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By Franz-Werner Gerressen

In the changing construction environment clients are searching for new technology to complete their projects in shorter times. Manufacturers are therefore developing solutions to speed up established construction methods. The significant progress in recent years with the development of increasingly powerful drilling rigs is providing piling companies increase options for the execution of specialist foundation projects. The double rotary drilling methods are primarily used for the construction of pile walls as support for deep excavations. Typically these retaining walls are designed and installed as cased piles using the established Kelly drilling mode. However, more recently it is more popular to undertake these projects with the Cased Continuous Flight Auger (CCFA) system. This paper provides an overview of drilling with double rotary methods, in particular the monitoring during installation.

Jan 1, 2009

By Dr Karsten Galipp, Kai-Julian I. Hendler, Prof. Manuel G. Pinheiro, Dr Peter J. Bourne-Webb

With a share of approximately 11% of global greenhouse gas emissions, the construction industry contributes significantly towards climate change. This is why construction projects should not only be assessed on costs and technical solutions, but also on their carbon emissions. Life Cycle Assessment (LCA) is a tool which can quantify the environmental impacts of a construction project over its entire lifetime. The objective of this study was to determine the carbon footprint of three types of quay wall structures, namely sheet pile combi-walls, open piled decks and caissons using an LCA approach. Each of these quay walls were studied under the same boundary conditions, such as design life, ground conditions, dimensions, location and so on. The analysis showed that the sheet pile wall has the lowest carbon footprint whereas the open piled structure has the highest. Furthermore, it could be shown that the largest share of greenhouse gases (approximately 80%) is emitted during the production of construction materials. The transportation of materials and construction activities each contributed under 12% to total emissions. The sensitivity analysis showed that with innovative approaches, such as adapting the concrete mix design, the carbon footprint could be reduced by 26% to 40%.

May 1, 2022

By Justin Phillips

The redevelopment of Bow Bells House in London has thrown up a number of challenges that will increasingly be faced by developers of congested sites. In the context of pile reuse this paper examines four key issues: 1. The Developer?s perspective on sustainability, cost, programme and risk management. 2. The nature of pile testing including timing, the balance of extent of intrusive works whilst retaining the existing piles and identifying representative levels of testing. Four key elements of investigation; geometry, integrity, durability and capacity are evaluated. 3. In terms of design this paper supports the adoption of alternative probabilistic methods aligned with communicating to Clients in terms of acceptable ?probability/risk of failure? in place of a factor of safety approach. 4. The project also highlights a number of issues that will require greater attention to maximise the future reuse potential such as foundation load transfer platforms and promoting developments based on early collaborative framework design and contracting across the supply chain.

