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By Mark Maday

As part of the I-94 North-South Corridor reconstruction program, the Wisconsin Department of Transportation (department) is reconstructing the Mitchell Interchange in Milwaukee, Wisconsin. Located on the south side of Milwaukee near Mitchell International Airport, The Mitchell Interchange interconnects I-94, I-43 and I-894. Reconstruction began in 2009 with the letting of the first advance contract for local crossroad bridge reconstruction. A second advance contract for construction of collector-distributer roads on each side of the I-94 mainline was completed in 2010. The main contract involving reconstruction of the core of the Mitchell Interchange was let in the summer of 2010, and is scheduled to be completed by the end of 2012. The core contract includes construction of three cut and cover tunnels along two system interchange ramps. Construction of the three tunnel structures is on the critical construction path. The contract includes an interim contract completion date that requires the tunnels to be open to traffic by the end of 2011. A top down method of construction using drilled shaft secant piles for the sidewalls of the cut and cover tunnel structures was selected as the preferred structure type to address subsurface and construction schedule challenges. The department identified in pre bid coordination that no cost reduction incentives would be reviewed or accepted for changes in tunnel wall type. A major component of the tunnel structures requires the installation of 1,500, 4-foot diameter secant piles. This paper presents mitigation strategies to manage construction risks associated with the installation of the secant piles including; prequalification of the secant pile subcontractors, requirement for use of full depth temporary casing, a site specific quality control plan, specifying drilling equipment, and developing a geotechnical baseline report for this critical component of the Mitchell Interchange reconstruction project.

Jan 1, 2011

By Walter E. Vanderpool

Full scale load tests are frequently performed immediately prior to deep foundation construction to verify the design assumptions. Occasionally, load tests are performed during design development and applied to the final design for critical and non-redundant structures. We believe that full scale load tests can be very valuable and economical for projects, especially in a geologic environment where the record of full scale load testing is very limited or non-existent. The load testing for the Utah Transit Authority?s Airport Light Rail Trax project provides an example of the advantages of a load test in design development. The savings realized by the owner was in excess of $800 thousand dollars.

Jan 1, 2011

By Claudio Asioli

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

Jan 1, 2017

By Claudio Asioli

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

Jan 1, 2017

By D. Cantali

This paper will be presented in two parts. The first part will present the latest advancements in pile installation techniques using state-of-the-art press-in piling technology by Giken. By pressing in sheet piles and large modulus contiguous steel tube pile walls – as opposed to the more traditional installation methods using percussive hammers or vibrators – retaining structures can be constructed effectively noise and vibration free. For over water and coastal projects with limited access, this provides significant environmental benefits in the form of minimising the construction foot print and the impact to surrounding communities and the marine natural habitat. Typical noise and vibration data will also be presented. The second part of this paper will review the current manufacturing techniques for sheet piles and introduce innovative new materials used in the current piling market for embedded sheet pile walls. Materials include long service life non – ferrous materials such as new age plastics and fibre reinforced polymer piles. Their excellent long term performance and durability make them an effective solution in the marine environment. For steel piles, a number of steel grades with reduced corrosion characteristics will also be discussed including a newly developed steel to combat corrossion in the low water zone, an area often exhibiting the highest moments in a retaining wall. A number of project case studies will also be presented to reinforce their relevance in today’s changing construction landscape.

