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By Koichi Kobayashi

Performance-based approach to design of structures including foundations was adopted after enforcement of the revised Building Standard Law in Japan in 2000. The use of piled-raft foundation is favorable for medium-rise buildings in soft ground because of its good performance. In the design of the piled-raft foundation (Architectural Institute of JAPAN2002), vertical load is usually carried by the raft foundation, while the pile is primarily meant to control settlement of the structure. Shaft friction is expected to be larger in a nodular pile(Karkee, et.al., 1998) since it has larger surface area than a straight pile, and such piles are frequently used in piled-raft foundations. Since few structures with piled-raft foundation exist currently, the settlement characteristics of piled-raft foundation have not been fully clarified. To design piled-raft foundations with better confidence, the mechanism of vertical bearing capacity and the spatial distribution of settlement should be clarified, for which the actual behavior of the building-foundation system needs to be evaluated. This paper presents observations of settlement of a building with a piled-raft foundation at a soft ground site. The building is a steel structure covering an area an 766 m2, and consists of two-storey office block and one-storey warehouse block. The filled ground of about 5-m thickness at the ground surface is underlain by approximately 4-m thick alluvial sand layer below which lies about a 17-m thick alluvial clay layer with SPT N-value less than 2. The piles used in the piled-raft foundation are 12-m long nodular piles with nodal diameter of 500 mm (pile shaft diameter is 400 mm). The bored pre-cast piling method (Karkee, et.al., 1998) was used to install the piles. To evaluate the foundation settlement, the method of analysis of three-dimensional frame system, utilized widely in Japan, was adopted in combination with the foundation system. Basic assumptions were: (i) total ground settlement is evaluated as the sum of immediate settlement and consolidation settlement, (ii) immediate settlement is evaluated from the Mindlin?s solution in which strain dependency of shear modulus of soil is considered, (iii) settlement in clayey layers is evaluated by the one-dimensional consolidation theory, and (iv) shear spring between soil and pile shaft is represented by a hyperbolic function. The applicability of the method of analysis was verified by comparison with results of field monitoring of building settlement.

Jan 1, 2006

By Gunhild Hennum, Tewodros Tefera, Gisle Håland, Annette Jahr

"Abstract The Gudrun field is located west of Stavanger in the North Sea at water depth of 109 m. A jacket substructure was selected to support the topside and was installed in 2011. The jacket shall be able to support 16 of 0.762 m (30 in) diameter conductors and is equipped with a drilling deck to allow for pre-drilling by a jack-up rig through the jacket. In general the soil conditions below mudline comprise of a thin top layer of very loose to dense sand overlaying several layers of sandy clay, ranging in stiffness from firm to hard. Below some 30 m depth the soil consists of layers of medium dense to dense silty sand overlaying very hard sandy clay containing thick beds of sand to 100 m depth or more below mudline. The jacket is secured to the seabed by twelve 2.438 m (96 in) diameter steel pipe piles, three at each pile cluster located at the four legs of the jacket at sea floor. Different design methods were used to determine the pile penetration depth. Pile drivability was evaluated using best estimate and upper bound soil parameters. The pile driving and blow count record show that the target penetration was reached as predicted. This paper discusses the different methods used to determine the pile capacity, target penetration depth and the drivability analyses made for the Gudrun jacket piles. The soil resistance during pile driving is back-calculated from the pile installation data and compared with the prediction made.IntroductionThe Gudrun platform is located west of Stavanger in the North Sea at water depth of 109 m. A jacket substructure was selected for the Gudrun platform. The general Gudrun platform jacket configuration is to a large extent dictated by the topside layout, the requirements for support points enclosing the well slots and access for the jack-up rig. The Gudrun platform jacket is a traditional 4 legged structure with a vertical side towards the jack-up rig. At the seabed the jacket is quadratic with a base dimension of 40 by 40 metres. Figure 1 shows the Gudrun jacket during load-out from the fabrication yard to the transport barge. At the site the jacket was lifted off the barge, upended and placed on the seabed by the installation vessel. The jacket is secured to the seabed by twelve 96"" (2.438 m) diameter steel pipe piles, three at each pile cluster located at the four legs of the jacket at sea floor. The target penetration of the piles is 47 m."

