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By Diego Bellato

Production data recorded by special foundation rigs during construction activities at the site are commonly used for quality assurance / quality control procedures and, in particular, to prove that the installed foundation elements comply with the geometrical and quality requirements defined in the design specifications. Parameters such as crowd force, penetration/withdrawal rate, rotational speed etc. are usually presented in reports in the form of depth and/or time profiles. This type of protocols are already standard QA/QC solutions for ground improvement methods like deep soil mixing or jet-grouting, but they are quite rarely applied in combination with other techniques like diaphragm walls or Kelly drilling. In the latter cases, one of the main reasons behind this lack of site documentation is related to the difficulty in interpreting huge amount of data collected during the creation of single elements, which, in some cases, can last several days (not always in a row). In addition, the building sequence is often characterized by many alternated operations involving different movements of the rig and the use of different tools. In this context, the identification of specific construction activities based only on the mere exam of the time profiles of the recorded production parameters is extremely difficult. In this paper, the time profiles of production parameters obtained from a fully-cased Kelly drilling rig employed on a site in Karlsruhe (Germany) have been investigated and compared with a detailed series of activities deduced from a video filmed during installation. Typical time profile patterns associated to specific procedures have been identified by combining the different information available. The outcome of this study helped project engineers to automatize the recognition of activities directly from production data and led to an overall understanding and optimization of the construction process. INTRODUCTION The special foundation industry is characterized by the use of highly sophisticated machinery for the realization of geotechnical systems such as piled rafts, retaining walls and slabs for excavation pits, cut-off walls for levees and embankments or ground improvement solutions. Rigs can vary in size, weight, and power and can be provided with several drilling tools to cope with the different soil conditions (e.g. clay, sand, rock) and the different geometries of the elements to be built at the site (e.g. micro-piles, large- diameter bored piles, diaphragm walls, anchors). Due to the challenging construction procedures, various types of sensors have started to be mounted on the equipment in the last decades to monitor the behavior of some important machine parameters and to inform rig operators about the on-going process and the status of their devices.

Jan 1, 2019

By Helen D. Robinson

Traditional practice to resist large lateral loads on foundations is the use of large diameter caissons, battered driven piles, or battered micropiles. Dense urban construction environments, however, limit the usefulness of these systems due to the close proximity of below- and above-grade obstructions. This paper presents two micropile construction projects in the United States where a complex scheme of battered micropiles and grade beams was developed to counteract large lateral loads at the foundation level. The paper also presents a procedure used to design vertical micropiles for large lateral loads, which can greatly simplify the design of foundations subject to significant lateral loads in urban environments. A design example shows a case where vertical micropiles were used to support allowable design lateral loads greater than 80 kip per micropile.

Jan 1, 2010

By Marco Fellin, Van E. Komurka

Significant cost and construction benefits were obtained from performing a bi-directional static load test prior to construction on the Russell Street Bridge Replacement project in Missoula, Montana. The project utilized 24 drilled shafts to support two three-span bridges across the Clark Fork River. A bi-directional static load test (“BDSLT”) was performed on a large-diameter production shaft to demonstrate construction methods and confirm design assumptions. Subsurface conditions consisted of gravel with sand to a depth of 20 feet (6.1 m), underlain by gravel with sand, silt, cobbles, and occasional boulders. The test shaft had a nominal diameter of 5.9 feet (1.8 m), and an embedded length of 75.5 feet (23.0 m). The geotechnical engineer of record and the BDSLT test engineer collaborated to optimize the BDSLT jack assembly location within the test shaft, determine appropriate instrumentation locations, and plan the test protocol. The maximum applied test load was 10,707 kips (47.6 kN). Significant benefits were obtained from performing the BDSLT test, including 1) reducing each production shaft’s length by using a higher LRFD resistance factor allowed by having performed the testing, 2) using test-determined unit shaft resistances to evaluate and accept two production shafts that may have otherwise required remediation, and 3) providing the Montana Department of Transportation (and other designers) with increased presumptive unit resistance values in the gravel/cobble/boulder deposits. PROJECT DESCRIPTION The project was constructed in Missoula, Montana for the Montana Department of Transportation (“MDT”). The original bridge was approximately 60 years old, and consisted of a two-lane, 420-foot-long (128-m), four-span, riveted steel plate girder design spanning the Clark Fork River. The bridge was due for replacement owing to its deteriorated state, and the need for increased traffic volume capability afforded by a four-lane structure. HDR was the structural engineer. The preferred bridge alternate was a 459-foot- long (140-m), three-span, welded steel plate girder design. The new bridge was designed to meet current standards in accordance with MDT bridge design and AASHTO LRFD criteria. The new bridge was constructed in phases to keep traffic open during construction.

