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By S. Chilka, I. Maloney, J. Brady

"The purpose of this project was to design the Electrical Service Platform (ESP) for the Cape Wind Offshore Wind Farm. The ESP structure comprises two primary parts: the topside platform housing the electrical equipment and the two jacket substructures providing foundation support to the platform. The topside is supported only by the two inner legs of each jacket. The site water depth is relatively shallow and the seabed comprised of loose sediment subject to severe local scour up to 18 feet. The piles are designed for local scour, storm conditions, vessel impact, ice loads and pile installation fatigue. This paper focuses on the design and construction aspect of this project.PROJECT DESCRIPTIONBackgroundThe Cape Wind project will be located in Nantucket Sound between Cape Cod on the Massachusetts mainland (northeastern coast of the USA) and the Islands of Martha’s Vineyard and Nantucket (Fig. 1). The project is to be sited on Horseshoe Shoal, about equal distances from the mainland and the two islands. The project will produce 75% of the electricity used on Cape Cod and the Islands of Martha’s Vineyard and Nantucket with zero pollution emissions and resulting in the reduced operations, fuel consumption and pollution emissions from the fossil fuel power plants in the region. The wind farm, if constructed per plan, is expected to be America’s first offshore wind farm.The wind farm will consist of an array of 130 Siemens 3.6-megawatt offshore wind turbines with a combined production capacity of 468-megawatts. The offshore wind turbine towers will be bolted onto the transition pieces supported by monopile foundations driven into seabed. The power from the 130 wind turbine generators will be delivered to the Electrical Service Platform (ESP) by an array of up to 14 seabed conductors."

Jan 1, 2017

By Peter A. Thompson, Richard E. Prust

"The Bangkok Mass Rapid Transit (MRT} Chaleom Ratchamongkhon Line project is the first underground subway to be completed in Thailand. It consists of 22 km (14 miles) of twin-bored tunnels and 18 cut and cover stations constructed within the deltaic deposits that underlie the city. This paper describes the ground conditions, site investigation, including the use of the self-boring pressuremeter and the associated design issues for the construction of deep foundations. The paper also describes a selection of the various deep foundation solutions that were adopted to address particular constraints of the project and the ground conditions, including slurry walls for the cut and cover stations and foundations used for the underpinning of existing structures.INTRODUCTIONThe MRT Chaloem Ratchamongkhon Line Mass Transit Underground Railway comprises approximately 22 km (14 miles) of tunnels and 18 stations. The route is shown in Figure 1.The project was divided into two design and build contracts. The northern section was awarded to the ION joint venture, composed of Italian-Thai Development PLC, Obayashi Corporation and Nishimatsu Construction Co Ltd. Arup were contracted by ION for the design of the northern section. The section comprises 11 km (7 miles) of twin-bored tunnels, nine cut and cover station tunnels constructed within perimeter slurry walls using top down construction methods, and two cut and cover tunnel structures.The majority of the route of the northern contract follows existing highway Rights of Way. This results in the tunnel alignment passing through the foundations of existing highway bridge structures for which a variety of deep foundation solutions were adopted to underpin these structures.An 8-story park and ride building in the Lat Phrao area was also constructed using deep foundations."

Jan 1, 2005

By Jinung Do, Sung-Ryul Kim, Juhyung Lee

"Model tests have been performed to investigate the vertical, horizontal and cone tip resistances of bucket pile embedded in sand by different installation methods; suction force by pump and jacking force by actuator. Micro-cone penetrometer is used to evaluate the variation of the effective stress inside and outside of the pile after installation. As a result of vertical pull-out test, the jacked pile shows 3 times larger resistance than the suction-installed pile. For horizontal pull-out test, the ultimate horizontal capacity and the slope of load-displacement curve on the suction-installed pile decreases by 22% and 40%, respectively, compared to the jacked pile. In cone penetration test, inside cone tip resistance of the suction-installed pile is about 40% smaller than the jacked pile, which indicates that the effective stress is reduced due to upward seepage of bucket pile in sand by suction force. Therefore, installation methods can affect the behavior of the bucket pile significantly.INTRODUCTIONA suction force occurred when bucket pile penetrates into sandy soils induces seepage flow into the bucket pile so downward seepage near the outside of bucket pile causes to increases the effective stress, while upward seepage inside the bucket pile decreases the effective stress (Mahn, 2005; Fig. 1). The effect of induced seepage causes to reduce the penetration resistance during installation. On the other hand, reduced effective stress can decrease the horizontal and vertical capacities of bucket pile by significant disturbance at the tip of the bucket pile due to the flow net. Due to the complexity and difficulty considering the effects of suction installation, many previous researchers generally have neglected the effect of suction installation in their experiments. Therefore in this study, the effects of suction installation on resistance of bucket pile is examined."

