Search Documents

By [D. N. ] Naresh

During different activities pile installation like pile boring, concreting etc., it is likely that various problems, depending up on site condition may be encountered. There are possibilities that some of the activities if not correctly followed may affect the pile capacity. This paper describes few problems encountered during pile execution at different sites and presents the remedial measures undertaken to overcome them.

Jan 1, 1996

By James P. Hambleton, Sam A. Stanier

A perceived advantage of screw-type foundations is the ability infer aspects of foundation performance from quantities measured or observed during installation, especially the installation torque. A particular concept widely used in practice is to correlate installation torque to ultimate capacity. This notion has proven useful as a field verification technique despite the absence of validated models that relate key variables of interest, such as installation torque, axial (crowd) force, geometrical parameters, and soil strength. This paper considers previous work by the co-authors and collaborators on analytical, numerical, and physical modelling of screw piles to relate the quantities measured or controlled during installation (e.g., installation torque) to the ultimate capacity and soil strength. Attention is given to saturated clay as a particular soil type amenable to simplified analysis. An analytical model for a single-helix pile is considered as a means of directly relating the ultimate capacity and undrained shear strength to the installation torque, crowd force, plate pitch, plate diameter, shaft diameter, installation depth, and surface roughness. The connection between the installation variables and ultimate capacity—and the sensitivity to crowd force in particular, a quantity that is typically not measured during field installations—is also discussed. The theoretical predictions are compared against data obtained from small-scale laboratory experiments that suggest the installation torque relates to the remolded strength of the soil. INTRODUCTION Screw piles are deep foundations that are twisted into the ground through an applied torque. Advantages over driven piles or drilled foundations include the relative silence of the installation, with low ground vibrations, and the possibility of being easily decommissioned by reversing the direction of twisting. Screw piles are now routinely encountered as a flexible, low-cost solution for numerous applications (Figs. 1 and 2), and they are also being considered for applications in offshore energy production due to limitations being imposed with respect to decommissioning and underwater noise. Also known as “screw anchors,” “helical piles”, or “helical anchors,” screw piles consist of helices or helical plate elements attached to a central shaft. Figure 3a shows the components of a single-helix pile and key variables. The diameters of the shaft and helix are denoted by d and D, respectively, and p is the pitch of the helix. Variable H denotes depth of the helical plate, and T and N denote the torque and axial (crowd) force applied during installation. In typical applications, the pile includes multiple helical plates, and the shaft is composed of segments that allow for it to extend to large depths into the soil.

Jan 1, 2019

By W. G. K. Fleming

The general history of piling is traced up to the present time with regard to the evolution of methods and materials. The processes have been strongly influenced by developments in basic equipment and industrial change. It is noticeable that in the twentieth century more progress has taken place than in the many previous centuries. It has been strongly influenced by the general development of Soil Mechanics. Test loading is probably the most effective way to assess the success of designs and many empirical relationships have been challenged through it. As we approach a new century it appears that it will be an age of rapid equipment development, with much enhancement of understanding of what has been done. Processes of automatic construction and testing will becoming commonplace. These changes will narrow the limits of conventional scatter that have come to be accepted and to a large extent will be driven by political efforts to curtail energy consumption, to raise standards of quality and reliability, and to conserve the environment. 1. Ancient history. Piling is an ancient art. Its first mention in history is from Herodotus, the first person to commit an account of his times to the written word in the years 557 to 479 BC. He evidently had a strong interest in engineering matters because he wrote of building, brick making, reinforced brickwork, river training, canal building, bridge construction, tunnelling and its acoustic detection and piling. The piling reference comes from Book 5 at paragraph 16.

Jan 1, 1999

By F. W. Liang

The geology of pearl River estuary belongs in strong weathered rock quaternary geological systen, so the conditions are complication. Since 80's we built the first deepwater wharf of Shenzhen chiwan port which has 3 berths of 10000 dwt, We have built 3 berths for vessels of 40000 dwt both in Shekou Port and Chiwan port. The berths for carriers of 10000 dwt in Yantian Port of Dapeng Bay are constructing now. In the five years, We built more than 20 deepwater berths of 5000 dwt to 40000 dwt. This paper will introduce how to solve the difficulties of the complex geological conditions and how to use the new fashion construction. We will reduce the period of engineering construction and get good quality and make a good beginning of rapid development of port construction in ShenZhen Special Economic Zone.

