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By Tian Miaomiao, Cheng Yin, Shen Jun, Yu Hao, Li Yafei

Vast amounts of waste drilling mud containing heavy metals is produced during oil drilling process, which causes great pollution to the environment. Therefore, it needs to be treated until it is harmless. This study uses industrial waste and Portland Cement stabilized waste drilling mud; the unconfined compression strength, leaching amount of Pb2+ and Cr6+ ions, and pore size of the stabilized soil were tested at different times during freezing-thawing cycles. The antifreeze performance of the stabilized drilling mud with industrial waste is discussed. The results show that the strength of the stabilized soil decreases with an increase in the number of freeze–thaw cycles. The strength loss of the stabilized soil after freeze–thaw cycles can be effectively reduced by increasing the industrial waste content, especially the content of phosphogypsum in the stabilizer component. Pb2+ ions and Cr6+ ions can be effectively stabilized by industrial waste. The results of the pores test prove that the compactness of stabilized soil solidified by industrial waste residue is greater than that of cement alone.

Nov 1, 2022

By Chu E. Ho, Alfredas Daugiala, Nicola Ebanks

"The construction of an ancillary structure for the new Second Avenue Subway Line in Manhattan, New York City involved a deep excavation in highly variable rock conditions adjacent to a fragile masonry building. The maximum difference between the lowest and highest rock elevations was about 30 feet, which posed a problem for the installation of secant piles that formed the supporting retaining wall for the excavation. At certain areas, the rock levels were higher than the top of the invert slab of the ancillary structure. To avoid disturbance to the adjacent fragile building, the secant piles were fully cased for drilling through the overburden soils and the rock sockets were formed using non-vibratory technique. This paper discusses the design and installation details of the secant pile wall and the contingency measures that were considered to mitigate the highly variable rock conditions. Monitoring of the adjacent fragile building showed that impact of pile installation were controlled within tolerable limits and safety of the building was not compromised.INTRODUCTIONThe 96th Street Station forms part of the newly constructed Second Avenue Subway Line on the East side of Manhattan Island, New York City (Figure 1). During construction of this station, several deep excavations were carried out adjacent to existing fragile buildings (Arksman et al. 2012, Grigson et al. 2016). These fragile buildings were typically four to five stories high, with a single rubble wall basement supported on timber piles or seated directly on the fill. The timber piles were often found to be in a poor condition and connections to the footings were compromised due to rotting of the timber within the zone of water table fluctuation. Several of these fragile buildings had to be strengthened and underpinned to improve the stability of the structures prior to commencement of excavation for the new subway station box (Trabold et al. 2012, Ho and Pena-Iguaran, 2013). The situation was most challenging at Ancillary Buildings 1 and 2 located at 93rd and 97th Street respectively, where secant pile walls were located merely 2 feet away from the adjacent property line, due to architectural space constraints. While mitigation of excavation induced ground movements can be controlled by the adoption of a stiff excavation support system, a more concerning factor was the uncertainty associated with the impact of the secant pile wall installation on the stability of the existing fragile buildings. This was particularly difficult at Ancillary 1 where the secant piles encountered highly variable rock levels that intruded into the excavation space. The following sections discuss the design and installation of the secant pile wall and contingency measures that were considered at Ancillary 1."

