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By Bill Zietlow

A micropile and soil nail underpinning system was installed to support a building immediately adjacent to a 25-ft deep excavation in downtown Salt Lake City, Utah. Both the building and the underpinning were instrumented to monitor deflections, rotation and crack growth. The underpinned structure consisted of a two story concrete masonry unit (CMU) building founded on shallow spread footings attached to a concrete high-rise building on spread footing two floors below grade. The face of the excavation was 10 in. in front of the underpinned building foundation wall. The underpinning system consisted of small diameter hollow bar micropiles installed with injection grouting techniques below the bottom of the excavation and attached to the underpinned structure by a concrete pile cap doweled into the existing footing. The lateral loads imposed by the soil under the underpinned structure were designed to be supported by the soil nail wall installed through the micropiles during excavation. The settlement monitoring instruments consisted of crack gages, optical survey prisms, high sensitivity vibrating wire water levels and biaxial vibrating wire tilt meters. They recorded maximum movements of approximately 0.1 in. of settlement, 0.05 deg. rotation (top of wall rotating away from excavation) and up to 0.08 in. of crack opening during the excavation until one month after the soil nails and shotcrete facing were completely installed. This movement was well within both the estimated settlement and the estimated settlement tolerance of the underpinned structure.

Jan 1, 2008

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 A. A. Gupte

Auger piling system which was developed in the United States in the 1940's is gaining acceptance in many parts of the world. Although primarily used to support foundations, the system is very useful for many other applications such as soil anchors, temporary and permanent earth retention systems, restricted headroom piling and underpinning of existing foundations. In this paper, review of current construction design techniques for the Auger piling system for earth retention and underpinning of structures is presented.

Jan 1, 1989

By Thomas M. Caruso

Construction of a new ship dock at a major Philadelphia area refinery required geotechnical design and field consultation. The new dock, which consists of a system of mooring dolphins and platforms, will be capable of docking the Stena V-MAX Oil Tanker (V-MAX). The 1100 ft long V-MAX is currently the largest tanker to travel the Delaware River and will induce significant lateral loads on the new ship dock. Lateral loads induced on the dock will be resisted by over 200 pipe piles installed on a batter. The piles used for support of the dock included 20 and 30 in. diameter reinforced, concrete filled pipe piles. Complete construction of each pile included driving of the pile to the design ultimate capacity, flushing the pipe pile casing clean of overburden materials followed by drilling rock sockets into the underlying Wissahickon Formation. Variations in depth to bedrock, rock quality and degree of weathering and presence of very hard quartzite lenses created a complex geologic environment that presented challenges for the pile/rock socket design and installation. The design of the pile system, installation methods, QA/QC and testing (Pile Dynamic Analysis), as well as the challenges that were encountered through the duration of the project are presented and discussed.

Jan 1, 2008

By A. Partos

It was decided to build a fourteen-storied office building over a six-storied garage and a four-storied office building. The high vertical and horizontal loads required foundations on rock approximately 18m below street level. Drilled piers (caissons) were selected. Eight caissons (1.98m diameter) were installed through the six-storied garage and four caissons from a temporary deck at the location of a former two-storied building. Excavations were done by the slurry method. Proof testing of rock was done before construction by test borings and during construction with a core barrel of small diameter. Quality control measures included telecommunications between ground crews and the equipment operator on the garage roof; records of field observations and testing of bentonite slurry and rock; and a continuous evaluation of all information. Instruments were installed in one caisson to monitor load distributions and curing of concrete.

Jan 1, 2010

By J. K. Mitchell

Soil improvement is examined within the context of the characteristics of different soil types, the types of ground improvement techniques that can be used to improve them, and the level of improvements that might be achieved. Several case histories are described to show how the particular soil and foundation characteristics influence the choice and success of different ground improvement techniques. Although the basic methods for soil improvement have been known for many centuries, there have been significant recent advances in the technology for their use. Time effects following the densification of cohesionless soils may lead to significant improvements in strength and stiffness. Unanticipated chemical reactions may follow stabilization using admixtures when soils for which there has been little prior experience are encountered. In some cases foundations that combine features of both ground improvement and deep foundation systems may provide good performance at reasonable cost.

