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By A. B. Cerato, M. K. ElSawy, A. Elgamal

"Helical piles are gaining popularity as foundations for new construction as well as retrofitting option for deficient foundations. More recently, large diameter helical piles are used to support structures in regions characterized with high seismic hazard. Even though they have proven to be viable in seismic areas such as New Zealand, where they experienced little damage during the Christchurch earthquake, the knowledge about their seismic analysis and performance is largely lacking. Therefore, there is a need for comprehensive study to evaluate their performance under seismic loading. The current objective of this study is to investigate the performance of helical piles through a full-scale testing program that was performed at the NEES/UCSD Large High Performance Outdoor Shake Table (LLHPOST). The experimental setup involved ten steel piles of different configurations installed in dry sand. The piles were loaded with different masses and were subjected to different earthquake signals to simulate different dynamic behavior. This paper compares the performance of different moment curve fitting methods used to interpret the test data. Furthermore, the effects of different frequency content of loading on the pile response is illustrated in terms of deflection along the shafts of tested piles with different configurations.INTRODUCTIONEarthquakes are a major hazard for structures situated in seismic regions, and dynamic loading must be a design consideration. Successful design of a foundation system entails providing a safe and economic foundation solution to resist earthquake loading. Different foundation options have been used to support buildings in high seismic regions. Helical piles represent a viable foundation option that offers several advantages in terms of ease of installation, lower cost and environmental impact, ability to approximate the axial capacity directly from torque readings and more (Perko 2009). However, they are not typically considered as an option in many seismic regions. Meanwhile, several buildings supported on helical piles in New Zealand have survived the Christchurch earthquake with negligible damage, which encourages performing further research to understand the behaviour of these piles under seismic loading.A helical pile consists of a steel shaft fitted with a steel helix/helices. The helical pile is installed by applying torque to its head via mechanical torque. Nowadays, helical piles are used in a wide range of applications such as foundations for light posts and residential houses. The static behaviour of helical piles has been studied extensively and is relatively well understood (Tsuha and Aoki 2010; Mittal et al. 2010; Sakr 2011; Elsherbiny and El Naggar 2013; El Sharnouby and El Naggar 2012; Elkasabgy and El Naggar 2015; Weidong et al. 2015 and Bagheri and Naggar 2015) However, the dynamic and seismic behaviours of helical piles is seldom investigated (Elkasabgy and El Naggar 2013). This underscores the knowledge gap currently present regarding the seismic behaviour of helical piles."

Jan 1, 2017

By James L. Christensen, Gregory Sanchez, Michael P. Walker

The Fogg Museum expansion project required excavation and construction in a congested urban area in Cambridge, Massachusetts. A soldier pile tremie concrete (SPTC) wall provided the support of excavation and now serves as the permanent basement wall of the new expansion of the museum. The existing Fogg museum had a single basement level. The new expansion has a two-level basement for new exhibit space and an amphitheater. The east side of the site is about 20 feet above the basement level of the existing Fogg structure which resulted in a significant unbalanced load that needed to be resolved without damaging the original Fogg structure. The SPTC wall was supported with a combination of tiebacks and internal bracing. The final depth of the excavation was about 40 feet below street level. Strict movement control was imposed because the existing museum contained an Italian Renaissance-style courtyard. The southeast corner of the SPTC wall had to accommodate underpinning of an historic concrete ramp which was ultimately incorporated into the expansion. Challenges during construction included excavating the SPTC wall panels up to 12 feet into argillite bedrock which had occasional diabase dikes and sills. The following topics are discussed in more detail after a general project.

