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By Renato P. Cunha

The paper explores a parametric analysis of a four-pile group in contact (hence piled raft) and without contact (hence standard pile group) with the superficial soil layer, under a combined set of loadings (moment M, vertical V and horizontal H forces). The major design parameters of interest, as total and differential settlements, and raft bending moments and shear stresses are assessed under aforementioned distinct conditions. The slenderness ratio of the piles is also varied along the analyses, allowing the establishment of its influence on the derived parameters.

Jan 1, 2006

By John P. Briand III, Douglas J. Aghjayan, Robert E. Fosse

This paper highlights the successful pile load testing program for the redevelopment of Pier One in East Boston, Massachusetts. Pier One is a 5.4-acre parcel on a dormant waterfront site used in the 1950s as a warehouse and distribution facility. The developer plans to re-use the existing 14-inch-diameter concrete-filled steel pipe piles to support four 5- to 7-story apartment buildings above a 2-story parking garage. A pile load testing program was developed to establish if the existing piles could support design loads of 240 kips for project financial feasibility and up to 300 kips for a significant reduction in future foundation costs. The Phase 1 program consisted of statnamic and dynamic load testing on two piles with two loading intervals (200 and 240 kips). Based upon the favorable results of the Phase 1 program, the Phase 2 program involved statnamic load testing on two piles and dynamic load testing on ten piles with three loading intervals (200, 240, and 300 kips). The Phase 2 program confirmed the favorable results which were applied across varying strata thicknesses and pile embedment depths. The average allowable capacity for the piles tested was greater than 300 kips with pile movement up to 0.3 inches.

By Kyle R. Lackner, Jared P. Williams

"The Sutter Butte Flood Control Agency initiated the Feather River West Levee (FRWL) Program in 2010 to bring 35 miles of levee along the Feather River into compliance with applicable Federal and State standards for levees protecting urban areas. A combination of soil-bentonite cutoff walls, soil-cement-bentonite cutoff walls, and seepage berms will reduce flood risk by correcting under and through seepage deficiencies and remove more than 34,000 properties from the FEMA Special Flood Hazard Areas. The FRWL program includes a combined total of 7,744,803 square feet (SF) of cutoff wall planned to be constructed between 2013 and 2015. Cutoff wall construction methods to meet the design depths included conventional excavation to a depth of 85 feet and deep soil mixing for depths up to 120 feet. A key component of the FRWL program was the development of site specific mix designs using the design boring logs to evaluate the expected backfill gradation and permeability results. Issues that required a partnership between Contractors, Owner and Engineers included substantial Archaeological and Cultural Resource delays, significant depth changes due to a change in competent key, right of way acquisitions for abutting land, and the magnitude of the project in a resource limited industry.IntroductionThe Feather River watershed basin is located 50 miles north of Sacramento, CA and incorporates the agriculture producing communities of Yuba City, Live Oak, Gridley and Biggs. These communities are protected from flooding by levees that contain under-seepage and through-seepage deficiencies and were the cause of major failures in 1955, 1986 and 1997. The Feather River West Levee (FRWL) program was initiated by the Sutter Butte Flood Control Agency (SBFCA) in 2010. The long term objective of SBFCA is to correct the levee deficiencies and provide 200 year flood protection to more than 34,000 at risk properties located within the FEMA Special Flood Hazard Areas.Although FRWL contained a variety of construction components such as earthwork and pipe replacement, the slurry cutoff wall is the primary construction element for addressing under and through seepage deficiencies. From 2013 to 2015 approximately 6,649,210 SF of cutoff wall were installed using conventional excavation and deep soil mixing (DSM) techniques leaving 1,095,593 SF to be completed in 2016. The work was designed, solicited and constructed under two separate contracts, titled Project Area C and Project Area B&D. A summary of the contracts and cutoff wall quantities is presented in Table 1."