Jan 1, 2008

By K. Madhusudan Reddy

"Pile response under combined uplift and lateral load is very important and it is imperative to evaluate the effect of combined loading and only few studies were reported on pile behavior under combined uplift and lateral loads. Model pile made-up of aluminum having an outer and inner diameter of 25.4 mm and 19.4 mm respectively is used. Dimensions of the model steel tank are fixed as 1.0 m x1.0 m x 1.2 m (depth) to avoid the boundary effects under combined lateral and uplift loads. Experiments were carried out on single piles at isolated uplift, isolated lateral loading and combined lateral and uplift loading, embedded in sandy soil. Results indicate that load–deflection behavior is nonlinear for isolated uplift and lateral load tests as well as in case of combined loadings. It is also observed that the behavior of piles under isolated loadings is substantially different when compared to combined loading.INTRODUCTIONPile foundations are generally used to support compressive loads from superstructures. Some structures, like transmission towers, mooring systems for ocean surface or submerged platforms, tall chimneys, jetty structures, etc. are constructed on pile foundations, which have to resist large lateral and uplift loads and moments. The various loads (compressive, lateral and uplift) and moments act on the piles simultaneously rather than isolated manner. There are well-established theoretical methods present to evaluate the pile behaviour under different isolated loadings namely, verticalcompressive, vertical-uplift and lateral (Poulos and Davis, 1980), but there are very limited studies focused on pile behaviour under combined loadings. Though there is good number of studies reported on pile behaviour under combined compressive-lateral and compressive-uplift loadings (Ramasamy, 1974; Jain et al. 1987; Zhang and Small, 1999; Dash and Pise, 2003; Karthigeyan et al. 2006 & 2007; , there are only very few studies reported on pile behaviour under combined uplift and lateral loads. Darr et al. (1990) described an approach to a rational solution of the interaction of pile to combined uplift and lateral loads based on analytical and experimental studies. Influence of cyclic loading was also considered. Narasimha Rao and Prasad (1993) investigated the uplift behaviour of pile anchors subjected to lateral cyclic loading. There were many onshore and offshore situations where lateral cyclic loading may affect both the pullout and lateral loading capacity of pile anchors. Jetty and wharf structures are usually subjected to lateral forces from wave and wind action. If these cyclic lateral loads are acting on the supporting piles, the resulting movement of the upper part of the embedded length of pile may reduce the skin friction. This progressive deterioration in pullout resistance may not be reflected by a pullout test made soon after the installation. Hence, Tomlinson and Woodward (2008) pointed out that a generous safety factor on the ultimate pullout load should be adopted for piles in such situations. Mroueh and Shahrour (2007, 2008) presented a threedimensional finite element analysis of the response of battered piles to the combined lateral and vertical pullout loads. Nevertheless, the model is not validated well due to lack of good experimental data based on rigorous experiments. Thus there is a scope for investigating the effect of lateral load on pile behaviour under uplift load and vice versa based on carefully designed experiments, which is main focus of the present investigation."

Jan 1, 2017

By Filippo Maria Leoni, Wesley Schmutzler, Matteo Bertoni

"Deep Mixing Method (DMM) for the Rio Puerto Nuevo Project (Project) in San Juan was chosen by the Corps of Engineers to improve the soils adjacent to a 92 inch ID forced sewer main relocation and to improve the soils for the base of a new drainage channel. The soils to be improved consisted of sandy fill, soft clays, organics and stiff, plastic clays. A pre-construction soil investigation campaign, followed by a Bench Scale Mixing Programme and a Full Scale Field Test were performed during the pre-construction stage to assess soil properties, select binder type and dosage, and disclose the most suitable combination of injection parameters to improve the different soil layers. Production started at the end of August 2012 and was completed in October 2013; over 3,000 DMM elements were installed to a maximum depth of 57 ft below ground for a total gross volume of approximately 125,000 cubic yard. Each element consisted of two 5.5 ft diameter overlapping columns installed simultaneously, and their layout was such to meet the 100% Area Replacement Ratio required by the design. The ground improvement was successfully completed despite some difficulties due to a considerable amount of obstructions. Wet grab sampling and UCS testing of the retrieved specimens were designed as the main QC/QA method for the verification of the quality of the ground improvement. Upon completion of production, approximately 3,000 specimens were cast. The contract also required continuous coring of at least 12 randomly selected DMM elements and the testing of 8 cored specimens per bore for strength assessment. This paper will illustrate means and methods used in the field to construct the designed ground improvement and the results of the QC/QA program, with a focus on the differences between wet grab and coring sampling methods.INTRODUCTIONThe Rio Puerto Nuevo project involved the stabilization of a major drainage channel using the Deep Mixing Method (DMM), and the relocation of a 92 inch ID forced main sanitary sewer outfall. Previously, in 2004, a 40 x 16 x 2,000 ft. box culvert was installed under a different contract to convey runoff waters to the ocean.However, the connection between this culvert and the upstream network of channels was not constructed due to the presence of the forced main sewer pipe. In order for the drainage system to be completed and function properly, the 92 inch ID forced main needed to be lowered about 20 ft to allow for proper drainage.DMM was chosen by the US Army Corps of Engineers to stabilize the drainage channel as well as improve the soil under the relocated sewer main. The DMM was arranged in different zones (A through E) with variable top and bottom design elevations as can be seen in the typical cross section for Zone A (deeper and with a higher strength requirement) and Zone B as an example (Figure 1)."