Jan 1, 2015

By Peter Cali, Wesley Schmutzler

"The Deep Mixing Method (DMM) was employed to raise and support the LPV (Lake Pontchartrain and Vicinity) -111 Levee in New Orleans. Even using innovative technologies, the tight schedule to achieve the 100 year elevation by June 1, 2011 was a daunting endeavor. The size and scope of DMM proposed for LPV-111 was on a scale never attempted outside of Japan. Over 1.65 million cubic yards of DMM was installed. LPV-111 is adjacent to the Bayou Sauvage Wildlife Refuge, which is the largest urban National Wildlife refuge in the United States. By utilizing DMM to control settlement and improve stability of the taller levee, side slopes were steepened from the conventional 1V:4H to 1V:2.85H, thus avoiding encroachment into the Bayou Sauvage and reducing the amount of clay needed for the completed levee. The COE utilized Early Contractor Involvement (ECI) for this contract. The ECI process allowed for input from the DMM contractor, TREVIICOS South, in order to optimize equipment resources and material requirements. This paper gives an overview of the extensive DMM requirements for LPV-111 and explains the benefits of the ECI process.IntroductionDuring hurricane Katrina the levee that constitutes LPV-111 was overtopped and breached in several locations. The United States Army Corps of Engineers (USACE) was presented with the task of increasing the level of the flood protection around New Orleans after Hurricane Katrina to the 100- Year hydraulic grade - the level of protection that provides risk reduction from a storm surge that has a 1% chance of being equaled or exceeded in any given year - and the firm project completion deadline was June 2011.LPV-111 is located in East New Orleans and a large portion of the levee is adjacent to the Bayou Sauvage National Wildlife Refuge. The levee could not encroach on this area. This provided a limited footprint for the levee and made construction of conventional levee difficult, if not impossible. The total length of the project was 5.3 miles. Included in the project was the rehabilitation of one main pumping station and one smaller pump station for water management within the refuge. Short sections of “T” wall were used at the tie in at the Lake Borgne Surge Barrier, the main pump station and the CSX Railroad crossing"

Jan 1, 2017

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 Suzanne R. Hess-Brittelle, Sharon L. Schulz, Tyler J. Quick, Amy F. Ebnet

"Abiquiu Dam is a rolled earth fill dam with impermeable core located on the Rio Chama in New Mexico. Abiquiu has had a history of excessive seepage through the fractured sandstone abutments since water was first impounded in 1963. The foundation was treated with a single row grout curtain in the cutoff trench prior to placement of the embankment. During the 1960’s and 1970’s, the grout curtain was extended 1,000 ft. into both abutments and sections of the foundation beneath the embankment were regrouted. Grouting of the foundation beneath the embankment required drilling through the embankment. Drilling fluid loss or loss of circulation within the impervious core was observed during multiple phases of supplementary grouting and during verification drilling following the 1970’s grouting program. It is likely that the drilling methods employed for these grouting and drilling programs caused hydraulic fracturing of the impervious core. The fluid losses in the embankment may be related to seasonal shutdown layers in the embankment or benches in the abutment foundations. In addition, it is likely that the impervious core was fractured from grout pressures during installation of grout pipe through the embankment.INTRODUCTIONAbiquiu Dam is located on the Rio Chama in New Mexico and consists of a rolled earth fill dam with impermeable core, controlled outlet works, and an uncontrolled rock-cut spillway. The dam was authorized for flood control and sediment retention and was designed as a dry dam, holding flood pools for relatively short durations. The foundation is comprised of Permian and Triassic age, interbedded mudstones and sandstones that were deposited in an active braided stream system. Sandstones are moderately fractured and have variable aperture and infilling. Generally speaking, joints are near vertical. Abiquiu has had a history of excessive seepage through the fractured sandstone abutments since water was first impounded in 1963. The foundation was treated with a single row grout curtain in the cutoff trench prior to placement of the embankment. In 1966-1968, the grout curtain was extended 500-ft into the left abutment and the foundation beneath a 560 ft. section of the embankment was re-grouted. In 1978-1980, the grout curtain was extended 1,000 ft. into the right abutment, an additional 500 ft into the left abutment and the foundation beneath the right 520-ft section of the embankment was re-grouted. The alignments of these grout programs are shown in Figure 1. Grouting of the foundation beneath the embankment required drilling through the embankment. Drilling fluid loss or loss of circulation within the impervious core was observed during both phases of supplementary grouting and during verification drilling following the 1978-80 grouting program. It is likely that the drilling methods employed for these grouting and drilling programs caused hydraulic fracturing of the impervious core. In addition, it is likely that the impervious core was fractured from grout pressures during installation of grout pipe through the embankment. This paper provides a summary of the drilling and grouting methods used during these programs and the potential for damage to the embankment."