Jan 1, 1991

By Bolestaw A. Ktosihski

Preloading of bored pile bases by grouting is an effective way of reducing foundation costs. The bearing performance of a pile may be considerably improved. Various techniques and devices are used. Preloading of a pile base by a special grouting installation is preferred. The grouting device consisting of a U-shaped grouting tube with sleeves and a plastic membrane, separating the tube from the pile concrete, has well proven in Polish practice. The preloading may raise the pile design loads by as much as 30%, and increase their stiffness by 50%, in suitable conditions. The preloading equalizes the deformability of piles in a foundation or a structure. Examples of the base preloading use and load tests of base grouted piles are presented.

Jan 1, 2006

By Patrick J. Hannigan

The pile foundation designer typically performs a subsurface exploration program and static pile capacity calculations before selecting a pile foundation type, length, and capacity. During construction, a pile installation criterion must be established to meet these design requirements. This installation criterion usually consists of a minimum penetration resistance or blow count to confirm pile capacity and may also include a minimum embedment requirement. This text will focus on use of wave equation analysis and dynamic measurements to meet design requirements. BEFORE THE WAVE EQUATION Since the mid-1800s, over 450 dynamic formulas for pile driving control have proliferated. In their simplest form, these formulas relate hammer energy to the work of soil resistance, or simply: W ? h = R ? s (1) Where W = ram weight h = ram drop height or stroke R = pile capacity s = pile penetration per blow

Jan 1, 1990

By Wu Jie Mei, Li Yao Liang, Franz-Werner Gerressen, Arthur Bi

Diaphragm walls (D-walls) are known as underground structural elements commonly used for retention systems and permanent foundation elements. In addition, they are also quite often used as deep groundwater barriers, called Cut-Off-Walls (COW). Shanghai ranks third among the most densely populated metropolises in the world. In 1990, only eight million people lived there. Today, Shanghai has about25 million inhabitants. The increasing demand to accommodate the infrastructure of growing megacities like Shanghai pushes the required depth for subway, sewage and foundation projects to the limit. Future projects will demand excavation depths of more than 100 m (328 ft) on a regular basis. Already carried out reference projects will be described and a general outlook for upcoming projects will be given. The paper also explains the installation process in general focusing on the use of trench cutter technology. INTRODUCTION D- walls are known as underground structural elements, commonly used as retention systems for excavation pits and shafts as well as permanent foundation walls or elements. It is anticipated that, with the increasing trend of utilizing more and more underground space to accommodate environmental considerations and urban/suburban development, there will be an increasing requirement for diaphragm wall usage in even more difficult conditions and with increasing depth. The trench cutter is the most important tool for performing this work. The hydraulic grab, a well-known and valuable excavation tool for d-walls reaches its limits in terms of depth and when cutting rock. Therefore the trench cutter technology will be in the focus of this paper. The trench cutter itself is a reverse circulation excavation tool. It consists of a heavy steel frame with two drive gears attached to its bottom end, which rotates in opposite direction around the horizontal axis. Cutter wheels are mounted onto the drive gears. As they rotate, the soil beneath the cutter wheels is continuously broken up, removed, mixed with the bentonite slurry in the trench and moved towards the opening of the suction box of the pump? A centrifugal pump located right above the cutter wheels conveys the slurry via a hose system up to a desanding plant. There the slurry loaded with soil and rock particles is cleaned and returned into the trench.

