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By Arash Saeidi Rashk Olia, Dunja Perić

The increasing demand for renewable energy has attracted attention to energy geostructures as means of extracting clean geothermal energy from the ground. To further advance the understanding of soilstructure interaction in energy piles analytical solutions considering the self-weight of the pile were derived. These solutions were then incorporated in recently-derived thermomechanical weightless solutions to provide comprehensive analytical solutions for axial displacement, strain and stress in single energy piles. This was accomplished by comparing responses of energy pile under different loading scenarios that reflect presence and absence of the self-weight. Results of mechanics-based analysis revealed that the self-weight of energy piles embedded in stiff soils has no significant contribution to displacement, strain and stress that develop under thermo-mechanical loads. Overall, the significance of the self-weight contribution depends on the magnitude of thermal load as well as the soil-pile interface stiffness. The stiffness of end restraints imposed to the pile head and tip were also found to play an important role in contribution of self-weight in induced thermomechanical stresses in energy piles.

Oct 1, 2022

By Thomas L. Vande Voort

The strategic plan for bridge engineering issued by AASHTO in 2005 identified extending the service life and optimizing structural systems of bridges in the United States as two grand challenges in bridge engineering, with the objective of producing safer bridges that have a minimum service life of 75 years and reduced maintenance cost. Material deterioration was identified as one of the primary challenges to achieving the objective of extended life. In substructural applications (e.g., deep foundations), construction materials such as timber, steel, and concrete are subjected to deterioration due to environmental impacts. Using innovative and new materials for foundation applications makes the AASHTO objective of 75 years service life achievable. Ultra High Performance Concrete (UHPC) with compressive strength of 26,000 psi (180 MPa) and excellent durability has been used in superstructural applications but not in geotechnical and substructural applications. This paper explores the possibility of using precast, prestressed UHPC piles in future bridges. An H-shaped UHPC section, which is 10-in. (250-mm) deep with weight similar to that of an HP10×57 steel pile, was designed for constructability and economical reasons. Instrumented UHPC elements were cast to conduct large-scale field tests. In the field, two UHPC piles have been successfully driven in glacial till clay soil and load tested vertically. Test results, durability, drivability, and other material advantages over normal concrete and steel indicate that UHPC piles are a viable alternative to extend the life of bridge structures.

Jan 1, 2008

By Prasanta Paul, Aminul Islam

"Nhava Sheva (India) Gateway Terminal Private Limited proposed to construct a container terminal yard, comprising a back-up area at Jawaharlal Nehru Port Terminal (JNPT), Uran, Maharashtra. The proposed container terminal yard is located on a recent reclamation on the Thane Creek, which was developed by land-based reclamation method. The underneath soft marine clay was treated, using vertical band drains and placement of surcharge upon.Settlement of the reclamation during its construction was monitored using settlement plate installed at +4.8m CD elevation which was above the highest high water level.This paper examines the settlement behaviour of the reclamation during the ground improvement works. The geotechnical parameters are back-analyzed by the authors from the field settlement results and the concerned preloading details. The back analyzed coefficients of consolidation due to horizontal flow (Ch) are compared with laboratory determined parameters and the estimated value, using Asaoka Method (1978). The authors also studied field compression ratio [CR= Cc/(1+e0)] vs. the compression ratio determined by laboratory test using back-analysis method.1. INTRODUCTIONNhava Sheva (India) Gateway Terminal Private Limited proposed to construct a container terminal yard, comprising a back-up area of approximately 27 hectares, complete with associated buildings and services on a part brownfield/ greenfield site. The back-up area shall include a heavy duty block paved pavement with band beams for electric Rubber-Tyred Gantry Crane (eRTGC) alongwith surface water drainage system and other services including area lighting, provision of fire-fighting facilities , sources for potable water and power.Based on the Employer’s Requirement and the available geotechnical investigation report, ground improvement scheme is designed by the construction contractor. Ground improvement works included the installation of prefabricated vertical drains and subsequent placement of surcharge for accelerating the consolidation of the underlying soft marine clay."

