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By Keithe J. Merl, Brendan FitzPatrick, Gregg Piazza

Urban and industrial construction projects commonly involve interior work within buildings, warehouses and manufacturing facilities. Renovations of these existing structures must address both structural and geotechnical engineering challenges while also balancing the practicality of implementing solutions within site constraints including limited site access, overhead clearance restrictions, vibration tolerances and uninterrupted facility operations. This paper highlights two projects for an international shipping company where mezzanine level additions within active shipping facilities required construction of new foundations. Construction requirements included low vibration levels, as well as rapid and clean installation to limit impacts on the active shipping operations. The selected system also needed to adjust to both variable ground conditions and differing overhead clearances. This paper describes the installation, design and performance of Ductile Iron Piles used to meet the project challenges. The low vibration, driven pile system offered the ability to work within restricted overhead environments while successfully delivering working compression capacities ranging from 45 to 75 tons (41 to 68 tonnes) as well as lateral and tension resistance. The paper also presents the results of site-specific load testing (and pile capacity) for various termination criteria. INTRODUCTION Urban and industrial construction projects commonly involve interior work within buildings, warehouses and manufacturing facilities. Renovations of these existing structures must address both structural and geotechnical engineering challenges associated with the new construction. Foundation solutions must also balance the need to achieve design requirements with the practicality to be installed within the particular site constraints including limited site access, overhead clearance restrictions, vibration tolerances and uninterrupted facility operations.

Jan 1, 2019

By Monica Prezzi

"Auger cast-in-place (ACIP} piles and drilled displacement piles are being increasingly used as foundation elements for structures, particularly in projects requiring accelerated construction or involving the rehabilitation of foundations of existing, overstressed structures. Auger cast-in-place piles (also referred to as continuous-flight-auger piles) are widely used to construct the foundations of all types of structures. There are many different types of drilled displacement piles, with the installation methods varying according to the equipment used. Depending on the specific rotary piling technology used, responses ranging from those associated with non-displacement to those associated with full-displacement piles are obtained. Conventional pile design methods do not account for how the various construction techniques involved in auger piling change the soil state around the pile during installation and, hence, cannot accurately estimate the pile resistance in a consistent way. Research on this subject, identifying the different variables that must be accounted for in design and linking these variables to installation methods, is lacking. This paper describes the different piling methods available for auger cast-in-place and drilled displacement piles, the equipment used to install them and the quality control processes typically used. It also reviews some of the design methods currently used.IntroductionDeep foundations are extensively used in geotechnical engineering practice. The wide spectrum of piling methods results in a variety of pile types. Each type behaves differently, depending on the installation or construction methods. On one end of the spectrum are non-displacement piles, the classicql examples of which are bored piles or drilled · shafts. These piles are constructed by removing a cylinder of soil from the ground and replacing it with concrete and reinforcement. On the other end are full-displacement piles, such as closed-ended pipe piles or precast reinforced concrete piles, which are typically driven into the ground. Driven piles preload the materials below the toe of the pile and displace the soil surrounding the pile shaft laterally during the installation process. Therefore, displacement piles are, in general, more likely to have a stiffer response than non-displacement piles. This is true particularly in the case of sandy soils where displacement causes densification."

Jan 1, 2005

By Tracy Brettmann, Melis Sutman, C. Guney Olgen

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

Jan 1, 2017

By Shoji Higashi, Nobuhiro Honda, Takeo Asanuma, Tatsuo Nagatsu, Masaki Kitazume, Sachihiko Tokunaga, Shigeru Kubo, Hidenori Takahashi, Tsuneyasu Onishi, Yoshiyuki Morikawa

