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By Peter Middendorp, David J. Tara, Gerald E. Verbeek, Jan Fischer

"For pile driving simulation the model used must be accurate for the entire process, i.e. from the start of pile driving until the pile has reached its target depth. Of the various model components (hammer, pile and soil), the soil is the most difficult to characterize accurately. This is well known, but the aspect that is not as well understood (and therefore commonly misapplied) is the fact that the soil properties and thus the soil parameters do not remain constant during the pile driving process. Furthermore, this phenomenon of soil fatigue, mainly for skin friction, as a continual change of soil resistance during pile installation, is not implemented into all commonly applied pile driving simulation software and could therefore not be taken into consideration. In this paper the effect of soil fatigue will be described by numerous research results, showing that this effect will occur regardless. Different methods to consider the change of soil resistance during pile installation will be presented, some applying soil fatigue while others merely reduce soil resistances. Using currently available wave equation software that can take soil fatigue into consideration, the importance of doing so will be shown on the basis of the back calculation of a monopile installed offshore in Germany.THEORY BEHIND SOIL FATIGUESkin friction and toe resistanceTo simulate pile installation as accurately as possible, detailed geotechnical knowledge about the mechanical behavior of the soil surrounding the pile is necessary during each step of the installation process. Therefore, to ensure ""geo-mechanical correctness"" of a pile driving simulation, the shaft friction and the toe resistance have to be recalculated at each penetration level. For the skin friction parameters this is especially important since they change significantly during pile installation because of soil fatigue. Depending on the pile and soil type, the toe resistance can experience changes as well due to soil fatigue during to pile driving. However, in this paper the toe resistance values were kept constant over the entire penetration depth.In general, the unit skin friction can be derived from measured values (CPT, qs) or calculated as a function of the horizontal effective stresses dh acting perpendicular to the pile wall of a vertically driven pile. The horizontal stresses can then be converted into the unit skin friction qs using the Mohr-Coulomb failure criterion:"

Jan 1, 2017

By Michael Arnold, Robert Bachus, Michael Bracher, Jamey Rosen, Robert Roff

"For a high hazard USACE facility, the Center Hill Dam in Tennessee, several disparate streams of data were compiled into a single geospatial and relational enterprise data management system to store, analyze, visualize and distribute the data collected during installation of a deep cutoff wall. These data streams included historical drawings and pre-construction plans and grouting records; geological data from boreholes; attributes of barrier wall elements; element verticality data analyzed from multiple measurement methods; and concrete field and laboratory analytical data. A previously developed data management system developed by the authors, WallTracker, was extensively modified to also include manually collected and real-time measurements from several types of dam monitoring instruments. The system now uses enterprise database technologies with Geographical Information Systems capabilities to manage and relate these data streams into a common platform and allows access to the raw and interpreted data via web and desktop-based interactive tools, including interactive map and cross-sectional viewers and other graphical and tabular reporting tools. One of the primary benefits of this system is the neartransparent interaction that is possible with the Nashville District of USACE on the project. These techniques can now be effectively incorporated into systems that address the unique construction and data management tracking requirements for dams, dikes, and levees.IntroductionThe Center Hill Dam rehabilitation, as with other deep foundation installations, requires the contractor to collect a substantial amount of information over the course of the project, both for internal quality control of construction progress and methods, and for demonstrating compliance with owner specifications. This paper discusses techniques used at Center Hill Dam for consolidating, visualizing and analyzing construction and instrumentation data using relational database and Geographic Information Systems (GIS) technology, collectively referred to as an Information Management System (IMS).The remainder of this paper presents the needs and objectives of the IMS, the components and data flows involved, the capabilities and user interfaces of the systems, and the benefits for the end users."