Jan 1, 2015

By Alper Turan

The use of aggregate pier foundation systems has become widespread as the engineering practice moves towards cost-effective ground improvement solutions that provide accelerated construction schedules. Increased bearing capacity, effective settlement control and potential for liquefaction mitigation are commonly acknowledged benefits of aggregate piers. This paper studies the mechanisms by which aggregate piers interact with each other and with the surrounding ground when excited by seismic loads. A particular emphasis was placed on the response of a raft foundation supported on a site improved using aggregate piers. Three-dimensional nonlinear finite element analyses were conducted using commercial software package, ABAQUS. Non-linear soil behaviour is modelled using a three-dimensional total stress-based bounding surface plasticity model, which is able to simulate stiffness degradation and damping increase in the soil. The soil stratigraphy considered in this study was a 30 m deep soil deposit that comprised a very stiff base layer and a shallow soft surficial clay layer. Ricker Wavelet time histories with different frequency contents are used as the excitation force in the analyses. Various area replacement ratios (ARR) for aggregate piers are studied for a square plan layout. The results presented in this study are considered to be of interest to researchers and designers in evaluating the seismic ground response of the sites improved using aggregate piers.

By Alper Turan, Hesham El Naggar

"The use of aggregate pier foundation systems has become widespread as the engineering practice moves towards cost-effective ground improvement solutions that provide accelerated construction schedules. Increased bearing capacity, effective settlement control and potential for liquefaction mitigation are commonly acknowledged benefits of aggregate piers. This paper studies the mechanisms by which aggregate piers interact with each other and with the surrounding ground when excited by seismic loads. A particular emphasis was placed on the response of a raft foundation supported on a site improved using aggregate piers. Three-dimensional nonlinear finite element analyses were conducted using commercial software package, ABAQUS. Non-linear soil behaviour is modelled using a three-dimensional total stress-based bounding surface plasticity model, which is able to simulate stiffness degradation and damping increase in the soil. The soil stratigraphy considered in this study was a 30 m deep soil deposit that comprised a very stiff base layer and a shallow soft surficial clay layer. Ricker Wavelet time histories with different frequency contents are used as the excitation force in the analyses. Various area replacement ratios (ARR) for aggregate piers are studied for a square plan layout. The results presented in this study are considered to be of interest to researchers and designers in evaluating the seismic ground response of the sites improved using aggregate piers. INTRODUCTIONThe schedule and cost limitations imposed by the traditional over-excavation and replacement method for the stabilization and settlement control for poor soils resulted are underlying factors for the significant increase in the use of aggregate pier foundation system, particularly in the last two decades. Various well known advantages of aggregate pier systems including increased bearing resistance, settlement reduction, and increased uplift capacity have been studied by various authors. The use of aggregate pier systems for settlement control in soft soil deposits was studied by various researchers including Lawton and Fox (1994), Lawton et al. (1994) and Wissmann et al. (2001). Lien and Fox (2001) studied the behaviour of aggregate pier systems supporting embankments and retaining walls. The stabilization of slopes by means of aggregate piers was studied by Lien and Fox (2001), Wissmann et al. (2002). Thompson et al. (2009) reported on a performance monitoring study of aggregate pier systems supporting MSE walls. The interaction mechanism between the aggregate pier system and the surrounding soil attracted attention of various researchers. Handy and White (2006a) and (2006b) studied the changes that occur less than 2 m from centers of the piers, and further away, respectively. The support mechanism of aggregate pier systems subjected to compressive loading were studied experimentally and numerically by White et al. (2007) and Pham and White (2007), respectively."

