Search Documents

By Carlandrea Albonico, Salvatore Miranda

After a brief introduction of the whole Project, the paper describes two special geotechnical engineering solutions provided within the scope of the Galataport Project, in Istanbul, Turkey. The first refers to the new quay of Salıpazarı, which is a combination of retaining structure and ground improvement, formed by a combiwall, a reinforced concrete diaphragm wall and a soil improvement by deep soil mixing (Turbojet). The second, refers to the soil improvement works executed underneath three existing buildings. Single-fluid jet grouting columns had the scope of improving the mechanical properties of the bearing soil and reducing the associated risk of liquefaction. A set of underpinning micropiles was installed in order to allow the excavation of a partial basement inside two of these three buildings. All activities were conducted from inside the existing buildings, with reduced headroom. The paper highlights the importance of employing cutting-edge technologies within the foundation engineering field and state-of-the-art electronic control devices, in parallel with the essential human expertise, in order to obtain the desired results in this high-profile Project.

Nov 1, 2022

By Lance Rasband, Richard Hanke

"Seattle Tunnel Partners (STP) started mining on Seattle’s SR99 tunnel on July 30, 2013, working slowly through a 15 ft (4.6 m) thick fiber-reinforced concrete headwall. Once through the headwall, the machine would move through roughly 400 lineal ft (122 m) of jet grout-improved soil at a rate slightly over 6 ft (1.8 m) per day. It was anticipated that once through the improved area, Bertha—the world’s largest tunnel boring machine—would move at a rate of 35 ft (10.7 m) per day. By the end of October 2013, Bertha had mined roughly 430 ft (131 m), averaging 4.73 ft (1.4 m) per day, and had begun mining within native soils. By the start of December 2013, tunneling reached the 800 ft (244 m) mark and Bertha averaged 12 ft (3.7 m) per day, achieving as much as 42 ft (12.8 m) of progress on some days. However, on December 6, 2013, Bertha began to stumble and all progress quickly came to a halt. Preliminary InvestigationInitial reports stated that an obstruction had stopped the machine in its tracks. Malcolm Drilling received an early morning call on Sunday, December 8, 2013, from STP to rapidly mobilize a Bauer BG-50 drill rig with crews to investigate what was hindering Bertha’s progress. Malcolm’s equipment and crews flew into action and were completely mobilized and operational by mid-week. The preliminary investigation involved installation of 10 deep dewatering wells to reduce the hydrostatic head within the ground around the machine and allow STP personnel to inspect the cutter head from within the shaft for presence of obstructions. By the close of December 2013, the wells were installed and the dewatering system was fully commissioned. STP crews were then able to inspect the cutter head and found small fragments of a steel pipe wrapped around the outside of the shield. The steel was apparently from an abandoned 10 in (0.25 m) diameter monitoring well casing previously installed by WSDOT (Washington State Department of Transportation) to monitor groundwater conditions for the design and planning of this very project. After the steel was cut out of the head and cleared from Bertha’s path, she attempted to move forward but was only able to manage a slow crawl"

Jan 1, 2015

By John Vickers, William H. Hover, Paul C. Schmall

"Any sudden subsurface issue that threatens the stability of existing buildings or infrastructure is cause for immediate investigation and prompt remedial action. Nowhere is this more true than the nation’s dams and levees. A breach of any kind, no matter how small initially, has the potential to be catastrophic and impact a wide downstream area. Addressing the problem quickly and effectively is therefore critical. When a turbid water discharge developed from a rock drainage embankment at the toe of the earthen dam impounding Cannonsville Reservoir, near Deposit, NY, the source of the problem was quickly identified as resulting from an artesian water release from an underlying permeable silty sand and gravel formation during drilling of three exploratory boreholes in preparation for construction of a hydroelectric plant at the downstream toe area of the dam facility. Work was halted, intense 24-hour monitoring was implemented, and as a risk reduction measure NYCDEP began to draw down the reservoir’s total storage at a rate of a billion gallons per day. Input sought from contractors within the geotechnical community helped result in the design and development of a deep well system to control the artesian pressure. Once this primary objective was accomplished, modified compaction grouting was performed at the borehole locations to densify loosened soils, fill any voids created by the discharge activity, and seal off the permeable aquifer. This paper discusses the dewatering program, specialized drilling techniques required, monitoring and verification of pressures within the dam, and the grouting program.BackgroundCannonsville Dam, owned and operated by the New York City Department of Environmental Protection (NYCDEP), is located in Deposit, New York on the West Branch of the Delaware River and impounds the Cannonsville Reservoir. Built between 1959 and 1964, the dam has an impervious central and upstream core zone keyed into the glacial till foundation, a semi-pervious downstream embankment zone, and a rockfill toe and is approximately 2,800 ft (853.4 m) long and 175 ft (53.3 m) high. The dam is formed by two embankment sections. The left section forms the main embankment blocking the main river channel, while the right section is constructed over a topographic saddle or low ridge. Reservoir level is actively influenced by withdrawals through the West Delaware Tunnel, based on water supply need. Under normal circumstances, water is continuously discharged downstream to the Delaware River."

