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By Osama A. Safaqah

Driven plate anchors can be used to hold in place large bridge caissons during floating construction. Their small size and simple method of installation make them a very cost effective alternative to other direct-embedment, gravity, and drag anchors. The geotechnical design of plate anchors involves the anchor geometry, embedment, drivability, and proof testing. This paper describes the experience gained with plate anchors used during construction of the new Tacoma Narrows Bridge. For this project, the anchors had to be driven in dense to very dense sands, and had to resist large forces from 7-9 knot currents.

Jan 1, 2013

By Steven D. Dapp

The use of base grouting (tip grouting) to enhance the axial capacity of drilled shaft foundations can achieve improvements in economy and reliability for many types of projects and soil profiles. Recent experiences on a range of different construction projects in the Southeastern U.S. illustrate the most attractive opportunities for utilizing this technique and some limitations of the method. The quality assurance provided by measurements obtained during post grouting the pile toe is another important aspect favoring its use; the base grouting is shown to identify weaker piles and provide a means of remediating some deficiencies so that increased foundation reliability is achieved. This paper provides an overview of the methods used to evaluate and design for base grouted shafts along with lessons learned from several case histories.

Jan 1, 2006

By Emad Farouz

The resistance of very dense glacial outwash formations consisting of sand, gravel and cobble formations can be quite high, and techniques for measuring the strength and deformation properties often cause engineers to underestimate the strength of these layers in drilled shaft design. More realistic measurements of this dense formation can be achieved with slotted steel casing pressuremeter tests. To minimize disturbance and achieve accurate measurements, drilling a pilot hole prior to probe insertion is necessary. Characterizing geologic formations that contain significant amounts of gravel and cobbles is challenging because of scale factor. Inserting a standard pressuremeter probe into this formation without damaging the membrane is difficult. This paper presents a case study for the IR-75 project in Dayton, Ohio, USA, where these dense materials were characterized using a slotted casing pressuremeter, optimizing design by providing more realistic properties of these materials.

Jan 1, 2006

By Marius B. Wechsler

A mathematical analysis is developed for the determination of the cases when HP-piles might be replaced by precast concrete piles. The analysis focuses especially on the "integral abutment-bridges" which are used on large scale in the Great Plains of the United States of America, The theoretical considerations are illustrated by a numerical example.

Jan 1, 1992

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 Richard Schmidt, Lijun Deng, Mohamed Abdelaziz, Weidong Li

Helical piles are widely used as a foundation supporting a variety of different structures. Understanding the axial behaviour of helical piles is required to confirm the engineering design. Helical pile research is often conducted in the field, but this method can be prohibitively expensive in some cases. Geotechnical centrifuge modeling offers an alternative method for the helical pile research and practice. A series of axial load tests of helical piles installed into cohesive soils were conducted on the geotechnical centrifuge at the University of Alberta. The objective was to investigate the effects of inter-helix spacing and soil strength on the axial behaviour of helical piles. Four types of aluminum model helical piles including one single-helix pile and three double-helix piles with various inter-helix spacing ratios were tested. Both compressive and tensile loading tests were conducted. All model piles were instrumented with multiple strain gauge stations. The clay had an undrained shear strength of approximately 50 kPa and 120 kPa. The test results indicate that there is a transitional failure mode between the two widely recognized failure modes, i.e., individual plate bearing and cylindrical shearing. The shaft adhesion was significantly reduced by the helix. Axial capacities were comparable to the field test results.

By Brain E. Ladd

A load test program was performed on two auger cast piles constructed in the Inner Coastal Plain geology of North Carolina. Both test piles were installed through Coastal Plain deposits and into underlying Piedmont residual soils; one test pile was embedded into partially weathered rock (PWR). The recommended 100-ton design load was confirmed by a test program that included instrumenting the piles with strain gages. The two piles performed differently during the load tests due to the effect of embedment into PWR. Loading Test Pile No. 1, which was not embedded into PWR, to failure at about 230% of the design compressive load allowed for evaluation of the mobilization of the ultimate shaft and end bearing resistances. Mobilization pile resistance was evaluated by comparing shaft and end bearing resistances to top of pile deflection (?) normalized by the pile diameter (D). For Test Pile No. 1, the ultimate average shaft resistance was achieved at ?/D of about 7.5% and ultimate end bearing resistance at ?/D of about 9.5%. Test Pile No. 2, embedded into PWR, achieved a ?/D of only about 4% at 200% of the design load and was not loaded to failure. Shaft resistance was mobilized at a different rate within each individual geologic layer, i.e. ultimate shaft resistance did not occur simultaneously for all geologic layers. As the available total shaft resistance was exceeded and end bearing mobilized, the unit shaft resistances reduced from the peak values. A modified Davisson offset using ?/D of about 6.5% appears applicable for evaluating the ultimate capacity of auger cast piles in the Inner Coastal Plain.