Jan 1, 2017

By Paolo Cavalcoli, Federico Pagliacci, Marco Chiarabelli

"The Sheikh Jaber Al-Ahmad Causeway Project in Kuwait is estimated at approximately $US3.7 billion and consists of constructing a causeway across the Kuwait Bay, connecting the Shuwaikh Port with the northern Subiyah area, where the new “Silk City” will be established. The $US77 billion Silk City will revive the ancient “Silk Road” trade route and will become a major free trade zone linking central Asia with Europe. The new city will be completed in 2030, it will house about 700,000 people and, furthermore, it will include the tallest tower in the world. The Causeway will stretch approximately 23.3 miles and will be composed of a combination of low-level bridges, embankments and transition islands. A bridge of about 16.8 miles in length will span the navigation channel and a free flow interchange at the Shuwaikh Port will connect the causeway to the main road network in Kuwait City. The geo-construction portion of the project involves the execution of 1,200 drilled shafts with diameters of 98 inches and 118 inches embedded to a maximum depth of about 276 feet. Details are provided concerning the subsurface conditions, the geotechnical characteristics and the strength parameters, illustrating, as well, the installation technique implemented for the construction of the drilled shafts. In addition, particular attention is paid to the description of the challenges faced while constructing the drilled shafts at a distance of about 10 miles from the shore, such as the depth of the water above the midline (more than 160 feet), an underwater current and the tidal variation.INTRODUCTIONThis paper presents an overview of the foundation works executed for a 37km causeway across the Bay of Kuwait, connecting Shuwaikh Port with Subiyah New Town Development. The project, in which Trevi is actively engaged, includes a 27 km low-level bridge across the bay, a main bridge with a span of 200 m, an overpass and a 5 km approach road onshore in Subiyah.The main purpose of this report is to provide information about the nature and features of the applied technique of bored piles, including a description of each work phase and other related details, in order to aid in the design of the foundations for the proposed construction.Works for the soil investigation were carried out in accordance with accepted geotechnical standards/guidelines. Brief descriptions of the methodology of the field are also provided in this report."

Jan 1, 2016

By Peter Florian

At 5:50 am on October 1, 1992, the new $800 million Pittsburgh International Airport Midfield Terminal opened its gates to the world after five years of construction and more than 24 years of planning. Despite numerous design changes, this massive project was completed on time and substantially within budget. The importance of this airport to Allegheny County and the Pittsburgh region was recognized 24 years earlier by Allegheny County Commissioners Tom Foerster and the late Leonard Staisey. Staisey and Foerster established a program to acquire land for the "Airport of the Future".

Jan 1, 1993

By Michael Quadagno

Hudson River Pier 86, home of the historic USS Intrepid Aircraft Carrier and the Intrepid Sea-Air-Space Museum, is currently undergoing a $30M reconstruction. This project involves the demolition of the old timber pile supported pier and construction of a new 150 ft wide by 782 ft long concrete pier, built over the footprint of the old piles. The new pier consists of steel pipe piles, precast concrete pile caps, and a composite deck, made up of precast, prestressed concrete planks and cast-in-place concrete topping. This paper focuses on both the structural design and construction of the new pier, with emphasis on the pile foundation. Pier 86 is unique in that it is required to resist the extremely high lateral loads imposed on it by the permanently moored 898 ft long aircraft carrier during severe storms. A total of 360 steel pipe piles support the new pier. These piles, which are 24 in. in diameter and range in length from 58 ft to 175 ft, were driven down to bedrock. The piles, each having 200 ton allowable capacities, work together to resist the significantly large lateral loads exerted on the pier by the ship. The installation of the piles was unique in that all the piles, including the ?super-longs?, were fabricated to-length offsite, delivered to the site via truck and barge, and installed in one piece, eliminating the need for field splicing. The Pier 86 reconstruction will be completed within an extremely aggressive 18 month schedule, from January 2007 through June 2008. The refurbished aircraft carrier Intrepid will return home in September 2008, and the grand re-opening of the pier will be on Veteran?s Day 2008. This paper provides a case history for owners, government agencies, engineers, and construction professionals that will be faced with the challenges of designing and building new piers.