Jan 1, 2014

By Lu Peiyan

A computation model of soil-pile (wall) interaction under lateral loading is presented in this paper. The model has been applied to some engineering projects, and the comparison between computation result and measured result shows good agreement, so the model is proved to be correct and practical.

Jan 1, 1991

By Larry Rayburn

In the spring of 1999, construction commenced on the new Steelers Football Stadium in downtown Pittsburgh, Pennsylvania. Richard Goettle, Inc. (RGI) was the successful bidder to install the specified augercast piles for the foundation package. Description - Pittsburgh Steelers Stadium The new stadium will house the Pittsburgh Steelers Professional Football Team. It is widely believed that if a team is provided with a modern playing facility, that a winning season will ensue (Not always the case). The new stadium location is on the north side of Pittsburgh on the Ohio River, and just downstream of the confluence of the Monongahela and Allegheny Rivers. The site is west of existing Three Rivers Stadium. The Three Rivers Stadium was built during the late sixties and housed both the Pirates Baseball and Steelers Football Teams. The Public Auditorium Authority elected to replace this outdated stadium with two new stadiums, one for each professional team. The landmark stadium was imploded in February of 2001.

Jan 1, 2001

By Zhu Tonghao

A method of calculating anti-slide pile, sheet pile, underground diaphragm and structure with anchors etc. is proposeed in the paper. The effect of the various layers of soil, anchors and bracings etc. on laterally loaded structures may be considered in the model. In the analysis the structure is divided into a series of elements. The transfer matrices of both deformation and internal force are established for each element. According to continuous condition neighbouring element should be connected. Thus the deformation and internal force of each element can be found out in conbination with boundary conditions. The method has a wider adaptability and it can be applicable to a great variety of the analysis of interaction between various structure and soil. If parameters in model are selected properly, the computed results would be in good agreement with the measured data.

Jan 1, 1991

By Shachar Magali

This article describes two new concepts regarding the CFA (Auger Cast) piles. The first one, MALI Effect, is an approach to control the casting phase, while the second one, NETA Shear, is a technique which converts the drilling rig into a geo-mechanical tool. We look upon the system of the auger and the ground as a piston inside a cylinder. When concrete (grout) is pumped into that system, an up lift force is generated (We call that force MALI Effect). That up lift force reduces the needed tension in the pull up cable. By analyzing the tension force in the cable we detect the up lift force of the concrete. That pushup force is the product of the real concrete pressure at the bottom of the auger by the area of that bottom. As the area is known, the real pressure is accurately calculated. A control loop which is based on MALI Effect is very sensitive, precise, objective, reliable and easy to be used. All the process is based on pure real physical measurements. The system has no assumptions, no comparisons, no parameters, no zeroing and no adjustments. When we penetrate into the ground like a theoretical screw, for about a meter in depth, and then brake the main cable while rotating the auger, a set of forces generates. As the auger tends to keep penetration, but the cable holds it - a tension force develops (We call that force NETA Shear). Analysis of that tension force shows that it relates to the ultimate shearing capacity of the ground.

Jan 1, 2000

By Jerry F. Parola

In current practice, pile foundation design is based on a general under-standing of pile-soil interaction during installation and superstructure-pile-soil interaction after construction. The pile design is a reflection of experience, precedent and judgment for normal piling practice of working load capacities up to approximately 100 tons with corresponding ultimate capacities up to 200 tons. For higher capacity piles, pile design is even less predictable. In particular, the feasibility of pile installation is an important design consideration that must be given the proper attention. An installation capability that is not given the required emphasis can cause unnecessary problems.

