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By Karsten Beekhaus, Sander W. Odijk, Rabea Bahlum, Mazin Adnan, Ayman Abdelh Al Nuaimat, Hassan Farhat

The Arab Potash Company, APC, is one of the 10 largest potash producers of the world. The solar ponds at the Dead Sea, used for the enrichment of the salt content in the brine, are of crucial importance for the first step in the exploitation of the potassium salt. Targeting at the expansion of production in the since over 50 years utilized facilities, the increase of the brine exploitation capacity, reducing the substantial brine seepage losses from the ponds, becomes a crucially required measure. In this context, the remediation measures on the over 11 km long Dyke 1, being a main dyke of the solar ponds system, became inevitable to reduce the brine losses, prevent further development of sinkholes and cavities and hence assuring the stability of the dyke. The highly aggressive environment, the acting hydraulic conditions and the sensitive stratification and nature of the existing ground represented remarkable challenges for the design, as well as its implementation by the construction activities. Royal Haskoning developed a solution addressing the challenges above and targeting at a high sustainability of the executed structure, especially in view of the various geological and hydrological hazards repeatedly occurring in this Dead Sea region, including sinkholes of several meters by diameter and depth. The construction works, consisting of a cut-off wall, with depths reaching down to 31 m, were awarded to Bauer International FZE, a subsidiary of Bauer Spezialtiefbau GmbH. Upon the execution of the first section of 4.2 km length, additional sections were subsequently commissioned, also on further dykes, totaling to about 300,000 m² of cut-off wall. The specific project conditions, such as utilization of cutter technique for the excavation in Halite rock, the stability of open trench exposed to hydrostatic pressure of salt-saturated ground water, resulted in unconventional requirements towards the supporting fluid. The extremely aggressive saline conditions –with a Dead Sea water density of 1.25 tons/m3; one of the world's saltiest water–, were further a decisive factor for the definition of the backfill material concept. Despite its clear advantage for construction of cut-off walls with installed sheet piles, the single-phase system with hardening slurries, fulfilling both functions of excavation support and cut-off wall backfill material, had to be abandoned in favor of the two-phase system, to construct a hybrid cut-off wall made of sheet piles and plastic concrete.

May 1, 2022

By Yu Zhenquan

At the construction site of Bao Shan Iron &. Steel Mill in Shanghai, lots of RC driven piles with length of 50 to 60m were applied. The most unfavourable distribution of stress along the pile shaft was known by measuring the compressive and tensive stresses. With analysing the test results a phenomenon of impact fatigue of RC pile was discovered, the range of impact fatigue and its critical zone can be distinguished. Finally some countermeasures are presented to avoid the impact fatigue of RC long pile.

Jan 1, 1991

By Murray Gamble

A new type of groundwater cutoff wall has been developed at the University of Waterloo. The Waterloo Barrier? is a steel sheet piling system that incorporates a sealable cavity at each interlocking joint. In order to prevent leakage through the joints, the sealable cavity is flushed clean and injected with sealant after the installation of the piling. The installation and sealing procedures of the Waterloo Barrier? system allow for a high degree of quality control resulting in a very low permeability cutoff wall. Based upon field installations, the bulk wall hydraulic conductivity of the Waterloo Barrier? ranges from 10-8 to 10-10 cm/sec. Recent case histories are presented in which Waterloo Barrier? vertical cutoff walls have been used to prevent the off-site migration of contaminated groundwater or soil gases. In some instances, the Waterloo Barrier? system was used in combinations of applications such as preventing the migration of contaminants, redirecting the flow of groundwater, providing structural shoring for soil excavation and aiding in site de-watering processes.

