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By A. Fisher

The use of thermal integrity testing to verify the quality of deep foundations has increased significantly in the UK and other world markets over the last 5 years. The introduction of distributed fibre optic sensing to this field has broadened the range of applications in which it can be deployed and the types of foundations which can be tested. This paper presents how fibre optic sensing technology can be successfully deployed in the construction environment the range of foundation techniques to which it can be applied. Alongside developments in the practical aspects of thermal testing, progress has been made in establishing assessment criteria which can be used to evaluate the results. This paper presents recent examples of comparative studies on foundations which include both thermal integrity testing, cross hole sonic logging and intrusive coring. The use of distributed strain measurement during pile load testing presents an alternative means to verify the assessment criteria used for integrity testing. This new approach can achieve comparable results to foundation exhumation or intrusive investigation and at a fraction of the cost. This paper presents the findings of several such studies, highlighting the benefits and opportunities for future improvement of the method.

Oct 1, 2022

By Marco Fellin, Van E. Komurka

Significant cost and construction benefits were obtained from performing a bi-directional static load test prior to construction on the Russell Street Bridge Replacement project in Missoula, Montana. The project utilized 24 drilled shafts to support two three-span bridges across the Clark Fork River. A bi-directional static load test (“BDSLT”) was performed on a large-diameter production shaft to demonstrate construction methods and confirm design assumptions. Subsurface conditions consisted of gravel with sand to a depth of 20 feet (6.1 m), underlain by gravel with sand, silt, cobbles, and occasional boulders. The test shaft had a nominal diameter of 5.9 feet (1.8 m), and an embedded length of 75.5 feet (23.0 m). The geotechnical engineer of record and the BDSLT test engineer collaborated to optimize the BDSLT jack assembly location within the test shaft, determine appropriate instrumentation locations, and plan the test protocol. The maximum applied test load was 10,707 kips (47.6 kN). Significant benefits were obtained from performing the BDSLT test, including 1) reducing each production shaft’s length by using a higher LRFD resistance factor allowed by having performed the testing, 2) using test-determined unit shaft resistances to evaluate and accept two production shafts that may have otherwise required remediation, and 3) providing the Montana Department of Transportation (and other designers) with increased presumptive unit resistance values in the gravel/cobble/boulder deposits. PROJECT DESCRIPTION The project was constructed in Missoula, Montana for the Montana Department of Transportation (“MDT”). The original bridge was approximately 60 years old, and consisted of a two-lane, 420-foot-long (128-m), four-span, riveted steel plate girder design spanning the Clark Fork River. The bridge was due for replacement owing to its deteriorated state, and the need for increased traffic volume capability afforded by a four-lane structure. HDR was the structural engineer. The preferred bridge alternate was a 459-foot- long (140-m), three-span, welded steel plate girder design. The new bridge was designed to meet current standards in accordance with MDT bridge design and AASHTO LRFD criteria. The new bridge was constructed in phases to keep traffic open during construction.

Jan 1, 2019

By Ezra Ballinger, Matthew R. Glisson

Located in downtown Fargo, North Dakota, the Block 9 Redevelopment project site contains highly- compressible soils in the upper 100 feet with groundwater about 10 to 15 feet below the existing ground surface. The owner prohibited using driven piles to avoid disturbing neighbors of the project and historically, drilled shafts are used in Fargo as a reduced noise and vibration alternative to driven piles. However, developments over the last 20 to 30 years in drilling equipment, load testing and integrity testing resulted in the project team identifying augered cast-in-place piles as a suitable alternative for this project. To reduce the risks associated with using a relatively unproven foundation system in the area, the project team used the design-build delivery method for foundation design and construction. The team also specified compression load testing and higher-than-normal integrity testing. A successful bi-directional load test validated the design parameters for the augered cast-in-place pile while thermal integrity profiling gave the team confidence that these piles would perform similarly to the test pile. PROJECT DESCRIPTION The Block 9 Redevelopment project goal was to turn an existing, at-grade parking lot in downtown Fargo, North Dakota into a public outdoor plaza, a mixed-use building and a parking ramp. The project provides new offices, retail spaces, a hotel, a restaurant and private apartments. Situated in the southeast quadrant at the intersection of Broadway and 3rd Avenue North, the project site wraps around a bank building that was to remain. According to aerial photographs, the eastern portion of the site contained a public parking ramp that was constructed between 1952 and 1976, and subsequently demolished between 2009 and 2010. The western portion of the site had some combination of buildings and surface parking visible in aerial photographs taken between 1952 and 1979. Since 1984, aerial photographs show the western portion of the site being entirely surface parking. The redevelopment included the construction of three structures: the Tower, the Podium and the Parking Ramp, as shown in Fig. 1. With plan dimensions of roughly 100 feet by 100 feet, the Tower has 1 level of below-grade parking and 19 above-grade levels rising to a height of about 230 feet above grade. The Tower contains eight levels of commercial office space, four levels of hotel, six levels of residences and a mechanical level. This configuration resulted in column service loads ranging between 435 and 2,685 kips. The Tower core area has a total service load of about 30,000 kips.

