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By David J. Puller

As part of the value engineering process on a major Design Build highway project, instrumented trial pile load tests were used to achieve savings in cost and time on the foundations for a major river crossing. Two trial piles were tested close to failure load at 25MN. Following the interpretation of the pile load test results which included the determination of the ultimate shaft and base capacity, the mobilisation of the shaft and base resistance with pile displacement, and correlations with vertical effective stress and SPT profile, a revised design methodology was proposed. A 25% enhancement on commonly assumed ultimate shaft friction in Chalk was adopted. In addition a significant reduction in the Factor of Safety on end-bearing capacity generally used was also implemented. The revised design resulted in a significant cost and time saving on the piling operation with the pile length reduced by up to 6m (approx. 20%) for the river piers.

Jan 1, 2002

By Daiki Takano, Naoki Takahashi, Hidenori Takahashi, Ikuo Towhata, Yoshiyuki Morikawa

"The method in this study, in which cement-treated piles are installed into the ground to decrease the amount of liquefied lateral flow, has been studied. The authors are also investigating the most effective arrangement of piles to optimize cost-effectiveness. In their investigation, they propose shifting the position of the piles to prevent lateral flow in various directions. The present study conducted centrifuge model tests to clarify the improvement effect of piles against the lateral flow of liquefied soil and the effect of the pile arrangement. Then, numerical fluid analyses were conducted to consider the improvement mechanism. As a result, the model tests and numerical analyses showed that the pile improvement dramatically reduced the lateral displacement and that the average total flow velocity decreased in the irregular case.INTRODUCTIONLiquefied ground subjected to seismic motion loses its stiffness and strength, and lateral flow often occurs in sloping areas and backfill areas behind collapsed quay walls. In the Hyogoken–Nanbu Earthquake in 1995, the reclaimed island that was surrounded by collapsed quay walls expanded toward the sea and the amount of displacement reached a few metres (Hamada et al., 1996). Two countermeasures can be considered to guard against lateral flow: preventing liquefaction and reducing lateral displacement. The former method is ideal; however it is costly and time-consuming. Based on these considerations, the authors (Takahashi et al., 2013; Morikawa et al., 2014) are currently studying a method in which cement-treated piles are installed into the ground (see Fig. 1) to decrease the amount of liquefied lateral flow. The countermeasure cost using this method is relatively low because of the low replacement ratio. The authors are also investigating the most effective arrangement of piles to optimize cost-effectiveness. It has been proposed that the position of the piles should be shifted so that lateral flow can be prevented in various directions, as described in Fig. 2."

Jan 1, 2015

By Barry C. Roth

Driving of large piles in water can impact marine wildlife. Bubble curtains can mitigate these adverse effects. The procedures for and preliminary results of monitoring airborne, waterborne and groundborne vibrations with and without bubble curtains on a test project involving 2.438 m piles to 110 m is reported here. We observed fish kills and sea lions apparently fleeing the area. These phenomena were presumably due to the extreme acoustic effects of the powerful hammers which generated waterborne sound intensities locally in excess of 240 dB. This waterborne pile driving noise data collection undertaking is believed to be the most extensive ever attempted.

Jan 1, 2001

By Saba Mohan

This study presents results based on the Pile Installation Demonstration Project (PIDP) that was conducted as a part of the East Span San Francisco-Oakland Bay Bridge Seismic Safety Project. For the three full-scale pile installations, two different high-energy hydraulic hammers were selected for the installation. However, these hammers may not have sufficient energy to drive these large diameter piles at their ultimate capacity following long-term set-up. Nevertheless, these hammers were selected because, soil plug behavior, the generation of excess pore pressures and remolding of soil during driving were expected to reduce the shaft and end bearing resistance, and therefore reduce the energy required to drive these piles to design penetration. Data collected during continuous installation driving and after a series of re-strikes at different set-up times ranging from 1 to 33 days were used as input data for CAPWAP. These results were used to estimate the soil resistance along the pile length and at the toe of the pile, and the soil pile set-up behavior. Validity of the procedures used to predict the soil resistance to driving and predicted blow counts were verified with the field observed blow counts and the energy that was delivered to the pile. Based on combined CAPWAP analyses, the soil pile set-up with time was estimated and compared with results of other methods currently available in the literature for predicting the soil pile set-up rate.