Jan 1, 1997

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

By Ilhan Chang, Ernest Nsabimana, Kiseok Kwak, Juhyung Lee, Young-Hoon Jung

"Numerical analyses were performed to analyze the behavior of two different type of suction piles (mono type and group type) under various soil layer conditions (uniform silty clay layer, uniform silty sand layer, and two-layer deposit consisting of clay and sand layers) and lateral loading locations (top, middle, and bottom of the suction pile). According to the results, mono suction pile shows maximum resistance when load is applied on its middle, regardless of the soil layer conditions, while group suction piles varies significantly according to the allowance on head rotation. When head rotation is allowed, the behavior of group type piles become similar to the behavior of mono suction pile. Whereas, when rotation is prevented, resistance is maximized when load is applied on the top head. Moreover, group suction piles show higher efficiency regardless of the ground condition and geological stratum. For further advances, concrete block on the top of group suction piles are suggested as an effective alternative method to prevent partial rotation and maximize ground resistance for group suction piles.IntroductionWith the development of offshore technology, applications and real site installations of suction piles are increasing significantly nowadays. They are generally used as mooring anchors in various floating structures, marine platforms, and offshore wind turbines. According to its convenience in installation and removal, suction type foundations are becoming good alternatives for deep ocean support systems. The bearing capacity is similar to the bearing behavior of ordinary offshore structures (piles or drilled shafts). The most common use of suction caissons is anchors for catenary mooring lines, where the chain angle at the mudline is close to zero (Randolph, 2002; Sharma, 2004).Recently, it is reported that a huge isolated single suction pile can be replaced by a group of moderatesized suction piles (Randolph et al. 2004). A single monopile is easy to be produced and installed in site. It is expected that monopile foundation is not applicable for deep depths because it has a limitation on penetration according to its huge side skin area (i.e. friction). Moreover, stiffness requirements sometimes render thicker pile wall conditions which are impractical to be produced."

Jan 1, 2017

By Babak Mamaqani

The Regional Connector Transit Corridor (RCC) is the Los Angeles Metro area's ambitious light rail project, running under the city's main thoroughfares, Flower and 2nd streets. When com- pleted, it will alleviate traffic and parking congestion downtown, while connecting thousands of residents living in the bedroom communities of Inland Empire and Long Beach to their jobs there. The rail line of 1.9 mi (3 km), which involves a $1.756 billion (€1.545 billion) budget to construct the under- ground rail line, including three new stations. They are the Grand Av Arts/Bunker Hill station at 2nd and Hope streets, Historic Broadway Station at 2nd Street and Broadway, and Little Tokyo/Arts District Station at 1st Street and Central Avenue, which will offer riders their first "one seat/one fare" ride option from Azuza to Long Beach. Regional Connector Constructors JV is led by Skanska USA Civil West California District Inc. (Skanska), in partnership with Traylor Bros., Inc. (Traylor), to deliver RCC to the Los Angeles County Metropolitan Trans- portation Authority (Metro). PB&A was the structural engineer of record (SEOR) responsible to design the shoring systems for the Grand Av Arts/Bunker Hill Station at 2nd and Hope streets, and Historic Broadway Station at 2nd Street and Broadway. The temporary shoring design for Historic Broadway Station is the focus of this article, and why the project received special recognition as a runner up for DFI's 2021 Outstanding Project Award. Two main challenges are discussed in particular: design of the shoring system considering all construction stages, and design of an underpinning system where the Los Angeles Times Building (Times Building) protruded into the station footprint.

Apr 1, 2022

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 Tracy Brettmann, Melis Sutman, C. Guney Olgen

"The use of energy piles for geothermal heat exchange has been steadily increasing during the last decade, yet there are still pending questions on their behavior during temperature changes. This paper focuses on the thermo-mechanical response of three full-scale energy piles installed in Richmond, TX. The behavior of test piles subjected to thermo-mechanical loadings was studied in situ with the aim of quantifying the thermal influence on the performance and capacity of energy piles. An extensive field test program, including conventional pile loading tests and application of heating-cooling cycles was conducted on the test piles during a period of six weeks. For thermal load applications, the heat exchanger fluid with maximum temperature of 113°F (45°C) and minimum of 47°F (8°C) was circulated in the geothermal loops placed at the center of the test piles. Optical fiber sensors, vibrating wire strain gages, thermistors and thermal integrity profile wires were installed to monitor the strain and temperature variations along the energy piles throughout the field tests. The strain and temperature profiles during heating-cooling cycles on the test piles under static loads and without a maintained load were monitored to investigate the effect of thermo-mechanical and pure thermal loads on the energy piles, respectively. Conventional pile load tests were applied before and after the application of thermal cycles. The results of the pile load tests are compared to evaluate the effect of temperature cycles on pile capacity.IntroductionEnergy piles are deep foundation elements designed to access and exploit the relatively constant temperature of the ground and its heat storage capacity for efficient heating and cooling of buildings. The deep foundation elements that are already in place for structural support are integrated with adsorber pipes to perform as heat exchangers connected to ground source heat pump (GSHP) systems. With the use of energy piles, the heat energy is fed into and withdrawn from the ground for cooling in the summer and heating in the winter, respectively.Energy piles present an innovative way to harvest near-surface geothermal energy and to provide lower carbon emissions, however, there are still pending question on their performance. During heating-cooling cycles, energy piles experience temperature changes, which result in expansion or contraction of the piles."