Jan 1, 2016

By Mark R. Svinkin

"Construction equipment and operations usually produce soil and structural vibrations which may harmfully affect various structures and also the content of buildings and houses. The level of structural vibrations depends on a number of factors such as characterized sources of vibrations, soil conditions, and susceptibility of structures. There are certain knowledge and experience for managing the effects of construction vibrations which require implementation of condition survey of structures, information on construction dynamic sources and soil conditions at a site, evaluation of possible vibration effects on structure, calculation of ground vibrations before construction, use mitigation measures to decrease vibrations, and a choice of appropriate vibration limits. The paper presents the application of known concepts for assessment of vibration effects on structures from bridge constructions.INTRODUCTIONVibrations producing by construction activities such as pile driving, dynamic compaction of loose soils, demolition work, heavy construction equipment and trucks can affect adjacent and remote structures. Vibration effects on structures, sensitive devices and processes may create significant practical problems. Legal actions are often required for solutions of vibration consequences. The level of construction vibrations depends on dynamic sources, soil conditions at a site in particularly availability of soils with settlement potential, distances from the sources, parameters of waves propagating at a site and susceptibility rating of adjacent and remote structures. It is likely that intolerable structural vibrations from direct vibration effects of impact pile driving and resonant floor vibrations from vibratory pile driving may be induced in adjacent structures to construction sites.Foundation settlements resulting from soil vibrations in loose soils usually occur in the proximity of dynamic sources, but it is important that dynamic settlement may happen at various distances from the source. There are such examples. First, Kaminetzky (1991) mentioned a case history of building settlements developed at a distance of about 305 m (1000 ft) away from a pile driving site. Foundations of the buildings were underpinned on piles down to the tip elevation of the new driven piles to prevent building settlements. Second, Lacy and Gould (1985) shows that the peak particle velocity (PPV) of 2.5 mm/s (0.1 in/s) of ground vibrations could trigger dynamic settlements at distances up to 30.5 m (100 ft) from driven piles."

Jan 1, 2016

By Robert B. Bittner

The new gated dam on the Monongahela River at Braddock, Pennsylvania, was built for the US Army Corps of Engineers using an innovative "In-the-Wef' technology. A key feature of this technology involves construction of the foundations through the water and later mating the completed structure or a shell of the structure to the pre-installed foundation. This paper presents a description of the structure, its foundation, construction sequence and design details required to successfully Implement this technology.

May 11, 2007

By Gene Bryant, Wesley Schmutzler, Matteo Bertoni

The levees where the Mississippi River and the Lower Wood River meet near East Alton Illinois have been a problem area for years due to underseepage. The first phase of the deep cutoff wall was a 2,000-linear foot section that was completed in 2016 for the Illinois Flood Prevention District Council. This section was installed along the Wood River and the Mississippi river to depths of over 135’, The United States Army Corps of Engineers was tasked with continuing the cutoff wall along the Mississippi river. The wall was a continuation of phase I with depths up to 140’. The 1,000’ long cutoff wall was installed through fill, loose sands, cobbles, and sandy clay. The cutoff wall was terminated in either Glacial Till or sound rock. In order to provide wall permeability equal to or less than 1.0 X 10-6 cm/sec a self-hardening slurry (SHS) composed of ordinary Portland cement, slag cement, and water was utilized. The depths reached on this project using SHS is the deepest done to date in the United States. Along with the permeability requirements, a very narrow range for the unconfined compressive strength was specified at 50 – 180 PSI. In order to monitor the ground movement and water level fluctuations during the excavation of the panels with the Hydromill or Clamshell, 6 automated inclinometers were installed and monitored continuously during panel excavation in phase 1. Seven automated piezometers were monitored in phase 2. This paper will give an overview of the project with emphasis on the effect of the excavation on the instrumentation, specifically the reaction of the piezometers as the last panels were installed. INTRODUCTION The project is in Illinois, about 1000 feet downstream from where the Wood River Creek enters the Mississippi River between East Alton, IL and Wood River, IL adjacent to State Highway 143 (Fig. 1). The Wood River Lower Cutoff Wall Phase 2 Project (WR2) was awarded to TREVIICOS SOUTH (TIS) in September 2017. The Main Project features are: Construction of work platform, inclinometers installation and removal, cutoff wall construction by the Self-Hardening Slurry method (approx. 135,000 sf) up to 140' depth, clay cap installation, and site restoration. The levee system along this stretch of the Mississippi River has been plagued by under-seepage for several years. The phenomenon has worsened to varying degrees, depending on location, to the point that remediation was needed to ensure that Levee failure would not be an issue in the future.

