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By Maurizio Siepi

The realisation of most of the civil engineering works is subordinate to the execution of consolidation works, in order to improve the soil physical-mechanics characteristics. The works classifiable with the term "Soil Improvement" can be realised using several technologies, among which the Deep Mixing Method is distinguished for his remarkable flexibility and productivity characteristics. The Deep Mixing Method is a process whereby a rotary drilling machine mechanically drills a constant diameter hole while cement slurry is injected into the soil at high pressure. The process combines state of the art construction techniques merging mechanical and hydraulic mixing energies at the tool bit. The result is a soil-cement column of engineered strength, consistency and dimension. Whereby the soil cement column formation process is controlled by a computerised device, the result is a speedy installation, thorough mixing, and a high degree of control, repeatability and documentation.

Jan 1, 2002

By L. C. Reese

? Good construction and inspection presumed. ? Capacity-computation factors are independent of construction method. ? To account for variable or uncertain site conditions, anticipated construction problems, and/or minimal inspection, increase factor of safety. ? Conduct load tests and/or develop easily implemented design alternates (e.g., straight shaft in case bell can't be formed) to reduce factor of safety.

Jan 1, 1988

By Mait Mets

In Estonia, the deformations monitoring of 1500 buildings are currently under investigation, buildings on pile foundations make up 10 per cent of these. In the following text we will be considering the behaviour of pile foundation buildings in various parts of Estonia, in differing geotechnical conditions.

Jan 1, 2002

By Ahmad F. Souri, Murad Abu-Farsakh

"In this study, the static lateral resistance of vertical and battered pile groups was analyzed using 3D finite element analysis. The battered pile group finite element model was verified using the results from a case study performed on the M19 pier foundation of the I-10 twin span bridge in Louisiana. The vertical pile group model was created by adjusting pile inclinations of the verified battered pile group model. The finite element models utilized nonlinear constitutive models for materials behavior and a soil-pile interface model. The results showed that the battered pile group had greater lateral resistance than the vertical pile group with 60-70% lower pile cap displacement. The largest lateral load share was found in the middle rows in the battered pile group, while it was in the leading row for the vertical. The soil resistance profiles showed that the vertical pile group mobilized greater soil resistance compared to the battered pile group.INTRODUCTIONThe lateral resistance of a pile-soil system depends on both pile stiffness and soil reaction. The soil reaction is a nonlinear function of deflection, depth, pile stiffness, and soil stiffness and strength. The lateral capacity of single piles is evaluated at the maximum deflection limit, and can be predicted using established methods such as the p-y curve method (e.g., Matlock 1970, Reese et al. 1974), elastic solution by Poulos and Davis (1980), the strain wedge model (Ashour et al. 2004), and the finite element method (e.g., Yang and Jeremic 2002, Comodromos and Pitilakis 2005, Isenhower et al. 2014). For pile groups, the lateral capacity of a pile-in-group is less than the isolated single pile case because the soil in front of the pile-in-group is weakened by the overlap of stress zones from surrounding piles. The latter is referred to as the shadowing or group effect (Fig. 1). Prediction of the lateral capacity for pile groups is based on the p-y curve method for single piles with the use of empirical factors called “p-multipliers”. The p-multipliers accounts for the shadowing effect, and are a function of pile-pile spacing and soil type (e.g., Brown et al. 1987, 1988, McVay et al. 1995). Moreover, the lateral capacity of pile groups is also influenced by vertical load, piles arrangement, and slenderness ratio (e.g., Rao et al. 1998, Patra and Pise 2001, Ilyas et al. 2004, Hussien et al. 2012).Battered piles refer to piles installed at an angle with respect to the vertical to increase their lateral capacity. The greater lateral resistance is achieved by the additional axial reaction in the pile. Battered piles are called “negative battered” when inclined in the load direction, and “positive battered” when inclined opposite to the load direction (Fig. 1). Previous studies concluded that the lateral resistance is highest in positive battered piles followed by negative battered and vertical piles, respectively (Murthy 1964, Meyerhof and Yalcin 1993, Zhang et al. 1999)."