Jan 1, 2016

By David Chadwick, Paul Marsden, Chris Hughes, Mathias Delapille

"Following damage caused by the 2011 Christchurch earthquakes, the NZ$127.5million Christchurch Town Hall Restoration project is due for completion in 2018. The building is undergoing extensive repairs and a strengthening regime to meet New Zealand’s New Building Standard. One major aspect of the project is the stabilisation of the soil directly beneath the building using interconnected jetgrouting columns installed a cellular configuration, the purpose of this being to decrease the likelihood and severity of foundation movements caused by earthquake-induced soil liquefaction and lateral spreading. The soils encountered on the site ranged from cobbles and gravels through to sandy silts with a significant quantity of timber and rootlets. This wide variation of soil types presented a number of challenges with regard to effective and consistent treatment by jet grouting. The paper presents an overview of the quality assurance practices and also the testing regime adopted on this project.INTRODUCTIONMost of the deformation experienced by the Christchurch Town Hall structure over the course of the Canterbury earthquakes was caused by movement of the underlying ground. Two primary mechanisms of ground deformation were observed:- Liquefaction of the soils underlying the building foundation- Lateral spread of surface soils towards the free face at the river edge which runs 20 metres from the building. This mechanism also resulted in additional vertical settlement of the building foundations.The overall foundation design philosophy adopted by the project team for the Christchurch Town Hall Conservation Project has been to improve the ground directly beneath the structure to mitigate against these two mechanisms of ground movement. Additionally, a robust raft slab is proposed to distribute the foundation loading more evenly and increase the ability of the structure to resist lateral stretch of the underlying ground.The ground improvement system proposed by the Client’s geotechnical consultants, Tonkin &Taylor, comprised a cellular arrangement of interlocking jet grout columns, this arrangement would effectively encapsulate the soil within the cells preventing lateral spread.In total 1,097 interlocking jet grout columns, extending over the entire floor plan of the structure, were required to satisfy the design requirements."

Jan 1, 1900

By Kevin Baumgartner, Steven Babcock

A landfill in Phoenix, AZ reached capacity and was graded over in the 1970s. The property was subdivided into lots in 2007 to create a business park. However, the challenging site conditions caused by the underlaying landfill put into question the feasibility of typical deep foundation systems. Several different foundation systems were evaluated to support the proposed development. The considered systems were: drilled concrete shaft, driven piles, drilled micropiles and helical piles. Soil stability, landfill decomposition, method of installation, flexibility of design, anticipated material, and equipment costs were considered. A system of helical piles with concrete pile caps and grade beams was selected. To mitigate unknown obstructions, holes were drilled through the landfill debris at pile locations and then backfilled with screened granular material. The helical piles were installed through these backfilled holes and advanced to bear in competent native material below the landfill. This method allowed for minimal disturbance of the landfill materials and provided a strong and adaptable foundation. Additional advantages of helical piles on this site include minimal installation vibration, no grout or concrete in the deep foundation, and capacity verification for each pile via torque correlation. Two load tests were performed to verify the design.