Jan 1, 2019

By Sumit Kumar Biswas, Moyukh De, Sibapriya Mukherjee

"The piles often are also subjected to lateral (horizontal) forces and moments. In fact, there are some structures where the primary function of piles is to transfer lateral loads to the ground. Proper analysis of laterally loaded piles is very important to the geotechnical and civil engineering profession.In the present investigation an experimental study has been carried out with free head short model cast iron hollow piles of outer diameter of 24 mm and L/d ratios of 8, 10, and 15. The experimental results have been supplemented by numerical techniques using PLAXIS-3D Foundation version 2.1 software. The results have been found to agree reasonably well with the experimental results. Further finite difference approach has been adoptedto reduce the computational time and to calculate the coefficient of modulus of subgrade reaction (?h) from the load- deflection data obtained from PLAXIS output at different pile depths. The parametric study has been extended for the non-dimensional form defined as flexibility ratio (F.R.),where ?h, L, Ep and Ip are the coefficient of modulus of sub-grade reaction, the embeddedlength of model pile, elastic modulus of pile material and the moment of inertia of model pile about the central axis respectively).The variation of coefficient of horizontal modulus of sub-grade reaction (?h) has been studied with respect to the following parameters for homogeneous soil system: relative density andL/d ratio. It has been found that the logarithm of flexibility ratio increases with increase inrelative density and increase inL/d Ratio. The values of ?h obtained by the proposed method have been, found to be close to the numerical results.As output of this research, graphs have been generated in respect of different parametric variations to gain an insight into behavior of piles under lateral load for short piles."

Jan 1, 2015

By Leena Korkiala-Tanttu, Noora Lindroos, Juha Forsman

"Construction works at the Helsinki city sea shoreline requires dredging and handling of contaminated sediments. Most of these soft dredged sediments are regarded as too poor quality material for earth construction purposes. Mass stabilization technology has been applied to improve the technical and environmental properties of the dredged sediment in order to utilize the material in construction. The treatment site presented in this article is placed in the West Harbor where the dredged sediments are disposed in basins, mixed with binders by mass stabilization and transported to utilization sites. The volume of these basins is about 90 000 m3. So far these basins have been used three times during the years 2011-2014. The most applied binder has been cement. Its high price and carbon footprint have encouraged use alternative binders. Other used binder materials include fly ash and end product of desulphurization from coal combustion, and fly ash from combustion of Estonian oil shale. The technical and environmental properties of stabilized sediments have been studies in the laboratory and in situ thoroughly. Some properties of the stabilized sediments which have been studied are: compression strength, modulus, hydraulic conductivity, leaching of contaminants, etc. The leaching test results show that heavy metal leaching is very low with all binder materials tested.1. INTRODUCTIONContaminated marine sedimentsMarine sediments in the coastal areas are often contaminated as a consequence of industrial and port activities, as well as the influence of cities located there. Construction activities and reclamation of shore line require dredging and handling of contaminated sediments since the level of contamination inhibit dumping of dredged sediments into the sea. Based on their technical properties, most of these dredged soft and watery sediments (clay, gyttja, etc.) are regarded as too poor quality material for earth construction purposes. Economic, sustainable and environmentally safe management of contaminated, dredged sediments is a key issue in many construction sites.In the City of Helsinki, mass stabilization technology has been applied to improve the technical properties of the dredged sediments in order to utilize the material in construction. Owing to stabilization / deep mixing / solidification, also the contamination is encapsulated in a monolithic solid of a high structural integrity. Thus, contaminants migration is restricted by the decreased surface area exposed to leaching.The treatment site presented in this article is placed in the West Harbor (a place of Helsinki called Jätkäsaari) where dredged sediments are disposed into stabilization basins, mixed with binders by mass stabilization and then transported to final utilization sites. The location and principle of these basins is presented in Figures 1-4. The overall volume of these four stabilization basins is about 90 000 m3."