Jan 1, 2016

By Mohammad Ali Rowshanzamir, Mehdi Aghayarzadeh

"This article is an effort to improve our understanding of the performance of geogrid retaining structures (GRS) through numerical analyses. The numerical modeling utilized a commercially available finite difference program, FLAC3D. In this context an extensive parametric study has been carried out on two different GRS walls (vertical reinforced block and inclined reinforced block) to investigate the influence of internal design factors such as soil strength properties and reinforcement stiffness on the performance of these walls. The main purposes of the parametric study were to (1) investigate the sensitivity of the modeling results to the input material properties, (2) examine the influence of the internal design factors on the performance of GRS retaining structures, and (3) improve the internal design of GRS walls on the basis of the working stress information obtained from the parametric study. Based on the analyses results, it was revealed that GRS walls with oblique reinforcement and reinforced block (rotated against natural backfill) have much better performance in terms of reduction in the stresses and strains of reinforcing elements as well as decrease in the wall lateral and vertical displacements in comparison with vertical reinforced block (conventional wall). For example, with 12° inclination of the wall reinforced block there was 50% reduction in the backfill settlement. Also increasing the reinforcement stiffness amount from 10MPa to 50MPa decreases the wall face displacement more than 50% in both GRS walls.INTRODUCTIONOver the past few decades, Geosynthetic- Reinforced Soil (GRS), a soil mass reinforced by geosynthetic layers to restrain the soil lateral deformations, has been employed in the construction of many types of earth structures, including retaining walls, embankments, slopes and bridge abutments. In fact GRS structures are typically more flexible (hence more tolerant to differential settlement), more adaptable to low quality backfill, easier to construct, require less over-excavation, and more economical. Nevertheless, there is a need for an accurate design tool that can predict the performance of GRS structures under working stress conditions and can predict their failure loads as well.Many studies have been published on the performance of the soil reinforced walls such as Isabel et al., 1996; Bathurst et al., 2000; Kazimierowicz-Frankowska, 2005; Nernheim and Bathurst, 2008; Chen and Chiu, 2008 Correia et al., 2012; Erlich et al. 2012. Several numerical studies have also been made throgh finite elements and finite difference techniques on reinforced soil retaining walls to analyze the wall deformations (e.g. Hatami et al. 2001& 2006, Liu and Won 2009, and Abdelouhab et al. 2011). A limited laboratory research has been reported indicating of improving effect of tilting face on GRW performance (Chen and Chiu, 2008). However no major numerical study was found on the effects of face or reinforcement tilting."

Jan 1, 2017

By Dennis Nottingham

"Increased interest in seismic soil liquefaction and preventative soil stabilization sets the stage for improved deep compaction methods using pile driving techniques. In 1971, L.B. Foster Company personnel patented a method of deep compaction using a vibratory pile hammer and pile probe. The technique had some success, but did not produce consistent results and thus found its way to obscurity. Other patents attempted to modify the technique by various probe modifications, but again without measurable improvement from a practical point of view. Solutions to economical deep compaction up to 100-foot depths particularly in saturated granular soils would have a great impact on the construction industry and new bulkhead structures being developed, thus PND was prompted into related research and development. The advent of higher horsepower vibratory hammers, coupled with PND engineers’ experiments, observations and measurements, led to an “H” pile probe design which has produced measured soil density improvements up to 250% using SPT “N60” values as a measure. Case histories of two projects involving extensive SPT soil sampling comparative measurements will be discussed along with findings that led to the compaction success. Applications to numerous modern “Open Cell” bulkhead projects will be presented and discussed.INTRODUCTIONNecessity often is the basis for innovation and such was the case for needed cost-effective deep soil fill compaction in Open Cell bulkheads where granular fill below water levels was often placed.Open Cell bulkheads were developed by PND Incorporated starting in 1980, for the express purpose of meeting client demands for an economical, easily constructed, extremely strong structure. Earth-filled structures historically have had a long history of problems with stability, scour and settlement.Open Cells are flexible steel sheet pile membranes supported by soil contact with embedded tail anchor walls.This concept creates an integral reinforced soil system. The result is a structure that can withstand large settlement and support a variety of very large loads. In effect, viewed from above the structure becomes a series of U-shaped horizontal membranes that require no toe embedment for stability. The Open Cell bulkhead is constructed of only three components: flat sheet piles, fabricated connector wyes and anchor piles. Compared to alternative structures, several cost savings are realized from this land based construction such as, reduced sheet pile area, greater construction tolerance, minimal pile penetration, and simplified backfilling procedures. In seismic regions or weak soils, the tail walls can be extended as required to guarantee fill mass stability."