Jan 1, 2016

By Raymond Henn

Yes we have also used some however, again because of the nature of the maintenance window where we have that two hour (at best) window every night and due to the numerous other crews that are wanting to get in to do the other types of maintenance activities, we don't know if we are going to be getting into that same area from one night to the next. So even with the dormancy additives that one can add to cementitious grouts (that are good up to 72 hours) we don't know if we are going to get back in to the same locations from one week to the next. That's why I use the term "the forgiving nature of the acrylamide". It allows us to ream out the hole allowing us to use the exact same hole without having to re-drill a new hole. The program started in 1997 and we have a budget between labor/materials and equipment of 4.5 million dollars on a year to year basis. For the next few years that is going to come down drastically because the program is going to be more of an ongoing maintenance program. The program started in 1997 and we have a budget between labor/materials and equipment of 4.5 million dollars on a year to year basis. For the next few years that is going to come down drastically because the program is going to be more of an ongoing maintenance program. Up to the end of 2001 we were just over 1.7 million liters of between AV100 and AV118 grout. Of that, approximately just under 200,000 was AV100 and the remaining balance was AV118.

Feb 10, 2003

By Christian L. Escalera

Over seven years ago, on October 29, 2012, Superstorm Sandy pummeled the Northeast of the United States inflicting heavy damage on New York City Transit’s (NYCT) system. Since then, NYCT has been methodically rehabilitating and hardening its assets to upgrade service and prevent future impacts caused by similar devasting storm surges. Part of these resiliency efforts, NYCT’s 207th St Yard Project is one of many projects that make up the Sandy Repair and Flood Mitigation Program. The work to be performed on the 207th Street Project includes building a perimeter Floodwall along the Harlem River, extending up 215th Street and 9th Avenue with the intent of having the ability to withstand a 500 Year Storm flooding event. The original 1,535 lineal feet of the marine side floodwall design consisted of 937 each W40x235 H-Piles continuously welded to PS 27.5 flat sheet to form an interlocked and composite steel seawall that would protect the NYCT 207th Yard from a storm surge of the Harlem River. However, after the Contract was awarded and a Notice to Proceed was issued, Walsh Construction Company II (WCCII) partnered with Mueser Rutledge Consulting Engineers (MRCE) to propose a redesign of the marine wall section as a Value Engineering Change Proposal (VECP). This VEP redesign is comprised of 279 each 54in Diameter Steel Pipe Piles that are interconnected with continuously welded PZ 35 sheet piles interlocks. The intent of the VEP was to provide a cost savings that could be shared by both parties as well as alleviate some constructability and alignment control concerns that WCCII had expressed to NYCT. The VEP allowed WCCII to substantially lower the total cost which was shared between NYCT and WCCII.

By Paul Summers, Kevin Richardson, Willem (Billy) Villet, Paul J. Sabatini, Edward C. Clukey

"Between 2008 and 2009, more than 6,000, 23-m long deep mixing method (DMM) elements were constructed to support 124 concrete mats comprising the foundations for the process trains for an LNG facility. The Owner requested first-of-its-kind analyses and assessments to confirm the quality and reliability of the DMM foundation. This paper provides information on these assessments and the procedures used to ultimately conclude that a fit-for-purpose foundation system was constructed.During early phases of construction, several DMM test cores revealed nodules of unmixed clay in upper core samples. A comprehensive review of available DMM core information was undertaken. It was concluded that the amount of coring being conducted as part of the contractor’s QA/QC program should be increased to achieve a foundation system with the required level of reliability.Three-dimensional finite element analyses were completed considering various distributions of defects in the DMM elements and the effects of potential downdrag on DMM elements. Calculated mat settlements and mat stresses were compared to cases without defects in the DMM elements. Various distributions of loaded and unloaded mat areas and number and position (both in the subsurface and laterally) of defects were considered. Four (of the 124) mats were identified as potentially “at-risk”. The settlement performance of these mats is currently being monitored and, to date, performance has been acceptable.IntroductionThe foundation support system for the process train at a major LNG facility comprises more than 6,000, 23-m long DMM elements. The general subsurface stratigraphy at the project site comprises (from the ground surface): (i) up to 8 m of fill sand initially placed underwater building to a stable construction platform; (ii) up to 12 m of soft organic clay (Unit II clay); and (iii) clayey sand and sand layers becoming progressively denser with depth (Unit III sands). Each DMM element comprised two secant 1.5-m diameter DMM columns. DMM elements were typically arranged as cells enclosing one, two, or three DMM elements."

