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By Jean Wehbe, Daniel C. Brahana

"The new Mercedes-Benz Stadium (MBS), home of the Atlanta Falcons, is part of a new era of stadium construction in the U.S. These new-age stadiums are larger and have more amenities than their predecessors. Many of the MBS’s features, including its innovative retractable roof, result in extraordinary structural loads. The roof structure is supported by a series of mega columns that bear on eight large caps, six of which are supported by drilled piers. Each of the pier caps contains between 8 and 16 drilled piers that bear in the underlying bedrock. The design pier diameters are 6 and 6.5 ft (1.8 m and 1.9 m). Augercast piles were used to support two of the mega column caps. Drilled piers, augercast piles, aggregate piers and spread footings were used to support the more lightly loaded portions of the structure.The focus of this article is the construction aspects of the drilled pier foundations. Initially, a fairly extensive drilled pier load test program was performed. Load testing included a Statnamic compression test, two Osterberg Cell tests and two lateral tests. Production pier installation included over 3,800 linear ft (1,158.2 m) of earth excavation and over 1,350 linear ft (411.4 m) of hard rock excavation. The piers contain more than 6,600 cu yd (4,587.3 cu m) of concrete and 1,100 tons (998 tonnes) of reinforcing steel. Drilled pier installation took about 4.5 months. ABE Enterprises was the specialty foundation subcontractor and Bauer-Pileco was the equipment provider.Site and Subsurface ConditionsThe project site is in downtown Atlanta and was originally occupied by residential buildings. A portion of the site was later developed as a rail yard, and other areas contained light manufacturing, warehouses and other relatively light structures. For the past 15 to 20 years the site had been used for surface parking.Beneath a surficial layer of manmade fill, soil test borings at the site generally encountered residual soil, partially weathered rock and the parent bedrock. The bedrock at the site is highly variable, both in elevation and in hardness/quality. The depth to rock is reasonably uniform within the western two-thirds of the site at about 20 to 50 ft (6 to 15.2 m), with a few exceptions. In the eastern third of the site, the rock drops off dramatically to the north and east. In one mega column cap, there was almost 80 ft (24.3 m) in elevation difference. In two borings in the cap that were 20 ft (6.1 m) apart, the top of rock varied in elevation by 34 ft (10.3 m)"

Jan 1, 2016

By M. Melih Demirkan, Jared Deible, Michael Rosenmeier, Mazen Elias Adib, Juan J. Gutierrez, Raghav Ramanathan

Dewatering and groundwater control is required frequently for construction projects and needs to be accounted for and dealt with care during design and construction to complete the project successfully. Dewatering can cause changes in porewater pressure, which changes the effective vertical stress in a soil mass. Dewatering can also cause changes in groundwater chemistry which in turn can cause changes in porewater pressure and also dissolution of soluble minerals in the soil and rock. The Guideline developed in this study addresses the engineering issues, approaches to lessen the potential risks associated with construction dewatering, and presents dewatering practices to support dewatering applications regulated by the Municipality of Abu Dhabi City (ADM) in the United Arab Emirates (UAE). The subsurface condition within the city presents significant geotechnical problems due to presence of shallow subsurface cavities and soluble minerals in the soil and rock. Therefore it is critical to develop standards for dewatering practices to provide information for local dewatering engineers and contractors with special emphasis to control and to eliminate the subsidence/collapse problems related to dewatering projects within the Abu Dhabi city. The ADM is also responsible for approval of permit applications for projects that involve dewatering. In order to minimize the risk related to subsidence/collapse problems due to dewatering, construction companies and dewatering contractors need to be informed about possible mitigative measures that can be employed to reduce risks. The guidelines were developed as part of this study based on detailed analysis of the local subsurface conditions. A set of rules and regulations are developed for geotechnical and hydrogeological investigations, dewatering design and monitoring criteria depending on the hazard zones, proximity of excavation to critical structures, excavation depth. The Guidelines include examples of permit application packages for three types of dewatering projects; one involving shallow dewatering, one involving intermediate depth dewatering, and one involving deep dewatering. These Guidelines are considered as living document and will be updated as required, as additional information is collected and additional local experience is gained.

