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By David S. Graham, Paul J. Axtell

Crosshole Sonic Logging (CSL) non-destructive integrity testing identified anomalous readings near the base of a 6.5-foot diameter drilled shaft rock socket. The anomaly was confirmed to be a defect by subsequent coring and core hole camera inspection. A large void and exposed rebar were visually observed in one of the core hole camera inspections. The center of the shaft was then excavated initially with 3-foot diameter tooling and subsequently with 4-foot diameter tooling as part of the remedial actions to address the defect. While excavating with 3-foot diameter tooling, the shaft defect was not encountered. Excavation with 4-foot diameter tooling revealed the defect, a significant void around the majority of the shaft circumference. The void extended radially from the circumference of the 4-foot diameter excavation to beyond the reinforcement cage to the exposed wall of the rock socket around approximately 80 percent of the shaft circumference. CSL results and observations made during remedial shaft investigation and excavation are in good agreement. The shaft defect, located primarily outside of the reinforcement cage, was effectively identified by CSL testing. Although the defect was confirmed by investigative coring, the remedial excavation demonstrates how the investigative coring could have easily missed the defect. This paper shows how CSL results compare to physical observations made during a rare opportunity to characterize the full extent and nature of a drilled shaft defect originally identified as an anomaly by CSL testing. INTRODUCTION The case history presented here pertains to a drilled shaft for a multi-shaft bridge pier in the Midwestern United States. However, the observations presented in this paper are not a result of unique site conditions or the particulars of the project. The lessons learned from this case history are applicable to almost any drilled shaft constructed in the wet. The overall length of the subject shaft is 22 feet including approximately 12 feet of permanently cased, 7-foot diameter shaft extending to bedrock and approximately 10 feet of uncased, 6.5-foot diameter rock socket. The shaft is designed to resist axial and lateral loads and considers the contributions of side and base resistance in the axial design. Six, 2-inch diameter steel Crosshole Sonic Logging (CSL) tubes are include in the shaft. The bedrock at the shaft location includes beds of sandstone, shale, and limestone. The shaft was drilled using conventional drilling equipment and tooling, and water was used as the drilling fluid. Conventional drilled shaft concrete appropriate for underwater tremie-placement was placed via a 10-inch diameter open hopper tremie.

Jan 1, 2019

By Stephan Jefferis

It is my understanding that the Scandinavians have done some fundamental work on durability. I have seen a study published whereby the author, Helen Anderson, comments on the durability of polyurethane grouts and there was -if I am not mistaken- a reference made to another Scandinavian testing institute comparing durability of the polyurethane to cement grout under the same type of circumstances. Circumstances are important so we should actually ask the gentleman to shed some light on this particular method because apparently Scandinavia is the place where durability has been taken very seriously and has been well researched.

Feb 10, 2003

By Tai Luu, Michael McNicholas, James C. McIntyre

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

Jan 1, 2019

By Serhan Guner, Sundar Chiluwal

Although significant research has been conducted on helical piles, there is a lack of research and official design provisions on the helical pile-to-pile cap connections. These connections may govern the global response of pile cap systems—especially in tall and light structures where uplift forces dominate the response. To improve future industry practice, the objective of this study is to understand the influence of pile-to-pile cap connections on the global behavior of concrete pile caps and develop recommendations for their efficient design. For this purpose, 108 high- fidelity nonlinear finite element simulations are conducted to quantify the influences of bracket type, embedment depths, longitudinal reinforcement percentages, shear span-to-depth ratios, and loading conditions on the load, deformation, cracking, and failure behavior of concrete pile caps. The results indicate that the design configurations involving single bracket type may result in premature concrete cracking around the anchorage zones with a 25% reduction in the uplift load capacity. The investigations also confirm that high reinforcement percentages and low shear span-to-depth ratios result in higher load resistance in all bracket types, and that the load capacities of the double and studded bracket types are similar. For applications requiring the use of lower embedment depths, it is recommended that either double or studded bracket types be used. The research findings have applicability to both helical and micro piles given that both include similar connection types. INTRODUCTION Tall and light structures may experience significant uplift forces at their foundations due to large overturning moments from wind or other lateral loads. Helical piles (e.g., Fig. 1a) can provide a cost- effective, practical, and resilient solution for resisting significant uplift forces. In order to realize the full potential of helical piles, it is imperative that the helical pile-to-pile cap connections (see Figs. 1b, c and d for examples) are properly designed to resist the applied forces. However, there is a lack of research and associated knowledge on the influence of pile-to-pile cap connection detailing on the global response of pile caps.

