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By Hayel M. El-Naggar, Mohamed Sobhi, Mamdouh M. Hamza, Marawan M. Shahien

"This paper presents the results of two lateral load tests on large bored piles in soft clay deposit for a major site in northern Egypt. The tests are carried out on 0.8 m diameter piles. One of the tests is carried out on the pile where the clay starts from the ground surface. The other test is carried out on a pile after surface improvement by replacing the top 1.50 m of the clay deposit by compacted granular soil. The results of the tests show the influence of the surface replacement layer on the lateral load versus lateral displacement relationships of the loaded pile. The results of the two tests are used to calibrate a 3D Finite Element Analysis model for the pile. The model is used to investigate the influence of the thickness and lateral extent of the surface replacement layer on the behavior of laterally loaded large bored piles.INTRODUCTIONLateral loads for piles are produced by seismic events, wind, wave action, ship impact, traffic, and land slide forces. The lateral resistance of a pile is controlled by the stiffness and the strength of the material of the pile and the soil surrounding the upper portion of the pile. In most situations, the soil surrounding the upper portion of the pile is too weak to sustain the design lateral loads. Thus there is a need to increase the lateral resistance of the pile or groups of piles. Such an increase may be achieved by either increase number of piles or increase pile diameter. Alternatively, an economic way to increase the lateral resistance is to improve the soil surrounding the upper portion of the pile (Rollins and Brown, 2011; Faro et al., 2015).Ground improvement has the ability to increase the lateral resistance of the pile by increasing the passive resistance of the soil surrounding the upper portion of the pile. The ground improvement techniques have the potential for being more cost-effective and reducing construction time. In spite of this fact, such techniques are rarely implemented in practice. Further, there are relatively few tests or records available in the literature to guide engineers in evaluating the actual effectiveness of this approach. In addition, there is no standard or methodology to aid engineers in designing increase of lateral resistance with surface ground improvement. There are specific improvement methods for each soil type, whether it is loose cohesionless soil or soft cohesive soil and these methods are provided by Michell (1981), Tershai and Juran (2000), ASCE (1997), and Rollins and Brown (2011). Furthermore, there are number of case histories that add a new hole in the sight, such as the cases provided by Brown et al. (1987, 1988), Mokwa and Duncan (2001), Rollins et al. (2005), Rollins and Cole (2006), Cole and Rollins (2006), Rollins, Snyder et al. (2010) , Rollins, Gerber, and Kwon (2010), Rollins and Nasr (2010), and Gerber et al. (2010)."

Jan 1, 2016

By Mark Koelling

This paper presents a case history of a ground improvement program conducted in a soft soil environment and seismically active region in the northwest corner of Washington State near the Canadian border. The program was performed over several years, and provided adequate soil bearing conditions for the construction of several structures. Completed development includes separate construction of four adjacent structures, each with unique total and differential settlement requirements and built at approximate two year intervals. Site soils consist of 45 feet of loose saturated sand and silt overlying 70 feet of very soft to stiff (N60 = 0 to 7) normally consolidated clay. Adding to the complexity of the site is the owner?s requirement that all existing structures remain open and in service during construction of each subsequent structure. The paper presents the site geotechnical information and the foundation design issues. Details of a combination of ground improvement methods is presented, including stone columns, wick drains, a preload surcharge, and staged construction to provide soil support for shallow foundation construction of all structures at this site. The soil test results and settlement observations are presented along with QA/QC measures. Lastly, a brief method sustainability comment will be made.