Jan 1, 2016

By Kim Chan, Bryn Thomas, Ben Dening

"Increased rail capacity is required into Kooragang Coal Terminal near Newcastle, NSW, Australia to relieve rail traffic congestion and improve management of train arrivals. An additional arrivals track is proposed on new embankment within a heavily constrained site located between existing railway tracks, a high pressure gas pipeline located 7m beyond the toe of the embankment and an environmentally sensitive wetland area. Ground conditions at the site consist of deep soft estuarine clays, a soil profile which is consistently encountered throughout this part of the east coast of Australia. Upon determining that a ground improvement solution was required to ensure global embankment stability, various solutions were considered including a piled viaduct, retaining walls, dry deep soil mix (DSM) columns and concrete injected columns (CICs). DSM columns were adopted as the design solution, a decision which was driven by the presence of sensitive infrastructure and a confined site. DSM offered further advantages including reduced impacts on temporary working platform design, where the use of a thinner platform could be justified owing to the lower track loads of a DSM rig relative to other ground improvement techniques.INTRODUCTIONThis paper presents a case study of the design of DSM ground improvement works to provide support for and enable safe construction of a new railway embankment over deep soft soils with a number of nearby infrastructure and other constraints. The project site is approximately 1km long and is constrained by existing railway tracks, a high pressure gas pipeline and a wetland area of ecological significance. Due to the site constraints and ground conditions, a number of ground improvement techniques were considered during the design process, with DSM columns eventually adopted. This paper discusses the design development and the particular suitability of the technique for use in this application.SITE DESCRIPTIONLandformThe site is located along the northern boundary of the Kooragang Coal Terminal (KCT) at Kooragang Island (KI), a collection of former islands located near the mouth of the Hunter River, north of Newcastle, NSW. The topography of the original area was generally flat with mudflats, swamps and mangroves existing along tidal water courses. Subsequent dredged fill reclamation and development has amalgamated the previous islands into the current KI. The site area extends over numerous channel infills including the buried former course of the Moschetto Channel (paleochannel).Figure 1 shows the proposed 1km long new rail corridor construction area in relation to the various natural and man-made site constraints including existing tracks, the high pressure gas pipeline, the wetland area and the existing reclaimed area."

Jan 1, 2015

By James P. Chivilo, Gregory R. Meeder, Scott J. DiFiore, Matthew H. Johnson

New construction in metropolitan areas has direct impacts on immediate neighbors and abutters. While noise and dust are generally nuisance concerns, demolition, vibrations, excavation, and dewatering can cause structural damage to adjacent structures. Different cities, states, or jurisdictions have different regulations that dictate requirements, roles, or responsibilities for varying parties during construction. The authors will introduce and discuss risks of new construction adjacent to existing structures, and the legal framework in Illinois which requires the owner of the new construction project to provide adequate protections for adjacent existing structures. The authors, who are engineers and attorneys, will discuss technical and legal concerns, and will highlight the importance of early and frequent communication among project participants to manage risks, despite whether or not any local regulations exist to drive the process. RISKS IN ADJACENT CONSTRUCTION New construction in metropolitan areas inherently involves some combination of noise, dust, ground-borne vibrations, earth excavation, and subgrade dewatering. These issues have potential to directly and adversely affect abutters and their property. Noise and dust can be nuisance concerns, while vibrations, excavation, and dewatering can result in damage to abutters’ structures. Noise and dust are unlikely to lead to physical damage to abutters’ property, and can be controlled with limited work hours and good housekeeping practices. Vibrations and excavations, however, if not well understood, planned for, and mitigated, can result in serious damage to abutters’ structures. In turn, this damage introduces additional and often significant costs and schedule delays.

Jan 1, 2019

By Sina Z. Yekta, Zhangwei Ning, Pierre Frappin

This paper describes a DC (direct current) electrical resistivity method, which uses the contrasts in resistivity measurements to estimate the diameter of jet grouted columns as soon as they have been completed, with varying depth and water table, and without excavation. The measurement procedure is illustrated by several examples of application sites, including the Grand Paris tunneling works during the last 3 years where the method was systematically recommended in quality control for jet grouting works.