Jan 1, 2017

By Mark R. Svinkin

"Construction equipment and operations usually produce soil and structural vibrations which may harmfully affect various structures and also the content of buildings and houses. The level of structural vibrations depends on a number of factors such as characterized sources of vibrations, soil conditions, and susceptibility of structures. There are certain knowledge and experience for managing the effects of construction vibrations which require implementation of condition survey of structures, information on construction dynamic sources and soil conditions at a site, evaluation of possible vibration effects on structure, calculation of ground vibrations before construction, use mitigation measures to decrease vibrations, and a choice of appropriate vibration limits. The paper presents the application of known concepts for assessment of vibration effects on structures from bridge constructions.INTRODUCTIONVibrations producing by construction activities such as pile driving, dynamic compaction of loose soils, demolition work, heavy construction equipment and trucks can affect adjacent and remote structures. Vibration effects on structures, sensitive devices and processes may create significant practical problems. Legal actions are often required for solutions of vibration consequences. The level of construction vibrations depends on dynamic sources, soil conditions at a site in particularly availability of soils with settlement potential, distances from the sources, parameters of waves propagating at a site and susceptibility rating of adjacent and remote structures. It is likely that intolerable structural vibrations from direct vibration effects of impact pile driving and resonant floor vibrations from vibratory pile driving may be induced in adjacent structures to construction sites.Foundation settlements resulting from soil vibrations in loose soils usually occur in the proximity of dynamic sources, but it is important that dynamic settlement may happen at various distances from the source. There are such examples. First, Kaminetzky (1991) mentioned a case history of building settlements developed at a distance of about 305 m (1000 ft) away from a pile driving site. Foundations of the buildings were underpinned on piles down to the tip elevation of the new driven piles to prevent building settlements. Second, Lacy and Gould (1985) shows that the peak particle velocity (PPV) of 2.5 mm/s (0.1 in/s) of ground vibrations could trigger dynamic settlements at distances up to 30.5 m (100 ft) from driven piles."

Jan 1, 2016

By Michael Shedlosky, Sonia Sorabella Swift, Nina Carney, David Tarasovic

Rigid inclusions were used to support roadway fills and mechanically stabilized earth (MSE) walls for the South Capitol Street Corridor project. The first phase of this two-phase, nearly $1 billion project will include the replacement of the Frederick Douglass Memorial Bridge, including two approach ovals east and west of the Anacostia River, the replacement of the I-295/Suitland Parkway Interchange, and the construction of several traffic ramps. The bridge itself carries over 70,000 drivers daily and is expected to open in 2021. Ground improvement is required over a portion of the project footprint. Within the ground improvement area, the construction includes MSE walls up to 35 feet high and embankment fills up to 28 feet for which CMC rigid inclusions (RIs) were used to mitigate settlement and stability. The proposed construction runs over multiple old, in-service utilities that the project requirements indicate could not tolerate any stress or settlement due to the construction. As such, solutions that spanned the utilities were required. A concrete slab of varying thickness was used to span a fragile 108-inch-diameter sewer pipeline and 48- inch-square-precast-concrete box beams were used to span twin utilities that were buried just a few feet below current working grades on site. Unreinforced RIs were used to support these structures. The center to center spacing of the RIs perpendicular to the pipe run was 26.5 ft for the concrete slab and 62 feet for the precast--concrete box beams. The axial forces on the RIs were up to 267 kips. The RIs were not structurally connected to the slab or box beams. A single-element load test was performed to confirm the load-carrying capacity of the RIs. This paper will focus on the utility protection slab over the twin utilities and provide an overview of the design of the structural and geotechnical solutions and will present the results of the load test performed. INTRODUCTION The new Frederick Douglass Memorial Bridge (FDM Bridge) and reconstruction of the Suitland Parkway/ I-295 interchange (South Capitol Project) is a part of the Anacostia Waterfront Initiative (AWI) Program, whose goal is to transform the shores of the Anacostia River. The existing FDM Bridge is approximately 70-years old and has been classified as “functionally obsolete”. The completed South Capitol Project will improve the multi-modal transportation options, increase pedestrian and vehicular safety and provide additional green space. The proposed FDM Bridge, a rendering of which is shown in Fig. 1, is designed to become a landmark bridge in the Washington, D.C. area.