Jan 1, 2016

By Nagarajan. D, Raja Rajan. K, Vijayakumar. T

Major bridges crossing mighty rivers must be constructed in flowing water. Constructing the sub-structure in water has been a challenging job for contractor. Special construction techniques with marine fleets to be adopted for waterfront construction. Enabling works like temporary piling platform and cofferdam used for pile and pile cap construction. Apart from this, enabling works like load out jetty to transport the materials from land to water; temporary walkway for access of workman to work location; temporary access bridge for construction vehicles movement; temporary liners for tower crane foundation; Concrete block to act as dead man anchor for barge movements were all required by the contractor for smooth functioning of site as per construction schedule. Investment in enabling works by contractor plays a significant role on profit margin of the project and of course with utmost safety. Design of enabling works for waterfront structures involves hydrological data like afflux, bathymetry survey, current force, scour depth and wave force to be taken cautiously for safe and economic design. Type of foundation and pile/well cap top level corresponding to water levels shall influence the construction scheme. Usage of geotechnical software like Wallap and Plaxis required for enabling work design to enhance the safety of the structure. Bathymetry and soil condition play a critical role in design and construction of enabling works. Water Discharge quantity in river along with water levels like low water level, high flood level, seasonal fluctuation of water levels has a great impact on design of enabling works. Establishing enabling works for waterfront construction near to an existing bridge is an additional challenge for the contractor. Along with design, constructing the enabling works in water requires special construction methodology and sequence of work. This paper shall provide insights on overview of design and construction of enabling works for waterfront construction.

Nov 1, 2022

By Andrew R. Klaetsch, Peter W. Deming

"The Washington Avenue tunnel in Kingston, NY was completed in 1912 to convey combined storm water and sanitary sewage. Over a mile in length, the tunnel was driven almost entirely in bedrock, with the exception of an approximately 170 foot long brick arch segment constructed in soil. About 90 years after the tunnel was put into service, persistent subsidence problems and sinkholes were observed in Washington Avenue above the shield-driven soil tunnel segment, eventually causing the important traffic thoroughfare to be closed. Subsequent tunnel inspections revealed a breach in the brick arch and a significant volume of fine soil within the tunnel. A two-phase remediation program was implemented to control seepage, reduce soil migration, and remedy sinkhole problems. The first phase included in-situ soil densification by vibratory pile probe driving to improve density in shallow sandy soil loosened by ground loss. The second phase included installation of a continuous soilcrete arch structure over and alongside the tunnel, extending to rock or compact glacial till and spanning the length of the soil tunnel segment. Overlapping vertical soilcrete columns were installed through interlayered sandy and clayey silt by jet grouting to form a continuous arch structure, using grout parameters verified by full scale field testing.PROJECT BACKGROUNDThe Washington Avenue tunnel in Kingston, NY (Figure 1) was completed in 1912 to convey combined storm water and sanitary sewage to Rondout Creek by the Board of Water Supply of the City of New York. The tunnel is over a mile in length and constructed primarily in rock. Contract documents indicate the tunnel was designed with a horseshoe shape at least 3 ft wide and 5.5 ft high."

Jan 1, 2016

By Martin D. Larisch

The construction of diaphragm walls and most large-diameter bored piles (piers) is often carried out under drilling support fluids to temporarily stabilise the excavation prior to concrete placement. In most cases such fluids are either mineral-based slurries (bentonite) or polymer support fluids. The working mechanisms of these two fluid types are fundamentally different. Designers need to consider possible fluid-related impacts on the permanent design performance of the project-specific deep foundations as well as for the temporary excavation stage during construction. Robust design methods for bentonite slurry-supported excavations have been developed in the last few decades and the working principles and associated risks of such mineral-based slurries are understood reasonably well. However, such meth-ods have not been developed in detail for polymer-based drilling fluids. This document provides a brief overview of the main characteristics of bentonite- and polymer-based drilling fluids as a guide for construction practitioners and design engineers alike. The paper also high-lights some common construction risks related to casing installation and the selection of suitable fluid systems for different ground conditions. Typical defects caused by the incorrect application of drilling support fluids, and their pro-active mitigation, are discussed, too. In addition, the basic concepts of sta-bility calculations for bentonite fluid-supported deep excavations are briefly introduced and their ap-plicability for other fluid types such as polymer-based support fluids or water are reviewed.