Jan 1, 2015

By João Veludo, Eduardo Júlio, Helen D. Robinson, Jesús E. Gómez

"Utilization of micropiles for structural retrofit requires connection of the micropiles to the footings of the existing structure. Almost ten years ago, an experimental research effort was carried out in the US to investigate the magnitude and mechanism of development of the bond strength between micropiles and existing concrete. The study resulted in important conclusions on the mechanism of connection capacity development and provided specific recommendations for practical design of micropile-to-footing connections. In the last five years, the original study was complemented by an intensive experimental effort in Portugal aimed at answering many of the questions still remaining on this topic. This paper is a summary of the knowledge that is presently available on the capacity of micropile-to-existing footing connections. It presents the results and observations of model tests performed in the US and Portugal, as well as some tests from actual construction sites. The paper presents clear evidence that friction may be the most important component of connection capacity. It also presents a clear correlation between confinement and connection capacity.IntroductionUtilization of micropiles for structural retrofit requires connection of the micropiles to the footings of the existing structure. This is often accomplished by drilling through the footing and developing the connection by direct bond between the micropile grout and the existing concrete. Almost ten years ago, an experimental research effort was carried out in the US to investigate the magnitude and mechanism of development of the bond strength between micropiles and existing concrete. Smooth and textured micropile inserts of varying lengths were tested to failure inside pre-drilled holes of varying diameters. That investigation led to several publications (Gomez et al. 2005, Wilder et al. 2005, Cadden 2009) on the mechanism of development of bond strength between micropiles and concrete, which included a chart for preliminary bond value selection depending on the diameter of the hole and texture of the micropile.An intensive testing program was carried out in Portugal in the last five years. The program focused on answering questions posed by the original investigation and on finding the relationship between connection capacity and level of confinement. Both investigations, and especially the testing performed in Portugal, provided an invaluable amount of information on the mechanisms of failure of micropile-to-footing connections. This information should be the basis for development of design procedures that, until now, were not available."

Jan 1, 2015

By Dharmil S. Patel, Zoyav S. Benyaminov, Cassandra A. Wetzel

Rehabilitation of the Henry Hudson Bridge is nearing completion, connecting Spuyten Duyvil in the Bronx to Inwood Hill in Manhattan, New York. Constructed in 1936, the Henry Hudson Bridge spans 840 feet over the Hudson River. Challenging geotechnical aspects of this Project required a team of innovators to overcome. Rehabilitation of the existing bridge involved the replacement of sixteen bent pedestal substructures, two abutment pilasters and installation of new deep foundations at the skewbacks. However, the Bridge, roadways, adjacent Metro-North Railroad (MNR) structures and New York City (NYC) Parks land were to remain open to the public for use, with minimal disturbance. In addition to physical constraints, geologic site conditions varied widely across both sides of the River, with varying bedrock quality and depth, greatly impacting the proposed design and construction. Extensive analysis of bedrock conditions was conducted to locate areas of potential wedge failure. The implementation of anchors was used to reinforce rock stability where pedestals and pilasters were replaced. This paper describes several challenging technical and natural aspects overcome in the rehabilitation of the Henry Hudson bridge foundations, including varying geologic site conditions, access restrictions, construction limitations, project specifications and design requirements.

