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By Patrick J. Hannigan, Seth Robertson, Frank Rausche, Rozbeh B. Moghaddam

The Top-Loaded Bi-Directional Test (“TLBT”) and the conventional Bi-Directional Load Test (“BDLT”) are full-scale load tests where loads are applied bi-directionally to the foundation element. The BDLT uses an embedded loading source consisting of a jack assembly with one or multiple hydraulic jacks located between two steel bearing plates. As the jack(s) within the jack assembly is/are pressurized, the plates receive the load from the jack(s) and transfer these loads to the foundation element. In the case of the TLBT, the loads are also applied bi-directionally to the foundation element. However, in the TLBT case, the loading source is located above the foundation head. With the TLBT’s non-embedded and reusable load assembly, the loads are applied to the foundation using the steel shaft bearing and base bearing plates cast within the foundation. These plates are connected to the load assembly at the foundation head via Grade 75 or Grade 150, threaded, steel bars. This paper presents comparison results from a full-scale load test performed by both bi-directional load testing methods on adjacent test shafts. Details regarding subsurface conditions as well as test shaft construction and installation are included for the comparison tests. Test results and corresponding analyses are presented and discussed in detail.

Sep 8, 2021

By Patrick J. Hannigan, Frank Rausche, Rozbeh B. Moghaddam

The Top-Loaded Bi-Directional Test (“TLBT”) is a new method to apply bi-directional loads to a deep foundation element with the loading source located above the foundation head. In the TLBT reusable load assembly, loads are applied to the foundation using the R-System which consists of two stacked steel plates located at the geotechnical resistance balance point or at the foundation base connected to the load assembly via vertical elements. The top plate or the Shaft Bearing Plate (“SBP”) will transfer loads to the foundation upper portion, and the bottom plate or the Base Bearing Plate (“BBP”) will transfer loads to the foundation lower portion as well as the foundation base. At the surface, above the foundation head, a hydraulic jack is located between a Top Load Assembly (“TLA”), and the Bottom Load Assembly (“BLA”). The TLA and BLA are connected to vertical elements which are consequently connected to the R-system. As the jack is pressurized and expanded at the surface, the R-System plates are separated, and the foundation is bidirectionally loaded. This paper presents a brief description of the conventional Bi-Directional Load Test (“BDLT”) including benefits and limitations followed by the TLBT method introduction including its benefits and advantages over other testing methods.

Sep 8, 2021

By Andreas Andenæs, Arne Schram Simonsen

"AbstractThe Tresfjord bridge is with its variety in foundation concepts and difficult soil conditions one of the most geotechnically challenging projects in Norway at the time. The project comprises design of large concrete caissons, steel core piles through large rock fills, and closed end steel pipe piles in up to 40m water depth driven in very hard moraine. Test piling has also been conducted to check feasibility of the concept, and PDA measurements have been used to verify sufficient capacity of piles. FactsThe Tresfjord bridge is part of the new export road from Ålesund to Åndalsnes on the North-West coast of Norway built by the Norwegian Road Administration. The bridge will reduce travel time with about 30 min between the cities, see Figure 1. The bridge is planned to open summer 2015.The Bridge crosses the Tresfjord and will be 1290 m long. The bridge is built as a free cantilever bridge and will be resting on a total of 20 nos. of foundations, where two are abutments resting on steel core piles, three are casted directly on bed rock and 13 are foundations resting on steel pipe piles. The last two foundations holding the main span will be concrete caissons resting on bed rock and moraine. Figure 2 shows a 3D model of how the finished bridge will look. Multiconsult AS is responsible for design and pile supervision , while the Joint-Venture Bilfinger-Tresfjordbridge ANS is responsible contractor.Soil ConditionsPercussion soundings and sampling together with coring have been performed in the individual foundations using a small geotechnical equipped vessel. Acoustic and refraction seismic profiling have also been carried out to tie in the layers between the boreholes.The soil conditions are varying over the length, but are in general dominated by a soft top layer (2-4 m) of sediments over very hard moraine with occasionally large boulders. Piles in the two foundations closest to shore on the western side of the bridge are piled to bed rock with penetrations up to about 27 m in soil.Water depth varies from about 10 to 40 m for the piled foundations. Figure 3 show how the topography of the seabed varies over the bridges length."