Sep 8, 2021

By Aaron Evans, Chu E. Ho, Tom Richards

"This paper describes an innovative case history of using jet grouting to form a groundwater cutoff wall at the interface of a cut-and-cover construction and an existing tunnel. The design of the jet grouting layout was complicated by the presence of a left-in-place bulkhead of unknown dimensions abandoned by previous construction of the existing tunnel. Jet grouting was performed through predrilled holes within the narrow space between the existing bulkhead sheeting and tunnel structure. A systematic sequence of primary and secondary jet grout elements of varying diameters and panel lengths was executed to achieve an effective groundwater barrier. A key challenge in the jet grout design was the impact of potential deviations due to shadowing effects of the left-in-place bulkhead sheeting and pre-formed jet grout columns, as well as overbreak concrete in adjacent secant pile walls. The flexibility of the jet grouting methodology enabled a wide range of operational parameter combinations to be performed, allowing column diameters to be adjusted based on actual field installation measurements. Special precaution was exercised when grouting at critical locations to avoid over-pressurization and damage to the existing tunnel structure.IntroductionThe 96th Street Station box for the new Second Avenue Subway Line in Manhattan, New York included a transition tunnel, which connected the station to an existing tunnel built in the early 1970s (Figure 1). The new station and transition tunnel were both constructed using the cut-and-cover technique with bottom-up sequence (Aksman et al. 2012, Grigson et al. 2016). The main station structure incorporated permanent diaphragm walls for most of its length, except for the southern segment where high rock levels were encountered and the station box was constructed within temporary secant pile walls socketed into the rock. The permanent diaphragm walls were also utilized for temporary excavation support (Ho and Hu 2014). At the northern end of the site, the new transition tunnel was constructed within temporary secant pile walls that extended from the station diaphragm walls to the existing tunnel at the tie-in location. A temporary traffic deck spanning 60ft across the secant pile and diaphragm walls along the full excavated length of the site allowed traffic to continue operating at street level while construction of the station and transition tunnel progressed below grade."

Jan 1, 2016

By Robert Thurner, Albin Norrman, Sami U. Raja

The West Link is a double track railway project currently under construction in Gothenburg, Sweden. The project includes the construction of 8 kms of track, 6 kms of which will be in tunnels. Beside several large excavations, three new stations will be built: Centralen, Haga and Korsvägen, all within the city of Gothenburg. The first construction phase of the project began in May 2018, and the finalization of the project is expected in 2026. The project is divided into five sections. Keller is involved in four of these contracts since the design & planning phase in 2018 assisting the special foundation works with various geotechnical techniques including Dry deep soil mixing (DDSM), jet grouting, rock grouting, uplift piles, sheet piling and rock dowels. The core idea behind successful collaboration has been to apply the right product for a location specific challenge which can help optimise costs & time for the project with a minimal environmental impact. Due to the extensive nature of the project, a team of experts from various locations around the world is helping design and execute various foundation technologies and providing solutions to the practical challenges in the project like working close to existing structures, rail lines, river etc.

May 1, 2022

By Anjana C. P, K. Ranga Swamy

The hilly regions of Kerala are severely affected by excess rainfall, causing tremendous damage due to landslides and slope failures. It is necessary to strengthen the existing slope profiles to prevent such disasters and avoid their risk to human lives and civil infrastructures. This paper studies the effect of micro pile to reinforce the slopes in Idukki district of Kerala, where slope failures are frequent. Three-dimensional slope stability analysis is carried out on slopes from the Idukki to obtain safety factor values using the MIDAS GTS NX program. The slope is fully saturated herein by taking the model's piezometric surface at the ground level to simulate high rainfall intensity. The critical slopes are then modelled with micro piles to analyze their effectiveness in improving the stability under static conditions. Different micro pile arrangements are considered, and a series of slope stability analyses have been carried out to obtain the optimum configuration with the required safety factor. The FOS values increased by more than 50% with micro piles for all the slopes. The optimum micro pile arrangement obtained for each slope shows that micro pile distribution between the toe and middle of the slope is an effective location for reinforcing slopes.

