utilizing prefabricated modular retaining walls (T-Walls®). The proposed embankments will be constructed adjacent to and beneath the existing Brooklyn Queens Expressway (BQE) viaduct while the existing viaduct remains in service. Critical aspects of the settlement assessment relating to the soils supporting the existing BQE will be addressed, as their behavior drives the deformation of the viaduct. Furthermore, a construction monitoring program was used to enable the designer to assess settlement predictions and allow SKE to mitigate potential impacts to the existing BQE during construction. Additionally, the methodology for installation of the embankments in a limited access area underneath an active viaduct supported on settlement sensitive shallow foundations will be presented.INTRODUCTIONSkanska-Kiewit-ECCO III Joint Venture, in association with HNTB was contracted by the New York State Department of Transportation (NYSDOT) to design and construct the Phase 1 replacement of the Kosciuszko Bridge Design-Build Project. Phase 1 of the project involves the design and construction of the new eastbound structures of Interstate 278 over Newtown Creek from Brooklyn to Queens. The project runs between Morgan Avenue in Brooklyn and the Long Island Expressway Interchange in Queens (approx. 1.1 miles) and includes the staged demolition of the existing structures."

Jan 1, 2016

By V. A. Sernov

"One of the ways to increase the bearing capacity of a piled foundation is to take into account soil resistance in the base of the raft. Piled raft is similar to shallow foundation and can transfer significant part of the load into the base. It allows reducing number of piles in the foundation or shortening their length. As a result building terms and foundation costs reduce considerably. However, nowadays in Belarus there is no reliable and suitable in design practice methods of calculation of piled-raft foundations. In order to devise such methods we have analyzed the results of piled foundation tests fulfilled by various authors up to date and have carried out series of field and laboratory investigations in Minsk. The most important results of the investigations are provided in the article. Methods of analysis of piled-raft foundations are described.INTRODUCTIONPile foundations of late years are used extensively in connection with the increased number of storeys and load increment on the soil. Often pile foundations are applied in comparative favorable ground conditions at the surface of the base. In such cases the increase of the bearing capacity of foundations and the reduction of construction cost are questions of primary importance for designers. One of the ways to increase the bearing capacity of a piled foundation is to take into account soil resistance in the base of the raft. Piled raft is similar to shallow foundation and can transfer significant part of the load into the base. It allows reducing number of piles in the foundation or shortening their length. As a result, building terms and foundation costs are reduced considerably. However, nowadays there is no reliable and suitable in design practice methods of calculation pile foundations with bearing rafts. In order to devise such methods we have analyzed the results of piled foundation tests fulfilled by various authors up to date and have carried out series of laboratory and field investigations.Long before the constitution of the first piled-raft foundations in the Soviet Union there were attempts to consider soil resistance in the basis of isolated and strip grillages. Such bases can be considered as separate fragments of the piled-raft foundation. Prof. A. A. Bartolomey had tested more than 70 pile foundations of natural size in different ground conditions. The length of piles was 3 12 m (?????????? 1995). The observed results show that the raft carries about 10 12% of the total load applied when length of piles is over 9 m and space between piles is a=3d. Bearing capacity of the raft is about 35 40% when the length of piles is 5 8 m and a=6d. Prof. Golubkov has tested 2 prismatic piles (cross section: 350x350 mm, L=3800 m) and 2 pyramidal piles (cross section: head - 600x600 mm, foot – 100x100 mm, L=3000 m). One of the piles was tested with a raft and the other one without a raft. Significant influence of the raft on total bearing capacity was determined, the more the settlement was the more it influenced on the raft. Bearing capacity of the raft was 27,5% in foundation with prismatic pile and 42% with pyramidal pile (???????? et al. 1971)."