Jan 1, 2014

By Maurizio Siepi, Paul van Horn, John Coupland, Julian Crawley

"TTMJ is the acronym for the Slurry (Diaphragm) Wall Tension Track Milled Joint currently in development as part of the European Union's innovative and far-reaching Horizon 2020 initiative (FTI Pilot-2015-1 720579). The TTMJ Project has been specifically set up to deliver this versatile new step-forward in Slurry Wall technology. The TTMJ System is protected by patent in Europe and the USA, and is currently under development by a consortium comprising Trevi SpA (Italy), Arup (Netherlands) and CCMJ Systems (UK). The principles of the TTMJ System together with the installation process are herein described in general terms. The system is still under development with field trials scheduled for early 2018, so some of the detail will not be disclosed at this stage. It is the intention of the Authors that the results of these field trials and a more complete description of the System will be presented in a paper we intend to submit for the DFI/EFFC International Conference on Deep Foundations and Ground Improvement to be held in Rome, Italy in June 2018. The final section of this paper explains how the TTMJ system can be applied to a common application of slurry wall construction; deep circular or multi-cell shafts. The system can be used to construct shafts more easily and at less cost than current methods. It also allows shafts with smaller internal dimensions to be constructed than is currently practical.INTRODUCTIONCCMJ Systems (UK) realised that an innovative new approach to forming joints in both Slurry (Diaphragm) Walls and Secant Pile Walls would provide greatly improved joint integrity to greater depths, to the overallbenefit of retaining wall quality, across the world-wide foundations industry.In particular this new system is designed to:??Increase the effective depth range of Slurry Walls (especially walls excavated by grab) and Secant Walls??Remove the requirement for Stop-ends or Joint Formers??Allow for a Shear Key at the joint??Allow for a Water Stop to be installed at the joint??Permit Continuous Reinforcement across the joint??Optimise Reinforcement Density and hence Concrete Flow??Facilitate joints in corner panels eliminating the need for “L” shaped cages and reducing largesingle-pour concrete volumes and slurry storage capacity requirements.??Enable the construction of smaller-dimensioned square and circular deep shafts (especially useful for city-centre sites) than is possible with current methods.CCMJ Systems approached other industry specialists with a view to forming a development team to explore the possibilities for this new technique."

Jan 1, 2017

By Athena C. Denivo, Pablo V. Lopez, Michael McMaster, Sissy Nikolaou, Alfred H. Brand

"The paper presents the history of development of the United States Tennis Association (USTA) site, focusing on geotechnical, geoseismic, and foundation engineering challenges associated with it. The site is located at the Flushing Meadows Corona Park area of Queens, New York. Now home to the Billie Jean King National Tennis Center (BJKNTC), the site used to be a biologically rich, tidal salt marsh that extended south from Flushing Bay and overlaid an ancient buried valley. In early 20th century, Brooklyn Ash Co. was contracted to fill the marshland with cinders and furnace ashes. F. Scott Fitzgerald describes the “Valley of Ashes” as “a fantastic farm where ashes grow like wheat into ridges and hills and grotesque gardens; where ashes take the forms of houses and chimneys and rising smoke, and finally, with a transcendent effort, of ash-gray men who move dimly and already crumbling through the powdery air.” In 1939 the site was leveled and filled to host the World’s Fair and refilled again for the 1964 World’s Fair.The USTA moved to the site in 1978 and in mid-1990’s constructed the 23,000-seat Arthur Ashe Stadium (AAS). Currently, USTA has a Strategic Vision Plan venue with several interconnected construction projects including buildings, infrastructure upgrades and improvements to site circulation. In addition to a historical walkthrough, the authors will discuss technical challenges of supporting these developments through layers of fill, thick organic silty plastic clays and regional varved soils with bedrock found 300 to 400 feet deep. The subsurface is not only a weak foundation medium, but is susceptible to large amplification of seismic waves propagating from the bedrock during earthquakes. The developments are usually founded on project-specific pile foundations that carry static loads in deeper layers and accommodate lateral demands and performance objectives. Engineering innovations from the most recent development, the roof structure over AAS, will be discussed."