Jan 1, 2008

By Steven M. Henderson, Zachary D. Jones

The risk of allocation in construction contracts is a primary concern for all parties. For contracts involving subsurface construction the allocation of site condition risk is critical. In the past one hundred years technological advances fundamentally changed how that risk is allocated; yet another shift in this risk allocation may lie just over the horizon due to advances in geotechnical data management. Around the world initiatives are underway to make geotechnical datasets more open and accessible. In the United States some states like Kentucky have already made geotechnical data readily accessible. This proliferation of geotechnical data in the U.S. may impact the allocation of subsurface risk in construction contracts. Many construction contracts contain a differing site condition clause. That clause allows for a modification of the contract price or schedule if the ground conditions encountered by the contractor differ materially from either what was indicated in the contract documents or would be reasonably expected. A contractor, however, is typically not entitled to that modification if the contractor knew or should have known of the adverse conditions encountered. Courts have interpreted the “should have known” language as requiring contractors to make a reasonable site investigation prior to bidding the project. If geotechnical data is available and accessible and reveals the adverse condition the contractor encounters, courts could find that the contractor should have known of the condition and thus will not be entitled to a modification based on the differing site condition clause. Accordingly, the U.S. could be on the threshold of significant shifts in how the risk of differing site conditions is allocated in construction contracts.

Jan 1, 2017

By Amr Sallam, Ahmad Mohamed, Mohamed Alrowaimi

Renewable energy, in the form of wind and solar, has emerged as main source of energy in the modern society. The wind industry has substantially grown over the last two decades to become a key player in providing energy to public. Wind turbines are getting larger, taller, and more efficient every year. The foundation is a major component of the wind turbine system. The wind turbine foundation must provide short and long-term stability for the overall turbine to allow continuous and safe turbine operation for energy production. The turbine serviceability and stability requirements must be geotechnically and structurally satisfied. In North America, major foundation types currently utilized in the wind industry include gravity spread foundation, mono pier foundation, and pile foundation. In this case study, a Post Tensioned Pile Cap (PTPC) foundation was used to support a 3.15-3.4 Megawatt turbine with 125M Rotor supported on 87.5M-hub-height tower. Soil anchors in the form of Auger-Pressure-Grouted-Displacement (APGD) piles and Continuous Flight Auger (CFA) piles were utilized. Four distinct subsoil conditions were identified, and for which four pile designs were adapted. Due to the occasional encounter of stronger soils at 50 to 55 feet (15.2 to 16.7 m), shorter pile design was preferred. To satisfy the design uplift load, pile post grouting were utilized to increase the shaft capacity of the piles. In this paper, the pre-production pile load test program will be described. The pile load test procedure, analysis, and results will be presented. A discussion will be provided, which led to the selection of the optimum pile design to support the high tension loads taking into consideration pile length limitations.

By Jacob Chacko

The Izmit Bay bridge, a 3-km-long suspension bridge crossing of Izmit Bay, Turkey is planned to be constructed in one of the most seismically active places in the world. The site, which has the potential to experience significant earthquakes associated with the relative motion accommodated on the North Anatolian Fault, is underlain by deep deposits of soft soils, and areas of unstable and liquefiable soils. Characterizing the seismotectonic setting, foundation soil conditions, potential fault locations, as well as other geohazards was a critical component for the project concessionaire to finance the project and obtain meaningful bids for bridge design and construction. Given the Build Operate Transfer (BOT) funding mechanism, executing this work in the least possible time was critical to the concessionaire?s financing scheme. Fugro was retained to provide geotechnical, geological, and seismological evaluations for the project region, and to generate data for contractors to develop reliable designs and bids. The uncertainties in these data made it difficult for the BOT concessionaire to finance the project and tender Bridge design and construction. The investment in an early and comprehensive site characterization program to evaluate and quantify those uncertainties allowed the concessionaire to save schedule, provide a robust bid basis to bridge contractors, and persuade banks to finance what was perceived to be a relatively high risk project.