Nov 1, 2022

By Prakash Annamalai Rangasamy, Muthukkumaran Kasinathan

"Infrastructure development like elevated expressways, metro train and flyover are required proper foundation system to carry heavy traffic loads/significant lateral load, especially in the presence of hard stratum at shallow depth. Pile foundation under bridge pier system is widely adopted in metro projects where the piles are essentially socketed in rock. However, the drilling in hard rock is a time consuming process and needs heavy machineries which lead to delay in construction activities. In the present study, the influence of free standing height on rock socketing under lateral load is investigated. The experiments were conducted on an instrumented model pile with varying depth of socketing and for varying Lf/D ratios. The experimental results shows the load carrying capacity of the pile increases by increase in Lf/D ratio, where in the case pile without socketing (bearing on rock) is compared with 3D depth of socketing. Thus socketing the pile provides significant benefits on carrying capacity of lateral loads. Embedding the pile into hard strata reduces the lateral displacements substantially compared with pile bearing over hard strata. Form the study, it is noticed that the influence of rock socketing has significant effect in the lateral load capacity. And also, the effect of free sanding height play a major role in the lateral load capacity of the rock socketed piles.1. INTRODUCTIONA substructure carrying heavy lateral load at shallow depth, the structure has to be socketed into hard strata to enhance the efficiency of load carrying capacity. The existing field practice is to socket the end bearing piles in hard strata over a minimum depth of four times the diameter of the pile based on rock classification (IS 14593:1998). Reese (1997) developed p-y curves for analysing drilled shafts in rock under lateral loading, based on strong and weak rock criteria. The proposed p-y curve approach has the ability to simulate the nonlinearity and non-homogeneity of the rock mass surrounding the drilled shaft. Gabr et al. (2002) proposed a hyperbolic p-y criterion based on field tests on small diameter drilled socketed shafts. By considering pile as linearly elastic semi-infinite space and soil as homogeneous isotropic material, Poulos (1971) proposed solution to determine the horizontal displacement and pile head rotation. Poulos (1972) extended this elastic continuum approach to give an approximate solution by considering drilled shaft and pile bearing on rock as fixed and pinned end boundary condition. Zhang et al. (2000) developed a non-linear continuum approach for drilled shafts in a soil and rock mass by considering the effect of soil and/or rock mass yielding on the behaviour of shafts. Randolph (1981) conducted a parametric study on the response of laterally loaded piles embedded in an elastic soil continuum. The study was conducted using the finite element method and the results were fitted with closed-form expressions from which the lateral responses of piles were calculated. The solutions given by Randolph (1981) were expanded by Carter and Kulhawy (1992) from the results of finite element studies on the behaviour of laterally loaded flexible and rigid drilled shafts in rock. Desai and Christian (1977) gave a finite difference program to solve rock socketed problems by considering soil and rock mass as elastic-perfectly plastic. Zhang et al. (2000) verified the proposed finite difference method with existing field test results. Gabr et al. (2002) and Liang and Yang (2006) proposed hyperbolic p-y curves based on filed test results and verified with finite element programs. However the need of field and lab scale experimental studies to validate the existing methods of analysis is necessary."

Jan 1, 2015

By Leonhard Weixler, Jean Wehbe, Gordian Ulrich, Franz-Werner Gerressen

"As alternative energy industries pick up speed internationally, and as government regulation and restriction limit the use of impact hammers due to environmental limitation from construction induced noise during pile driving operations, unconventional solutions for more complex offshore foundation installations have become a necessity. Manufacturers and equipment suppliers race to develop alternative techniques to accommodate for offshore foundation construction in various soil conditions and at greater water depth. The FLYDRILL, and the Seabed-Drill BSD are two innovative systems for the installation of offshore monopiles with reduced environmental impact.INTRODUCTIONThe FLYDRILL and the Seabed-Drill were born from techniques in the design and construction experiences gained from land based foundation drilling systems over the past 25 years. As the alternative energy industry ventures into uncharted territory of deeper water for offshore wind farms, fast current regions for tidal energy, and increasingly challenging soil conditions and project complexity, the advancement and development of new innovative equipment system and drilling techniques have become a necessity.The systems described herein show the development of the so called “FLY-Drill” system, and the all new “Seabed-Drilling” equipment applied at the first ever made job using a seabed drilling rig.FLY DRILLThe FLY DRILL method is a completely new concept for bored piling. The drilling unit with rotary head, Kelly bar, and drilling tool is suspended by the hoist rope of the base carrier crane. The hydraulic power for the drill unit is provided from the base crane.The drill head is fixed on the casing with a hydraulically operated clamping system during the drilling operation. When emptying the drilling tool, the clamp cylinders are opened and the complete unit is swung sideways."