Sep 8, 2021

By Y. M. Ha, T. D. Nguyen, D. T. Nguyen, H. K. Choi

Conventionally, cement deep mixing (CDM) columns are designed to have constant diameters over the improved depth as this facilitates the construction procedures. However, this design pattern may be inefficient in cases of spread footings or shallow foundations. This paper first briefly introduces principles of an improved CDM method that can create head-enlarged CDM (termed PF) columns. A simple analysis approach was introduced to obtain optimal shape of PF columns that results in minimum settlement. The effectiveness of this improved method over the conventional CDM method was then illustrated by settlement analysis for an actual footing in a case study using two recommended analytical methods in the literature. Analysis results from the case indicated that by using the same amount of soil-cement mixed volumes, settlement from a footing on PF columns can reduce up to 10 % compared with that from the same footing on CDM columns. In addition, a material quantity comparison for the case indicated that to have the same settlement values the volume of each PF column can be reduced of around 10% compared with that of the CDM column. INTRODUCTION The cement deep mixing (CDM) method is one of the most popular methods in ground improvement works. Details on the method such as construction procedures, necessary equipment and recommendations are described in many references or manuals (e.g. Bruce et al. 2013, BS EN 2015, Kitazume and Terashi 2013). Conventionally, CDM columns are designed to have constant diameters over the improved depth as this facilitates the construction procedures. However, this design pattern is found inefficient in cases of spread footings or shallow foundations as the upper soil layers are naturally weaker than the deeper ones but are subjected to larger amount of induced stress from the superstructures.

Jan 1, 2019

By David Corke

The paper presents the development of Federation of Piling Specialists (FPS) calculation of rig track loading, the production of the Building Research Establishment document “Working platforms for tracked plant” (BR 470), working platform testing and considerations of rig stability. The paper also discusses the importance of rigorous and well documented procedures and proposed future development of rapid working platform testing methods. Topics presented include the fundamental requirements and principles involved in the testing, design and maintenance of working platforms, rig track loading, the BRE design method and site testing analysis. The paper stresses the need for testing and design processes to be robust and simple and quick to perform as there is often little time between the award of a contract and the need to start work on site. Also, it is vital that all aspects of working platform design can be carried out with information that is available to the platform designer. Developments in the UK over the last two decades have resulted in improved quality and safety of working platforms that will hopefully be further enhanced as design and testing methods continue to improve.

May 1, 2022

By George Aristorenas, Carlos Englert, Jesús Gómez

"Laboratory test data of strain softening soils exhibit the development of a maximum (peak) shear strength followed by a decrease in the strength with continued straining. The rate of strength loss decreases such that an asymptotic minimum value, known as the residual strength, is approached. This paper presents an investigation of the evolution of strength degradation in excavation supported soils that exhibit strain softening behavior. The paper presents a numerical investigation of excavation support of slicken-sided clay, and results of shear testing on materials with similar strain softening behavior. A strain softening constitutive law is presented that can be used with the finite element computer software Plaxis for analysis of excavation support. A typical design section of a deep excavation support in stiff, fissured clay is presented that illustrates the limitations and conservatism of the residual strength approach for excavation support design. Finally, a discussion is presented on the impact of stiffer walls such as diaphragm walls, compared to less stiff systems such as sheet piles, on the design parameters.INTRODUCTIONIn the Washington, D.C. metropolitan area, the Potomac Formation is generally composed of stiff, fissured clays. Geotechnical engineers often associate the presence of slicken-sided planes within the formation as evidence that the soil cannot develop its peak strength. Although it is unclear how old and continuous these slicken-sided planes are, their occurrence, persistence and orientation appear to be somewhat random. Due to this uncertainty, the design of open cut slopes in these materials is often conservatively performed assuming residual shear strength values. This design approach may be justified for long-term open cuts when there is limited amount of geotechnical information and in view of back stability analyses of past slope failures. Furthermore, the lack of confinement in open cuts allows relatively high shear strains near the surface and toe throughout their existence, which promote mobilization of post-peak strength values and the ensuing progressive failure. Indeed, such behavior has been discussed in the past (Skempton, 1970; Schnabel et. al., 1982; Derrenbacher, 1998). A thorough study by Mesri et. al. (2003) of numerous slope failures concludes that the lower bound strength for stability analysis of non-failed slopes is the fully softened strength, which is intermediate between the peak and residual strengths, but that part of the slip surface may be in a residual condition prior to failure."