Jan 1, 2010

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

By Swaminathan Srinivasan, Aaron J. Muck

"When an opportunity arises to combine state-of-the-art concepts with advanced modeling tools, engineers need to take what they know and apply forward thinking to geotechnical solutions to promote the state-ofpractice. Such an opportunity was seized during the design and construction of the Great American Tower in Cincinnati, Ohio. The forty-one story Great American Tower at Queen City Square – currently the tallest building in Cincinnati – has not only changed the downtown skyline, it is also contributing to the advancement of the state-of-the-art use of auger cast-in-place (ACIP) piles as settlement reducers. Predicted settlements of a traditional mat foundation were excessive, and the costs and construction time associated with traditional ACIP piles extending to bedrock were not preferred. A mat supported on a limited number of ACIP piles, with the piles primarily acting as settlement reducers, was evaluated as the preferred foundation type.Promoting the unique soil-structure interaction of the foundation system with confidence required the use of sophisticated numerical modeling tools. Traditional standard penetration test boring data (SPT) was initially used to develop a numerical analysis of the soil-structure interaction using FLAC 3D software. The model was further modified with cone penetration (CPT) and pressuremeter testing (PMT), along with actual load test results on several ACIP pile elements of varying lengths, but all tipping above bedrock. Through a combined design team effort, and detailed numerical modeling analysis, ACIP piles were recommended for reducing mat foundation settlement. Instrumentation during and post-construction confirmed design assumptions and predictions. Integrating sound geotechnical concepts, and using advanced geotechnical analysis and design methods, traditional mat and ACIP pile foundations were successfully integrated into a unique foundation support system.INTRODUCTIONThe Great American Tower at Queen City Square in Cincinnati, Ohio is located within a region dissected by historical geologic deviances associated with the meander of the Ohio River and glacial progression/recession. Combining a challenging geology, with the development of a high-rise office building afforded the design team an opportunity to combine state-of-the-art soil-structure interaction concepts and method with traditional geotechnical engineering concepts. Such a combination required a variety of field tests, collaboration with the design team and owner, and geotechnical-structural modeling during the design phase. During construction, in addition to materials testing and observation, a variety of instrumentation systems were employed. Together, the data was used to corroborate the design model and make adjustments during construction and further substantiate design assumptions following construction."

Jan 1, 2015

By Abdelmalek Bouazza, Aamir Mahawish, Will P. Gates

Bio-grouting by means of microbial induced calcite (calcium carbonate) precipitation (MICP) to improve mechanical properties of granular soils has gained much attention in recent years. The biogrouting process offers an alternative and environmentally friendly approach to conventional soil improvement techniques, such as cement. Bio-grouting by urea hydrolysis has been extensively applied to tackle various geotechnical problems. However, it has yet to be applied to improve engineering properties (compressive strength) of a coarse cohesionless material with the aim using it as sand/stone columns within soft and very soft soils. This paper investigates the effect of using light, moderate and heavy biochemical treatments on the unconfined compressive strength (UCS) of coarse sand columns. In addition, the microstructure of the bio-cemented coarse material has been analysed by X-ray computed tomography (XRCT). The experimental results revealed that the UCS could reach up to 200kPa, 1000kPa and 5500kPa for light, moderate and heavy bio-cemented coarse sand columns, respectively. The microstructure investigations showed that the deposited calcium carbonate can be identified using XRCT imaging and can be associated with the gain in UCS values. Various microstructure properties, such as void ratio, dry density and porosity were also identified and compared with the laboratory data.

Jan 1, 1900

By Chris Harnan, Christophe Justino

The European Federation of Foundation Contractors (EFFC) and the Deep Foundations Institute (DFI) jointly published Edition 1 of the ‘EFFC/DFI Guide to Support Fluids for Deep Foundations’ in April 2019. This Guide was prepared by a Task Group comprising experts on deep foundations from contractors, materials suppliers, consultants and academics. The Guide builds on work carried out by the Tremie Concrete Guide Task Group and presented in Edition 2 of the Tremie Guide. The Paper discusses and describes the content of the Support Fluids Guide which presents the state of the art on support fluid management, as well as the R&D work currently being carried out and funded by EFFC and DFI sponsors through an ongoing Field Research Study (FRS) as well as a review of academic research linked to the EFFC/DFI joint effort aimed at improving knowledge and guidance on support fluids. The FRS and academic research will help to improve the understanding of relevant support fluid properties including stability of excavations, interface layer formation, effect of filter cake and the development of new sampling and testing methodology. The Paper also presents the initial findings from the FRS program as well as a discussion on the challenging aspects of support fluid management with emphasis on design, performance, testing, and the environment.