Jan 1, 2019

By Joel B. Dellaria, Justin R. Lewis

"No. 9 Walton is a new high-rise condominium building located in the Gold Coast area of Chicago. The adjacent building, Walton on the Park, featured 4 levels of below grade parking and utilized a secant pile wall with integral drilled shafts to support the exterior columns. The earth retention system (ERS) for No. 9 Walton also employed a secant pile wall in combination with drilled shafts. The excavation into the soft Chicago clays varied in depth from 9.75 m to 12.5 m (32 feet to 41 feet) below grade. The temporary excavation support used internal braces from the new secant piles to the existing foundation system of Walton on the Park to provide earth retention. Engineering teams for both projects worked together to design the bracing scheme and connections to ensure that the new excavation and internal bracing would not overstress any elements of the existing structure. Further complicating the project, immediately to the west of the project was a historic church founded on shallow spread footings which required underpinning to minimize movements.The project involved three different building owners, small values for acceptable wall movement, an extensive monitoring program and the challenges of merging two earth retention systems. The subsurface conditions at the site, the adjacent structures, the excavation, and the performance are described. A summary of the design methods and the expected movements of the ERS are discussed, and the performance monitoring system is described. Overall, the ERS performed better than expected with less than 1 inch of measured lateral wall movement during and after the excavation was completed. Measured performance of the ERS is compared to the predicted performance and to the performance requirements for the project.INTRODUCTIONNo. 9 Walton is a new high-rise condominium building in Chicago located in the Gold Coast. The building has 3 levels of below grade parking and 36 levels of living space above grade. Developers originally slated the project to be Phase 2 of the Walton on the Park development built in the mid 2000’s, using portions of the existing foundation system for development of the new structure. However, the housing market crash in 2007 prompted cancellation of Phase 2 of the Walton on the Park development. The property sat undeveloped until 2015 when design and construction for No. 9 Walton began under a new development and design team. The project team completed foundation excavation and below grade structures in 2016 with the first units of the building turned over to new homeowners in 2017.The structural design for No. 9 Walton consisted of reinforced concrete columns and slabs, supported laterally by a heavily reinforced concrete central core. Drilled shafts to rock supported the interior columns and core with the exterior columns and foundations integrally included in the earth retention system. The structure had a below-grade footprint of approximately 1,490 m2 (16,000 ft2). The general excavation extended 9.75 m to 12.5 m (32 feet to 41 feet) below street level with the deepest portions at the central building core mat foundation."