Jan 1, 2019

By Charbel Khoury, Kwabena Ofori-Awuah, Kofi B. Acheampong

"Following heavy rains in spring of 2014, Prince George’s County officials issued a mandatory evacuation for homes in the Piscataway Hills subdivision of Fort Washington, Maryland where a landslide along a 1700-foot hillside destabilized homes, collapsed the single access road, and resulted in water and sewer mains break. Forensic investigations, including geologic assessments, test borings and in-situ Cone Penetrometer and Dilatometer soundings, were performed to evaluate subsurface conditions and provide stabilization options for the roadway and slopes. Post-failure ground movements were monitored using inclinometers. Critical failure planes were identified within the underlying 30-foot thick Marlboro Clay formation, a known geologic hazard with historic occurrences of landslides and slope failures.This paper discusses the remedial design for stabilizing the landslide and 60-foot hillside slope failure, and protecting the roadway. Amongst several feasible options, driven piles were selected in consultation with the County and retained contractor based on cost, environmental impacts and site constraints. Constraints included private ownership of hillside slope, upslope buildings safety; deep-seated failure, relocation of underground water and sewer mains, and accelerated construction schedule.Pile design included global slope stability analyses and lateral pile analyses using several loading configurations to optimize pile geometry and spacing, and determine a value-engineered design satisfying both serviceability and strength limit states to achieve long-term stability with factor of safety of 1.3. Soils within the active landslide plane were assumed to provide no resistance, while soils below the failure plane provided lateral resistance. This stabilization scheme, which extended along the 1700-foot roadway section and toe of hillside slope area, consisted of 410 steel HP16x141 piles in two to three rows driven to depths between 60 and 70 feet below the Marlboro Clay stratum at 5 to 7-foot spacing."

Jan 1, 2017

By Alice DiDonna

The heating and cooling of buildings worldwide represent a large amount of a country?s energy needs and are major sources of CO2. Therefore, decreasing the environmental impact of residential and office buildings is of crucial importance. Energy pile foundations are a sustainable solution to this problem and constitute a local, renewable and environmentally friendly resource. They are also in accordance with current energy policies. A system of pipes installed within the concrete with a heat carrier fluid that circulates through it can extract heat from the ground to satisfy the need for heat during the winter and expel excess heat resulting from air conditioning during the summer. Consequently, the foundation is subjected to a thermal load, which results in additional stresses and strains that must be considered in the design process. Despite the fast spread of this technology in the last decade, there is still a lack of knowledge about the thermo-mechanical behavior of energy pile foundations. Consequently, design approaches and guidelines are limited. Here, a new geotechnical method for the design of energy piles is illustrated based on the quantification of the additional thermal effects that appear inside the foundations. The method is based on the load-transfer curves approach and has been implemented into a numerical tool called ThermoPile. The software is presented and validated through a developed analytical solution and the results are compared with real in situ experimental tests.

Jan 1, 2011

By David P. Sauls

Design-build contract delivery provides unique opportunities for efficiencies in pile foundation design and installation. The Louisiana Department of Transportation and Development (LADOTD) US Highway 90 at Louisiana State Highway 85 (US90/LA85) intersection was contracted under the design-build delivery system, in part to take advantage of these efficiencies. As one of five projects recognized by the Design Build Institute of America (DBIA) when it honored LADOTD as its 2011 Transportation Owner of the Year in the highway/bridges category, the design-build method provided a way for this project to be ?shovel-ready?, which enabled the LADOTD to secure American Recovery and Reinvestment Act (ARRA) funding. This paper describes the benefits this project gleaned from the design-build process, which included synergy, schedule, design and construction efficiencies, and team building. Interlaced with design and construction of precast prestressed concrete (PPC) piling in compressible southern Louisiana soils, the design-build process rapidly translated computations to cost and schedule savings. A robust quality assurance program using Pile Driving Analyzer (PDA) equipment to evaluate pile set-up provided expedited acceptance of bridge bents and advanced construction schedule. Data evaluation includes analyses of PDA data obtained from 1-hour, 24-hour, 7-day, 14-day and 6-month restrikes of the project test pile.