Jan 1, 2017

By Robert Alperstein, Nidal AbiSaab, Joe Pastore

"This paper describes the design and construction aspects of the foundation support for a 57-story building currently under construction in lower Manhattan. The site is located near the East River with subsurface conditions consisting of about 40-ft [12.2-m] of unsuitable historic fill and soft plastic clay underlain by about 130-ft [39.6-m] of dense sand resting on bedrock. A mat foundation supported on unsuitable soils improved by jet grouting was selected for the project. Design concepts and selection of the engineering properties of the improved and natural foundation soils are discussed. The results of quality control testing and methods to verify design parameters during construction are presented.INTRODUCTIONNew York City (especially Manhattan) is known for its skyline of high rise structures. The geologic conditions in the New York Metropolitan Area influence the selection of foundations and feasibility of high rise construction as noted by Horvath (2013). These conditions include varying depth and quality of bedrock, multiple glacial events during the Pleistocene Epoch, and the effects of human modifications to the subsurface environment. Clusters of relatively taller buildings are generally located in Lower and Midtown Manhattan where sound crystalline bedrock is at relatively shallow depth beneath the ground surface and shallow foundations rest on the bedrock surface. In recent years the use of more costly high capacity driven piles or drilled caissons and deep basements has enabled the high skyline to spread to other areas."

Jan 1, 2016

By Jonathan G. Cannon

"This paper will describe dynamic pile testing conducted during installation of driven octagonal precast prestressed concrete piles used as the foundation for this bridge. The piles were long and hence spliced. A number of the piles showed damage near the splices and the damage location was near the ground surface so that the damage could be verified using visual inspection. The piles and splice configuration are still in use today without modification. Further WEAP driveability analysis has been conducted which demonstrates the effect of the splice on pile stresses and a likely failure mode. A slight modification is proposed to the splice that should prevent the damage on future projects.INTRODUCTIONThe bridge site is located on the Olympic Way, Route 41, about 20km north of the regional centre of Albury, NSW. For a long distance north of the site the Olympic Way ""shadows"" the main Melbourne to Sydney rail line and is located on the Western side and in close proximity. At the bridge site there was previously a sharp dog-leg in the road and a right angle level crossing with the road changing to the Eastern side of the rail line, eventually joining up with the Hume Highway, which in turn now becomes a ring-road through the eastern outskirts of Albury. The dog-leg and rail crossing had warning signs and bells, speed restrictions and rumble strips to warn approaching motorists to reduce speed. Site distance was exceptionally good.Approximately 2years before construction a group of five ""high spirited"" young men from the local area were driving south on the Olympic Way adjacent to a south-bound train. It is understood they interacted with the train crew for a period of time. Unfortunately the car and train collided at the level crossing and all of the young men were killed. There were outpourings of grief in the local community and a decision was made to replace the level crossing with a road-over-rail bridge.The bridge was highly skewed with two piers and two high level abutments with fill embankments on both approaches.GROUND CONDITIONSThe site is open grazing country with approximately level ground at the site with surrounding low hills. The geology was unremarkable with consistent stiff clays for a considerable depth.The design required driven precast prestressed pile foundations with the piles to be driven to a considerable depth.Hard driving with high tension stresses were evident from the start of driving and a variety of different pre-bore lengths were adopted in an attempt to minimise driving and potential for damage. At the abutments the pile locations were predrilled for at least the full embankment depth.PILESThe piles were 550mm octagonal prestressed concrete with the pier piles being single piece and the longer abutment piles being two-piece with a ""standard"" epoxy glued box splice. Pier piles and the initial length of the abutment piles were 24m. The add-on piece used at the abutments was 12m. Pile concrete was grade 50MPa."