Jan 1, 2017

By Marwa Nabil, Alaa A. Ata

"Recent developments in the analysis of piled rafts has incorporated the load sharing of the raft and the piles to support the superstructure. In the piled-raft system, piles are cast monolithically with the raft and the load is partly transmitted by the raft to the soil directly below it, and partly by the piles to more competent deep soil. While these piles are effective in increasing the bearing capacity and reducing the settlements, they often lead to significant straining actions at the pile head-raft connection which may constitute the weakest link. An attempt to provide a more economical solution, that at the same time overcomes this weak link, is to disconnect the pile heads from the raft and introduce an intermediate cushion of compacted fill. In this case, the piles are considered as reinforcement to the subsoil and will also act as settlement reducers. This paper investigates the load transfers mechanism of the unconnected piled raft with cushion using ABAQUS finite elements Program. The main objective is to provide an in depth analysis of the raft–soil–pile interactions in multi-layered soil under static and seismic loads. The investigated system provides an economical alternative for traditional connected piled raft foundation, where there is no need to reinforce the piles, no need for pile head demolition or expensive waterproofing of the pile head connection. Cost analyses of unconnected versus connected piled raft systems confirmed a cost savings in the construction that may reach from 50 to 70 percent.INTRODUCTIONDesigners around the world have gained more confidence to use the piled-raft as a more realistic system where the raft and the piles share transferring the superstructure loads to shallow and deep soil layers. A further advancement is to use unconnected piled rafts as another practical and economical alternative to the traditional piled rafts. Unconnected piled raft is also synonymous to settlement reducing piles; or simply, soil improvement piles. Liang et al. (2003) has extended the concept of pile-raft-foundation to a new type of foundation called composite piled raft foundation or unconnected piled raft foundation. The foundation is composed of a sand/gravel cushion sandwiched between the raft and piles. The piles group may contain short and long piles. The short piles are constructed of flexible materials such as soil-cement columns or sand-gravel columns, and are used mainly to improve the bearing capacity of shallow soft soil; the long piles, which are made of relatively rigid materials such as concrete, and their main function is to reduce settlements. The cushion plays an important role in mobilizing the bearing capacity of the subsoil and in modifying the load transfer mechanism of the piles. In Shanghai, China, this system of unconnected piled raft has proved to be quite suitable and effective in coastal areas, where deep soft soil deposits exist."

Jan 1, 2016

By Mark Koelling

This paper presents a case history of a ground improvement program conducted in a soft soil environment and seismically active region in the northwest corner of Washington State near the Canadian border. The program was performed over several years, and provided adequate soil bearing conditions for the construction of several structures. Completed development includes separate construction of four adjacent structures, each with unique total and differential settlement requirements and built at approximate two year intervals. Site soils consist of 45 feet of loose saturated sand and silt overlying 70 feet of very soft to stiff (N60 = 0 to 7) normally consolidated clay. Adding to the complexity of the site is the owner?s requirement that all existing structures remain open and in service during construction of each subsequent structure. The paper presents the site geotechnical information and the foundation design issues. Details of a combination of ground improvement methods is presented, including stone columns, wick drains, a preload surcharge, and staged construction to provide soil support for shallow foundation construction of all structures at this site. The soil test results and settlement observations are presented along with QA/QC measures. Lastly, a brief method sustainability comment will be made.

Jan 1, 2010

By Frank Albrecht, Brian McCarthy

"The Ararat Terminal Station (ARTS) is located 190km to the north-west of Melbourne, approximately 1.7km to the north of Elmhurst Township in the Pyrenees region of western Victoria, Australia. The site occupies an area of approximately 7.2 hectare of farmland. The electricity generated by the Ararat Wind Farm is directed to the ARTS terminal station before being connected to the grid. The ARTS structural design includes more than 180 steel yard support structures, three 25m-tall gantry ‘A’ frames, three modular control room buildings, a precast transformer bund, precast fire wall structures and related foundation design. Innovative driven engineered glue laminated timber (glulam) piles in a cruciform shape were used to reduce the foundation construction time, cost and the amount of concrete used in the project. It is the first time that engineered timber piles made from farmed Australian pine trees have been used in a large-scale environmentally-friendly project. Durability of the timber was achieved by H5 treatment and the use of reinforced concrete pile caps to protect the cruciform timber piles at the ground line. A pile-driving sequence was developed based on field trials. The lateral load capacities of the piles were estimated using engineering principles and from full-scale tests in the field. This paper provides an overview of details of engineered timber cruciform piles, durability of timber piles, design information, pile construction procedures, pile-driving procedures, the testing protocol, test results and validation. The test results were compared with predictions from several methods. In addition, potential future applications of similar systems in other infrastructure projects, and opportunities for future improvements are discussed. The structural aspects of this project were presented in a previous paper at the World Conference on Timber Engineering in Vienna in August 2016. See http://wcte2016.conf.tuwien.ac.at/home/ for further information."

