Search Documents

By Anthony L. Reynolds, Clifford J. Wren

"The adoption of a significant pile testing regime, the use of Eurocode 7 as the design standard, the development of lean construction techniques, and lateral thinking in overcoming some considerable construction challenges allowed Stent Foundations to construct the foundations for the new Wembley Stadium, London, on time and within budget. In addition to the piling works for the main stadium, and after significant design development, a large number of extra piles were required to raise the new iconic roof Arch to its final position some 133 metres above the ground. A 1,400m long contiguous bored pile wall was also constructed to allow for excavation and formation of the new pitch. INTRODUCTIONHjstorjcal lntrodyctionWembley Stadium is the 'home of English football'. As long ago as the 1880's, Wembley Park leisure grounds had football pitches and running tracks.In 1918 the British Government began planning a British Empire Exhibition with a stadium as its centrepiece. The Exhibition area covered 219 acres and the area on which a former abandoned tower called Watkins Folly had stood was chosen as the site for the new stadium (http://www.wembleystadium.com).The Empire Stadium, as it was originally known, was designed by architects Sir John Simpson and Maxwell Ayerton and the engineer Sir Owen Williams. It took just 300 days to complete at a cost of £750,000 ($1.4m), and was built using 25,000 tons of ferro concrete, 1,000 tons of steel, and over half a million rivets.The Empire Exhibition was a remarkable event, containing fountains, lakes, gardens, and many pavilions, each representing the architectural style of the countries exhibiting. It was opened on 23rd April 1924 and the final attendance was over 27 million, with 4.5 million admissions to the Empire Stadium alone."

Jan 1, 2005

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 P. D. Arumairaj, B. Vani

"Micropiles are small diameter cast insitu reinforced grouted piles and it has been effectively used in many applications of ground improvement. It increases the load carrying capacity of soil and reduces the settlement. It is also used in strengthening existing foundations. In this study, the effect of Solid and Hollow micropiles on the load carrying capacity of footing resting on sand is studied. The effects of solid Micropiles are investigated by conducting experimental model studies. The parameters involved in this study include the position of pile, pile length and pile spacing. Load test was carried out on a model footing resting on sand with solid and hollow micropiles. Load test trail is repeated for footing on Micropiles with varying lengths of 10, 20, and 30 times the diameter and spacing equal to 5, 4, 3, 2 times the diameter. The load-settlement behavior of each case is compared. Optimum length and optimum spacing of both the solid micropile and hollow micropile are determined. It is also observed that the effect of micropiles in the peripheral of footing resists lateral displacement of soil underneath the footing. The micropile beyond significant depth becomes redundant.INTRODUCTIONA micropile is a small diameter (less than 300 mm) drilled and grouted pile that is typically reinforced - FHWA-NHI 2005 (Federal Highway Administration-National Highway Institution). It is constructed by drilling a borehole, placing a steel reinforcing element into the borehole and grouting it. Hollow micropiles are typically reinforced by solid central bar that occupies about onethird of the hole volume. The grout is placed by gravity, under pressure methods or by a combination of both (post grouting). Thus, micropiles can be considered as small drilled-shafts that are specially drilled and grouted.Historically, micropiles have been introduced in Italy as a foundation system mainly for retrofitting and underpinning of structures that had sustained damage during World War II and access for conventional piling equipment was not possible (Bruce, 1988). The second generation of micropiles is a pressure grouted piles with a central mono all thread bar (with diameter up to 89 mm). They are installed by using either an open or cased hole drilling method.A new generation of micropiles, termed Grout injection bore micropiles (IBOR), was developed in the 1980s. The IBOR, currently named hollow bar micropiles, utilizes a continuous all-threaded hollow steel bar as the drilling and grouting conduit, which allows drilling and grouting simultaneously without the need of a casing during drilling. A sacrificial (lost) bit with openings that allow for pressure grouting of the hole is threaded onto the end of the hollow bar and is left in place following drilling. A drilling fluid (air, water, or grout) is introduced through the hollow bar and allows the spoils to flush from the borehole opening. Upon reaching the required depth, neat cement grout is then injected under high pressure into the drilled hole to fill the annulus between the bar and the soil from the bottom to the top. Due to the grouting method employed, the shape of the hollow bar micropile is expected to have a bulb shape with an enlarged base."

