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By Marcelo Chuaqui

We certainly have the data to back calculate it. I must admit that I haven't, at the moment my priority is not on what is the stiffness of the jet grout but is making sure that the jet grout is really there. It's a bit like what Stuart Littlejohn was talking about this morning in terms of grouting on the dams a small window causes a big problem so it's having the jet grouting there at all, at the moment must have been my focus rather than just what is the stiffness once you've got it there.

Feb 10, 2003

By James Warner

Although use of low mobility grout is just now beginning in some parts of the world, its advantage for many applications has been well established through more than 50 years of positive experience. The single largest area of application continues to be densification of soil by way of compaction grouting. Because it is often the safest and least costly method for soil improvement in general, and virtually always that in connection with soil improvement under, or adjacent to structures or in developed areas, use will undoubtedly increase both geographically and in diversity of application.

Feb 10, 2003

By Jamey Rosen, Georgette Hlepas

Verticality data collected from panel and pile elements of seepage barrier walls describe the shape and position of those elements in three dimensions. These data are used to determine if a barrier wall is constructed as designed and if it meets the owner specifications with respect to tolerance (i.e., if each element is sufficiently close to vertical) and overlap (i.e., do adjacent elements overlap sufficiently to prevent leakage). Contractors use verticality data to confirm that their work matches the design, and owners use verticality data to verify the contractor’s work and confirm that specified criteria were met. Project Information Management Systems (PIMS) technology has been applied to the management, visualization, and analysis of verticality data. This paper will provide examples of how contractors and owners have used a PIMS to compile and synthesize data collected during excavations (e.g., from Cutter Soil Mixer and Hydromill drill rig telemetry), and from measurements of completed excavations (e.g., using the Koden ultrasonic tool), and used those data to model excavation geometry. We will present case studies of using these models to estimate backfill placement volumes, and to evaluate the verticality tolerance and overlap between elements.

Sep 8, 2021

By John C. Ryan

The Emeca Pile Splice, an innovative mechanical prestressed concrete pile splice, is the first robotically welded splice to be fabricated in the United States. An analytical and experimental study was conducted to establish the capacity of the standard splice for 12-in. and 14-in. square piles. The study illustrates compliance of the splice with International Building Code (2006) requirements. A case study for a large petroleum tank foundation project in Port Canaveral, FL is presented, demonstrating the efficiency achieved through use of spliced-piles. For the case-study project, single-piece 18-in.-square, 100-ft-long piles were replaced with 12-in.-square, two-piece, spliced piles. As a result, a significant reduction of material, labor, handling, and equipment was documented for the project. Savings realized on the installed pile cost was estimated to be in excess of 30% by the owner.

Jan 1, 2010

"Premissas BásicasCaracterísticas do concreto centrifugado(Spun concrete characteristics)Aplicação em obras de engenharia de fundações(Application engineering works foundations)Logística de fabricação e transporte(Manufacturing logistics and transportation)Emendas x uso de aplicação(Amendments x use application)Geologia brasileira, da região costeira a presença de grandes bolsões de argila mole(Brazilian geology, coastal region the presence of large pockets of soft clay)Influencia do sistema de cravação(Influence of driving system)Transferência da Energia Aplicada(Applied Energy Transfer)Estacas longas(long piles)Controles executivos (diagrama de golpes, nega, repique elástico, ensaios de carregamentodinâmico, provas de carga).(Executive Controls (blows diagram, sets, elastic rebound, dynamic load tests, load tests).)ECD – aplicação da metodologia do DIETECD - application of the methodology DIETBrazil has a highly variable geology all along its coast that directly influence the choose of foundation type, being too employed the use of reinforced spun concrete piles initially ranged in diameter from 60 to 80 cm. Over the past 10 years with the advent of investment in marine works projects began to demand a new range of piles with diameters greater than 100 cm and in the absence of amendments.On land is also very remarkable the presence of regions with large layers of soft clay, in prime areas that have been explored. A classic example is the Barra da Tijuca in Rio de Janeiro that has suffered from the housing boom growing toward these regions. In these regions it has been very common driven lengths of about 40.0 meters, which basically go through thick layers of soft material or unconsolidated and they will find strength in depth with residual soil layers or even the bedrock.The spun concrete has great qualities for application in deep cuttings resulting from the production process, which gives a redistribution of fresh concrete mass collaborating with the particle size distribution effective loss of water that is thrown to the center stake being subsequently discarded. Consequently this contributes to a reduction in the factor a/c that is directly connected to increase strength.The fact that there is a sort of concrete helps to reduce voids in the mixture, which increases the durability characteristics. This condition made it possible to employ the spin technique on poles, which are directly linked to aggressive media in large urban centers.Another very attractive feature is that the centrifuge process can work with concrete with the lowest percentage of mortar and more gravel. This concrete mix directly contributes to increasing the specific modulus of elasticity, thus allowing a greater capacity to absorb the energy of the blows transferred with less deformation.Despite the great potential of land application of prefabricated spun concrete stakes there are only three factories and its limitation is the cost of transporting manufactured for the various regions, since all transportation is done by road.For its transportation is carried out exclusively by trucks, this limits the size of cuttings being produced commonly in length from 11.0 to 12.0 meters in length and smaller compositions. For use in long piles of works is resorted to amendments in the form of metal rings, concreted near the ends of the stakes, with the transfer through steel bars in CA-50 welded to the ring. Usually run in steel ASTM A-36. Later in the work these rings are welded with coated electrode.In the case of maritime stakes are very used to drowned splicing technique, which basically consists during the spin process leave one end with the armor of the apparent stake and work together two elements and make specific, with superior resistance to the prefabricated stake.This study in addition to briefly introduce the process of manufacturing, design and logistics presents a detailed study of applicat"