Sep 8, 2021

By Kevin Baumgartner, Howard Perko

Common technologies for temporary and permanent support of excavations (SOE) include soldier piles and lagging, secant/tangent piles, slurry walls, and tie-back walls. This paper discusses an innovative technology consisting of helical soil nails with high tensile wire mesh facing.  This novel technology has been used on a number of SOE projects in recent years saving both time and money as well as providing a number of other benefits.  Case histories including Denver Bronco’s training facility, Pulliam Theater, a bridge abutment, and a train platform are presented.  This SOE technology is highly sustainable as both the mesh and soil nails can be removed and re-used, if desired.  The system avoids the need for concrete or grout, so it eliminates curing times and problems associated with field quality assurance and inclement weather placement.  Helical soil nails consist of central pipe or solid steel shafts with small diameter helices spaced over the entire length.  The length of the nails is typically on the order of the height of the excavation.  The nails are spaced relatively close together in rows to reinforce the earth.  The face of the excavation is held back using high tensile strength steel wire mesh over geo-fabric.  The mesh is stretched between the helical soil nails and fastened down using spike plates on the helical nail caps.  Both hand calculation and computer methods for design of this concrete-less alternative to the traditional SOE will be covered. The SNAP 2.0 computer program is used to determine factors of safety with regards to overturning, sliding, and bearing, among other checks.  Through practical applications and real-world calculations, this paper educates the reader on the proper design and application of the helical soil nail and high tensile mesh SOE system.  AutoCAD details and example plans are provided.

Oct 7, 2024

By Haijian Fan

Currently, deep foundation designs for the service limit state are deterministic in nature. The settlements and lateral deflections of deep foundations are calculated by means of numerical techniques whereby the foundation-soil interactions are characterized by discrete load transfer curves such as t-z or p-y curves. The noted deficiency of the deterministic approach is that the uncertainties arising from various sources, such as soil properties and model errors are not considered. To address this deficiency, a performance-based reliability design methodology is developed using Monte Carlo statistical methods. The performance based design criteria are defined in terms of the specified allowable displacement. The input to the numerical solution techniques, including the soil strength parameters, unit weight of the soil are relevant to the generation of the load transfer curves are treated as random field. The well established random field generator algorithm, local averaging subdivision, is used to generate random samples of input, where the mean values, variances, the probability distribution, and correlation structures are required statistical parameters for these random variables. The objective of the performance based reliability design is to determine the optimized foundation dimensions so that the probability of failure is less than the target probability of failure. The probability of failure by the Monte Carlo approach is simply the ratio of the number of unsatisfactory performance to the sample size. A numerical example for laterally loaded drilled shaft is given to illustrate the application of the methodology. The incorporation of the correlation length is shown to be critical for properly accounting for the site soil spatial variability.

Jan 1, 2017

By Garland Likins, Gray Mullins, George Piscsalko

"Quality control of drilled shafts is greatly dependent upon the practices of the site personnel. For drilled shafts cast under slurry, inspection of the hole prior to concreting is very difficult or impossible. There are numerous non-destructive test (NDT) methods currently available to assess the integrity of drilled shafts. This paper will discuss the theory and use of an emerging NDT technology known as Thermal Integrity Profiling (TIP). The Thermal Integrity Profiling method measures the elevated concrete temperatures that occur during the hydration process. These temperature measurements are made along the length of the pile and can determine the integrity over 100% of the pile cross section, both inside and outside the reinforcing cage. With the known shaft volume information, TIP can evaluate the effective shaft radius at each measurement location. With the increased use of TIP on highway projects, there is a need to have standard criteria for shaft acceptance. Shaft acceptance criteria can be based upon thermal measurements and subsequent analysis of the data to determine the average shaft radius, local concrete cover, and cage alignment. With this additional information obtained via the thermal testing method, acceptance methods based upon concrete cover can be developed. In this paper the Thermal Integrity Profiling method will be described, results from a case history will be discussed, and an acceptance criteria based upon concrete cover will be proposed.INTRODUCTIONDrilled shafts are an attractive foundation element in many applications due to their large axial and lateral capacities. When drilled shafts are cast in a dry hole, it is possible to inspect the hole prior to casting, allowing for very basic level of quality control, although the shape of the completed element is still unknown without some form of post construction testing. When drilled shafts are installed where soil conditions are unstable, the shafts will often be cast under slurry to support the surrounding soils during the construction process. When casting a drilled shaft under slurry, it is very difficult to impossible to accurately and efficiently inspect the hole prior to casting concrete and it is equally difficult or impossible to inspect the shaft during the casting process"