Jan 1, 2011

By M. D. Riegel, P. B. Pizzimenti, E. M. Zamiskie, Britain A. Materek

"The Skanska/Kiewit/ECCO III team (SKE) in association with HNTB was awarded the design-build contract for Phase I of the Kosciuszko Bridge Replacement Project. As lead designer for the SKE team, HNTB was responsible for the design of the Brooklyn Connector which includes construction of approximately 2000 feet of new staged earth-filled embankments utilizing prefabricated modular retaining walls (T-Walls®). The proposed embankments will be constructed adjacent to and beneath the existing Brooklyn Queens Expressway (BQE) viaduct while the existing viaduct remains in service. Critical aspects of the settlement assessment relating to the soils supporting the existing BQE will be addressed, as their behavior drives the deformation of the viaduct. Furthermore, a construction monitoring program was used to enable the designer to assess settlement predictions and allow SKE to mitigate potential impacts to the existing BQE during construction. Additionally, the methodology for installation of the embankments in a limited access area underneath an active viaduct supported on settlement sensitive shallow foundations will be presented.INTRODUCTIONSkanska-Kiewit-ECCO III Joint Venture, in association with HNTB was contracted by the New York State Department of Transportation (NYSDOT) to design and construct the Phase 1 replacement of the Kosciuszko Bridge Design-Build Project. Phase 1 of the project involves the design and construction of the new eastbound structures of Interstate 278 over Newtown Creek from Brooklyn to Queens. The project runs between Morgan Avenue in Brooklyn and the Long Island Expressway Interchange in Queens (approx. 1.1 miles) and includes the staged demolition of the existing structures."

Jan 1, 2016

By Filippo Mira-Cattò, Andrea M. R. Pettinaroli, Elena Rovetto

"The construction of Powisle station of Metro Warsaw Line 2, in Poland, required the execution of two shafts next to an urban road tunnel adjacent to the Vistula River. The shafts were linked by three conventionally mined tunnels to be excavated 10 m below the water table level, into an upper sandy and sandy silty layer and a lower stiff clayey stratum. After a failed dig attempt under the protection of jet grouting and forepoling, it was decided to deal with the tunnels excavation problem by using the ground freezing technique as a temporary, non-polluting geotechnical treatment, keeping in service the upper road tunnel. The planning of the activities and the executive phases had a significant importance for the success of the work. For work scheduling reasons the mixed system was adopted, i.e. using both the liquid nitrogen system and the brine freezing method. The freezing process management, with a real time evaluation of the soil temperature measured by thermometric strings and an accurate monitoring of the overlying road tunnel structure, allowed the tunnel excavation and lining stages to be performed under difficult conditions, without water leaking from the frozen ground shell, within the expected times and saving extra costs.INTRODUCTIONThe new Underground Line 2 in Warsaw connects the eastern and western part of the town. One of the most critical interferences was the under passing of the Vistula river and of the Wislostrada motorway tunnel, a very congested motorway along the western bank of the river, with the construction of the new station Powisle. The construction of the station required the excavation of two shafts, using the top-down system with the creation of intermediate slabs while deepening the excavation.The shafts were used for the extraction of four Tunnel Boring Machines (TBMs), two approaching from the Vistula river side (east-side) and two approaching from downtown (west-side); in order to connect the two shafts was foreseen the realization of three tunnels, two for the underground lines and the central one for the exchanging passenger platform. These tunnels were underpassing the “Wislostrada Road Tunnel” and interfered with this tunnel foundation, which consisted of diaphragm walls (DW), the “barrettes” (Figure 1).Due to the variable geological conditions at the site, the first excavation stage, with a temporary underground support constructed of horizontal jet grouting columns and forepoling, caused the North tunnel face failure, that required an immediate filling of the empty cavities with lean mix concrete under the Wislostrada tunnel slabs. Thereafter, the recovering attempt with the grout injections could not be completed because of the development of heaves induced on the tunnel structures (Bringiotti et al. 2016). In those conditions the tunnel excavation with traditional technologies appeared to be very problematic, with high risk for the structural safety of the Wislostrada tunnel. This would have meant longer duration for the works and higher costs for the General Contractor as well as for the city Council."