Nov 1, 2022

By Diane Reid, Antonio Marinucci, Robin Mao

Super Cells are an innovative, open-shaped bi-directional static load testing device used to promote concrete flow during placement while utilizing greater cross-sectional area of the pile to achieve large applied axial loads at relatively low hydraulic pressures (≤ 250 bar). This paper describes the results of multi-level load testing performed on a sacrificial drilled shaft that was 3.8 m (12.7 ft) in diameter and 110.6 m (363 ft) in length for the Jiaxing-Shaoxing River Crossing Bridge that spans Hangzhou Bay in Shaoxing, China. The test shaft was instrumented with embedded strain gauges and telltale rods along with displacement transducers at the top of the pile to measure the load-induced displacements along the length of the shaft. Load testing was performed twice using a Super Cell placed near the tip of the shaft, prior and subsequent to tip post-grouting, and then again using a Super Cell placed higher in the shaft. The axial resistance for the tested conventional drilled shaft was more than 5 times greater than the estimated axial resistance. In addition, the axial resistance after tip post-grouting (347,100 kN (39,033 ton)) was about 5.3% greater than the ungrouted axial resistance (329,600 kN (37,050 ton)). INTRODUCTION During the past few decades, the magnitude of axial, lateral, and flexural loading has considerably increased due to updated design codes, larger superstructures, and the manner in which extreme event loading (e.g. seismic and scour) is incorporated into design. The diameter and depths to which bored piles or drilled shafts are constructed have increased considerably during the last three decades due to the advancements in equipment technology and capabilities. In addition, monoshaft foundations have become increasingly used, as one large drilled shaft is able to replace a group of smaller diameter piles connected by a cap. Correspondingly, adequate strata, for both side and end resistance, must be discovered/determined as well as achievable to be able to construct the required foundations to support the greater design demands. As design demands have increased, the need to ensure integrity, quality, and performance of a constructed drilled shaft has become ever more crucial. Load tests are essential to validate design assumptions of side and end resistances, to assess the behavior and load transfer characteristics of the constructed drilled shafts, and to evaluate construction methods. Load tests utilizing a bi-directional static load testing (BDSLT) device can achieve considerably large applied axial loads and can be performed more economically, in less time, and in a much safer manner than conventional top-down static load testing methods.

Jan 1, 2019

By Peter Cali, David Yang, Rakshya Shrestha, Ralph Griffin, Sushil Kafle, Motoji Watanabe

"As a part of the ‘US Army Corps of Engineers - New Orleans to Venice, Louisiana Hurricane Protection Project’, deep mixing ground improvement was designed to reinforce the soft ground for the emergency repair of a 7297-foot (2,224 m) long section of the Mississippi River West Bank levee in Buras Levee District under the contract ‘Emergency Levee Repairs – Contract P-17A, Plaquemines Parish, Louisiana’. The ground improvement utilizes a series of soil-cement panels oriented in the transverse direction of the levee. Each soil-cement panel consists of overlapped columns installed by the deep mixing method (DMM). DMM is performed from the existing top of levee and extended to competent stratum at depths varying from 26 feet (7.9 m) to 47 feet (14.3 m) below the working platform. The main purpose of the DMM panels is to provide shear resistance to the levee against lateral loads at high flood water condition. The DMM panels support the additional vertical load created by the increased height of the levee for hurricane protection and control the long-term settlement of the remediated levee, which might otherwise occur due to the compression of soft foundation soils. The total amount of DMM treatment is approximately 54,000 cubic yards (41,500 cubic meters). This paper reviews the project background, subsurface soil conditions and presents the design, construction and quality control of the deep mixing work for this levee repair project.INTRODUCTIONIn August 2005, Hurricane Katrina caused major damage to the federal and non-federal flood control projects in southeast Louisiana. In September 2005, Hurricane Rita caused further damage to this flood protection system. In an effort to minimize further damage and to enhance the protection level, certain non-federal levees located on the west bank of the Mississippi river in Plaquemines Parish, Louisiana were incorporated into the New Orleans to Venice Hurricane Protection project by the US Army Corps of Engineers (USACE). DMM techniques were then utilized by the USACE in several of these emergency projects and in many medium sized projects between 2006 and 2010 (Bruce et al. 2012). This project (called P-17A hereafter) which forms a part of this protection system is executed under the contract Emergency Levee Repairs, Contract P-17A. This is one of the largest projects of the USACE after LPV- 111. The huge LPV-111 project (5.5 miles (8.9 km) of levee) treated by DMM), the largest DMM project ever conducted outside Japan, began in 2010 and was completed in 2012 (Cali et al. 2012, Bruce et al. 2012).DMM is utilized at P-17A to construct a series of soil-cement panels oriented in the transverse direction of the existing levee to provide shear resistance to the levee against the lateral load during high flood water condition. The project extends 7297-foot (2,224 m) along the West Bank Levee of the Mississippi River in the Buras district of Louisiana, parallel to Louisiana Highway 23 (LA-23) as shown in Figure 1. It is located approximately 60 miles (96 km) south-east of downtown New Orleans."

Jan 1, 2015

By X. L. Huang

This paper deals with the experimental and theoretic study of the contact pressure beneath the deep foundation of Beijing International Hotel, The experiments have been carried out in project and in model footing 6.6m2. The result of measurements shows the contact pressure at the edge is greater than that at the center. The theoretic analysis on the base of elastic theorey is in good agreement with the test if the proposed assumption used.