Jan 1, 2017

By Samuel J. Kosa

The Monotube is a uniformly tapered high-strength steel shell pile manufactured for friction pile applications. The Monotube pile was developed in the early 1920's in Canton, Ohio. Its first commercial installation was an Ohio railroad trestle in 1926. The Monotube has been manufactured in the same Canton plant since its inception. The Monotube is produced in four diameters, 12, 14, 16 and 18 inches, with U. S. Standard Gage wall thicknesses of 9, 7, 5 and 3. The uniformly tapered Monotube section can be manufactured in one of three rates of taper.

Jan 1, 1993

By Mike Fabius

The Lakehead Region Conservation Authority is responsible for slopes along the Kaministiquia River, one of the largest tributaries to Lake Superior in Canada. After arresting toe erosion for a mile of riverbank, the remainder of the slope required stabilization to stop further crest regression and to protect the houses, street and services at the top. Stabilization of the 100 ft. high slope was tendered as design-build with a target safety factor of 1.3 and a design life of 75 years. The successful bid was a system of 1.4 inch diameter soil nails up to 40 feet long, installed perpendicular to the slope on a 3 to 5 foot grid. The conventional shotcrete facing was replaced with a ?green? biotechnical facing and special transverse plate heads on the nails. The key to keeping costs low proved to be installation with light equipment working on the slope, and driving the nails without drilling or grouting. Rather than tension, the design was based on bending in the nails, similar to a laterally loaded flexible pile. The paper describes the design and installation of this innovative system. The design is discussed in terms of soil properties, nail resistance as it varies with depth, failure modes, corrosion protection, root design and nail head design. Construction challenges are discussed. The system is compared to an adjacent anchored soldier pile wall built along the same slope 20 years ago. Post construction monitoring results confirm predicted performance.

Jan 1, 2006

By Clifford Taylor, Alexander Zöhrer

"The execution of deep basement excavations under narrow conditions is one of the most challenging tasks in geotechnics. The vicinity of neighbouring buildings, roads, and underground structures such as sewers or power lines, quite often prohibits the application of standard solutions. In addition, legal considerations in the use of adjacent properties is becoming increasingly difficult. This paper will present some innovative approaches to overcome the above-mentioned challenges based on several case studies from central Europe. For every project the design approach as well as the techniques used for execution will be explained, detailing both the advantages and the limitations of the applications. One case study shows a deep basement excavation (approx. 17m) in the centre of Prague, Czech Republic. This project featured many challenging boundary conditions (narrow construction area, high ground water table, jet grouting column embedment into bedrock, constraints regarding use of ground anchors due to property rights, etc). The realisation of the complex design is described and illustrated in detail. Other case studies will show the combined application of bored piles with jet grouting and also explain the design of vertical prestressed anchors for retaining walls.INTRODUCTIONThe development of urban areas has always presented challenges, from access for equipment and materials to the rectification of existing foundations in unknown condition. Compounding these is the increasingly stringent requirements to retain, maintain and reduce impact on culturally and historically significant structures. As available space is becoming more limited, optimisation of real estate has resulted in buildings getting higher and their basements deeper below ground. Two or more basement levels are quite common, with typical excavation depths ranging from 5 to more than 10m. Additionally, we are faced with neighbouring buildings that are equally high, deep and massive. These buildings directly adjacent the retaining structure require underpinning to limit settlement, and in cases where they are within just a few meters, this building mass generates additional earth pressure for the retaining wall to support, resulting in complex loading cases.This paper highlights several common challenges and explores the measures implemented to overcome them. The challenges and examples of either design based solutions or practical applications will focus on the following topics – the limitations of conventional geotechnical construction methods, overcoming challenging geology and the requirement for watertight basement constructions."

