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By Bengt H. Fellenius

Session 2, Deep Foundation without Soil Excavation, has attracted no fewer than 22 papers dealing with subjects from soil improvement by grouting, injection, and deep mixing techniques through vibroflotation and special piles, including aspects pertaining to conventional driven and bored piles. In the short time available, it is not possible to both do justice to the papers and provide a critical review of the state-of-the-art. Instead, to meet the objective of making the next half hour worthwhile to the audience, I have chosen to comment on a few special points brought forward in the papers and thereafter to discuss more in detail a couple of aspects I have deemed to be of general interest. Four papers deal with jet-grouting, injection, and deep mixing techniques: DOMSKI, J. J. Reinforcement of subsoil under the foundations of historical buildings in Cracow using deep injection technique. RESTELLI, A. B, BERTERO, M., and LODIGIANI, E. Deep mixing technology to improve the bearing capacity of a very soft clayey soil under an earth embankment.

Jan 1, 1994

By Upendra L. Karna

The pile capacity gain with time evaluated and implemented for the construction of the Route 21 Viaduct in Newark, NJ, U.S.A is discussed in this paper. The project consisted of the replacement of more than 3.2 km of viaduct and ramps. The project site consists of thick residual materials deposited by the Wisconsin Glacier over sedimentary rocks. The upper portion is glacial-lacustrine deposit underlain by marginal morainic till and stratified drift. Subsurface investigations identified significant variations in layer thickness and grain size consistency. The site was characterized into 4 Soil types, based on subsurface soil behavior. Closed end 600 mm and 450 mm diameter driven pipe piles were used for the foundation. Loading tests conducted during an advanced construction contract, established that a significant soil set-up could be expected. For the first construction contract, a pilot loading test program consisting of 112 dynamic loading tests and 77 re-strikes (at 2 to 4 weeks) using the PDA (Pile Driving Analyzer) with CAPWAP (Case Pile Wave Analyses Program) was conducted to establish the soil set-up behavior. Nine (9) quick static loading tests were conducted to substantiate the long-term pile capacity. Based on the loading test results, average set-up factors were established and utilized for developing production pile driving criteria. Bearing resistance with depth was analyzed and reviewed. The set-up factors varied significantly, ranging from 1.05 to 1.89, and averaged about 1.30. Conclusions are derived. Set-up factors behavior for each soil type plotted by linear regression are presented and discussed. An appropriate set-up with time relationship for a glacial soil is suggested.

Jan 1, 2006

By Raymond J. Castelli

The paper provides a general overview of the numerous types of earth retaining systems currently available, and organizes these various systems by several classification methods. These classifications can be used as a guide in identifying the appropriate type wall or walls for any specific project application. As a further aid in sorting through the numerous wall alternatives for a specific design or construction project application, the paper suggests a systematic approach for wall selection, and presents helpful charts summarizing the general advantages and disadvantages, and typical limitations for the currently available wall systems.

Jan 1, 2003

By Peter Faust

The foundations for the new South Viaduct Bridge in San Francisco were extremely challenging due to the requirement for very large and deep piles installed adjacent to historic structures. Drilled shafts up to 12? foot in diameter were constructed to a maximum depth of 200? feet in alluvial soils and Franciscan Bedrock using an oscillator system for the installation of the permanent steel casing. This paper provides an overview of the construction techniques, the equipment, and the challenges associated with constructing 12? foot diameter shafts on this very complex project in one of the nation?s nicest landscape setting.

Jan 1, 2011

By N. Charue

An international prediction event was carried out within the framework of a 30-pile testing program organized in a sandy soil in Belgium (Limelette). That program called upon sev­eral testing methods: static load tests, Statnamic testing, and dynamic testing. This paper provides a summary of received predictions and results obtained from the static pile load tests, which were carried up to failure of the instrumented piles. The comparison between predictions is made using load-settlement curves with reference to the results of the static load tests. The predictions are based on a geotechnical approach using an extensive soil investigation program and a dynamic approach using the dynamic load test data.

Jan 1, 2002

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 Richard J. Hartman

Current design practice is to select steel sheet piling sections using sufficient section modulus and yield strength to resist the calculated bending moment. Thus, section modulus is the only property of the sheet pile cross section used in the selection process. Full scale laboratory testing documented that section modulus alone is insufficient to predict the strength of sheet piling. During testing, sheet pile sections with equivalent section modulus exhibited as much as 75 percent difference in load resisting capacity. Analytical study following the testing established that, in addition to the traditional longitudinal (vertical) stress in sheet piling, transverse (horizontal) stresses are also present. Transverse stresses reduce the ability of the sheet piling to function in the intended manner. It was found that transverse stresses result from the pressure applied by soil and water and that the capacity of the sheet piling diminishes with increased pressure. All sheet piling is subject to this behavior. This paper describes the testing and the results and establishes that a problem exists. A two dimensional procedure is described that assists in evaluating transverse stresses and their effect on sheet pile capacity. A method of creating design aids for use by engineers is illustrated.