By Stefano Pirrello

"Sydney’s booming real estate market has pushed property developers to invest in historically “no-go” areas, which were previously too expensive to develop. These areas are usually near rivers where the sites are underlain by deep alluvial and estuarine sediments. In these ground conditions conventional bored pile techniques are often not competitive. Contiguous Flight Auger (CFA) and Drilled Displacement Piles (DD) techniques are on the other hand suitable for these ground conditions. This paper deals with the design and construction challenges encountered with these piling techniques for a series of high-rise towers in Sydney’s West. The advantages of DD over CFA piles such as reduced overall spoil with substantial cost savings and achievable rock sockets in medium strength bedrock are discussed. Design validation through interpretation of real-time data from the piling rigs’ on-board computer data, and low and high strain pile dynamic testing (PDA) is discussed. Testing data is presented as CAPWAP (Case Pile Wave Analysis Program) analyses for different concrete grades.INTRODUCTIONThe booming real estate market in Sydney has pushed property developers in investing in historically “no-go” areas, which were previously too expensive to develop. These areas are usually near rivers where the sites are underlain by deep alluvial and estuarine sediments. In these ground conditions conventional bored pile techniques are often not competitive. Contiguous Flight Auger (CFA) and Drilled Displacement (DD) Pile techniques are on the other hand suitable for these ground conditions and were utilised using concrete injection methods. This paper deals with the design and construction challenges encountered with these piling techniques for a series of high-rise towers in Sydney’s West.GEOLOGY & GEOTECHNICAL CHARACTERIZATION OF THE SITEThe Sydney 1:100 000 Geological Series Sheet shows that the site is underlain by man-placed filling and alluvial/estuarine sediment. The sediment comprises silty to peaty sand, silt and clay. Shell layers are also expected to be present within the soil profile. The Prospect/Parramatta River 1:2500 Acid Sulphate Soil Risk Map shows the site as ‘Disturbed Terrain’ in which soil investigations are required to assess acid sulphate soil potential. Several Cone Penetration Tests and Boreholes were carried out during the geotechnical investigation. All boreholes were extended to bedrock and NMLC-sized diamond core drilling was used to obtain 50mm continuous core of the rock, enabling unconfined compression strength testing to be carried out on selected samples. A summary of the ground conditions encountered on this site and inferred from the CPTs can be described as follows:"

Jan 1, 1900

By Yan Lap J. Kan

"A waterfront stabilization system consisting of Deep Soil Mixing (DSM) columns, vinyl sheet pile fascia, and concrete flood walls supported on shallow footings was designed and constructed for a high-density waterfront development in Northern California. The project site is underlain by soft, compressible organic soil locally known as Bay Mud that has been capped with loose sand and imported fill. The waterfront stabilization system constructed at the site mitigates liquefaction, consolidation settlement and seismic potential slope deformation along the waterfront; the system was designed to reduce lateral displacements to tolerable amounts for the proposed structures. This paper presents the general design methodologies, construction challenges and quality control of this waterfront stabilization system.INTRODUCTIONUrban development in Northern California is fueling innovations in geotechnical engineering as more complex sites are developed. ENGEO Incorporated introduced a deep soil mixing technology from Japan to the US and designed a waterfront stabilization system for a high density waterfront development project in Redwood City, California. The approximately 12½-acre project site, as shown on Fig. 1, is surrounded by water on three sides, with an inner marina at the center of the site.The project site is located in the seismically active San Francisco Bay Area in California. The San Andreas Fault, the Monte Vista-Shannon Fault, the Hayward Fault and the San Gregorio Fault are major active faults located within 25 miles of the site. Once a former marshland with a major slough until the late 1950s, the site was reclaimed by placing imported fill over the native compressible clay deposits, locally known as Bay Mud."