Sep 1, 2022

By Hamed Layssi, Farid Moradi, Thomas Tingson

This paper describes the feasibility and pilot study of of using existing non-destructive testing solutions for evaluating structural integrity and mechanical performance of mass concrete foundations. This paper includes two pilot studies using well-known NDT methods (i.e., Crosshole Sonic Logging and seismic tomography) for new applications (i.e., NDT inspection of mass concrete foundations). In the first case, we will examine an existing mass concrete foundation block with internal cracking, which has negatively impacted the strength and stiffness of the foundation block. A combination of pulse velocity and 2D tomography was used to evaluate the structural integrity in the foundation block. In the second case, the quality and integrity of newly built mass foundations were evaluated using Crosshole Sonic Logging (CSL). The methods are combined to locate potential sub-surface defects such as large voids and discontinuities. This paper aims to study the effectiveness of the NDT methods of Deep Foundations to assess the quality and structural integrity of new and existing mass foundations and explore the opportunity to extend the capabilities of these tests beyond their conventional use.

Sep 8, 2021

By Andrew Middleton, Mick Stadter, Chris Crowe, David Chong

"The Level Crossing Removal Project – Package 1 is part of the Victorian Governments commitment to remove 50 of the most dangerous and congested level crossings across Melbourne. This involved removing three crossings on the Frankston Line in the south east suburbs of Melbourne. The works involved replacing approximately 2.5km of at grade track with three rail cuttings up to 8 m deep at each of the bridges that replace the level crossings. The cuttings are retained by piled retaining walls and during the main construction occupation approximately 250,000 cubic metres of soil was removed. The project has presented significant geotechnical challenges due to the location in residential suburbs and tight rail corridor and rail occupation timeframe. These challenges included temporary and permanent wall stability, foundations, earthworks and dewatering. As a result, careful design and innovative construction techniques have been necessary to limit impacts on the community and meet the project timeline.INTRODUCTIONThe Level Crossing Removal Project – Package 1 is part of the Victorian Governments commitment to remove 50 of the most dangerous and congested level crossings across Melbourne. This involved removing three crossings on the Frankston Line where it crosses North Road in Ormond, McKinnon Road in McKinnon and Centre Road in Bentleigh.The project involved replacing approximately 2.5km of at grade track with three rail cuttings up to 8 m deep at each of the bridges that replace the level crossings. The cuttings will accommodate three lines of rail tracks with the cuttings up to 25 m wide. The cuttings are retained by piled retaining walls and during the main construction occupation approximately 250,000 cubic metres of soil has been removed.The project presented significant challenges due to the location in residential suburbs and tight rail corridor and rail occupation timeframe. As a result, careful design and innovative construction techniques have been necessary to limit impacts on the community. The geotechnical challenges generally fell into one of three areas, earthworks, structures and groundwater. The primary earthworks challenge for the project was moving the 250,000 cubic metres of soil in a 10 day window, however, from a geotechnical viewpoint, obtaining a stable subgrade on which to operate the necessary construction plant in a short time frame with constrained site access and time to import materials was the key. Whilst closely watching the performance of the dewatering system, a range of contingency plans were developed to cope with any difficulties."

Jan 1, 1900

By Eleonora Di Mario, Colin B. Turnbull, Matthew G. Mills, Chengbin Miao, Wilhelm S. Degen