Jan 1, 2015

By Kyle M. Rollins

To improve our understanding of lateral resistance of pile groups, a series of lateral load tests were performed on a full-scale pile group using both static and dynamic loads. The pile group consisted of nine 0.6 m-diameter steel pipe piles driven into clay. During the static tests, the load was cycled fifteen times to evaluate the drop in lateral resistance that would occur due to repeated loading and the formation of a gap. The peak load typically decreased by about 15% from the initial cycle to the last cycle. The load carried by each pile was also measured and there was a significant drop in resistance for the piles in the trailing row relative to the leading row. The dynamic force was applied using the Statnamic loading system which produced a lateral force of 3500 kN (787 kips) in about 0.1 seconds. In two cases, dynamic loads were applied following application of 15 static load cycles. In these cases, the dynamic lateral resistance was about the same as the static resistance, likely due to gaps around the pile. In three other cases, the dynamic force was applied prior to the cyclic loading. In these cases, the dynamic resistance was 30 to 60% higher than the static resistance. Simplified analyses suggest that the difference in resistance could be attributed to damping produced by the soil surrounding the piles during the virgin loading.

Jan 1, 2002

By Vladimir M. Korolev

The field studies conducted at the experimental-production sites allowed to develop the technology of arranging drilling piles in loess subsiding grounds over 25 m deep and over 250 mm in diameter, to select optimal compositions of flush fluids, to assess the carrying capacity and field of use of the piles under test and to produce a special equipment. The dependence of the ultimate axial pressing-in load on pile driving into the non-subsiding section, its diameter and method of fulfillment, as well as the ground moisture dependence of the specific ground resistance along the piles' side surface within the limits of the subsiding section were determined. The study results allowed to reduce the length of the work piles and the number of bars in the reinforcement frames. The obtained experimental data enable to give a preliminary assessment of the piles' carrying capacity under complicated engineering-geological conditions of subsiding grounds.

Jan 1, 2002

By Michael A. McNicholas

"Deep foundations utilize the varying soil conditions to provide the most cost-effective or practical scope for a given jobsite. Once the scope has been determined and the engineering applied, the element can be installed and tested to determine if it is suitable. QA/QC programs are vital for the assurance that the element designed by the engineer has not only been properly constructed but that the design assumptions are confirmed. The two deep foundation elements referenced are drilled displacement piles (DDP) and micropiles. Each of these elements allows for large loads to be distributed deep into the subsurface geology. Having the technology and ability to monitor the tests in real-time can be beneficial to a contractor in determining if the design is adequate or if adjustments need to be made on future piles. The proper QA/QC guidelines for installation and monitoring need to be in place to ensure that an accurate interpretation can be made on the pile. This paper discusses the typical testing and the positive results that the author has encountered using the latest advances in strain analysis.KEY TERMSDrilled Displacement Piles:A deep foundation system that has the ability to shed load into the geology through shaft resistance as well as tip resistance, similar to drilled shafts. This pile element is unique in that it has a consistent pile section and thus a consistent modulus of elasticity.Micropile:A deep foundation system used in applications where the foundation lies over material not suitable for a spread footing and the ideal soil stratum is deep below the foundation. Micropiles will have two different cross-sections consisting of a cased section and an uncased section. For this reason, this pile type requires additional analysis when computing stress-strain relationships.Geokon Strain Gauges:Instrumentation such as Models 4911A-4911 Vibrating Wire Strain Gauges ( known as Sister Bars) are designed to be embedded in grout and calculate loads based on the change on grout strain over a period of time.Stress:A pile element is under a compression (axial loading) load when a force acts along its axis and is normal to the plane of the section. The corresponding stress the pile is experiencing is described as a normal stress. The stress is obtained by dividing the magnitude of the load distributed over the cross-section by the area of the pile cross-section, as shown in Eq. 1."