Jan 1, 2015

By Ambarish Ghosh, Rituparna Dey, Indrajit Chowdhury

"In port and harbor facilities, jetties and cargo berth terminals are usually installed on piles that remain partially embedded in soil, while a part of it behaves as columns supporting top deck. Technology in vogue adapts a pseudo static analysis in computer where the top deck including piles are analyzed as an integrated system based on finite element method when the piles are modeled as beam elements, while the soil in which it is embedded is modeled as linear or nonlinear springs. Typical berthing force of the ship is considered as a pseudo static force where the dynamic characteristics of the force is taken into consideration by an equivalent impact factor and little study exists on the actual behavior of these type of piles under the transient shock due to berthing impact. Present paper proposes an analytical solution based on which one can compute the dynamic response of such jetty piles considering shear modulus of soil constant with depth. Considering the solution is analytical in nature no special software is needed and can well be adapted fordesign office practice using generic utility software like MATHCAD, MATLAB etc. that makes theproposed model computationally very efficient.INTRODUCTIONResponse of piles under dynamic load has been an important study in the realms of civil engineering, where significant research has been carried out on its dynamic behavior under harmonic loads like one experienced in a machine foundation or under seismic force.A number of researchers have given solution to this problem like Parmelee et al (1964), Tajimi (1966), Penzien (1970), Novak et al (1974, 1983), Banerjee and Sen (1987), Dobry and Gazetas (1988),Chowdhury and Dasgupta (2008).However, most of these theories are based on piles loaded under harmonic load and valid for long piles where structural failure precedes the soil failure considering the piles are long and flexible."

Jan 1, 2015

By Ahmad Mahboubi

The damage caused by catastrophic earthquakes has always been an incentive towards more sophisticated building codes and requirements. In parallel to computer technology development, the engineers? attitude towards acquisition of more accurate results is increasing. This approach leads to designation of structural elements with more elaboration considering different aspects of their behavior. In addition, less simplified methods will be considered as satisfactory for analyzing such problems. The problem of soil-pile-structure interaction is one of the phenomena that can be included in this category. In general, there are two methods by which the study of soil-pile interaction phenomenon is studied. These include direct and sub-structuring methods. The sub-structuring approach relies on the linear or slightly non-linear behavior of soil since it employs the results of kinematic interaction analyses for inertial interaction studies. In the past, the kinematic interaction between pile-soil was considered as negligible. This was due to the softer nature of the surrounding soil that increased the time period of vibrations. However, more research revealed that although this approach was consistent in many cases, there were some sites where the time period decreased. This was due to the material properties of the foundation and the soil, in a way that caused the frequency of vibration meet natural frequency of the system. The second type of interaction is the inertial interaction which reflects the effect a structure on top exerts on the oscillation experienced by the foundation. This paper examines the impact of vertical load on the inertial interaction by virtue of impedance functions. Three different load cases for the structure at the top of a pile foundation were considered for the analyses conducted in this study. The changes in the stiffness and damping of the system by frequency are studied and finally, the results are presented.

Jan 1, 2010

By Nick Hytiris, Mohammed Al Maadheedi, Slobodan B. Mickovski

This paper explores the capacity effects of a square steel plate welded at the ground surface on a driven open-ended steel pile (i.e. the plate would touch the ground surface after the pile achieves the required penetration). A series of strain-controlled, 1-g laboratory tests were undertaken on piles with and without a square steel plate attached. The piles were driven in dry, loosely packed, uniform sand. Two plates were used, one with a breadth equal to two times the diameter of the pile (2D) and the other with a breadth equal to three times the diameter of the piles (3D). A 20% increase in capacity was recorded for the 2D plate, and a 110% increase in capacity was recorded for the 3D plate when compared to the pile without an attached steel plate. The back-analysis of the results allowed the derivation of a new expression to calculate the capacity of bearing plates, which accounted for the effects of sands compaction and dilation. By extrapolating the findings of these tests to a hypothetical scenario, a model design problem was described where the length of a pile can be reduced by 20% to 60% (depending on the load) by using a plate attached to the pile. The results of this study can help designers to minimise penetration depth; thus, achieving a more economical and sustainable design.