Jan 1, 2016

By Brian J. Olson, Kevin Haiar

Originally constructed between 1939 and 1941 as part of Franklin D. Roosevelt’s New Deal programs, the Bonneville to Hood River 115 kV Transmission Line required an infrastructure upgrade to remain reliable and in-service. The line traverses the rugged landscape of the Columbia River Gorge on the Oregon- Washington border, featuring steep, talus slopes; uneven, rocky terrain; and a variety of environmental sensitivities. This paper details the design and construction of 27 micropile foundations for new, fire- hardening steel poles through a particularly challenging stretch of the alignment. The difficult access and environmental constraints at these sites designated them as helicopter-accessible and precluded the collection of detailed geotechnical information prior to construction. Micropiles provided a viable foundation alternative due to their portability and flexibility during construction. Detail will be provided on the extensive preliminary desktop study performed, as well as the process of developing engineering designs to successfully accommodate for variability and unknowns in complex geological conditions. With an increasing number of electric power projects traversing challenging terrain and facing similar obstacles, this project stands to provide valuable lessons learned to the industry.

Sep 8, 2021

By Scott A. Anderson, Benjamin S. Rivers, Derrick D. Dasenbrock, Silas Nichols

Unknown geotechnical conditions are a major source of risk. Unexplored places vastly outnumber the sampled and tested ones, and widely spaced boreholes with intermittent tests and samples are the norm. Sometimes site-specific planning and thought goes into locating these special, tested places, such as basing them on the geologic understanding or anticipated key locations for the structure; more often they are simply evenly distributed. We demonstrate a holographic model that allows viewers to see real data in real space, scaled or not, and to visualize where measurements are taken, what those values are indicating, and where there exists more unknown and more risk. The holographic model shows in an intuitive way, values from Standard Penetration and Cone Penetration tests, and surface geophysics. The mixed reality of this future is that a wide audience – owners, designers, project managers, contractors, and stakeholders interact together in a real space where they see and talk to each other, while at the same time are individually looking all around below or above ground, like a gopher, in a virtual one. Risk in the future will be better managed through more thoughtfully designed investigations and better communication of 3D data in a world of augmented reality. INTRODUCTION This paper explores the use of augmented reality to convey understanding of the subsurface conditions of a bridge site. This is in contrast with the current state of practice where this information is contained in a geotechnical report, and the ideas are also applicable to other structures, earthworks, and excavations. “Augmented reality” describes a situation where a 3D holographic model is displayed for users in such a way that the users experience both the model and the real environment of their setting- such as at a desk, in a meeting room, or in an open space at a project site (Figure 1). The 3D holographic model is used to directly visualize underground features, to see through the earth to the actual locations where explorations are made, samples are obtained, or measurements are taken, design values are assigned, or construction is planned. An immersive model provides the following three powerful functions for users:

Jan 1, 2019

By Tai Luu, Michael McNicholas, James C. McIntyre

The Jersey City Municipal Utilities Authority (JCMUA), discovered that an existing sewer pipe had collapsed under the New Jersey Transit Conrail Railroad between Pine Street and Ash Street in Jersey City New Jersey. Immediate action was taken to abandon the pipe in place and install a new sanitary sewer. The borings showed 10-20 ft (3.04 m.- 6.09 m) of competent fill overlaying approximately 8 ft. (2.44 m.) of compressible peat and organics. Groundwater was at 8 ft (2.44 m) below ground level. The poor condition of the soils at subgrade could not withstand the extreme weight of the jacking machine or the thrust force required to push the casing from the launching pit to receiving pit. The support of excavation (SOE) would therefore not only need to retain the soil to allow the jacking equipment to reach subgrade at 14 ft (4.27m) below working grade, but also the back wall of the SOE would need to be sufficiently robust to function as the reaction block for jacking operations. The alignment and allowable tolerance for the jacked casing was minimal, therefore the performance of the SOE was extremely critical to the success of jacking operations. This paper will discuss in detail the design concepts that were developed and implemented by the team to overcome these obstacles. HISTORY The discovery of a collapsed section of an existing sanitary sewer led the Jersey City Municipal Utilities Authority to act on an emergency contract. The project design team was tasked with developing an abandonment plan for the broken pipe and installation of the new pipe through challenging geology. The new 180 ft.(54.96 m) long, 54-in. (1.37 m) . diameter sewer pipe was designed to be contained within a 72-in. (1.83 m) protective steel casing. The installation of the new sewer pipe would require a detailed understanding of the geology. The geotechnical subcontractor assembled a subsurface investigation report on November 2nd, 2017. It was quickly realized that the only way to replace the pipe was with a jacked pipe system since the large grade change and the Conrail Right of Way created no other alternative. Delaying or closing the railway was absolutely not an option as that particular railway served as the main heavy-haul route to and from Jersey City. It became apparent that a major obstacle to pipe jacking was the challenging geology present across and beneath the proposed sanitary sewer. The following challenges faced the design team prior to the installation of the replacement pipe:

Jan 1, 2019

By Haijian Fan

Currently, deep foundation designs for the service limit state are deterministic in nature. The settlements and lateral deflections of deep foundations are calculated by means of numerical techniques whereby the foundation-soil interactions are characterized by discrete load transfer curves such as t-z or p-y curves. The noted deficiency of the deterministic approach is that the uncertainties arising from various sources, such as soil properties and model errors are not considered. To address this deficiency, a performance-based reliability design methodology is developed using Monte Carlo statistical methods. The performance based design criteria are defined in terms of the specified allowable displacement. The input to the numerical solution techniques, including the soil strength parameters, unit weight of the soil are relevant to the generation of the load transfer curves are treated as random field. The well established random field generator algorithm, local averaging subdivision, is used to generate random samples of input, where the mean values, variances, the probability distribution, and correlation structures are required statistical parameters for these random variables. The objective of the performance based reliability design is to determine the optimized foundation dimensions so that the probability of failure is less than the target probability of failure. The probability of failure by the Monte Carlo approach is simply the ratio of the number of unsatisfactory performance to the sample size. A numerical example for laterally loaded drilled shaft is given to illustrate the application of the methodology. The incorporation of the correlation length is shown to be critical for properly accounting for the site soil spatial variability.

By Richard D. Luark, Fernanda S. Madrona

Deep foundation construction in highly developed urban settings pose unique challenges of working with deep excavations in a relatively confined area while preserving the integrity of nearby structures. For construction of the below grade parking for two, 40-story residential high-rise towers, shoring walls were required to support the maximum 70-foot-deep vertical excavation in downtown Seattle, Washington. The design of the excavation support system consisted of soil nails combined with closely spaced vertical elements to allow the top row of soil nails to be installed up to 10 feet below the ground surface avoiding conflicts with adjacent underground utilities. To limit deflections next to a seven-story building, the upper rows of soil nails were post tensioned. An instrumentation program was implemented to monitor the deflections in the shoring walls by means of vertical inclinometers and optical survey monitoring. The shoring wall performance, designed to limit deflection to less than 1-inch to meet the City of Seattle requirements, was validated by the instrumentation program. This paper provides a discussion of the design and construction of the shoring walls as well as the monitoring data collected from the instrumentation system. PROJECT INFORMATION The project consisted of two residential high-rise towers, with five levels of below grade parking, located at 707 Terry Avenue Seattle, Washington. The project site covers a half city block, approximately 120 feet by 240 feet, and is bounded by Terry Avenue to the east, Columbia Street to the north, Cherry Street to the south, and an alley to the West. Prior to the development, site was occupied by surface parking. A 7-story concrete building with two stories of below grade parking, owned by the Archdiocese of Seattle is located just west of the 16-foot-wide alley. Numerous below grade utilities consisting of electrical, telecommunications, gas, water, sanitary sewer, steam, and storm drains, surround the project. The perimeter below grade parking walls extended within inches of the property boundaries. Topographic relief across the site was on the order of 8 feet. Figure 1 illustrates the site plan view.