"In the past decade, the ‘zero-dredge’ philosophy has become the preferred option for the formation of marine seawalls and reclamations, compared to the partially or fully dredged options, as this solution presents several environmental advantages. Recent relevant project experience is presented herein in order to highlight key design principles and construction issues central to the successful construction and performance of a sloping rubble seawall founded on soft soil improved by stone columns. If designed and installed with proper quality control, correct treatment intensity and sensible construction staging, stone columns are a safe and cost effective method for seawall foundations. This paper provides guidelines with regards to the design, construction and quality control for the correct implementation of stone columns as a foundation element for sloping rubble marine seawalls.INTRODUCTIONBenefits of sloping marine seawalls founded on stone columnsTo suit the current environmental requirements in Hong Kong, recent projects are tending to favour zero-dredge solutions, such as the Hong Kong Boundary Crossing Facility and the forthcoming Three-Runway System. The installation of stone columns allows the underlying deposits, generally consisting of very soft to soft clay and silt (soft soil), to improve in strength to the extent that the seawall can be directly placed on the seabed. This negates the need to dredge the soft soil and, therefore, this ground improvement technique represents an ideal solution for zero-dredge projects.Stone columns can also provide several other beneficial effects, including: accelerated drainage, reduced settlement, increased slope stability and soil reinforcement in the event of an earthquake. Stone columns, in contrast to competing cementitious methods, are a very ductile foundation method. This ductile behaviour is part of the design concept of stone columns in soft soil. Past projects located in Hong Kong and elsewhere, with an improved soft soil layer thickness of over 15m, have shown that stone columns can remain fully functional in terms of both drainage and horizontal reinforcement, even after settlements of over 3m and lateral displacements of up to 1m have occurred."

Jan 1, 2017

By Anahita Modiriasari, Benjamin S. Rivers

Measurement while drilling (MWD) is a subsurface exploration technique associated with real-time and continuous monitoring and recording of drilling data during the drilling process. This technique can be used for underground investigations to differentiate ground strata, detect the presence of fractures and voids, and evaluate geological features and mechanical properties of geomaterial. When MWD is used for geotechnical investigations, it can improve site characterization, identify variable conditions, improve design and construction, lead to shorter project delivery times, reduce the cost and risks associated with limited subsurface data and geotechnical uncertainties, and maximum return-on-investment. Given these benefits, MWD is gaining attention among transportation agencies and the geotechnical industry. Federal Highway Administration’s (FHWA’s) innovation deployment program “Every Day Counts (EDC-5)” includes the implementation of Advanced Geotechnical Methods in Exploration (A-GaME), which aims to implement effective, underutilized subsurface exploration methods, including MWD, in U.S. practice. This paper provides an overview of the MWD technology for geotechnical site investigations and presents a case history where MWD was employed to design deep foundation for the construction of a building in Massachusetts. The advantages of this technology for risk reduction and project cost and time saving are also discussed.

Oct 1, 2022

By Teresa M. Bodas Freitas, Arianna Lupattelli, Peter J. Bourne-Webb, Diana Salciarini, Martina Zito, Donatella Sterpi

The thermomechanical response of thermally-activated (TA) piles under monotonic thermal loads is quite well understood and the remaining uncertainties relate to the effect of long-term, cyclic loading of individual TA piles and pile groups. Recent studies undertaken by the authors have provided insights into the behaviour of TA pile foundations undergoing cyclic thermal loading. Despite their simplicity, the analyses show that key aspects of the observed response of piles in sand, under cyclic thermal loading can be reproduced, providing confidence in the outcomes of the analyses. The studies examined isolated piles and pile groups, and concluded that irrecoverable thermally-induced settlement may be mitigated through the choice of an appropriate margin of safety on the pile shaft resistance under service mechanical load conditions, and the maximum thermal stress can also be readily estimated. This paper consolidates these works and provides guidance regarding the safe geotechnical and structural design of the piles, then looks towards the remaining issues around the safe provision of thermally-activated pile foundations.