By Hal W. Hunt

Heavier loading and more efficient equipment is helping to keep driven piles competitive in America. Better Knowledge and testing of soils and support materials make it practical to use higher stresses; this is being strongly promoted by those directly concerned with timber, steel and concrete piles. Readily available point protection is increasingly used to assure penetration of piles without damage to full load bearing capability. Fabric drains are being installed with pile equipment to speed consolidation of soils. Sheet pile configuration has changed; production has been reduced largely because of imports. Dynamic checking of representative piles for load carrying capability is replacing conventional load testing of just a pile or two ? at much lower cost.

Jan 1, 1987

By Patrick J. Hannigan, Geir Veslegard, Frank Rausche, Rozbeh B. Moghaddam

A common type of deep foundation used in Norway to support bridge structures is the drilled pipe piles (piles) filled with concrete reinforcement after installation. The standard installation practice is the use of down-hole hammers. Complex geology and difficult subsoil conditions in Norway causes a high variability of soil and rock layers which in turn make for differences between actual subsurface conditions and those expected from geotechnical exploratory borings. This situation is strongly noted when the foundations are not fully socketed, and the rock layer is sloped. In this particular case, special testing procedures are required to assess the drilled pile base material and evaluate the rock-socket to ensure full contact between the foundation base and the rock surface. The local standard practice to verify the latter condition, consists of coring and visually evaluating the material recovered at the bottom of the drilled pile. This paper presents a case where the coring and visual inspection were not possible and alternatively the geological material encountered at the base of the deep foundations was evaluated using force-displacement measurements. Two 1016-mm (40in) diameter open-end drilled piles identified as P02-04 and P02-05 were tested and evaluated using in-situ force-displacement data prior to filling the piles with concrete. Test results showed an average displacement of 7mm (0.28in) corresponding to 35MPa (5.1ksi) stress level for P02-04, and 7.2mm (0.28in) corresponding to a stress level of 38MPa (5.5ksi). Based on testing results, both drilled piles were within the established material assessment criterion presented by the local authorities. INTRODUCTION This paper presents a case study in Norway where the material encountered at the base of an open- end drilled pipe pile (pile) was evaluated using force-displacement data. In the deep foundation industry in Norway, it is a common practice to install piles to support transportation structures. Once the piles reach the embedment elevation, and the pile base is assessed, these are filled with concrete. In projects where sloping rock is the supporting layer, and all nominal loads are supported by the pile base resistance, assessing the material encountered at the pile base to ensure full contact with the rock becomes critical. The local practice to make this assessment consists of the use of weighted tape, coring, or inspection cameras. However, similar to any other testing and evaluation methods, these come with their own limitations. The variability associated with the use of the weighted tape, accessibility for the coring equipment to complete a coring process, or the conditions at the foundation base such as murky water or thick drilling fluids could significantly impact the photo or video quality taken at the pile base. In such conditions, it is important to consider alternate testing methods to evaluate the material at the foundation base.

Jan 1, 2018

By Mario Carnevale, Myles Danforth, Michael Oakland

The cost and overall effectiveness of foundation design depends on a robust characterization of the subsurface geologic setting. It is common practice to formulate deep foundation design from subsurface geologic characterization based on boring programs. The confidence level of geologic characterization is directly related to that of geologic interpretations, which are based on the spatial sampling pattern of boreholes relative to the complexity of the geologic setting. This paper presents a case history illustrating issues that arise during pile construction from over-simplified geologic characterization, the challenging steps taken to improve the subsurface geologic model, and the effect of additional characterization efforts on the pile foundation program. The seismic characterization methods used include multi-channel analysis of surface waves (MASW) and seismic refraction.