Jan 1, 2016

By Karen J. Dawson, Francisco Johnson

"Pressure-grouted high strength helical displacement piles are a recently developed pile type that can be useful in conditions where noise or vibrations must be low or where access or clearance is limited. However, there is no information in the literature that can be used to estimate the soil resistance of these piles or production rates. To fill this information need, this paper presents a New Jersey installation case history and the results of static axial and lateral load tests on both pressure-grouted and ungrouted high strength helical piles at the case history site and trial installation locations in New Jersey and Washington State. Piles between 25 and 50 feet long comprised of steel shaft diameters of 4.5, 5.5, and 7 inches with equivalent grout column diameters ranging from 12 to 22 inches were tested. Lateral loads of up to 100 kips and axial compression loads of up to 700 kips were applied. The results of the load tests are compared to predictions of lateral deformation and axial resistance.INTRODUCTIONHelical piles have long been recognized as a useful foundation type in situations where noise and vibrations must be limited, or where there are access or clearance restrictions. Relatively well-documented design methods and torque to capacity correlations have been developed for the most commonly used helical piles, which are relatively small (typically shafts of 6 inches or less) with corresponding low load carrying resistance.With the increased need to construct in congested urban environments, there is incentive to develop helical piles with higher axial resistance. Seismic and other loading conditions also require lateral resistance, which is low for the typically small helical pile shafts. One method of increasing the soil resistance, both axially and laterally and at relatively low cost, is to place grout around the shaft. Injecting the grout under pressure through the hollow helical pipe section and out a grout port or ports located near the toe of the pile has the potential to increase the pile resistance significantly above that which can be achieve by gravity grouting. Not only does the pressurized grout push out against the surrounding soil, but the rotating helix helps to distribute the grout laterally. Unfortunately, little information is available in the literature to help designers estimate the resistance of grouted helical piles in general and none is available regarding pressuregrouted helical piles."

Jan 1, 2016

By A. Daugiala, D. Coleman

In 2014 the New York State Department of Transportation (NYSDOT) awarded a Design-Build contract to the joint venture team consisting of Skanska which is the managing partner; Kiewit Corporation and Ecco III (SKE) and HNTB as the lead design firm. The design build team employed methods to provide schedule savings and commercial benefits to the owner NYSDOT. This paper presents the design approach and construction methods used to accelerate drilled shaft installation supporting the main span foundation for the cable stayed bridge. The drilled foundation contractor Underpinning and Foundation Skanska, a division of Skanska was responsible for assisting with design, budgeting and construction of the drilled shaft foundation construction. As part of the Request for Proposal (RFP) bid process, Alternate Technical Concepts (ATC) was encouraged by the NYSDOT. The JV team proposed an ATC which involved a scaled production shaft testing method to simulate the ultimate load level, commonly referred to as the “Chicago Method” was used in the rock socket employing the Osterberg Cell (O-Cell) testing procedures. To the authors knowledge this was the first NYSDOT project where this approach was utilized on a Demonstration/Production installation to validate construction procedures and load bearing capacities. Construction procedures, challenges and solutions are discussed in detail. Upon completion of successful drilled shaft construction, concrete integrity is verified using two methods – Cross Hole Sonic Logging (CSL) and Thermal Integrity Profiling (TIP). A comparison from the contractor’s perspective is provided. Finally the drilled shaft rock socket is tested to ultimate end bearing values while rock socket side shear stresses are not exceeding the service level loading. Lateral load test was also a RFP requirement; the test arrangement and performance are discussed in detail as well. The Kosciuszko Bridge location poised unique geotechnical challenges on many levels shifting towards an extreme boundary of parameters encountered in New York City Area for drilled shaft construction. The JV team and specialty drilled shaft contractor actively participating in the shaft design and construction practice coordination and working with NYSDOT yielded a successful foundation solution which provided cost and schedule savings to the project.

Jan 1, 2016

By Kenneth E. Henn, David B. Paul, John D. Rice, Brian H. Greene

"Several laboratory modeling programs have been conducted to investigate the mechanisms associated with internal erosion of dam embankments and foundations. The investigation consists of developing laboratory devices to model three separate mechanisms associated with process: 1) contact erosion along bedrock joints, and 2) piping into an open bedrock defect. The contact erosion device subjects the soil above a bedrock joint to high velocity flows in the joint. The erosion into a bedrock defect device examines a number of static and transient hydraulic conditions to study the mechanisms associated with this type of erosion. Numerous tests have been conducted using both devices. The results of the modeling will be discussed along with a discussion of how this information could be used in future dam design and risk assessment studies.IntroductionA series of laboratory modeling programs were performed to assess the seepage and internal erosion behavior of several man-made and natural structures within dams and their foundations. Each model was performed on a “bench scale” and depicted an isolated location where internal erosion was likely to occur. The models were subjected to hydraulic boundary conditions to simulate the in-situ conditions so that the processes of internal erosion could be observed. Two laboratory devices were developed to model conditions depicting 1) contact erosion along a bedrock joint in contact with a dam embankment, and 2) backward erosion (piping) into an open bedrock defect (joint, solution void, etc.).Embankment dams often have rock foundations containing defects which may detrimentally impact future performance. Further, there are existing foundations which contain rock defects that may already be detrimentally impacting the dams; however, due to the inherent aspects of the mechanism, the signs of distress may not have propagated to the surface and thus not observed during inspections. A better understanding of the mechanisms which are influenced by, and impose their influence upon, rock defects will enhance the ability of dam safety professionals to analyze the risks associated with internal erosion due to rock defects, increase our ability to monitor and successfully initiate earlier detection, and also increase our ability to design remediation methods to contend with rock defect failure modes."