Jan 1, 2006

By Alexander Filotti, Stanley Merjan

"Abstract. The paper shows the benefits and accomplishments of this relatively new but established product on the pile foundations market in the United States. The first part of the paper describes general aspects of the design, construction, and geotechnical capacity (designed and in situ) of Tapertube piles. The qualities resulting from the design and manufacturing of the Tapertube pile will be presented first.The second part of the paper describes the installation of Tapertube piles for an addition to Terminal One at JFK International Airport and The Edge development. A carbon print analysis for both projects is developed using the EFFC-DFI carbon print calculator. For the JFK project the benefits of using BIM in redesigning the project for Tapertube piles are explored.General description.The tapertube pile consists of a tapered tubular bottom section attached to a conventional pipe extension. The 50 ksi steel for the taper is mechanically folded into a polygonal cross-section (usually 12-sided) with a longitudinal welded seam. The tapers are fabricated in many sizes with bottom diameters varying from 8 to 14 inches, top diameters from 12 to 20 inches, lengths from 10 to 35 feet, and steel thicknesses from 3/16 to 1/2 inch. A conical steel shoe or a flat plate is welded to the bottom of the taper and the top of the taper is circularized to match the outside diameter of the pipe extension. The inclination of the tapers is generally between 1.5% and 2.5%.The pipe extension is fully butt welded to the taper and has the necessary length for the pile to develop the requisite capacity. Concrete fill for the piles is generally 4,000 p.s.i. or more. Typically the piles are shopassembled and shipped to jobsites in lengths to 80 feet."

Jan 1, 2014

By Khamis Y. Haramy

Quality assurance and quality control of drilled shafts has become a concern due to difficulties in accurately locating construction anomalies and determining load bearing capacity of defected drilled shafts. Various non-destructive evaluation techniques have been developed to estimate the integrity of the concrete in drilled shafts. While these techniques have been widely accepted, variables and unknowns can affect the measurement results. Results are typically difficult to interpret, leading to unnecessary construction delays and possible litigation over shaft integrity. In addition, influences of surrounding ground materials, stress states under different load conditions, and crack and residual stress development during concrete curing further complicate determination of shaft performance. This paper focuses on the evaluation of load bearing capacity of defected drilled shafts under various conditions by numerical analysis and modeling.

Jan 1, 2007

By Bengt H. Fellenius

THIS PAPER deals with the analysis of results from axial testing of vertical single piles, i.e. the most common field test per-formed. Despite the numerous tests which have been carried out and the many Papers which have reported on such tests and the analysis thereof, the understanding of pile test loading in current engineering practice leaves much to be de-sired. The reason for this is that the engineers have concerned themselves with mainly only one question: "Does the pile have a certain least capacity?", finding little of practical value in analysing the actual capacity and the pile-soil interaction. This Paper aims to show that engineering value can be gained from elaborating on a pile test ? during the actual testing in the Held, as well as in the analysis of the results. The first portion of the notes make use of an earlier Paper by the author (Fellenius. 1975). However, additional views and recent literature have been incorporated.

Jan 1, 1988

By Lars Richter, Franz-Werner Gerressen

"The Eglinton Crosstown Line was conceived as the Eglinton Crosstown LRT, a partially underground light rail line, announced in 2007 as part of the Transit City plan, which included the implementation of six other light rail lines across Toronto.There were 43 stops planned for the Eglinton Crosstown LRT, 13 of which would be underground . For those underground stations a lot of specialty foundation works needed to be carried out. King piles, soldier piles with lagging and secant piles were mainly required fulfilling the tasks of installing the retaining wall system.The paper will focus on the original design and alternative solutions, discussing the benefits and limits of these. It will also explain the installation process in general as well as some specific features related to specific site conditions, e.g. limits in installation depth, soil characteristics etc. The required equipment will be explained showing the benefits and limits.INTRODUCTIONThe Eglinton Crosstown project is a 19-kilometre LRT line that will bring much needed relief to the transit woes of Torontonians. Traversing the city in an east-west slice across the midtown artery of Eglinton Avenue, the Crosstown rail line involves a combination of 15 underground stations and 10 atgrade surface stops. It is one of the largest transit infrastructure projects under way in North America today. Aecon has joined partners ACS Infrastructure Canada, Ellis Don, and SNC-Lavalin to form Crosslinx Transit Solutions (Crosslinx).As with many of today’s mega public transportation projects, the Crosstown LRT follows the Public- Private Partnership (P3) model. Aecon is an equal partner in the $5.3-billion Crosslinx consortium to develop the Eglinton Crosstown LRT project in Toronto. Upon the LRT's completion in 2021, Metrolinx, the region’s transit authority and also the project client/owner, will turn to the Toronto Transit Commission (TTC) to operate it. The impact of this highly anticipated LRT line on commuters in the Greater Toronto Area (GTA) is expected to be dramatic and immediate once the first train leaves the station five years from now. In fact, Metrolinx is estimating that within its first 10 years of service, the Crosstown line will be carrying 5,500 passengers per hour (in peak direction) and making 100 million passenger trips annually."