Jan 1, 2018

By Shahid Islam, Lucian Bogdan

Deep and large diameter drilled shafts use mostly bundles of Grade 60 (415 MPa) reinforcing bars as longitudinal reinforcement with rebar splices to make it longer. Lower Grade steel requires large number of bars which result in rebar congestion and difficulty in placing concrete. This leads to increased labor cost for fabrication and installation. By utilizing larger size and higher strength threadbar, the congestion of rebar can be reduced significantly and bundling of bars can be avoided. The lap splices are replaced with simple threaded couplers and end hooks are replaced with end terminators. Threadbar conforms to ASTM A615-15 and can be epoxy coated if required for corrosion protection. This paper describes an attractive value engineering of replacing Grade 60 (415 MPa) bundle of rebars with larger diameter Grade 75 (515 MPa), Grade 80 (550 MPa) and Grade 100 (690 MPa) threaded bars and threaded couplers in some specific drilled shaft projects in the USA. INTRODUCTION A drilled shaft which may also be referred to as drilled piers, caissons, cast-in-drilled-hole piles and bored piles is the key element to the foundation of massive structure. They are used for tall buildings, bridges and foundations for other applications such as retaining walls, sound walls, signs, or high mast lighting. Drilled shaft foundations are typically 3 to 12 feet (0.9m to 3.7m) in diameter cast-in-place deep foundation elements constructed in a drilled hole that is stabilized to allow controlled placement of reinforcing steel and concrete. Drilled shafts for transportation structures are commonly used to depths of up to 200 ft (61m) in the USA. Drilled shafts can be installed in a variety of soil and rock profiles, and are most efficiently utilized where a strong bearing layer is present. The reinforcing cage is typically lowered into position within the hole and then concrete placed through the center of the shaft, flowing from bottom to top through the reinforcement to fill the hole.

Jan 1, 2018

By Thomas Lardner

Excavation for The Bow, EnCana, in downtown Calgary, occurred between May 2007 and September 2008. A monitoring programme was used to determine the behaviour of the shoring wall, soil and bedrock during the excavation for the 21 metre (69 ft) deep excavation with a footprint of approximately 17,000 m2 (183,000 sq ft). Results from the inclinometer readings indicated that significant horizontal movement due to a weak rock layer and shear band effect. These modes of movement account for up to 100 mm (4.0 in) and 45 mm (1.8 in) of lateral deflection, respectively. Based upon the results of the monitoring programme, rock samples were collected from the weak mudstone bedrock, with great difficulty, to determine the strength and deformation parameters. Results from the uniaxial compression tests indicate a UCS around 830 kPa (120 psi) and elastic modulus between 80 and 180 MPa (11 and 26 ksi). Mohr-Columb parameters were determined to be c' = 340 kPa (49 psi) and f' = 24°. Residual strengths were determined to be c'r = 0 and f'r = 15°. Using the results of the laboratory tests and field investigation records, an initial finite element analysis was conducted. Results of the analysis show good correlation when compared with the observed monitoring deformation, indicating accurate portrayal of rock parameters. Additional analysis and investigation is required to determine the principal horizontal stresses in magnitude and direction.

Jan 1, 2010

By Jorj O. Osterberg

Until ten years ago, the largest load tests on drilled shafts (bored piles) were about 3,000 tons (27MN). These tests were made with kentledge (large weights, usually concrete blocks) stacked up as a reaction to the applied downward load of a hydraulic jack. In some cases, the jack load is resisted by a load frame held down by piles or anchors connected to the frame. When the test loads exceed 3,000 tons (27MN), these methods become cumbersome expensive and time consuming. The Osterberg (O-cell) test method does not require any reaction load. It has become the only cost effective method for static load testing of high capacity shafts. Over 650 load tests have been performed with this method, 86 of which were over 3,000 tons (27 MN) and 40 over 5,000 tons (44 MN), and the largest test load was 17,000 tons (150 MN). Tests have been made on sands below the water table, shafts ending in rock sockets, and cemented sands and gravels. Test results and details for selected load tests are discussed.

Jan 1, 2002

By Harry G. Poulos

Ground movements can arise from a large number of sources and can have a significant effect on nearby piles and deep foundations. The loading of the piles by ground movements is a different mechanism to that arising from direct applied loading to the pile head, and consequently it is not generally possible to adequately analyze the effects of ground movements simply by applying some type of equivalent loading to the pile head. The main effects of ground movements are the development of additional movements, axial forces and bending moments in the piles, and thus the key design aspects are related to movements and to the structural integrity of the pile. However, the ultimate geotechnical load carrying capacity is generally not affected by the ground movements themselves. This paper will describe an approach to the analysis of ground movement effects on piles, considering axial and lateral movements separately. Some of the main features of pile response will be discussed for three specific problems involving ground movements: 1. Piles near and within embankments; 2. Piles near an excavation for a pile cap; 3. Piles subjected to seismic ground motions.