Jan 1, 2010

By Jeffrey R. Hill

This paper discusses the use of micropiles for the rehabilitation of the following two structures: the Milwaukee Auditorium Theatre, in Milwaukee, Wisconsin, and the Cupples Ballpark Lofts, in St. Louis, Missouri. The paper focuses on the similarities and differences of the remediation techniques used for each structure. The discussion highlights the method of attaching the micropiles to each respective structure. Generally the paper discusses the micropile installation at each project with supporting photos, figures and data. Load testing at each project is also discussed, including the comparison of load test results for each project. The paper will focus on the load testing program at the Milwaukee Auditorium Theatre where high capacity micropiles were designed and tested as friction piles founded in stiff clays and end bearing micropiles in dolomitic limestone. The results of the test were used to determine if the micropiles on the project would be installed as end bearing or friction bearing elements. Strain gauges were used in addition to conventional deflection vs. load data for the Milwaukee Auditorium Theatre project. Other aspects of the paper will include the differences in design methodology for end bearing micropiles in massive dolomitic limestone vs. design in softer, weathered limestone.

Jan 1, 2008

? Hollow Stem Auger ? Drill Bits ? Leads/Torque Arm ? Hydraulic Gearbox ? Hydraulic Power Unit ? Grout Pump ? Crawler Crane

Jan 1, 1998

By Gopal Ranjan

An insitu prtotype study on precast driven spliced piles in soft marine clay deposit has been carried out to study negative drag. The drag is generated by loading the ambient clay. For reduction in negative skin friction, in addition to use of bitumen layer on piles, the ambient clay is transformed into composite mass of low compressibility by utlizing different ground imporvment techniques e.g. plain granular piles, mini grouted piles and self setting soil slurry piles. Adoption of these techniques resulted in significant reduction in settlement of ambient ground and consequently the negative drag on piles. On the basis of the study it has been established that these techniques improve ground condition resulting in lowering of down drag/negative friction.

Jan 1, 1996

By G. L. Sivakumar Babu, P. Chaithra

"Raft foundations which are used against differential settlements and for carrying heavy loads can still be subjected to excessive settlements even if it is safe against bearing capacity consideration. Providing additional piles under the raft can reduce such settlements to acceptable values. In addition to settlements, the piles also relieve the raft a part of the total load and thus the bearing capacity of the Combined piled raft foundation (CPRF) is improved. Parametric study of response of piled raft foundation has been conducted and the results have been presented. The study is conducted using finite element based software, PLAXIS 2D. The main objective of the paper is to evaluate the parameters that affect the performance of piled raft for an economical and effective design. It has been shown that piled rafts are an economical solution in foundation design compared to raft foundation, for the soil conditions considered in the paper.1. INTRODUCTIONThe aim during the design and construction process of high-rise building foundations in urban areas is to ensure the lifelong safety and serviceability of the new and existing buildings in the neighborhood. In order to realize this aim in a cost-optimized manner, the combined pile raft foundation (CPRF) was developed (Katzenbach et al., 2005). For the foundation of high rise buildings with good subsoil, the simplest structure considered is a raft. But when the subsoil near the ground surface has low load-bearing capacity, high-rise structures are often rested on piled foundations.A piled raft and pile group serves similar purposes, but there are essential differences between them. A pile group is a set of piles that have a pile cap. The piles would be designed to share the pile load at ultimate state. The pile cap would be designed to link the piles together but the contribution of the pile cap to bearing capacity will not be included in the design. On the other hand, a piled raft is a foundation, wherein piles are provided along with the raft so that the total load acting is shared partly by the raft and partly by piles, rather than being dominated by the piles (as in a pile group). Piled raft foundations utilize pile support for control of settlements with piles providing most of the stiffness at serviceability loads, and the raft element providing additional capacity at ultimate loading (Poulos, et al., 2011). Therefore, piles are included in a foundation for two main design purposes: to provide adequate bearing capacity and to bring down the settlements to an acceptable level."