Jan 1, 2017

By Andrew Budek

Reinforced concrete piles are used to carry foundation loads through considerable depths of soil to provide superstructure stability under gravity loads and lateral forces. The creation of cast-in-place (or cast-in-drilled-hole, i.e., CIDH) piles begins with the auger-drilling of a hole of the appropriate depth, into which a cage of reinforcing steel is placed (the cage length is generally equal to the depth of the hole, a construction joint being used to connect the in-ground pile with the superstructure). The pile is then finished by casting with concrete, and the superstructure then appended. The superstructure may either be a column (denoting the structure a pile-column), a column and cap beam, or a footing. Typical pile-column configurations are shown in Fig. 1 (a CIDH pile used in a footing would be similar in overall configuration to Fig. 1(b), with H=0). CIDH piles are well-suited for alluvial soil profiles with a deep water table; such conditions generally allow the auguring of a clean and regular hole.

Jan 1, 2007

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 Willie M. NeSmith

In the Metropolitan Atlanta Area today, augered, cast-in-place (ACIP) piles will be considered on most projects where deep foundation support is required. ACIP piles were first used in Atlanta in the late 1960s, and application began to blossom in the mid-1980s. Current design practice for ACIP piles is addressed in another paper in this conference. This paper describes the evolution of the ACIP industry in Atlanta, and details the use of ACIP piles on major projects in the Atlanta area.

Jan 1, 2003

By Seyyed Mehdi Radeghi Mehrjou

It is important to study structures and their retrofitting techniques in order to avoid earthquake-induced seismic damage within countries that are prone to earthquakes. Todays, micro piles are employed as useful structural components for seismic behavior improvement. The present study analyzes inclined micro piles subjected to seismic loading by using the three-dimensional finite difference method (FDM). FDM assumes an idealized three-dimensional soil-micro pile model to perform logical behavior evaluation in the event of an earthquake. Linear and elastic micro piles and elastoplastic soil were employed in this study. The Mohr-Coulomb criterion was employed in the failure control of the micro piles. The micro piles were subjected to the 1978 Tubas earthquake records. The numerical results were compared to experimental data. The comparison revealed good agreement between the numerical results and experimental data. The inclined micro piles were found to sufficiently enhance soil strength under seismic loading, inducing smaller displacements than vertical micro piles. Furthermore, the soil and inclined micro piles showed salient interaction.

Sep 1, 2022

By Clarissa Aguiar, Seok hyeon Chai, Thamer Yacoub, Sina Javankhoshdel

Sheet piles are used as an excavation support for soil retention. They are interlocked systems to form a wall for earth support along with anchors to provide an extra lateral support in excavations. The earth pressure against a sheet pile structure is not unique for each soil, but rather a function of soil-structure system. Movements of the structure with respect to the soil are primary factor in developing the pressure and thus the problem becomes indeterminate. In order to model a sheet pile wall for the analysis, structural element/interface can be used for the sheet pile. However, the use of the structural element with soil model alone is insufficient to simulate this soil-structure system as it fails to capture the slip condition between the sheet pile and the retained soil. In order to capture this slip condition, an interactive element can be used between sheet pile and soil to allow slip to occur. There have been many case studies where this method was used to analyze the response of the retained soil. Numerical studies have shown a good agreement with experimental results, but this stiffness is often not a well-known parameter, due to its complexity in nature of interactive behavior between soil and sheet pile walls. Also, many case studies are carried out with twodimensional analysis of the foundation, where three-dimensional analysis may be more suitable in some practical applications. In this paper, the interactive behavior of the element between sheet pile and soil is investigated with case studies for staged excavation using sheet piles and anchors. Then, investigation of a three-dimensional model is carried out by comparing with two-dimensional analysis.