Jan 1, 2015

By Jon Huff, Jeffrey Donville, Hannah Iezzoni, Dan Stevenson

Occasionally, in the design of deep foundations for a structure, a single deep foundation element may be used to support a building column. The most common type of element used in such cases is a drilled shaft (also referred to as a drilled pier, caisson, or bored pile). However, as installation capabilities have improved, large diameter augercast piles are increasingly more common. While drilled shafts and augercast piles differ significantly in construction methods, in the eyes of the International Building Code (IBC), both are treated as cast-in-place deep foundations and must comply with many of the same code provisions. Deep foundations are required to be braced such that lateral stability is provided in all directions, however isolated, cast-in-place elements that have a diameter (D) of at least 2-feet and a length (L) not more than 12 times the diameter can be an exception. In response to the concerns raised by some member professionals, the Deep Foundations Institute’s (DFI) Augered Cast-in-Place Pile and Drilled Displacement Pile Committee took a closer look at the code and its applications, the historical development of the code language through the years and performed analytical modeling to evaluate the impact of this ratio on a pile’s stability. The question is whether the limiting ratio included in the IBC 2018 code provisions is justified, or whether different criteria should be used to determine when isolated deep foundation members are allowed.

Sep 8, 2021

By Bernard B. Vannoy, Howard W. Gault, Ramesh Bobba

"Treviicos-Soletanche Joint Venture (JV) and the US Army Corps of Engineers (USACE) have installed a 3800-foot long, 275-foot deep and minimum 2-foot wide secant pile barrier wall at Wolf Creek Dam in Jamestown, KY. This paper describes the methodology employed by the JV and USACE to evaluate the overlap, thickness, and position of the barrier wall. It addresses the contractual requirements, positional uncertainty, and evaluation procedures.These procedures evolved over the course of the project as various issues were identified and procedures developed to evaluate these issues. During the project, it became clear that the JV and USACE could ascertain that the wall thickness and overlap requirements could be met if the overlap based upon Koden data was at least 0.7’ in the left-right direction. For a small number of piles with overlaps between 0.5’ and 0.7’, the piles are contractually compliant yet contain a minor degree of uncertainty in the overlap. Initially, the USACE assumption was that the amount of uncertainty of verticality measurements would require more than a 1-foot measured overlap in the left-right direction to confirm an actual, contractual 6-inch overlap. With time and experience, the limit of measured overlap was reduced in accordance with greater understanding of the equipment capabilities and tolerances. Other lessons learned include the need for Quality Control/Assurance personnel to collect data at the same starting point for every pile.For every pile the JV and USACE compared analog and digital data to provide confidence that the correct digital data was used for overlap calculations. Perhaps the most important lesson learned was the importance of the JV and USACE working together and sharing all data. Overlap analysis was performed by the JV’s Barrier Wall Specialist and a small number of USACE personnel. This resulted in a high level of experience and expertise within a small group.IntroductionThe Treviicos-Soletanche Joint Venture (JV) and the US Army Corps of Engineers (USACE) have installed a 3800-foot long, 275-foot deep, and minimum 2-foot wide secant pile barrier wall at Wolf Creek Dam in Jamestown, KY. The wall was installed through a 6-foot wide Protective Concrete Embankment Wall (PCEW) which was installed two feet into rock. The PCEW protects the embankment from erosion of drilling fluids during subsequent operations. Below the PCEW the piles were installed to a specified elevation (staggered at 475’ and 473’ below the 748.2’ work platform). The Ordovician limestone and shale bedrock is flat lying with few vertical fractures. These conditions facilitate the advancement of pilot holes with very low deviations (with considerable credit to the JV’s drillers and steering engineers). The pilot holes were spaced on 31.5-inch and 35-inch spacing. Subsequent enlargement of the pilot holes to 50’ resulted in a continuous wall. This paper addresses the requirements and procedures to assure that the wall was as wide, deep and continuous as specified."