Jan 1, 2015

By Aniruddha Sengupta, Rana Chattaraj, G. R. Reddy, Raj Banerjee

"Earthquake induced liquefaction in saturated granular soils is an important phenomenon which causes severe damage to life and property. In the present study, dynamically induced liquefaction of saturated Kasai River sand is studied in 1-g shake table to assess its liquefaction potential. In the shake table, the soil was subjected to sinusoidal motions of amplitude 0.35g at a frequency of 2Hz. A numerical model using FLAC 2D (Itasca 2005) was performed to simulate the shaking table tests. Reasonably good agreement between the experimental and the numerical results has been observed. Moreover, wavelet analysis has been conducted to identify the occurrence of liquefaction in sand and to correlate the observations found from the experiments. The nonlinear curves used to represent shear strain dependency of stiffness of the Kasai River sand was obtained from cyclic tri axial tests.INTRODUCTIONThe term Liquefaction is used in conjunction with a variety of phenomena that involve soil deformations due to cyclic disturbance in saturated soil under undrained conditions. The generation of excess pore water pressure is the hallmark of all liquefaction related phenomena and the reduction in the volume or the tendency of cohesionless soil to densify during undrained loading condition as prevails during an earthquake is also well known. Use of shaking table tests to understand liquefaction of soils has been demonstrated by several researchers (Ye et al. 2013; Ha et al. 2011). Mohajeri and Towhata 2003 and Towhata et al. 2006 carried out 1-g shaking table tests on soil models prepared in laminar box to study the rate dependent behavior of liquefied soils. Ueng et al. 2010 used a biaxial laminar shear box mounted on shaking table to study the settlements in saturated clean deposits of sand and related the volumetric strain in liquefied sand to the relative density for various shaking durations and earthquake magnitudes. Maheshwari et al. 2012 reported increase in liquefaction resistance of reinforced sand through shaking table tests and concluded that the type and amount of reinforcement in the soil layer has influence on its liquefaction potential.The objective of the present study is to compare the behavior of dry and saturated Kasai River sand when subjected to seismic shaking. The Kasai River separates two growing cities, Medinipur and Kharagpur in the state of West Bengal in India. A number of road and railway bridges exist over the river connecting the two cities. The area being in Seismic Zone III, that is, a zone with moderate probability of earthquake, it is important to characterize the behavior of the Kasai River sand during a possible earthquake event especially when a number of bridges are existing over it. Small scale laboratory model tests and numerical analyses using a commercial finite difference algorithm called FLAC2D (Itasca 2005) have been utilized to study the difference in behavior of dry and liquefied Kasai River sand during dynamic loading conditions."

Jan 1, 2015

By John P. Turner, Benjamin J. Turner

"This report describes a research project for evaluating the applicability of the widely accepted 80 percent criterion for elongation of ground anchors to anchors with unbonded lengths exceeding 100 feet. This issue is driven by several recent projects involving ground anchors for landslide stabilization in which a significant percentage of the anchors did not meet the criterion that requires measured elongation during proof load testing of at least 80 percent of the theoretical elastic elongation. The projects involved anchor unbonded lengths in the range of 85 to 220 feet, which is outside the range traditionally used in practice, although anchors of this length are being used more frequently for landslide stabilization. The principal objective of this research is to address whether the widely accepted criterion of 80 percent elongation is applicable for such applications, and whether other factors affect the ability of anchors to meet the criterion.Analytical methods for predicting transfer of load along the length of steel strand due to friction loss are used routinely in the prestressed concrete industry. These analytical expressions provide a rational framework for quantifying changes in load due to friction along the length of a ground anchor in terms of a ‘wobble coefficient’ (K) as defined in Aalami (2004). Values of the wobble coefficient for ground anchors can only be determined by back-calculating from load tests, i.e., fit the value of K to the appropriate analytical expression based on the known test load and measured percent elongation. The analytical basis is first developed and shown to provide a tool for evaluating results of anchor load tests to determine the magnitude of expected elongation as a function of unbonded length. Next, a database of anchor load tests is used to back-calculate values of K for anchors with unbonded lengths in the range typically used in geotechnical applications (< 100 feet). These values of K are then used to calculate expected friction loss for anchors with high unbonded lengths (100 to 250 feet) to evaluate whether the 80 percent criterion is reasonable."