Jan 1, 2017

By Jim Bruce, Naresh Gurpersaud

"The West Toronto Diamond project, under construction since 2006 and due to be complete in 2015, is a rail-to-rail grade separation project in the heart of urban Toronto. Once complete, a depressed corridor over 1000 metres long will take the CN tracks beneath the CPR tracks. An interlocking steel pile wall serves to retain ground and cut off groundwater. Remedial measures, constructed using jet grouting, were required at several locations within and behind the steel piles.At mechanical interlock joints damaged or suspected of being damaged, jet grouting was used to improve native soils on the retained side of the wall to reduce permeability of the soil mass in intimate contact with the joints to 10-7 cm/s. At a number of steel piles where groundwater and soil type combined to cause basal instability inside the pipes during the interim between excavation and concreting, jet grouting was used to construct temporary bottom seals. At locations near adjacent structures where the steel pile installation process resulted in disturbed ground on the retained side of the wall, jet grouting was used to strengthen and stabilize ground.This paper outlines the details of the various jet grouting applications, the respective testing programs implemented to demonstrate in situ permeability and strength of the soil-grout matrix, and performance of the constructed system.INTRODUCTIONThe West Toronto Diamond (WTD) is a junction of several railway lines, all intersecting at the same grade (Figure 1). A major grade separation project at this site commenced in 2006 and is scheduled to be completed in 2015. The whole of the work is comprised of multiple contracts, completed and/or ongoing, by different constructors. Once completed, a depressed corridor over 1000 metres long with over 23,500 m2 (face area) of retained earth will bring the CN tracks beneath the CPR tracks and eliminate a major bottleneck at the most heavily used rail crossing in Canada."

Jan 1, 2017

By Alberto Carmona Rosell, Sri Ram Ramankutty

"The installation of Bored Piles and Diaphragm Wall under slurry using tremie raises quality concerns on the integrity of concrete. It is vital to understand the effects on concrete integrity during concrete pouring process. This paper intends to unveil to what extent the compressive strength of the concrete pour is affected in contact with drilling fluid still. Another important angle of analysis proves whether the inclusion of solids particles of un-hydrated fluid could have impact on the concrete compressive strength. The testing comparing the response of concrete compressive strength when drilling fluid is included into the concrete mix altering the water/cement ratio by 5%, 20% and 30%. Comparative results are analysed between two different hydrated slurries namely sodium activated Bentonite and 3rd generation synthetic polymer.1. INTRODUCTIONSoil stabilization is the base for a successful deep foundation execution. The G3 System Slurry developed by Ground Engineering Operations (GEO), with its third generation polymer, namely PolyMud®, is an innovative and unique alternative to the mineral based slurries for soil stabilization, enhancing the quality and integrity of the underground foundation structures. It optimises the production rate of work progress and cost as well. At the same time, PolyMud® slurry is proven to be environmentally friendly.Guaranteeing the maximum quality of the foundation elements according to the initial design is one of the most important objectives and a concern for the foundations contractors. In order to fulfil the project expectations in this aspect, any incident that could compromise the designed concrete integrity and capacity must be avoided.GEO, has carry out its own research regarding effects on the concrete compression results if drilling fluid intermixes with fresh concrete while pouring. To shed light in this regard, GEO, in collaboration with CML (Concrete Materials Laboratory) Sdn. Bhd., carried out empiric tests that analyse this particular event from different perspectives, bringing up the corresponding results that will be studied and commented in this article."