Jan 1, 2019

By Abid O. Adekunte, David Greentree, David Hilton

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

Jan 1, 2016

By Rick Deschamps

A reoccurring problem with support of excavations in urban areas involves the placement of external support components like anchors or nails in right-a-ways, subway and utility setbacks, in areas occupied by adjacent structures, and within the property of non cooperative neighbors. Such a situation occurred for a project in Arlington, Virginia, which ultimately resulted in the preliminary design of a large footing supported cantilever retaining wall that was extremely costly and impractical to build. An innovative design alternate consisting of a series of vertical concrete elements (VCEs) supported by post tensioned tiedowns was proposed to the General Contractor and accepted by the owner. The VCEs were designed to serve as the main structural elements for both the temporary support of excavation system and the permanent wall. The VCE?s were constructed using single bite diaphragm wall panels oriented perpendicular to the excavation face including a rebar cage and tremie concrete. Threaded inserts were placed within the rebar cage to attach the cast in place exterior wall. Overall stability and lateral movement of the VCEs were controlled by high capacity vertical anchors embedded within the VCE. A detailed instrumentation program was installed to monitor the movements of the VCEs with relation to the excavation depth. The paper present the project case history by discussing the design concepts of the VCE, the construction approaches used to install them, the construction challenges encountered, and the performance of the unique system.

Jan 1, 2008

"The Morris Island Lighthouse (MIL) is located between the jetties leading to the Charleston Harbor and Folly Beach, S.C. The present structure is the third lighthouse to occupy this location. The first navigational aid was erected in 1673, and consisted of a raised pan filled with pitch, which was set afire at night to guide early ships. The next structure was built in 1767, and constituted the first real lighthouse, standing 42 ft (12.8 m) in height. In 1838, a second lighthouse was built on the site, and it measured 102 ft (31 m) in height and featured a revolving light. This structure lasted until 1862 when Confederate troops, during the Civil War, destroyed it to deny its use to Union troops.Navigators steered these waters without a lighthouse for nearly a decade until 1876, when the current structure was built under the direction of the U.S. Army Corps of Engineers (USACE). In 1886, the Charleston area suffered a M7.6 earthquake. Significant damage was caused throughout much of the area, including a slight “list” of the lighthouse to the northeast. As a result, the cast of the beacon was reduced from 18 mi (29 km) to about 6 mi (9.7 km), causing much distress to navigators until the beacon platform was releveled and remains at this list to the present day.Conditions for ConcernThe current lighthouse was originally constructed about 1,200 ft (366 m) from the shoreline. Over the years, USACE has undertaken several programs to meet the increased shipping and navigation demands in the Charleston Harbor. Around the turn of the last century, two jetties were constructed, which drastically changed the approach direction for ships entering the harbor. In subsequent years, the harbor began to experience accelerated siltation."

Jan 1, 2017

By Jim Henry

I would say mainly the cost. I showed only 3 cases. One of them was the one that Allen just described and there were two other cases. In those cases it was fairly easy to develop a solution using limited mobility grout to treat the soft soils suitable for the limited bearing pressures required by the structures. LMG readily provided a fairly reliable system for the foundation support at a reasonable cost.