By Alessandro Bertero, Manuel Toniolo, Vincenzo Tirozzi

"The installation of foundation elements (large-diameter Bored Piles or Diaphragm Walls) for the execution of underground works to be performed through the ""Top Down"" Technique (Stations, Car Parks, Subways, Artificial Tunnels) often requires the insertion, with pinpoint accuracy, of steel or prefabricated elements within the foundation system, to provide temporary and/or permanent support to the whole structure.The future high-speed railway station of Florence Belfiore (Italy) is a perfect example; the new station will be built in the Northwest area of Florence, about two kilometers far from the existing station of Santa Maria Novella. The project envisages installation of about 500 bored piles (1200-1500-2100 mm diameter), with lengths ranging between 50 and 70 m. In the upper inner part of 250 piles, a steel pipe (weight: 15-20 tons, length: 22-25 mt.) has to be inserted with pinpoint accuracy.The “TREVI-CALATORE” system allows to install the plunge columns and adjust their position and verticality.INTRODUCTIONThe execution of underground works via the ""Top Down"" technique, train or tube underground stations, parking shafts, tunnels, often implies the need to carefully insert steel or prefabricated structures, serving as provisional/definitive pillars, into the foundation elements.The future high-speed railway station of Florence Belfiore is a perfect example; the new station will be built in the Northwest area of Florence, located about two kilometers far from the existing station of Santa Maria Novella.The new Belfiore Station is part of the new European high-speed railway network. The works related to Florence urban penetration include (figure 1):•,a 6.5 km. twin tunnel excavated via TBM/EPB, that will run beneath Florence in a north-east direction,•,passing under more than 150 buildings, many of which can be considered historic buildings, with a soil•,coverage ranging from 6 m to 20 m;•,a North portal in Rifredi area, Firenze Castello Station;•,a South portal near Campo di Marte Station (which is also the launch shaft of the TBM)•,the new Underground Station in Belfiore area."

Jan 1, 2016

By Sung-Ryul Kim, Woong-Jong Park, Juhyung Lee, Si-Hoon Lee

"A bucket foundation has been considered to be a potential foundation technology for offshore wind turbines. In this study, a series of 1-g model tests were performed to analyze the accumulated rotation of suction bucket foundations under long-term cyclic horizontal loads. The model suction buckets were made to have the embedment ratios of 0.5 and 1. The dry model ground was prepared to have two different soil densities by air-pluviation method. A horizontal cyclic load over 104 cycles was applied varying the loading amplitude. Test results showed that the accumulated rotation of the bucket foundation increased with the increase in the number of cycles and load magnitudes. Based on the model test results, a new equation was proposed to evaluate the accumulated rotation of the bucket foundations in sandy ground under long-term cyclic horizontal loads.INTRODUCTIONRecently, a bucket foundation has been considered to be a potential foundation technology for offshore wind turbines. In terms of economy, a bucket foundation has been considered to be an economical foundation type at sea beds where ground condition is clay or medium dense sand.A bucket foundation resembling a bucket is a kind of suction-installed foundation units. It is a skirted steel foundation which is open at the lower end and closed at the upper end by a lid. The embedment depth ratio (L/D) of a bucket foundation is usually less than one. Figure 1 shows an example of a bucket foundation. Offshore wind turbines are subjected to long-term cyclic loading by wind or currents. A bucket foundation is installed in soil grounds, so the long-term cyclic loading may induce the accumulation of soil deformation.In this study, the accumulated rotations of the bucket foundations in sandy ground were investigated under long term cyclic horizontal load. The number of cycles up to 104 cycles was applied varying load magnitude. The accumulated rotations of the bucket foundations in sandy ground were analyzed based on the test results."