"Various kinds of civil engineering structures and facilities were seriously damaged in the earthquake in Tohoku and Kanto regions of Japan on 11 March 2011 due to the greatness of its magnitude. In contrast, many structures resisted the large seismic force having been reinforced by the CDM (Cement Deep Mixing) method, which is often used for increasing the bearing capacity of ground and improving seismic performance. This paper summarizes the field survey undertaken to investigate damage to structures and facilities reinforced by the CDM method. Several prefectures and metropolitan areas were selected for the survey, based on the occurrence of strong seismic motions. A total of 847 structures and facilities were studied, in the survey using a questionnaire, which mainly inquired about the appearance of structures and facilities. Of the respondents to the questionnaire, 789 replied that there were no seriously damaged structures. The paper presents the damaged and non-damaged sites of CDM-technique sites and non-CDM-techniques sites. It can be concluded from the field survey that the CDM Method demonstrates high efficacy and durability against a strong seismic motions.INTRODUCTIONDuring the afternoon of 11 March, 2011, a huge magnitude-9.0 Mw (Category 9.0 on the Richter scale) earthquake occurred about 25 kilometers below the Pacific Ocean’s surface off the coast of Tohoku. This massive earthquake, now called the 2011 Off the Pacific Coast of Tohoku Earthquake was the largest earthquake ever observed in Japan. The seismic intensity of this earthquake was measured 7, the maximum on the Japanese intensity scale, as observed 7 in northern Miyagi Prefecture. The earthquake caused severe damage over a wide area from Tohoku to Kanto, and triggered large tsunamis that struck the Pacific coast of Hokkaido, Tohoku, and Kanto. The number of missing and fatalities caused by this earthquake exceeded 18,000 persons, making this an unparalleled earthquake disaster with a cost-in-life toll not experienced by Japan in recent years. Because of the scale of its seismic motions, the earthquake damaged facilities and structures of many kinds. In the years prior to this earthquake, the CDM method was used extensively to increase the bearing capacity of the ground as an anti-seismic countermeasure and to prevent liquefaction. Immediately after the earthquake, the CDM Association visually surveyed the state of damage to about 800 facilities in the Tohoku and Kanto regions where a seismic intensity of 5 or higher was observed. This report summarizes the survey of damage to facilities and structures constructed applying the CDM method in order to confirm the durability and performance of the method against seismic motions."

Jan 1, 2015

By Toshio Yonezawa, Helmut Florian, Herbert Kuh, Masamichi Aoki, Takao Koono, Franz-Werner Gerressen

"To increase the bearing capacity of the ground, soil improvement technique is often adopted. One advantage of soil improvement techniques is the fact, that the impact to the environment is low, as the system utilizes the existing soil. Recently, compressive strength of soil improvement gets more into the focus for the use of building foundation. To prevent brittle fracture, which is a weak point of soil improvement, fiber reinforced soil improvement has been developed. Laboratory tests were conducted to examine the fibers suitable for reinforced soil improvement, and examine the optimum mix design for fiber cement slurry. Based on the laboratory tests, polypropylene fiber and cellulosic viscosity admixture was selected. For the laboratory tests a scaled model of CSM mixing head was used to examine the dispersion of the fibers in the ground. Using the CSM mixing head, the outer periphery fibers of soil improvement seemed to be arranged in the vertical direction, toughness performance of the soil improvement could be improved. Furthermore, full scale field test was performed using actual CSM unit, modified to enable the use of fiber mixed slurry. The validity of the material as well as the toughness performance of the soil improvement, determined from lab test results, was confirmed. In addition, it was confirmed that fiber reinforced soil improvement can be constructed appropriately by CSM method.2 INTRODUCTIONSoil improvement technique to improve the strength and deformation performance of ground has been used for a long time. Cement improved methods, with the increase of the deep Mixing Method, which has been disseminated since the 1970's, was often used since. Cement used soil improvement technology has been utilized to stabilize excavations, slopes in embankment and much more. Recently, it can be used for preventing liquefaction by building soil improvement in a grid (Suzuki et al. (1996)), and also as basis of the structure by increasing the compression strength of soil improvement (Yamashita et al. (2011)). Cement used soil improvement method, a technique for mixing the in-site soil and cement, can effectively utilize natural resources, and it can be expected that its use will increase further in the future. Therefore, soil improvement technique will be able to minimize the impact on the environment. Cement improved soil is a mixture of soil particles and cement with high compressive strength but low tensile strength. Since tensile strength of soil improvement is low, brittle destruction occurs. Therefore, it is not possible to use soil improvement in conditions acting with bending stress. If a horizontal impact force occurs in the improved soil, the width of the soil improvement needs to be increased to reduce the bending stress. If preventing the brittle fracture of soil improvement, the width of soil improvement could be reduced, then less resources would be needed. In order to increase the tensile strength of the soil improvement, several studies for the mix of fiber and soil were performed. Victor (1992) indicates cracking deterrent effect by fiber based on laboratory tests. Moreover, based on laboratory tests, Hayasaki (1982) illustrated the effect on the tensile strength of the fiber types, the type of fiber, the diameter of and the length of fiber."