Jan 1, 2007

By Robert Jakiel

The following paper is being presented to provide a basic understanding of the equipment and procedures used in multi-auger deep soil mixing as part of the program for the Deep Foundations Institute (DFI) Deep Soil Mix Seminar. The paper is written as a summary of the author's experience using multi-auger deep soil mixing equipment while working with SMW Seiko, Inc. on several east coast projects in the United States, particularly the soil-cement mixing for the soil stabilization of the Fort Point Channel area in Boston, Massachusetts, one of the largest and most difficult soil mixing projects completed thus far in the United States. The summary provides a brief summary and insight into some of the operational aspects of the equipment and procedures, and some of the important considerations when using multi-auger deep soil mixing. This paper is intended for use by both the contractor and the designer involved in selecting appropriate soil mixing equipment and procedures for various types of soils, depths or applications, or for a better understanding of the operational aspects, potential benefits, and impacts that the performance criteria may have on the operational capabilities of the soil mix equipment, when specifying multi-auger soil mixing for a particular project. Prior to reading this article it is important to become more familiar with the various acronyms and terminology used in soil mixing technology. A Definitions section has been provided at the end of the paper that will help the reader become more familiar with some of the terms used throughout this paper.

Jan 1, 2001

By Andrzej Tejchman

Calculation of pile foundations should possibly truly reflect its real work, mainly with respect to the value and distribution of settlements, pile internal forces and bending moments within a slab. Many empirical and theoretical methods serving for an assessment of the settlements of pile group overestimate its actual values obtained from field measurements (see Tejchman et al., 2001). In the paper a simple engineering method for calculation of pile foundations is presented. The method takes into account the interaction between the slab and a soil together with the phenomenon of non-uniform deformation of the soil-pile subsoil, particularly under large foundations. In the method the scheme of the slab resting on one-parameter elastic subsoil is assumed. The comparison of the calculation results for existing pile foundation with the field measurements shows good agreement between those values.

Jan 1, 2002

By Xu Ronglie

This paper looks back on the developments and achievements of deep foundations, on the basis of the complex geological conditions and environments in China. It sums up advances in theoretical and applied researches, engineering constructions, practical experiences, case histories, and problems and developing prospects of piles and deep foundations in recent years in China.

Jan 1, 1991

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 Karen C. Armfield, Gisele R. Passalacqua, Joanna Smith

When selecting a solution for improving resiliency at facilities, such as airports, utility and transit sites, there are many options to protect structures and equipment against potential flooding. Each case involves an evaluation of the several key factors such as: design flood parameters, the geography and geological conditions below the site, the facility, and the layout of buildings and equipment to be protected. Upon reviewing these conditions and conducting a cost analysis of various options, the most suitable approach to protecting a facility can be determined. This paper will compare the conditions at various New York City sites, and give detail to the solutions utilized at these sites to improve resiliency and protect each facility. Flood wall types varied as did the strategies for raising critical equipment, to meet the Federal Emergency Management Agency (FEMA) and American Society of Civil Engineers (ASCE) 7 guidelines. Due to granular soil conditions, some sites may experience soil seepage below the flood wall resulting in the need for underground cut off systems. The authors will also present detail regarding the solutions used to control seepage. Various cut off systems will be discussed such as grouting and sheeting, explaining the factors that may impact the choice of systems. Another consideration in flood resiliency is the potential for a buoyancy condition on basement slabs when localized flood barriers are employed on first floor doors and windows. The authors will discuss the potential impacts of this condition on facilities and methods to mitigate this issue. 1. INTRODUCTION New York City is an urban coastal Metropolis with varied geology and low land areas. This includes but is not limited to sandy soils at Coney Island and the John F. Kennedy Airport. Soft marshes are found near Flushing Queens and LaGuardia Airport. Heavy rains and coastal storms caused disruption to daily life and heavily affected the economy of this vibrant City. For instance, in lower Manhattan business was interrupted in the Financial District. Power outage was widespread; commuter trains and subways were stopped and put out of service. Additionally, numerous residential homes were damaged in Coastal Neighborhoods such as the Far Rockaways and Staten Island. 1.1. Superstorm Sandy Flood Statistics On October 29, 2012 Superstorm Sandy impacted numerous facilities in the New York City Metro area. The resulting damage cost New York City more than $42 billion in repair costs. $33 billion was allocated to repair housing and infrastructure, and $9 billion was allocated to protect transit systems1. One of the major issues that impacted the city in terms of its preparedness was the high flood surge. The surge surpassed the former base flood elevation and reached as high as 13.88 feet (above mean lower low water - MLLW) in Battery Park at 9:24pm that evening. Tottenville, Staten Island experienced more damage where the water was recorded at +16 (North America Vertical Datum of 1988 - NAVD88), which is equivalent to 18.7 feet above MLLW (see Fig. 1). Not only was the surge at record levels, the waves in New York Harbor were also at record level where some buoy stations recorded waves of up to 32.5 feet. The City released “A Stronger, More Resilient New York” in June 2013, a plan laid out to rebuild communities impacted by Sandy and improve the resiliency of the infrastructure and buildings in New York City. Figures below help to illustrate the extent of the inundation relative to the projects being discussed.