Feb 10, 2003

By Challa Venkata Rami Reddy, Anindya Roy, G. R. Konni

This paper presents the results of pile lateral capacities obtained from both conventional design and fullscale pile lateral load tests. Conventional design using P-Y curve analysis is very commonly being used by designers; designers use well accepted software programs like Lpile and Allpile for analysis. However, these programs do not cover the soil models to simulate engineering behavior of marine carbonate sands; which generally have different engineering behavior than silica/quarts sands. In this study, the existing soil models for common sands have been used to assess pile lateral capacities and these results are compared with the results from full-scale instrumented pile lateral load tests performed in compacted marine carbonate sand fills of artificial island constructed for oil and gas facilities in Abu Dhabi. The objective of this study was to verify the applicability of the existing sand soil models for carbonate sands and also to verify the associated conservatism in the pile lateral capacities. This study shows that the actual pile lateral response is much stiffer than what was anticipated through the LPile analysis. Therefore, further research focus may be required to capture the engineering behavior of the marine carbonate sands to develop specific P-Y curves.

Sep 8, 2021

By Drew M. Kurtz, Jeff L. Rai, Sara F. Frailey, Mohammad Ayub Iqbal

"This paper presents the foundation changes made for a five-span bridge over the Lehigh River constructed as a design-build project. During excavation within the cofferdam at Pier 2 for the construction of a spread footing to bear on rock, it proved extremely difficult to control the water entering the excavation as the sheet pile tips were variable due to the bedrock pinnacles and a weathered rock zone above the top of rock allowing water to pass below the sheeting. Water also entered from the bottom of the excavation, possibly due to the presence of solution openings within the dolomite bedrock. After repeated failures to achieve subgrade elevation and maintain a dry excavation, a design change to drilled shafts was made. Additional borings were performed for each of the shaft locations to explore the area underlain by karstic dolomite rock. A seal consisting of tremie concrete with adequate weight was placed to counter the differential head of water and the three drilled shafts (with minimum 25 feet [7.62 meter] rock sockets) were installed. A detailed construction sequence was followed and advanced quality control testing was performed. The construction of Pier 2 was completed successfully.1. INTRODUCTIONThis paper presents the description of the design change made from spread footing to drilled shafts as a result of site conditions encountered during the excavation for the spread footing for a bridge pier in the Lehigh River in Allentown, Pennsylvania. The bridge is located in an area underlain with dolomite rock, presenting karstic conditions including irregular top of rock and solution openings that provided high hydraulic conductivity below the top of rock. Also, the presence of a zone of weathered rock and pinnacle rock prevented the advancement of sheet piles when constructing the cofferdam. Thus, the difficulties of advancing the excavation to the desired spread footing level resulted in the design change to drilled shafts during construction. Since the project was Design-Build, the design could be changed by a collaborative process through the efforts of the Contractor, its geotechnical and structural engineers, and the State's (owner's) geotechnical and structural engineers and construction management staff."

Jan 1, 2016

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 Peter Yen

This session consists of five papers. Three involved research on the properties of grout materials, specifically ultrafine cements and polyurethane grouts. Two papers present the development of soil grouting technology and monitoring methods. Of great interest are the papers on ultrafine grout penetrability testing focusing on the pressure filtration effects encountered in permeation grouting applications (Ericksson, Stille and Mittag, Savidis). The comparison testing of hydrophilic and hydrophobic polyurethane grouts submitted by Vrignaud, Ballivy, Perret and Fernagu assessed the long-term performance of these materials for repairing saturated cracks in concrete, subject to thermal expansion and contraction. Two very practical papers present the development of soil grouting, where permeation, fracture, replacement, jetting and other grouting techniques are utilized. The papers by Lees with Chuaqui and Warner present experience with ultrafine and other commonly used grout materials. Methods to measure and monitor the injection process and verify production progress are discussed.