Jan 1, 2019

By William H. Walton, Clyde N. Baker Jr., Darren S. Diehm

"A 51-story concrete core and steel frame commercial office tower was recently constructed on the site of the former US Gypsum building in downtown Chicago, Illinois, USA The structure foundation reused several caissons from the demolished US Gypsum building supplemented with new belled caissons bearing on silty clay hardpan. Extensive in-situ pressuremeter testing was performed during the geotechnical investigation to determine allowable bearing capacity and better estimate building settlements. Problems during foundation construction along the south side of the building frame required remediation of two caissons. One caisson was supplemented with micropiles, while the second caisson was abandoned and replaced with a straight-shaft rock socketed caisson. To determine the effectiveness of the repairs, the building foundation settlements were monitored during construction.IntroductionIn 2001, The John Buck Company began development of a new office tower at the southeast corner of West Monroe Street and South Wacker Drive in Chicago, Illinois. The site was formerly occupied by the 18-story US Gypsum (USG) building. Mr. Clyde N. Baker, Jr. (Senior Principal at STS Consultants, Ltd .) served as the foundation engineer for USG which was completed in 1962. The building was founded on a forest of belled caissons bearing at elevation -56 Chicago City Datum (CCD). For reference, the ground surface at Upper Wacker Drive is approximately elevation +20 CCD. The bearing material was a hard silty clay, locally described as Chicago Hardpan. The foundation caissons were designed using an allowable bearing pressure of 16 ksf (766 kPa). In 1996, the USG superstructure was razed, and the three-level basement was converted to an underground parking ramp.South Wacker DevelopmentThe 51-story high-rise building was completed in 2005 with a structural height of 681 feet (208 m), and an internal space of more than 1,000,000 square feet (93 ,000 square meter). The typical floor size is 27, 700 square feet (2, 570 square meter). Renderings of the building are provided in Figures 1 and 2. The largest single tenant is the accounting firm of Deloitte & Touche, which occupies roughly 45% of the building space with over 3,000 employees."

Jan 1, 2005

By Cassandra A. Wetzel

"Rock socketed mini-piles are a desirable foundation alternative when design capacity is more than 40 tons and there is limited access. In this case history mini-piles were designed to support between 75 and 200 kips at 12 locations adjacent to a perimeter wall, a party wall and at cast iron column piers. Limited geotechnical information, low overhead clearance, and active building population tested the creativity of the team to get the piles installed. The key geotechnical concern during installation of the mini-piles was the presence of a glacial till layer above the bedrock surface that restricted the seating of the casing into bedrock with a track mounted drill rig. Soil loss during the advancement of the rock socket using an air hammer was excessive and increased the risk of subsidence. Over a three week period the engineer worked with the contractor to modify the design, means, methods, and materials to install piles with adequate load capacity. This paper will present the changes in design and construction methods that were required.INTRODUCTIONRock-socketed mini-piles are a common and desirable deep foundation alternative to support loads more than 40 tons in New York City. Limited vertical clearance, accessibility, vibration control, and load capacity make this pile type attractive; it also does not require a static axial load test when socketed into rock. This added benefit makes this alternative all the more feasible.The installation of a drilled pipe extending to bedrock through a glacial till deposit presented challenges to the contractor and engineers to confirm the casing is seated sufficiently into the rock prior to drilling the rock socket. The loss of soil between the steel pipe and the till/bedrock interface can compromise the performance of the pile and soil loss can result in settlement of the ground surface.This paper presents the design and construction method changes made on one project during the installation of ten limited access rock socketed mini-piles."