Jan 1, 2015

By Wolfgang G. Brunner

Mai- Liao, in Yun Lin province of Taiwan, which was once a remote area on the coast of the South China Sea, has been developed into an offshore industrial complex. Approximately 100 million m3 of imported sand fill were used to reclaim the site from the sea with an overall area of almost 3.000 hectares. Land reclamation started in March 1994 and was completed at the end of 1998. A total of 41 industrial plants were constructed on the site, including an oil refinery, a naphta cracking plant, a cogeneration plant, a coal- fired power station, a heavy machinery plant, a boiler making plant, water purification plant, several petrochemical plants and a new harbour. From 1998 onwards, new plants were taken into operation in uninterrupted succession. The main purpose of the ground improvement by vibro- displacement, used predominantly to form the foundations of the oil storage tanks , was to reduce the liquefaction potential of the subsoil during earthquakes. The top layer across the site was treated by dynamic compaction before the installation of the stone columns. Heavy structures such as chimney- stacks and buildings were constructed on pre- cast concrete piles driven by diesel hammer. The earthquake design criteria specified an earthquake magnitude M = 7.3 and an acceleration a = 0.21 g. Stone columns were installed by the dry bottom feed process, which was controlled by an automatic monitoring system, to depths ranging from 13 to 20 m to provide flexible tank foundations. Installation of 1.500.000 linear m of stone columns commenced at the beginning of 1997 and was completed in August 2000. 60 % of the stone columns, in particular the deep ones, have been carried out by Bauer vibrators. The Chi- Chi earthquake ( M = 7.3 ) took place on 21 September 1999 and was followed by Cha- I earthquake ( M = 6.8 ) on 22 October 1999. A survey carried out after these earthquakes showed very positive results. The maximum observed settlement was 10 mm and none of the tanks suffered any damage.

Jan 1, 2002

By Daiki Takano, Naoki Takahashi, Hidenori Takahashi, Ikuo Towhata, Yoshiyuki Morikawa

"The method in this study, in which cement-treated piles are installed into the ground to decrease the amount of liquefied lateral flow, has been studied. The authors are also investigating the most effective arrangement of piles to optimize cost-effectiveness. In their investigation, they propose shifting the position of the piles to prevent lateral flow in various directions. The present study conducted centrifuge model tests to clarify the improvement effect of piles against the lateral flow of liquefied soil and the effect of the pile arrangement. Then, numerical fluid analyses were conducted to consider the improvement mechanism. As a result, the model tests and numerical analyses showed that the pile improvement dramatically reduced the lateral displacement and that the average total flow velocity decreased in the irregular case.INTRODUCTIONLiquefied ground subjected to seismic motion loses its stiffness and strength, and lateral flow often occurs in sloping areas and backfill areas behind collapsed quay walls. In the Hyogoken–Nanbu Earthquake in 1995, the reclaimed island that was surrounded by collapsed quay walls expanded toward the sea and the amount of displacement reached a few metres (Hamada et al., 1996). Two countermeasures can be considered to guard against lateral flow: preventing liquefaction and reducing lateral displacement. The former method is ideal; however it is costly and time-consuming. Based on these considerations, the authors (Takahashi et al., 2013; Morikawa et al., 2014) are currently studying a method in which cement-treated piles are installed into the ground (see Fig. 1) to decrease the amount of liquefied lateral flow. The countermeasure cost using this method is relatively low because of the low replacement ratio. The authors are also investigating the most effective arrangement of piles to optimize cost-effectiveness. It has been proposed that the position of the piles should be shifted so that lateral flow can be prevented in various directions, as described in Fig. 2."