Jan 1, 1986

By Z. Q. Zhou

It is the first worke in design of pile foundation to determine the carring capacity of single pile, and a static loading on site is considered to be the lost derect and reliable way. All values P and settlements S induced can be plotted as a broken-line. Since soil is a kind of elasto-plastic and cohesive material, the increasing of settlements is generally greater than that of loads. Different value Pu nay be given by different tester on his P-S diagram, because of erroys in the test and complicated, characteristics of soil. The analytical method of exponential equation shown in this paper derives a specified solution. After using an exponential curve to regress values of loads P and corresponding settlements S from on-site test, coeficients A and B of exponential equation can be obtained. With this curve an ultimate carrying capacity of single pile can be determined. The resistant forces of pile shaft and pile tip can also be defined by the tangent of the calculated knee point, as it is called (tangent method). At last, an example is given to show how the ultimate carrying capacity of f 500mm bored pile is obtained with this method for a project in Kunming.

Jan 1, 2010

By Aditi Sharma, Sumanta Haldar

Scouring of soil is the major concern forthe various hydraulic structures built in the flowing rivers since scouring impacts the bearing capacity of foundations. Hence, consideration of scouring in the design of foundations for hydraulic structures is crucial. Pile groups in bridges are subjected to combined vertical and horizontal loading due to self-weight, live loads, vehicular impacts, wind load, earth pressure, and current. Hence, an assessment of the combined bearing capacity of pile groups subjected to scour is essential for the safety of the structure. This paper aims to analyze the bearing capacity of pile group supporting the bridge under combined loading i.e., Vertical (V) and Horizontal (H) loading subjected to local scour. Three-dimensional finite element model (3D-FEM) of a 3 x 3 pile group embedded in homogeneous sandy soil is established in Abaqus (2018). Mohr-Coulomb plasticity model is used for the soil domain. The pile group is modelled as linear elastic. Finally, V-H yield envelopes are obtained with and without scour. The potential impact of different parameters, such as angle of attack, flow velocity, depth of flow, and different pile length-to-diameter ratios (L/D) and spacing-to-diameter ratios (S/D) of pile group on V-H yield envelopes is studied.

Sep 1, 2022

By Y. El-Mossallamy

The piled raft foundation was extensive applied in the last two decades in different soil conditions e.g. in soft to stiff clay as well as in medium to dense sand and even in highly weathered rock. The piled raft is now applied not only to control the foundation settlement but also to minimize the required raft thickness to reach the most economic foundation design. An innovative application of the piled raft is its special adjustment to cases of foundations with large load eccentricities or very different loaded parts of buildings to avoid the need of settlement joints, which are especially complex below ground water table. Recently, the piled raft is applied for foundations of highway and railway bridges with special serviceability requirements regarding the allowable total and differential settlement as well as tilting. Actually numerical analyses are the mostly used design methods for piled rafts. For all day design practice a simple and modest design method is highly needed -at least in the first design stage- to check the feasibility of the piled raft on the specific project conditions. In this paper, a general overview on the recent innovative applications of piled rafts in Germany will be presented in a short overview. The results of the simple design method will be discussed and compared with the results of more enhanced numerical methods.

Jan 1, 2006

By George G. Goble

In the middle of the nineteenth century, the dynamic formula appeared as a description of pile penetration during impact driving. The simplicity of use of the formula combined with the power of the energy concepts behind the formula caused it to be quickly accepted and integrated into practice. Dynamic formula had been in use for 100 years when the Wave Equation computer programs first appeared. With that long experience it is not surprising that the formula continued to be used and were only slowly abandoned. The Wave Equation offers many advantages over the various formula but it does not offer a clear sense of physical understanding of pile driving that is available with the formula. Large amounts of numbers are generated but often it is difficult or impossible to gain a physical understanding of the results or a feeling for the importance of the various parameters. The question that the Wave Equation user has is, "What will happen if I use a larger drive cap (or change any other item of equipment)?" In this paper, I will attempt to explain pile driving using elementary wave propagation theory. However, the presentation will not depend on any higher mathematics. With the use of wave mechanics, it is possible to explain driving characteristics that cannot be handled with the energy formula.