Jan 1, 2016

By Cheng Lin, Guoming Lin

"This paper presents a case history for the design, construction and long-term performance monitoring of a driven prestressed concrete (PSC) piled foundation supporting a large liquefied natural gas (LNG) tank in Savannah, Georgia, USA. Following a geotechnical investigation, a design stage pile test program was performed with three objectives: to study the densification effect from pile driving on the liquefaction resistance, to test axial and lateral pile capacities, and pile behavior under lateral loads. The test program comprised five piles driven on a test pad constructed adjacent to the tank foundation. Cone penetration testing (CPT) was performed before and after pile installation to test soil densification effects from the pile driving and liquefaction potential was re-evaluated based on the soil densities after pile installation. The axial load tests involved static load testing, high strain dynamic testing, and Statnamic testing. This paper presents the findings of the densification effects, compares results from different axial testing methods and discusses the procedures to use the load test results in the pile design. The paper also comments on the construction issues and presents performance data with 10 years of monitoring.1. IntroductionThe project site is located at the Kinder Morgan’s Elba Island LNG Terminal on the Savannah River which is three miles downstream of the downtown Savannah, Georgia. This LNG terminal was initially developed in the 1970s as an LNG import terminal. The facility includes five LNG storage tanks with two larger tanks which were constructed in 2003 and 2006, respectively. The terminal is currently being converted into a liquefaction and export facility. This paper discusses pile foundations for Tank D4 which is a double walled insulated steel tank built to hold one million barrels of LNG in 2003. This tank has an outer tank diameter of 258 feet, an inner diameter of 252 feet, and liquid height of 113 feet. A number of geotechnical challenges were present in the foundation design and construction.??The site is a typical coastal deposit site featuring a thick layer of very soft under-consolidated clay (up to 40 feet in thickness);??The bedrock is a couple of thousand feet deep;??There is a sand layer that is liquefiable under a high seismic design category (0.5% possibility of exceedance in 50 years)."

Jan 1, 1900

By Joel B. Dellaria, Justin R. Lewis

"No. 9 Walton is a new high-rise condominium building located in the Gold Coast area of Chicago. The adjacent building, Walton on the Park, featured 4 levels of below grade parking and utilized a secant pile wall with integral drilled shafts to support the exterior columns. The earth retention system (ERS) for No. 9 Walton also employed a secant pile wall in combination with drilled shafts. The excavation into the soft Chicago clays varied in depth from 9.75 m to 12.5 m (32 feet to 41 feet) below grade. The temporary excavation support used internal braces from the new secant piles to the existing foundation system of Walton on the Park to provide earth retention. Engineering teams for both projects worked together to design the bracing scheme and connections to ensure that the new excavation and internal bracing would not overstress any elements of the existing structure. Further complicating the project, immediately to the west of the project was a historic church founded on shallow spread footings which required underpinning to minimize movements.The project involved three different building owners, small values for acceptable wall movement, an extensive monitoring program and the challenges of merging two earth retention systems. The subsurface conditions at the site, the adjacent structures, the excavation, and the performance are described. A summary of the design methods and the expected movements of the ERS are discussed, and the performance monitoring system is described. Overall, the ERS performed better than expected with less than 1 inch of measured lateral wall movement during and after the excavation was completed. Measured performance of the ERS is compared to the predicted performance and to the performance requirements for the project.INTRODUCTIONNo. 9 Walton is a new high-rise condominium building in Chicago located in the Gold Coast. The building has 3 levels of below grade parking and 36 levels of living space above grade. Developers originally slated the project to be Phase 2 of the Walton on the Park development built in the mid 2000’s, using portions of the existing foundation system for development of the new structure. However, the housing market crash in 2007 prompted cancellation of Phase 2 of the Walton on the Park development. The property sat undeveloped until 2015 when design and construction for No. 9 Walton began under a new development and design team. The project team completed foundation excavation and below grade structures in 2016 with the first units of the building turned over to new homeowners in 2017.The structural design for No. 9 Walton consisted of reinforced concrete columns and slabs, supported laterally by a heavily reinforced concrete central core. Drilled shafts to rock supported the interior columns and core with the exterior columns and foundations integrally included in the earth retention system. The structure had a below-grade footprint of approximately 1,490 m2 (16,000 ft2). The general excavation extended 9.75 m to 12.5 m (32 feet to 41 feet) below street level with the deepest portions at the central building core mat foundation."