Jan 1, 2015

By Peter Deming

"PART 1 OF 2INTRODUCTIONSlurry trenches are the least cost hydraulic barrier available, if the excavated spoils can be recycled into backfill. As such, slurry trenches are constructed where possible, sometimes at high risk. Slurry trenches are also used to install biopolymer drainage trenches, which have a low safety factor because the biopolymer slurry weight is marginally greater than the weight of water. In marginal ground the construction risk falls to both the Owner who designs and asks for the construction, and the Contractor who manages the work and promises to complete the project successfully. This paper discusses design and construction of slurry trench barriers in marginally stable ground and where groundwater chemistry invokes the need for slurry management details to obtain proper backfill placement.As a designer, Mueser Rutledge Consulting Engineers works for both Owners and Contractors. We are usually able to convince Owners of their responsibility for design detailing in order to obtain a working final product and to obtain reasonable bids from Contractors by disclosing construction needs and designing to reduce the contractor’s exposure. We often work for Contractors to produce designs which result in successful construction in projects where the Owner’s engineer places the responsibility of design and construction on the Contractor.This paper is intended to inform both Owner and Contractor audiences of resources which are available to reduce the risks of trench collapse in difficult ground conditions. We hope it serves this purpose.DESIGNSubsurface InvestigationsSubsurface conditions should be defined by borings focused on definition of the soil profile and soil design parameters. After general subsurface conditions are defined, barrier borings should be drilled along the final alignment.Definition of Soil Strength and CompactnessCompactness of sand and gravel strata should be defined with Standard Penetration Test N-values. The shear strength of cohesive materials should be defined by laboratory testing. Silt and fine sand strata with little cohesion should be investigated using mud rotary techniques to prevent disturbance. General strength characterization by soil layer should be used for analysis of trench wall stability."

Jan 1, 2006

By Alice Arana, David M. Cacoilo, Joel L. Volterra

"To make space for the new South Ferry Station in lower Manhattan, engineers and contractors carved out a new tunnel beneath three operating subway tunnels and tangentially to yet another tunnel. Creating the space required the design and construction of complex temporary excavation support and underpinning systems and the design and installation of real-time monitoring systems. Construction for the new station and tunnel was mainly cut-and cover in a mixed-face area of soil and rock approximately 2,000 linear ft long, 60 ft wide and up to 70 ft deep. Close coordination between the design/build team and the project owner, the Metropolitan Transportation Authority (MTA), was critical.With the construction of this $400 million project, the MTA and New York City Transit (NYCT) are correcting the numerous physical and operational deficiencies of the existing station and improving the lives of millions of commuters. Built in 1905, the original South Ferry Station is on the IRT Broadway–Seventh Avenue Line of the New York City Subway and is the southern terminal of the #1 subway service, which forms a loop to return uptown. The station has a sharply curved single platform on the outside of the outer track of a two track loop. This platform is short and does not allow the rear five cars of a normal 10-car subway train to load or unload. In addition, once the train stops at the station, commuters wait while retractable floor grates bridge the gap created between the platform and the subway car doors, and then they have only one exit from the station. Spray nozzles keep the tracks lubricated to reduce the train wheels’ friction caused by the tight curve. The sharp curvature of the loop and the inability to use half of the subway car doors slow train operation. With the new ADA-accessible station, 10-car trains will be able to open all doors, and additional entrances, escalators and elevators will greatly reduce travel times."

Jan 1, 2008

By Rimas Veitas, James Panton, Erich Steinlechner

"Ductile Iron Piles (DIPs) are a proven, viable alternative to conventional piles, and for the past five years have been successfully used throughout New England. The installation process of DIPs lends itself to both large and small projects. Because of their installation efficiency they provide a substantial cost savings over drilled micro piles. Several New England projects (both end bearing and friction) will be evaluated, focusing on the installation and design procedures.BackgroundThe driven ductile cast iron pile (DIP) is a simple, fast and highly effective pile system. Over the last 30 years over 10 million feet of this pile system has been installed worldwide predominantly in Europe. DIPs are a prefabricated driven pile system utilizing high strength ductile iron pipes which are manufactured using a spun-cast process having outside diameters of 4 5/8” and 6 5/8 inches. The standard pile lengths are 16.4 feet long. The pipes are manufactured with a tapered socket with an internal shoulder for full engagement at the top and a tapered spigot at the bottom. The individual pile sections can be connected with this Plug and Drive® connection to drive a pile of any length.(see figure 1)The DIP system’s inherent advantage is the simplicity of the installation process. The piles are driven to refusal or to a required penetration depth with the use of a high-impact highfrequency hydraulic hammer (ie. Breaker hammer). In most applications the hydraulic hammer is mounted on an appropriately sized excavator (see Photo 2). At the completion of driving the pile, the pile is cut off (see photo 5) and the remaining section of pile is fitted with the appropriate driving shoe and serves as the lead section for the next pile. Being able to reuse the cut off section, yields minimal if any pile shaft waste. The pile is then fitted with an appropriate pile cap plate to receive the load from the superstructure."