Jan 1, 1900

By K Ilamparuthi, R. K. Madhumathi

"This paper presents the results of 1g model tests conducted on model piles both single and two pile groups embedded in sand by physically inducing lateral soil movement. From the test results it was found that the pile with higher L/D ratio exhibits higher deflection in case of pile embedded in medium dense sand whereas in loose sand the response is vice versa with higher deflection for the pile of lesser L/D ratio. The induced bending moment in piles is more for longer piles than shorter piles irrespective of the density of sand bed. It is also found that the pile head deflection and the bending moment are found to decrease exponentially with increasing distance between the pile and the wall. For pile group arranged in a row parallel and perpendicular to retaining wall, the deflection of single pile is more than the deflection of two pile group irrespective of the depth of excavation for spacing of piles tested. The influence of soil movement on the lateral response of pile is also analyzed through 3-dimensional finite element analysis. The numerical results thus obtained are validated with the results of experiments. The Mohr-Coulomb material model adopted to represent the soil behaviour predicts the response of pile reasonably and compares well with the experimentally observed response.INTRODUCTIONPile foundations are adopted to support structures such as foundations of high rise buildings, transmission towers, offshore platforms, bridge abutments etc., when good bearing stratum is not present at shallow depth to bear the loads of these structures. In the recent past particularly in the urbanized areas structures are built close to one another and nearby excavation will cause a reduction of lateral earth pressure and soil movement behind the retaining wall (Ong, 2004). The reduction in support stress will induce additional movement to the pile and leading to distress in pile foundations located adjacent to supported excavation. In these situations understanding the response of piles next to supported excavations becomes essential.The behavior of piles subjected to soil movement was studied by Poulos and Chen (1996 and1997) through tests on 1g models and the findings concluded that the maximum bending moment was found to decrease with decreasing pile diameter and decreasing pile spacing . Leung et al. (2000 and 2003) studied the effects of excavation induced soil movement on pile foundations in sand through centrifuge tests and established that the restraints on the pile head would cause additional shear force and/or bending moment at the pile head, although the restraints help to reduce the pile head deflection/rotation. In the theoretical studies of Poulos & Chen (1997), boundary element method (PALLAS) was used for analysing the pile subjected to lateral soil movement and charts were proposed for designing the piles. Pan et al. (2002) and Miao et al. (2006) analysed the passive pile behavior through three dimensional finite element analyses. However research works reported on piles subjected to lateral soil movement are limited."

Jan 1, 2015

By Alan B. Wagner

The River Tower is a proposed 27-story condominium building in the heart of downtown Milwaukee, Wisconsin (USA). The tower will be over 100 m tall, and will have a ground area measuring 15 m by 40 m. The structure will be constructed of cast-in-place reinforced concrete. Certain transfer girders and stabilizing diagonals will be constructed of post-tensioned concrete. Vertical loads will be transmitted through an arrangement of columns, bearing walls, and elevator and stair cores. A mat foundation will be used to connect and integrate these load-carrying elements. The site's geologic profile includes 8.4 m of compressible estuarine (organic) deposits. To control settlement, the mat will be pile-supported. These deposits are underlain by moderate-strength inorganic deposits that extend to bedrock at 32 m.

Jan 1, 2002

By Colin C. West

On August 7, 1986, Barge 45, while being towed near the mouth of the Niagara River, was swept downstream and pinned against one of the central piers of the Peace Bridge. The barge rested against the pier with 125 feet overlying the Canadian border and 50 feet overlying the American border. The tug boat which was towing the barge was lost further downstream. Fortunately, the crew escaped and were rescued with no loss of life. There was serious concern about the potential erosion effects of the river currents on the foundation of the bridge pier as caused by the flow concentrations around the barge structure. Due to the time of year, with the approaching Fall and associated worsening weather conditions, it was imperative that the barge be removed as soon as possible. Donjon Marine of New Jersey, the United States Navy's Atlantic Zone Contractor, was called on to retrieve the barge. By this time the original owner had abandoned the wreck.

Jan 1, 1987

By George G. Goble

The use of augercast piles has been limited by the engineer's concern for the structural quality of the installed pile. The nature of the pile is such that its final structural continuity is very dependent on the skill of the personnel that do the installation. Thus, NDT methods have been used to verify integrity and when problems are indicated the available solutions are usually quite costly. If information were available during the pile installation so that immediate steps could be taken to correct perceived problems, the concerns of the engineer could be addressed and the system would gain increased reliability. Pile Dynamics, Inc. has developed a quality control system, the Pile Installation Recorder for Augered Cast-in-Place piles (PIR CFA). This system consists of the following devices as shown in Figure 1. 1) The Control Unit powers the sensors, conditions the signals from the sensors, records all measurements, takes input information from the operator, displays the results, and stores the recorded data on a flash card for later permanent storage and processing. During the use of the system all of the results obtained during a test are seen during recording and can be reviewed on the screen again after completion of the installation. The ability to review the measured information makes it unnecessary to print a copy in the field. Since printers often give difficulty in the construction site environment the ability to review the results quickly after completion of the installation is an important capability.