Jan 1, 2002

By Jim Bruce, Naresh Gurpersaud

"The West Toronto Diamond project, under construction since 2006 and due to be complete in 2015, is a rail-to-rail grade separation project in the heart of urban Toronto. Once complete, a depressed corridor over 1000 metres long will take the CN tracks beneath the CPR tracks. An interlocking steel pile wall serves to retain ground and cut off groundwater. Remedial measures, constructed using jet grouting, were required at several locations within and behind the steel piles.At mechanical interlock joints damaged or suspected of being damaged, jet grouting was used to improve native soils on the retained side of the wall to reduce permeability of the soil mass in intimate contact with the joints to 10-7 cm/s. At a number of steel piles where groundwater and soil type combined to cause basal instability inside the pipes during the interim between excavation and concreting, jet grouting was used to construct temporary bottom seals. At locations near adjacent structures where the steel pile installation process resulted in disturbed ground on the retained side of the wall, jet grouting was used to strengthen and stabilize ground.This paper outlines the details of the various jet grouting applications, the respective testing programs implemented to demonstrate in situ permeability and strength of the soil-grout matrix, and performance of the constructed system.INTRODUCTIONThe West Toronto Diamond (WTD) is a junction of several railway lines, all intersecting at the same grade (Figure 1). A major grade separation project at this site commenced in 2006 and is scheduled to be completed in 2015. The whole of the work is comprised of multiple contracts, completed and/or ongoing, by different constructors. Once completed, a depressed corridor over 1000 metres long with over 23,500 m2 (face area) of retained earth will bring the CN tracks beneath the CPR tracks and eliminate a major bottleneck at the most heavily used rail crossing in Canada."

Jan 1, 2017

By Jorj Osterberg

550 load tests of up to 150 MN have been completed on driven and bored piles using the Osterberg Load Cell. Because the test measures side shear and end bearing separately, much can be learned about the forces on the pile as it is loaded to ultimate capacity. At working loads side shear almost always far exceeds end bearing, with the distribution of shear and bearing greatly affected by disturbance occurring during drilling operations. Since much less movement is required to mobilize side shear than end bearing, most of the bearing develops after the working load is exceeded. Thus with insufficient bottom cleaning, safety against excessive settlement can be considerably reduced. Improved methods of drilling, hole cleaning, rebar cage installation and concrete placement are discussed. For rock socket piles it has been found that the ultimate test load far exceeds the working loads in most cases. This is almost always due to greater penetration into the rock than is required for adequate safety against excessive settlement. Factors affecting rock socket capacity are discussed. Increase of side shear and ultimate capacity with time is discussed. Case histories for driven and bored piles in soil and rock sockets are described.

Jan 1, 2001

"1.0 DESCRIPTIONThis work consists of furnishing all necessary labor, equipment, and materials to install prefabricated vertical (wick) drains in the ground in accordance with the Plans and as specified herein.2.0 REFERENCED CODES AND STANDARDSASTM D4716-08 Standard Test Method for Determining the (In-plane) Flow Rate per Unit Width and Hydraulic Transmissivity of a Geosynthetic Using a Constant HeadASTM D4632-08 Standard Test Method for Grab Breaking Load and Elongation of GeotextilesASTM D4533-11 Standard Test Method for Trapezoid Tearing Strength of GeotextilesASTM D4491-99a Standard Test Methods for Water Permeability of Geotextiles by Permittivity (2009)ASTM D4751-04 Standard Test Method for Determining Apparent Opening Size (A.O.S.) of a GeotextileASTM 6918-09 Standard Test Method for Testing Vertical Strip Drains in the Crimped Condition3.0 QUALIFICATIONSThe Contractor shall have successfully completed a minimum of five wick drain installation projects in similar ground conditions, and installed not less than 5,000,000 linear feet (1,525,000 linear m) of wick drain in the past five years. The Contractor shall have a minimum of five continuous years of wick drain installation experience."