Jan 1, 2017

By Marco D. Boscardin, Kenneth A. Pidgeon, Adriane G. Boscardin

"Hollow bar tiebacks can offer an economical alternative to conventional solid bar and strand tieback systems for use in temporary excavation support construction. However, the limitations associated with the installation of hollow bar tiebacks require special attention during design, construction and load testing to verify conformance with conventional performance and proof testing criteria (PTI, 2014). In particular, providing a reliable free length is complicated by the 10-foot (3-m) -long, segmental, couplingto- coupling nature of the free length sheath in the hollow bar system, and addressing the fully grouted annulus of the bond zone and the free length zone at the end of installation are key concerns. In addition, it is often more convenient to install a greater number of more closely spaced, lower capacity tiebacks with the hollow bar system, compared to conventional tiebacks. This paper examines how these issues were addressed for a project involving a 60-foot (18-m) -deep sheet pile excavation through a highway embankment and a 70-foot-deep sheet pile and soldier pile and lagging excavation through a railroad embankment, both supported by a hybrid system of hollow bar tiebacks and hollow bar soil nails. The project involved approximately 300 tiebacks and 400 soil nails.INTRODUCTIONEngineers Construction, Inc. (ECI), constructed a pair of 32-foot (9.8-m) -wide (clear span), 30-foot (9- m) -high (21 feet (6.4 m) above the stream bed), cast-in-place concrete arch culverts as a design-build project for the Vermont Agency of Transportation (VTrans) in East Ryegate, Vermont. The new culverts replaced an existing 8-foot (2.4-m) -wide by 6-foot (1.8-m) -high cast-in-place concrete culvert under US Route 5 (RTE5), and twin, 2-foot (0.6-m) -wide by 5-foot (1.5-m) -high granite block culverts under the Washington County Railroad (WACR) alignment. The culverts convey Manchester Brook eastward, through the embankments for RTE5 and the WACR, on its way to the Connecticut River. The Connecticut River is located approximately 100 feet (30 m) east of the WACR embankment. The existing structures were undersized and backed up water behind the embankments during high flow events; and often trapped debris that flowed down the brook and became clogged. The existing culverts also had cracks and openings that have resulted in the loss of ground into the culverts and the formation of sinkholes in the sides of the embankments. Moreover, the reason for the large cross-sectional dimensions of the culverts was to make them of sufficient size and openness to encourage the migration of fish up the stream to spawn. The culvert through the RTE5 embankment is 144 feet (44 m) long, and the culvert through the WACR embankment is 128 feet (39 m) long, with a 57-foot (17.4-m) -long by 32–foot (9.8- m) -wide by 17-foot (5.2-m) -deep 10 feet (3 m) deep above the stream bed) open channel section between the two culverts. A plan view of the culvert alignment is presented in Figure 1."

Jan 1, 2016

By Anthony T. C. Goh

"For deep excavations in soft clay, it is common to use jet grouting piles (JGP) prior to excavation to minimize wall deflections and ground settlement, and to prevent basal heave instability. In this paper, finite element analyses were carried out to assess the basal heave factor of safety for excavations in soft clay supported by JGP. Comparison of the factor of safety from the finite element analyses with limit equilibrium methods was then performed. Subsequently, to account for the uncertainties in the soil and JGP properties, a simplified reliability analysis procedure is proposed to estimate the probability of basal heave failure for deep excavations supported by JGP.INTRODUCTIONJet grout piles (JGP) are often used to prevent basal heave instability and to minimize excessive wall and ground movements associated with deep excavations in soft clay deposits (Shirlaw 2003; Wen 2005; Ou 2006). The jet grouting process which is carried out prior to any excavation works produces a series of short overlapping grout columns resulting in a “continuous” base slab (commonly termed as jet grout pile or JGP) below the final excavation level that spans across the entire excavation (Gaba 1990; Hsieh et al. 2003; Ho and Hu 2006). Typically, the JGP thickness ranges from 2 m to 4 m.The focus of this paper is on the assessment of basal heave instability for deep excavations in clay stabilized with JGP. Finite element analyses were first conducted to determine the basal heave factor of safety for deep excavations in clay with JGP. Comparisons were then carried out with factors of safety based on conventional limit equilibrium methods. Since the conventional factor of safety approach does not explicitly reflect the uncertainties of the soil and JGP properties, it is demonstrated in this paper that a simple reliability based approach (Hasofer and Lind 1974) can be used to assess the probability of basal heave failure.LIMIT EQUILIBRIUM METHODFor excavations is clay, the Terzaghi (1943), Bjerrum and Eide (1956) and Eide et al. (1972) methods which are based on bearing capacity theory, are commonly used to determine the basal heave factor of safety. Another commonly adopted method in Japan and Taiwan is the slip circle method which involves taking moments about the lowest strut level (JSA 1988; Hsieh et al. 2008; Luo et al. 2012). The slip circle method has also been applied for excavations with a JGP at the base by incorporating the undrained shear strength of the JGP. In the slip circle method, the basal heave factor of safety FSslip is assessed by taking moments about the lowest strut level (Fig. 1)"