Jan 1, 2017

By Yoshinori Kurumada, Tatsuo Nagatsu, Keiji Uchida

"Cement deep mixing method has been utilized in the process of construction of an underwater tunnel in Singapore. The soil was improved by this method to prevent undesirable heaving of the soil below the excavated area. Quality control experiments approved the effectiveness of CDM method in increasing the strength of the soil and prevention of undesired heave of the ground. The process of the construction of this project and the quality control experiments results are discussed in this paper.INTRODUCTIONThe Marina Coastal Expressway is a 5.3 km long underwater highway tunnel with five lanes in each direction. It mostly comprises a twin box culvert structure (53.3 m exterior width and 10.89 m height) and was opened by the Land Transport Authority of Singapore (LTA).The contract zone C485 was the most challenging area of the construction; it involved a 700 m long underwater tunnel of which 400 m was built beneath the seabed at the mouth of the Singapore River. A double steel pipe sheet pile wall was built as a temporary cofferdam to keep water out of the excavation site, and the cut-and-cover method was used for excavation. In order to ensure a sufficient cross-sectional area for the flow of the Singapore River, the construction was divided into two phases focused on the left bank (Stage 1) and right bank (Stage 2).The Cement Deep Mixing (CDM) method was used to improve the ground, which comprised soft marine clay, to ensure safety during the excavation. The efficiency of this method in increasing the soil’s strength was approved previously. The design standard strength was quck = 800 kPa. Based on the study conducted after the construction, the average the Unconfined Compression Strength (UCS) of the soil stabilized by the CDM method was quf =3,000 kPa. This paper discusses the effect of the CDM soil improvement construction on the reduced displacement from the excavation and the quality control of the soil improvement."

Jan 1, 2015

By Wayne S. Smith, Erik James, Jose R. Gomez

"Soil mixed seepage cutoff walls are increasingly being used in levee and dam modification projects nationwide. An important aspect of their overall quality depends greatly on the language included in the specifications. Depending on the method (e.g. vertical axis auger mixing, cutter soil mixing, or trench mixing techniques) the specifications are a blend of prescriptive and performance based contract language with differences in element construction, element connections, quality control/quality assurance, and work area restrictions. Many of the existing specifications were initially developed by contractors in whole or in part, and can contain restrictive provisions favoring the authoring contractor. In response to these challenges, basic soil mixing fundamentals were revisited and recent lessons learned incorporated, resulting in the development of a new specification for soil mixed seepage cutoff walls that provides adaptability for the various construction methods. The new specification addresses quality control, quality assurance, equipment independence (elimination of restrictive contract language), rig instrumentation.INTRODUCTIONSoil mixing has been used in the construction of seepage barriers for over 30 years. Most soil mixed project primarily use the wet-rotary-shaft, wet-rotary-end or wet-vertical panel methods (reference FHWA Deem Mixing Manual Figure 137). One of the first major soil mixing seepage barriers was constructed in the Jackson Dam in Wyoming. Since then the use of soil mixing for seepage barriers has increased significantly and this specialized domain of construction which was solely procured by RFP methods, is now increasingly being specified in projects issued for bid. The Bid documents require more careful specification writing than RFP methods because the RFP methods allowed detailed proposals by the contractor. Therefore the development of soil mixing specifications began with contractors preparing the specifications. This paper addressed some of these issues, and proposes methods to address these resulting concerns. The resolution of these issues considers several aspects: 1) Assessment of binder injection, 2) Evaluation of mixing index, and 3) Verification testing."