Jan 1, 2014

By Adnan A. Malik, Tadashi Maejima, Jiro Kuwano

"The use of steel screw piles has greatly increased in recent years because of the advancement in the installation mechanism and its performance under compressive, uplift and lateral loads. In a steel pile system, the strength of pile material limits the end bearing resistance of the pile due to strong subsurface conditions. The installation mechanism of screw pile can reduce the end bearing resistance due to the torque and axial force. However, if the installation mechanism does not reduce the bearing resistance of the pile, another important factor that can reduce its performance is the strength of the helix/wing plate. In this study, the effect of wing plate deformation on the performance of single helix/wing plate pile bearing resistance investigated. A model ground was used to investigate the effect of wing plate deformation. Dry Toyoura sand was used as a ground material and was compacted to denser states of 80% and 92%. The shaft and wing plate material of the pile was the same to actual piles that are used nowadays in Japan. A series of load tests were performed with different wing plate diameters and thicknesses. It was observed that deflection in the wing plate reduces the bearing resistance of the pile. The increase in the thickness of the wing plate was seen to restore the reduced pile resistance due to deflection. It was also observed from the experimental results that the ratio of wing plate diameter to shaft diameter (Dw/Ds) greatly affects the deformation of wing plates, which ultimately affects the end bearing resistance of the pile. The results obtained in this research suggest that the outstand length (Lw) of wing plate should be less than 5.6 times the thickness of wing plate for piles having a large Dw/Ds ratio under strong ground conditions.INTRODUCTIONThe first use of screw pile was almost 180 years ago by Alexander Mitchell. He patented his invention in 1833 with the name “Screw Pile”, and used it for ship moorings. The use of screw piles has since been adopted in various areas such as lighthouses, fencing for agriculture and marine structures. The use of screw piles in civil works started in 1985, after the invention of the hydraulic torque motor, as it eases the installation process. Nowadays, screw piles are used in the foundation of transmission towers, elevators, buildings and many other civil structures.Screw pile has an edge over other steel pile systems due to its high bearing, uplift and lateral resistance. The end bearing resistance of screw pile depends on installation, strength of subsurface material and the pile material. The screw pile is installed by applying torque and axial force. The pile torsional strength should be more than the applied torque and axial force to avoid deformation before reaching the final depth."

Jan 1, 2015

By Jeff Hopple

"Bluestone Dam in Hinton, W.Va., along the New River, is owned and operated by the U.S. Army Corps of Engineers (USACE). Completed in 1949, the dam is 165 ft (50 m) tall, 2,048 ft (624 m) wide, and encompasses a water shed that is 4,600 sq mi (11,914 sq km). The Bluestone Dam Safety Assurance (DSA) Program began in 2001, and is a multiple-phase construction project to upgrade the capacity and stability of the structure to meet the probable maximum flood event. Installing 216 high capacity rock anchors was a major feature of the work.The USACE selected Brayman Construction Corporation to perform Phase 2B of the construction modifications to the Bluestone Dam. Brayman was responsible for installing the high capacity rock anchors, which range in size from 3 to 61 strands and have a design load up to 2,145 kips (9,541 kN). Drill holes range in size from 6.5 to 15 in (16.5 to 38 cm), and required full length corrosion protection. Of the 216 anchors, 57 were installed on top of the dam to resist overturning and the remaining 159 were installed on the face of the dam at a 45-degree angle to resist sliding.To gain access to the face of the dam anchor locations, the project required dirt benches, excavations with temporary shoring, and steel platforms. To access anchors on the east and west abutment faces, the team excavated over 10,000 cu yds (7,645 cu m) of material. Support of these excavations included the design and installation of three soil nail walls with over 145 nails and 3,500 sq ft (325 sq m) of shotcrete. The project also called for a 780 ft (237 m) long steel platform to gain access to the spillway anchors. The Stratus Group designed the platform to support two 85 ton (80 tonne) crawler cranes and as many as five drill rigs that were the equivalent to a design load of 3.5 ton per sq ft (335 kN per sq m). Once the final platform design was approved, fabrication of roughly 3 million lbs (1,360 tonnes) of structural steel began. Brayman’s in-house fabrication shop, in conjunction with Dura-Bond Industries and Advantage Steel, collaborated to fabricate and install the platform in less than five months. Flexibility in the platform design allowed for sections of the platform to be lowered as much as 16 ft (4.9 m) to provide access to anchors at lower elevations along the spillway face. In addition to the main spillway platform, Stratus Group, Brayman, Dura-Bond and Advantage designed, fabricated and installed six other unique platforms to facilitate anchor construction on various areas of the dam."