May 1, 2022

By Glen Mann, H. G. Vestberg, Robert D. Holtz

"Underpinning of residential and commercial structures is often accomplished using a number of driven-in-place small diameter steel pipe piles. These piles, at least in the Seattle area, are typically described as pin-piles and are driven with an air compressor operated jack hammer to a refusal criterion developed from an empirical basis. Over the past twenty years or so, the materials have improved in quality and strength, and the driving equipment has improved in efficiency and capability. These improvements have resulted in damage to the pin-piles during driving as well as to the driving equipment. The primary objectives of this load testing study were to develop a relationship between the driving penetration resistance of 2-inch diameter pin-piles and the ultimate bearing capacity when piles were driven at different penetration rates and, based on the load test results, to develop an opinion regarding an increase in the allowable axial load capacity [ultimate load capacity divided by a factor of safety] of a 2-inch diameter pin-pile over the currently used permissible load capacity of 4 kips in the Seattle area. Also, if feasible, a reduction in the present driving penetration rate was to be recommended to help reduce the rate and magnitude of pile and equipment damage whilst maintaining the allowable load capacity. The recorded ultimate bearing capacities were also compared with the Tagnent-line and the Davisson analytical methods in an effort to determine if either of these provided a reasonable determination of the pile load capacity.IntroductionThis paper describes the results of a series of load tests performed on small diameter, 2-inch, driven-in-place steel pin (pipe) piles and based on these results, provides the support for a modification to the presently used allowable axial pin-pile capacities.The intent of the load testing program was to determine how much influence the penetration resistance might have on the individual piles' ability to support the allowable axial load without undergoing any significant vertical deformation. For the purposes of this paper the ""allowable load capacity"" is considered to be the ultimate pile load capacity divided by a minimum factor of safety, typically considered to be 2.0 in this area. A pin (pipe) pile comprises an open or closed ended, schedule 80 steel tube which is driven-in-place, usually with an air compressor operated 90 pound pneumatic jack hammer. These jack hammers typically operate at a rate of about 1,200 blows per minute, (Haggard, Holtz and Mann, 2001 )."

Jan 1, 2005

By Jack Taggart, Chris Barker

Pile load testing strategies for large infrastructure projects and multi-phase building developments have historically justified cost and programme benefits for undertaking advance preliminary and working pile load testing. However, more recently piling and pile load testing strategies have included assessment of the embodied carbon to understand and present the carbon savings that can also be achieved. This paper gives an overview of the factors contributing to carbon and emissions in the construction of bored pile foundations and presents the methodology taken in assessing embodied carbon as part of the pile load testing strategy for a multi-phased building development in London. Potential embodied carbon savings for various bored pile types and load testing strategies are discussed alongside alternatives and other considerations including pile re-use and carbon offsetting to inform continual improvement for future projects.

May 1, 2022

By Kessi E. Zicko, Eric A. Hackenberg, Paul J. Lewis

"Following snow melt and spring rains in 2011, a landslide measuring approximately 600 feet long and 300 feet in slope length occurred within the southbound roadway embankment of a heavily travelled 2-lane divided highway in North Central Pennsylvania. Driven steel piles were designed to stabilize the embankment slope. Factors affecting the selected stabilization technique included an adjacent reservoir, wetlands, the length and depth of the failure plane, extent of glacial lake deposits, excess pore pressures in the foundation soils, and an area of archaeological interest. Field reconnaissance and subsurface explorations including borings, instrumentation, geophysics, and laboratory testing indicated that glacial lake deposits were present in the toe region of the embankment. Instrumentation proved key in measuring excess pore pressures and in locating the failure plane, and geophysics was utilized to estimate the extent of the soft glacial lake deposits and to estimate pile lengths. The existing condition of the embankment was modeled in computer slope stability analyses, which were also used to help assign soil parameters. Significant costs were associated with constructing a berm due to the impacts on adjacent site features. Therefore, multiple rows of driven steel H-piles were designed for installation along the toe of the embankment. The design lateral load in the piles was based on slope stability analyses, and the pile size and number of piles were based on lateral pile computations with modified p-y curves to account for installing piles in an active landslide. The relationship between the factors of safety from slope stability and the LRFD pile design was significant in determining pile loads for lateral analyses.INTRODUCTIONA landslide developed along the lower portion of the southbound embankment of State Route 15 in Tioga County, Pennsylvania. The road passes through a steep valley and is located along the southern extent of the Tioga Reservoir. Although no damage to S.R. 15 was attributed to this landslide, the close proximity of the slide to the road posed a concern for the long-term stability of this section of roadway.This paper presents a summary of the site history; the subsurface conditions based on borings, instrumentation, a geophysical survey, and laboratory testing; slope stability analyses including alternatives assessment; and the pile design.SITE HISTORYS.R. 15 was originally located in the valley along the Tioga River and traversed through the towns of Tioga and Mansfield. Although the reason is unknown, it is interesting to note that Old S.R. 15 curved away from the river in the area of the landslide. In the mid 1970’s, S.R. 15 was relocated to the eastern hillside prior to construction of the Tioga-Hammond Reservoir by the U.S. Army Corps of Engineers. The relocated highway was constructed in stages. Two lanes of relocated S.R. 15 were initially constructed to carry one lane of northbound and one lane of southbound traffic. At this same time, the majority of the fill was placed for two future lanes immediately to the west, which would eventually allow for two lanes in each direction. The two eastern lanes would then carry northbound traffic after completion of the two southbound lanes to the west."