Jan 1, 2016

By Gerald Verbeek

There are certain concepts that seem to invite responses from some, including some in the foundation industry and even some within DFI, that are at best surprising. Business owners and their employees share the desire that their company does well and continues to operate. Maybe company growth is not always realistic but maintaining the current level of activity is in the least what they hope for. In other words, they hope that their company is sustainable, and they are fully behind that notion. But when the concept of sustainability is raised, there is, at least with some, suddenly doubt that that is a good thing. And yet, that concept only aims to achieve at a grander scale what the owners and employees desire for their company. There are many definitions of the term sustainability, but probably the most commonly used description is that framed by the United Nations in 1987. It states that sustainability is the concept of meeting the needs of the present without compromising the ability of future generations to meet their own needs. Arguably that definition is too abstract and does not provide the type of specific goals and targets we are used to. To help with that, to some extent, in 2015 the United Nations formulated 17 Sustainable Development Goals (SDGs), to provide "a shared blueprint for peace and prosperity for people and the planet, now and into the future." And undoubtedly those SDGs are fodder for those that question the concept of sustainability in the foundation industry. How can our industry, they wonder, ensure that there is no poverty or hunger (SDG 1 and 2), and the climate action goal (SDG 13) immediately leads to the hot button topic of global warming. And maybe this is where advocates lose (some of) the sceptics of the sustainability concept, but hopefully they will continue to read this article that lays out why sustainability simply makes sense, also for the foundation industry and especially for DFI.

Nov 1, 2022

By M. Hesham El Naggar, Tony Sangiuliano, Alper Turan

"Bridge abutments supported on pile foundations are often constructed over weak and compressible soils. The consolidation settlements induced by the embankment loads are known to result in downdrag and lateral forces on the piles supporting the bridge abutments. The performance of a pile group including inclined piles embedded in consolidating soils was investigated numerically considering surcharge loads from approach embankment construction. A two-dimensional numerical model was constructed using commercial finite element software PLAXIS and calibrated against field measurements of the abutment movements observed on Brookdale Avenue Underpass Structure located on the Macdonald-Cartier Freeway in Ontario between Cornwall and the Quebec border. The soft soil model (SSM) was used to simulate the constitutive behavior of the compressible soil deposit. The SSM model parameters were determined based on the laboratory tests. Subsequently, time dependant development of downdrag effects was comparatively evaluated for vertical and inclined single piles as well as a pile group that included both vertical and inclined piles.Results showed that drag loads increased with the consolidation time. However, majority of accumulation of drag loads took place within first 120 days after installation of piles. The results also indicated that the shear forces and bending moments are controlled by the lateral spreading of foundation soil and their accumulation is proportional to consolidation time. The large axial strains caused by large downdrag forces are considered to have yielded the piles and this is a possible reason for unusual abutment movements. The results presented in this study are considered to be of interest to researchers and practitioners.1. IntroductionDeep foundation units are widely used for supporting bridge piers and abutments, where weaker surficial soils preclude shallow foundations. Particularly in Ontario, semi-integral and integral abutment bridges are typically supported on end-bearing steel driven piles. The construction of approach embankments over weaker, compressible soils results in significant vertical and lateral soil movements, which induce additional loads on piles supporting the abutments. In order to minimize such effects, preloading and surcharging are commonly employed approaches to avoid unanticipated settlements prior to the installation of piles. Other alternatives such as aggregate pier supported approach embankment are also being studied as the schedule restrictions imposed by preloading and surcharging becomes cost prohibitive (Turan et al. 2012)."

Jan 1, 2015

By A. C. Galvis-Castro, R. Salgado, M. Prezzi, E. Ganju, R. D. Tovar-Valencia

It is generally accepted that the unit shaft resistance of piles in sands is lower for tensile loading than for compressive loading. So far, very little attention has been paid to the influence of the installation method on the tensile-to-compressive unit shaft resistance ratio. The objective of this paper is to analyze the effect of installation method on the ratio of unit shaft resistance in tension to that in compression for a model pile installed in a dense silica sand. To study installation effects, load tests on model piles were carried out in a half-cylindrical calibration chamber with digital image correlation (DIC) capability. The model piles were either jacked in one stroke using a constant rate of advance, or pre-installed into the dense sand samples. Digital images of the model pile and sand were taken during the load test and processed using DIC to obtain the displacement field in the sand. It was found that unit shaft resistance was essentially the same in tension and compression for the pre-installed pile, however for the jacked pile, the unit shaft resistance in tension was approximately half of that in compression. DIC analysis revealed that: (1) during the load test, more displacement occurs in the soil domain for the pre-installed pile compared to the jacked pile, (2) for the jacked pile, the magnitude of displacement in the soil domain is greater in tension than in compression and (3) for the pre-installed pile, the magnitudes of displacement in tension and compression are similar. INTRODUCTION Pile foundations can be categorized into two main types depending on the method of installation: displacement piles (e.g., jacked or driven piles) and non-displacement piles (e.g., bored piles or drilled shafts) (Basu et al. 2010; Salgado 2008). The response of these piles to loading can be studied in the laboratory by means of calibration chamber experiments on model piles that are either jacked into the samples, representing displacement piles (Jardine et al. 2005; Lee et al. 2011; Tovar-Valencia et al. 2018), or pre-installed in the sand sample, representing non-displacement piles(Galvis-Castro et al. 2019a; Le Kouby et al. 2013; Tehrani et al. 2016)