Jan 1, 2014

By Mark Johnson, Mathew Janes

"The Resonator RD 260 Resonant Pile Driver delivers ground disturbance free, high production pile driving. The Resonator has recently been used on numerous production pile driving sites in the Netherlands and Melbourne, Australia to drive piles in sensitive areas where conventional pile drivers could not be used. Two case histories are provide in this paper which demonstrate the features and benefits of Resonant pile installation.. In the Netherlands the Resonator RD 260 was used at the Vopak Oil Storage facility in the Port of Rotterdam to install pipe and sheet pile within an active pumping gallery. The site demanded vibration free pile installation to construct a cofferdam within sensitive, highly valued assets. Access was an issue and schedule demands were stringent as shutdown windows were narrow. The RD 260 provided ground disturbance free piling immediately adjacent to fragile structures. At Vopak the only site access was using a large crane positioned over 40 m from the location of pile driving. Driving was conducted amongst 900 mm dia pipes carrying heated crude oil.In Melbourne the RD 260 was used to drive GU 18 sheet piling adjacent to light rail easements. The project was the first of many grade separations being constructed within Melbourne urban areas to lower the light rail and provide quieter rapid transit. The original trial used an RGT MR105 series vibrator but noise and vibration criteria were exceeded. The RD 260 was brought in for a trial and performed with high production and produced negligible ground vibration. Up to 17 sheet piles 14 m in length were driven in a 2.5 hour window during the trial.IntroductionThe Resonant Pile Driving method is gaining acceptance around the world as a new method to rapidly drive piles free of ground borne vibrations. The high frequency vibrator resonates the pile, essentially turning the pile into a spring, to excite the toe of the pile with high accelerations and low amplitude. High acceleration with low amplitude generates high penetration rates but the high frequency stress waves are quickly dissipated in the soil. Typically ground borne vibrations are measured at below 1 mm/sec within 1 to 5 m of the pile. The Resonant method can drive a pile next to a glass of wine, without spilling, as has been demonstrated on numerous piling sites.How Does Resonance Work?The Resonant method uses a hydraulic piston - cylinder geometry to generate high magnitude, high frequency oscillating force. This is a very different mechanism than the eccentric mass technology used in conventional and variable moment vibrators.A unique valve geometry achieves the high frequency flow switching necessary to oscillate the hydraulic piston at up to 180 Hz (10800 VPM). The valve is controlled electronically for maximum accuracy of the desired frequency. The volume of hydraulic oil delivered through the valve to the piston (flow rate) determines the amplitude while the hydraulic pressure determines the peak force."

Jan 1, 1900

By Michael D. Justason

"In January 2009, long-time competitors, Anchor Shoring & Caissons Ltd. of Toronto and Bermingham Foundation Solutions of Hamilton, joined forces to tackle one of the Greater Toronto area’s largest deep foundation projects: the West Toronto Diamond Rail Grade Separation. The two companies formed the “West Diamond JV” and succeeded in winning the contract from the Canadian National Railways. This deep foundations work was the first and most significant part of the $300-million-plus rail grade separation project. A big part of the job turned out to be dealing with local government regulations and citizens’ concerns with noise and vibration.The project is approximately 10 km (6 mi) northwest of downtown Toronto in an area of mixed-zoning including light industrial, commercial and residential buildings. The area is commonly called the “The Junction,” because of the heavy rail- traffic. The “West Toronto Diamond” refers more specifically to the railway junction where the North-South tracks of Canadian National (CN) Railway meet at a level crossing with the East-West tracks of the Canadian Pacific (CP) Railway. The goal for this part of the project was to convert the West Toronto Diamond into a grade-separated junction by depressing the CN lines under the CP lines, thus allowing commuter rail carrier, called GO Transit, intercity carrier VIA Rail, and CN freight trains to pass through the new underpass.Dawn Tattle, president of Anchor Shoring & Caissons says, “not only is the site in a densely populated area adjacent to homes and businesses, the crews worked adjacent to active rail lines with numerous trains passing daily. During the 7-hour working day, approximately 60 trains passed through the site in very close proximity to working crews.” Safety was paramount. While trains were passing through the site, it was a railroad requirement that all equipment and men stop working. In addition, at those times, all personnel were required to stay 6 m (20 ft) from the tracks and were required to face the tracks. For the faster commuter trains, this work interruption could last as little as 2-3 minutes, while interruptions caused by the slower freight trains could last as long as 25 minutes. The most disruption to the site occurred during the morning commute between 7 to 9 a.m., so work did not really get underway until after that time. Once work finally commenced the race was on to finish as much as possible before the afternoon commute – hence the shortened work day. The amount of disruption caused by the trains was a big unknown faced by the JV going into the project, but crews adapted quickly to the very unusual work environment"