Jan 1, 2015

By T Vijayakumar, Vipul Dobhada, Rajesh Patel, Swarnadip Dey, Naveen Babu D

The most challenging scope of any bridge project in marine or inter tidal zone is to construct sub structure like well Foundation, group pile, pile cap etc. Similarly, it also affects the marine environment/ecology to a great extent. Understanding the level of difficulties and aiding to provide an environment friendly solution, various options are analysed to overcome these and found mono pile to be the best alternative in this context. Generally, the foundation type of any bridge constructed in river, marine or intertidal zone in India is preferred for group piles. For the first time, monopile is being accepted as the foundation of bridge in India at Mumbai Coastal Road Project. The diameters of the monopiles used in this project are 2.5 m and 3.2 m. Hence, the challenges involved in monopile construction and experiences to overcome it are worth to share. Here, a brief discussion on environmental, geological issues and the needs of monopile as the foundation of bridge has been discussed. Furthermore, the monopile construction stages and confirmation of monopile capacity through different load tests have been elaborated.

Sep 1, 2022

By William H. Walton, Joel Dellaria, Jeffrey R. Hill

The City of Chicago has a world-renowned skyline and is known for its provocative architecture. The subsurface conditions in the city have allowed for construction of these significant structures. The skyline is supported on caissons as they are called in Chicago or drilled shafts in other locations. Despite the significant strides the industry has made in advancing the drilled shaft, the use of other specialty geotechnical construction techniques like micropiles has not been overlooked in Chicago and the surrounding areas. Micropiles have been utilized to underpin famous existing historic structures like Orchestra Hall any many others. Engineers have used 200 to 600 kip micropiles to underpin compromised, inadequate, or damaged caissons. The paper will discuss the use of drilled shafts, micropiles, and ground improvement over the last 30 years in Chicago using a curated collection of case histories. It will also examine advancing the industry beyond its current technical limitations using these techniques. INTRODUCTION 20,000 years ago, glaciers from the Chicago region left behind sheets of glacial clay till underlain by dense, over consolidated glacial till below: limestone bedrock, found about 100 ft below street level. An unusual feature in this profile is the soft Chicago Blue Clay. Chicago has been called the birthplace of the Skyscraper and drilled shaft foundation, both of which came about in the 19th century. After the Great Fire of 1871, tall new structures were built rapidly and designing a successful foundation was trial and error. The first deep driven wood pile and caisson foundations bypassed the problem layer and found solid support on hardpan till or bedrock below (Schock and Risberg 2013). Once the drilled shaft foundation became acceptable to the Chicago engineering and construction community, building heights and complexity grew dramatically. As the city grew, building foundations were being repurposed. There was also the need to underpin structures for additional loads and shallow foundations for adjacent construction. Hand-dug drilled shafts were an option for some of these restricted access and low headroom sites but a new technique, micropiles, would prove to be the future of retrofit and hard to construct foundations. Micropiles were introduced on a limited basis to the United States market in the 1970s and 80s. In the early 1990s, the Chicago market began to latch onto micropiles and their use has grown significantly as a solution to the most complex foundation problems a maturing skyline has to offer.

Jan 1, 2019

By Thomas Billups, Brendan FitzPatrick, Doug LeDo, David Carchedi

"Working in urban environments presents unique logistical challenges beyond those typically associated with traditional geotechnical analysis and design. These challenges often include working on sites with limited access and laydown area, vibration concerns for adjacent structures and the need to work from variable elevations or within excavations. This paper describes the use of the modular Ductile Iron Pile system, a low-vibration driven micropile, on two urban projects on the Johnson & Wales University campus in Providence, Rhode Island. The paper describes the successful implementation of Ductile Iron Piles installed to develop capacity in end-bearing on one site and friction on the second site. Design, installation and quality control operations are all presented as well as the results of full-scale load testing performed on non-production test piles. This paper is of importance to the industry because it describes a versatile option for project teams as an alternative to traditional micropiles, helical piles or other deep foundation systems for urban sites.INTRODUCTIONWorking in urban environments presents unique logistical challenges beyond those typically associated with traditional geotechnical analysis and design. These challenges often include working on sites with limited access and laydown area, vibration concerns for adjacent structures and the need to work from variable elevations or within excavations. Two recent projects in downtown Providence, Rhode Island faced a combination of problematic soil conditions and urban construction challenges including vibration concerns. Both projects were a part of the Johnson and Wales University campus development. Figure 1 illustrates the urban locations of the sites."