Jan 1, 2015

By Vivian M. Troughton, Clifford J. Wren, Tony P. Suckling

"Secant pile walls are used for the construction of deep basement walls and earth retaining structures. Risk associated with secant pile walls is commonly perceived as being the safety of site personnel and the public during piling operations, or safety used in design. It is recognized that both of these are of paramount importance, but additional risks associated with the construction methods must also be considered to complete the risk management profile for any project. For the particular case of secant pile walls, if Clients take a ""back seat"" they may be unaware of the total risk package they are procuring. The authors argue that the piling contractor should be involved at the earliest stage giving input into the overall risk management process. Such early involvement within the professional team will maximise cost benefits to the Client and minimise the delays and cost increases sometimes associated with these works. A consistent methodology for identifying and then managing all the risks associated with secant pile walls is proposed. An example is used to demonstrate how this methodology should be employed. INTRODUCTIONThis paper discusses the value of a complete and integrated risk management process for structures with basements formed using a secant pile wall.The risk associated with any secant pile wall can be consicfered as comprising four components;1. Safety of people on site2. Safety of design or design methodology3. Construction risks4. Commercial risksAny risk management system needs to fully consider and integrate each of these four components to maximise the likelihood of a successful outcome for the basement.This paper concentrates on the construction risks for secant pile walls, as these are not often understood by the Client (in this paper the term ""Client"" also includes the main contractor, principal contractor, Engineer, Planning Supervisor, quantity surveyor and cost consultant)."

Jan 1, 2005

By M. Krzaninski, Y. Zou, A. Frost

The foundation solution for a data centre building in Sydney, Australia comprised two alternatives, the first of which incorporated the use of CFA piles founded in rock at approx. 27m depth to support column working loadings of approx. 7.5MN, and the second utilising rapid impact compaction with a raft foundation of 1.0m thick concrete slab. Soil conditions comprised 1m of fill over 3 to 4m of sands varying from loose to dense consistency, underlain by very stiff clays overlying the rock. A creative solution incorporating Rapid Impact Compaction to improve the loose soils in conjunction with a piled raft solution was proposed. Piles proposed under the raft were Atlas Drilled Displacement piles which offered advantages of displacement pile performance and savings in time and material costs. The piled raft solution was developed in consultation with the consulting structural engineer, combining the skills of the piling contractor and consulting engineer to the benefit of the project. This paper describes the development and design aspects of the piled raft solution adopted for the project.