Jan 1, 2016

By Morris J. D, Baldwin Z., Wiltcher P. M

21 Moorfields is an oversite development in central London spanning Moorgate tube station. It required the installation of both the highest loaded bearing piles and the highest top loaded static pile test ever undertaken in the UK, at 50.5MN (5,680 tons). The 17-storey building is founded on only 15 large diameter bored piles installed through the roof of the live station. The piles are located in two parallel rows 50 m (164 ft) apart, bridging the underlying train lines and the Crossrail tunnel below. This unique project required a diverse cross-section of skills and experience from the Project Team as we not only pushed the boundaries of design but also those of construction practices. Our team therefore needed to be made up of members from multiple businesses and disciplines. The team worked together, in a highly collaborative environment, for around two years before any work started on site. A key challenge for this project was that there was only one opportunity to construct each pile. If a position had to be abandoned there were no alternative locations and the impact on the project would have been catastrophic. It was therefore vital that all events that may have led to the abandonment of a pile were investigated ahead of commencement on site. Risk elimination and mitigation strategies were developed for all eventualities whether they be associated with the design or construction processes. The successful pile load test, coupled with all contract piles being fully instrumented with state-of-theart fiber optic (CemOptic) cable along their full length, has improved our understanding of the performance of such large and heavily loaded piles. The works piles will all be monitored during the construction of the new building, providing new insight into their real-world performance. Such groundbreaking work has never been undertaken before in the UK and has the potential to significantly influence the industry’s understanding of pile behavior, and design, in the future. This paper will discuss the challenges the team encountered during the design and construction of this highly complex urban project, particularly when adopting, by necessity, a pioneering approach.

By B. Philip Shull, Allen W. Cadden, Johanna M. Simon, Michael S. Senior

A 670 linear meter (2,200 linear foot) large-diameter sanitary sewer interceptor installation at depths ranging from 3 to 10 m (10 to 30 ft) below existing grade in an area with a high water table requires careful attention to design and performance of the system during construction. Highly variable soil and rock conditions at the site necessitated the design and construction of various excavation support systems along the alignment. In addition to the subsurface condition challenges faced at this site, the proposed sewer pipe was to be installed between an existing active combined sewer main and a high pressure gas main feeding the nearby city. What better way is there to monitor performance of the system than to require a detailed instrumentation system? Instrumentation system specifications and designs are becoming more commonplace in the industry, but it is always important to sit back and take a look at the whole picture. What are you looking to gain from your monitoring? What pieces of information are useful? What interpretations can you derive from the instrumentation you have selected? This paper will address the instrumentation system used to monitor the 670 m (2,200 ft) excavation from the specification requirements to the implementation and interpretation. This case history will delve into the challenges faced and methods used to overcome those challenges on this particular support of excavation (SOE) project. A combination of soldier pile, lagging and sheeting, and shoring systems was used to achieve the necessary excavation support. In designing the systems, attention was given to the configuration of the bracing system to allow the sections of largediameter pipe to feasibly be installed in the excavation while maintaining the SOE system.