Jan 1, 2016

By Timothy C. Siegel, Paul J. Axtell

The Missouri Department of Transportation (MoDOT) recently replaced the Hurricane Deck Bridge that carries Highway 5 traffic across the Osage Arm of the Lake of the Ozarks in Camden County, Missouri. The former bridge was constructed in the 1920's and was supported on pneumatic caissons bearing on dolostone bedrock. The replacement structure is founded on drilled shafts socketed into the bedrock. During the design phase of this bid-build project, a baseline design was developed and Alternative Technical Concepts (ATC's) were allowed from approved contractors. Those ATC's were confidential and not shared between teams. Either the baseline design or the approved ATC design could be bid by the respective contractors. The baseline design included re-use of the 90-year old caisson foundations. Accordingly, an extensive evaluation of the caissons and underlying bedrock were conducted by coring, laboratory testing, acoustic tele-viewer (ATV), and cross-hole sonic logging (CSL) methods. The results of the investigation indicated the caissons were in excellent condition and suitable for re-use. However, a more cost-effective ATC was submitted, awarded, and constructed that did not re-use the existing caisson foundations but rather reduced the span lengths, increased the number of piers in the water, and supported those piers on drilled shafts. Interestingly, the difference in low bid price between the awarded ATC and the baseline design was less than one percent of the construction cost. This paper describes the multiple foundation designs that were necessary for this interesting project. The various foundation evaluations include the existing pneumatic caissons, large-diameter open-ended pipe piles to support the baseline design, and the design of rock-socketed drilled shafts that were successfully constructed in 2012.

Jan 1, 2017

By Adam Zagorski, Rusty Lucido, Curt Scheyhing

"The current California Department of Transportation (Caltrans) practice based on AASHTO LRFD Bridge Design Specifications is to use the O’Neill and Reese method (FHWA, 1999) for calculating the side resistance and base resistance of Cast-in-Drilled-Hole (CIDH) piles / drilled shafts. In this calculation, end bearing is typically neglected for piles constructed using a wet method due to questionable reliability of end bearing resulting from soil disturbance and inadequate cleaning of the base. Pressure grouting below the tips of drilled shafts in cohesionless soils has long been used worldwide to provide reliable end bearing capacity, but for decades it was relatively unused in this country. It has been used increasingly in the United States over the last decade. Before this project tip grouting has not been utilized on or accepted by Caltrans to maximize piles end bearing capacity. This project proved that tip grouting to mobilize reliable base resistance can be successfully implemented on a full-scale bridge project requiring over 350 large diameter shafts.For the Gerald Desmond Bridge Replacement Project, Shimmick/FCC/Impregilo, JV utilized a temporary Oscillator casing to the full depth to install CIDH piles. Piles were constructed by the wet method and then pressure grouted below the pile tip. A tip grouting procedure for these large diameter shafts was developed and tested to specifically address the geology and constraints of the project. This procedure was then proven during the Load Testing of test piles during the Test Shaft construction phase of the project. Tests showed a minimum reliable base resistance of 150 ksf could be mobilized in very dense sand at a downward movement of 5% of the pile diameter for piles ranging from 4.9 to 8.2 feet in diameter. By tip grouting, the length and diameter of the piles were significantly reduced."