Jan 1, 1995

By Vidyaranya Bandi, Madhav Madhira, Kota Vijay Kiran

"Using hyperbolic relationships for the non-linear responses of shaft and base resistances, a method is proposed for estimating initial shaft and base stiffnesses and ultimate shaft and base resistances of a pile from pile load test results. An iterative procedure is used to arrive at the values of shaft-soil and base stiffnesses and the ultimate shaft and base resistances. The method is applied to load - displacement data available from pile load test results to illustrate its efficacy.INTRODUCTIONA pile foundation is the most effective and economical solution in transferring large vertical loads to deeper depths. As the pile is subjected to axial load, the soil mass surrounding the pile is vital in providing vertical support for the pile. The nature of pile–soil interaction is three dimensional and to complicate the problem further, response of soil is nonlinear. Finding a closed form solution to such problem is extremely difficult. Several methods were developed to study and predict the response of the composite pile–soil system. Faruque and Desai (1982) implemented both numerical and geometric non-linearities in their three dimensional finite element model. Rajashree and Sitharam (2001) developed a nonlinear finite element model of batter piles under lateral loading using a hyperbolic relation for static load condition and modified hyperbolic relation, including degradation and gap for cyclic load condition.The ultimate capacity of the pile is estimated considering the strengths and unit weights of soil layers with depth, overburden pressure and other relevant parameters. The estimated capacities always need to be validated by conducting initial maintained load test. The estimated capacity may differ with the actual at site since the values of strength, stiffness, interface resistance between pile and soil, lateral earth pressure coefficient with depth and soil stratification, etc., differ from the design parameters considered for estimating the ultimate capacity of pile. The estimation of axial capacity of piles involves considerable uncertainties in selection of appropriate design parameters and the design rules are not always consistent with the installation procedures/processes involved."

Jan 1, 2017

By Osama Safaqah

The new Cooper River Bridge will replace two existing bridges along U.S. Highway 17. The cable-stayed bridge will be one of the largest in the U.S and will connect the City of Charleston and the town of Mount Pleasant, South Carolina. The 1,546-foot long main span over Cooper River is supported by two diamond-shaped towers and will allow for 1000-foot wide navigation channel. The Charleston high-level approach is approximately 4351-foot long and will provide 250-foot wide navigation channel over Town Creek, while the Mount Pleasant high-level approach is 2090-foot long. Due to the high seismicity in the region, potential vessel impact, and hurricanes, large lateral loads are expected. Among various types of foundations, 10-foot diameter drilled shafts were selected for their high capacity against lateral loading. The shafts are founded on a stiff to very stiff lightly cemented calcareous sandy clay or sandy silt layer, called Cooper Marl, which underlies coastal sediments of interbedded clays and sands. The main towers will be supported on a group of 11 shafts and protected from ship collision by a rock island. The High Level Approach piers will be supported on a pair of 2 shafts. The shaft tip elevation is up to 230 feet below water line. An elaborate geotechnical investigation has been conducted on the site including a load test program on full-scale shafts under axial and lateral loads. The results of the tests were used to calibrate the lateral and axial soil resistance. The objective of this paper is to present the different aspects of the bridge foundation design.

Jan 1, 2005

By Dongwook Kim

Recently, load and resistance factor design (LRFD) is gradually being adopted internationally in geotechnical design due to the advantages of LRFD over the existing allowable stress design (ASD). LRFD is a more advanced design method compared to the ASD because resistance factor is calibrated based on the reliability analysis for a given target reliability index. Target reliability index changes with the importance of the structure. Typically, target reliability index of offshore foundation is less than those of onshore. The widely-used Imperial College Pile (ICP) design method is used for the calculation of pullout capacity of driven piles. The uncertainties regarding pullout capacities of driven piles are assessed using the statistical data reported in the literature. The first-order reliability method (FORM) is used to calibrate resistance factors for the pullout ultimate limit states of the driven piles for three different levels (2.5, 3.0, and 3.5) of target reliability index. The load factors used in this paper are the ones proposed in the AASHTO LRFD bridge design specifications.