Jan 1, 1997

By Stuart Hardy, Xiangbo Qiu

The South Bank Place project comprised the redevelopment of the iconic Shell Corporation headquarters in Waterloo, located on the Southbank of the River Thames in central London. The site was originally developed in the 1950’s and due to the monitoring of the underlying Bakerloo Line tunnels by the Building Research Station it has become a seminal case history for the long term swelling behaviour of London Clay. The redevelopment, undertaken by a joint venture of Canary Wharf Group and Qatari Diar, included demolition of the existing building (with the exception of the main towers) retention of the existing basement structure and the construction of eight new mixed use buildings, up to 31 storeys in height. The foundations for the new buildings varied according to the building height and the below ground constraints. Two of the buildings are partially founded in reused under reamed piles that were installed as part of the original 1950’s development. The paper describes the novel methodology developed to assess the re-use of the under reamed piles which builds on the guidance published by CIRIA and the BRE for straight shafted piles. The paper also describes the physical investigations and numerical analyses undertaken as part of the assurance process and the procurement of latent defect insurance by the client.

May 1, 2022

By Derrick D. Dasenbrock

Three piers of a new river bridge are supported on 1.067 m diameter open-end steel pipe piles. At time of drive, and after pile re-strikes, high-strain dynamic capacity values at plan tip elevations, were as low as 23% of design requirements. Pile lengths were extended 20% to 40% deeper than planned at two piers, driving to rock, impacting both the project cost and schedule. The significant discrepancy between predicted and observed capacity was investigated through a series of coordinated dynamic tests; a full-scale test pile was installed and monitored over 221 days by both dynamic and quasi-static methods. Unusually slow strength gains were observed by dynamic monitoring on all piles installed at the site. CPT soundings were advanced at the test pile and through the pile interior to investigate the soil plug. High-strain dynamic methods were found to have significant limitations in properly assessing the long-term capacity of large-diameter open-end pipe piles during driving and short-term pile re-strikes. As the benefits of large diameter high-capacity open-end pipe piles are numerous, the geotechnical community needs to address appropriate construction monitoring and control of these foundation types to take full advantage of these systems. An improved understanding of the physical effects of pile installation and the impact on soil strength assessment while driving and long term soil strength gain should be developed and incorporated into both design and monitoring procedures to avoid either unsafe or needlessly costly designs.

Jan 1, 2006

By Chris Leach, Lucie Spencer

This case study describes the geotechnical aspects of the basement construction for a multi-storey, residential and hotel complex located in the newly developed Elizabeth Quay precinct in Perth, Western Australia. The development included a three-level basement for car parking covering the full site area which was constructed using the top-down construction sequence. Soil conditions generally comprised 2m of fill overlying medium to dense clayey sands that in turn were generally overlying a very stiff clay stratum at approximately 13m depth. Bedrock level was generally encountered at approximately 22m to 35m below ground level. The ground water table was at a depth of approximately 1m below the existing ground surface level. A site boundary basement wall was constructed using a diaphragm wall retention system. The majority of the vertical loads from the building were transferred to the Kings Park Formation (KPF) bedrock through the use of foundation piles constructed by the CFA method. The CFA piles were installed from existing ground level, resulting in approximately 9m sacrificial concrete length from pile platform level to basement 3 (B3) level. The permanent column loads are such that a single CFA pile was not structurally adequate. To allow a full CFA foundation system to be adopted, an innovative design and construction approach was developed for these heavily loaded columns. This paper discusses the site technical details and the design and construction aspects required to meet the challenges offered by this project.