Jan 1, 2010

By D. S. Yang, Y. D. Wang, G. Watanabe, A. P. Notaro

"Deep soil mixing (DSM) walls reinforced with steel soldier piles were installed for excavation support and groundwater control for the construction of a grade separation structure at the intersection of Warren Avenue and the Union Pacific Railroad in Fremont, California to mitigate traffic conditions during the busy commute hours and for the extension of San Francisco Bay Area Rapid Transit (BART) system. Instead of treating the DSM wall as a temporary structure, the reinforced DSM walls were integrated in the design of the permanent structures including retaining walls, and the abutments and pier of the railroad and BART bridges. The integration of steel members inside the DSM wall as part of the permanent structures is an innovation which facilitates the use of top down construction techniques to speed construction and utilizes the steel soldier piles that would have been disregarded after the use as a temporary shoring wall. This paper will review the background of the project and DSM method and present the design and construction of the DSM wall composite structure for this grade separation project.INTRODUCTIONUsing the concept of mixed-in-place piles initiated in the 1950’s in the United States, Japanese contractors in the late 1960’s and early 1970’s installed single mixed-in-place soil-cement piles along a row to create a wall for excavation support and groundwater control. Due to the high groundwater conditions in most of the coastal cities in Japan, wall continuity and uniformity became the requirements of soil-cement walls for reliable groundwater control to minimize ground movement and impacts to adjacent buildings and facilities. In late 1970s, Seiko Kogyo, Co. Ltd. developed the Soil Mix Wall (SMW) method, which uses a triple auger mixing tool to improve the uniformity and continuity of soilcement wall. The SMW method is considered a wall installation method in contrast to the Cement Deep Mixing (CDM) method, also developed in Japan, for ground stabilization in soft soils, especially in the marine environment. In the U.S., generic terms like DMM (Deep Mixing Method), DSM (Deep Soil Mixing) or CDSM (Cement Deep Soil Mixing) are used by various government agencies and private organizations to describe the soil mixing technologies without differentiating the origin, procedure and application. The method used in this project is called DSM method by the project owner, Santa Clara Valley Transportation Authority (VTA), to produce a single continuous soil-cement wall for use as shoring wall and composite structure. The mixing tool for DSM wall installation can vary from 3 to 6 mixing augers. Due to the need to install steel soldier piles into the DSM wall for resisting lateral forces, high water cement ratio slurry with bentonite is used to produce low strength soil-cement, generally in the range of 70 to 100 psi (500 to 690 kPa), with high fluidity to facilitate the installation of steel soldier piles. To maintain the wall continuity for groundwater control, overlapping of one full DSM column is made between neighboring elements using two types of installation procedures as illustrated in Figures 1a and 1b. Steel soldier piles, as shown in Figure 2, are used to reinforce the soil-cement wall to resist the lateral shear force and bending moment induced during the excavation."

Jan 1, 2015

By Paul J. Lewis

Estimation of the axial side shear resistance of drilled shaft rock sockets is directly related to the unconfined compressive strength of the bedrock. Commonly, the mean unconfined compressive strength value is calculated from a range of laboratory test results and is used to estimate the side shear of the bedrock. This paper presents the results from a full scale axial load test performed on an 8.5-feet-diameter drilled shaft rock socket, and compares measured side shear values to estimated values for two different rock strata. Measured side shear values correlated well with the design value calculated for the "strong" rock stratum, but did not correlate well with the design value calculated for the "weak" rock stratum. The mean unconfined compressive strength was used to calculate the side shear in both strata, but review of the laboratory data indicates that this value may not have been appropriate for the weak stratum due to a large variation in the laboratory test results. Also included in this paper is a discussion of the subsurface conditions, the laboratory test results, and the methodology used to design the drilled shaft rock sockets for axial and lateral resistance.

Jan 1, 2005

By Kevin Green, Iván Contreras, Aaron Grosser, Jon Ausdemore, Rachel Leier, Amr Ragy