Jan 1, 2015

By Richard Schmidt, Lijun Deng, Mohamed Abdelaziz, Weidong Li

Helical piles are widely used as a foundation supporting a variety of different structures. Understanding the axial behaviour of helical piles is required to confirm the engineering design. Helical pile research is often conducted in the field, but this method can be prohibitively expensive in some cases. Geotechnical centrifuge modeling offers an alternative method for the helical pile research and practice. A series of axial load tests of helical piles installed into cohesive soils were conducted on the geotechnical centrifuge at the University of Alberta. The objective was to investigate the effects of inter-helix spacing and soil strength on the axial behaviour of helical piles. Four types of aluminum model helical piles including one single-helix pile and three double-helix piles with various inter-helix spacing ratios were tested. Both compressive and tensile loading tests were conducted. All model piles were instrumented with multiple strain gauge stations. The clay had an undrained shear strength of approximately 50 kPa and 120 kPa. The test results indicate that there is a transitional failure mode between the two widely recognized failure modes, i.e., individual plate bearing and cylindrical shearing. The shaft adhesion was significantly reduced by the helix. Axial capacities were comparable to the field test results.

By F. M. Abdrabbo

Flight auger bored piles are formed by screwing a continuous flight auger into the ground, and pumping cement/sand grout or concrete down the hollow stem of the auger as its withdrawn. The auger is driven at the top by hydraulic or electrical motor and is guided by a vertical crane leader. Loading tests on concrete piles are described. The stability plot method is used to drive the shaft friction and the end bearing load components of the pile capacity. This paper outlines features of crucial construction factors that affect the geotechnical capacity of this type of piles. These factors include, vertical speed of auger during boring, grout factor, grout pressure, number of reborings, type of material, and slump of concrete used to form the piles. Two of these factors are highlighted in this paper. It was found that, shaft resistance is independent of grout factor, whilst point resistance increases as grout factor increases. Nevertheless the engineer should decide the safe pile load associated with the most economical grout factor. High vertical speed of auger during boring of piles may cause disaster for the adjacent buildings, due to soil decompression.

Jan 1, 1993

By Ben C. Gerwick

Large diameter steel tubular piles installed vertically or on a slight rake, offer many advantages as the foundations of major overwater bridge in regions of high seismicity. By proper selection of diameter and wall thickness, an optimum balance between stiffness and strength can be achieved. Under strong seismic motion, the piles will deflect and bend so as to reduce the acceleration forces transmitted to the superstructure, while still limiting drift. A major advantage of this concept is that the mass of the footing block is significantly reduced from that of the conventional pier. The design of the footing block requires great care in order to transfer the high shears and moments. Where the soils consist of significant depths of sediments, the kinematic interaction of soils, piles and structures must be considered. Moments will be a maximum just under the footing block. Filling the top portion of the pile with concrete will prevent local buckling and assure ductile behavior even under overload. Typically the piles will be long, with most or all of their support furnished by friction and will require the use of very large pile hammers to achieve the required capacities. Where the piles are founded on rock or in hardpan, sockets will be drilled and filled with reinforced concrete. For these piles, high moments can occur both at the head and just below the rock surface, so the concrete infill should extend the full length. This paper describes the use of tubular piles driven through the deep silty sands of the Jamuna River, Bangladesh, and also where socketed into the near-surface rock for the mail pylon pier of the new San Francisco-Oakland East Bay Bridge in California.

Jan 1, 2013

By Matthew C. Pierson

Due to space limitations for transportation projects, many times sound walls must be constructed above mechanically stabilized earth (MSE) walls. These sound walls must resist lateral loads from wind or impact and must therefore be constructed on drilled shafts passing through the reinforced fill for the MSE Wall. Current design methods for the drilled shafts are believed to be overly conservative. Full scale lateral load testing of three foot diameter shafts contained within and solely supported by a 20 foot tall MSE block wall was conducted and the lateral capacity was evaluated. Shafts were tested individually and as a group. The data collected from full scale testing was then used to calibrate numerical models. This paper contains a discussion of how the facing type and stiffness affects the behavior of the numerical model as well as selected comparisons between the actual test data and selected model simulation results.

Jan 1, 2009

By Robert J. Carle

This paper reviews a variety of highway structures which have been built using steel sheet piling as the permanent structural elements of bridge piers, abutments and wingwalls. Those structures built over the past 20 years in Europe include major highway bridges over railroads, highways and waterways in both urban and rural locations. Most highway structures built in the United States using steel sheet piling have been limited to secondary roads in rural locations. The main thrust of this paper is the presentation of various design concepts for highway structures which utilize steel sheet piling. The main purpose is to challenge the profession to move forward from this conceptual presentation and to develop the details necessary to provide safe, cost-effective structures which go well beyond the scope of those being built in the United States today.