Nov 1, 2022

By Onur Guvener, Kalaiarasi Vembu, C. Vipulanandan

"Installation procedure and the quality of the material used in the construction have significant effects on the behavior of the Auger Cast in Place (ACIP) piles. In this study, Installation and curing of a 760 mm (30 in.) diameter and 12 m (39 ft) long ACIP pile with a design capacity of 1140 kN (128 tons) in hard clay was investigated. Construction quality was monitored using the automated monitoring system where the volume of grout pumped and the pressures were monitored with depth. The curing of the pile was monitored using axial vibrating wire strain gages at four levels and lateral vibrating wire strain gages at two levels. The residual strain and temperature profile in the curing pile was monitored over a period of week to determine the appropriate time for load testing the pile. Axial behavior of Auger Cast in Place (ACIP) Piles in hard clay was studied using full scale load test on an instrumented pile. The load-settlement and load transfer relationships of the pile was investigated based on the load test results. Development of skin friction in the load test pile and the reaction pile was also investigated.INTRODUCTIONAugered cast-in-place piles (ACIP) are drilled foundation installed by drilling a hole with a continuous flight auger to a predetermined depth. Non-displacement Augered Cast-in-Place (ACIP) piles are increasingly used for supporting building, bridges, sound barrier walls and many other structures around the world. In an ACIP pile, depending on the soil type and rate of the auger advance, ground stresses are maintained near the value that existed before construction by using a continuous flight auger, which is never withdrawn until the cementitious material (fluid Portland cement grout) is placed by pumping the grout beneath the withdrawing auger under pressure through the hollow stem of the auger (Vipulanandan, 2005). ACIP piles are typically installed with diameters ranging from 0.3 to 1.0 m and lengths up to 30 m (Brown, 2005) although longer lengths have occasionally been installed. Comparing to the drilled shafts and driven piles of equivalent size ACIP piles can be installed more rapidly with fewer disturbances to the surroundings in favorable geological conditions. Hence the installation procedure and the quality of material used in the construction have significant effects on the behavior of ACIP piles (Vipulanandan, et al. 2007). In this paper construction quality control technique for ACIP piles was investigated. Load displacement and load transfer behavior of pile in compression and tension in hard clay was also studied. The development of side resistance in compression and tension for the load test piles and the reaction pile were also investigated."

Jan 1, 2017

By Brian M. Fraley

"Portions of the Catholic Total Abstinence Fountain in Fairmount Park in Philadelphia, Pa., were in “imminent danger,” according to a restoration services request for proposals (RFP) issued by the City of Philadelphia in August 2014. Open voids in the subsurface beneath the foundation were causing ongoing settlement of the fountain.The fountain was unveiled in 1876 as an ornamental drinking fountain for the Centennial International Exhibition, which celebrated the signing of the Declaration of Independence. Its creation was commissioned by the Catholic Total Abstinence Union of America, an Irish temperance organization that advocated for total abstinence from alcohol. Ironically, the fountain ran dry decades ago.The now-defunct fountain features a 100 ft (30.5 m) wide granite base with three steps in the shape of a Maltese cross. The centerpiece — enclosed by a 40 ft (12.2 m) diameter basin — is a 15 ft (4.6 m) tall statue of Moses perched atop an iglooshaped marble mound. Four subsidiary statues rise from granite pedestals at the tips of each arm of the cross, including Archbishop John Carroll, Charles Carroll of Carrollton, Father Theobald Mathew and Commodore John Barry.Natural and Man-Made DamageThe City of Philadelphia’s RFP called attention to three “high priority structural areas.” It was noted that Moses, Father Mathew and the steps surrounding the fountain had been documented as public hazards. The long-term effects of water infiltration had set in, eroding mortar joints and causing some stones to jut out. Furthermore, the stone base supporting the 16 ton (14.5 tonne) statue of Moses was in danger of collapsing. The statue of Father Mathew had been struck by lightning in 1910 and was repaired with an iron and metal pin anchor system, which had succumbed to corrosion. The city considered the statue of Father Mathew as the most threatened of the statues. Mike Miluski, P.E., vice president of Compaction Grouting Services (CGS), recalled “the fountain was in pretty bad shape” as he walked onto the site in August 2016 and immediately recognized the challenges ahead."