Jan 1, 2017

By C. O. Riggs

Geotechnical exploration in North America, in particular, exploration for deep foundations analyses, is currently and generally performed following the most basic sampling and insitu testing methods and techniques. Some would surely say that the state-of-practice severely lags the state-of-the-art. Probably more than 90% of all deep foundations, both driven piles and drilled piers, installed in North America are initially analyzed and designed, i. e. geotechnically, on the basis of either the soil penetration resistance obtained by performing the "Standard Penetration Test" (SPT), or from laboratory shear tests performed on samples obtained using 76-mm (3-in.) nominal diameter, thin wall, "Shelby tube" samplers. The use of design data obtained with other exploration methods and devices, such as bore hole pressure meters, flat plate dilatometers, even cone penetrometers, occur on the fringes of practice and often in conjunction with the use of the two simpler methods of analysis. This basic approach probably represents an attempt of the profession to use, as much as possible, common, easily understood and easily communicated procedures in all geologic environments. The characteristics of drill rigs with the required drilling and samplng tools vary somewhat from region to region in North America according to the physiography of the area of use, the types of exploration data required on a day-to-day basis, the philosophy of the engineers and geologists that use the exploration data and the financial resources of the drill rig owner. The physical capability of the exploration drill rig used on a project can have a significant effect on the quality of samples or insitu tests. The physical configuration and the quality of the drill and the drilling, sampling and testing tools not only provide the mechanical capability to obtain data but affect the attitude of the field exploration crew and the quality of work. This complete presentation is taken, for the most part, from a book in preparation for publication: "Geotechnical Exploration and Site Characterization" by C. Riggs, A. Hatheway and N. Schmidt. The book is scheduled for completion during 1987.

Jan 1, 2010

By Rick Deschamps, Amanda Blank, Matthew W. Drewek, Michael P. Walker

The Prairie du Sac Dam, located on the Wisconsin River, northwest of Madison, Wisconsin, was constructed 1912-1914. The spillway is an Ambursen-type, consisting of a series timber pile supported pier and buttress walls and rollway slab. The timber piles supporting the spillway, numbering approximately 5,000, have deteriorated, and the spillway structure was underpinned with over 700 micropiles as part of a design-build construction project. The underpinning micropiles needed to be arranged to avoid interferences with the existing timber piles, requiring the micropiles to be installed in the open spaces between the piers and buttresses. Inevitably, the installation of the new micropiles encountered obstructions, including existing timber piles out of alignment, as well as timber piles used to support the original construction activities and sheet pile used to control water during the original construction. This paper discusses using finite element analysis to model the spillway structure to estimate the vertical and horizontal stiffness with an extensive sensitivity analysis was performed during the design phase to account for anticipated construction challenges and potential variations in the underpinning performance. The inherent rigidity of the spillway structure allowed for load distribution to the underpinning system even when new micropiles needed to be re-located and aligned to avoid interferences with existing timber piles and other abandoned foundation elements dating back to original construction.

Sep 8, 2021

By Steve Davidow, Scott Tunison

As the demand for electric power grows and generation facilities are constructed in more remote areas, the industry faces an increasing number of foundation construction challenges. The importance of quality geotechnical information prior to construction is accentuated by the linear nature of the projects and the potential for drastic changes from one end to the other, but is often difficult or unfeasible to obtain. Alignments are crossing remote, rugged and/or environmentally protected terrain, and completing a comprehensive geotechnical program is made challenging from an access or economic standpoint, or both. In these situations, the industry needs a flexible foundation alternative. This paper will present micropiles as that alternative and demonstrate how the implementation of micropile foundations mitigated these challenges on the Koolau-Wailupe 46 kV Circuits in Oahu, Hawaii, which involved rugged, steep slopes and helicopter construction methods. It will detail the selection of micropiles over other foundation options, micropile and steel pile cap design methodologies, foundation construction, and quality control. Special attention will be given to the unique geology in the area, and why precise identification of saprolite and basalt layers was integral to the successful performance of the foundations. The intention is to communicate the benefits of a flexible solution based on continuous collaboration between design and construction.

By Brenton Cook, Daniel Mageau, Larry Applegate, Aaron McCain

"Ground freezing was successfully used to create an impermeable barrier wall along 3,000 feet of the downtown Seattle waterfront as part of the Seattle Seawall Replacement Project. This $360 million re-development involved removing the original 1930-era seawall and replacing it with a new, seismically resistant concrete wall supported on fill soil improved by jet-grout. The replacement wall was one of the largest construction projects in the state of Washington at the time. Ground freezing is typically used as both a structural shoring wall and groundwater cutoff. However, at this project it was used primarily as a cutoff wall to stop groundwater seepage into the 16-foot deep excavation from the landside areas.The project was divided into ten boxes (sections), each typically 200 to 600 feet in length. Only a few boxes were under construction at one time to reduce the impact on tourist-dependent local businesses. Soil conditions in the freeze zone consisted of sand, gravel and silt fill with abundant wood and debris. Tidally influenced groundwater, much of it contaminated, was difficult and expensive to control using wells during initial stages of construction. For all subsequent stages, a frozen soil wall extending to about 35 feet in depth was used to stop groundwater seepage into the excavation. An additional benefit of ground freezing included elimination of potential settlement beneath nearby buildings, utilities, and the Alaskan Way Viaduct that would likely have occurred with the use of conventional dewatering wells. The frozen soil wall crossed more than 130 buried utility locations (including water, sewer, storm, electrical, fiber optic, phone, gas, steam) with no damage. The frozen soil wall was very successful and limited groundwater influx from the landside to the seawall excavation to a negligible amount so that pumping, storage and treatment of contaminated groundwater was essentially eliminated."