Jan 1, 2017

By Abid Adekunte

Traditionally, designers and contractors provide additional external supports to retaining walls through the use of tie-back anchors or braces. Both approaches are known to have their shortcomings; braces limit working space within excavation areas, while tie-backs are seldom used in built-up areas where intrusion into adjacent property of non-cooperative owners has to be avoided or in situations where sensitive structures exist behind the wall. This paper focuses on the design, construction and monitoring of deep excavation support systems on two separate projects located in different ground conditions in the Republic of Ireland. On both projects, conventional ground anchorage and propping were inapplicable. This led to the development and application of two different novel solutions on both projects. Methods of wall performance monitoring on both sites also differ. Wall monitoring results show these innovative methods to be safe and effective. Advantages of the novel solutions over traditional approaches are highlighted.

Jan 1, 2010

By Chris L. Powell, Russell J. Denny.

"The remotely located Cockatoo Island iron ore mine off the Kimberly coast in Western Australia, which has been in operation since 1951, was recently expanded up to 50m below sea-level using staged construction of a rock-filled seawall around the open cut mining operation. The most recent stage of the seawall expansion required a seepage reducing cut-off barrier to be installed through the seawall into underlying seabed sediments. A line of grout holes at 1m centres was proposed to form the seepage barrier, with grouting extending 17m below the top of the seawall. Top hammer drilling techniques were used to penetrate the 12m deep rockfill to seabed level, and permeation grouting carried out within the rockfill to fill voids and stabilise material around grout holes. The local 10m tides meant that tidal washout of fines and grout would be a major risk, and so a combination of cementitious and chemical grout was used to create rapid gel times. Following permeation grouting, holes were re-opened to allow jet grouting to hydraulically mix and grout permeable seabed sediments below the seawall. Using the duplex jet grout system in a single pass to 17m below platform level, the jet grouting was extended upwards into the seawall fill itself to overlap with the earlier permeation grouting. Finally a soil/cement mixed capping trench was installed using slurry trenching techniques with soil/cement/bentonite mixed backfill in order to complete the grout treatment. The approach taken allowed considerable onsite flexibility in technique. An automated slurry batching plant allowed adjustment of mixes to suit the varying subsurface conditions which were encountered during the works.IntroductionLate in 2013 Wagstaff Piling was engaged to install a seepage barrier through a rockfilled seawall built to allow expansion of sub-sea iron ore mining operations on Cockatoo Island off the remote Kimberley coast in the North West of Western Australia. Earlier stages of seawall construction had used a variety of different construction techniques with varied success, and the history of sub-sea mining on the island had been plagued with failures, including failures in the slope of the seawall itself, hanging wall failure underneath and inside the seawall, and footwall failures as the ore was mined leaving the rock face inclined at 55 degrees, parallel to the bedding. The current expansion, known as the Stage 4 expansion, was more tightly constrained by the pit geometry and available materials than previous seawall expansion stages that adopted clay core and sheet pile seepage barrier solutions. In Stage 4, an innovative grout curtain seepage barrier solution was selected to ultimately provide the necessary cut-off to allow access to high grade ore, while protecting the mine from inundation by the sea."

Jan 1, 2016

By D. K. ] [Gupta

The Foundations of the Shear keys and alround cut off for Power House -IV of the Western Yamuna Canal Hydroelectric Project at Bhudkalan, Haryana were to be laid at a depth of 26M below the N.S.L and 24.4M below ground water table. The foundation of the drainage sump was to be laid at still higher depth, Viz 29.OM below N.S.L. The Sub soil at the site consisted of Gravel with some amount of sand. The laying of the foundation at such a great depth, at a large depth below the ground water table and that too under such difficult sub-soil conditions encountered a large no of Geotechnical problems-viz excessive seepage, side slope sloughing and sand boiling during excavation. Under the circumstances at the site, the modified foundation construction procedure i.e a battery of M. S. Troughs was placed in flowing water conditions and concreted thereafter, resulting in a sizable cut in dewatering and reducing a significant amount of time and cost of construction affecting a saving of crores of rupees at the state exchequer. Sheet Piling was used to prevent side sloughing in the foundation pit.