Jan 1, 2017

By Eleonora Di Mario, Colin B. Turnbull, Matthew G. Mills, Chengbin Miao, Wilhelm S. Degen

"In the past decade, the ‘zero-dredge’ philosophy has become the preferred option for the formation of marine seawalls and reclamations, compared to the partially or fully dredged options, as this solution presents several environmental advantages. Recent relevant project experience is presented herein in order to highlight key design principles and construction issues central to the successful construction and performance of a sloping rubble seawall founded on soft soil improved by stone columns. If designed and installed with proper quality control, correct treatment intensity and sensible construction staging, stone columns are a safe and cost effective method for seawall foundations. This paper provides guidelines with regards to the design, construction and quality control for the correct implementation of stone columns as a foundation element for sloping rubble marine seawalls.INTRODUCTIONBenefits of sloping marine seawalls founded on stone columnsTo suit the current environmental requirements in Hong Kong, recent projects are tending to favour zero-dredge solutions, such as the Hong Kong Boundary Crossing Facility and the forthcoming Three-Runway System. The installation of stone columns allows the underlying deposits, generally consisting of very soft to soft clay and silt (soft soil), to improve in strength to the extent that the seawall can be directly placed on the seabed. This negates the need to dredge the soft soil and, therefore, this ground improvement technique represents an ideal solution for zero-dredge projects.Stone columns can also provide several other beneficial effects, including: accelerated drainage, reduced settlement, increased slope stability and soil reinforcement in the event of an earthquake. Stone columns, in contrast to competing cementitious methods, are a very ductile foundation method. This ductile behaviour is part of the design concept of stone columns in soft soil. Past projects located in Hong Kong and elsewhere, with an improved soft soil layer thickness of over 15m, have shown that stone columns can remain fully functional in terms of both drainage and horizontal reinforcement, even after settlements of over 3m and lateral displacements of up to 1m have occurred."

Jan 1, 2017

By Shahid Islam, Lucian Bogdan

"The maintenance of infrastructures has been of particular concern to the engineering community. As the world’s infrastructure expands and existing infrastructure ages, monitoring and evaluation of the structures have become more critical than ever. A large number of retaining walls, tie backs, slope stabilizations and piles are designed using pre-stressing steel. Many piles and drilled shafts are designed using reinforcing steel. There are few testing methods available to assess these tension and compressive forces. High cost, complicated equipment and limitation of space often prevent these methods from being implemented. DYWIDAG-Systems International (DSI) has been involved in the development, testing and utilization of DYNA Force® sensors to measure the force in the anchors during construction and at any time during the lifetime of the structure. They can be used for bare, epoxy-coated, galvanized and greased-sheathed steel in the bonded, un-bonded, grouted or un-grouted length of the anchor. The sensor is robust and requires no maintenance. Sensors have received attention in terms of accuracy, performance, ease in installation, durability, and cost effectiveness. This paper describes its application in tie-back and anchor force monitoring of retaining walls and bridge abutment and compression forces in drilled shaft reinforcing steel where the data were collected manually, automated and remotely.INTRODUCTIONOur infrastructure is expanding and the existing infrastructure is aging. Some structures are expensive to maintain and some occasionally fail. There is a large demand for implementing health monitoring of structures. Many tie-backs, retaining walls, dams and other geotechnical structures are post-tensioned and many of them need repair using a post-tensioned system. On many occasions during construction and service life of the structure, it is useful to know the force in the post-tensioning and anchor system. Many piles and drilled shafts are designed using reinforcing steel and the compressive forces in reinforcement are unknown. Although there are many methods to measure the tendon force, most of them are cumbersome, expensive, and the accuracy varies depending on the method used.The elasto-magnetic (EM) technology is a novel approach to monitor forces in steel elements. The DYNA Force sensor is built based on EM technology (See Fig. 1). It is composed of a primary coil and a secondary coil (sensing coil). By passing current through the primary coil, ferromagnetic material is magnetized. The sensing coil picks up induced electromotive force that is proportional to change rate of applied magnetic flux (Faraday's law) and relative permeability. As permeability of core changes, output voltage changes. The output voltage is calibrated to measure the force. A readout unit is designed to magnetically energize the steel through the sensor and measure the response of the steel to the process. The readout unit then converts the response into a direct force reading. The sensor has an embedded thermistor which allows for temperature compensation. Due to the diversity of the magnetic property of steel, calibration is done for each type of steel allowing the sensors to perform at their highest accuracy."