Jan 1, 2017

By Roy A. Imbsen

Following the 1989 Loma Prieta earthquake, California Department of Transportation (Caltrans) expedited an effort to evaluate and retrofit important state-owned toll bridges to en­hance performance of the state's transportation systems during and after major (credible) earthquake events. Imbsen and Associates, Inc. (IAI) along with their sub-consultants, were awarded a contract to conduct seismic evaluation and to develop retrofit design for Benicia-Martinez Toll structure, to meet a "Serviceable" performance requirement after the event of a "Safety Evaluation Earthquake." This paper describes the design and construction specifications for the deep foundations supporting the main spans of the Benicia-Martinez Bridge. Benicia-Martinez Toll Structure (George Miller Bridge), a high-level deck-type welded truss bridge with welded girder approach spans, carries Interstate Route I-680 over the easterly end of Carquinez Strait near San Francisco, CA. The nearly 5000 ft long main truss structure consists of ten spans, ranging from 330' to 528' in length, supported on cellular reinforced con­crete pier structures. Foundation systems across the waterway, consist of cellular reinforced concrete footings, supported by groups of 6' diameter, concrete filled, steel caissons, resting on 5' deep rock sockets, at depths of 50' to 150' below the water level. Seismic evaluation of the existing foundation systems accounted for spatially varying ground motion along the length of the structure, variability of foundation material strength (i.e. at bed-rock), variation and effects of scour depth on the performance of the foundations, and dy­namic soil-structure interaction. Performance of caissons beyond their elastic strength, as well as their effects on the behavior of the foundations and substructures were evaluated and considered in establishing foundation vulnerabilities. Several retrofit strategies were considered leading to a final retrofit strategy to strengthen end connections of existing caissons, as well addition of new caissons to provide adequate lateral force resistance for the foundations. Final design package includes specifications as well as construction methods and requirements for existing and new caissons, under traffic, and pile load testing procedures for design loads of up to 12500 kips per caisson.

Jan 1, 1998

By Haijian Shi, Drew Pizzo

This article focuses on the appropriate application of subsurface investigation methods for transmission structures, which are typically designed to resist lateral rather than vertical loads. Currently, the three methods used most often for the subsurface investigation of transmission structures in the field are the Standard Penetration Test (SPT), the Cone Penetration Test (CPT), and the Flat Dilatometer Test (DMT). Each of these methods has advantages and disadvantages, and each is more applicable to some scenarios than to others. To gain a better understanding of these test methods and the implications of using them for various kinds of applications, a comparison study was conducted in the field in Maryland, for three boring locations. Each boring location was explored using each of the three tests as stated. The results of the tests and lessons learned are presented and compared, and these comparisons show that the three test methods agree on the majority of the findings. The results from each test method were also used to derive key parameters such as the soil friction angle for given foundation designs considered in order to establish a clear basis for comparison. Recommendations for performing transmission structure subsurface investigations are made in order to optimize the use of each method and thereby optimizing subsequent foundation designs. INTRODUCTION For overhead transmission structures, the most important structural requirement for determining the foundation design differs from the requirement for other structures such as buildings and bridges in accord with the conditions the transmission structures will need to withstand. In addition to the ability to bear a given vertical load consistent with its use, the foundation must bear lateral loads arising from wind and other weather conditions. The foundation types used most often for overhead transmission monopole structures include concrete drilled pier, vibratory caisson, and direct embedment. In order to determine an appropriate and even an optimum foundation design for any given set of conditions, an appropriate subsurface investigation method or approach is needed. Currently, the standard penetration test (SPT), the cone penetration test (CPT), and the flat dilatometer test (DMT) are the three most commonly used subsurface investigation methods.

Jan 1, 2018

By Robert B. Bittner

Large diameter piles (2 to 3 m diameter, both driven and drilled) are being used more frequently by designers of bridge foundations. The use of these large piles allows the pile cap to be positioned off the bottom but usually still below water. Conventional cofferdams as shown in Figure 1 below are not suited to this type of pile cap. However, float-in cofferdams offer a viable alternative. This paper describes the float-in cofferdam system, its initial development for use on the Bath-Woolwich Bridge in Maine and its most recent application on the new Carquinez Bridge in California.