Jan 1, 1996

By Patrick J. Hannigan, Alex Ryberg, Rozbeh B. Moghaddam

Driven piles are widely used for foundation support. In the vast majority of cases, an increase in pile capacity occurs with time which is referred to as “set-up.” However, in a very limited number of cases, a decrease in capacity with time can occur. This phenomenon is referred to as “relaxation.” This paper will provide a brief review of the relaxation phenomenon, as well as pile driving information and dynamic test data on cases where relaxation has occurred. The pile types in the presented relaxation cases include H-piles, open-end and closed-end pipe piles, prestressed concrete piles, and prestressed concrete piles with H-pile stingers. The soil conditions where relaxation occurred includes dense to very dense fine sands, heavily over consolidated clays, and weak laminated rocks. Relaxation information from 36 piles at 26 sites is assessed. The collected data will assist foundation designers by identifying the subsurface conditions where relaxation has occurred, as well as by documenting the corresponding relaxation magnitude. One method of addressing relaxation when it is encountered is to drive the foundation piles to a greater end of initial driving capacity than required long-term. Hence, the identification and quantification of the relaxation magnitude will be beneficial to foundation designers installing similar pile types in similar subsurface conditions. The paper will also present pertinent observations and recommendations on mitigating relaxation when encountered. INTRODUCTION One of the earliest observations of a decrease in redriving resistance following initial driving was reported by Miller (1937). He reported that piles driven into a saturated, coarse grained soil could lose 40 to 50% of their resistance when redriven 24 hours after initial driving. Yang (1956) similarly reported that after a break in driving, a decrease in driving resistance could be encountered for piles driven in dense fine sand, inorganic silt, or stiff fissured clay. Parsons (1966) in his paper that described piling difficulties in the New York City metropolitan area termed this phenomenon “relaxation”. In this time period, pile capacity was most often evaluated from a pile driving formula frequently checked by a static load test. Hence, the true magnitude of the capacity decrease on a given pile was often poorly quantified. Furthermore, dynamic measurements that could determine what influence driving system performance variation had on the observed redriving resistance were not yet readily available.

Jan 1, 2019

By Chu E. Ho, Paul Napoli

A new waterfront park was developed on Long Island in close proximity to the East River and Newtown Creek. The existing ground consisted of fill over soft organic clay, medium dense silty sand, glacial till and schist bedrock. The ground was initially raised to preload the underlying soft soils to stabilize the ground in preparation for site development. The ground was subsequently cut down to temporary grades for installation of foundation piles for the overlook structures and construction of reinforced concrete cantilever retaining walls forming pathways located adjacent to the water bodies. The retaining walls were located in two rows at different elevations along the sides of a steep embankment. Where the pathways converge, some of the walls were too close to each other, and were redesigned as a combined U-wall with a common base slab. The individual retaining walls were designed for adequate bearing, sliding and overturning resistance. Ground anchors were installed to enhance global stability of the retaining walls. This paper presents the design considerations for the retaining walls for various loading conditions, and evaluation of the trial and proof tests for the anchors. INTRODUCTION The New York City Master Plan included the transformation of an approximately 30-acre parcel of land in Long Island City, Queens, New York from a former manufacturing zone into a residential, commercial and recreational zone for middle-income community. The site was located at Hunters Point South along the eastern shoreline of the East River and Newtown Creek (Figure 1). The development included low to high- rise residential buildings, a public school, and retail structures. Open spaces were provided along the East River and Newtown Creek waterfronts in the form of a continuous park providing for recreational and community-related activities. Waterfront structures included small park buildings, walkways and viewing platforms. The shoreline was surrounded by revetments as part of the flood mitigation strategy. The project involved extensive site re-grading and several retaining walls were constructed. The earthwork volume amounted to approximately 47,000 cubic yard of imported fill and 93,000 cubic yard of cut. The exposed height of the retaining walls ranged from 3 to 15 feet. This paper focuses on the design and construction of the retaining walls for the project.