Jan 1, 2017

By Padmavathi V, M. Najamuddin, M. R. Madhav

Granular piles are one of the leading ground improvement techniques, adopted for the betterment of bearing capacity and reduction in settlements of the foundations and also to accelerate consolidation of the surrounding soil. In the recent past, there has been extensive research on the settlement analysis and behavior of granular piles under varied soil conditions. The application of these theoretical solutions to practical problems requires a knowledge of representative values of the deformation parameters of the ground and the granular piles. However, very little information is available on these parameters. The paper presents a new method for the estimation of the modular ratio of granular piles and modulus of deformation of the surrounding in-situ soil from the compression load tests. The load - settlement response obtained from the compression test results are used in the back analysis for estimating the modulus of deformation of the ground. The presence of granular bed, under the rigid plate for load testing, has been given due consideration in quantifying the proportion of load transferred on to the stone column. Based on these considerations a new method is developed to estimate the modulus of deformation of the ground and the modular ratio of the granular pile.

Sep 1, 2022

By D. Dreher Whetstone, Paul M. Blakita, Christopher M. Reith, Ravi P. Malviya

"Micro-piles are small diameter (5 to 10 inches), cast-in-place piles which can develop high load capacities by bonding with soil or rock. Micro-piles are particularly well-suited for moderate to heavily loaded structures requiring deep foundations in difficult subsurface conditions, such as karst, bouldery mine spoil, or unsuitable fills with concrete debris or other obstructions. Attempts to install conventional deep foundations including driven piles, drilled piers, or auger-cast piles are likely to be fraught with construction difficulties and disputes, delays, cost overruns, and may be unfeasible in some cases. Micro-pile installation equipment is very effective in installing foundations through such overburden or rock materials.This paper presents case histories of Micro-pile installations on two projects with difficult soil/rock materials. The project sites are located in Charles Town, West Virginia and Masontown, Pennsylvania.Charles Town, West Virginia ProjectThe Charles Town project entailed construction of a four-story pre-cast concrete garage. Triad Engineering, Inc. performed a geotechnical investigation for this project (Triad, 2001). The subsurface, geologic, and project specific information described in th is paper are largely based on the aforementioned geotechnical report.Ground ConditionsThe project site is located in Jefferson County, West Virginia, and is mapped to be underlain by the Elbrook Formation. This formation is described as argillaceous, dolomitic limestone with beds of dolomite and aphanitic and algal limestone (Dean, et al. , 1990). The carbonate rocks at the site were characterized as ""moderately solution-prone, highly calcareous and weathers differentially to produce a pinnacled or ""sawtooth"" top of rock profile. (Triad, 2001 )"" Overburden soils consist of low to high plasticity, fine grained residual soils formed by weathering of the parent carbonate rock. The residual soils include variable proportion of sand and rock fragments."

Jan 1, 2005

By Brian Metcalfe, Kord Wissmann, Gianni Martinez

The Middle East consists of vast deserts that reach temperatures up to 50 degrees Celsius, with some areas characterized by endless sand dunes. When the project team selected the location for a large new transportation project, little did they know that the site would be characterized by soft, nearly normally consolidated silt and clay extending below a thin sand crust. Searching for solutions, the design team elected to reinforce the subsurface with Rammed Aggregate Pier® (RAP) ground improvement elements and desired verification that the novel method would stand the test of prolonged static loads. Because the concrete pavements would serve to spread the load, a “zone load test” was performed, consisting of applying a uniform bearing pressure of 150 kPa over a 7.5m square concrete footing. Unlike individual pier load tests, the zone test allowed the project engineers the opportunity to confirm design parameter values under large-loading area conditions, a situation not often available to most designers. This paper presents the results of the zone load test whose results may be interpreted to better understand design parameter values. This paper is of particular significance because it adds a value contribution to the relatively few numbers of “group load tests” available in the literature for ground improvement applications.