Jan 1, 2017

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

Large diameter open-end pipe piles are increasingly used as deep foundations to support heavy onshore and offshore structures. During the driving process, several factors such as subsurface conditions, hammer type, hammer efficiency, pile type, plug conditions, temporarily increased base resistance, and loss of shaft resistance have direct impact on the driveability of large diameter open-end pipe piles. In a uniform subsurface condition, the unit shaft resistance increases with depth. Consequently, more resistance is accumulated as piles penetrate to greater depths which results in higher driving resistance. However, according to the friction fatigue analysis, the greater the number of shearing cycles occurring on a soil segment along the pile shaft, the greater the reduction of its shear resistance. As a consequence, since upper soil layers are subjected to a greater number of blows than those at greater depths, they have a relatively lower resistance compared to what would be calculated with standard geotechnical analysis methods. As a result of this progressive and nonuniform loss of shaft resistance with driving, blowcounts tend to increase at a lower rate than expected from traditional analyses. This paper discusses one of the approaches to the driveability analysis with the geotechnical friction fatigue consideration. It also shows comparisons between predicted driveability obtained from wave equation analysis and field driving records. All analyses were performed for a 2.134 m (7.0 ft) diameter open-end pipe pile installed at a total depth of 192.90 m (554 ft). Two separate static resistance and wave equation analyses were completed for the case study presented in this paper: 1) Friction Fatigue analysis based on the recommendations of Alm and Hamre (2001), subsequently referred to as the FF model, and 2) Standard Driveability analysis based on soil set- up factors, hereafter referred to as the SD model in this paper. Results from analyses included the shaft resistance distributions compared to the result of the signal matching analyses determined from the pile dynamic measurement. Furthermore, predicted blowcounts were compared to observed blowcounts during the pile driving. The comparison analyses indicated a 54.4 percent resistance loss of the Static Resistance during Driving (SRD) due to the geotechnical friction fatigue corresponding to a 46 percent reduction in total resistance. The analyses also showed that average predicted blowcounts using the friction fatigue were 6.4 percent lower than measured blowcounts, whereas, the standard driveability approach showed 42.1 percent higher blowcounts compared to the blowcounts shown in the driving log values.

Jan 1, 2019

By Frank Rausche

Without doubt, driven piles are the most economical deep foundation element for a nearshore environment, providing for high bearing capacities and stiffness, quick installation times, assured quality by simple monitoring and inexpensive dynamic load testing during restrike testing. However, when the pile top elevation is several meters below water surface, questions often arise as to the most reliable and economical pile installation method. Frequently encountered, yet relatively expensive, solutions include driving inside a dewatered cofferdam, driving long piles that are later cut off below water surface, or using an underwater hammer. Arguably, the most economical solution is driving the piles with a follower or chaser. However, many foundation engineers shy away from this solution because of the uncertainty associated with the transfer of energy through the interface between follower and pile, the associated potential driveability problems and maybe the limited fatigue life of the follower. This paper will demonstrate how the driveability of a hammer-follower-pile-soil system should be analyzed prior to installation and how to model the pile-follower interface both for steel and concrete piles. As an example, results will be presented which were obtained for both steel pipe piles and precast concrete piles, driven by a single-acting diesel hammer through a steel follower for a pre-construction test pile program in Venice, Italy. While analysis of the steel pile-follower system was straightforward, for the concrete piles, the presence of a soft cushion material whose material properties changed continuously posed some difficulty. Pile Driving Analyzer® measurements and CAPWAP® analysis yielded not only realistic stresses and transferred energy values in the pile, but also reasonable model parameters for further use in a pure wave equation analysis. As a side note for clarity, the dynamic measurements and analysis results herein presented are based on the GRLWEAP and CAPWAP software. GRLWEAP is commonly used all around the world for the preparation of pile driving jobs. The program either yields a bearing graph that relates bearing capacity and pile stresses to blow count or set per blow or it predicts blow counts and pile stresses as a function of pile penetration. These results allow the contractor to estimate driving time and select an economical hammer and driving system for a safe and efficient installation. CAPWAP on the other hand is the analysis of choice once a pile has been installed and records of pile top force and velocity have been acquired during installation or during a restrike test. CAPWAP is a signal matching program which calculates for one particular impact (for example at the end of driving) the static and dynamic soil parameters. Its final results include the calculated resistance distribution, the complete stress history in the pile and also a simulated load set curve. The CAPWAP calculated dynamic soil parameters can also be used in a Refined GRLWEAP analysis to generate a calibrated bearing graph."

Jan 1, 2006

By Peter J. Nicholson

The methods of reinforcement to be discussed in this paper are all insitu methods, ones that can be used on the soil structure as it exists in the ground, and do not rely on excavation and replacement of the soil. Current practice in the United States, as well as new ideas and methods, will be discussed as they relate to slope stability, retaining walls, and to other uses such as control of mine or cavity related subsidence and to liquefaction control under existing structures. The method is based on the concept of "nailing" or reinforcing the soil in place, and thereby causing a mass of soil to act as a coherent unit. When performed properly, a true gravity structure can be constructed, one that will remain intact under both horizontal and vertical loadings and that will also resist vibrational and seismic loadings.