Jan 1, 1900

By Sumit Kumar Biswas, Moyukh De, Sibapriya Mukherjee

"The piles often are also subjected to lateral (horizontal) forces and moments. In fact, there are some structures where the primary function of piles is to transfer lateral loads to the ground. Proper analysis of laterally loaded piles is very important to the geotechnical and civil engineering profession.In the present investigation an experimental study has been carried out with free head short model cast iron hollow piles of outer diameter of 24 mm and L/d ratios of 8, 10, and 15. The experimental results have been supplemented by numerical techniques using PLAXIS-3D Foundation version 2.1 software. The results have been found to agree reasonably well with the experimental results. Further finite difference approach has been adoptedto reduce the computational time and to calculate the coefficient of modulus of subgrade reaction (?h) from the load- deflection data obtained from PLAXIS output at different pile depths. The parametric study has been extended for the non-dimensional form defined as flexibility ratio (F.R.),where ?h, L, Ep and Ip are the coefficient of modulus of sub-grade reaction, the embeddedlength of model pile, elastic modulus of pile material and the moment of inertia of model pile about the central axis respectively).The variation of coefficient of horizontal modulus of sub-grade reaction (?h) has been studied with respect to the following parameters for homogeneous soil system: relative density andL/d ratio. It has been found that the logarithm of flexibility ratio increases with increase inrelative density and increase inL/d Ratio. The values of ?h obtained by the proposed method have been, found to be close to the numerical results.As output of this research, graphs have been generated in respect of different parametric variations to gain an insight into behavior of piles under lateral load for short piles."

Jan 1, 2015

By Aniruddha Sengupta, Rana Chattaraj, G. R. Reddy, Raj Banerjee

"Earthquake induced liquefaction in saturated granular soils is an important phenomenon which causes severe damage to life and property. In the present study, dynamically induced liquefaction of saturated Kasai River sand is studied in 1-g shake table to assess its liquefaction potential. In the shake table, the soil was subjected to sinusoidal motions of amplitude 0.35g at a frequency of 2Hz. A numerical model using FLAC 2D (Itasca 2005) was performed to simulate the shaking table tests. Reasonably good agreement between the experimental and the numerical results has been observed. Moreover, wavelet analysis has been conducted to identify the occurrence of liquefaction in sand and to correlate the observations found from the experiments. The nonlinear curves used to represent shear strain dependency of stiffness of the Kasai River sand was obtained from cyclic tri axial tests.INTRODUCTIONThe term Liquefaction is used in conjunction with a variety of phenomena that involve soil deformations due to cyclic disturbance in saturated soil under undrained conditions. The generation of excess pore water pressure is the hallmark of all liquefaction related phenomena and the reduction in the volume or the tendency of cohesionless soil to densify during undrained loading condition as prevails during an earthquake is also well known. Use of shaking table tests to understand liquefaction of soils has been demonstrated by several researchers (Ye et al. 2013; Ha et al. 2011). Mohajeri and Towhata 2003 and Towhata et al. 2006 carried out 1-g shaking table tests on soil models prepared in laminar box to study the rate dependent behavior of liquefied soils. Ueng et al. 2010 used a biaxial laminar shear box mounted on shaking table to study the settlements in saturated clean deposits of sand and related the volumetric strain in liquefied sand to the relative density for various shaking durations and earthquake magnitudes. Maheshwari et al. 2012 reported increase in liquefaction resistance of reinforced sand through shaking table tests and concluded that the type and amount of reinforcement in the soil layer has influence on its liquefaction potential.The objective of the present study is to compare the behavior of dry and saturated Kasai River sand when subjected to seismic shaking. The Kasai River separates two growing cities, Medinipur and Kharagpur in the state of West Bengal in India. A number of road and railway bridges exist over the river connecting the two cities. The area being in Seismic Zone III, that is, a zone with moderate probability of earthquake, it is important to characterize the behavior of the Kasai River sand during a possible earthquake event especially when a number of bridges are existing over it. Small scale laboratory model tests and numerical analyses using a commercial finite difference algorithm called FLAC2D (Itasca 2005) have been utilized to study the difference in behavior of dry and liquefied Kasai River sand during dynamic loading conditions."