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 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 Rouzbeh Vakili, Adel M. Hanna

"The application of piled raft foundations has significantly increased during the last few years. In this system, the raft and the pile group collectively transfer the applied building load to the underlying soil layers. Determination of load sharing between the raft and the piles derives the complexity of piled raft designs due to its multi-parameter nature. These parameters are but not limited to: soil density, pile length, pile spacing, raft geometry, and piles installation technique. This study is to examine experimentally the effect of sand density and pile installation techniques on the load sharing mechanism. Experimentally, tests were conducted on a square rigid raft with a single pile in sand under three different soil densities; 30%, 45%, and 60%. The experimental results are used to determine the pile and the raft shares in non-displacement and displacement piled raft systems. The results of this study reveal that soil density changes the load sharing of displacement piled raft; the pile share increases in higher soil density. However, this is not the case in non-displacement piled raft and load sharing is independent of soil density in working loads.IntroductionThe piled raft foundation is a combination of shallow and deep foundation which transfers the superstructure load to the soil by a complex soilstructure interaction. The interacting mechanism among foundation elements and their surrounding soil is illustrated schematically in Figure 1 and could be classified into two categories: (1) pile-soil-pile and (2) pile-soil-raft. The pile-soil-pile interaction is the same as the free standing pile group and is a function of pile spacing and pile installation method. Pile-soil-raft interaction, which only involves in piled raft foundation design, could be affected by: the length, spacing, and roughness of the pile, the rigidity and dimension of the cap, soil condition, and the pile installation method. Pile-soil-raft interaction could have favourable and unfavourable effects on bearing capacity and settlement, respectively. The pressure between the cap and the soil favourably increases the horizontal stress on the pile shaft and consequently increase the shaft resistance. Whereas, this pressure induces negative skin friction on the piles which increases the settlement. The pile-soil-raft interaction mainly controls the load sharing mechanism of piled raft foundation when pile spacing (S) is more than 3.5dp."

Jan 1, 2017

By Dawn Shuttle

In trying to find a grout, or some kind of stabilizer that would work in this application, we established some performance criteria. Of those, what I controlled the most was viscosity, then I had a whole list of other criteria. I needed a long, controllable gel time, durability and the ability to set and stabilize the soil. So I looked through a lot of different stabilizers, some really crazy ones and also the typical chemical grouts that are used. The typical chemical grouts were eliminated because of long-term durability concerns, the need for having extended gel times, and several other concerns. I would be happy to discuss that with you further after the talk if you're interested. But, generally it was based on viscosity, gel time, and the need for extended gel time. In terms of the relative density of the sand many other grouts could have been used. But the main issue was trying to develop this way to do low pressure grouting that would not cause invasive disruption of the site. We couldn't go in and grout it, put centers, so most of the other grouts wouldn't work for various reasons. The forty percent relative density samples were prepared by plubiation. That was both during the cyclic testing stage of the research, which happened a few years back, and also during the box model and the laminar box models at RPI. In terms of what criteria were used to determine the success of the grouting, when I initially started this work what I did was take the grouted samples and I subjected them to cyclic triaxial testing. What I did was take a look at the cyclic deformation resistance of different concentrations of grouted colloidal silica treated sand. I looked first at 20% concentration because I wanted something that I knew worked and then I gradually decreased to 15%, 10%, and 5%. What I was most concerned with was that it did not liquefy and that it was able to hold together it and experience some deformation. But most importantly it needed to not liquefy. So, that was the biggest issue in determining the success of the grouting. In terms of the centrifuge modeling it was done by looking at several components: from looking at the pictures of the bending moments, looking at the acceleration records and how the acceleration records were transferred through the soil, looking at the reduction in the lateral displacement and those kinds of issues. So let me show you the difference.