Jan 1, 1989

By Ali Porbaha

In today's fast-track construction environment, owners are searching for non-conventional technologies to build their projects faster and safer while maintaining traffic flow during construction. To that end designers and contractors are providing solutions that incorporate many unique features to expedite construction processes. In addition to timely delivery of the finished highway products, there is an increasing interest in making the initial investment in applying innovative technologies and thereby minimizing costly maintenance of highway projects. Accordingly, the aim of this paper (along with the accompanying paper) is to examine innovative technologies, developed mostly in Europe, that accelerate construction of highway, runway and railway embankment foundations. For each technology, a basic concept, installation technique(s), and design considerations are discussed, along with the case history of a real-world project. The Geotextile Encased Columns (GEC), AuGeo, and Continuous Flight Auger (CFA) are presented in Part I. Deep Mixing (DM), Cut-Mix-Injection (FMI), Mass stabilization, and Combined soil Stabilization with Vertical columns (CSV) technologies are discussed in Part II.

Jan 1, 2002

By M. Y. Xia

In this paper, based on the Theological tests of the interface between clay and concrete, an interface Theological model is proposed and is used in the finite element analysis which takes soil as viscoelastic mass and Theological effect of the interface between diaphram wall and ground into consideration. Its results are compared with those without an interface element, without considering the relative creep displacement. Close attention is paid to the variation of wall with time under the condition of various interface shear stiffness and viscous sliding coefficient, and their effects on the wall bending moment are primarily verified in the paper. The change of wall bending moment with time, trench heave and wall displacement in different excavation depth, bracing position, parameters for soil are also studied.

Jan 1, 2010

By Serge Borel

An efficient design method is proposed for "piled-footing" and "piled-raft" foundation under lateral loads. It combines the methods used for the displacement design of shallow and deep foundations and takes into account the interactions between the piles and the cap or raft. This method has been applied to previous full-scale tests carried out in the United States. Two groups of six instrumented driven piles were laterally loaded several times: first with the concrete pile cap in direct contact with the soil, and then, after a thin layer of soil had been removed beneath the cap. The proposed method models well the real behavior of piled-raft foundations. It highlights the positive effect of the cap in contact with the soil, which reduces significantly the displacements and the maximum pile bending moments. These are divided by two for the analyzed case histories.

Jan 1, 2002

By J. W. Slatter

Cast in situ screw piling techniques (both displacement and non displacement) have seen considerable growth in recent years due to competitive production rates, low noise and vibration free installation. However the discussion on the mechanics of auger installation, which has implications on the installation effects and installation forces of screw piling augers, has been almost exclusively targeted towards non displacement techniques and in particular continuous flight augers (CFA). This paper discusses the historical development of the understanding of screw piling auger mechanics in sands and presents a new theoretical model to predict the soil transport and displacement characteristics of both displacement and non displacement augers with variable geometry.

Jan 1, 2000

By Prof. Dr. -Ing. habil. Sascha Henke, Johannes Beck

The growth of Building Information Modeling (BIM) during recent years opens possibilities for integrating new digitally driven design approaches. While parametric design and algorithmic design slowly gains popularity in numerous ACE-applications, e.g. bridge design, it is rarely used by geotechnical professionals. This article presents an approach for implementation of parametric design in the BIM-based geotechnical design process. The methodology is applied to pile design and enables a real time design analysis according to DIN EN 1997-1 and EA-Pfähle 2012 considering boundary conditions such as pile position and layout, pile geometry, soil stratification and soil properties. By using intelligent attributes and scripts to control, calculate and assign them, the design analysis is directly executed in the BIM-software environment, in this case Autodesk Revit with Dynamo. This BIM integrated design approach allows multi-criteria evaluations of pile designs using aspects such as costs, environmental impact or constructability in addition to the commonly examined structural analysis criteria. As the proposed models are fully parametric, generative optimization algorithms can be applied to identify the ideal design for the entirety and each of the piles. Finally, the potential and limits of this methodology with respect to modeling, analysis, simulation and optimization are discussed.

May 1, 2022