Jan 1, 1900

By James N. Mure

The paper describes the design development and construction of bored piles at Pindersfield Hospital, Wakefield, U.K. The piles were of monopile type. Monopile is the term used to describe piles which are constructed without pile caps so that the superstructure columns bear directly on the pile top. Pile geotechnical design was developed from the Site Investigation data and testing of two preliminary piles. Final design philosophy is described. Pile structural design was developed from the loadings applied by the superstructure, and the requirements, tolerances and limitations of monopile construction techniques. Construction was closely controlled in order to achieve a ?right first time? result. The conclusion gives a critique of the system and its value.

Jan 1, 2008

By Richard E. Sylwester

Evaluating surface and subsurface conditions for marine foundations (bridges, causeways, terminals, etc.) is often done with a limited amount of data. Subsurface information for these projects is primarily acquired using traditional methods, such as boreholes, test pits or divers, which tend to be expensive and limited in the area of coverage. A number of geophysical methods, including precision bathymetry, sidescan sonar, and seismic reflection or subbottom profiling are extremely cost-effective and obtain significantly more data than can be acquired using traditional intrusive methods. These geophysical methods provide detailed surface images and continuous profiles of the subsurface stratigraphy. This information can be invaluable for selecting the best location for geotechnical boreholes and to map potential geohazards such as submarine slides and filled or open scour holes. Offshore investigations conducted for a proposed highway bridge (Knik Arm Bridge, Cook Inlet, AK), the retrofit of two existing bridge (Antioch and Dumbarton Bridges, CA) and a proposed cruise ship terminal (Ketchikan, AK) used a combination of geophysical methods to map water depth, detect and map debris on the seabed, map the thickness of unconsolidated sediment, determine the depth to bedrock and identify potential geohazards such as scour holes. The results of the geophysical investigations will be used to select locations for obtaining geotechnical borings, to extrapolate geologic information between existing or proposed boreholes, evaluate the potential depth of scour and design a pile support pier. Geotechnical engineers, offshore contractors and bridge designers are realizing the importance of the early use of offshore geophysics for (i) site characterization, (ii) to reduce the uncertainty of geotechnical conditions thus avoiding designs that may be overly conservative and thus more expensive and (iii) to assist in selecting locations for geotechnical borings.

May 11, 2007

By Faisal Shalzad, Adnan Anwar Malik, Tadashi Maejima, Jiro Kuwano

Single helix screw piles carry most of the structural load through end-bearing if the helix is embedded in the dense bearing layer. The tip condition of the central shaft of the screw pile can be closed, closed with cutting blades, opened with flat cut, and opened with wedge shape cut and its selection is based on the insitu ground conditions. These different end conditions of the central shaft disturb the ground differently, leading to the change in bearing capacity. In this study, an attempt is made to investigate the effect of open and close-end screw piles on installation effort (installation load and torque) and bearing performance in the dense bearing layer. The model steel screw pile with a pile shaft diameter of 21.7 mm and helix diameter of 43 mm is used in this study. Test results show that the open-end screw pile required less installation effort than the close-end pile that penetrated the bearing layer by 1Dhwith an unplugged condition. Further, the open-end screw pile shows a higher bearing response than the close-end screw pile if it enters the bearing layer with an unplugged condition.

Oct 1, 2022

By Gerald Verbeek, Erick Baziw

Stone columns are used in geotechnical site remediation to increase load-bearing capacity and reduce settlement of foundations. Stone columns also improve slope stability and increase the shear strength of a soil. A very challenging problem is to characterize the in-situ shear wave velocities from data acquired from Downhole Seismic Testing (DST) after the insertion of stone columns. DST is an important geotechnical testing tool for site characterization that provides low strain (<10-5) in-situ interval compression and shear wave velocity estimates, but the postanalysis of seismic data acquired from DST in the presence of stone columns is very challenging due to the resulting complicated in-situ soil conditions. To obtain the right results it is necessary to use an algorithm that incorporates source wave raypath refraction. Starting with the Normal Moveout Seismic Cone Tomographic Testing (NMO-SCTT) algorithm developed some years ago, this paper outlines the modifications and additions made to this NMO-SCTT algorithm to facilitate stone column site characterization. To dramatically reduce the optimal solution space for the estimated interval velocities the paper also described a priori conditions that are applied based on the unique nature of the stone column site conditions.