Jan 1, 2019

By Mark Zablocki, Dakarai McCoy

Ground vibrations are an unavoidable effect of driving piles and may pose a risk to nearby infrastructure and the comfort of adjacent occupants. Driven-pile-induced ground vibrations are known to vary widely based on ground conditions, pile material, and installation means and methods. A monitoring sensor to record ground vibrations during pile driving is necessary for understanding potential impacts to sensitive infrastructure and should be considered when implementing a monitoring program anticipating ground vibrations. The implementation of a vibration monitoring program historically relies on experiential-based decision-making, which may result in the costly vibration monitoring of low-risk infrastructure. Prior understanding of anticipated ground vibrations is necessary to create an appropriate monitoring program. A framework is proposed for organizing data from past monitoring programs and quantifying the anticipated risk of driven-pile-induced vibrations. An example of risk quantification from data imported to ]a cloud database is presented by comparing driven steel H-pile and prestressed precast concrete vibration monitoring measured and collected by Haley & Aldrich between 2010 and 2020. The methods presented within the example can be applied to quantify a first order approximation of risk for ground vibrations at proposed driven pile sites based on the measured performance of previous sites with similar ground characteristics and pile installation methods. The presented novel data managements tools allow for a quick aggregation of vibration data with similar site conditions.

Sep 8, 2021

By Peter Faust, Peter Hubbard, Kenichi Soga

The European Federation of Foundation Contractors (EFFC) and The Deep Foundations Institute (DFI) have set up a task group to compile a Guide for Working Platforms. The first edition of this Guide has been published in January 2020. The aim of the Guide is to provide reliable methods for design, testing and verification of working platforms for construction equipment, especially in the deep foundation industry where track loads can be excessive due to the nature of its operations. The Guide has identified areas where knowledge is limited. Actual track pressure and its distribution along the length of the tracks is still not well researched. Current recommendation provided in EN 16228-1 are believed to be overly simplified and may lead to conservative requirements for working platform thickness. This paper presents results of a series of field tests where the actual track pressure of a large drilling rig during operation was measured in real time together with the deformation of the working platform. Embedded, distributed fiber optic sensing (DFOS) at different depths throughout the platform allowed for a three-dimensional evaluation of the platform deformation throughout the entire operation. Results will help to develop more reliable recommendations for future safety requirements of working platforms for deep foundation equipment.

May 1, 2022

By Steven D. Scherer

The highest earthquake risk in the United States east of the Rockies is along the New Madrid Fault System, which extends for 193 km (120 miles) through the Central Mississippi Valley from northeastern Arkansas, through southwestern Missouri, western Tennessee and western Kentucky to southern Illinois. Historically, this fault has generated some of the most powerful earthquakes in U.S. history, notably three Magnitude 8 events in 1811. Apart from the West Coast, this region experiences more earthquakes than anywhere else in the United States, with more than 200 events recorded along the fault annually. These events are typically of much lower magnitude than those experienced in California. Most are too small to be felt. However, should a significant event occur, damage can be expected to be widespread because of the underlying geology. In recent years, earthquake preparedness and seismic upgrade of vulnerable structures has become a focus for a number of State Departments of Transportation, including those in Illinois and Missouri where there is a potential for future damage. This paper presents three case histories illustrating three different techniques used to retrofit interstate highway bridge foundations bearing on potentially liquefiable soils. Friction minipiles were installed at the approach span of the I-57 bridge crossing the Mississippi River near Cairo, Illinois to provide additional support to the pile caps in the event of liquefaction of the underlying sands during a seismic event. In St Louis, Missouri, rock-socketed minipiles were installed to increase the capacity of drilled shaft foundations supporting a section of Interstate 64. In Mounds, Illinois, compaction grouting was used to densify loose sand deposits beneath a pile-supported interstate bridge on I-57.

Jan 1, 2001

By Ihab Allam PE, Meeok Kim. PE. Ph. D

The wet weather equalization basin (EB) planned for Pacifica, CA is a 45 feet deep rectangular shaped underground water tank containing over 2.1 million gallons of water, and located only 500 feet away from the Pacific Ocean. The location and size of the water tank, and the geotechnical characteristics of the selected site presented many engineering and construction challenges. The engineering had to consider a structural system which can fit into the limited area of the site and yet need to meet the storage volume requirement. In addition, the system construction should meet the city’s tight budget and schedule.