Jan 1, 2019

By Vivek Samu, Murthy Guddati

A new method called Effective Dispersion Analysis of Reflections (EDAR) was recently developed to effectively analyze the dispersive waves generated from lateral impact to piles. This paper presents the results of nondestructive length estimation of existing piles through EDAR. EDAR provides a new visualization method for analyzing wave reflections by transforming the response into the frequency domain thus eliminating the need to perform difficult peak picking in the time domain. In addition to being able to analyze dispersive waves, EDAR also incorporates the effects of radiation damping due to the surrounding soil leading to more accurate length estimates. Concrete filled steel tubes of different embedment depths were tested both in laboratory and field conditions. Length estimates obtained were within 10% error margins after careful analysis accounting for the presence of soil effects and effects from pile top reflection.

By Bao K. Le, Khang T. Truong, Masaki Kitazume, Toru Kobayshi, Long P. Le, Tanaka Hitoshi, Makoto Kamimura, Hoang-Hung Tran-Nguyen

"Earth levees constructed using dredged materials taken from a river along an earth levee have annually damaged in the Mekong Delta due to high void spacing in earth levees and floodwater. Sliding and internal erosion due to floodwater or piping are two key factors causing earth levees’ failures. This study proposed to apply Deep Mixing Method (DMM) to reinforce earth levees in the Mekong Delta, Vietnam. The DMM creates a soil cement wall or soilcrete wall having better engineering properties such as higher strength and low hydraulic conductivity than those of the in-situ soils. The DMM can be applied to reinforce earth levees with limit additional materials that provinces in the Mekong Delta are difficult to supply. The study investigates capacity of the DMM to reinforce earth levees in the Mekong Delta, Vietnam against annual floods. Seepage and slope stability analyses under various conditions were performed with various scenarios of earth levee’s body. The analysis results indicate that the DMM can create a wall that cuts off piping across earth levee significantly and can improve stability against deep sliding due to rapid drawdown of the floodwater.INTRODUCTIONThe Mekong Delta produces agriculture products of 50% of the whole country even though the Mekong Delta has an agriculture area of 30% of the country (Wikipedia 2014). Rice is the main product for the domestic demand and export. This is the main reason why the local people want to cultivate rice 3 times per year to increase the total rice product for export. To do that, the local provinces have constructed earth levees surrounding each area of 100-200-hectare against annual floods to protect rice fields, and farmers can grow rice in the whole year. There are thousands of kilometers long earth levees in the Mekong Delta, and the local governments have spent millions of US dollars to repair and to maintain their earth levees yearly (reports of Dong Thap province 2012; 2014).Earth levees in the Mekong Delta have often failed in flood seasons (e.g., from August to December), especially in Dong Thap and An Giang provinces – the two provinces confronting directly the annual floods from the Mekong River when the floods reach the Vietnam land. The main failure of earth levees is piping, and then causing collapse of some section of an earth levee. An earth levee was usually constructed by piling up dredged materials along a river with minimum compaction. Subsequently, floodwater flows through connected void spacing and washes out soil particles in the body of an earth levee slowly to create piping. Annual wet-dry cycles make the top clay layer swelling and shrinking to form cracks that can store rainwater to trigger sliding (whitlow 2001; Ton That Vinh 2003)."