Jan 1, 2015

By Guilherme L. M. G. Carvalho, Zachary T. Fleming

In a world of 2-dimensional design documents, envisioning and understanding 3-dimensional interferences for complex foundation construction scenarios can be challenging. Videos and computer models serve as 3-dimensional spatial aids but have drawbacks related to a fixed perspective. Augmented and virtual reality (AR/VR) provide new tools to communicate design challenges and improve construction planning. This paper provides a practical look at the basics of AR/VR systems and the tools available to the foundation design and construction industry by giving a high-level example of the technologies’ use in the design and delivery phases of a complex micropile installation project for the remediation of a dam foundation. Using these technologies, GEI was able to design and deliver a complex foundation remediation solution. AR/VR benefited regulators, and the client, to help understand the design concept, construction sequencing, and approach to overcoming installation challenges. Due to its user-friendly nature and less rigorous programming and hardware requirements, AR proved to be more useful than VR for this scenario. AR/VR will likely not replace videos and computer models; however, it can be a useful 3-dimensional visualization aid that complements the project delivery process and offers benefits that traditional methods cannot. INTRODUCTION Augmented and virtual reality is a promising and rapidly developing technology within the engineering and construction world. Like any rapidly developing new technology, the language describing it can be confusing and dynamic. To eliminate the confusion some definitions must be made. AR/ VR definitions The definitions of virtual reality (VR) and augmented reality (AR) for the purposes of this paper are as follows: VR is a computer-generated immersive environment that the user experiences within a digital 3- dimensional space (Satava, 1993)AR is a composite view created by superimposing digital objects into the user’s real-world view (Azuma, 1997). Often, VR is used in an office environment and allows the user to “visit” the digital site to review site planning, construction sequences, and interference geometry. AR can be utilized in both the office and onsite environments. Like VR, the in-office application for AR is commonly site planning. AR also can be utilized in the field for applications such as seeing through the ground to locate known existing obstructions like utilities, gas tanks, etc.

Jan 1, 2019

By Lorie M. Dilley

Alaska Village Electric Cooperative (AVEC), an electric utility cooperative providing power to 51 Alaska villages, has made a concerted effort to install wind turbines in the villages they serve in an effort to mitigate the growing costs of electrical power generation. The subsurface soils in several of these villages consist of sands and silts with ground temperatures of between 30°F and 32°F. The presence of warm, degrading permafrost in three of the villages has required innovative foundation designs, including the use of helical piers and piles to support steel and concrete wind turbine foundations. The design of the deep foundations had to account for the effects of degrading permafrost likely resulting from observed climate change patterns. Uplift forces imposed on the foundations were approximately 100 kips per pile. Uplift pile load testing was conducted on the installed piers and piles in order to determine the actual working load that each pier or pile could sustain. In addition, pile driving analyzer testing was conducted on several piles installed in the permafrost and compared to pile load tests. Results indicated that the installed piers and piles achieved the necessary capacity with sufficient factors of safety. Thermosyphons were installed near the foundations in order to limit the effects of climate change on the permafrost. The two to four wind turbines in each of the three villages are currently operational. Refinement of the design based on the pile testing from the first village to the third has decreased the cost of the tower foundations and improved our understanding of designing for warm, degrading permafrost.

Jan 1, 2010

By Mark Spence, Tom Lardner, Matthew Janes

"IntroductionThe design-build method streamlines project delivery through a single contract between the Contract manager and the design-build team. The design-build method places emphasis on collaborative project management between design and construction disciplines to minimize project schedule, reduce costs, encourage balance risk amongst the design-build team. Since 1985, the percentage of nonresidential design and construction projects has increased from 5% to 45%.1A project carried out in Edmonton, Alberta, Canada will be used as an example to illustrate the challenges of the design-build project delivery method and the merits of establishing a GBR. The project involved a complex slope stabilization as part of an extensive freeway widening. At the project location the roadway was being widened within the base of a historic stream valley into a steep slope with a history of a previous slope failure. The slope was to be steepened through the installation of a series of 14 interlocking arc structures constructed half way up the slope. Access and schedule proved critical to the successful completion of the project.Geotechnique and Site HistoryThe geotechnical investigation undertaken for the site included six boreholes drilled at the crest of the slope to depths ranging from 14.5 m to 30.2 m. Laboratory testing of the soil samples included direct shear tests, Atterberg limits and grain size analysis. The geotechnical report also referenced a previous geotechnical investigation that was carried out in response to a failure of the slope in 1971."

Jan 1, 2015

By Leykam Chris J., Jacobs Scott. A.