Nov 1, 2022

By J. Nakayama

Down-the-hole hammer is commonly recognized as the most powerful drilling equipment for weathered to fresh rock formation including boulders. However, its drilling diameter is restricted by reasons of difficulty to actualize large diameter drillhead and to ensure discharging means of cuttings. Cuttings are usually removed by flushing i.e. uprising return air after compressed air actuates hammer, but in case of large diameter drilling, as the clearance between drill rod and surrounding wall of hole become fairly large, necessary up-hole air velocity to transport cuttings can not be maintained. In case of marine or underwater drilling or high groundwater table, orthodox down-the-hole hammer is obstructed its operation by water. This single head hammer drill combined large diameter drillhead with reverse circulation of drilling fluid enables large diameter drilling extending to 1.5 m, i.e. actualized large diameter mechanical drillhead incorporated with ensured cuttings removal means enabled this range of drilling. This paper introduces its features and actual applications to large diameter bored pile drilling for varied sorts of rocks in maritime construction projects.

Jan 1, 1996

By Ryan Weaver, Travis Coleman

The drilled shafts that support transmission lines and substations have been increasingly subject to testing to assess the integrity of placed concrete. Cross-hole Sonic Logging (CSL) has been used, but large diameter shafts with challenging site access are generally more favorable to Thermal Integrity Profiling (TIP) testing. TIP testing assesses the shafts based on measurements of the concrete temperature during curing. The TIP results provide assessment of integrity both within and outside the cage, along with information about the alignment of the cage and concrete cover. This data has allowed shafts with imperfect results to be subject to more detailed structural evaluations. However, it may not be well understood how to use this additional information by designers and engineers. The purpose of this paper is to present TIP results of transmission line foundations, both with and without issues with integrity, including cage shifting, minimal concrete cover, or soil inclusions. The intent is to provide general guidelines of the issues that merit additional investigation and those that should be recognized as inconsistencies inherent to underground construction. BACKGROUND This paper is intended to discuss some of the drilled shaft evaluations made when TIP testing is performed. The authors of this paper were recently involved with a transmission line project that was designed and constructed for a Confidential Utility Client located in the Midwest United States. The project was delivered as an Engineering, Procurement, and Construction (EPC) contract with the electrical line construction company as the prime contractor. The contractor then subcontracted several parts of the work which included engineering for transmission line and foundation design, foundation construction, and third-party testing intended to evaluate the concrete homogeneity and integrity of the place concrete in the deep foundations. The testing method selected was Thermal Integrity Profiling Method B, which uses thermal sensors embedded in the concrete. The TIP testing was administered by Mr. Travis Coleman with GRL Engineers, Inc. Mr. Ryan Weaver with Burns & McDonnell served as the owner’s engineer and technical consultant for the utility and was responsible for reviewing submitted TIP reports and providing recommendations to the utility on their acceptance, and if there were any issues that would warrant further discussion and analysis.

Jan 1, 2019

By Jorge Beim

Helical Piles are increasingly being used to support and rehabilitate structures subjected to compressive axial loads. Traditionally, empirical correlations between installation torque and load capacity of helical screw piles are used as the field quality control. Load tests, however, are always recommended to validate the installation process and design methodology. This paper describes a test program performed on helical piles installed at the National Geotechnical Experimentation Site of the University of Massachusetts - Amherst campus (UMass-Amherst), well known for its deep varved clay deposit. Seven of these piles were submitted to Dynamic Load Tests using the Pile Driving Analyzer® (PDA), and also to Static Load Tests. Good agreements were obtained between the results of the dynamic and static load tests, encouraging the use of the former testing method as a viable alternative to the latter for determining the compressive load capacity of helical piles installed in cohesive soils. The results of the load tests were also compared to the predictions based on torque correlations, resulting in correlation coefficients which were higher than the ones traditionally used.

Jan 1, 2012

By David White

When finished (projected completion in 2016) the Hong Kong-Zhuhai-Macau Bridge Project will comprise three cable-stayed span bridges and a 4.15 mile immersed tube tunnel - linking Hong Kong to Macau and the mainland Chinese city of Zhuhai. The design included two artificial Islands to serve as the transition structures for the tunnel to bridges, entailing a massive seaborne land reclamation project, and the use of thousands of sheet piles, and man-hours. The challenges of driving individual steel sheet in 100? of water are well known, let alone in the open waters of the South China Sea. In 2010 a joint effort between American Piledriving Equipment (APE) and Allnamics Pile Testing Experts convinced the Chinese contractor First Harbor Marine Group China that a massive multi-vibro hammer can be used to drive 130? long, 72? diameter steel pipe piles weighing 662 US tons each into the sea bed of the South China Sea for the Hong Kong - Zhuhai - Macau bridge artificial islands. Combining APE?s hammer design, production and operation know-how with the pile driving simulation and installation know-how of Allnamics made it possible to show the feasibility of driving these gigantic piles into bottom of the sea to the required depth.