Feb 10, 2003

By M. Hesham El Naggar, Maged A. Abdlrahem

"Hollow bar micropiles have constructional advantages such as: fast and low-noise and low vibration installation process and small installation equipment, which allow access to tight places. In addition, they have efficient load transfer mechanism, which facilitates carrying considerable load in compression and tension. The common practice is to use diameter ratio of drill bit/ hollow bar (Db/Dh) around 2 in their construction, and they are typically designed assuming type B as classified by the Federal Highway Administration (FHWA). In this paper, the performance and capacity of Hollow bar micropile with different (Db/Dh) ratios are investigated. Full-scale micropiles were installed at a site in Ontario, Canada, and were tested in order to evaluate the uplift performance of Hollow bar micropile with different(Db/Dh) ratios. Two micropiles with two different ratios 2.25 and 3 were constructed and tested. The total length of the micropiles was 6m with embedded length of 5.75m. The soil at the site was primarily medium dense to dense sand. The results of the load tests are presented and discussed. It was found that the uplift capacity of the micropile increased by about 19.5% as Db/Dh increased from 2.25 to 3.INTRODUCTIONMicropile is a small diameter, less than 300 mm, drilled and grouted pile and is typically reinforced according to Federal Highway Administration (FHWA, 2005). The technology of micropile was introduced in North America in 1970’s, but the growth in the east coast of United State was intense compared to all other cities around the globe (Bruce and Nicholson, 1989). Nowadays, micropile construction is used extensively worldwide as a viable solution that offers several advantages such as fast installation in low headroom, minimal disturbance to the adjacent structure efficient load transfer due to high grout to ground bond strength. As the method of grouting has major influence on the grout – ground bond strength, FHWA has classified the micropiles into four categories. Type A: the grout is placed under gravity and no pressure is required. Type B: The grout is typically pressurized under a pressure range from 0.5 to 1 MPa as the temporary casing is withdrawn. Type C: the grout is placed in two-step process. First, the grout is poured under gravity only as in Type A. Before the hardening of the grout, similar grout is pressured of at least 1MPa without the use of packer. Type D: Like Type C, it is a two – step process, the grout is placed under gravity as in Type A and sometimes pressurized as in Type B. After hardening of the initial grout, additional grout is pressurized between 2 to 9 MPa through sleeved pipe by using packers, as many times as needed. According to this classification, hollow bar micropile is usually designated as Type B. However, the construction technique is completely different from Type B. Recently; there is a trend to supplement the four types of micropiles by Type E as represent to hollow bar micropile (Timothy et al, 2012). The construction method of hollow bar micropile involves two main stages which can be performed in one–step process: advancing the drilling bit attached to a threaded hollow bar to the required depth; and pressurizing the grout through nozzles of the drill bit."

Jan 1, 2016

By Nino Catalano, Meeok Kim, Gordon Chen

"The design of the below grade structure of Brigham Building for the Future (BBF) included three different areas to provide power generation and medical facilities as well as a parking garage. The three areas are divided and bounded by 3 foot thick slurry walls. Because each area has different depths and functions, the excavation and construction of the below grade structure presented considerable design challenges. The intricate sequence of excavation and construction between the areas was numerically simulated using a finite element analysis to assess the behavior of the slurry wall and the retained soil. The slurry wall and the related bracing system were modeled as a linear elastic beam and truss element respectively while the soil behavior was simulated using a hardening soil model. The interaction between slurry wall and soil was facilitated by the implementation of an interface element in the numerical model. The design of bracing system to adequately support the slurry walls during the excavation was done based on the envelope of the numerical responses in stage analysis. Predicted lateral displacements of slurry walls were later compared with the field measuring data. The comparison indicated a close agreement.INTRODUCTIONBrigham Building for the Future (BBF) is located in the Brigham and Women’s Longwood medical campus of Boston. The building will serve, once completed, as a biomedical research center and clinical facility to carry out a commitment by Brigham and Women’s Hospital to be the most technologically advanced facility in the country.The 11 story building will also feature a roof garden. The below grade portion of the building has a footprint of 265 feet wide and 210 feet long and is divided into three areas, a 6 stories garage, a cogeneration plant, and an imaging center. BBF was designed and constructed to achieve LEED Gold certification and will have high efficiency and improved sustainability as a medical facility. Ground breaking was in May, 2013. Below grade construction was completed in April, 2014 and the entire building will be finished in late 2016.As shown in Figure 1, the garage area has the largest foot print, 265 feet wide and 125 feet long. The lowest floor of the garage is located about 70 feet below grade. The co-generation plant is about 190 feet wide and 85 long and 50 feet deep. The imagining center is the smallest among three areas. It is 75 feet wide and 85 feet long and 22 feet deep. The areas are separated and bounded by 3 feet thick slurry walls.The perimeter and inner slurry walls were designed to support column loads from the above grade structures, lateral soil pressures and earthquake loads as per the building’s permanent condition and requirement. However the contractor was required to design the temporary bracing and the reinforcement for the slurry walls to resist construction stage loadings."