"Construction of a new tailings dam was required to increase tailings storage capacity at a trona mine near Green River, Wyoming. The new dam was founded on overburden soils underlain by both fractured and competent bedrock. The stored tailings and water had high salt content, resulting in salty seepage water. To reduce the impact of the salty water on groundwater and the Green River, the design of the new tailings dam included a 257,260 SF (23,900 m2) seepage cutoff extending into competent rock.An extensive subsurface characterization was performed prior to completing the design and suitable seepage cutoff methods were evaluated. The approach selected was a full replacement panel using hydromill and clamshell for construction and self-hardening slurry (SHS) for the wall material. Laboratory testing was performed and ongoing monitoring has continued to evaluate the hydraulic conductivity and seepage cutoff performance in the briny environment.The paper includes project background, the collaborative approach and outcomes of the QA/QC program, and the monitoring results for the seepage cutoff wall.PROJECT BACKGROUNDCiner Wyoming, LLC (formerly OCI Wyoming, LLC) owns and operates the Big Island Mine facility near Green River, Wyoming. This underground trona mine has produced soda ash since 1962. The Greater Green River Basin covers much of southwestern Wyoming and extends into northeastern Utah and northwestern Colorado. The Ciner facility is located in the Green River Basin, which is part of the Wyoming Basin physiographic province. The Green River runs to the west and the south of the Ciner facility.Beginning in the early 1990s, Ciner primarily disposed tailings underground in mined-out panels. However, in recent years, underground storage has become limited and some disposal has transitioned to the ground surface. Long-term planning revealed a need to expand Ciner’s surface tailings disposal capabilities. Pond 2, a previously permitted disposal area, was identified as the most viable location for a storage facility. The Pond 2 site is directly north of the Ciner plant facilities, northwest of the active Upper Delta tailings storage facility, and northeast of the Green River (Fig 1)."

Jan 1, 2016

By A. Rod Kern, Michael A. McNicholas, Yaser Taheri

Deep foundations were required for construction of an 18,000 ft2 (1,672 m2) 4-story office building and an adjacent 23,750 ft2 (2,206 m2) 5-story parking garage in Queens, New York due to an existing uncontrolled fill layer ranging from 15-20 ft (4.6 - 6.1 m) in thickness beneath the building footprint. The geotechnical engineers for the project initially selected auger cast-in-place (ACIP) piles over driven piles to limit the impact of noise and vibrations on the surrounding neighborhood. Ultimately, drilled displacement piles (DDP) were installed since this method offered a more economical solution that would generate the required pile capacity with shorter drill depths and would also mitigate spoils volume. During installation of test piles by the geotechnical contractor retained for the foundation work, multiple unanticipated soil conditions were encountered that would adversely affect the constructability of the piles. The existing fill contained significantly more natural and manmade obstructions than expected and the underlying glacial soil became too dense to penetrate at shallower depths than anticipated. This paper discusses how these issues were overcome through pre-drilling and the use of detailed instrumented test pile data coupled with in-house engineering capability to proactively re-evaluate minimum pile lengths at any given location and keep the project on track. INTRODUCTION Geotechnical work in the New York City market presents soil conditions that can be highly variable and challenging due to the presence of uncontrolled urban fill placed over the native soils. Construction in this area can therefore pose many unforeseen challenges, even with detailed geotechnical analysis being performed at project sites. A case in point is a construction site in Queens, New York. The proposed site development consisted of construction of a 4-story office building with a footprint of 18,000 ft2 (1672 m2) and a stand-alone 5-level parking garage with a footprint of 23,750 ft2 (2206 m2), together with associated new pavements and utilities. The site is bordered by a mix of commercial buildings and residential properties on all sides. Depth of the uncontrolled nature of the fill extended up to 20 ft (6.1 m) below street grade. Given the significant cost associated with removal and replacement, deep foundations were recommended to bypass the unsuitable soils and support the structures at depth where good bearing material existed.

Jan 1, 2019

By Akshay Sakhuja, M. S. Karthika, R. Vignesh

"The bridge across River Mandovi in Goa is a cable stay bridge structure proposed parallel, along existing bridges for regulation and reduction of vehicular traffic; the entire bridge structure is supported on pile foundation socketed in rock. This paper describes drilling related issue encountered during execution of pile where bed rock varies considerably from factual geotechnical investigation, which in turn affected the productivity of bored piles socketed in rock then chiseling is advocated for rock socketing with limited number of blows based on penetration resistance of rock encountered or equivalent energy principle to increase the productivity and also to avoid excess chiseling which otherwise would have fractured the rock mass below and around the pile tip resulting in increased settlement of pile subjected to design load. Contractor decision on socket length have been taken without compromising either quality or productivity; the paper presents various procedures and the equipment involved for installation of pile in rock along with the conclusion related to termination of pile in rock and also the lessons learned in process.INTRODUCTIONPile foundations are generally used to transfer heavy loads in deeper bearing stratum if the soil immediately beneath the base of the foundation does not have sufficient capacity. The bridge across River Mandovi, Goa is in its construction phase as a part of the development plan of Goa State Infrastructure Development Corporation Ltd (GSIDC). The project was awarded to M/s. L&T Construction, Heavy Civil Infrastructure; subsequently the geotechnical investigation was awarded to M/s L&T Geostructures.The client has specified the foundation of the bridge as rock-socketed. Rock socketing is generally done to achieve higher bearing pressure through concrete-rock shear interface which many building codes permit. The design and construction of rock socketed pile foundation entails a detailed analysis and judgement on the superstructure loads, predominant geological conditions as well as ground water levels. The termination of pile is normally based on thumb rule of half to three times the pile diameter into the rock. Quite often the criteria is based on chisel penetration rate (Gandhi,1990) In fact, this is the key factor to consider appropriate and economical depth of embedment of pile into rock stratum which necessitates enormous understanding on the type and quality of rock strata encountered which may significantly influence the selection of suitable rotary rig for pile installation. Such criteria are site specific and also applicable for the set of equipment used for the particular project."