By Mohammed Al Maadheedi

This paper explores the capacity effects of a square steel plate welded at the ground surface on a driven open-ended steel pile (i.e. the plate would touch the ground surface after the pile achieves the required penetration). A series of strain-controlled, 1-g laboratory tests were undertaken on piles with and without a square steel plate attached. The piles were driven in dry, loosely packed, uniform sand. Two plates were used, one with a breadth equal to two times the diameter of the pile (2D) and the other with a breadth equal to three times the diameter of the piles (3D). A 20% increase in capacity was recorded for the 2D plate, and a 110% increase in capacity was recorded for the 3D plate when compared to the pile without an attached steel plate. The back-analysis of the results allowed the derivation of a new expression to calculate the capacity of bearing plates, which accounted for the effects of sands compaction and dilation. By extrapolating the findings of these tests to a hypothetical scenario, a model design problem was described where the length of a pile can be reduced by 20% to 60% (depending on the load) by using a plate attached to the pile. The results of this study can help designers to minimise penetration depth; thus, achieving a more economical and sustainable design.

By Hidekatsu Takeuchi, Masaru Sakakibara, Shigeo Tanabe, Kenji Harada, Akihiko Suzuki, Shoji Morihana

"Deep mixing (DM) method, one of the most commonly used solidification methods, is based on the principle of solidifying soft ground. It can be classified into two categories such as Cement Deep Mixing (CDM) method and Dry Jet Mixing (DJM) method which apply hardening agent in slurry condition and in powdery condition respectively. In recent years, DM methods have undergone changes that have evolved them from the traditional method to meet the needs of the diversifying market. Among them, the Contrivance-Innovation Clay Mixing Consolidation (CI-CMC) method is a DM method which mixes a cement-type hardening agent in slurry condition mechanically with soils in situ and incorporates the innovative technique, “atomized ejection” that has been developed to allow faster installation of larger diameter columns without sacrificing quality compared with conventional methods. At this technique, the atomized hardening agent is discharged together with compressed air through a device incorporated into the mixing blade. It also has advantages of performing the works with low-displacement of the surrounding soils in consideration of environmental friendliness and with higher penetration capability against hard ground.This paper presents the technological outline of the above-mentioned CI-CMC method, focusing on the atomized-ejection technique, followed by some construction examples, applied to the self-earth-retaining wall, to the hard ground and the area adjacent to the existing structures.INTRODUCTIONAccording to the accumulation of its case histories, Deep Mixing method has been receiving the demands of its application to more challenging conditions, such as harder ground condition, and requirement of lower displacement of the surrounding ground during its operation. In addition, to match its price against the other cheaper methods and widely receive its benefit of higher quality, the cost reduction of Deep Mixing is also one of the major challenges. For the cost reduction, higher productivity and lower consumption of the material to obtain the equivalent strength and homogeneity with the conventional method are required.The Contrivance-Innovation Clay Mixing Consolidation (CI-CMC) method has been developed to meet these demands. CI-CMC incorporates the mist ejection that has been developed to achieve faster installation of larger diameter columns without sacrificing quality compared with the existing methods. Normally, we obtain cement columns of about 1.0 m in diameter by using Deep Mixing method. To increase the productivity, it is not preferable to drastically increase the penetration and withdrawal speed of the mixing blades because of the hardness of the ground and restriction by minimum number of passage of rotating blades per a certain height of the soil cement. Instead, the expansion of diameter of the columns will simply increase the productivity. The development of the new mist ejection system, as shown in Photo 1, has enabled the diameter of soil cement columns to 2.0 m on single axis while 1.6 m on double axes. Mist ejection means that the hardening agent slurry is sprayed into the ground in mist form together with compressed air thereby achieving homogeneous mixing and reducing the resistance on rotating blades."

Jan 1, 2015

By Dipl. -Ing. (FH) Thomas Schmitt, Dr. Melvin England

Foundations in Geneva are difficult and expensive due a large overlayer of clay and silt above competent bearing material in the moraine. Common foundation schemes use deep barrettes or bored piles, first passing large, weak layers of soil before finally reaching acceptable, solid moraine with reasonable values of skin friction and end bearing resistance, thus requiring further deep penetration for the necessary length for load transfer in the moraine. Depths of more than 60 m (200 ft) in Geneva are common in this region. At the Onyx-Project Geneva Implenia Foundation Company also encountered these circumstances. Despite usual solutions Implenia referred to an old and well known, but still intelligent and in today’s words smart, efficient and economical solution. Using small shafts, passing the large layers of clay and silt, ending with the pile toe in the underlaying moraine with a belled or underreamed base was the technic adopted to save drilling time, reduce spoil and concrete, so finally reducing the CO2 footprint. Piles with enlarged base (“belled” or “underreamed”) are reported at the beginning of the 20th century, for example at Chicago, which has a quite similar geotechnical structure as Geneva with the need of deep foundations. The first pile base enlargements were built in hand-dug caissons with wood lagging and steel ring bracing. In the 50s and 60s piling works were more and more mechanized, driven by the development of more powerful cranes and specialized drill rigs. Additionally the first tools for mechanized base enlargement were invented around that period. This report describes the project situation at Geneva, the drilling and enlargement technique of the pile base, the verification of the design values with an in-situ bi-directional load test and the smart execution by reduction of CO2 and costs.