By Eric S. White, Thomas J. Sabourin, Khuram R. Mohib

"This paper presents the challenges associated with the design and construction of a steel sheet pile cofferdam supported with one level of grouted anchors in clean to silty sand with gravel. The initial assessment of the subsurface conditions indicated loose to medium dense soil with intermittent dense to very dense layers with no occurrence of cobbles and boulders. Sheet piles were proposed to be installed to a depth of 24 m below the ground surface to limit dewatering requirements for the cofferdam. During sheet pile installation, refusal of piles occurred at multiple locations forming passages for increased flow into the cofferdam. Modifications were made in the design of the dewatering system as a result of the increased flow. Finite element modeling was used to select the necessary modifications to the dewatering system within the cofferdam. Wells were installed based on the findings of the numerical model. Model simulations showed good comparison with monitoring of the field installed dewatering system.INTRODUCTIONIt is necessary to consider the impact of the ground water, subsurface stratigraphy, strength, and drainage behavior of the soil for the design and construction of cofferdams. This paper presents a case history of the construction of a cofferdam in Northern Ontario, Canada. The project consists of the construction of a powerhouse, intake, and tailrace which will generate around 28 MW of renewable clean energy by diverting water from New Post Creek through a power house and discharge into the Abitibi River. The focus of this paper is the dewatering and excavation support required to permit construction of the powerhouse. The layout of the cofferdam is shown in Fig. 1. The cofferdam for the powerhouse is rectangular in shape with sheet piles on all four sides intended to be driven to the design toe El. 101 m. The east and west walls have a length of 46.3 m. North and south sides are 47.6 m long; and in addition, two cantilever sheet pile walls bound the tailrace on the west side and two cantilever walls were installed on the east for construction of the penstock inlet. The ground surface in the powerhouse cofferdam area, before commencement of sheet pile driving, was brought to El. 125; the ground then slopes up to the East, toward New Post Creek, and the site is bounded on the West by the Abitibi River. 186 pairs of sheet piles were used to create the cofferdam and cantilever walls. The deepest excavation is to elevation 114.4 m. Within the west half of the cofferdam footprint, the base of excavation slopes upward at 3H: 1V to facilitate the tailrace discharge into Abitibi River.SOIL STRATIGRAPHYThe cofferdam design was based on the geotechnical investigation conducted by AECOM (2014) which included two relevant boreholes near the powerhouse footprint. The ground elevation at the time of investigation varied between 131 to 129 m. The material observed to the full depth of investigation was comprised generally of coarse to fine sand and gravelly sand or a sand matrix with gravelly inclusions. Some intermittent layers of clay and silt intrusions were also observed. Generally the soils grade finer away from the river. SPT N60 values were recorded in two borings during the field investigation with values reported from 3 to 92. The in-situ conditions ranged from compact to dense with some loose and some very dense zones. Figure 2 shows the variation in SPT N60 values with elevation."

Jan 1, 2017

By Walter G. Kutschke

Four significant soil nail wall projects in the eastern United States were recently completed with a combined area of 175,000 square feet of finished shotcrete surface. These projects required the use of innovative design and construction methods in order to address various challenges, including slide-prone back slope materials, perched water, highly erodible rock materials, curved wall alignments, very tight construction tolerances and unexpected subsurface conditions. Special focus is given to issues such as bench excavation, soil nail installation methods, shotcrete mix design, anticipated shotcrete quantities, shotcrete nozzlemen qualifications and weather conditions, in order to provide a lessons-learned database for future soil nail wall design and inspector considerations. These projects also underscore the importance of design engineer and soil nail wall contractor qualifications as well as effective communication with the owner.

Jan 1, 2007

By Matthew Janes

Quality control procedures are increasingly important with today's higher capacity foundations and complex loading conditions. The need for a mobile, repeatable, nondestructive and economical load test method led to the development of an entirely new approach. The system described involves using solid propellant fuels to accelerate a reaction mass off the test pile. The force required to accelerate the reaction mass upward acts equally downward on the pile. Very high forces may be applied to the pile in a controlled, linearly increasing manner. The duration of the applied load is approximately 100 milliseconds. This rate of loading is slow enough to allow the pile and soil to react together as a composite rigid body. Pile/soil accelerations and velocities are low, typically 1 g and 1 m/s respectively. The effects combine to produce pile and soil response no longer dominated by the transfer of force via stress pulse (as with impact). Instead the pile force increases throughout the length of the pile, with pile top and toe stresses building in unison with time. This emulates the stress condition during static pile loading. Finally, state of the art instrumentation systems are used to obtain test data. Displacement is monitored directly using a laser datum and integrated receiver located at the centre axis of the pile. Force is also monitored directly using a calibrated load cell. Data is acquired and digitized using a 386 PC with user friendly software capable of producing load deflection curves and time histories in the field seconds after testing.