Feb 10, 2003

By Alexi J. Neill

"This presentation will showcase two challenging projects with deep excavation support systems in the Atlanta area where state-of-the-art instrumentation and monitoring systems were used to manage risk by confirming design performance requirements / calculations during construction. The instrumentation and monitoring system successfully reduced risk by recording real-time data on a project website while simultaneously sending email alarms to key site personnel when data exceeded pre-determined alarm thresholds. The monitoring data revealed unexpected performance at an early enough stage so that contingency plans could be engaged and remedial efforts devised in order to limit the consequences. Finite element analysis was used to model deformations, analyze the unexpected performance, and prepare theremedial design.INTRODUCTIONConstruction in densely populated urban areas is becoming more common in order to keep up with the increasing infrastructure demands of our growing population. America’s big cities continue to outpace the overall nation in population growth. The city of Atlanta, the nation’s ninth largest city based on metropolitan population, is a prime example of this. The population has grown at a rate of 6.6% between 2010 and 2013, nearly triple the overall growth rate of the United States during the same period (SustainAtlanta, 2015).As a result of increasing infrastructure demands in Atlanta, developers are now constructing larger buildings on smaller properties. In addition, developers are attempting to maximize space on their selected properties, often by designing underground parking garages to accommodate as many cars as possible on these compact sites. In some cases the selected sites are adjacent to buildings, utilities, and other existing structures. The risk associated with construction increases during underground work that requires a support of excavation system, particularly on confined sites adjacent to existing structures. There is a risk posed to people, property, and the environment that the project team should monitor when constructing in these conditions."

Jan 1, 2016

By Kenneth Gavin, Weichao Li, Paul Doherty

"The lateral load capacity is one of the most important issues to be considered in designing piles to resist berthing loads, ship impact forces and for monopiles used in the offshore wind sector. A number of semi-empirical design approaches are available to calculate the ultimate soil resistance and assumed soil reaction profile along the piles’ embedded depth. In order to investigate the response of monopiles to lateral loading, a series of field experiments were conducted on instrumented steel pipe piles. Two lateral loading tests were performed on model piles with a diameter, D, of 340 mm and embedded depth, Lem, of 2.2 m, giving a Lem/D ratio similar to those adopted in the offshore wind sector. The piles were driven into dense sand at the University College Dublin geotechnical test bed site in Ireland. 10 pairs of strain gauges were installed on each model pile along the embedded depth at 10 levels to capture the load transfer and bending moment within the piles. The deflection and rotation at the model pile head were measured by Linear Variable Differential Transformer (LVDT) and inclinometers. The tests results were used to perform a detailed evaluation of current design methods. In the final section, discussion on the determination of the ultimate lateral load capacity for monopile design was conducted. IntroductionA pile’s lateral load capacity is determined, for design purposes, by two conditions: 1) the ultimate lateral load, Fu, divided by an appropriate safety factor; and 2) the load according to the maximum lateral deflection that the support structures can sustain. In view of the first condition, design methods to calculate the ultimate load were developed for piles used in the offshore oil and gas sectors, which tend to be much more slender than monopiles used in the wind industry. The purpose of this study was to investigate whether these design methods provide reasonable estimates of ultimate capacity, for short rigid monopiles.The methods to determine the ultimate lateral load generally follow three steps: 1) determine the ultimate soil resistance, Pu, along the pile embedded depth; 2) adopt the most appropriate soil reaction profile, Pz, along the piles embedded depth when the pile subjected to the ultimate lateral load condition (four of the most popular ones are depicted in Figure. 1); and 3) ensure equilibrium of lateral forces (see Equation 1, symbols are listed at the end of the paper) acting on the pile and bending moments (see Equation 2) about a point in pile is employed to determine the ultimate lateral load."