Jan 1, 2015

By Danny Winters, Wesley Schmutzler, Christopher Lewis, Matteo Bertoni

"SR 83/US 331 is a primary North/South roadway in Walton County that is a crucial link for tourism and commerce between the Walton County beaches and the heavily traveled I-10 corridor in the panhandle of Florida. The facility also serves as the primary hurricane evacuation route from southern Walton County. This 3.4 mile project involves expanding the current two-lane crossing of Choctawhatchee Bay to a fourlane facility to increase capacity and dramatically improve mobility within the corridor. One of the major goals of the project is to perform ground stabilization using Deep and Shallow Soil Mixing (DMM & SMM) along existing causeways. Ground stabilization is required due to the existence of moderately deep very loose soils that have settled considerably over the years. As a result, the Florida Department of Transportation (FDOT) incurred significant maintenance expenses and was unable to maintain an acceptable ride quality. FDOT considered soil mixing as one option to control this settlement. Quality Control for soil mixing relies heavily on the monitoring system used to control mixing parameters. This paper will examine in detail, the reporting of the Drilling Mate System (DMS) used to ensure the quality of each soil mixed element.INTRODUCTIONThe Florida Department of Transportation (FDOT) issued a Design-Build Maximum Price Request for Proposal (RFP) for the Choctawhatchee Bay Bridge expansion. The design-build (D/B) team of Skanska/Parsons Brinckerhoff was awarded the contract. The D/B team, in order to meet the unique deep ground improvement challenges of the Choctawhatchee Bay Bridge Project, selected Foundation & Geotechnical Engineering (FGE) as the engineer to design the ground improvement and TREVIICOS South (TIS) to execute the works.The FDOT in their RFP states that “either bridge or utilize a deep ground improvement method to stabilize the three segments of the existing earthen causeway” and “one possible method of deep ground improvement which is considered viable is deep soil mixing”. FGE developed a proposal to provide a unique rigid transfer platform to effectively stabilize the existing causeways. This platform (Fig. 1) consists of an upper 10 ft thick stabilized soil layer which transfers axial load to a series of deep columns. This robust system guarantees superior durability, ride quality and pavement condition and will exceed all required design and performance criteria including, “Less than 2 inches of settlement within a 1,000-foot section”."

Jan 1, 2017

By Jason Herron, Joseph Brown

The common couplings for joining sections of helical piles with an outside diameter of 6.625 inches and 8.625 inches are square on square, flange to flange, external pipe sleeve, internal pipe sleeve, and welded joint. Each coupling type has advantages and disadvantages in efficiency, capacity, installation, and economics of the installed pile. All these coupling types have been used in the helical pile market in North America for various applications and designs. Many of these applications require on-site testing, but test records are not typically shared with the helical pile industry. Due to the lack of information available for square on square and flange to flange couplings, testing was done to compare the efficiency of installation, load to deflection response, and torque to capacity ratios of external pipe sleeve, square on square, and flange to flange couplings. Field installations and tension tests were performed in non-cohesive (sand type) soil near Caseyville, IL and in cohesive (clay type) soil in Centralia, MO. The data collected during these tests included rotations per foot during installation, installation torque, applied pressure, and deflection. The results of this testing are analyzed and discussed within this paper. The results indicate that the square to square coupling is the most efficient of the designs tested, but this conclusion cannot be fully justified without further testing due to the variability in the data gathered and the small number of piles tested. INTRODUCTION A helical pile is typically assumed to be a medium-displacement pile when its outside diameter is between 4.5 inches and 8 inches and a high-displacement pile when its outside diameter is greater than 8 inches. A helical pile designer has multiple options when selecting a coupling type for medium- to high-displacement helical piles. Each type of coupling has advantages and disadvantages and must be analyzed on the bases of efficiency, capacity, installation, and economics of a project. Typical couplings that are chosen by designers include square on square, flange to flange, external pipe sleeve, internal pipe sleeve, and welded joint. A helical pile must transfer axial, lateral, bending moment, and torsional loads, and the coupling must be designed to effectively and efficiently transfer each type of load. During the installation of a helical pile, the rate of penetration and the disturbance of soil layers play a critical role in the efficiency and torque to capacity ratio (Kt) of the pile. It is common for a coupling to protrude beyond the outside diameter of the pipe section being used. This is necessary for the function of certain coupling types and can facilitate the connection of couplings. However, it causes increased soil disturbance and reduce the rate of penetration due to soil bearing against the protruding portion of the coupling. A helical pile designer typically will work to minimize the coupling protrusion and create a pile with optimal installation efficiency but may choose a design with lower installation efficiency if it offers sufficient economic advantage.