Jan 1, 2015

By Satyajit Vaidya, Rudolph Frizzi, Quadri Owokoniran

"This paper presents a case history in the design and construction of high-capacity drilled shafts for the iconic New York Wheel presently being constructed along the St. George area waterfront in northern Staten Island, New York. Although the site is located in an area that offers views of the Statue of Liberty, the Manhattan skyline, and New York Harbor, the variable and challenging subsurface conditions at the site and the structural loading requirements for Wheel erection and service conditions presented geotechnical design and construction challenges. The paper focuses on site and subsurface conditions, drilled shaft design and construction details, results of Osterberg-cell and lateral load testing, and load test data analysis and evaluation.PROJECT DESCRIPTIONThe proposed 630-foot (190 m) -tall New York Wheel (the Wheel) is projected to be one of the tallest observation wheels in the world. Upon completion, the Wheel will be capable of carrying over 1,400 passengers in its 36 capsules. The Wheel site is located along New York Harbor offering views of the Statue of Liberty, the Manhattan skyline, and the New York Harbor; see Fig. 1. The Wheel structure is sited along the waterfront, and served by a 3-story terminal located south of the Wheel in the eastern portion of the site and having a footprint area of about 34,250 sq-ft (3,180 sq-m). A 4-story parking Garage, with a footprint of about 112,840 sq-ft (10,480 sqm), is to be constructed south of the Wheel in the central and western portions of the site.SITE AND SUBSURFACE CONDITIONSThe site’s close proximity to the New York Harbor presented geotechnical challenges because the site is located in an area that was once beyond the historic shoreline of Staten Island. The site is an about 350,000-sq-ft (32,500-sq-m) parcel generally bounded by the Richmond County Bank Ballpark to the southeast, the 9-11 Memorial to the east, Bank Street to the north and northeast, and Richmond Terrace and an associated retaining wall to the southwest and south. A 50-ft (15-m) -wide New York City Transit Easement, with an active on-grade service area and tracks, is located in the southern portion of the site. See Fig. 2 for site location and approximate location of the Wheel foundation footprint."

Jan 1, 2016

By Felix Cheng

Extensions to the Convention Centre in Adelaide, South Australia consisted in part of construction over the existing railway system comprising nine rail lines and passenger platforms. Vibro-pile (Aust) won the design and construct tender with a solution comprising over 500 cast insitu concrete piles. The pile types were 500 to 900mm diameter non-displacement CFA piles and 400mm diameter displacement V-piles. The V-pile is a cast insitu screw pile developed by Vibropile (Aust) Pty Ltd. Both pile types were installed with minimal noise and vibration required for the project, while the displacement V-pile had the advantage over the CFA pile by developing the same pile capacity but with a smaller diameter and with minimal spoil. The latter was important in alleviating spoil removal problems near the railway tracks and disposal of potentially contaminated spoil. The results of dynamic compression load testing and static lateral load testing indicated that the performance of a 400 mm V-pile was equivalent to a 500 mm CFA for this site. The lateral load testing indicated that the surficial soils have a major influence on the load-deflection response, but despite the site containing up to 4 m of filled ground, the piles were found to carry the required lateral loads satisfactorily.