By David Eley

Coastal communities continue to be at risk with sea levels rising. Along these coastal shorelines, vegetated marshes and ridges provide habitat for wildlife and resiliency against storm surge and erosion in low-lying areas. Often, spoils from maintenance dredging of harbors and rivers are placed in confined disposal sites (impoundments), providing little benefit to the environment. Reusing these spoils to restore low-lying marsh areas that are disappearing because of sea level rise, storm damage, sediment deficits, and other natural and manmade processes is growing trend. Design and construction using dredged sediments in a coastal environment can be challenging. It is critical to design and place fill in sensitive habitats in a controlled, thoughtful manner that enhances the environment. Low dikes are often used to contain fill, which is typically excavated and placed using a hydraulic dredge. These dikes are long linear features, often in a marsh environment, and can be difficult to construct. During construction, the project team (contractors and designers) must understand that these are controlled fill projects, with elevation targets and containment requirements. Distribution of sediments to meet project goals typically requires regular movement of the dredge outfall and monitoring during construction to prevent over-topping of containment dikes, and ensure sufficient fill has been placed to meet project objectives. Dredged sediments can be a renewable resource to restore coastal areas when used in projects that are designed and constructed correctly. In this paper, we will discuss design considerations, construction challenges and construction monitoring, including innovative instrumentation, that can help enhance the sustainability and resiliency of low-lying coastal communities.

Oct 7, 2024

By Dave P. DeClerck

Hardman Construction was faced with the challenge of completing a large earth retention project on a constricted downtown Detroit site, while maintaining a safe and productive worksite. To do so, new technologies using robotic equipment was instituted. HISTORY The historic J.L. Hudson Building (Hudson’s) in Detroit, Michigan was the premier retailer in the city’s downtown district from the 1890s through the 1960s. The massive flagship store sat at 1206 Woodward Avenue, one of the busiest streets in the Detroit area. Hudson’s broke ground in 1891 and would go through twelve renovations and expansions. The last renovations took place in 1946, which gave the building the title of being the largest department store in the world at the time. It spanned an entire city block and boasted 2.2 million square feet of retail space. By the 1970s, Detroit was in an economic downturn. The Hudson’s department store finally closed its doors in 1983. Besides a few working offices, the building sat vacant. The building was unique in that it had four levels underground, offices, mechanical areas, and equipment storage. Following years of neglect, the Hudson’s building was seized by the state and transferred into the hands of the city. The city had it demolished in 1998, (shown in Fig. 1) to construct a new, four- level underground parking garage as well as a potential future above-grade development (Sewlck, 2017). The building was imploded in one of the largest implosions of that time. The building rubble filled the underground rooms and helped to stabilize the exterior concrete walls and keep them from collapsing.

Jan 1, 2019

By Christopher Sammon, Nicholas Turus

"The demand for underground parking in South Florida has increased as a result of changes to the local building code, coupled with developers’ desire to improve building aesthetics and provide much needed walk in retail space for high-end structures. Historically, underground construction was uncommon in South Florida due to the high groundwater level and porous soil/rock. Conventional dewatering methods become ineffective only a short depth below the ground surface and deeper excavations have required a tremie seal solution consisting of wet excavation and the pouring a temporary unreinforced slab under a water head. However, as excavation area and depth increase, the cost and schedule of the tremie seal method become problematic. For these reasons developers and construction teams alike have looked to contractors in South Florida for alternative means of construction.This paper details the construction of two sites in South Florida where Deep Soil Mixing (DSM) technology offered an efficient alternative to tremie seal construction. The Brickell City Centre required excavation of 8 acres to depths of 30 feet, and augercast piles up to 36” diameter and 110 feet in depth. The second site, Jade Signature, required an excavation of up to 41 feet directly adjacent to the Atlantic beachfront. Due to the concerns over differential settlement, the project featured a soil mixed gravity wall that was designed and installed to allow for completion of the tower prior to excavating the adjacent garage.Both projects involved improving every square inch of ground beneath the planned project excavation. The developed DSM seal slab solution creates a nearly impervious excavation at excavation invert with the strength to resist hydrostatic uplift forces. Low permeability site perimeter walls are constructed to complete the sealed excavation and reinforced with either beams or sheet piles for structural support. Augercast piles required for the permanent hydrostatic concrete slab supplement the uplift capacity of the DSM. After DSM and augercast piles are installed from grade, the site is excavated in dry conditions."

Jan 1, 2017