By Gary L. Seider, Dana A. Wesolek, Fred C. Schmednecht

"A new condominium project, The Atelier, developed by Pickus Companies located at the corner of Bryn Mawr and Sheridan in Chicago, IL required an earth retention system to protect the surrounding roads, alley, and existing neighboring apartment bui lding during its construction. Slurry Systems, Inc. (SSI) and Ground Engineering Consultants, Inc. designed the earth retention system using cantilevered sheet piling for three of the four sides: two sides bordering major streets and one side bordering an alley. For the fourth side, which borders an existing occupied brick building, a combination of sheet pil ing and AB. CHANCE® helical screw piers were used. SSI was actively involved in the review process of its earth retention system with the City of Chicago and quickly learned that there was no specific code for hel ical piers/anchors. (It appears that this is the case with most metropolitan cities throughout the United States). Consequently, the approval of underpinning for this project became the critical path, as much testing, calculations, meetings, and other details were required prior to its approval.SSI and AB. CHANCE® recognized that this process for underpinning approval must be seen by other contractors/suppliers who wish to use helical piers/anchors in the City of Chicago. Consequently, this project served as an opportunity to work with the City of Chicago and the City's Building Code Committee in furthering the development of the Helical Piers/Anchors Code, Section 1814. INTRODUCTION - HELICAL PIERSDefinition. A helical pier or anchor consists of one or more helix-shaped steel bearing plate(s) attached to a central steel stem (solid bar or pipe), which is installed by rotating or ""torquing"" into the ground. Each helix is attached near the tip, is circular in plan , and is formed into a screw thread with a defined pitch. Helical piers/anchors are pre-fabricated and can derive their load-carrying capacity through both end bearing and skin friction. The helical piers/anchors can be augmented with grout."

Jan 1, 2005

By Jeffrey C. Schuh, Logan Bloemer, Daniel P. Dietzler

Over the past 30 years, the authors have encountered numerous projects where recognizing the geology, soil properties and groundwater conditions, and considering alternative construction techniques have promoted efficient and cost-saving construction. The construction documents for these projects, produced by various engineering firms, provided basic information on geotechnical conditions. The authors became involved in each project either because there was a problem during design or construction or, as a contractor, won the project because they saw a value engineering opportunity to take advantage of the geologic setting of the project to design and build alternatives to what the designer depicted. Understanding the geologic setting is critical before planning and designing begins. Being able to work with the geology and the materials on site is preferred before specifying more costly and complex solutions, which often require the importing of materials and adherence to unnecessary and/or inappropriate specifications. Failing to understand the geology or not knowing all the techniques available for construction can lead designers to develop solutions that could be inappropriate. This paper presents several examples of value engineering and project performance enhancements developed through knowledge of basic soil mechanics and implementing innovative solutions. History and Background Most people attend DFI meetings, present their experiences, listen to others, and read articles and papers with the hope they can learn from others. Geotechnical engineers and contractors often interface with others in the execution of projects who have, at best, a rudimentary knowledge of geology and soil mechanics. Of course, there is a need for architects, bankers, and regulators, etc., but they typically do not have much interest in the nuances of geotechnical engineering, which relies on both art and science. Thus, significant time is spent educating counterparts in the need for comprehensive subsurface investigation programs and the intricacies of construction in the “dirt,” as they typically refer to soil and rock.

Jan 1, 2019

By Renato P. Cunha

The paper presents the results of a comparative and parametric analysis in which a numerical program developed exclusively for groups of deep foundations under general loading (vertical, horizontal and moment loads) was used. This program, developed in the doctoral thesis work of Zhang (2000), extends the finite layer method to accommodate a simultaneous general loading on top of piled raft foundations, allowing the establishment of a coupled relationship between displacements (in all three directions), rotations (in two directions), and external loads. Zhang (2000) has extensively tested and validated this program against well known case histories, but has not applied it to piled rafts overlying unsaturated tropical soil materials. Hence, this paper further explores the applicability of this program by using it to simulate the behavior of experimental field loading tests carried out at the University of Brasilia (UnB) experimental site. At this site, Cunha and Sales (1998) and Sales (2000) carried out several loading tests on small scale isolated rafts (1 x 1m) and piles (L=5m, dia=0.15m), group of piles (4 piles, raft clear off the ground) and piled rafts (1 and 4 piles underneath a raft in contact with the soil). The authors adopt Zhang&apos;s program to backcalculate, hence simulate, this series of experimental field loading tests under vertical loading. They also use this set of results to "calibrate" the program for further parametric analyses. The parametric analyses were carried out with different piled raft configurations in this same soil type, trying to evaluate their field behavior under the effect of distinct (geometric) configurations of pile distribution.