May 1, 2022

By Steve Davidow, Ashely E. Evans, Peter M. Kandaris

"Annually thousands of deep foundations are constructed across North America supporting high voltage transmission line structures. However, a recent state of the practice survey by the Deep Foundation Institutes’ Electric Power Systems Foundation Working Group discovered that the electric power utility industry lacks consistent foundation design guidelines. The survey identified a wide variability in design assumptions, a minimal understanding of risk based analysis, and a need to standardize design methodologies. This paper summarizes the state of practice in electric system foundation design and proposes a framework for risk-based foundation design by accounting for uncertainty from both loads and resistances. Loads derived from electric system codes do not necessarily provide a compatible level of reliability for the design of foundations, as they are a mixture of probabilistic and deterministic values. Load uncertainty is derived from variability in weather conditions, structural models and material properties, typically accounted for by code derived overload factors. Resistance uncertainty arises from variability in natural soil properties, resistance models, subsurface construction techniques, material sampling methods, and limited observations. A consistent methodology is offered relating nominal resistance capacity (strength) to structure loads and service state criteria. Discussion also includes the need for risk-based assessments to account for non-structure load influences (fluvial loads, scour ground loss, liquefaction, etc.).INTRODUCTIONNearly 40 years ago the Electric Power Research Institute (EPRI) embarked on a major research effort to optimize reliability and economics of transmission line foundation design. Strategies focused on improvements in design models, site characterization, exploration strategies and testing to reduce uncertainty and variance in analysis. Transmission line engineers realized that safety and reliability advancements in design based on probabilistic approaches, with a focus on the unique nature of transmission line, could better control risk and cost.Some transmission line professionals took full advantage of these advancements, particularly where research led to improved software and models. Yet, even after two decades of extensive research, by 1995 the industry still had made little progress in changing design habits. The majority of designers were still characterizing sites via deterministic methods, using loads that may or may not relate to a consistent probability of occurrence, and applying a traditional global factor of safety approach (Phoon, et al. 1995). The following two decades have seen even greater developments in software and reliability-based analysis methods, but old habits seem to die hard as recent surveys show less than half of design professional quantitatively assess risk in their design process."

Jan 1, 2017

By Challa Venkata Rami Reddy, Anindya Roy, G. R. Konni

This paper presents the results of pile lateral capacities obtained from both conventional design and fullscale pile lateral load tests. Conventional design using P-Y curve analysis is very commonly being used by designers; designers use well accepted software programs like Lpile and Allpile for analysis. However, these programs do not cover the soil models to simulate engineering behavior of marine carbonate sands; which generally have different engineering behavior than silica/quarts sands. In this study, the existing soil models for common sands have been used to assess pile lateral capacities and these results are compared with the results from full-scale instrumented pile lateral load tests performed in compacted marine carbonate sand fills of artificial island constructed for oil and gas facilities in Abu Dhabi. The objective of this study was to verify the applicability of the existing sand soil models for carbonate sands and also to verify the associated conservatism in the pile lateral capacities. This study shows that the actual pile lateral response is much stiffer than what was anticipated through the LPile analysis. Therefore, further research focus may be required to capture the engineering behavior of the marine carbonate sands to develop specific P-Y curves.

Sep 8, 2021

By Craig M. Shillaber, Joseph E. Dove, James K. Mitchell

"This paper addresses two primary factors affecting the sustainability of Deep Mixing Methods (DMMs): construction materials and handling of the spoil from wet mixing methods. We examine these factors within a life-cycle embodied energy (EE) and carbon dioxide (CO2) emissions accounting framework, using the LPV 111 project in New Orleans, LA as a case history. The underlying assumption is that project planning and preliminary design have determined that a DMM is the best ground improvement alternative for achieving the broader aims of sustainable development. While EE and CO2 emissions are direct measurements of environmental impact alone, we illustrate how their minimization can also influence the social and economic consequences of the project. It is recommended that DMMs use lower energy and carbon material alternatives to Portland cement and lime in the binder whenever possible, with preference given to locally sourced materials. Currently available alternative cementitious materials include fly ash and slag, which are waste products from other processes. In addition, recycling the spoil material from wet mix methods on site is recommended. If the material cannot be recycled on site, transporting it to a processing and recycling center for later use as fill is preferred over landfilling. INTRODUCTIONWithin the geotechnical community there is an increased appreciation for sustainability considerations, which are an important component of the planning, design, construction, operation and maintenance of projects. An assessment of project sustainability includes holistic life cycle thinking, systems analysis, environmental impact assessment, use of safe and benign materials, awareness of local societies and cultures, social equity, protecting human health and well-being, and monetary costs (Abraham, 2006). Since ground improvement is a principal practice domain of geotechnical engineers, it is important that geo-professionals play a role in addressing the sustainability for these projects. In this paper, we illustrate by case history how different materials and methods associated with deep mixing projects can impact overall project sustainability through quantifying project embodied energy (EE) and carbon dioxide (CO2) emissions. EE is defined as all energy consumed to bring something into its present state (Chau et al., 2008; Inui et al., 2011; Soga et al., 2011; Chau et al., 2012). Recommendations are then made for how adverse environmental impacts of Deep Mixing Methods (DMMs) may be minimized, leading to more sustainable geotechnical construction."