Jan 1, 2010

By John C. Niedzielski

The existing US-70 Bridge over the Gila River at Bylas, Arizona is planned to be replaced due to its current poor condition. The replacement bridge is planned to be a 15-span, 1,904-foot (580 meter) long bridge, the third-longest bridge in the state highway system. Within the Gila River floodplain, granular alluvial soil is underlain by cohesive lacustrine soil; bedrock was expected due to nearby terrain but not encountered within the geotechnical exploration depth of 166.5 feet (51 meters) or less. Based on the anticipated loading conditions, design scour depths and the soil conditions, the full structural loads are carried by large diameter drilled shafts; therefore accurately determining the axial capacity of the proposed drilled shafts has important practical and safety implications. The conventional methods for axial capacity determination may be overly conservative to use for design in the site?s layered granular and hard clay soils. An Osterberg cell load test was performed to obtain detailed information on the load transfer from the drilled shaft in side friction and base resistance to allow optimization of the bridge foundation design. The full-scale field test played a significant role in the design of the project?s deep foundations, notably, by incorporating the specific subsoil properties and consequently, an exact prediction of the load-settlement behavior under loading. This paper provides the results of the geotechnical site investigations, drilled shaft load testing procedures, and shaft load distribution from the load test results. Comparisons were developed between predicted axial capacities of drilled shafts using several design methodologies and the axial capacity measured from static load testing. The load test results showed that underestimation of the axial capacity is evident using conventional methodologies. The exact prediction of the load-settlement behavior under loading combined with a site-specific design approach, resulted in a substantial reduction of foundation costs due to reduced drilled shaft dimensions.

By J. C. W. M. de Wit

An excavation, within which a tunnel is sunk as a part of the Centraal Station underground station (platform section) of the Noord/Zuidlijn ('North/South Line'), is to be created beneath the Amsterdam Centraal ('Amsterdam Central') station. The section beneath Amsterdam Centraal Station is characterised by the application of a particular technology in the form of, inter alia, the so-called 'sandwich wall'. This is a composite wall consisting of two rows of Tubex piles with a body of jetgrout columns in-between. This wall acts both as an excavation support wall and also provides vertical bearing. The installation of the wall, including both Tubex piles and jetgrout columns, within these specific conditions (limited height, sensitive historical building), within the design requirements set in terms of construction tolerance and water and soil retention, may be regarded as being a pioneering achievement. The environmental constraints are that the trains should continue to run, the inconvenience to passengers should be kept to a minimum and the historic station should not suffer any damage. Because of the complexity of the working conditions, the project is being overseen by a steering group of experts in the specified construction processes. In order to manage the project risks, jet grouting trials were initially carried out, in order to highlight and control execution problems; the practicability of the design is then tested. Work commenced on the sandwich wall in 2003, when the wooden piles were extracted at the locations where the sandwich wall was to be constructed; in 2004, the steel Tubex piles for the southern wall sections were installed. From May 2005, the construction of the sandwich wall got under way; in addition to the described process supervision, an extensive measuring programme was established, so that the process could be adjusted as necessary and the quality of the finished product determined. This applied to both individual columns and for the end product, the sandwich wall. The measurement results were processed for each column, interpreted and the effect on the work still to be conducted was assessed for each future column. Preventative and corrective measures were, if necessary, taken in order to control or counteract the measured defect. In addition to the process-oriented and qualitative measurements, various independent measurement systems at the station building served as a further control in order to prevent damage to the building.

Jan 1, 2006

By F. Z. Suo

Baoahan Iron and Steel Complex is situated at lower beaches of the Yangtze River. The subsoils 50~70 M below the surface is a deposite of Yangtze River delta, consisting mainly of weak silty clay and loam, with low soil bearing capacity. Consequently, to build on such a weak soil a grant iron and steel integrated works weak soil improvement at the Complex, pile foundation is the effective type. It is estimated that at the first stage of Baoshan project 60,000 piles have been driven, of which 60% are steel pipe piles and 40% reinforced concrete piles. To provide reliable basis for pile foundation design, on-site loading tests were carried out for long reinforced concrete piles 27,45 60 M in length ,with strain gauges on the chief reinforcement of pile shaft and strain rod on pile tip. Based on loading tests, the paper discusses and analyses some issues, including determination of load transfer mechanism distribution of frictional resistance. Tests show that as far as long friction piles in soft clay are concerned, regardless of the properties of pile tip's bearing stratum, loads are mainly carried by shaft frictional resistance which it is effective to determine pile capacity in terms of P ~ S relationship.