Jan 1, 2012

By Ahmed Elmekati, Frederick C. Rhyner, Steven R. Lowe

"The current phase of the Pacific Park development (formerly, Atlantic Yards) in Brooklyn involves constructing buildings on a platform over an existing LIRR rail yard. To preserve the maximum amount of space in the already congested yard and protect the yard which remains in service during construction, high capacity foundations are being designed well above previous capacities in the area. In addition to spread footings and small mats, various diameters of drilled piles are being used at design capacities ranging up to 600 tons. The piles are generally grouted at low pressure, up to about 50 psi. Load tests for various drilled elements, including piles, tiedowns and soil anchors, have confirmed allowable side resistance (bond) stresses in dense sand ranging from 20 to 30 psi. Testing with different rigs and operators has shown that down-the-hole hammers are feasible, but the installation techniques, types of equipment and size of the pile make a significant difference. The results show that more cost-effective foundations are possible when ample testing confirms expectations.I INTRODUCTIONThe Long Island Rail Road has operated a mainline on Atlantic Avenue since the 1800s, with a terminal at the intersection of Atlantic and Flatbush Avenues. In the early 1900s, the mainline was reconstructed in a cut and cover tunnel section. The LIRR’s Atlantic Yard was constructed circa 1908 to service the terminal. It was depressed about 25 feet below street grade to coincide with the LIRR’s mainline tunnel under Atlantic Avenue. Record drawings indicate that the gravity retaining walls lining the perimeter of the yard and other ancillary structures had been designed for an allowable bearing pressure of five tons per square foot (tsf). Perhaps by coincidence, the mat foundation for the tower of the Williamsburg Savings Bank was also designed for five tsf in 1929.Figure 1 shows a typical geologic section through the site. The geology and subsurface conditions in this part of Brooklyn consist of fill generally five to 20 feet deep underlain by dense to very dense sand and gravel; in places, with numerous cobbles and boulders which make pile installation challenging. The sand strata that are on the order of 150 to 200 feet thick were laid down by glaciers during the last ice age and have been heavily precompressed. The sand strata are underlain in places by remnants of the Cretaceous-era Raritan Clay formation and Fordham Gneiss bedrock. Because of this, the sand strata generally provide excellent support for shallow foundations and the allowable bearing of five tons per square foot is usually easily justified."

Jan 1, 2016

By Kevin Cunningham

"Litigation resulting from neighboring structures with settlement and/or lateral movement or improper pile design and faulty soils engineering analysis, are a multi-faceted opportunity for law firms. These types of claim scenarios are an attorney’s dream, and can obliterate a Deep Foundation Contractors profit and more importantly, can be avoided with a progressive approach to risk management in design and project management.The following (4) case studies will be examined and dissected to discern certain lessons learned for risk management solutions to avoid these deep foundation related challenges in the future.1) Pipe Flotation – Soil Conditions Not Anticipated in Specifications or Contract2) Easement Encroachment – Easement Dimensions Not Recognized Until Completion of Project3) Subjacent Lateral Support – Neighboring Structure Wooden Pile Unprotected Causing Structure to Settle4) Improper Pile Placement - Construction & Design Caused Retail Store to SettleSpecific Deep Foundation project challenges involving: buoyancy calculations regarding subsurface soil characteristics, design factors taking existing subsurface sewer line easements into account, structural instability as result of excavation causing exposure/heavy rainfall to existing wooden piles supporting adjoining building and improper pile location resulting from faulty pile design will be described with risk management recommendations to avoid these challenges in the future.From the very start of construction on any project deep foundation and excavating work poses numerous engineering and technical challenges for developers, contractors and engineers. Dealing with changing or hidden conditions is one of the most difficult challenges facing any contractor or engineer on a project. Relying on incomplete or inaccurate engineering reports is another common problem. Other challenges include dealing with technical errors or oversights that are deeply embedded in the project specifications or bid process.No matter what is the origin of the problem or how it manifests, deep foundation contractors, design professionals and engineers should be ever-mindful of good risk management practices that can prevent serious disputes that can result in costly litigation."