By Joel Moskowitz, George J. Tamaro

"A new office complex is being constructed within 25m of the Hudson River in New Jersey. The project, about 140m by 100m, will include 4 basements under the entire footprint. The perimeter was to be secured by a 0.8m thick diaphragm wall, laterally supported by high capacity tieback anchors to rock. Columns were to be supported on footings or piers to rock at a nominal bearing pressure of 3.8MPa at depths up to 17m. Although some variation in rock quality was observed in borings, a substantial vertical seam of weathered and/or decomposed rock, 1 to 2 meters wide by as much as 8 meters deep, was encountered during construction necessitating field redesign. In some locations, the seam dipped below rock that is more competent. Footings were redesigned for support on drilled caissons, or soft rock was excavated and replaced with concrete necessitating a reduction in bearing pressure of the footings by one half. The tower covering the south half of the site was topped out in 2002 and the garage levels in the north half of the site were completed in 2003.PROJECT DESCRIPTIONIn September 1999, a major investment company began the due diligence process to evaluate a property on the shore of the Hudson River in Jersey City, New Jersey for a new multi-use complex. The site offers a spectacular view of lower Manhattan directly across the river from the site of the former World Trade Center. The site, covering two city blocks, was previously occupied by manufacturing and office facilities of Colgate-Palmolive.The building footprint is approximately 140m by 100m, the southern half of which is occupied by a 260m tall office tower, shown in Fig. 1. As of this writing, design of the structure for the northern half of the site has not been finalized, but it is expected to comprise an 11-story office building. A glass-covered atrium will occupy the street that formerly separated the two blocks. As part of the due diligence process and preliminary design evaluation, alternatives were considered to accommodate various numbers of parking places, both above and below existing grade. A major consideration for below grade parking is the proximity of the Hudson River some 25m east of the east building line."

Jan 1, 2004

By Dominic Parmantier, Karen Dawson, Suthan Pooranampillai, Seungcheol Shin

"This paper presents a case study of the use of single axis cement deep soil mixing (CDSM) to deal with static settlement and seismic stability of the foundation soils under a reinforced soil slope (RSS) embankment up to 50 feet high. As part of the widening of Interstate 5 (I-5) to allow High Occupancy Vehicle (HOV) lanes in Tacoma, Washington, a new approach and span over the Puyallup River will be constructed. During the soils investigation and design phase of the project, low plasticity silts (ML) inter-bedded with silty sand layers and organic silt where identified as being potentially liquefiable. CDSM was selected to address the embankment foundation concerns and allow for future trenchless installation of utility lines beneath the embankment. The presence of a confined, artesian aquifer within the design depth of the CDSM led to the installation of a depressurization system to avoid an upward gradient through the wet soil-cement. In addition to addressing the design approach, the paper discusses the challenges associated with quality assurance of CDSM within the time constraints of an ongoing project. The limited recovery rate of conventional triple tube coring in the soil-cement and double tube wet sampling led to the use of sonic coring to provide a near continuous core of the soil-cement.IntroductionCement deep soil mixing (CDSM) was used as a replacement for stone column ground improvement in a corridor which the owner, the Washington State Department of Transportation (WSDOT) wanted to reserve for future trenchless crossings beneath reinforced soil embankments within a freeway interchange. The work was part of HOV improvements to I-5 in Tacoma, Washington. The CDSM construction occurred in late 2010 and early 2011.Approximately 14,500 cubic yards of soil cement columns were placed by CDSM. The soil cement improved ground supports permanent geosynthetic reinforced slopes up to 50 feet high. The ground improvement was designed primarily to provide global stability of the reinforced slopes during seismic loading, but it was also utilized to reduce the time and total amount of settlement following construction of the embankments.This paper presents a discussion of the design approach and challenges associated with quality assurance of a relatively small volume of CDSM within the time constraints of an ongoing project. The challenges associated with attempts at collecting cores of the cured soil-cement mix cured by triple tube coring and pushing a double tube into the wet mix and allowing it to cure insitu are discussed, along with the eventual adoption of sonic coring combined with reliance on laboratory testing of wet mix samples collected daily."