Jan 1, 2018

By K. Rambha Devi

The paper is an attempt to co-relate the findings of pile capacity using a number of formula suggested by various authors with the actual field load test results. Five locations consisting of wholly sandy or clayey soils were selected for this purpose. The clayey soils are on a hilly area having clays of medium to stiff consistency upto a depth of 20 m The sandy soils are near the bank of a river having angle of internal friction 'Ø' value ranging from 30 to 35 Degree. The details of the soil properties are given in Table-1 Bored cast-in-situ piles of 30 cm diameter and a length varies from 6.5 m to 13 m were designed and cast for load test to be carried out. The load applied was twice the design load. The load vs settlement curves were obtained. The theoritical values obtained by formula suggested by various authors were superimposed on the curves. From the careful study of these curves it is seen that De Ruiter and Berigen values are close to the actual results for clayey soil. For sandy soil it is found that both the BIS method and Meyerhof method found to give conservative resuslts. A multiplication factor is suggested to theoritical values for obtaining satisfactory results.

Jan 1, 1996

By Chris Harnan

This paper describes the geology of three European cities and outlines how the geology has lead to the development of specific foundation construction techniques. Comparative tables of techniques commonly employed are given in Section 5. It can be seen that despite the presence of the 'single market', techniques still have wide diversity despite some similarities in geotechnical conditions.

Jan 1, 2000

By Sridhar Krishnan

This paper presents the results of a comprehensive pre-production pile testing programme for the US$ 800 million 1400MW Coal-Fired Jimah Power Plant Project in Negeri Sembilan, Malaysia. The testing programme included high-strain dynamic testing and fully instrumented static axial and lateral load testing of driven prestressed concrete piles and bored cast-in-place piles. A highlight of the testing programme was the pioneering use of the Global Strain Extensometer (GloStrExt) Method, a deformation monitoring system that uses advanced pneumatically- or hydraulically-anchored extensometers and a novel analytical technique to monitor loads and displacements down the shaft and at the toe of driven prestressed concrete piles. The experience with the testing programme for the Jimah Project also demonstrates the possibility of achieving notable breakthroughs, not only in the monitoring, evaluation and reporting of pile foundation behaviour dynamics but also in our understanding of the mechanisms that underpin such behaviour. These significant gains are undeniably a direct result of the committed and co-operative relationship among the project owner, design/builder, specialist piling subcontractors, pile suppliers and pile instrumentation and testing specialists.

Jan 1, 2006

By Gregory J. Canivan

Three test pile programs were conducted in Charleston, South Carolina to evaluate differences in bearing resistance due to installation methods. The tested piles were installed with impact hammers and vibratory drivers through soft clays and/or loose sands into the Cooper Marl, a stiff calcareous marine clay or silt. Piles driven into the Cooper Marl experience significant capacity gain with time following initial installation due largely to pore pressure dissipation. Pile size and pile type were both known to affect pore pressure generation during installation and subsequently the capacity gain with time. The test programs were primarily conducted to optimize pile design values and construction methods with regard to trestle construction but the results also contribute to the understanding of driven pile behavior. High strain dynamic testing was performed on several open-end pipe and H-piles. The measured difference in long-term bearing capacity of the H-piles as a result of the two installation methods was negligible, while the short-term bearing capacity of the pipe pile was larger when the piles were installed using impact hammers. The lower short-term resistance in the vibratory driven piles is attributed to larger excess pore pressures generated during installation compared to those generated during impact driving.

Jan 1, 2002