Jan 1, 2002

By Filippo Maria Leoni, Wesley Schmutzler, Matteo Bertoni

"Deep Mixing Method (DMM) for the Rio Puerto Nuevo Project (Project) in San Juan was chosen by the Corps of Engineers to improve the soils adjacent to a 92 inch ID forced sewer main relocation and to improve the soils for the base of a new drainage channel. The soils to be improved consisted of sandy fill, soft clays, organics and stiff, plastic clays. A pre-construction soil investigation campaign, followed by a Bench Scale Mixing Programme and a Full Scale Field Test were performed during the pre-construction stage to assess soil properties, select binder type and dosage, and disclose the most suitable combination of injection parameters to improve the different soil layers. Production started at the end of August 2012 and was completed in October 2013; over 3,000 DMM elements were installed to a maximum depth of 57 ft below ground for a total gross volume of approximately 125,000 cubic yard. Each element consisted of two 5.5 ft diameter overlapping columns installed simultaneously, and their layout was such to meet the 100% Area Replacement Ratio required by the design. The ground improvement was successfully completed despite some difficulties due to a considerable amount of obstructions. Wet grab sampling and UCS testing of the retrieved specimens were designed as the main QC/QA method for the verification of the quality of the ground improvement. Upon completion of production, approximately 3,000 specimens were cast. The contract also required continuous coring of at least 12 randomly selected DMM elements and the testing of 8 cored specimens per bore for strength assessment. This paper will illustrate means and methods used in the field to construct the designed ground improvement and the results of the QC/QA program, with a focus on the differences between wet grab and coring sampling methods.INTRODUCTIONThe Rio Puerto Nuevo project involved the stabilization of a major drainage channel using the Deep Mixing Method (DMM), and the relocation of a 92 inch ID forced main sanitary sewer outfall. Previously, in 2004, a 40 x 16 x 2,000 ft. box culvert was installed under a different contract to convey runoff waters to the ocean.However, the connection between this culvert and the upstream network of channels was not constructed due to the presence of the forced main sewer pipe. In order for the drainage system to be completed and function properly, the 92 inch ID forced main needed to be lowered about 20 ft to allow for proper drainage.DMM was chosen by the US Army Corps of Engineers to stabilize the drainage channel as well as improve the soil under the relocated sewer main. The DMM was arranged in different zones (A through E) with variable top and bottom design elevations as can be seen in the typical cross section for Zone A (deeper and with a higher strength requirement) and Zone B as an example (Figure 1)."

Jan 1, 2015

By Achyut Kumar Allady, Praveen Arumughan

NCHRP Synthesis 418 (2011) entitled, “Developing Production Pile Driving Criteria from Test Pile Data” details the occurrence of dichotomy between pile Skin resistance and pile Tip resistance mobilizations at different times for different hammer blows during pile driving operations. With increasing usage of High Strain Dynamic Testing (HSDT) the engineering community started paying more attention to this occurrence of dichotomy resulting in overdriving, pile damage, increased claims, and loss of time. To overcome the dichotomy limitations of HSDT, NCHRP recommends, “the use of superposition to combine the back-calculated tip resistance from a blow on initial drive or from redrive with the back-calculated skin resistance from the early blows at the beginning of restrike”. However, the current practice of external mounted gauges and signal matching for a single blow are unable to evaluate independently the Skin resistance and Tip resistance to achieve the goal of determining the optimum Total Pile Capacity using the superposition. This paper discusses advancements of science and technology with sensors embedded at the pile top and pile tip, the data collected is analyzed by the state-of-the-art FDOT Method to determine Skin and Tip resistances independently for every blow. Independent Tip and Skin resistances each with a Resistance Factor can be summed up to obtain optimum Total Pile Capacity. Additional benefits of determining independent Skin and Tip resistances include obtaining lost skin capacity due to scour, due to pre-drilling/preforming and uplift tension capacity. Furthermore, the benefits of embedded sensors include increased quality control/quality assurance through 100% testing, accelerated construction, life cycle monitoring and asset management.

May 1, 2022

By Dinesh Hinduja, Pérez: Miguel

"Large structures are generally exposed to dynamic and structural loading. They require usually either foundation connected to hard rock through sockets or driven foundations, which encounter boulders as well.In this regards drilling hard-rock sockets or boulder offshore or onshore can be a challenging job especially when deep foundations are mandatory. To overcome the challenge, specialized equipment like a Pile Top Drilling rig (PBAs) can be used, which have to be correctly set-up and operated in order to get its maximum drilling performance. High performance drilling with PBAs requires maximizing key elements of its operation. The configuration and management of the drill string components are important. The key elements are constant weight on bit which is done by adjusting ballast and managing thrust force; and selection of cutters and proper flowing discharge.The methodology is based on the experience from over 40 years of building and operating PBAs for different project applications. These applications include drilling offshore and onshore for:?Superstructures and buildings?Drilling platforms, barges and jack-ups?Harbours, jetties, dry docks and dolphins?Bridges, piers and causeways?Marine sewerage diffusers?Offshore wind farms?Dam rehabilitationMHWirth documented methodologies demonstrate that by using PBAs properly it is possible to improves performance of underwater drilling for hard-rock sockets and boulders which ultimately reduces project-cost.Background. There is a significant percentage of total project cost in structural foundations. Equipment capabilities and technics to drill shaft with rock-sockets and embedded boulders onshore and offshore are highly developed due to the dramatic equipment advancement and experience in the last 40 years. Formerly, driven piles accounted for the majority of foundations either onshore or offshore, following the experience of previous practice in the market. Nowadays, deep drilled foundations can be constructed to carry the load through the overburden down to the sound load carrying rock or soil.Scope and objectives. The overall objectives of this study are:?Synthesis information on current practices to drill shaft with rock-socket and/or embedded boulders onshore and offshore with Pile Top Drill Rigs?Identify the principal challenges evolving with practice?Provide suggestions for improvements in the construction of drilled shafts through proper operation of Pile Top Drill Rigs?Convey information through case studies and experiences"