Jan 1, 1990

By Garland Likins

Where soil conditions are favorable, augercast piles have significant economic advantages, but they also have some uncertainty due to the in construction methods. To confirm structural integrity, static testing can be performed on a small sample of piles. Other Non-Destructive Evaluation methods like Pulse Echo are frequently specified for a large percentage of the remaining production piles. However, such NDE methods require testing the pile after the grout/concrete has hardened. If problems are found, then the repair or replacement can be relatively expensive. The confidence in the quality of these piles can be improved by automatically monitoring the grout pumped as a function of depth during the grouting phase of installation. If a low grout volume is detected, the pile can be redrilled and regrouted immediately while the piling rig is still in place and the grout still fluid. This considerably reduces remedial costs. To be effective, such installation monitors must accurately determine both grout volume and depth during installation and be rugged simple to operate. Such an equipment can be of great help to the installation crews. The assurance gained may reduce the need for subsequent NDE tests. The quality of inspection of driven piles depends heavily on the inspection personnel. While inspection is critical in a good installation, it is sometimes assigned a low priority. Inspection personnel in many cases are technicians with little pile experience. They may not understand the project needs or even how the pile driving equipment works. The task is often monotonous and any distraction makes accurate record keeping difficult. In some cases inspection is totally ignored for lack of qualified personnel. Electronic systems can automatically and accurately monitor driven pile installations and include documentation of certain hammer performance parameters. This paper describes equipment available and routinely in use for automated monitoring of both augercast and driven piles and demonstrates applications on typical construction sites. The paper also discusses benefits and limitations of the alternative NDE tests. KEYWORDS: Augercast Piles, Piles, Installation Monitoring, Pulse Echo Method, Integrity Testing

Jan 1, 1999

By Osamu Taki

This paper presents the system, the strength of column, the design concept, and the applications with four case histories from the past project as the general aspect of Geo-Column (trade mark of single soil-cement column by SCC Technology, Inc.). In the system, it shows the installation process and drilling/mixing tool with the mixing process. In the design concept, it shows how to design Geo-Column against the vertical and horizontal load. Finally, it shows the applications with four case histories, (1) building mat foundation, (2) isolated foundation on the pedestrian bridge, (3) bridge spread footing and slope erosion control wall in the channel, and (4) cut-off wall and shoring wall in the underpass roadway to the railroad.

Jan 1, 2000

By Larry Rayburn

In the spring of 1999, construction commenced on the new Steelers Football Stadium in downtown Pittsburgh, Pennsylvania. Richard Goettle, Inc. (RGI) was the successful bidder to install the specified augercast piles for the foundation package. Description - Pittsburgh Steelers Stadium The new stadium will house the Pittsburgh Steelers Professional Football Team. It is widely believed that if a team is provided with a modern playing facility, that a winning season will ensue (Not always the case). The new stadium location is on the north side of Pittsburgh on the Ohio River, and just downstream of the confluence of the Monongahela and Allegheny Rivers. The site is west of existing Three Rivers Stadium. The Three Rivers Stadium was built during the late sixties and housed both the Pirates Baseball and Steelers Football Teams. The Public Auditorium Authority elected to replace this outdated stadium with two new stadiums, one for each professional team. The landmark stadium was imploded in February of 2001.

Jan 1, 2001

By Bengt H. Fellenius

Session 2, Deep Foundation without Soil Excavation, has attracted no fewer than 22 papers dealing with subjects from soil improvement by grouting, injection, and deep mixing techniques through vibroflotation and special piles, including aspects pertaining to conventional driven and bored piles. In the short time available, it is not possible to both do justice to the papers and provide a critical review of the state-of-the-art. Instead, to meet the objective of making the next half hour worthwhile to the audience, I have chosen to comment on a few special points brought forward in the papers and thereafter to discuss more in detail a couple of aspects I have deemed to be of general interest. Four papers deal with jet-grouting, injection, and deep mixing techniques: DOMSKI, J. J. Reinforcement of subsoil under the foundations of historical buildings in Cracow using deep injection technique. RESTELLI, A. B, BERTERO, M., and LODIGIANI, E. Deep mixing technology to improve the bearing capacity of a very soft clayey soil under an earth embankment.