Jan 1, 2019

By Murad Y. Abu-Farsakh, Md Habibur Rahman

The properties of all natural soil deposits are highly variable, and they are rarely homogeneous. Cone penetration tests (CPT) were used to assess the site variability, which was then incorporated into the Load and Resistance Factor Design (LRFD) of pile foundations. Data from six project sites with multiple CPT tests conducted at various locations were collected for this research. The semi-variogram was used to assess the spatial variability of CPT data (corrected tip resistance, qt) for each location. For each location, the coefficient of variation due to spatial variability (COVR,spatial) was calculated. From COVR,spatial and COVR,method, the total coefficient of variation (COVR,total) for each site was calculated, which was then used to calibrate the resistance factors (ϕspatial, ϕtotal) for use in LRFD pile foundation design. The findings of this study demonstrated the importance of using site variability in LRFD pile design. For sites with lower site variability than the design method (i.e., COVR, spatial < COVR, method), the value of the COVR, total will be decreased, and hence the resistance factors (ϕspatial or ϕtotal) will be increased (credit), and vice versa.

Sep 8, 2021

By Gary L. Seider, Dana A. Wesolek, Fred C. Schmednecht

"A new condominium project, The Atelier, developed by Pickus Companies located at the corner of Bryn Mawr and Sheridan in Chicago, IL required an earth retention system to protect the surrounding roads, alley, and existing neighboring apartment bui lding during its construction. Slurry Systems, Inc. (SSI) and Ground Engineering Consultants, Inc. designed the earth retention system using cantilevered sheet piling for three of the four sides: two sides bordering major streets and one side bordering an alley. For the fourth side, which borders an existing occupied brick building, a combination of sheet pil ing and AB. CHANCE® helical screw piers were used. SSI was actively involved in the review process of its earth retention system with the City of Chicago and quickly learned that there was no specific code for hel ical piers/anchors. (It appears that this is the case with most metropolitan cities throughout the United States). Consequently, the approval of underpinning for this project became the critical path, as much testing, calculations, meetings, and other details were required prior to its approval.SSI and AB. CHANCE® recognized that this process for underpinning approval must be seen by other contractors/suppliers who wish to use helical piers/anchors in the City of Chicago. Consequently, this project served as an opportunity to work with the City of Chicago and the City's Building Code Committee in furthering the development of the Helical Piers/Anchors Code, Section 1814. INTRODUCTION - HELICAL PIERSDefinition. A helical pier or anchor consists of one or more helix-shaped steel bearing plate(s) attached to a central steel stem (solid bar or pipe), which is installed by rotating or ""torquing"" into the ground. Each helix is attached near the tip, is circular in plan , and is formed into a screw thread with a defined pitch. Helical piers/anchors are pre-fabricated and can derive their load-carrying capacity through both end bearing and skin friction. The helical piers/anchors can be augmented with grout."