Jan 1, 2015

By Alan Quiroga

Nestled between Meridian Park and Howard University in the heart of Washington, D.C., the historic block between 14th, V and W streets North- west featured several original struc- tures, many of them dating to the 1800s. During its rich history, this square block has been home to a variety of different organizations including automobile showrooms and repair businesses, a parking garage, various industrial warehouses, and, in recent years, the headquarters of the renowned D.C. nonprofit Martha's Table. The revitalization of the buildings in this block also known as the Collection 14 project involved the transformation of aging and historical structures into a new multi-use development. The redevelopment project was distinguished by the retention of period street-facing building facades (to the extent possible) to preserve the character and culture of the historic neighborhood while revitalizing the block with some modern construction elements. The complexity of the project and difficult subsurface conditions required specialized and extensive sheeting, shoring and underpinning work to be performed. This project had many parties involved, including: • • • • Owner: Madison Investments Owner's representative: Compass Design & Development General contractor: McCullough Construction Civil engineer: Vika Capitol Structural engineer: Ehlert Bryan Architect: Perkins Eastman DC Geotechnical engineer: GEI Consultants Sheeting and shoring contractor: Steele Foundation

Aug 1, 2023

By John Y. L Chen

This paper presents full-scale instrumented pile static compressive and tensile load tests to be conducted in the area of Pearl Harbor, Hawaii. Thousands of piles have been installed to support the existing piers and wharves in the Pearl Harbor area. Due to the absence of bedrock within practical depths, most of the piles use combined friction and end bearing. A new 925 feet (282 meters) long and 50 feet (12 meters) wide reinforced concrete wharf supported on pile foundation is planned. This paper will present results of soil investigation, laboratory testing, dynamic load tests during indictor pile driving and static pile load tests. The subsurface conditions consist of soft harbor sediment, young alluvium deposit, volcanic tuff rock formation and stiff old alluvium deposit. The load test piles consist of 20-inch (508 mm) square and 24-inch (610 mm) octagonal pre-stressed, pre-cast concrete pile and instrumented with embedded strain gauges. The length of the piles ranges from about 50 to 125 feet (15 to 38 meters). The test pile program consists of probing, driving indictor piles, dynamic load tests during indictor pile driving and static load tests. The standard loading procedure method was used during static pile load tests.

Jan 1, 2002

By Armin W. Stuedlein, Jim Zammataro, Bernie Hertlein, Daniel Belardo, Qiang Li, Antonio Marinucci