Jan 1, 1994

By Brian Isherwood

TransCanada Pipelines, Calgary (TCPL) is one of North America's leading transporters of natural gas through its energy transmission business. TransCanada also operates significant complementary businesses in energy marketing and energy processing in North America and internationally. The main trunk pipeline crossing Canada comprises as many as six pipes, 30" to 48" diameter delivering up to 7.8 trillion cubic feet of natural gas per day. To maintain the maximum operating pressure of 1000 psi, it is necessary to provide compressor stations at 60 to 100 km spacing. One such station is located at Potter, in northern Ontario, some 80 km north of Timmins, referred to as Station 102. The station contains two compressor plants, 'A' and 'B' Each incorporates a gas turbine driven centrifugal compressor unit. 'A' Plant uses an aero-derived gas generator (jet engine) rated at 15 MW (19,000 HP).

Jan 1, 1997

By Peter Chou

A total of 117 slope stabilization drilled piers were installed as part of a major hillside revitalization project. The 110-million dollar development, known as Stratford at Kenwood, included an 18-story upscale senior residential tower, a 3-story healthcare building, and 4-story condominium buildings, offering approximately 580,000 square feet of living space with panoramic views of Downtown Cincinnati, Ohio. In an effort to establish a flatter hillside plateau for the new 4-story condominium and to create a cut and fill balanced jobsite environment, an 800-foot long row of drilled piers and a 600-foot long multi-tiered shear key system was used to terrace existing 1.5H to 3H: 1V steep slopes and support the new fill. These slope stabilization features reduced the amount of spoils needed to be wasted off-site and mitigated the risk of slope instability. An ODOT/FHWA research indicated that spacing of stabilization piers and necessity of top-connecting elements are highly dependent on pier diameter, spacing, soil type, depth to potential failure surface, surcharge loads, and pier deflection. Due to pre-existing deep buried swales, various load combinations, and the complex mechanism of soil arching effects between adjacent piers, both analytical and numerical computer modeling was performed to estimate the loading on each pier. New generation multiplexed, 3-Dimensional, Micro-Electro-Mechanical-System based inclinometers were installed between selected piers to confirm the pier design, and monitor the fill placement, as well as long-term slope stability.

Jan 1, 2009

By Ryan Higbie, King Chin, Matthew Anderson, Mike Huggins, Rian Johnson, Dave Sinsheimer

"The Permanent Canal Closures and Pumps (PCCP) project is the capstone piece of New Orleans’ extensive hurricane risk-reduction system constructed following Hurricane Katrina. The project consists of three discrete pump stations and flood gates on the shore of Lake Pontchartrain which provide a storm surge barrier and pump rainwater from the City of New Orleans’ primary drainage canals. The depth of the pump station structures ranged between 39 and 45 feet below sea-level. USACE developed the PCCP project for design-build delivery; granting the project team latitude to develop innovative, cost effective solutions for the project. The use of OPEN CELLTM cofferdams to construct the pump station structures was one such innovation. OPEN CELL structures utilize the strength of the retained soil to anchor cellular sheet pile face arcs; allowing a free-field of construction within the cofferdam. This cofferdam design did not require ground improvement or dewatering around the perimeter of the cofferdam. The free-field cofferdams streamlined construction and large equipment installation within the structures with no encumbrance from internal bracing. Meticulous force-based design, soil-structure numerical modeling, and physical testing were all techniques used to present and gain USACE acceptance of the design on this vital element of the work.PROJECT DESCRIPTIONThe Permanent Canal Closures and Pumps (PCCP) project is the capstone piece of the City of New Orleans’ extensive hurricane risk-reductions system constructed following Hurricane Katrina in 2005. The project encompasses three separate pump stations and floodgate structures located at the mouths of three outfall canals (17th Street, Orleans, and London) on the south shore of Lake Pontchartrain. These three canals, running from the south to north, act as the primary conduits for discharging water from the New Orleans area. Prior to Hurricane Katrina, these canals were operated with pump stations two to three miles upstream of the mouths at Lake Pontchartrain. This left long stretches of levee on each side of the canals exposed to storm surges entering from the lake. Three levee failures occurred along these canals during Katrina; two at London Canal and one at 17th Street Canal. The failures resulted in major flooding of the surrounding neighborhoods, significant damages, and loss of life.Following initial canal levee repairs after Hurricane Katrina, USACE, in partnership with the Louisiana Coastal Protection and Restoration Authority (CPRA), took action to move the line of flood protection to the mouths of these three canals at the edge of the lake. By cutting off the storm surges from Lake Pontchartrain at the entrance to the canal, over ten miles of canal levee would no longer be exposed to storm surge water elevations, significantly decreasing the risk of failure."

Jan 1, 2017