Jan 1, 2017

By Matthew D. Marks

"The Sacramento Area Flood Control Agency initiated the Natomas Levee Improvement Program in 2006 which would bring the entire 42 mile Natomas Basin perimeter levee system into compliance with applicable Federal and State standards for levee protecting urban areas. The soil-bentonite slurry cutoff has been utilized as the primary construction method for addressing the under seepage deficiencies. To date, a combined total of over 4,500,000 square feet of slurry cutoff wall have been constructed utilizing excavation methods to a maximum depth of 75 feet and deep soil mixing methods to a depth of 90 feet. The construction of these cutoff walls has required the use of newly designed and custom built long boom and stick attachments for large hydraulic excavators and additional resource will be required to complete future phases. Key components of the NLIP program have included advancements in the development of soil-bentonite backfill mix designs, specified ranges on the soil backfill gradation to address concerns of long term consolidation of the backfill material, evaluation of the trench slurry filtrate loss with regard to cutoff wall acceptance, maintenance high slurry densities to provide greater trench stability, and continued development of backfill mixing procedures.IntroductionThe Natomas Levee Improvement Program (NLIP) was initiated by the Sacramento Flood Control Agency (SAFCA) in 2006. The long term objective of the NLIP is to provide 200-year level flood protection to the basin. To date, approximately 21 of the 42 mile Natomas Basin perimeter levee system has been completed, totaling over $100,000,000 in construction contracts, of which slurry cutoff walls make up approximately $25,000,000. Other construction elements include excavation and removal of unsuitable levee materials, raising or widening existing levees, construction of landside seepage berms, drainage canals, and miscellaneous structures.Although each construction phase of the NLIP includes various construction elements of levee restoration program, the slurry cutoff wall is the primary construction element for addressing the under seepage deficiencies. To date, approximately 4,500,000 square feet of slurry cutoff walls have been installed using excavation and deep soil mixing (DSM) methods. This includes approximately 2,000,000 square feet of slurry cutoff wall along 5 miles of the NCC South Levee and 2,500,000 square feet of slurry cutoff wall along 16 miles of the Sacramento River East Levee (SREL). The work has been completed under 8 separate contracts, through SAFCA, and performed between September 2007 and December 2012. A summary of the contract phases and associated cutoff wall square footage is provided in Table 1. Most of the work has been performed within the seasonal dry weather period in the Sacramento valley, which occurs between April and October. This has required much of the work to be performed on an aggressive construction schedule, year after year."

Jan 1, 2017

By Greg Nutson, Jeremy Butkovich, Bill Perkins, Hollie Ellis, Paul Bott

"Dynamic soil-structure interaction (DSSI) analyses are becoming more common in bridge designs, especially in seismically active areas. Because of its proximity to two active fault zones, the Evergreen Point west approach bridge replacement will be base isolated, and will be designed using DSSI. The project team completed two independent bridge designs to satisfy peer review requirements. The designs required substantial characterization of the soil dynamic behavior using both laboratory and in-situ testing. The analyses made use of earthquake time histories spectrally matched to conditional mean spectra. This led to reduced, and more realistic seismic demands on the structure, compared to conventional uniform hazard spectrum matching. The bridge analyses suggest that the preliminary bridge design is relatively conservative. This will allow the design team to potentially reduce shaft/column diameters and reinforcement. The design team estimates that the dynamic analysis design could represent a net savings of around $60 to $90 million compared to a conventional design.INTRODUCTIONThe Evergreen Point Bridge conveys State Route (SR) 520 2.6 miles (4.2 kilometers [km]) from Seattle to Medina across Lake Washington. The bridge is located in a seismically active area, and the Washington State Department of Transportation (WSDOT) has determined that the western half of the 1960s-era bridge (the “west approach”) is vulnerable to earthquake damage. WSDOT has begun preliminary design to replace the west approach bridge.The west approach extends about 6,100 feet (1,900 meters [m]) east from Seattle’s Montlake neighborhood, over Union Bay and Foster Island, then into Lake Washington proper (Figure 1). Approximately 5,600 feet (1,700 m) of the replacement bridge would be constructed over water. Subsurface conditions along the bridge alignment consist of 5 to 80 feet (2 to 24 m) of very soft peat and clay, over very dense/hard sand and clay. Multiple pile supported columns support the existing bridge. The new bridge would be supported by 8- to 10- foot-diameter (2.4 to 3.0 m) drilled shafts that extend about 50 feet (15 m) into the underlying very dense/hard soil. To reduce seismic demands on the bridge superstructure, WSDOT has decided to incorporate a base-isolation system into the bridge design."