Jan 1, 2005

By Shawna Munn, Carol Dounitch, Erika Acton

The EQ Bank Tower, a 24-storey office tower with 4 levels of underground parking, is currently under construction at 25 Ontario Street in the downtown core of Toronto, Canada. The tower geometry required an 18 m (60 ft) deep excavation inside an existing 3-storey 100-year-old façade, to be retained in place throughout construction. This presented a variety of design challenges that required several innovations and a customized monitoring program. In this paper, we will discuss two major challenges, and highlight the innovative and adaptable solutions carried out using performance-based design leveraging the observational method. The first was installation of a shoring system in a 500 mm (20 in) gap between the historical façade and a live gas main. The second involved excavating 10 m (33 ft) into expansive shale bedrock adjacent to a sensitive neighbouring building.

Oct 1, 2022

By Thomas G. Tavernaro, Jeffrey A. Schaefer

"The $106 million Olmsted Approach Walls Project, completed in the spring of 2004 by Massman Construction Co., Kansas City, MO, is one phase of a new $1.4 billion Corps of Engineers locks and dam facility located at Mile 964 on the Ohio River, approximately 17 miles (27.4 km) upstream of its mouth at the Mississippi River. When completed, the Olmsted Locks and Dam (Figure 1) facility will replace two aging locks and dams (Locks and Dams 52 & 53) built in the 1920’s, and produce an estimated $600 million annual economic benefit to the nation through reduced lockage time and operation and maintenance costs. PROJECT OVERVIEWThe Olmsted Approach Walls Project consisted of “in-the- wet” construction of four fixed nose pier structures, four floating concrete approach walls, one fixed wall and related underwater excavation, grading and stone placement. Over 12,000 tons (11,000 tonnes) of structural steel and pre-cast concrete elements, up to 335 tons (304 tonnes) in weight, were safely erected during the project.To support these massive structures, the Louisville District of the U.S. Army Corps of Engineers teamed with INCA Engineers, Inc., Bellevue, WA to design thirty seven 10’ (3m) diameter shafts (cast-in-place steel-shell piles) capable of maintaining elastic behavior below ground while resisting barge impact loads, extreme head-on collisions from runaway tows, and environmental forces from river current, wind, and seismic events.The shafts (typically 150’ (45.7m) in length) were founded 100’ (30m) into the riverbed through alluvium, a very consolidated fine sand and clay Cretaceous soil, and finally into a hydrothermally altered rock. Thirty seven shafts were installed under open river conditions at the site, a group of four shafts at each nose pier-pylon location (Figure 2), and 21 at the fixed land wall. Due to difficulty in achieving the required casing tip elevation the team developed a design modification that was successfully implemented for 27 of the shafts.Concurrent with the work at Olmsted, eleven pontoon segments for the four floating approach walls were constructed at a graving yard in Paducah, KY, developed by Massman Construction Company specifically for the project. While the pontoon geometry varied, the pontoons averaged 350’ (107m) in length, 40’ (12.2m) in width and weighed 4,500 tons (4,082 tonnes). The longest of the four walls, at 1,700’ (518m) was comprised of five interconnected pontoons."

Jan 1, 2006

By Douglas L. Scaggs

Driving piles in under water applications has become more common place over the past twenty years. Where only a water depth reachable with a follower or dewatered cofferdam was the rule in the past, newer technologies developed for the offshore oil and gas industry have made depths of even several thousand feet possible offering new possibilities in foundation design and installation. With the new technology, engineers can now more efficiently design structures by placing foundations optimally thereby reducing weight and cost of the overall structure.