By David White

"When finished (projected completion in 2016) the Hong Kong-Zhuhai-Macau Bridge Project will comprise three cable-stayed span bridges and a 4.15 mile immersed tube tunnel - linking Hong Kong to Macau and the mainland Chinese city of Zhuhai. The design included two artificial Islands to serve as the transition structures for the tunnel to bridges, entailing a massive seaborne land reclamation project, and the use of thousands of sheet piles, and man-hours. The challenges of driving individual steel sheet in 100’ of water are well known, let alone in the open waters of the South China Sea.In 2010 a joint effort between American Piledriving Equipment (APE) and Allnamics Pile Testing Experts convinced the Chinese contractor First Harbor Marine Group China that a massive multi-vibro hammer can be used to drive 130’ long, 72’ diameter steel pipe piles weighing 662 US tons each into the sea bed of the South China Sea for the Hong Kong - Zhuhai - Macau bridge artificial islands. Combining APE’s hammer design, production and operation know-how with the pile driving simulation and installation know-how of Allnamics made it possible to show the feasibility of driving these gigantic piles into bottom of the sea to the required depth.INTRODUCTIONThe challenges of driving individual steel sheets in deep water are well known, let alone in the open waters of the South China Sea. Often the challenges of construction are overcome with engineering or equipment. The challenges of China’s Hong Kong-Zhuhai-Macau Bridge, on the drawing board since 1983, were to overcome both. The challenges of overcoming the skepticism of the Chinese Engineering community would be another story.The finished project will comprise three cablestayed span bridges and a 4.15 mile immersed tube tunnel linking Hong Kong on an eastern span to the China mainland cities of Zhuhai and Macau via two western spans."

Jan 1, 2017

By Maria Flessas, Justin Ray, Danielle Steinmetz, Brian Zuckerman

"The Ventura County Medical Center Hospital Replacement Wing project consists of the construction of a 2- to 3-story building with a basement encompassing the entire footprint and two corridors connecting the new hospital wing to existing buildings. The site is located in the Ventura Basin where strong ground shaking has been observed during moderate to large earthquakes on nearby faults. The upper 90 feet of the soil consists of loose to medium dense finegrained sands and low plasticity silts that are potentially susceptible to liquefaction, seismic densification, and hydroconsolidation. Ground settlement associated with a large seismic event on a nearby fault is estimated at 20 to 26 inches. To account for the anticipated ground settlement, auger pressure grouted (APG) piles gaining support below the potentially liquefiable soil were selected for the support of the proposed structure. Challenges for pile design included the anticipated earthquake-induced ground settlement, high downdrag loads, low soil lateral capacity during strong ground shaking, and the effect of pile installation on the performance of the existing adjacent buildings and the installed shoring system. The replacement hospital is supported on over 600 APG piles, with lengths varying between 120 and 140 feet. Axial pile capacities were verified with an extensive indicator pile installation program and dynamic pile load testing.INTRODUCTIONThe Hospital Replacement Wing (HRW) project is at the Ventura County Medical Center (VCMC) in Ventura County, Southern California (Figure 1). The VCMC consists of three interconnected hospital buildings (Buildings 303, 304, and Fainer Building), the Medical Laboratory/Cafeteria Building, two mental health buildings, a medical office building, an emergency generator building, and surface parking lots. The HRW is near the center of the campus, adjacent to several existing buildings.The HRW is a 2- to 3-story structure, with a 15- to 20-foot-deep basement beneath the entire 95,000-square-foot building footprint. The HRW project includes a Loading Dock, a four-level corridor to the Fainer Building (Fainer connector), and a two-level corridor to the Medical Laboratory/Cafeteria Building (Café connector). The corridors are structurally separated from the existing buildings. Typical dead plus live load column loads for the HRW range from about 635 kips to 935 kips and total loads range from about 860 kips to 1,295 kips."

Jan 1, 2016