Jan 1, 2017

By Andrew J. Ciancia

The construction of the Pennsylvania Station in Manhattan, the Beaux-Arts masterpiece, was completed in 1910. In financial ruin, the Pennsylvania Railroad Company sold the station in the 1960?s and the new Madison Square Garden and the Penn Plaza complex were constructed at the site. The demolition of Pennsylvania Station brought public awareness and outcry to protect historic structures and the Landmarks Preservation Commission (LPC) was subsequently established in 1965. In the 1960?s relatively little engineering data was available on the performance of historic structures during adjacent construction and thus, no published criteria were established by the LPC on allowable movements and vibrations. During the late 1970?s a commercial tower was planned adjacent to the landmark Fraunces Tavern Block (FTB) in lower Manhattan. Through negotiations between the LPC and the developer, Dr. M. I. Esrig and the author were retained to monitor the historic block during foundation construction. The monitoring data and building performance compiled from the project formed the basis of the published 1981 ASCE technical paper by Esrig and Ciancia entitled ?The Avoidance of Damage to Historic Structures Resulting from Adjacent Construction?. Based on the ASCE paper, the NYC Department of Buildings adopted Technical Policy and Procedure Notice #10/88 entitled ?Procedures for the Avoidance of Damage to Historic Structures Resulting from Adjacent Construction When Subject to Controlled Inspection by Section 27-724 and for Any Existing Structure Designated by the Commissioner?, June 1988. This paper describes the author?s recent experience during the installation of deep foundations within, or adjacent to, three Manhattan landmark structures. Discussions are provided on the foundation construction, monitoring programs and performances of the three structures.

Jan 1, 2008

By John Wise

Significant movement to an existing slurry wall which serves as a retaining wall on 'O' Street in Southeast Washington, D.C. initiated the Department of Public Works for the District of Columbia to invite specialty contractors to propose a rehabilitation and stabilization for the failed slurry wall. Nicholson Construction Company proposed and was awarded a contract for the construction of an anchored precast lagging and soldier pile wall to be located approximately 4 feet in front of the existing structure with granular fill placed between the new and existing walls. Stabilization of the existing slurry wall also included drilling horizontal weep holes and demolishing the failed panels down to the existing ground surface. A new and improved drainage system was also constructed to increase the amount of water directed toward the existing storm sewer system running along 'O' Street. This paper provides a detailed account of these construction activities.

Jan 1, 2003

By F. Keith Jacobson

To be involved in the construction of a deep dredged caisson for a major bridge pier is one of the most rewarding and professionally challenging experiences one can have in the bridge construction business. That experience was doubled in the construction of the two deep dredged caissons for the Highway 82 Bridge over the Mississippi River near Greenville, Mississippi. The challenges and the construction risks associated with constructing these two dredged caisson pier foundations highlight the construction engineering innovation associated with major bridge pier construction. The 1,378-foot Main Span of the Highway 82 Bridge makes it the longest cable stayed bridge span over the inland rivers of the United States. The main piers for this bridge are supported on two dredged caissons measuring 80-feet by 122-feet in plan, founding 200-feet and 170-feet below the river surface. The challenges of constructing these caisson structures, sinking them through 70-feet of water to the river bottom and then excavating and further sinking them to the founding grade without exceeding the design tolerances, were enormous. The construction engineering opportunities for innovation included major breakwater structures to create a friendly environment in 11 fUsec currents, the first time use of Articulated Concrete Mattresses for river bottom scour control, unique air dome design to maximize the buoyancy of the caisson structure while floating, a caisson guide system to assure positive control and positioning of the caisson during the initial sinking phases. and a comprehensive sinking plan to assure maximum control and minimum risk. Many of the innovative solutions to the construction challenges on this bridge will be incorporated into future caisson construction projects on the lower Mississippi River.