Jan 1, 2013

By Darrell L. Beddard

The test program information provided for some immediate changes on the upcoming contracts and in contract administration for the I-880 Replacement Project. Plan sheet modifications included changes to the pile data tables showing the actual demand load required for structural stability. The normal class of pile with a minimum load carrying capacity was removed. This provided for substantial pile length reduction at several locations since the structural loading was much less than the predetermined pile class ultimate capacity. New specifications were developed and standard specifications were modified to accommodate the newer foundations, installation procedures and pile acceptance criteria. Current Caltrans specifications require that the Contractor provide bearing capacity at the specified tip elevation. This requirement was removed and pile acceptance was determined by the Engineer. Acceptance criteria was established by the State and was based on. set-up trend over time. Static loading tests were reduced especially in areas where testing was performed on the indicator program. Testing procedures were modified and set-up periods were established before piles could be tested. For the contract near the San Francisco Oakland Bay Bridge (Unit E) the FHWA 1000 tons (8.9 MN) test beam configuration was completely changed. This provided added safety and allowed more tolerance in the pile placement for the testing operations. Indicator piles were added as companion piles to the static loading test piles. These piles were used for restrike events which included collecting dynamic data for calibrating the wave equation analysis with static load test results. Indicator piles also provided quick access for restrike events, where as, the static loading test pile needed modification to perform the restrike operation. Penetration rates were recorded for these operations. Wave equation Analysis Program (WEAP) was used in developing the acceptance criteria. The standard Engineering News Record (ENR) formula in the current Caltrans' Standard Specifications was removed for the contracts. Contractors were required to submit, prior to driving piles, a driveability study for their contract. These studies required discussion of their operations, method of installation, effects of soil set-up, set periods, hammer settings, bearing graphs, inputs to the WEAP program and complete a "Pile and Driving Equipment Data" form. Dynamic monitoring was detailed in the specifications on how the monitoring process was to occur. Set periods were established and restrike events were called out with the frequency of these events.

Jan 1, 1996

By Rajarshi Pramanik, Nirjhar Dhang, Dilip K. Baidya

"This paper performs the reliability evaluation of pile foundation under vertical loading condition using the concept of fuzzy set theory. The uncertain parameters are expressed as fuzzy numbers. Monte Carlo simulation technique in conjunction with fuzzy set theory and fuzzy reliability index approach are implemented in evaluation of the probability of failure of pile foundations. The results are validated through some well established methods such as, First Order Reliability Method (FORM), Second Order Reliability Method (SORM), and direct Monte Carlo Simulation (MCS). Response surface method (RSM) is used to approximate the original limit state equation through second order polynomial. The effect of the position of the water table is also highlighted. Finally, the effect of the variation of applied load is examined and it is observed that the fuzzy reliability analysis gives more conservative estimate of failure probability than the other methods.INTRODUCTIONCivil engineering structures, such as high rise buildings, bridges, offshore platforms etc. are always subjected to vertical as well as horizontal loads. To support these structures, pile foundations are generally the solution in most of the situation. It transmits load from the superstructure to soil at a reasonably great depth. This transfer may be by vertical distribution of the load along the pile shaft or a direct application of load to a lower stratum through the pile tip. Different methods are available to estimate the capacity of piles embedded in different types of soil and under the application of vertical and horizontal loading. To consider the variability in soil and other unforeseen able situation, generally a reasonable value of factor of safety is used to estimate the designed capacity of the pile. Recent developments have shown a trend to place the treatment of uncertainty on a more formal basis, in particular by applying the results of reliability theory to geotechnical engineering. Keeping in mind the importance of pile foundation in the engineering structures it is essential to maintain a high structural safety which result in increase in reliability. The probability theory has been proved to be a powerful tool for representing variability in mathematical models. The variability associated with soil parameters and the modeling uncertainties are needed to be considered for the reliability assessment purpose.Recent development (Zhang et al. 2005; Misra and Roberts 2006; Haldar and Babu 2008; Basu and Salgado 2012; Teixeira et al. 2012; Pula and Rozanski 2012; and Chan and Low 2012) showed that the reliability analysis of pile foundations subjected to axial as well as lateral load has been one of the important current research topic in geotechnical field. Probabilistic based performance criteria were quantified for a single pile and pile groups in cohesionless soil by Eloseily et al. (2002). A p-multiplier approach was incorporated into the analysis to modify the p-y curve for a single pile to obtain the p-y curve for individual piles in a pile group. A statistical analysis of set up capacity of pile was carried out from the database of a large number of pile testing data in clay by Yang and Liang (2006). Load and resistance factor design (LRFD) using FORM was used for examining the different load and resistance factor for different target reliability index. Limit state analysis of drilled shaft was performed by Misra and Roberts (2006) in probabilistic framework. The fuzzy based reliability analysis (Dodagoudar and Venkatachalam 2000; and Park et al. 2012) of the earth slope was reported in the literature. Dodagoudar and Venkatachalam (2000) presented a new approach, called fuzzy point estimate method (FPEM) for reliability evaluation of earth slope. Park et al. (2012) reported a hybrid approach, fuzzy set theory in conjunction with Monte Carlo simulation technique, to determine the failure probability of earth slope. Second Order Reliability Method"