Jan 1, 2016

By A. Flora, E. Bilotta, F. Foria, V. Nappa

"All the typical applications of deep mixing rely on the good mechanical properties of the improved columns to strengthen or stiffen the ground for a number of geotechnical applications.This paper focuses on a completely different kind of deep mixing, carried out in order to obtain columns much softer than the surrounding soil. This kind of deep mixing, named Soft Deep Mixing (SDM), is introduced as an original means to tackle seismic risk, and can be convenient when the existing structure to be protected has a historic relevance that cannot be altered with structural modifications. The idea is that properly assembled layers made of partially overlapped SDM columns, with dynamic impedance much smaller than that of the surrounding soil, will filter and reflect most of the seismic energy.The paper presents the results of some 2D parametric numerical analyses aimed to investigate the seismic performance of this innovative approach. Simplified dynamic inputs (Ricker wavelets, having only one largely predominant frequency) were adopted to better understand the effect of signal frequency. The analyses show that the effectiveness of the soft grouted isolating barrier depends on soil and SDM geometrical, physical and mechanical properties, as well as on the frequency content of the seismic input.INTRODUCTIONPassive structural systems installed at the foundation level of existing buildings are a common solution to protect them against earthquakes. However, installation procedures are expensive and not always feasible, as for instance in the case of valuable buildings. As an alternative, ground improvement techniques can be used to modify ground properties, in order to mitigate the intensity of shaking at ground level. The propagation of shear waves in the ground can be modified by introducing a layer of artificially modified material, having a dynamic impedance (defined as n =p VS, where p is the material density and VS the velocity of shear waves) very different from that of the natural soil. Both very high or very low values of the dynamic impedance of the grouted soil (nt) can be effective in reducing the overall transmitted energy, with the difference that – for a given reduction of the transmitted energy - stiff grouted layers tend to filter the low frequency components of the amplitude spectrum without modifying in a significant way the high frequency components, while soft grouted layers have the opposite effect. Then, ideally the choice of the best grouting technique should be made considering the effects of the different frequency components on the building to be protected. These effects are detrimental for the structure when they are close to its natural frequency: high frequency components result into large structural loads on massive squat structures (high natural frequency), and low frequency components may be critical for tall and flexible structures (low natural frequency). Therefore, the typical procedure of stiffening the uppermost soil layers regardless of the kind of building to be protected is not necessarily beneficial, and for the case of squat structures soft grouting should be preferred. However, this procedure has not been taken into account yet in the engineering practice, and may pose static problems at ground level (i.e. excessive static settlements)."

Jan 1, 2015

By Ross Cutts

As a public servant geotechnical engineer, I observed how costly and valuable geotechnical field explorations are to the success of every project. Often however, the field exploration is a long and complex process that is made less efficient by the difficulty of retrieving and utilizing nearby internal or external historic geotechnical datasets. As an employee of a public agency, we would often start our investigations for every project from scratch, given the difficulty of locating and utilizing historic geotechnical data. This is an ethical and technical failing of our profession. When we start subsurface explorations from scratch, not only do we often duplicate investigations, we are also likely defaulting to reapplying tradi- tional test methods that yield con- servative geotechnical parameters, resulting in overly conservative and potentially costly construction. To address this issue while working as a public servant, I started a research program with Yunfeng Zhang, Ph.D., of the University of Maryland, to build a tool that could compile internal historic geotechnical data and extract additional value from it, using machine learning. This tool was able to provide, upon request, nearby historic geotechnical data, estimated soil parameters and recommendations for geotechnical test methods best suited for a given project site. This prevented common field ex- ploration problems such as, requesting duplicate data, requesting test methods that were not applicable for the project geology, not realizing presence of karsts, missing permits for wetlands, private property and others. This tool allowed for more efficient field investigations with regards to time and money saved. There was one problem with this tool: it could only be used by internal employees of a single state's depart- ment of transportation (DOT) for which this data was compiled. I realized at that point that it would be of tremendous value to make this concept universally accessible to the geotechnical engi- neering profession. I left public service to devote time to building a platform that would host historic geotechnical data from publicly funded sources throughout the country. The tool I helped build as a public servant was the foundation of Geosetta, a nonprofit company dedicated to serving the geotechnical profession. The nonprofit structure was adopted to prevent acquisition by a for-profit company and to ensure that Geosetta remains an independent steward of our profession's valuable data. Geosetta provides a GIS (geographic information system) platform that enables users to view historic geo- technical data and extract value from it with machine learning-based predictions and visualization tools. This data is provided in an open and interchangeable format called DIGGS, which stands for Data Interchange for Geotechnical and Geoenvironmental Specialists, making it easy for users to integrate it into their workflows. Geosetta is collaborating with the American Society of Civil Engineers' Geo-Institute and other sponsors to extract public data at no cost to the agency and provide the profession with free access to the existing data and access to advanced tools through a subscription to support the nonprofit mission.