May 11, 2007

By Claudio Asioli

"The project’s goal was to construct the Al Ghazala Intercontinental, a multi-use development in the bay area of Tripoli overlooking the Mediterranean Sea. The site of the project is located approximately 500 ft (150 m) from the Mediterranean coast, near the Al Ghazala roundabout in the town center of Tripoli, Libya. The investor of the project was Magna Properties Group, Ltd. – Libya, the main contractor was Man Enterprise S.A.L., and the design and construction management was performed by Dar Al-Handasah Engineering. Trevi S.p.A. was contracted to perform the design and construction of the anchored diaphragm walls and dewatering systems for the excavation of a two-level basement car park, which extends across the full footprint of the site.The site was approximately 640 ft by 230 ft (195 m by 70 m) in plan and nearly flat. The groundwater level typically varies from about 11 ft to 23 ft (3.4 m to 7.0 m) above mean sea level. To construct the required raft foundation, it was necessary to excavate the area down to El. -15.7 ft to -26.3 ft (-4.8 m to -8.0 m), which resulted in an excavation depth ranging from about 27 ft to 39 ft (8.3 m to 12.0 m) below the existing ground surface. Subsurface ConditionsThe subsurface site investigation was performed in three phases by Al-Tamier Engineering Consulting Bureau. During Phase 1, a preliminary investigation was undertaken during the early stages of the project to obtain information about the general stratigraphy and groundwater level at the site. Phase 2 was performed to obtain subsurface information and design parameters, and Phase 3 was performed as a supplementary ground investigation to investigate unexpected ground conditions identified during Phase 2. In total, 14 boreholes were drilled to depths ranging from about 80 ft to 180 ft (24 to 55 m). The generalized subsurface profile is quite heterogeneous, and is predominantly composed of sand with silt and gravel that is underlain by limestone, calcarenite and claystone."

Jan 1, 2017

By Christian L. Escalera

Over seven years ago, on October 29, 2012, Superstorm Sandy pummeled the Northeast of the United States inflicting heavy damage on New York City Transit’s (NYCT) system. Since then, NYCT has been methodically rehabilitating and hardening its assets to upgrade service and prevent future impacts caused by similar devasting storm surges. Part of these resiliency efforts, NYCT’s 207th St Yard Project is one of many projects that make up the Sandy Repair and Flood Mitigation Program. The work to be performed on the 207th Street Project includes building a perimeter Floodwall along the Harlem River, extending up 215th Street and 9th Avenue with the intent of having the ability to withstand a 500 Year Storm flooding event. The original 1,535 lineal feet of the marine side floodwall design consisted of 937 each W40x235 H-Piles continuously welded to PS 27.5 flat sheet to form an interlocked and composite steel seawall that would protect the NYCT 207th Yard from a storm surge of the Harlem River. However, after the Contract was awarded and a Notice to Proceed was issued, Walsh Construction Company II (WCCII) partnered with Mueser Rutledge Consulting Engineers (MRCE) to propose a redesign of the marine wall section as a Value Engineering Change Proposal (VECP). This VEP redesign is comprised of 279 each 54in Diameter Steel Pipe Piles that are interconnected with continuously welded PZ 35 sheet piles interlocks. The intent of the VEP was to provide a cost savings that could be shared by both parties as well as alleviate some constructability and alignment control concerns that WCCII had expressed to NYCT. The VEP allowed WCCII to substantially lower the total cost which was shared between NYCT and WCCII.

By Adrian Mercer, Ashkan Ameri

Due to general degradation, increased traffic levels, and historical ground movement, this road and rail bridge which provides an essential link between the interior of the country and the Port of Abidjan, required significant repair and reinforcement. This included strengthening the pre-stressed concrete box girders and replacement of the existing bored pile foundations. Replacement piles had to be adjacent to, and no longer than, the existing piles, in order to not compromise the stability of the operational bridge during the works. The underlying geology, however, meant that the pile loads had to be predominantly transferred into the ground through end bearing. Rather than installing a greater number of piles or larger diameter piles, innovative thinking changed the usual mind-set of designing the piles to the prevailing ground conditions, to designing the ground conditions to suit the piles. Jet grouted columns were installed beneath the toes of the new piles to increase the bearing capacity of the ground. This significantly contributed to the sustainability of the project and reduced carbon emissions through saving concrete, steel, plus transportation and disposal of spoil.