Jan 1, 2010

By Theodore R. Maynard

The history of foundation engineering in Chicago is a tale of innovation, made necessary in order to keep pace with structural technology which allowed taller buildings with heavier bearing loads, to accommodate a non-conducive geologic setting. The geology as it relates to foundation construction and underground construction in general is briefly described. A chronology of important events from the birth of Chicago to the present is presented. The impact of various construction techniques which were either initiated or refined to allow the growth of Chicago are discussed. Introduction The growth of Chicago resulting in today's high-rise high-density population center can be looked upon as a history of modern underground construction. The two major reasons which explain this are 1) It grew up during a period of rapid development in the Industrial Revolution and 2) Its natural geological setting needed a great deal of innovation for continuing growth.

Jan 1, 1991

By Priyadharshini M. R., Premalatha K

"Abstract With the development in the construction of heavily loaded structures, the necessity of pile foundations has increased. For the transfer of heavy loads, it is mandatory that the piles need to be socketed in the underlying rock strata. The load transfer in bored rock socketed piles is by end resistance or the combination of shaft and end resistance which in turn depends on the length of the rock socket. The determination of socketing length of the pile at present is mostly based on a few factors which affect the pile load transfer mechanism. The effect of all the possible factors involved, need to be studied in proposing guidelines for the design of rock socketing length of the pile. Analyses are carried out using finite element analysis software (PLAXIS 3D Foundation) to understand the influence of the thickness of overlying strata for different socket lengths of piles in weak rock. From the load settlement curves, the influence of the overlying soil on the rock socket length isobserved and an effective rock socket length is proposed.IntroductionThe determination of socketing length of the pile at present is mostly based on a few factors affecting the pile load transfer mechanism, which sometimes give a better design and sometimes an uneconomical design. Too much socketing length results in more construction time and higher costs. Therefore, the effect of all possible factors involved need to be studied in proposing guidelinesfor the design of t h e r o c k socket length of the pile.The factors that affect the termination criteria of the rock socketed pile are the capacity requirement, thickness and properties of the overlying soil, characteristics of the founding strata, drilling tools used, roughness of the rock socket and nature of loading.A comprehensive study was performed to understand all the above mentioned factors in different types of rocks. In this paper discussion is made on the settlement results, specifically the influence of overlying sand of different densities above a weak rock. The influence of stress developed is not discussed, keeping in mind the size of the paper under study."

Jan 1, 2014

By W. J. Kingwell

My comments and questions are addressed to Mr. Troughton. It seems to me that the tests were very well tailored to determine long term effects on performance of bearing piles as groundwater pressures rise in the London Basin. This rise is being simulated by means of a groundwater recharge system but it would be informative to have further details of the controls of conditions simulated. Ideally the porewater pressure in Standpipes 1, 2 and 3 should be the same throughout the test. Under test conditions are there not practical dif­ficulties? Recharge Well C2 is a lesser dis­tance from the pile than the other wells. Was the rate of recharge to C2 regulated to a lesser rate than the other three? In my experience the rate of acceptance usually varies from well to well. Under a common feed pressure were mea­sures taken to compensate for this? Since the problem does not only affect London, but also Liverpool, Nottingham, Birmingham and to a lesser extent, Manchester, I question whether an ideal procedure is being used. It is well known that rates of acceptance decrease with time and often recharge wells need to be flushed out at regular intervals. Other pro­cedures may need to be adopted to accurately simulate the effect of groundwater rise, if tests of longer duration are to be considered.

Jan 1, 1991