Jan 1, 2002

By Krishnendu Mandal

"For a multi-story building project in Kolkata, a pile load testing program was conducted to minimize pile performance uncertainty resulting from variable subsurface conditions and to verify the pile load vs. settlement response. The program consisted of performing five (5) instrumented load tests on augured cast-in-place (ACIP) pre-production test piles. Vibrating-wire strain gages and extensometers were installed in the test piles at strategic locations to enable measurements of the load vs. deformation behavior of the test piles. This paper presents a description of site subsurface conditions, test pile installation, instrumentation setup for a maintained load test (MLT), static compression pile load test results, and pile instrumentation result interpretation. Average mobilized unit shaft resistance values are calculated.2.0 INTRODUCTIONThe project site is located in Kolkata, near river Ganges, and the proposed development plans consist of constructing six (6)25-story (G+25) towers; see Fig. 1 and Fig. 2 below for approximate site location and proposed development layout, respectively. The buildings were designed to be supported on ACIP piles. A field load test program was implemented to verify sub-surface conditions and pile design. The test program consisted of installing Five (5) instrumented test piles numbered LP1A and B through LP6A and B, and performing static compression load tests on these piles. The piles were instrumented with vibrating-wire strain gauges and extensometers, so that the pile shaft resistance distribution along pile length and the pile toe resistance could be interpreted using direct instrumentation measurements."

Jan 1, 2015

By Daniel W. Mageau, Larry W. Applegate, Aaron K. McCain

"An innovative method of ground freezing was successfully tested to create a “dry” excavation condition for a new building foundation at a site in downtown, Miami, Florida. The subsurface conditions in Miami generally consist of very porous, weak limestone and sand with groundwater near the surface. Water flow through these materials can be very high. Dewatering is extremely restricted in Miami so deep below-grade structures are rare and expensive. A new, innovative method to allow deep excavations in dry conditions without dewatering involves the creation of a thick, temporary, frozen soil plug below the planned excavation depth across the entire site to cut off vertical groundwater flow during construction. Frozen soil is impermeable and very strong and has long been used for temporary structural and water-tight shored walls. Using the same proven principals, frozen soil plugs are very effective at cutting off water from the bottom of the excavation as well as resisting upward buoyant forces. This new freezing method can be used for fairly deep excavations in new building construction supported on deep foundations. The building piles act as temporary anchors for the frozen plug to resist very high upward buoyant pressures until the permanent structural slab is completed.IntroductionUnlike other Cities, below grade basements are rare in Miami. The few basement foundations constructed have utilized a cumbersome and expensive method of excavation and shoring involving underwater excavation, tremie slabs, and commercial divers. The key issue for underground construction in this area of the country is the vertical flow of groundwater through the base of the excavation. To deal with this issue in the past, the contractor first installed all of the building piles and the perimeter shoring walls. Then, interior sheet pile walls are installed to create small manageable excavation pits. Each pit is then excavated through standing water “in-the-blind” and around the buildings support piles. The final excavation, interior struts, and inspection is performed by commercial divers. Finally a thick foundation tremie slab is poured under water. This method could be successful but proved to be time consuming and expensive. In addition, some building piles were occasionally damaged during the under-water construction process."

Jan 1, 2015

By Ed Revoort, Robert Schippers

In Rotterdam in the Netherlands the project ‘De Zalmhaven’ is being developed. The project consists of the realization of houses, parking facilities, two residential towers of 70 m and a residential high rise of 215 m. An artist impression for the project is given in figure 1. For the high rise a new development in the use of large diameter, drilled piles with a steel casing has been successfully utilized. In this article the installation method of 65 m long steel drilled piles in two consecutive sections is presented. The settlements for the building (and the influence on its surroundings) have been analyzed in detail using 3D Finite Element calculations, which will also be discussed. Finally there is focus on the results of settlement measurements carried out during construction in relation to the settlement prognosis.

May 1, 2022