Jan 1, 1991

Jan 1, 1991

By BRETTMANN TRACY

Jan 1, 2000

By Patrick J. Hannigan

The pile foundation designer typically performs a subsurface exploration program and static pile capacity calculations before selecting a pile foundation type, length, and capacity. During construction, a pile installation criterion must be established to meet these design requirements. This installation criterion usually consists of a minimum penetration resistance or blow count to confirm pile capacity and may also include a minimum embedment requirement. This text will focus on use of wave equation analysis and dynamic measurements to meet design requirements. BEFORE THE WAVE EQUATION Since the mid-1800s, over 450 dynamic formulas for pile driving control have proliferated. In their simplest form, these formulas relate hammer energy to the work of soil resistance, or simply: W ? h = R ? s (1) Where W = ram weight h = ram drop height or stroke R = pile capacity s = pile penetration per blow

Jan 1, 1990

Jan 1, 1988

The development of Augered Cast-In-Place (ACIP) piles started in the late 1940's when several projects were performed by Intrusion-Prepakt, Inc. utilizing various techniques to place the piling. On some projects, a grout pipe was placed down the augered hole after the auger was withdrawn, and structural grout was pumped into the hole until grout appeared at the surface, after which the grout pipe was withdrawn. In some instances coarse aggregate was placed after a grout pipe was in place, and then the grout was intruded into the coarse aggregate, making a pile using the preplaced concrete method. Another method of forming augered piles used a system of driving or drilling a grout pipe through soils adjacent to the auger once the auger was drilled to the bottom elevation. The tip of the grout pipe was placed in close proximity to the tip of the auger. As the auger was withdrawn, grout was pumped through the grout pipe filling the augered hole from the bottom. After grout was observed at the surface, the grout pipe was withdrawn. In 1951, a patent was applied for by Raymond Patterson describing the above techniques along with a technique for placement of grout using a hollow stem auger and a removable plug or lead bit at the tip of the auger. The expendable plug or lead bit was removed by using grout pressure. The patent was granted in 1956. Around this same time other augered piling con-tractors began operations under licensed arrangements.

Jan 1, 2003

By M. Melih Demirkan, Juan J. Gutierrez, Raghav Ramanathan

"As the capital of the United Arab Emirates (UAE), Abu Dhabi is one of the world’s fastest-developing cities. To sustain its significant growth rate, Abu Dhabi must surmount challenging engineering problems in the most efficient manner. One of the challenges facing Abu Dhabi is ground settlement caused by poor groundwater control practices in inherently difficult subsurface conditions. For construction projects in Abu Dhabi located near the Arabian Gulf, groundwater is frequently encountered and must be accounted for and addressed during design and construction. Abu Dhabi City CenterRecently, the Abu Dhabi government developed a geodatabase by digitizing, processing and qualifying an extensive amount of existing information (i.e., more than 26,000 borehole logs). Because of the evaluation and processing of the geodatabase, detailed maps of geotechnical and hydrogeological surface features were generated using 3D modeling. Ultimately, the geodatabase was used to develop risk maps indicating geohazards, such as sabhka (or salt flats), uncontrolled fill and cavities. This information identifies the location and extent of the areas vulnerable to surface subsidence. Dewatering can change pore water pressure, which, in turn, alters the effective vertical stress in a soil mass and can affect groundwater chemistry. Changes in pore water pressure and groundwater chemistry can significantly affect soil and rock. The potential effects of dewatering include:• Change in effective stresses and shear strengths in soils• Increase in seepage velocities and pressures• Erosion or transport of soil particles and piping• Settlement• Collapse of subsurface cavities or voids• Transport of groundwater containing contaminants• Dissolution of soluble materials, such as rock salt or gypsum"

Jan 1, 2017

By Masahiko Yamaki, Takahiro Yamanashi, Hijiri Hashimoto, Hirochika Hayashi

"In this study, the authors used heat conduction analysis with the aim of quantitatively evaluating whether treating improved ground with cover soil is an effective measure for maintaining strength development in the surface layer of improved ground after constructing cement treated soil for the winter season. This report describes a simple procedure to evaluate covering soil thickness, which is necessary for the strength of the surface of cement treated soil, by using the freeze index and both the water content ratio and dry density.INTRODUCTIONIt was reported that when ground improvement using cement is performed in winter in a snowy cold region (Fig. 1 photo, Fig. 2), the uppermost 1 m of the improved ground (i.e., the cement-treated soil) tends to become prone to solidification failure from exposure to the cold air during curing (Hashimoto et al. 2006). In light of this, our research laboratory conducted unconfined compression tests using curing temperature as a parameter of analysis on improved ground toward understanding the influence of curing temperature (ambient air temperature) on the strength improvement afforded by ground improvement.The authors found that if the curing temperature is maintained at 0°C for the first 28 days after improvement and then at 5°C for the next 337 days after improvement, the improved ground is expected to have 90% of the unconfined compressive strength of improved ground whose temperature was maintained at 20°C for the first 365 days after improvement (Hashimoto et al. 2011)."