"Construction of the New NY Bridge over the Hudson River 25 miles north of New York City is one of the largest civil infrastructure projects presently underway in the United States (formerly Tappan Zee Hudson River Crossing). The $3.14 billion Design-Build contract is also the largest ever awarded by the state of New York using an Alternative Project Delivery method, and the first major public project to use Design-Build. The new 3.1 mile long bridge will replace the existing Governor Malcolm Wilson Tappan Zee Bridge with a modern twin crossing featuring: Iconic side by side cable stay main spans; significant deck widths accommodating eight lanes of regular traffic, wide shoulders, and a shared use pedestrian and bike path; foundation with excess capacity to fully support a future rail bridge; more than 1,000 large diameter pipe piles driven in deep glacial deposits; drilled shafts installed through steep blast-rock slopes on the east shore landings. Geotechnical challenges included varied bedrock and glacial till surfaces with steep slopes and depths in excess of 750 ft.The purpose of this paper is to highlight major features of the New NY Bridge project with specific focus on the design and construction of the foundations supporting the approach and main span structures from abutment to abutment, provide background on alternative project delivery in NY, as well as provide an overview of the design-build process as it was applied to foundation delivery.The 3.1 mile Governor Malcolm Wilson Tappan Zee Bridge was constructed across the Hudson River connecting Nyack and Tarrytown (Rockland and Westchester Counties). Construction started in March 1952 and was completed in 1955 for a cost of $81 million. The seven lane crossing first opened to traffic on December 15, 1955 and coincided with the opening of a 28 mile segment of highway I-87 / I-287 between Suffern NY and Yonkers NY. The bridge is part of the extensive 574 mile New York State Thruway road system owned and operated by the New York State Thruway Authority (NYSTA)."

Jan 1, 2016

By Caciola Jr. Joseph J., Nidal M. AbiSaab

"Thanks in great part to the geology of the New York City Metropolitan area, mini-caissons are a popular choice for deep foundations. These drilled elements are readily available, easy to install with minimal impact on adjacent structures, and can be designed with large compressive and tensile capacities. Despite the frequency with which they are employed, the engineering design community is divided over several of the underlying principles governing the design of mini-caissons. This paper seeks to draw attention to several of these issues in an effort to encourage further research and discussion, namely: (1) how the allowable stresses have changed for the NYC Building Code over time, (2) the inconsistent load transfer mechanisms considered for geotechnical capacity, and (3) the role of the permanent steel casing towards structural capacities of mini-caissons.INTRODUCTIONIn the local construction nomenclature, mini-caissons are drilled deep foundation elements which derive their capacity from a socket in rock. A permanent steel casing (commonly between 7- and 24-inches in diameter) aides the drilling through overburden soils to the top of bedrock. Afterwards, an uncased rock socket is drilled into the bedrock and the inside of the casing and rock socket is inspected by means of portable video equipment. After inspection, the interior of the socket and casing is filled with steel reinforcement and concrete or grout. The casing-soil interface is generally ignored for axial design purposes and the full geotechnical compressive or tensile capacity is assumed to be generated in the rock socket. Figure 1 shows a typical mini-caisson cross section.Mini-caissons have been used for decades in the New York City area for a number of reasons. They have historically been proven to develop high axial capacities in the city’s metamorphic rock (Tamaro et. al. 2000), often exceeding 300- to 500-tons. Additionally, their method of installation (drilling) is generally able to bypass layers of dense Glacial Till, boulders, and manmade fill which would interfere with the installation of other pile types (e.g. driven piles, auger cast piles). Further they are able to extend to depths exceeding 50-ft to reach bedrock underlying a site, making them a useful tool in areas where rock is relatively deep or varied in elevation. Drilled casing installation also results in fewer vibrations and disturbances to adjacent structures and can occur in areas of restricted access (a constant concern for any project in a dense urban environment such as NYC)."

Jan 1, 2016

By Phillip E. Glogowski, N. Catherine Bazan-Arias

Steel foundations can be designed to cross-sectional configurations ranging from triangular and square to other multi-side shapes. Adding lateral extensions (hereby called wings) along the length of the steel stem can increase the foundation’s uplift, torsional and lateral load capacities. DiGioia Gray staff developed a methodology for the optimal design for multi-facetted, winged deep steel foundations. A finite element (FE) model is used to represent the steel components and the nonlinear subsurface behavior. The geometry of the foundation can be complex; thus, an optimal design needs to be fine-tuned to the specific site conditions. We created a pre-processor tool to generate the FE model including varying values for the number and size of wings, depths of embedment, reveal/stickup heights, top plate geometries, and subsurface profiles. The analytical model has been partially validated through full-scale testing and the methodology has been applied to two installed projects to date.

Sep 8, 2021