Jan 1, 2005

By Mary Ellen Bruce

Let me first address the issue of the wet grab samples. The wet grab samples that were attempted to take on the Central Artery were hindered by the fact that the way the mixing was being done was only by injecting grout on the way out, during withdrawal of the mixing tools. They would auger down to the required depth (usually with some water being injected), which took anywhere from 45 minutes to an hour, and then when coming out, the grout would be injected with grout. That was leaving a column of grout in the center where the shaft had been (i.e. inside of the blades of the mixing tools), which would end up being something like a foot in diameter because the pipe that was used for the drill shaft was a foot in diameter. So we had 10 inches to a foot of almost pure grout in the middle of our column and then we had 2 feet on either side that was mixed soil cement. So when they went down with the wet grab sampler not knowing where that was in the column sometimes they/we were getting strengths of 1500 psi, and sometimes they/we were getting strength of 500 psi or 100 psi. So what was it that we were taking into the wet grab sampler? In those cases you don&apos;t really know, but it wasn&apos;t representative of the core samples we were taking. We were purposely not coring in the center because we knew that was going to be high cement content, almost pure grout. So the issue of wet grab sampling particularly on this project, the Central Artery Project, was that we didn&apos;t really know what we were sampling. What becomes an issue with wet grab sampling in other projects is that you have to have another device (machine) in most cases, a cherry picker crane or something similar that can raise and lower with a beam that is used to forces the sampler down into the freshly mixed soil-cement. And regarding economics, is it more economical to have that crane standing by with its operator or to have a drill rig to come along later and do the coring and take the material out that&apos;s fairly identical to what you&apos;re finding in situ? The complaint of micro-fracturing in the core samples as you&apos;re taking the cores was raised by Seiko as causing large strength reductions. But, if you&apos;re doing it carefully, then I don&apos;t think that&apos;s much of an issue anymore, on research basis perhaps but not on a practical level.

Feb 10, 2003

By Mark Zablocki, Dakarai McCoy

Ground vibrations are an unavoidable effect of driving piles and may pose a risk to nearby infrastructure and the comfort of adjacent occupants. Driven-pile-induced ground vibrations are known to vary widely based on ground conditions, pile material, and installation means and methods. A monitoring sensor to record ground vibrations during pile driving is necessary for understanding potential impacts to sensitive infrastructure and should be considered when implementing a monitoring program anticipating ground vibrations. The implementation of a vibration monitoring program historically relies on experiential-based decision-making, which may result in the costly vibration monitoring of low-risk infrastructure. Prior understanding of anticipated ground vibrations is necessary to create an appropriate monitoring program. A framework is proposed for organizing data from past monitoring programs and quantifying the anticipated risk of driven-pile-induced vibrations. An example of risk quantification from data imported to ]a cloud database is presented by comparing driven steel H-pile and prestressed precast concrete vibration monitoring measured and collected by Haley & Aldrich between 2010 and 2020. The methods presented within the example can be applied to quantify a first order approximation of risk for ground vibrations at proposed driven pile sites based on the measured performance of previous sites with similar ground characteristics and pile installation methods. The presented novel data managements tools allow for a quick aggregation of vibration data with similar site conditions.

Sep 8, 2021

By Christopher Sammon, Nicholas Turus

"The demand for underground parking in South Florida has increased as a result of changes to the local building code, coupled with developers’ desire to improve building aesthetics and provide much needed walk in retail space for high-end structures. Historically, underground construction was uncommon in South Florida due to the high groundwater level and porous soil/rock. Conventional dewatering methods become ineffective only a short depth below the ground surface and deeper excavations have required a tremie seal solution consisting of wet excavation and the pouring a temporary unreinforced slab under a water head. However, as excavation area and depth increase, the cost and schedule of the tremie seal method become problematic. For these reasons developers and construction teams alike have looked to contractors in South Florida for alternative means of construction.This paper details the construction of two sites in South Florida where Deep Soil Mixing (DSM) technology offered an efficient alternative to tremie seal construction. The Brickell City Centre required excavation of 8 acres to depths of 30 feet, and augercast piles up to 36” diameter and 110 feet in depth. The second site, Jade Signature, required an excavation of up to 41 feet directly adjacent to the Atlantic beachfront. Due to the concerns over differential settlement, the project featured a soil mixed gravity wall that was designed and installed to allow for completion of the tower prior to excavating the adjacent garage.Both projects involved improving every square inch of ground beneath the planned project excavation. The developed DSM seal slab solution creates a nearly impervious excavation at excavation invert with the strength to resist hydrostatic uplift forces. Low permeability site perimeter walls are constructed to complete the sealed excavation and reinforced with either beams or sheet piles for structural support. Augercast piles required for the permanent hydrostatic concrete slab supplement the uplift capacity of the DSM. After DSM and augercast piles are installed from grade, the site is excavated in dry conditions."