Jan 1, 2017

By Sina Z. Yekta, Zhangwei Ning, Pierre Frappin

This paper describes a DC (direct current) electrical resistivity method, which uses the contrasts in resistivity measurements to estimate the diameter of jet grouted columns as soon as they have been completed, with varying depth and water table, and without excavation. The measurement procedure is illustrated by several examples of application sites, including the Grand Paris tunneling works during the last 3 years where the method was systematically recommended in quality control for jet grouting works.

Sep 8, 2021

By H. Yoshida

Jet grouting was first introduced in Japan in the second half of the 1960s, approaching 50 years ago. By the end of the first 40 years, jet grouting from single to triple fluid systems had become a global technology. In the last ten years, progress in the jetting has been remarkable, and operational efficiency has improved. The quantity of carbon dioxide emitted in unit soil improvement has become one-third that of the initial technology. Meanwhile, technologies in waste recycling and horizontal jet grouting are also emerging. This paper discusses developments in the most recent ten years.

Jan 1, 2010

By Chu E. Ho, Alfredas Daugiala, Nicola Ebanks

"The construction of an ancillary structure for the new Second Avenue Subway Line in Manhattan, New York City involved a deep excavation in highly variable rock conditions adjacent to a fragile masonry building. The maximum difference between the lowest and highest rock elevations was about 30 feet, which posed a problem for the installation of secant piles that formed the supporting retaining wall for the excavation. At certain areas, the rock levels were higher than the top of the invert slab of the ancillary structure. To avoid disturbance to the adjacent fragile building, the secant piles were fully cased for drilling through the overburden soils and the rock sockets were formed using non-vibratory technique. This paper discusses the design and installation details of the secant pile wall and the contingency measures that were considered to mitigate the highly variable rock conditions. Monitoring of the adjacent fragile building showed that impact of pile installation were controlled within tolerable limits and safety of the building was not compromised.INTRODUCTIONThe 96th Street Station forms part of the newly constructed Second Avenue Subway Line on the East side of Manhattan Island, New York City (Figure 1). During construction of this station, several deep excavations were carried out adjacent to existing fragile buildings (Arksman et al. 2012, Grigson et al. 2016). These fragile buildings were typically four to five stories high, with a single rubble wall basement supported on timber piles or seated directly on the fill. The timber piles were often found to be in a poor condition and connections to the footings were compromised due to rotting of the timber within the zone of water table fluctuation. Several of these fragile buildings had to be strengthened and underpinned to improve the stability of the structures prior to commencement of excavation for the new subway station box (Trabold et al. 2012, Ho and Pena-Iguaran, 2013). The situation was most challenging at Ancillary Buildings 1 and 2 located at 93rd and 97th Street respectively, where secant pile walls were located merely 2 feet away from the adjacent property line, due to architectural space constraints. While mitigation of excavation induced ground movements can be controlled by the adoption of a stiff excavation support system, a more concerning factor was the uncertainty associated with the impact of the secant pile wall installation on the stability of the existing fragile buildings. This was particularly difficult at Ancillary 1 where the secant piles encountered highly variable rock levels that intruded into the excavation space. The following sections discuss the design and installation of the secant pile wall and contingency measures that were considered at Ancillary 1."

Jan 1, 2016