Jan 1, 2016

By Ali Ebrahimi, Meena L. Viswanath, John F. Beech, Mustafa B. Erten, Ming Zhu

"Excessive deformation of a cantilever sheetpile wall can occur due to dredging, excavation, backfilling, or long-term creep behavior of soil. A buttressing berm constructed in front of the wall can be considered as a mitigation technique to prevent or decrease the deformation by increasing the passive earth pressure and thus improving the wall stability. The effect of the buttressing berm on the stability and deformation of a sheetpile depends on the berm geometry (i.e., the thickness/depth and the width) as well as the properties of the sheetpile and the adjacent soils. A parametric study was conducted using a conventional limit equilibrium method. Design charts were prepared to evaluate the effect of a buttressing berm and the soil friction angle on the wall stability and deformation. These charts can be used as a tool by geotechnical engineers to make a quick estimate of the required size of a buttressing berm in case of calculated or unexpected excessive deformation of a sheetpile. An analysis of the effect of a buttressing berm on the stresses and deformation of a sheetpile was also compared with the results from finite element analysis. The results of this comparison are discussed.INTRODUCTIONCantilever sheetpile walls are commonly used to support excavations. Sheetpiles are hot rolled or cold formed sections of steel made to interlock with adjacent sections to form a continuous structure providing lateral support. Sheetpile walls can be cantilever walls or anchored with tiebacks. To construct a cantilever sheetpile wall, sheetpiles are driven by pile drivers or vibrated in to a design depth sufficiently below the depth of excavation. Excavation can then proceed in front of the sheetpile wall, which resists the earth pressure loading from behind the wall. The design depth and geometry of the sheetpile wall depend on the soil conditions, the depth of excavation, and the tolerable deformation. In certain cases, when a small buttress of soil can be left immediately adjacent to the sheetpile wall, the required depth or geometry of the sheetpile wall can be reduced or adjusted, which can significantly decrease the cost of procuring and installing the wall. Such a buttress can also serve as a short-term or long-term remedy in case of observed excessive deformation in a constructed wall. Traditional methods of analyzing the stability of a sheetpile wall do not account for the passive pressure effects of this small buttress. In this paper, a parametric study was performed for a variety of soil types and wall and buttress geometries by implementing traditional limit equilibrium methods in commercial software and design charts were created illustrating the effect of a buttressing berm on sheetpile deflection. Selected cases were then modeled in a finite element software to compare the results with the traditional limit equilibrium method. The resulting design charts can be used as a tool by geotechnical engineers looking to reduce the design geometry of a sheetpile wall or address observed excessive deformation in a constructed sheetpile wall."