Jan 1, 2017

By Alex Ryberg, Matthew L. Becker

Several integrity testing methods exist which may be used to evaluate drilled shafts. Each test method has advantages and limitations. On occasion, the results from different test methods may lead to conflicting conclusions, making it difficult to conclusively know which results more accurately represent the quality and integrity of a drilled shaft. This case study focuses on the integrity testing evaluation for two drilled shafts which were constructed using permanent casings and installed through flowing river water. Integrity testing was performed using Thermal Integrity Profiling (TIP) and Crosshole Sonic Logging (CSL) on each shaft. During testing, the influence of flowing water and soil layering needed consideration in the collected TIP data. Similarly, concrete curing time influenced the CSL test results and required the CSL tests to be performed multiple times with additional wait times following concrete placement. To aid in the shaft integrity evaluations, Low Strain Integrity testing via the Pulse Echo Method (PEM) was performed on several shafts and concrete coring was also performed to help further assess the acceptance or rejection of the questionable shafts. This paper presents an overview of the testing methods that were applied, their basic methodology, as well as potential limitations that should be considered when evaluating their results.

Sep 8, 2021

By David Chadwick, Paul Marsden, Chris Hughes, Mathias Delapille

"Following damage caused by the 2011 Christchurch earthquakes, the NZ$127.5million Christchurch Town Hall Restoration project is due for completion in 2018. The building is undergoing extensive repairs and a strengthening regime to meet New Zealand’s New Building Standard. One major aspect of the project is the stabilisation of the soil directly beneath the building using interconnected jetgrouting columns installed a cellular configuration, the purpose of this being to decrease the likelihood and severity of foundation movements caused by earthquake-induced soil liquefaction and lateral spreading. The soils encountered on the site ranged from cobbles and gravels through to sandy silts with a significant quantity of timber and rootlets. This wide variation of soil types presented a number of challenges with regard to effective and consistent treatment by jet grouting. The paper presents an overview of the quality assurance practices and also the testing regime adopted on this project.INTRODUCTIONMost of the deformation experienced by the Christchurch Town Hall structure over the course of the Canterbury earthquakes was caused by movement of the underlying ground. Two primary mechanisms of ground deformation were observed:- Liquefaction of the soils underlying the building foundation- Lateral spread of surface soils towards the free face at the river edge which runs 20 metres from the building. This mechanism also resulted in additional vertical settlement of the building foundations.The overall foundation design philosophy adopted by the project team for the Christchurch Town Hall Conservation Project has been to improve the ground directly beneath the structure to mitigate against these two mechanisms of ground movement. Additionally, a robust raft slab is proposed to distribute the foundation loading more evenly and increase the ability of the structure to resist lateral stretch of the underlying ground.The ground improvement system proposed by the Client’s geotechnical consultants, Tonkin &Taylor, comprised a cellular arrangement of interlocking jet grout columns, this arrangement would effectively encapsulate the soil within the cells preventing lateral spread.In total 1,097 interlocking jet grout columns, extending over the entire floor plan of the structure, were required to satisfy the design requirements."

Jan 1, 1900

By Carlandrea Albonico, Salvatore Miranda

After a brief introduction of the whole Project, the paper describes two special geotechnical engineering solutions provided within the scope of the Galataport Project, in Istanbul, Turkey. The first refers to the new quay of Salıpazarı, which is a combination of retaining structure and ground improvement, formed by a combiwall, a reinforced concrete diaphragm wall and a soil improvement by deep soil mixing (Turbojet). The second, refers to the soil improvement works executed underneath three existing buildings. Single-fluid jet grouting columns had the scope of improving the mechanical properties of the bearing soil and reducing the associated risk of liquefaction. A set of underpinning micropiles was installed in order to allow the excavation of a partial basement inside two of these three buildings. All activities were conducted from inside the existing buildings, with reduced headroom. The paper highlights the importance of employing cutting-edge technologies within the foundation engineering field and state-of-the-art electronic control devices, in parallel with the essential human expertise, in order to obtain the desired results in this high-profile Project.

Nov 1, 2022

By Tony P. Suckling

This paper describes an investigation into the bleeding behaviour of bentonite slurry observed on a trial diaphragm wall panel. The bleeding is thought to be due to the bentonite experiencing a chemical reaction leading to settlement of the solids within the fluid, possibly as a self-weight consolidation process. The trial panel was constructed in a busy airport environment where many different chemical products are used for de-icing the aeroplanes, runways, apron areas, vehicle access and pedestrian routes. The relationships between slurry contamination, bleeding, bentonite hydration time and filter loss behaviour were examined as no relevant published literature could be found. The results show that the amount of bleed strongly depends on both the degree of contamination and the hydration time. It is concluded that bentonite fluids should be allowed to sit in the storage tank for at least 24 hours after mixing, and that the filter loss test is a quick and effective method to determine the potential for bleeding of contaminated slurries.

Jan 1, 2011