Jan 1, 2015

Jan 1, 1992

By G. Ranjan

The designers and the practicing engineers have started using latest and cost effective techniques of ground improvements which utilise the weak and poor sub-soil deposits efficiently for the civil engineering construction. In the present investigation, a new concept of 'skirted granular piles' has been advocated. An effective method of construction of granular piles as an economical alternative to vibroflot, and the skirt has been developed. The construction technique is based on indigeneous know how which effectively utilises the man-power technology avoiding import of costly equipment suiting to the developing countries. Full scale insitu tests have been carried out at four sites, having different soil conditions, on virgin weak sub-soil, and improved ground by casting plain and skirted granular piles. Effectiveness of different types of skirt has been demonstrated through insitu tests. A simple analytical approach has been proposed to predict the ultimate pile capacity. The predicted values of ultimate capacity have been found to demonstrate a good correspondance. Granular pile behaviour in terms of pile depth, diameter, spacing and stress deformation characteristics of the improved ground have been discussed. A significant improvement in ultimate capacity in improved ground has been noted. This is further augmented when granular pile group is skirted.

Jan 1, 2010

By Franz-Werner Gerressen

New developments are required each day as our industry becomes more competitive. To improve performance, continue and to ensure future demands can be met. This requires the development of technical support systems that enable a more constant delivery and quality of installation of pile foundations and other applications. For example: assistance systems capable of relieving the machine operator of automating monotonous or repetitive operations. Real time installation control of the production process to manage quality control, or data transfer and reporting systems capable of keeping pace with the digital future. This paper will describe these new approaches and considerations required for these new developments. The paper also describes the equipment which is needed to execute the work under the various conditions and provides references herein. INTRODUCTION The success of a construction site is influenced by a number of factors. Selecting the most efficient and economic methods during the planning phase to defining the right direction. This means having multifunctional equipment available. To ease the usage of this equipment by the operator, uniform operation and control systems are essential. Systems like this can provide uniform handling procedure for more than 20 different installation techniques. Experienced operators are not always available. Therefore, to ease the start for beginners and to support training, numerous assistance systems were developed. This ranges from simple information for controls shown on the monitor avoiding misuse to systems which can partly automate the construction process. Regardless, the best equipment is not enough when the construction is not running smooth. The control system not only helps to organize and coordinate service of the equipment; moreover, it allows the operator to control the quality during the installation process reacting if needed. It allows process optimization as well as documentation which might be required for later negotiations.

Jan 1, 2019

By N. Aarthi, G. R. Dodagoudar

The improvement of soft clay deposits using stone columns is a well-established ground improvement technique in the western world. This technique has been well documented and has proper design codes for precise execution in the field. The sand compaction pile (SCP) method is a contemporary technique to stone columns and has limited literature related to the strength characteristics of the loose to medium dense sand deposits treated with SCP. The available studies on the SCPs installed in cohesionless deposits focused on the improvement by indirectly assessing the SPT-N values pre- and post-installation of the SCPs. The widespread implementation of the SCP technique in recent years has increased the need for a more direct evaluation of the improvement. Earlier studies in this regard have revealed that the available design solutions are based on the type of installation equipment, their working efficiency, and accumulated field data. However, it is found that there are no generic design codes for the direct estimation of the ultimate bearing capacity of the SCP improved cohesionless deposits. To meet the design requirement for the SCP treated ground, a series of experimental and numerical investigations are performed in the present study to arrive at a direct framework in the form of design charts based on the pressure-settlement response of the treated ground. The developed design charts give the ultimate bearing capacity (UBC) of the treated sand deposit for the known initial relative density (RD) of the deposit, spacing and diameter of the SCPs, size of the footing, and for the specified target unit weight required for the intended application. It is concluded that the design charts will be of preliminary use to the design engineers to directly evaluate the UBC of the SCP improved loose to medium dense cohesionless deposits as part of the SCP method of ground improvement. It is expected to have more field-scale experiments and in-depth analysis before implementing these charts for actual field execution.

Nov 1, 2022