Jan 1, 2015

By Arjan Jovani, Arjan Beqiraj, Përparim Alikaj, Altin Karriqi

"Koman dam is one of most important high dams in Drin River Cascade. Safety of these dam is very important not only in power production but also in social and environmental aspects connected with vital activity of local people living in downstream of Drini River and in economic development of the country. In December 2014, during the rehabilitation works on some protection measures at the downstream dam toe, a considerable amount of water leakage emerged from the dam toe. This was noticed even before, but its amount and physical-chemical properties were not evaluated. In order to study the origin and flow direction of this water leakage, KESH sh.a. (Albanian Power Corporation) realized Geophysical and Hydro chemical surveys, turbidity and flow measurements and respective analyses of them. Geophysical survey consist in Apparent Resistivity surveys and Self Potential survey. The survey was done in 3 lines using Resistivity “Real Section” technique. Results are plotted in Sections and plan maps of resistivity and SP parameter. There are defined possible leakage areas and the main flow directions are defined. Also, there is done a hydro chemical analyse. Nine water samples were taken from the different places as Komani lake, service galleries of dam, dam toe and two karst springs which were analysed for both physical-chemical parameters and isotopic composition of O-18 and D. The attained analytical data found that water from the dam toe leakages shows the same chemical signature and isotopic composition of O-18 and D as the water from the lake, thus confirming the hydraulic connection between them.Also, There is done the analyse of water leakage turbidity and amount of this leakage"

Jan 1, 2016

By Thomas Hyatt, Brandon Phetteplace, Camilo Alvarez

A test pile program was undertaken at a project site in Ain Sukhna, Egypt for an import/export oil jetty. Two 1219 mm diameter open ended steel pipe piles were evaluated at two separate test locations. Each test pile was dynamically tested during initial drive utilizing a Pile Driving Analyzer (PDA). Restrike testing was also performed to evaluate the time dependent soil setup. One static compression test and one static tension test was performed at each test location. A correlation of the static and dynamic load test results was established to develop a driving criteria for the piling across the two kilometer project. The constructability benefits of shorter piles will be discussed in more detail, given that the pile lengths were shortened by 9 to 10 meters on average. Lastly, the use of a four pile linear layout to perform both compression and tension tests will be covered. INTRODUCTION With the increased number of Very Large Crude Carriers (VLCC) & Ultra Large Crude Carriers (ULCC) being used to transport oil products around the world, companies and/or nations are presented with the challenge of transferring these products to and from the carriers in deep water scenarios, typically 15 to 20 meter depths, to accommodate the vessels draft. One option for loading/unloading the oil products from a VLCC or ULCC would be to transfer to/from smaller vessels several miles offshore, whereas the most economical option is to unload directly to a pipeline via a berth/jetty platform near shore. These berth platforms must be designed to withstand multiple loading scenarios while these carriers are moored and transferring their products. The use of Large Diameter Open Ended Pipes (LDOEP) piles are a common foundation choice for this offshore application. One of the drawbacks of LDOEP piles, especially across a large project site, is that there can be extreme variability in the pile driving behavior. This can be caused by either a change in soil conditions or the performance of the soil plug. Due to this variability, it is important to verify throughout the duration of the project that the piling is being installed to the correct criteria as established during the load test program. A well designed driven pile load test program, preferably with the combination of Static Load Testing (SLT) and Pile Driving Analysis (PDA), should develop a driving criteria that can allow the contractor and owner to monitor any change in driving behavior.