Jan 1, 2015

By Martin B. Hudson, Andrew K. Cho, Rolff B. Knobel, Les R. Chernauskas, Jonathan L. Ernst

ABSTRACT The Bruce Museum, located in Greenwich, Connecticut, is home to an extensive display of art and natural history exhibitions. A large addition was designed to be constructed adjacent to the museum requiring new spread footings to be installed up to 16.5 feet below the existing foundations. The soil conditions at the site consist of highly variable sand and gravel overlying weathered rock and sound bedrock. The Contract Documents called for traditional foundation underpinning. Traditional underpinning techniques, however, presented two major challenges on this Project; (1) deep underpinning pits would be required involving multiple levels and staging with tieback support and (2) the highly variable soil and bedrock composition and elevations presented uncertainty in the design and construction of the pits. In lieu of traditional underpinning, Geosciences Testing and Research, Inc. (GTR) proposed an “active” soil nail underpinning system. A major reason that the soil nail underpinning option was feasible, related to the fact that the soil nails and facing could be installed slightly in front of the existing footings rather than directly underneath the existing footings. The soil nail wall design involved one to four rows of soil nails with nail positions and wall depth able to be adjusted “on the fly” as excavation progressed depending on the field conditions encountered. To create the “active system,” the soil nails were pre-loaded to mitigate wall deformations that would be associated with a standard passive soil nail wall design. To evaluate the performance of the active soil nail wall and confirm design assumptions, an extensive automated monitoring, on-site testing and inspection program was proposed and executed by GTR to monitor deformations of the wall and the museum in real-time, evaluate and confirm bedrock and soil bond stresses and ensure that each soil nail was pre-loaded and locked off. Careful analysis, planning, and use of the observational method illustrates the importance of collaboration between design and construction personnel and applying engineering judgement throughout construction. The use of the observational method includes the potential for modifying design based on conditions observed. This paper presents a unique case study of the “active” soil nail underpinning system to support and protect sensitive structures, close collaboration between design and construction facilitated by real-time deformation monitoring, and its successful application as a safe and cost-effective alternative to traditional underpinning.

Oct 1, 2022

"The Metropolitan St. Louis Sewer District (MSD) in Missouri, the country’s fourth largest sewer system, is upgrading its storm and wastewater infrastructure in a 23-yearlong, $4.7 billion initiative called “Project Clear.” Historically, during times of intense precipitation, the current sewer system becomes overwhelmed. The primary goals of this project are to improve water quality and to alleviate many wastewater concerns in the St. Louis region by planning, designing and building community rainscaping, system improvements and an ambitious program of maintenance and repair.Part of the system renovation has focused on constructing underground tunnels for storm water storage, permitting controlled drainage of runoff, and preventing overflows into rivers and streams. Construction plans for these storage tunnels called for eight vertical intake and ventilation shafts to be bored from the ground surface. These shafts will then be intercepted in the bedrock at a depth of about 150 ft (45.7 m) during the excavation of the 3,000 ft (915 m) long underground tunnel that will be about 28 ft (8.5 m) in diameter. According to John Deeken , a geotechnical engineer with Black & Veatch Corp. and construction manager for the Maline Creek project, the drilling and blasting technique for creating the shafts was ruled out because the project was located in a residential neighborhood. “We could have used rock coring or a cutter head, but the drop shaft for this project is constructed within 10 ft (3.05 m) of an existing 108 in (274 cm) diameter sewer main,” Deeken said. “We had to take precautions to avoid damage to it.”A primary planning mandate of all MSD Project Clear phases requires minimized impact on traffic and residents. The canister drilling method enabled work to be confined to the median of a residential boulevard running perpendicular to the side street without detouring traffic. In addition, canister drilling offered a highly-precise means to create the shafts, leaving a smooth-sided borehole, right on target. Ground conditions in this 132 in (3.35 m) diameter intake shaft were wet due to the high groundwater levels and close proximity to the Mississippi River. “They’ve been finding shale in 2 to 6 ft (0.6 to 1.8 m) layers between weathered layers of Mississippian limestone,” said Dan Spiecher, technician at Center Rock (CRI). “The 2 ft (0.6 m) layers we can punch through. The 6 ft (1.8 m) layers slow us down.”"

Jan 1, 2017