Sep 8, 2021

By Christophe H. Locussol

D.C. United, the professional soccer team located in Washington, D.C., completed a 20,000 seat capacity stadium in July 2018 named Audi Field. The project initially considered a foundation system consisting of roughly 800 prestressed concrete driven piles configured in groups with pile caps. A value engineering alternative proposed in a design-build manner ultimately resulted in the use of 300 single element Auger Cast Piles (ACPs) for the foundation system. The ACPs ranged between 1.5 ft and 4 ft in diameter, were up to 85 ft in length, and were connected through a system of grade beams to accommodate large lateral induced loads. Limitations in conventional analytical methods were encountered during the structural design of the piles due to the complexity of the lateral loading and pile fixity conditions. An innovative approach using advanced finite element modeling that incorporated the framing effects of the grade beams was required to meet the strict movement criteria despite large lateral loads.

By Brian J. Olson, Kevin Haiar

Originally constructed between 1939 and 1941 as part of Franklin D. Roosevelt’s New Deal programs, the Bonneville to Hood River 115 kV Transmission Line required an infrastructure upgrade to remain reliable and in-service. The line traverses the rugged landscape of the Columbia River Gorge on the Oregon- Washington border, featuring steep, talus slopes; uneven, rocky terrain; and a variety of environmental sensitivities. This paper details the design and construction of 27 micropile foundations for new, fire- hardening steel poles through a particularly challenging stretch of the alignment. The difficult access and environmental constraints at these sites designated them as helicopter-accessible and precluded the collection of detailed geotechnical information prior to construction. Micropiles provided a viable foundation alternative due to their portability and flexibility during construction. Detail will be provided on the extensive preliminary desktop study performed, as well as the process of developing engineering designs to successfully accommodate for variability and unknowns in complex geological conditions. With an increasing number of electric power projects traversing challenging terrain and facing similar obstacles, this project stands to provide valuable lessons learned to the industry.

Sep 8, 2021

By Md. Nafiul Haque, Murad Y. Abu-Farsakh, Chris Nickel

"This paper presents the results from a pile load testing program for a bridge construction project in Louisiana. The testing includes two 54-inch open-ended spun cast concrete cylinder piles (OECP), one 30-inch open-ended steel pile (OESP), and two (30-inch and 16-inch) square prestressed concrete (PSC) piles driven at two locations with very similar soil conditions. All the test piles were instrumented with vibrating wire strain gauges to measure the load distribution along the length of the test piles and the skin friction and the end bearing were derived from strain gauge measurements. High strain dynamic load tests (HSDLT) were performed on all test piles at different times after pile installations to quantify the amount of setup with time. Static load tests were also performed on the PSC and open-ended steel piles. Due to expected large pile capacities, the statnamic test method was used on the two open-ended cylinder piles. The pile capacities of these piles were evaluated using various CPT methods (such as Schmertmann, De Ruiter and Beringen, LCPC, COFS methods). The result showed that all the methods can estimate the skin friction with good accuracy; but not the end-bearing capacity. Setup was observed for all the piles, which was mainly attributed to increase in skin frictions. The setup rate parameters “A” [The “A” parameter is defined as the rate of increase of pile capacity ratio (Rt/Rto) per log cycle of elapsed time] were back-calculated for all the test piles and the values were between 0.31 and 0.41.INTRODUCTIONDue to greater efficiency (capacity to weight ratio) of the pipe piles, open-ended piles are a viable option to solid piles. However, the behavior of open-ended piles is more complicated compared to the close-ended piles owing to possible formation of “soil plug” inside the open-ended pile. Many researchers have analyzed the behavior of both types of piles for different purposes; however, very few studies in the literature offer the side-by-side comparison of the close-ended and open-ended piles."

Jan 1, 2017