Jan 1, 1900

By Shawna Munn, Sarah Speir

Cedarvale Station is one of 25 new Eglinton Crosstown light rail transit (ECLRT) stations along Eglinton Avenue in Toronto. It is an interchange station with the existing Toronto Transit Com- mission (TTC) University subway line and is located at the intersection of two major thoroughfares. The new LRT tunnels run below the existing Yonge Spadina subway line and required total excavation depths of 20 m (65 ft) to facili- tate construction of the new station.

Jan 1, 2023

By Dominic Ammon, Mark Rothbauer, Paul Landers P. E.

Across the Potomac River from the location of the DFI47 Annual Conference (October 2022), in Alexandria, VA, two large permanent anchored walls with a decorative shotcrete face were recently constructed for the North Hill project, a new multi-family and townhome development. The project was executed with a design-build approach for the Fairfax County Redevelopment and Housing Authority with review by the Fairfax County Geotechnical Review Board. The project was constructed in highly variable Potomac group sediments that include high plasticity clay/silt terrace deposits overlying coarser grained materials. The soils were over consolidated and exhibited potential for slickensides from relief of horizontal stresses from past erosion. The wall system was designed to include deep soldier piles and permanent long strand anchors considering past slope instability in the area. As the construction progressed, problematic soil conditions and water issues required modifications to drilling methods. The two permanent walls spanned 800 and 1,000 feet long with a maximum height reaching 40 feet.

Oct 1, 2022

By Lok M. Sharma

Development of brownfields is of great interest in these days. Such fields are not easily adaptable for foundations of structures. The uncertainties in ground behavior present challenges of unpredictable subsidence that could be detrimental to the build up facility. A desalination plant had to be located along the seashore, close to the needy population and the existing water supply infrastructure. The available site had been developed as a recreational park area over a dumped construction demolition debris landfill along the coastline. To construct a desalination plant comprised primarily of large concrete basin tanks on slab, founded on the debris fill had its challenges. A ground improvement system in the form of vibro replacement stone columns was designed and constructed. Approximately 5,000 stone columns were installed across the site. This paper describes the analysis process, the design, field load testing, and installation of stone columns. Difficulties during construction and monitoring aspects are briefly described. The plant started operations in the summer of 2008 and to date has performed satisfactorily. When properly designed, the development of brownfields is achievable at other sites.

Jan 1, 2009

By Frédéric Rocher-Lacoste

On July 2nd, 2007, LCPC and LOADTEST performed a static loading test with an Osterberg-cell on a bored pile of 1600 mm diameter. The 56.50 meters deep test pile constructed by Trevi Spa for Soares da Costa group, was near the Cacheu river in Guinea Bissau. This test was conducted to validate the design of the foundations of the Sao Vicente bridge; a project undertaken by the Ministry of Public Works of the Republic of Guinea Bissau and funded by the European Development Fund. Sub-surface conditions at the test pile location consist primarily of layers of weak sands and clays. The piles were loaded statically using the O-cell® bi-directional method 25 days after concreting. The maximum sustained bi-directional load applied to the pile was 11.7 MN. At the maximum load, the displacements above and below the O-cell assembly were 6.6 mm and 81.9 mm, respectively. The resulting pile head behavior has been calculated for a combined skin friction and end-bearing load of 29.3 MN. The piles were also instrumented using LCPC removable extensometers, which made it possible to measure the mobilization of shaft friction and toe resistance. The adjusted test data indicated that this pile would settle approximately 12.2 mm for the service load of 12MN applied at the head of the pile. This paper provides a very brief presentation of the bridge project and the test pile instrumentation: LCPC removable extensometers and O-cell® instrumentation. The results are detailed and analyzed herein and the combined use of these two instrumentation systems is a world première.