Jan 1, 2015

By Chen Xizhe

The caisson is adapted to the foundation of concentrated heavy building. As there are the flowing sand, boulder or cobble and other serious obstruction, the open caisson can't sink, the caisson can solve these problems easily. Especially for the stability of the neighour building, the merit of the caisson is outstanding. Therefore, there are the pier, the foundation of heavy instrument and the large water pumping station etc. using the caisson in China. This paper introduce several caissons and successful experience by author's investigation. It contains the feature and application of the caisson : the examples of caissons such as a huge pier of a bridge acrossing a big river, a large instrument foundation and a large water pump station beside a river; the problem of the design of the caisson and notice items during the caisson construction etc.

Jan 1, 1991

By Denis Huber

The technical assessment of the final works on the "Stéphany Palace" project at Menton in France's Alpes-Maritimes region shows the importance of daily project monitoring based on the observation method recommended by the European standard Eurocode 7 which applies to Foundations and Geotechnical Engineering. Excavation operations to a depth of 10 m near the France-Italy railway track and adjacent buildings required precise observation of land deformations, regular piezometric monitoring as well as special design arrangements. Temporary active tie-rods were thus placed in phases in order to control deformations in the retaining structures resulting from excavation operations. The Menton region, terminating the Alpine arc of mountains, naturally required the consideration of seismic forces in phase in the lower floors of the building, directly linked to the buried walls. These calculations were carried out in accordance with the PS69/92 rules, calling for an increase in dynamic thrust under the effect of gravity field rotation.

Jan 1, 2002

By Bruno Gemmi

A new warehouse built with prefabricated components over an area underlined by soft marine soil deposits started showing differential settlements well before its completion. Its 103 spread footings carrying up to 4,000kN (450t) axial loads had been cast on jet-grouted columns extending and penetrating a layer of sand at a depth of 10m (33ft). Investigations performed to assess the wholeness and consistency of the jet-grouted columns revealed a state of loose jet-grouted masses and uncontrolled, off target migrations of the jet-grouting. Most of the jet-grouting itself was settling. The following remedial solutions were suggested: 1. Construction of new and better controlled jet-grouted columns. 2. Cement-based soil grouting. 3. Expanding resin injections. 4. Minipiles drilled-through the existing footings and reaching into a denser layer of sand existing at 23m below grade. Remedial solution 1. was immediately discarded due to cost and the possibility of a repeating failure in this non-granular and highly compressible soil. Tests of remedial solutions 2. and 3. were carried out. The outcome of the grouting was monitored by Electro Resistivity Tomography (ERT) (Bares et al., 2003), an innovative 3D electro tomography procedure showing where grout had been actually placed and its migrations off target. A successful 4,000kN (450t) load tests confirmed the validity of the solution. Finally, upon the completion of a successful load test, solution 4. was chosen. It supplied the highest degree of reliability thanks to the ease of controlling the final and actual location of the minipiles and to the higher safety factor provided. All remedial work to install the minipiles was eventually performed inside the building. Additional load tests and settlement measurements confirmed the adequacy and success of the chosen solution.

Jan 1, 2011

By Racquel Nottingham, Marc Mastrantuono, Freddy Lopez

In the digital era that we live in, connectivity and mobility play a decisive role in our daily activities. In this context, insufficient telecommunication infrastructure gives origin to the so called “dead zones” (areas with poor or non-existing cell phone reception), which hinder economic development in small communities and in many rural areas, since they remain invisible to a larger marketplace due to the inadequate cellular coverage. Several countries are working to identify these dead zones and with this information, establish strategies together with mobile providers in order to improve the existing mobile networks by expanding the coverage areas. As a result of the analysis, it is expected that thousands of telecommunication towers for 4G and 5G networks will be erected in the coming years. Telecommunication towers are slender elements that require large shallow foundations to verify primarily the safety against overturning. However in remote areas, it can be advisable to consider alternatives to the conventional shallow foundations, in order to optimize the use of materials (concrete, reinforcement steel, etc.). The following article presents an overview of intervention projects, where telecommunication towers were founded on micropiles. The micropiled foundations allowed to reduce considerably the dimensions of the originally planned shallow foundations. Furthermore, the use of micropiles allows for additional optimization, in combination with pre-fabricated foundations (i.e., precast concrete elements, etc.). This paper will focus mainly on the design and the execution of the micropiled foundation.