Jan 1, 2015

By Jeremy G. Kress

We propose the discrete element method (DEM) as a complimentary alternative to analytical solutions and FEM models for the analysis of pile response. DEM is a novel approach to the engineering design of deep foundations which can be used to provide insight into the mechanics of soil-soil and soil-structure interaction. It is common to use analytical, empirical, and semi-empirical methods to predict pile behavior, where if granular properties, pile length, or load orientation change, then significant adjustments are made in the design sequence. DEM provides a more uniform approach in granular soils. Based on constitutive force-displacement relationships and laws of motion in rigid and elastic bodies, few changes must be made for a wide variety grain types, pile types, embedment, and load orientation. Preliminary results for simulation of a single pile are qualitatively consistent with results from conventional design procedures and also provide significant information not available from other analyses (e.g., local information about interface failure during shear). Importantly, these analyses are portable to a variety of pile types and installation procedures, which may not be the case for empirical approaches. Given consistent increases in computing power and rapid advances in model speed and sophistication, the DEM should prove to be a robust method for design and the analysis of pile response in granular soils.

Jan 1, 2010

By Lawrence F. Johnsen

Six case histories are presented in which tall, slender high rises are supported on high capacity minicaissons. The recent development of a high strength rebar cage has resulted in compressive loads of up to 3400 kips on 24 inch diameter minicaissons. Provisions in the pending NYC building code will allow borehole video inspection in lieu of load testing. The ?new? technology results from the marriage of several well established methods: rotary duplex well drilling, high capacity micropiles and high capacity reinforced concrete building columns.

Jan 1, 2007

By Slav Tchepak

The King's Wharf development is located in Sydney's Darling Harbour area. The site was originally used for industrial maritime purposes, which over the years has been reduced to accommodating leisure craft only. The site has been filled with various materials, resulting in fill materials varying from soils, to concrete and rock fill. A prestigious new residential development at the site required piles to found in Sydney sandstone that occurred at depths ranging from 1 to 27m. The selection of appropriate pile types is discussed, as are details relating to the design and construction of cast insitu Omega piles and CFA piles. A number of issues needed to be addressed relating to the piling, including the design of the piles, the potential for liquefaction of the fill material due to earthquakes, penetration of the piles through the fill materials, installation of the piles to a satisfactory positional tolerance and pile performance. A number of piles were dynamically tested to prove pile performance and these results are presented and compared with design expectations. The project was successfully completed on time and budget, indicating the selection of pile types in the difficult ground conditions to be appropriate.

Jan 1, 2000

By Ryan Sullivan, Lisa Smiley, Jewels Stover

The Westerly Storage Tunnel (WST) Project is part of Project Clean lake, the North East Ohio Regional Sewer Dist years. When completed in 2020, WST will be nearly 2 miles of 25-ft diameter tunnel 200-250 ft below ground. The storage tunnel will manage higher flow volumes, keeping stormwater out of the combined sewer system reducing overflow occurrences. Three deep shafts provide access to the tunnel at the tunnel boring machine (TBM) launch and retrieval sites, as well as a vent shaft. Support of excavation for the access shafts was constructed utilizing unreinforced concrete diaphragm walls. This innovative, value-engineered alternate design significantly reduced risks associated with conventional secant piles combined with a rib and liner plate system. Implementation of the diaphragm wall technology resulted in a water tight, continuous shaft keyed into rock. This case study examines the design, methodology, and installation challenges unique to each shaft, as well as the benefits of the final product to the overall project.