Jan 1, 2008

By Rachael M. Fischer, Daniel J. Woeste, Terence P. Holman

"A new 50 MW biomass renewable energy power plant was planned for construction in southwestern Georgia. The original foundation design consisted of very conservatively designed H-pile groups with vertical and battered piles to carry the axial and lateral loads. The authors conducted a testing program to value-engineer the foundations with the goals of increasing the working axial pile resistance and reducing or eliminating battered piles. Seven test piles were installed and dynamically monitored with a Pile Driving Analyzer (PDA). Two lateral load tests and one tension load test were conducted. The results of our testing program allowed the project team to: (i) increase working pile resistances by factors of 1.5 to 2, reducing the total number of piles by more than 30%, (ii) eliminate the battered piles, and (iii) lessen overall project risk. Poor communication and documentation in a critical area of the site required some piles to be spliced and re-driven after additional PDA testing, establishment of new driving criteria, and consideration of longterm soil setup. This case study emphasizes the economic and risk reduction benefits of a design phase testing program, and the need for consistent communication between parties in the field.INTRODUCTIONA new 50 MW biomass renewable energy power plant (Plant) was planned and constructed in southwestern Georgia. The Plant converts clean wood-based and paper-based waste from existing forestry and pulp operations, waste timber, and maintenance operations into steam that is used by an adjacent manufacturing facility. The Plant also generates electric power with limited greenhouse or particulate emissions for use by a local utility provider.The project site (Site) is located in Dougherty County, in the Coastal Plain physiographic province of Georgia; an area of known karstic activity. Specifically, the Site is underlain at depths of 30 to 45 ft by the Ocala Formation, a light-colored fossiliferous limestone of the Eocene era. According to Watson (1981), the Ocala Formation is 125 to 200 ft thick in the vicinity of the Site and increases in thickness to the southeast. Due to differential weathering, this formation is characterized by an irregular upper surface that transitions from sandy clay/clayey sand into a dense to very dense silt and fine sand locally referred to as limestone. This subsurface stratum is most relevant to the foundation design of the Plant."

Jan 1, 2016

By Venugopal B, M Kumaran, Thomas John, Vetriselvan A

The initial pile load tests are conducted to ensure the geotechnical capacity of the pile in a particular site condition. Normally kentledge method is adopted for the compression pile load tests. In this method the entire kentledge load is loaded above secondary beams which are supported by concrete blocks above the Natural Ground Level. So, it is important to ensure the SBC (for shear and settlement) of the natural ground. In one of our projects initially it was decided to go with kentledge system for initial compression load test on 56m long 1200mm diameter BCIS pile. The test load and total kentledge load were 2160t and 2700t, respectively. The soil strata mainly consisted of clay with low SPT N value and water table almost at ground level. It was suggested to replace top soil using Granular Sub-base (GSB) with good compaction in order to avoid excessive settlement of concrete blocks placed to support the kentledge weight. When the kentledge loading started, even before reaching 10% of total kentledge load, excessive settlement on the GSB layer was observed. This paper describes the problems faced during normal kentledge method and how it was overcome using the liner pile system for initial compression load tests in this particular site condition for higher test load.

Nov 1, 2022

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 Eric Lindquist, John Compagnone, Gabriel Carvajal