Sep 8, 2021

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 Guilherme L. M. G. Carvalho, Zachary T. Fleming

In a world of 2-dimensional design documents, envisioning and understanding 3-dimensional interferences for complex foundation construction scenarios can be challenging. Videos and computer models serve as 3-dimensional spatial aids but have drawbacks related to a fixed perspective. Augmented and virtual reality (AR/VR) provide new tools to communicate design challenges and improve construction planning. This paper provides a practical look at the basics of AR/VR systems and the tools available to the foundation design and construction industry by giving a high-level example of the technologies’ use in the design and delivery phases of a complex micropile installation project for the remediation of a dam foundation. Using these technologies, GEI was able to design and deliver a complex foundation remediation solution. AR/VR benefited regulators, and the client, to help understand the design concept, construction sequencing, and approach to overcoming installation challenges. Due to its user-friendly nature and less rigorous programming and hardware requirements, AR proved to be more useful than VR for this scenario. AR/VR will likely not replace videos and computer models; however, it can be a useful 3-dimensional visualization aid that complements the project delivery process and offers benefits that traditional methods cannot. INTRODUCTION Augmented and virtual reality is a promising and rapidly developing technology within the engineering and construction world. Like any rapidly developing new technology, the language describing it can be confusing and dynamic. To eliminate the confusion some definitions must be made. AR/ VR definitions The definitions of virtual reality (VR) and augmented reality (AR) for the purposes of this paper are as follows: VR is a computer-generated immersive environment that the user experiences within a digital 3- dimensional space (Satava, 1993)AR is a composite view created by superimposing digital objects into the user’s real-world view (Azuma, 1997). Often, VR is used in an office environment and allows the user to “visit” the digital site to review site planning, construction sequences, and interference geometry. AR can be utilized in both the office and onsite environments. Like VR, the in-office application for AR is commonly site planning. AR also can be utilized in the field for applications such as seeing through the ground to locate known existing obstructions like utilities, gas tanks, etc.

Jan 1, 2019

By Akhila Manne, Prasad P. V S R

Storage tanks are heavily loaded thin-shelled structures that exert large loads on and require large foundations to support them. They are generally very sensitive to foundation settlements as it may hinder the performance of tanks resulting in significant commercial or social impacts. Selection of their foundation is dependent on availability of suitable ground and limitations imposed by design specifications. Design of the tank foundations is generally based on theoretical methods and validation by representative field tests. This paper reviews settlement criteria for storage tanks as per national and international standards, case studies of large to medium diameter tanks supported on deep foundation i.e., bored cast-in-situ piles and shallow foundations on improved ground and their performance during load tests & hydro-tests is discussed. Paper concludes that storage tanks can also be supported on shallow foundations resting on improved ground reducing the settlement, time and cost significantly depending on the sub-soil.