May 1, 2022

By Ruth McKeown, Gilson de F. N. Gitirana, Murray Fredlund, HaiHua Lu

The current design standards for the use of anchors in slopes is based on two-dimensional (2D) limit equilibrium analyses. Anchors are considered as discrete loads and the 2D anchor, factored based on the spacing distance, corresponds to extending anchors indefinitely in the third dimension. A three-dimensional (3D) analysis offers a more realistic representation of the problem, including the true discrete nature of the anchor point loads. This paper explores the typical differences between analyzing anchors in 2D and 3D, using four typical conceptual models. Slopes with constant cross sections were shown to be adequately represented by the traditional 2D approach. The maximum difference between 2D and 3D models was 21% and becomes negligible for lower anchor spacing values, as expected. A slope with an external load was analyzed to evaluate critical slip surfaces with lower aspect ratios. Slip surfaces with lower aspect ratios presented higher edge effects that contributed to the stability of the slope. The results indicate that optimum design requires the 3D evaluation of field conditions inducing low aspect ratios, such as concave and convex surfaces, weak layers, and external loads. INTRODUCTION Slopes may be stabilized using a variety of solutions, including anchors. When performing an analysis, geotechnical engineers often follow the traditional two-dimensional (2D), Limit Equilibrium Method (LEM). It is important to understand the consequences and limitations of the assumptions on which the 2D LEM is based. There are numerous studies on anchors that show the importance of considering the actual three-dimensional field conditions. Desai et al. (1986) proposed a three-dimensional procedure based on the Finite Element Method and considering elastoplastic behavior and interface elements, to account for stress and displacement distributions, the relative motion between the anchors and the soil mass, and nonlinear soil behavior. Several important stabilization mechanisms were explained. The role of grout injection was evaluated in terms of the produced normal stresses along the anchor-soil bounding surface. The approach was shown to reproduce adequately experimental tests on a sand, proving realistic stress distributions around the anchor. Nonlinear soil behavior influenced to a large extend relative interface motions. Michalowski (1989) applied an upper-bound limit analysis in 3D to slope stability analyses. Anchors were not specifically considered in this study, but the consideration of locally loaded conditions shed light on important modeling aspects. The manner how the slide mechanism becomes three- dimensional as the slope is locally loaded was demonstrated. This emphasizes the fact that anchors should produce field conditions that require 3D analysis approaches.

Jan 1, 2019

By Dzianis Proshchanka, Yoshi Izumi, Koji Mitani, Ayuna Kitaura

"A new pile driving and drilling navigation system has been developed. It utilizes the commonly used surveying total station, combined with an innovative reticle. Conventional crosshairs have been replaced by a concentrically circular reticle called Baum. It allows for easily performed measurements of central axes of cylindrical objects such as piles, chimneys, electricity poles, etc. This provides several significant advantages compared to other existing systems. It is cost-effective as only one operator is required to control deviations in positioning and inclination. Furthermore, repetitive reinstallation of the instrument is not required for every pile driven or hole drilled. It is also a safer method, as workers have no need to be near a pile driver or drilling machine to perform the measurements. With Baum Station, necessary measurements can be performed away from the actual work area. Moreover, it is highly accurate with real-time solutions, as three-dimensional orientation information for the pile/drill is obtained simultaneously with the pile being driven or the hole being drilled. This allows for the highest levels of precision-control and correction to minimize eccentricity of the intended center positioning.INTRODUCTIONBackgroundIn foundation construction for structures, pile foundations are widely used for deep bearing strata. There are two patterns to driving piles: vertically or obliquely to the ground. The shapes of the piles are normally cylindrical. Vertical pile foundations are employed as the foundations of many structures due to their high workability. There is a problem however, which is that this method does not bear measurement data as construction accuracy is visually checked. On the other hand, tilted pile foundations are rarely employed because it is too difficult to ensure construction accuracy. In addition, commonly used percussion methods create noise and vibrations when the piles are hit, while there are advantages that thinner piles are available, ensuring earthquake-resistance, as tilted piles curb horizontal displacements of structures, which may be caused by earthquake ground motion. However, current requirements of cost reduction bring professional attention to tilted pile foundations, which can be driven reasonably and economically with much research of tilted piles having been carried out to improve their capacity. Also, a method of screwing piling has been developed, which produces small amounts of noise and vibrations. This method has solved tasks of workability and environmental burdens, and is becoming more and more common. However, there is a necessity to develop a method to accurately measure angles of piles’ axes in order to drive piles into the ground with appropriate angles. It is also expected to find out a way to control construction information, such as correction amount and driving record."