"An experimental program focusing on four drilled shafts was conducted to determine the effect of high strength steel reinforcement bars on lateral resistance, steel casing on axial and lateral resistance, and steel casing without internal reinforcement on lateral resistance. Thermal Integrity Profiling (TIP) Thermal Wires and crosshole sonic logging (CSL) access tubes were installed in each shaft, and thereafter the corresponding non-destructive testing (NDT) was performed on each shaft to assess the integrity of the shafts and to compare the results from the different NDT methods. The results of the CSL tests using scored PVC tubes are compared against those conducted in 73/56 fully-threaded steel hollow bars, whereby the results indicated that the threaded bars served as a good host for performing the CSL tests. The data from the TIP Thermal Wires is compared against the results from the CSL tests for each of the four shafts, and the similarities and discrepancies between the two methods are discussed. This paper will serve as a reference to those interpreting the measurements and data obtained by performing nondestructive integrity tests on drilled foundations.INTRODUCTIONNon-destructive tests (NDTs) embody a set of critical tools for the evaluation of the integrity of constructed deep foundations, particularly for cast-in-place foundation elements. Construction defects may require the rejection of the foundation element by the owner’s representative, resulting in costly repairs or replacements and delays to the project schedule. The use and appropriate interpretation of the results from the NDTs provide the information required when evaluating the integrity of these constructed elements. A cooperative research program was conducted to assess the effects of various construction variables on the axial and lateral performance of drilled shaft foundations, which provided an opportunity to compare the established Crosshole Sonic Logging (CSL) test method to the newer Thermal Integrity Profiling (TIP) Thermal Wire method. This paper presents an overview of the experimental program performed at the geotechnical test site at Oregon State University (OSU), details of the CSL and TIP installation and testing methods, and the results of the NDTs on the constructed drilled shafts. Because one of the shafts was constructed with fully-threaded longitudinal steel hollow bars, this experimental program also allowed the assessment of the use of the hollow bars as access tubes for the CSL tests. Both the CSL and TIP test methods indicated that the shafts were of good quality and free from defects or anomalies; the data obtained using the TIP method also provided an estimate of the as-constructed shaft diameter and the reinforcement cage alignment, which will prove helpful when back-calculating axial and lateral load transfer during future loading tests."

Jan 1, 2016

By Jacob A. Jordan, Rachel M. Garrett, W. Robert Thompson III, James C. Pegues

"Environmental control structures for an existing fossil-fuel power generating plant near Pascagoula, Mississippi faced several design and construction challenges due to space limitations. Conceptual design calculations indicated drilled shaft foundations would likely be needed to accommodate the higher lateral and compressive loads expected under some structures. A maximum drilled shaft diameter of 60-in was preferred due to various space constraints. Smaller diameter drilled shafts were deemed acceptable under structures with more moderate loading conditions. Furthermore, augercast piles were considered where lateral loading was not a governing design criterion.A series of SPT borings and CPT soundings revealed a subsurface profile consisting of soft to firm clays to depths of about 25 feet, underlain by fine to coarse sands. The apparent relative density of the sands was loose just below the clay, with increasing density noted with an increase in depth.Analysis of conventional drilled shafts indicated needed capacities could not be achieved unless shaft lengths exceeded 100 feet. Post-grouted drilled shafts were therefore evaluated to decrease shaft lengths by taking advantage of increased base capacity. Analyses showed the higher predicted capacities needed for some structures could be achieved with this approach. Final design for the project incorporated 90-ft long, 60-in diameter post-grouted drilled shafts; 60-ft long, 48-in diameter post-grouted drilled shafts; and 60-ft long, 48-in diameter conventional shafts. Both post-grouted and conventional trial shafts were installed as part of the detailed design phase of the project. Each trial shaft included CSL integrity testing and Osterberg-cell bi-directional load testing. Load test results revealed that additional base capacity was, in fact, achieved through the post grouting process. The 60-in diameter post-grouted production shafts and the 48-in diameter conventional production shafts have been installed at the site, with the project that would utilize the 48-in diameter post-grouted shafts deferred at this time."

Jan 1, 2015

By Gianni O. Chieruzzi

A 400 MW, gas-fed power plant on floating piles and piled raft foundations was constructed in the Province of Moskovskaya, Russia in 2008. The subsurface is characterized by fill underlain by loose to medium dense alluvial deposits, with peat and clay interbeds, a stiff to hard, highly plastic, silty clay stratum of glacial origin, and a stratum of very dense, varved interbeds of sand and silt. More than 800, drilled concrete piles were constructed at the site. The pile length ranged from 15 to 23 meters below existing surface grade, and the pile diameter ranged from 0.9 to 1 meter. Initial analyses by others predicted total power plant settlements of 3 to 4 cm when subjected to the permanent loading conditions. Under a peer review process for the equipment supplier, subsurface investigation and testing were performed to verify the consolidation parameters used for foundation design of the power plant foundation. The parameters obtained in this investigation were used in the 3-D finite-element model ELPLA as inputs for the settlement analysis of the turbine building and power island. The ELPA analyses predicted settlements on the order of 7 cm over a period of 30 years. The actual settlements after two years of monitoring were compared against the model predictions. The rate of settlement and the recompression index were both underestimated in our model. The measured settlements have enabled us to calibrate both of these model parameters so that the model better matches the data.