Nov 1, 2022

By Patrick O. Shires, Harry W. Schnabel

With stable building sites becoming scarce in the greater San Francisco Bay Area, the new Summit Senior Care Facility is being built into the side of an unstable hillside adjacent to the San Ramon Regional Medical Center in San Ramon, California. This hillside has had a long history of instability and the site of the new Senior Care Facility required excavation into both a historic old landslide and a more recent active landslide. After a thorough geotechnical study, it was concluded that the best way to build the new facility would be to construct a tied-back retaining wall in the area of the old landslide, since it extended off-site onto two adjacent properties, and remove the active landslide and replace it with compacted fill before cutting into its toe area with an additional tied-back retaining wall. The design was further complicated by the proximity of the site to several active faults. In the area of the old landslide, the combination of an ascending slope behind the wall, landslide forces and seismic forces resulted in total design pressures between 365 to 4,575 PSF for a wall with a maximum height of 30 feet. The wall for the old landslide was constructed by first drilling and placing steel soldier piles in concrete. The tip of the soldier piles extended a minimum of 12 feet below the landslide plane that was up to 36 feet below the bottom of the wall. Permanent double corrosion protected tiebacks were then installed through the soldier beams and anchored below the slide plane. A shotcrete facing was then installed on the face of the wall. BACKGROUND The site of the Summit Senior Care Facility is located on the southwest flank of Mount Diablo adjacent to San Ramon Valley which is characterized by gently rolling hills. The San Ramon Valley Regional Medical Center, which opened in 1990, is located to the north and an existing church is located to the southwest. There are also private residences located to the southeast. The site is shown in Figure 1. Numerous faults run close to the site, the most significant of which are the Calaveras and Pleasanton faults. The site has also had a long history of slope instability and has been the subject of numerous investigations. Studies conducted in 1979 and 1984 concluded that there was a landslide in the area and recommended that a buttress shear key be constructed between the subject site and the existing church for a sewer main as well as removal and replacement of the head area of the old landslide to stabilize the hospital site. While two previous geotechnical studies in 2008 and 2016 identified slope instability, they did not recognize the genesis and limits of the old landslide on the western portion of the site or the limits of the active landslide on the eastern portion of the site.

Jan 1, 2018

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 Randy R. Williams, Brian W. Wilson, George M. Filz, Marina S. W. Li

"Detailed design of an extensive deep mixing (DM) scheme using the Cutter Soil Mixing (CSM) technique was completed for foundation support of mechanically stabilized earth (MSE) walls for Kitimat Liquefied Natural Gas (LNG) at Bish Cove, British Columbia, Canada. The design was based on the provision of soil-cement structures, constructed in highly variable subsurface conditions that consisted of thick deposits of fine-grained soils overlying granular soils, and required to meet project-specific performance criteria, to support the MSE walls. The design, consisting of rectangular CSM panels constructed to form barrettes connecting to a longitudinal wall of continuous CSM panels, was configured to manage the distribution of stresses and strains that could be developed within the soil-cement structure.The results from 2D finite element analyses were used to determine the necessary arrangement and properties of the CSM panels to accommodate localized areas of relatively high shear, tensile and compressive stresses within the soil-cement structure. The relationships between unconfined compressive strength and elastic modulus for fine-grained and granular soil-cement structures obtained from the Bish Cove data were compared with published references and were found to be significantly different in the higher strength range materials.BACKGROUNDDeep Mixing design was completed for the development of the Kitimat LNG Facility located in Bish Cove, British Columbia, for support of two relatively high MSE walls and associated bulk earthwork operations. Deep mixing was necessary to treat the very weak native deposits in-situ to meet project performance requirements and physical constraints without the need for significant excavation and disposal work. The DM design was undertaken on the basis of adoption of the CSM technique for in-situ ground improvement of the native foundation soils which consisted of very soft to soft fine-grained marine deposits and loose to compact sandy silt to silty sand, overlying dense sand and gravel (Fig. 1). The DM area is located immediately upslope of the Bish Cove beach area, and is “L” shaped in plan, approximately 300 m long by approximately 28.8 m wide (parallel to the beach area) and 165 m long by an average width of 21.0 m (perpendicular to the beach area). The depth of the DM ranged from about 5.0 m to 30.7 m with typically 2.0 m embedment into dense granular soils. Details of the design philosophy, including an overview of the DM design and the project background information are presented by Li et al. (2014a). Details of the construction aspects of the Kitimat LNG deep mixing are presented by Wilson et al. (2014)."

Jan 1, 2015