Jan 1, 2013

By John J. Vieaux

Allowable loads on Dynamically-Cast-In-Place Piles (the Franki type) can be correlated with N values from the Standard Penetration Test. Using a constant developed by Nordlund, a conservative value for load-carrying capability of a DCIP pile is developed. The DCIP pile and method of installation is briefly described.

Jan 1, 1984

By D. A. Greenwood

Dr David Greenwood opened the first technical session of the conference by highlighting the diverse nature of the papers in this session but drawing attention to the common theme that each solved a particular problem. PAPER 1.1 Tony Elliott introduced his paper on deep mix-in-place soil/cement stabilisation by stressing its simplicity. The engineering solution adopted at Elland was detailed in his paper and had formed the key to success of the project. The process itself is not widely used or known in the UK, although it has the potential to achieve significant benefits, subject to proper engineering control being exercised. It was explained that although the concept was not new, development of the technique for soil modification was relatively recent. The alternatives to mechanical mixing are injection, which is very dependent on soil type, site geometry, etc, and jet grouting; both processes are soil-responsive, and not easily monitored or programmed, difficulties which can largely be overcome by mixing. To achieve this at depths to say 30m requires high-powered, high torque machines and has resulted in significant equipment development.

Jan 1, 1991

By E. R. Wang

This paper outlines the engineering properties of shallow soil in Shanghai area. The main points that should be paid attention to during deep foundation investigation, and general conditions of experimental soil engineering are discribed.

Jan 1, 2010

By Peter Jackson

The dewatering of the large construction pits required for major infrastructure projects often has a significant impact on the environment. This is particularly so in urban areas and where groundwater resources are of interest. These environmental impacts are inter alia, groundwater lowering and the consequent effects such as settlement and deterioration of timber foundations, together with the impact of the dewatering on the groundwater quality. In order to minimise the environmental impact of the dewatering, the quantity of water to be abstracted and the amount of groundwater lowering in the surrounding area must be minimised. This paper describes the measures that have been taken on the Copenhagen metro project to achieve the objective of minimal environmental impact whilst still carrying out a major dewatering scheme.

Jan 1, 2000

By Karsten Beckhaus

"Abstract Tremie concrete for special geotechnical works needs special properties, especially during the casting process. Today’s execution standards for bored piles and diaphragm walls, EN 1536 and EN 1538, as well as the draft version of concrete standard EN 206, all comprise regulations for deep foundation concrete which have not been changed for decades. Considering the recent development in concrete technology at the same time and its actual state-of-the-art, it is essential to develop new normative specifications and specification requirements.GeneralTo allow the required integrity and quality after placing and hardening, concrete for structural elements like bored piles or diaphragm walls, used as foundations of high-rise buildings or as retaining structures for large and deep building pits, must have adequate workability and stability.In addition to requirements on mechanical properties and on durability, both of which have increased within the last decades, concrete must be suitable for being cast in deep or extremely deep excavations, see figure 1. Today’s specialist foundation engineering machinery makes it possible to drill or cut down to in excess of100 m depth. Concrete technology has developed and allows the use of high performance concrete for deep foundations. But is this capability represented by actual regulations?It has become very common for the industry to supply or use concrete with low water cement ratios, nevertheless highly flowable and set-retarded for several hours if needed. Very low water cement ratios allow design strength of 60 MPa or higher (Larisch, 2011), and a very low porosity which is required for a long service life in aggressive conditions, e.g. by chlorides.To achieve best performance, it is obvious that the concrete must completely fill the excavation and fully embed the reinforcement. As vibration of deep foundation concrete is (usually) not allowed and was anyway inefficient, deep foundation concrete must be designed to self-compact under hydrostatic pressure. Generally, it must be considered that after placement the concrete’s quality cannot be influenced anymore. Therefore, both the pouring procedure and the concrete quality must be adequate."

Jan 1, 2014

By Dan A. Brown

The New Mississippi River Bridge (MRB) employed conventional design-bid-build procurement, but the bidding process included the opportunity for pre-qualified bidders to develop and propose confidential Alternative Technical Concepts (ATC?s) for evaluation and approval in advance of bidding. The ATC process provides a mechanism for value-engineering prior to bid, with incentives and opportunities for both the owner and the bidding contractor. The contract described in this paper is for the river bridge composed of a cable-stayed crossing with two pylons and the anchor piers on each side of the river. The Massman-Traylor-Alberici (MTA) team developed a re-designed foundation system for the main pylon and anchor foundations which utilizes their equipment and experience along with field load test measurements to optimize the foundations. The paper describes the experience with the use of the pre-bid ATC process on the project from the perspective of the bidder, and outlines some of the benefits and limitations of this concept with respect to foundation design and construction. Some keys for success are identified and impediments to the effective implementation of the process are described.

Jan 1, 2011