Jan 1, 2016

By Unnikrishnan Nair, Sandeep S. Nikam, Sanjay D. Patil, Prabir C. Basu

"Mumbai Metropolitan Region Development Authority (MMRDA) entrusted to implement Monorail Systems in various parts of Mumbai Metropolitan Region (MMR) with the objective to supplement the present transport system in MMR. The stretch of Monorail is starting from Sant Gadge Maharaj Chowk (SGMC) and extending up to Chembur Railway Station, divided into 2 phases. Construction of Phase 1 (Chembur to Wadala Depot) is complete and Phase 2 (Wadala Depot to SGMC) is under construction.Monorail runs on prestressed girder (guide beam) of span ranging from 20m to 28m supported on pier founded upon group of end bearing piles embedded in rock, pile group ranging from 2-4 piles of diameter 1000mm each.For the purpose of site characterization, geo-technical investigations were carried out along the alignment of Monorail system as mentioned above. These investigations included field and laboratory tests. The subsurface strata mainly consist of silty sand, gravel, underlain by marine clay extending up to stronger basalt rock with volcanic breccia. Overburden consisting of mainly marine clay ranging from 5.5m to 11m at all locations within the influence zone of settlement.The existing rigid pavement along of Sion-Koliwada and Anik-Wadala were constructed about 5 years prior to the construction of Monorail piers. Before laying the rigid pavement, to improve the geotechnical strength of subsoil (mainly marine clay), ground improvement using stone columns was undertaken by MMRDA. In light of limited right of way, the Monorail piers have been constructed in the median portion of the road. The line became operational on February 2014, in few months it was noticed that, in the vicinity of the Monorail piers, along Sion-Koliwada link and Anik-Wadala link, the Road Pavement Quality Concrete (PQC) panels adjacent to the Monorail piers started showing distress in form of nonuniform settlement of the concrete panels.Effect of pile foundation on pavements/PQC slab distress and possible causes of distress were investigated. Initially the distress was thought to be upheaval of monorail pier cap, but further investigations revealed the same to be soil settlement occurring over time. This paper describes the investigation carried out for identifying the cause of this settlement."

Jan 1, 2015

By James Coull, Brian Wilson, David Siddle

"In 2012, Golder Construction Inc. was awarded a Design-Build contract for the design and construction of an extensive, deep ground improvement scheme to support up to 20 metres (66 ft) high Mechanically Stabilized Earth walls and bulk earthworks required for the development of the proposed Kitimat Liquefied Natural Gas (LNG) facility at Bish Cove, British Columbia (BC). Utilizing Cutter Soil Mixing (CSM) to construct barrettes consisting of overlapping rectangular panels of in-situ cement-treated soils, a deep mixing scheme, covering an area of approximately 12,900 m2 (15,430 yd2) and comprising some 1645 CSM panels to depths of up to 30.7 m (101 ft), was developed to provide the required static and seismic stability for the LNG structures, and meet the project-specific performance criteria.CSM panels were constructed through varying thicknesses and discontinuous layers of fine-grained, very soft to soft marine deposits, and loose to compact sands, with occasional interbeds of dense sands and gravels. Panel completion criteria was based on soil response factors, as measured by the CSM equipment, with the design requiring a typical embedment of about 2 m (7 ft) into dense silty sand to sand and gravel to provide the required bearing. A total volume of approximately 73,900 m3 (96,660 yd3) of soil was treated with cement to consistently yield average unconfined compressive strengths exceeding 2.5 MPa (363 psi).This paper outlines the challenges associated with the construction and quality control of this large deep mixing scheme in highly variable geotechnical conditions at a remote location with barge-only access, and limited communication facilities. Specifically the paper will discuss the logistical challenges faced and solutions adopted for the project; equipment redundancy requirements for a 24/7 operation; the impacts of wear and tear, as well as variability in subsurface conditions on productivity; quality control processes adopted for the project, including the value of provision of an on-site laboratory; and materials handling issues, and their impacts on mix design and quality control."

Jan 1, 2017

By Martin Mcdermott, Kevin Tehansky, Robert Ross, Jeffrey Goodwin

A foundation value engineering redesign is a collaboration between the project owner, original design team, general contractor, foundation contractor and redesign team. Without the acceptance and collaborative effort of all the stakeholders, the redesign process is doomed to failure. For the addition at the Hackensack (New Jersey) University Medical Center (HUMC) we had just such a collaborative effort for the drilled shaft redesign. For a successful redesign effort, the collaboration between the foundation contractor and their redesign team needs to fully exploit the contractor’s specific equipment and experience and convey how to apply this to the project as a whole to ensure everyone is confident that the project design goals are being met. For the HUMC project, applied load testing of the drilled shafts (bi-directional and lateral) were used to provide ultimate geotechnical design values for the redesign effort. By utilizing the contractor’s preferred equipment and the redesign team’s testing and application expertise, the redesign collaboration was able to enhance a good design and make it into a great project.

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 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