Jan 1, 2016

By Sven Schröer, Lilma Schimmel, Dimiter Alexiew

"The Geotextile Encased Columns (GEC) deep foundation system for embankments on soft soils was introduced some 20 years ago and is now considered State-of-the-art worldwide.The GECs consist of compacted granular fill, similar to common gravel columns, with one decisive difference: they are confined in a high-strength low-strain flexible geotextile “cylinder” (encasement). This engineered element provides a very efficient tool to control and optimize the behavior of the system. GECs perform very well even in extremely soft soils ensuring bearing capacity (stability) and reducing settlements. Due to the encasement, they a lso provide high lateral ductility. A wide range of fills including sands can be used.The remarkable reduction of vertical stresses in the soft soil surrounding the GECs results in a decrease of lateral pressure as well. Such reduction combined with the lateral ductility allow GECs to be also used for lateral pressure-relief adjacent to sensitive foundations, e.g. rigid piles. The application of GECs as lateral pressure relief was recently used in Brazil and Germany where bridge abutments were built on concrete reinforced-piles. The GECs below the bridge approaches and adjacent to the piles decreased the lateral pressure to acceptable values.This paper presents two case studies for which the most relevant parameters, the geotechnical conditions, specific problems, engineering philosophy, final solution and lessons learned are discussed. Furthermore, instrumentation programs were applied in both projects. The most important results in terms of displacements and stresses are shown, evaluated, summarized and commented upon, focusing on the lateral stress-relief, followed by conclusions and recommendations."

Jan 1, 2016

By M. D. Riegel, Brian T. Felber

"Construction of foundation elements in an urban environment is often complicated by multiple constraints such as existing foundations, utility conflicts, maintenance and protection of traffic on high volume roadways, low overhead clearances, and vibration and displacement monitoring to reduce risks of impact to existing facilities. Micropiles are commonly a preferred foundation alternative in an urban setting to mitigate some of these risks. This paper presents examples in which micropiles helped reduce risk in an urban setting on the two subject infrastructure improvement projects. The case studies presented include the Verrazano Narrows Bridge HOV and Bus Ramp Improvements in Brooklyn, NY and the Kosciuszko Bridge Replacement in Queens and Brooklyn, NY. The paper details the micropile design, how risks were mitigated, and the complications to each of these projects associated with the urban setting.INTRODUCTIONThe paper begins with background information about the Verrazano Narrows Bridge HOV and Bus Ramp Improvements Project, followed by background information for the Kosciuszko Bridge Replacement Project. This introductory background information is followed by discussion of the urban site constraints, which controlled the foundation type selection for both projects. In closing, the paper discusses the micropile design process, load testing, and construction.VERRAZANO NARROWS BRIDGE HOV & BUS RAMP IMPROVEMENTS BACKGROUNDProject ScopeThe project consists of two new ramps; one designated for HOV / Bus traffic between Staten Island and the Gowanus Expressway, and one to be utilized for storing the barrier transfer vehicle. Also included is the complete reconstruction of Ramps B and F to accommodate horizontal and vertical alignment clearances from the new ramps, removal of the median of the upper level to add one lane, utilities improvements, stormwater improvements, and miscellaneous structural repairs. The new HOV / Bus Ramp was designed for reversible traffic flow to accommodate the demand of the peak traffic direction by movable barrier.Geotechnical / Foundation Engineering ScopeThe geotechnical work included a desk study review of existing plans, geotechnical reports, and geologic maps. This data was subsequently supplemented with a subsurface exploration program. Once completed, foundation design was performed for 25 proposed bridge substructures. Four existing battered pilesupported foundations and two shallow foundations were evaluated for increased loading. Upon completion of the foundation design, foundation plans, specifications, and an engineer’s estimate were prepared. Foundation installation was observed on a part-time as needed basis."

Jan 1, 2016