May 1, 2022

By Graeme Smart, Thomas Fiala

"Yorkville Plaza II, a 40-storey signature condominium residence, is scheduled to open on Avenue Road in Toronto’s prestigious Bloor-Yorkville neighbourhood in spring 2017. In close proximity to Toronto’s subway system, the new tower requires six levels of underground parking, founded in wet, silty sand.Isherwood Geostructural Engineers (Isherwood) was retained in April 2012 by developer Camrost-Felcorp to provide a shoring and excavation solution to address the challenging site conditions. A 31-storey upscale residential building under renovation with three levels of parking, owned by Camrost-Felcorp, flanks the site on the north. Situated on the eastern border is a 7-storey building with three levels of parking. Avenue Road, a four-lane arterial road that brings heavy commuter traffic into downtown Toronto, runs along the western border, and on the southern border of the site is a busy City road that brings traffic into the popular Yorkville area. The tunnel for the Toronto Transit Commission’s (TTC) overburdened east-west subway is located 14.5 m to the south, running below an existing 26-storey neighbouring building. Electrical and communication utilities (Bell) are closely located along the southern side. Non-documented existing excavation shoring, installed in the early 1970s, on the southern and western sides compounded the difficulties presented by the TTC tunnel.This paper presents the unique, non-conventional hybrid shoring solutions Isherwood developed to address the challenges presented by the site, as well as other complications that surfaced during the project: non-encroachment requirements (no tiebacks) beneath uncooperative neighbours, tight geometry to install shoring, and Toronto’s two coldest winters in decades.THE PROJECTBecause of circumstances associated with this site, for this project Isherwood designed two unique shoring walls which drew on their experience and expertise they had gained over the last 40 years. The following is the story of this site:Yorkville is an affluent neighbourhood in the heart of Toronto with a vibrant mix of high-rise towers, residential homes, tony restaurants and flagship shops. The development requires six levels of underground parking (a 20m deep excavation), with three levels undermining the high-rise buildings to the north and east and extending into wet, silty sand.Isherwood was retained in the spring of 2012 to design the excavation shoring. Isherwood’s scope also included field support, design, verification and monitoring. Finite Element Analysis was employed to confirm Isherwood’s design and anticipated movement of the south shoring wall and the TTC subway tunnel.The existing site was severed in two, with the proposed condominium tower slated for the southern portion. On the north half of the site stands a 31-storey building (Yorkville Plaza I at 21 Avenue Road), with three levels of underground parking, sitting on belled caissons which were one foot from the back of the proposed shoring wall so this would have to be considered in relation to the design and drilling methods. Constructed in the early 1970s, Yorkville Plaza I is currently being converted from the Four Seasons hotel to luxury condominiums by Camrost-Felcorp. To the east, directly adjacent to the proposed shoring, stands a 7-storey building (164 Cumberland Road) with three levels of parking, supported on spread footings founded on stiff clayey silt. The tunnel for the TTC’s busy east-west subway, a double box structure built by cut-and-cover in the 1960s, is located 14.5 m to the south, 9 m below grade, and running below an existing 26-storey building. Bell fibre optic communication cables and electrical lines, along with storm and sanitary sewers, are situated on the south and west sides of the site, leaving limited room to install shoring. Due to the heavy volume of commuter traffic on the four-lane arterial road (Avenue Road) to the west, site access and lane closure were not permitted here."

Jan 1, 2015

By Dan Brown

Renewal and revitalization of transportation presents a challenge in the need for replacement, repair, and improvements of existing bridges, as well as increased construction of transit systems within existing transportation rights of way. Difficulties with conventional deep foundation systems occur because of the limited site access, adjacent structures, the need to maintain traffic, and other constraints on construction activity. Major projects are often performed in a design-build contract environment in which the schedule is aggressive, and where speed and reliability represent major considerations. Foundation designers are confronted with a need to solve problems with a construction-oriented mindset, where typical experience with lowest cost solutions may not reflect the most effective approach. This presentation presents an overview of the challenges that may affect design and construction of deep foundations in this environment and the methods that have successfully been employed on several large transportation projects in the U.S.