Jan 1, 2019

By Jason Buenker, Molly Winston

Torque-installed piles are gaining popularity in Southern California as the go-to deep foundation element for small- to medium-capacity loads in urban environments. The torque-installed pile is a displacement- based screwed pipe pile with a closed-end conical tip welded to the bottom of the pipe. Torque-installed piles are most efficient in loose to medium dense soils with high liquefaction potential. Where used properly, torque-installed piles can be installed faster, require less clean-up, and create less onsite vibration/disturbance than other pile alternatives. However, torque-installed piles are not applicable in all soil conditions and care must be used to apply the pile effectively in the correct subsurface environment. This paper will review current Southern California state-of-the-practice for torque-installed pile design and construction, potential roadblocks to successful installation, and available capacities from load tests. INTRODUCTION Torque-installed piles are a type of full-displacement screwed pipe pile originally developed in Southern California circa 2001 by Substructure Support, Inc. The pile is unique for its proprietary closed-end conical tip shown in Fig. 1. The tip has a welded steel-helix plate and cutter teeth that allow the pile to be advanced efficiently under applied torque and down pressure (crowd). Since original development of the pile, several contractors or manufacturers have proposed similar proprietary screw-type piles with comparable conical tips. Pile installation is relatively quiet, vibration-free, does not generate spoils, and faster than comparable pile types. The pile was originally developed as an alternative to driven pile foundations and remains a critical substitute to driven foundations in urban environments. Torque-installed piles are conventionally specified as 12 ¾-inch outside diameter (OD) steel pipes with a ⅜-inch-thick wall, although larger sizes with alternative dimensions have been used outside Southern California. Pile installation lengths generally range from 30 to 50 feet but may reach 80 feet or greater where soil conditions permit. The pile is generally backfilled with concrete following installation to increase lateral pile stiffness and may incorporate rebar cages or other reinforcing steel to facilitate connections to structural elements. The pile is frequently specified using performance-based specifications that encourage contractor innovation and use of proprietary installation means and methods.

Jan 1, 2019

By Mohab Sabry, Emre Biringen

"Over the past decades, there has been an increasing recognition of the strategic use of pile-supported rafts in design of heavily-loaded structures to reduce total and differential settlements. However, such a hybrid foundation construction method has not been widely utilized in many countries, including the U.S., due to code limitations. In current practice, the foundation design is based on either (i) the bearing capacity of the raft supported by the subgrade soils, or (ii) solely the pile capacity. This paper addresses the potential use of such hybrid piled-raft systems, where the structural load is shared by both by the piles and the subgrade soils directly beneath the raft, in foundation design of power plant structures. The study assessed some of the characteristics of piled-raft behavior by undertaking three-dimensional finite element analyses of two raft sizes, and various pile layout patterns, including the rafts with piles distributed evenly and only in the central area of the raft. The computer software PLAXIS 3D with the Mohr-Coulomb constitutive soil model was used to facilitate the modeling of such cases. The results presented in this paper indicate how strategically locating the piles could reduce the differential and total settlements.INTRODUCTIONUnder the high applied loads coming from the superstructure, the addition of piles is primarily required to improve the factor of safety against failure when a raft does not provide adequate bearing capacity. If the bearing capacity of the raft is sufficient to carry the total load with a reasonable safety margin, then the addition of piles is usually intended to reduce the settlements to an acceptable amount. In current practice, the design process for pile-supported raft foundations conservatively concentrates on providing solely the pile capacity to carry the total structural load without taking the contribution of the raft into account. This paper addresses the potential use of hybrid piled-rafts in controlling foundation settlement of power plant structures by considering the support of both the piles and the subgrade soils beneath the raft to carry the load."

Jan 1, 2017