Jan 1, 2017

By Dale Berner, Michael O’Sullivan

"This paper focuses on lessons learned from the innovative designs, in-the-wet construction methodology and modified foundation conditions, for two United States Army Corps of Engineers, USACE, Megaprojects:(a) The over $2 Billion Olmsted Dam across the Ohio River for the Louisville District; and(b) The $1.75 Billion Inner Harbor Navigation Canal, IHNC, Lake Borgne Hurricane Barrier in New Orleans for the Hurricane Protection Office, and the New Orleans District.Design innovations for the 24-inch dia. pipe pile foundation for the Olmsted Dam project include: (i) the use of controlled-fixity moment connections to the dam monoliths in order to tune the response of the dam under the 8.3 Richter scale seismic Maximum Credible Event, MCE; (ii) soil densification to inhibit liquefaction potential and (iii) design to facilitate underwater construction in a river with a highly moveable sand bed.Design innovations for 66-inch dia. concrete cylinder piles for the IHNC floodwall include: (i) the use of soil structure interaction, SSI, analyses to verify capacity to resist deep-seated failure plane in soft soil, while limiting lateral deflections to acceptable limits; (ii) the use of geo-fabric and scour stone for enhanced foundation response and (iii) design for ""in-the-wet"" construction on a fast-track basis.LESSONS LEARNED FROM THE INNOVATIVE OLMSTED DAM FOUNDATIONThe over $2Billion Olmsted Dam on the Ohio River is currently under construction 16 miles upstream from the confluence with the Mississippi River. It will consist of an 800-foot-long tainter gate section, a 1,400-foot navigable pass, two boat abutment sections, a fixed weir section, and upstream and downstream scour protection. The Olmsted Dam and its two, 1,200-foot locks, which were built in 2002, will eventually replace both Locks and Dam #52 and #53, both built in 1929, and thereby bring significant benefits to the Ohio River navigation system.In 2002, the Jacobs/COWI JV completed the design of the dam; which was an engineering challenge for several reasons, including:(a) Its proximity to the New Madrid Fault, could impose an 8.4 Richter Scale seismic event on the structure, which is located in an area of potentially liquefiable alluvium. The extensive seismic analysis performed by COWI included a response spectra analyses; lateral pushover analyses of pile foundations; hydrodynamic added masses; pile group effects; and the development of kinematic motions as a result of the soil-pile-structure interaction.(b) Maintaining vessel traffic along the river and accommodating fluctuating river elevations between 30-40 ft annually, and as much as 60 ft in a 100-year period.(c) Designing for the scour and uplift forces of artesian ground water and preserving a wildlife sanctuary on the Southern shore at the dam site."

Jan 1, 2017

By Rajasekar Subbian, Jessica Oudhof

In the Netherlands pile foundation design is done using CPTs in accordance with EC7 national annexure. The capacity per tip level is calculated for every CPT followed by zonation to find the tip level per zone. The correlation factors are used to take into account the variability in ground across the zone and they depend upon the number CPTs within the zone. The CPTs and pile tip levels selection for zoning is an iterative process that can demand significant manual effort to produce an economical pile plan. This often leads to the use of conservative correlation factors in order to accelerate the design process. Thus, it has been automated in a tool with CPTs, pile location and loads, and capacities as input. The tool has also been employed in two case studies and the results are compared to the current design practise.

May 1, 2022