Jan 1, 2015

By Malek Smadi, Yazen A. Khasawneh

"New embankments were constructed mostly on soft clays as part of interstate I69 extension in southern Indiana. The embankments serve as bridge abutments and as part of the fill sections along the interstate extension alignment. The height of the embankments range from 50-ft to 125-ft with a maximum foundation thickness of about 75-ft. The foundation soils comprise relatively high compressible fine grained soils. A fully coupled Hydro-Mechanical numerical simulations were conducted for optimizing the construction stages of the embankments. The objective of the staged construction is to allow for sufficient effective stress and undrained shear strength gain to ensure foundation stability under the stage load. Wick drains were utilized to shorten the drainage path and thus accelerate achieving the required undrained shear strength. The extensive field investigation and laboratory testing programs provided a good understanding of the subsurface conditions and allowed the use of a relatively advanced soil constitutive model in the numerical simulations of the staged construction. The effectively designed instrumentation program allowed for monitoring the settlement and pore water dissipation during construction. The pore water pressure, and surface and subsurface settlements from the numerical model predictions reasonably agreed with the instrumentation data over the construction period.INTRODUCTIONThe stability of soft fine grained foundation soils due to embankment construction is dependent on the undrained shear strength of such soils. The permeability, compressibility, and drainage boundaries control the foundation soils response (settlement magnitude and rate) to loading. The settlement magnitude is a function of minerology and soil structure. The settlement rate which is equivalent to the rate of excess pore water pressure dissipation is a function of the soil permeability and drainage boundary. The dissipation rate control the evolution of effective stress and thus the gain of undrained shear strength. As such, if the increase in total applied load is controlled such that enough time is granted for the evolution of the total stresses into effective stresses, then the stability of the foundation soils is enhanced by the gain of the undrained shear strength. The controlled application of the total stress is the definition of the staged construction. From the definition of the staged construction, it is obvious that the process is a coupling of the hydraulic and mechanical responses of the foundation soils."

Jan 1, 2017

By Jim Bruce, Naresh Gurpersaud

"The West Toronto Diamond project, under construction since 2006 and due to be complete in 2015, is a rail-to-rail grade separation project in the heart of urban Toronto. Once complete, a depressed corridor over 1000 metres long will take the CN tracks beneath the CPR tracks. An interlocking steel pile wall serves to retain ground and cut off groundwater. Remedial measures, constructed using jet grouting, were required at several locations within and behind the steel piles.At mechanical interlock joints damaged or suspected of being damaged, jet grouting was used to improve native soils on the retained side of the wall to reduce permeability of the soil mass in intimate contact with the joints to 10-7 cm/s. At a number of steel piles where groundwater and soil type combined to cause basal instability inside the pipes during the interim between excavation and concreting, jet grouting was used to construct temporary bottom seals. At locations near adjacent structures where the steel pile installation process resulted in disturbed ground on the retained side of the wall, jet grouting was used to strengthen and stabilize ground.This paper outlines the details of the various jet grouting applications, the respective testing programs implemented to demonstrate in situ permeability and strength of the soil-grout matrix, and performance of the constructed system.INTRODUCTIONThe West Toronto Diamond (WTD) is a junction of several railway lines, all intersecting at the same grade (Figure 1). A major grade separation project at this site commenced in 2006 and is scheduled to be completed in 2015. The whole of the work is comprised of multiple contracts, completed and/or ongoing, by different constructors. Once completed, a depressed corridor over 1000 metres long with over 23,500 m2 (face area) of retained earth will bring the CN tracks beneath the CPR tracks and eliminate a major bottleneck at the most heavily used rail crossing in Canada."

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