Jan 1, 1900

By Jim Slatter, Ben Collingwood

"It is well known that the adoption of an appropriate construction methodology is critical to quality outcomes for bored piles (drilled shafts). Many case studies have been published documenting quality issues that have arisen due to a range of causes involving ground conditions, ground support, drilling and cleaning techniques, groundwater, concrete properties and concreting methods, amongst other things. Despite the body of published information, pile defects remain common in practice. The authors share over 40 years’ experience in the Australian piling industry and have participated in many hundreds of projects involving bored piles in design, construction and testing roles. It is the authors’ experience that many defects are caused by conditions or practices that are known to be problematic, but that are often not recognised or addressed at the time of the works. This paper provides an overview of industry practices and key factors relevant to quality outcomes. The authors draw upon their own construction experience, published case studies and guidelines, and observations from independent pile testing activities they have been involved in across the Australian piling industry. The intent of the paper is to provide a consolidated review of typical industry practices and to highlight key areas in which construction quality can be enhanced.INTRODUCTIONThere are many published studies of cases where bored piles have been constructed and found to have concrete defects. The authors have had personal involvement in many cases where the outcomes and learnings are not publically available. The nature and cause of defects is always dependent on site and project specific factors, and therefore methodologies and materials that produce satisfactory outcomes in certain circumstances may be problematic elsewhere. The process of bored pile construction encompasses the following key areas:??excavation and ground support;??pile preparation and cleaning;??pile reinforcement and fitments.??concrete supply and mix performance;??concrete placement methodology;Each of these elements is equally important and can influence construction quality in completed piles. In the authors’ experience, it is often a combination of seemingly minor issues that leads to significant defects in piles. Conversely, attention to detail in all aspects of bored pile construction is required to produce outcomes of a consistently high standard."

Jan 1, 1900

By Yu Chuang, Zai Jinmin, Liu Songyu

"The piled raft foundation is a geotechnical composite construction method, consisting of three elements, piles, raft and soils, which is applied for the foundation in an increasing number. Differential settlements have numerous negative effects on a superstructure in piled raft foundations. Through the analysis of the production mechanism of differential settlements and differential settlements control measures, a method of adjusting pile configurations is presented to control differential settlements. By comparing the measured data and finite element method analysis of one oil storage piled raft foundation, the new method is verified that the differential settlements can be reduced effectively and the inner forces of foundations are more reasonable with varying length pile configurations. The differential settlements can be minimized or even reduced to zero with right pile length.INTRODUCTIONPiled raft foundations are widely adopted for the prominent advantage of limited settlements and adequate bearing capacities. However, there always exits differential settlements in conventional piled raft foundations. The differential settlement is the main cause that produces additional stresses in the structure. Differential settlements have numerous negative effects on a superstructure as well as on a foundation, and should be restricted to allowable limits. How to control the differential settlement is the key interest.An increasing number of structures are founded on piled rafts. For this reason, design strategies that enable an optimized design have a major importance for safety and economy. An optimized design may be defined as a design achieving maximum economy of the solution, that is minimum cost for the installation of the foundation."

Jan 1, 2005

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 Todd Nottingham

Channel deepening of major ports is challenging designers to explore innovative solutions to ensure stability of bulkheads, such as for the Oakland Inner Harbor. This particular challenge was met with the use of the SPIN FIN® Tension Pile for restraint of an HZ combination wall along the Oakland Inner Harbor Shoreline in Oakland, California. A SPIN FIN pile is a pipe pile with welded plates at the pile tip that increase pile capacity. A brief history of the project will be provided as well as results of pile load tension tests, pile strain gauge, and wall deflection under construction loads. Tension pile load deflection results will be discussed with recommendations toward establishing deflection-based ultimate load criteria. A discussion of predicted wall loads and field observed wall loads will be provided.

Jan 1, 2008

By V K. Panwar, Sampat Raj

At a Fertilizer plant located in the southern part of India, 74 numbers of pump foundations have shown non-uniform settlements causing the tilting of pump foundations under self-weight primarily due to the presence of varying thickness of the heterogeneous subsoil beneath the pump foundations and soil erosion because of water seepage through deeper excavations in the close vicinity. Various corrective measures have been explored and taking due cognizance of the prevailing subsoil conditions, site constraints, and constructability aspects, micropiling has been adopted. This paper presents the site problem and details of remedial measures adopted for rehabilitation of the distressed pump foundations. The main objective of this paper is to provide guidelines for designer during design and detail engineering stage to avoid similar nature of problems and also to provide a solution concept to tackle similar nature of problem(s) if encountered at site.