Jan 1, 2015

By Michael Frawley, Deana Ruud, Jessica Turner

Technology is allowing for new ways to mitigate risk associated with subsurface exploration and unanticipated subsurface conditions during construction. Unanticipated subsurface conditions have the potential to force delays and cost overruns on even the best-managed and well-executed projects. For more than a century, geotechnical professionals have documented the location and conditions encountered in hundreds of thousands of subsurface borings. Utilizing processes for compiling and managing data, owners can streamline site selection and receive access to a conceptual geotechnical model before field exploration takes place. Digitizing historical subsurface information allows for creation of an interactive, web-based platform combining publicly available information and culminating with the opinion of a local, experienced geotechnical engineer. This connectivity aids in the reduction of risks associated with unknown conditions on prospective project sites. Through this conceptual project study, we demonstrate how a project owner would be able to use a comprehensive desktop study to review the expected conditions prior to making a purchasing decision. Following the purchase, the expected conditions would be confirmed through traditional methods, confirming potentially problematic site conditions and the associated risks. INTRODUCTION Preliminary project planning is often based on assumptions made by the design team with regards to site suitability. After due diligence, site development is traditionally initiated by the owner or the owner’s representative when engaging a geotechnical engineer to perform a thorough subsurface exploration at a site. The data generated by the geotechnical engineer’s analysis of the site is required to design foundations, pavements and earth retaining structures and move the project from concept into design. This necessary, subsurface exploration can be time consuming, intrusive, and require significant resources, often when resources during construction seasons when resources are most limited. By leveraging historical data generated from previous subsurface exploration, a more thorough analysis of project risk can be developed prior to mobilizing a drill rig. Ultimately, preliminary budgets and designs are more accurate and geotechnical field exploration is more strategic. The geotechnical engineer’s role transforms from raw exploration and analysis to confirmation of anticipated conditions.

Jan 1, 2019

By Chang-Yu Ou, Shao-Chi Chien, Hsuan-Hsiang Chang

"A field test was performed to investigate the applicability of electroosmosis with the injection of saline solution of Taipei silty clay. The calcium chloride solution and sodium silicate solution were used as the saline solution for the injection in this test. The results of this study indicate that injection using calcium chloride solution and sodium silicate solution during the electroosmosis to increase drained water from cathode and electro-chemical reaction can greatly improve the effect of electroosmosis and shorten the time of treatment. The results of field vane tests showed that the undrained shear strength after treatment increased an average of approximately 120% for a treatment period of 24 days.INTRODUCTIONThe first field application of electroosmosis in soil was demonstrated by Casagrande in 1939. Since then, more complete field applications of electroosmosis such as Bjerrum (1967), Fetzer (1967), and Lo et al. (1991b) have been made.The results of field electroosmotic work for a period of 120 days were presented by Bjerrum et al. ( 1967). The mean undrained shear strength, Su, increased from 18 to about 40 kPa, with a uniform surface settlement of about 0.5 m. Lo et al. (1991b), with a more sophisticated installation and a relatively larger spacing, also had positive results. For a 3 m electrode spacing during the treatment of a period of 33 days, the mean Su increased from 18 to about 25 kPa. Although the effect of the electroosmosis could be applied in the field based on the above examples, the response remained slow. For actual field work, the application of electroosmosis will be limited due to short project schedules and request of the effect of improvement."

Jan 1, 2005

By M. D. Riegel, Brian T. Felber

"Construction of foundation elements in an urban environment is often complicated by multiple constraints such as existing foundations, utility conflicts, maintenance and protection of traffic on high volume roadways, low overhead clearances, and vibration and displacement monitoring to reduce risks of impact to existing facilities. Micropiles are commonly a preferred foundation alternative in an urban setting to mitigate some of these risks. This paper presents examples in which micropiles helped reduce risk in an urban setting on the two subject infrastructure improvement projects. The case studies presented include the Verrazano Narrows Bridge HOV and Bus Ramp Improvements in Brooklyn, NY and the Kosciuszko Bridge Replacement in Queens and Brooklyn, NY. The paper details the micropile design, how risks were mitigated, and the complications to each of these projects associated with the urban setting.INTRODUCTIONThe paper begins with background information about the Verrazano Narrows Bridge HOV and Bus Ramp Improvements Project, followed by background information for the Kosciuszko Bridge Replacement Project. This introductory background information is followed by discussion of the urban site constraints, which controlled the foundation type selection for both projects. In closing, the paper discusses the micropile design process, load testing, and construction.VERRAZANO NARROWS BRIDGE HOV & BUS RAMP IMPROVEMENTS BACKGROUNDProject ScopeThe project consists of two new ramps; one designated for HOV / Bus traffic between Staten Island and the Gowanus Expressway, and one to be utilized for storing the barrier transfer vehicle. Also included is the complete reconstruction of Ramps B and F to accommodate horizontal and vertical alignment clearances from the new ramps, removal of the median of the upper level to add one lane, utilities improvements, stormwater improvements, and miscellaneous structural repairs. The new HOV / Bus Ramp was designed for reversible traffic flow to accommodate the demand of the peak traffic direction by movable barrier.Geotechnical / Foundation Engineering ScopeThe geotechnical work included a desk study review of existing plans, geotechnical reports, and geologic maps. This data was subsequently supplemented with a subsurface exploration program. Once completed, foundation design was performed for 25 proposed bridge substructures. Four existing battered pilesupported foundations and two shallow foundations were evaluated for increased loading. Upon completion of the foundation design, foundation plans, specifications, and an engineer’s estimate were prepared. Foundation installation was observed on a part-time as needed basis."