Nov 1, 2023

By Thomas J. Kennedy, Michael D. Bennett

The study of geotechnical history is well-established. Most geotechnical practitioners, teachers, and graduate students have some grasp of the origins of the field. However, this understanding often consists of a jumble of names and anecdotes. This paper discusses how a deeper comprehension of geotechnical history can benefit academia and practice alike and describes how the authors have begun a wide-ranging study of the subject. The paper reviews the dual-track methodology the authors have generated for the study, which consists of written articles about different works in geotechnical history and a database tracking how often pieces have been cited in geotechnical literature. The first technique has shed light on aspects of geotechnical history such as the connection of the Darwin family to the origins of geotechnical engineering, the St. Francis Dam failure of 1928, and the rivalry between theoreticians and practitioners in the early days of the field. The second has helped quantify subjects such as the outstanding contributions of Karl Terzaghi, the disagreements between Terzaghi and Donald Taylor, and the specialization of the field over time. The paper concludes by discussing the authors’ planned future work on geotechnical history.

Oct 1, 2022

By Adnan A. Malik, Tadashi Maejima, Jiro Kuwano, Shinya Tachibana

"The helical piling system provides solution to many geotechnical related problems due to its quick installation, higher compressive and pullout resistance, no wastage of material, workable in limited areas and reusability. However, its use as a foundation for bridges and high-rise buildings is still limited as compared to other piling methods. In the present study, the performance and load settlement behavior of screw and straight pile is investigated under cyclic compressive load in dense ground conditions. To achieve the set objectives, pile load tests were conducted in a cylindrical steel container. The model ground was compacted with dry sand at relative density of 80%. It is observed from the test results that screw and straight pile resistance reduced when the cyclic load is applied at allowable pile resistance state. The reduction in the ultimate pile capacity is more in straight pile than in screw pile. However, straight pile showed higher ultimate pile capacity than screw pile under similar pile tip diameter. The effect of helix bending deflection on load settlement behavior and ultimate pile capacity increases under cyclic loading.INTRODUCTIONScrew pile is one of the new developments in deep foundation, which is growing tremendously fast because of its quick installation technique, less noisy operation, no wastage of material and involvement of minimum manpower. Screw piles have an edge on straight pipe piles due to its high bearing capacity and uplift resistance. The installation mechanism of screw pile is different from straight pile. Torque and pressure is required to install the screw pile whereas hammering, pressure and vibration is required to install straight pile. As the installation mechanism is different between screw and straight pile, therefore, the ground disturbance that is produced during their installation is also different. The ground disturbance produced during the installation also depends upon the pile tip condition i.e. open or closed ended. Sakr, (2009) stated that the compressive capacity of screw pile in 3 to 5 times higher than driven piles having the same shaft diameter and length. The reason for this increase in pile capacity is due to helix, which is generally 2 to 2.5 times the pile shaft diameter. Larger helices can give higher end bearing capacity but it requires very powerful machinery to install in dense grounds. For instance, if large helix screw pile is installed in a dense ground then helix-bending deflection will start affecting the end bearing capacity (Yttrup and Abramsson, 2003; Malik et al. 2013 and 2015). According to Malik (2015), the equations of thin plate (Young and Budynas, 2002) with uniformly distributed load on the plate can give reasonable estimation of helix deflection due to dense ground conditions."

Jan 1, 2016

By Ben C. Gerwick

This publication is intended to document recent innovations and technologies that have the best potential for effectively improving the quality of marine foundations while reducing the cost, time and risk of construction. Marine foundations originated in Neolithic times with the Swiss Lake Dwellers who constructed pile-supported houses, safe from invading tribes. The Queen of Babylonia built the first recorded bridge in 1500 BC across the Tigris. The foundations were large flat stones laid on the river bottom. About the same time in India, builders extended their water well techniques to the construction of ?well? foundations in the beds of their rivers. These were really the first open caissons; brick walls were built up in a circular ring while divers excavated sand from the bottom, sometimes at a depth of 100 feet. The Romans extended the clay-filled cribs of the Middle East to shallow cofferdams, which they sealed by underwater concrete made with pozzolanic cement from Mt. Vesuvius.

Jan 1, 2013