By Douglas L. Scaggs

Over the past several years, pile foundations have grown to meet the demands of larger and heavier structures. As the foundations have grown, so has the need for larger and more robust piles to carry the increased loads. Seismic considerations have also required larger and tougher piles to withstand the added component of supporting structures during earthquakes. While H-piles, precast concrete piles, timber piles and small pipe piles have been the product of choice, many applications are now calling for much larger piling requiring larger equipment and presenting the contractor with new challenges. This paper is not intended to be a ?how to? guide as much as a discussion on the potential pitfalls a contractor should watch out for when considering a project where mega piles are required.

Jan 1, 2013

By Moritz Schleeh, Christian Moormann

Temporary working platforms are generally required in order to ensure that heavy construction machinery such as drilling and trench wall units, pile drivers, vehicle and crawler cranes can be set up safely at the site of operation. Considering all possible operating and loading conditions, especially on ground of low shear strength and stiffness, the design and construction of temporary mobile working platforms needs to be considered more as a serious engineering task than as a second order structure of minor relevance. Working platforms reinforced with one or several geosynthetic layers have proven to be especially effective with regard to stability, serviceability and durability but their design requests even more sophisticated approaches. Existing design models are often based on simplified assumptions and do not consider the complex interaction between construction machinery, working platform and subgrade. Non-monotonic loading as well as elastoplastic and time-variant deformation of cohesive subsoil can adversely affect the base layer system and the serviceability and stability of the construction machinery operating on it. In this context, there is a need for improvement of design approaches and their optimisation considering that there are no generally accepted design approaches or technical codes of practice available for the design of temporary working platforms. The present paper deals with the multifaceted and non-trivial interaction effects of working platforms investigated by model tests, field measurements and numerical simulations to develop a design approach that ensures a safe installation and operation of heavy plants on unstable ground.

May 1, 2022

By Robert B. Bittner

The new gated dam on the Monongahela River at Braddock, Pennsylvania, was built for the US Army Corps of Engineers using an innovative ?In-the-Wet? technology. A key feature of this technology involves construction of the foundations through the water and later mating the completed structure or a shell of the structure to the pre-installed foundation. This paper presents a description of the structure, its foundation, construction sequence and design details required to successfully implement this technology.

Jan 1, 2013

By Tracy Brettmann, Melis Sutman, C. Guney Olgen

"The use of energy piles for geothermal heat exchange has been steadily increasing during the last decade, yet there are still pending questions on their behavior during temperature changes. This paper focuses on the thermo-mechanical response of three full-scale energy piles installed in Richmond, TX. The behavior of test piles subjected to thermo-mechanical loadings was studied in situ with the aim of quantifying the thermal influence on the performance and capacity of energy piles. An extensive field test program, including conventional pile loading tests and application of heating-cooling cycles was conducted on the test piles during a period of six weeks. For thermal load applications, the heat exchanger fluid with maximum temperature of 113°F (45°C) and minimum of 47°F (8°C) was circulated in the geothermal loops placed at the center of the test piles. Optical fiber sensors, vibrating wire strain gages, thermistors and thermal integrity profile wires were installed to monitor the strain and temperature variations along the energy piles throughout the field tests. The strain and temperature profiles during heating-cooling cycles on the test piles under static loads and without a maintained load were monitored to investigate the effect of thermo-mechanical and pure thermal loads on the energy piles, respectively. Conventional pile load tests were applied before and after the application of thermal cycles. The results of the pile load tests are compared to evaluate the effect of temperature cycles on pile capacity.IntroductionEnergy piles are deep foundation elements designed to access and exploit the relatively constant temperature of the ground and its heat storage capacity for efficient heating and cooling of buildings. The deep foundation elements that are already in place for structural support are integrated with adsorber pipes to perform as heat exchangers connected to ground source heat pump (GSHP) systems. With the use of energy piles, the heat energy is fed into and withdrawn from the ground for cooling in the summer and heating in the winter, respectively.Energy piles present an innovative way to harvest near-surface geothermal energy and to provide lower carbon emissions, however, there are still pending question on their performance. During heating-cooling cycles, energy piles experience temperature changes, which result in expansion or contraction of the piles."

Jan 1, 2017