By Alireza Ayoubian, Douglas S. Roy, Gianni O. Chieruzzi

"A 400 MW, gas-fed power plant on floating piles and piled raft foundations was constructed in the Province of Moskovskaya, Russia in 2008. The subsurface is characterized by fill underlain by loose to medium dense alluvial deposits, with peat and clay interbeds, a stiff to hard, highly plastic, silty clay stratum of glacial origin, and a stratum of very dense, varved interbeds of sand and silt.More than 800, drilled concrete piles were constructed at the site. The pile length ranged from 15 to 23 meters below existing surface grade, and the pile diameter ranged from 0.9 to 1 meter.Initial analyses by others predicted total power plant settlements of 3 to 4 cm when subjected to the permanent loading conditions. Under a peer review process for the equipment supplier, subsurface investigation and testing were performed to verify the consolidation parameters used for foundation design of the power plant foundation. The parameters obtained in this investigation were used in the 3-D finite-element model ELPLA as inputs for the settlement analysis of the turbine building and power island. The ELPA analyses predicted settlements on the order of 7 cm over a period of 30 years. The actual settlements after two years of monitoring were compared against the model predictions. The rate of settlement and the recompression index were both underestimated in our model. The measured settlements have enabled us to calibrate both of these model parameters so that the model better matches the data.IntroductionA 400 MW, gas-fed power plant was constructed near Moscow in the Province of Moskovskaya in Russia.Figure 1 shows the general arrangement of the main structures, and the geometry of the piles supporting those structures."

Jan 1, 2017

By Takashi Enomoto

"The cement deep mixing (CDM) method has a wide range of applications, both on land and at sea. This paper describes the features of the equipment on CDM vessels engaged in maritime construction in Japan: the DCM No. 3 barge, the DCM No. 6 barge, and the DCM No. 8 barge. The DCM No. 3 barge is a large vessel with a mixing area of 5.7 m2. The design of the elevator of the deep mixing unit on the DCM No.3 barge enables us to conduct deep underground/ sea operations. This enables us to conduct mixing at depths of up to 52.6 m below the seabed and up to 70.5 m from the water surface. Additionally, since the tower is installed on the center of the barge, it has excellent stability. The DCM No. 6 barge and DCM No. 8 barge are mid-sized vessels with a mixing area of 4.6 m2. The DCM No. 6 barge was fitted in 2013 with energy conservation equipment and upgraded to an environment-friendly CDM barge. The energy saving upgrade used electric power, instead of hydraulic power, by inverter controlled alternating current motor for both mixing unit and main hoisting winch. This enables the using on effective use of regenerative power when the deep mixing unit is lowered. A feature of the DCM No. 8 barge is that it has an inclinable tower located at the bow section for elevating the deep cement mixing unit. Since the tower can be greatly inclined, the hull has a lower center of gravity and greater stability when the vessel turns. This also allows the vessel to pass below bridges and simplifies cruise preparations, outfitting and dismantling work.INTRODUCTIONThe cement deep mixing method (CDM method) involves mixing and stirring a cement-based solidifier into soft ground to rapidly bring the ground to the desired firmness. This method is used to suppress ground shear deformation, increase strength, increase slip resistance, and mitigate liquefaction and subsidence. It has been recently used in Japan in the construction of revetments at controlled waste disposal sites, both to boost the strength of the seabed and to prevent the seepage of waste matter and other pollutants. Undertaking CDM construction work at sea requires specially constructed marine construction CDM vessels. Since CDM construction at sea entails many more restrictions on working conditions than construction on land, the vessels themselves sometimes need to be modified. This paper will describe 1) the remodeling of the turrets and mixing machinery for mixing to great depths in deep water (DCM No. 3 barge with eight axes); 2) the upgraded of equipment on board CDM vessels after accounting for environmental considerations (DCM No. 6 barge with four axes); and 3) the use of a inclinable tower (DCM No. 8 barge with four axes)."

Jan 1, 2015