"Condon-Johnson & Associates, Inc. (CJA) with the assistance of design consultant, Brierley Associates, designed and installed a water tight shoring system utilizing several ground improvement techniques jointly. Prior to the installation of the shoring system, a test program consisting of the installation and testing of 7 jet grout columns; 1 soil mix panel; 7 soil anchors and 3 tie downs was performed to verify design assumptions. State-of-the-art quality control measures were employed throughout the project.The shoring system consisted of:•,Deep Soil Mixing (DSM) wall utilizing triple axis tooling to install overlapping columns along the perimeter of the proposed excavation to a treatment depth of 54 feet.•,Installation of steel piles in DSM to provide rigidity to the wall.•,Installation of a jet grout bottom seal, installed from surface to a depth of 58 feet below existing grade.•,Installation of 153 soil anchors, 1-1/4” diameter and 47’-6” length, to tie the jet grout bottom seal to the native soil below to resist hydrostatic uplift, installed from existing grade to a depth of 91 feet.•,Installation of walers and pipe struts for internal bracing•,Installation and stressing of 117 tie downs, 1” diameter and 16 ft length, to tie the pump station mat slab to the jet grout bottom seal, installed from inside the excavated pit.Subsurface conditions at the site consist of uncontrolled fill materials to a depth of 20 feet comprised of sandy silt and clayey sand. The native soils underlying the fill generally consist of soft and compressible lean clay and silt with varying amounts of sands to a depth ranging from approximately 44 to 54 feet below ground surface, which in turn are underlain by dense to very dense silty sand. The groundwater elevation at the site is approximately 8 feet below ground surface.This paper covers the design aspects, construction, and quality control measures undertaken by the geotechnical contractor, with supporting figures.INTRODUCTIONThe owner, County Sanitation District No. 2 of Los Angeles County, designed upgrades to their existing Long Beach Main Pumping Plant Facility. The upgrades consist of a new pump station that includes a reinforced concrete below-grade wet well and dry well, a two-story operations building, two 78-inch diameter pipe inlets, two 42-inch diameter discharge pipelines connecting the existing manifold, two pipe junction structures, two insert-type junction structures, and electrical transformers. This paper focuses on the excavation shoring for the new pump station. The original shoring design concept for the pump station excavation illustrated on the contract plans consisted of pressed in sheet piles, a jet grouted bottom seal with soil anchors, 2 levels of internal bracing, and tie-down anchors to resist hydraulic uplift forces on the buried pump station."

Jan 1, 2017

By Brian Wilson, John Scholte, Megan Atkinson

"In November 2004, the residents of the City of Nanaimo, B.C., Canada voted to approve a new conference centre as the centrepiece of a proposed revitalization project for the city’s historic downtown core. The proposal goal was to replace a cluster of derelict buildings with a dynamic and modern complex that would connect existing city facilities to a new conference facility, the Vancouver Island Conference Centre (VICC). The conference centre is expected to create 150 full-time jobs, attract visitors/ delegates from across North America and generate new economic opportunities for local businesses.However, the proposed site posed a number of geotechnical and geoenvironmental challenges. As is often the case with coastal cities, historic growth of the Nanaimo downtown and harbour area was achieved through reclamation of former waterfront areas and inlets. These areas were often infilled with random fills and even wastes, leaving a legacy of variable density heterogeneous fills contaminated with a variety of pollutants. Preliminary assessment of the site indicated a high likelihood of a requirement for deep foundations, a high risk of liquefaction in the event of an earthquake and the presence of both soil and groundwater contamination. Construction would be further complicated by the requirement for two levels of basement parking and the proximity of adjacent buildings and major roadways to the work area.With a limited budget (fixed by the referendum) and timeframe, the city needed a cost-effective solution to proceed with construction. A number of options were considered, but an innovative design using leading-edge Cutter Soil Mixer (CSM) technology best met the geotechnical and budgetary requirements of the site. The CSM approach also addressed the environmental concerns of contaminated soils and groundwater. Golder Associates Innovative Applications (GAIA) Inc., in association with the designers of their parent company Golder Associates Ltd. (Golder), proposed the CSM technology — at the time the first North American application."

Jan 1, 2008

By Michael J. Garlich

Steel sheet piling has a long history of use in a variety of permanent and temporary structures. Current engineering practice uses numerous publications and standards for design guidance. U.S. design guidance is fragmented, with numerous inconsistencies between design guides. To improve current U.S. design practice, the North American Steel Sheet Piling Association has initiated a project to produce a design standard that will unify design procedures and provide specification guidance for engineers and users of steel sheet piling. The wide range of uses for sheet pile structures presents a challenge in developing such a standard. Load factors or allowable stresses acceptable for a temporary retaining wall in soil may reasonably vary from those for a river cofferdam or a dockwall located in sea water. However, it is still possible to provide consistent and rational guidance for such varying uses. The standard also can address sheet pile design aspects often neglected in U.S. publications, such as vertical load capacity and resistance to loads applied parallel to the sheeting.

Jan 1, 2008