Jan 1, 2019

By Juan M. Pestana-Nascimento, Robert G. Bea, Hamed Hamedifar, Emery M. Roe

The current State-of-the-Practice is grounded heavily on deterministic characterization and assessment of the performance of civil engineering infrastructure. In particular, flood defense systems, such as levees, have been evaluated within the context of the Factor-of-Safety where the computed capacity of the system is compared with the code specified demand forces. Uncertainties associated with the capacity and demand forces render deterministic modeling incomplete. In particular, two structures with the same Factor of Safety can have vastly different probabilities of failure. While efforts have been made to assess levee vulnerability, results from traditional engineering approaches omit important factors because they do not account for uncertainties included in analytical modeling, and natural variabilities, or human and organization factors. This paper utilizes risk assessment methods to advance methods for quantifying the contribution of uncertainties to engineering analyses, and thereby provide additional information to help assess sustainability of geotechnically engineered systems. The probability of failure of a geotechnically engineered system is directly impacted by how well the system is understood, and how uncertainties are incorporated in development of understanding of the system. This paper presents methods to evaluate two types of uncertainties for three potential failure modes of flood protection levees: underseepage, slope (or levee) instability, and overtopping/erosion. These analyses account for two types of uncertainty: 1) Type I – inherent uncertainty, 2) Type II – analytical modeling uncertainty. Human and organizational task performance and information development and utilization uncertainties are not included in these analyses. This paper focuses on the behavior of the flood protection levee system for Sherman Island, a western island in California’s Delta. Sherman Island is of critical importance to California because of the very important infrastructure systems that pass under, on, over, and adjacent to Sherman Island, including: natural gas pipelines, regional and interregional electricity transmission lines and telecommunication facilities, two deepwater shipping channels; and State Highway 160, a link between major transportation expressways. The work evaluates current (year 2010) and future conditions (year 2100) and incorporates variations in capacity and demand arising from projected human response activities and global climate change.

Jan 1, 2017

By Alan Christopherson

Nearshore construction projects often require installation of steel piles and specific methodologies of installing piles may adversely affect nearby species of concern. Water is an uncompressible medium which allows for easy transmission of energy through the water column. Energy transmission through water depends on the following factors for pile driving: 1) direct contact of the pile and the water; 2) the depth of the water column; 3) the size of the pile; 4) type of hammer; and 5) the energy of the hammer. Seasonal restrictions are usually the best practicable alternative for reducing habitat impacts when pile driving activities may adversely affect the species of concern. When seasonal restrictions are not practical other options need to be evaluated, including mitigation and noise attenuation devices. The broad array of mitigation options will not be discussed as part of this presentation but instead will focus on noise attenuation technologies. Dewatered cofferdams can be effective noise attenuators as they eliminate direct contact of the pile with water while driving. Also, introduction of a compressible medium, like air, near the energy source can provide sound energy attenuation. An unconfined bubble curtain is relatively inexpensive but is not effective in tidal marine projects or rivers and may have unacceptable secondary effects. Secondary effects must be evaluated as these can increase exponentially for larger projects. Secondary effects to the environment include air quality degradation from air compressor use, transportation costs for fuel and equipment, and the potential for injecting oily compressed air into the water column. The confined bubble curtain works well in nearly all environments. It usually is more expensive initially, relative to an unconfined air curtain, but there is less potential for harmful secondary effects. Generally, seasonal restrictions will be adequate to protect species of concern. However, there are conditions in which mitigation or one of the sound attenuation options should be utilized. Site specific factors, including the amount of energy being imparted into the environment, sensitivity of the species of concern, current, accessibility, length of time needed to complete the project, and the cost of the sound attenuation, should be factored into the permit evaluation.

Jan 1, 2013