Jan 1, 2016

The intent of this manual is to provide guidelines for inspectors of drilled shaft construction otherwise referred to as drilled piers, caissons or bored piles. It should also be helpful to train beginning geotechnical engineers with limited first hand experience or for geotechnical engineers who are training inspectors. It is expected that the general guidelines and procedures described here will be supplemented by local geotechnical engineers working in a particular region based on local practice and experience. Since drilled shaft construction procedures vary widely based on local geology and size of project, an all-inclusive manual is not considered practical. This manual focuses on traditional topside inspection for routine drilled shaft construction. Other inspection and evaluation methods that rely on electronic equipment are available, but these methods require extensive training and experience in the interpretation of results. These more sophisticated methods of drilled shaft inspection and evaluation are common in construction, but they are usually provided by specialty subconsultants. The subconsultant will typically submit a report for each shaft, which will be reviewed by the geotechnical engineer. Other manuals are available to describe the electronic methods of drilled shaft inspection.

Jan 1, 2004

By G. Stuart Littlejohn

In spite of recent concerns in certain European countries, I believe that silicate-ester grouts will continue to be employed in practice, unless more cost-effective inorganic grouts are developed for the treatment of fine sands. It is also noteworthy that over the past 40 years, there has been a record of good experience where silicate-ester grouts have been used in ground improvement. Nevertheless, there is now a need via the European Standard EN 12715 (2000) "to assess the environmental impact, particularly the toxicity of the grout and grout components, and their effect on ground and drinking water should be considered before grouting." "When testing the grouting material for environmental impact, the following aspects should be considered: ? Whether during processing, transport or grouting, substance can be generated or released which could be hazardous to the environment or the grouting crew; ? Whether noxious substances can spread upon mixing with ground water; ? Whether reaction products can be produced or released which influence the water quality; ? The type of particles eroded from hardened grout; ? Chemical reactions between hardened grout and the ground water."

Feb 10, 2003

By Sam Warren, Antonio Marinucci, Genesis Z. Figueroa, Anne Lemnitzer

Drilled Displacement Piles (DDP) provide an ideal deep foundation solution that combines the benefits of ground improvement with traditional advantages of piling systems. This paper consolidates data from 20 construction projects in which more than 30 DDPs were installed and tested axially. High quality site exploration data (e.g., Cone Penetration Test and Standard Penetration Test) were evaluated to derive geotechnical analysis parameters. The test sites consisted of mostly mixed soil types with strongly stratified layers of sand, silt, and clay. Pile diameters ranged between 40 cm and 61 cm. Test results were compared with predictive methods developed specifically for DDPs as well as methods used in general geotechnical practice. The accuracy of the empirical methods is presented in terms of total pile capacity, pile length/diameter, and soil type. The large majority of all examined methods underpredict the in-situ pile capacities. It was also found that the difference between the tested and predicted capacity is strongly related to the level of improvement in the surrounding soil due to the piles’ installation. A general comparison between predictive axial accuracy and the observed level of ground improvement upon installation is also discussed.

May 1, 2022