Nov 1, 2022

By George K. Burke

Underpinning of a structure has been traditionally expensive, time consuming, and, in many cases, caused as much settlement to the existing structure as it was trying to prevent. As underpinning is normally one of the initial tasks and on the critical path on a construction project, there is immense pressure on the subcontractor to speed up his operation so the new structure can proceed; this can cause an adversarial relationship to develop between the owner, engineers, general contractor and subcontractor. Since its introduction to the North American market in the late 1980's, Jet Grouting has not solved all these problems, but where utilized, has shown economical benefits, a faster and safer installation, and a minimal movement of the structures being underpinned. A history of the development of jet grouting is presented; a comparison of this technique versus other grouting methods, a description of the jet grouting system with emphasis on the triple rod systems; case histories of jet grouting used for underpinning and conclusions and references are included to follow the program's themes of: - Recognizing Solutions to Today's Problems - Defining Tomorrows Challenges - Putting America on a Solid Foundation

Jan 1, 1991

By Jared M. Green

This paper presents the wall stabilization design and implementation for a 541 linear ft masonry and concrete gravity-type retaining wall flanking the west perimeter of a 7.37 acre parcel in Bronx, New York. This paper will discuss the results of static and dynamic stability analyses performed for the pre- and post excavation phases for the proposed 300 ft wide open-cut of up to 14 ft of contaminated soil below the toe of the retaining wall. The wall stabilization consisted of over 74 inclined drilled and grouted anchor dowels, and 55 tiebacks drilled and grouted to the underlying mica schist bedrock. Three over-lapping rows of jet grout columns were chosen as the foundation solution for the existing retaining wall. This paper focuses on the design, construction and performance of the jet grout curtain wall. The jet grout wall served three purposes: 1) underpinning and excavation support for the removal of contaminated site soils, 2) permanent hydraulic barrier, and 3) resistance against a deep seated failure within the thick clay layer present at the site. The originally designed jet grout wall had unexpected negative effects to the existing retaining wall. The jet grouting program was modified while the Observational Method (Peck 1969) was employed to keep wall movements to a minimum. This paper discusses the diagnostic methods used to determine the cause of retaining wall movement; the implementation of a remedial ground improvement program; the modification to the jet grout installation procedure; and the ultimate performance of the jet grout wall.

Jan 1, 2011

By Franz-Werner Gerressen

"The use of soil improvement to utilize areas, which are not suitable for foundation purpose, has a long tradition. Due to the increasing demand of foundation works in areas of unsuitable soils, the improvement of the existing soils becomes even more important in the future.Various applications and systems for various demands exist around the world. Either it is a “simple” improvement for settlement reduction or a more important aim as liquefaction mitigation. However, each system has its advantages, limits and needs.Furthermore to the soil improvement, using various tools, soil mixing can also be used for applications like cut off and/or retaining wall.The paper will describe some basics of various techniques and different applications of the systems all over the world where the systems provided solutions for different purposes, e.g. simple foundation or liquefaction mitigation.It will describe also the main equipment which will be needed to execute these works under the various conditionsINTRODUCTIONSoil mixing is a methodology where the soil is improved by mixing it with cement, lime or other binders in situ by using a mixing tool. This methodology can be used either as wet mixing or as dry mixing. In the more frequently used wet mixing process, usually a mixture of binder and water, maybe with additives, is injected and mixed with the soil. Depending on the type of soil and binder, by the end of the mixing process, a mortar like mixture is created which hardens during the hydration process. In the dry mixing process, the binder is directly mixed with the soil and reacts directly with the existing soil and water.Mixing tools show several versions, so that they are mixing around either a vertical or horizontal axis, mixing in a trench and maybe are jet assisted. Figure 1 shows a classification done by Bruce 2010. Depending on the technique, improvement depth of up to 80 m can be achieved."

Jan 1, 2017