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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 Fred Tarquinio, Giovanni Bonita, Lars Wagner

"A new embassy for the Peoples Republic of China is under construction in Washington, DC. The 475,000 square feet (44,125 m2) structure has five levels below ground and four above, making it the largest embassy in Washington DC. A vertical soil nail wall was used as the primary support of excavation system for the project. The soil nail wall was irregularly shaped, benched in areas, and up to 98 feet (29.9 m) in height. The soil nail and shotcrete system consisted of approximately 1,600 soil nails and 50,000 square feet (4,645 m2) of exposed shotcrete wall surface. Design and construction challenges included soft soil conditions, inside wall corners, underground utilities, seismic impacts from blasting, and logistical and political factors. Overall, wall movements were lower than expected, with maximum horizontal movement less than 0.25% of the total height of the excavation. INTRODUCTIONThe proposed Embassy of the Peoples Republic of China in Washington, DC, will consist of about 475,000 ft2 (44,125 m2) of building space and contain up to four fl oor levels above ground and fi ve levels of basement (Figure 1). When completed, the building will be the largest embassy in Washington, DC. The architect for the project, Pei Partnership Architects, along with the world-renowned architect I.M. Pei, made effi cient use of the site by inserting the building into the existing slope. Consequently, excavations reach heights up to 98 feet (29.9 m) on the southern side of the property and 42 feet (12.8 m) on the northern side.The soil nail and shotcrete system consisted of approximately 1,600 soil nails and 50,000 square feet (4,645 m2) of exposed shotcrete wall surface. The location of the building relative to the property line called for tight excavation requirements, including precise wall positions and shotcrete tolerances. Design and construction challenges included soft soil conditions, inside wall corners, arched walls, underground utilities, seismic impacts from blasting, and logistical and political factors."

Jan 1, 2007

By Yoshinori Kurumada, Masaya Watanabe, Kenji Sasa

"The Port of Yokohama is strengthening its international competitiveness as a strategic container port in order to respond appropriately to global exchange and shipping demands. Thus, the Minami Honmoku main Pier is currently being developed. The high-standard container terminals MC-1 and MC-2 have already started their service, and the development of the container terminals MC-3 and MC-4 is currently in progress.Because the South Honmoku Pier plays an important role in waste disposal management of Yokohama, a final waste disposal site (controlled final landfill site) is being developed in Block 5 to provide long-term and stable reception of waste that will be generated in the city. For this project, a revetment with water-blocking properties and an extension approximately 1.7 km in length is being built in order to prevent water from leaking from the disposal site. The base part of the revetment will be subjected to foundation improvement using the Cement Deep Mixing (CDM) method in order to secure water shielding of the soft sediment underneath the water, prevent slipping of the seawall, reduce the amount of subsidence, and increase the foundation support force.This report presents a preliminary study on using CDM on reclaimed soil and the construction process of the development project of the disposal site in Block 5 of the Minami Honmoku Pier, which has been underway since 2007.ABOUT MINAMI HONMOKU PIERThe development of the Minami Honmoku Pier started in 1990. It was designed to develop high-standard berths with greater water depths in order to handle the increasing volume of foreign container cargo and growing size of vessels. Figure 1 shows the layout of Minami Honmoku Pier. In April 2001, the Phase 1 (MC-1 and MC-2) began services. This is the newest pier in Port of Yokohama.This pier has one of Japan’s largest terminal areas (40 ha) and is equipped with 22 row-type mega gantry cranes capable of handling the newest ultralarge container ships. The pier has a quay with a water depth of 16 m, which is the first in Japan. The pier is equipped with advanced facilities and equipment to let Port of Yokohama be internationally competitive and function as an international commercial hub. An innovative system for high-efficiency transport is currently being introduced; it includes the installation of waiting vehicle lanes and a reservation-based loading and unloading system.Since the fiscal year 2007, a new container terminal (MC-3) with a -20m deep quay capable of handling the increased size of container ships and the diversification of port logistics has been under construction and is nearly completed."

Jan 1, 2015

By Ping Yang, Tian-bin Li, Min-hui Wu

"The process of filtrate loss of low solid-phase drilling fluid at different content of polyanionic cellulose is investigated by the standard filtration test. The test results showed that when time of filtration is same, the filtrate volume decreases linearly with the increase of content of polyanionic cellulose. When content of polyanionic cellulose is same, the velocity of filter loss decreases nonlinearly with the increase of time and the velocity of filter loss will reach a stable value. The filtrate volume in 7 to 8 minutes can reach half of the total filtrate volume. At the same time, the velocity of filter loss of drilling fluid decreases nonlinearly with the increase of viscosity. When apparent viscosity is between 3.5~4.15 mPa.s, decrease speed of velocity of filter loss is quick. The results are helpful for characteristics evaluation of filtrate loss of drilling fluid and control of filtrate loss.IntroductionDuring the process of drilling, water of drilling fluid can leakage into stratum, the water can result in instability and collapse of borehole wall. At the same time, the original ratio of drilling fluid will change. The density of drilling fluid will increase, the performance of the drilling fluid will change. Controlling amount of filtration is important to drill successfully. The additives of controlling filtrate loss are mainly two types, particle materials and polymer materials. High-molecular polymer is a kind of high-molecular material, has the adsorption effect, high polymer protection, can improve the advantages of slurry viscosity (Xu,2004 and Dehghanpour,2001). Some scholars carried out some study on the polymer material fluid loss agent in recent years, these study mainly focused on CMC, HEC, MHEC, CMHEC, starch and its derivatives(Zhang,2005 and Chevron,2009).About PAC (polyanionic cellulose) as drilling mud additives, a few of scholars carried out some relevant work. Plank (1992) applied PAC into ordinary freshwater drilling fluid and analyzed temperature stability of freshwater drilling fluid. Bennion (2000) applied PAC into drilling fluid and analyzed effect of polyanionic cellulose on strata inhibitory. Huang (2011) analyzed effect of PAC on properties of the high-density water-based drilling fluid. Mahto (2004) applied PAC into fresh water and salt-water drilling fluid and analyzed effect of PAC on rheological properties of the drilling fluid. Wang (2008) applied PAC into alkaline drilling fluid to study various performance of drilling fluid. PAC is a renewable resource and has good application prospect (Ankara, 2005). So it is very important to understand the effect of PAC on filtration process of drilling fluid.The test was conducted by changing the content of the PAC in drilling fluid. The object of this paper is to understand effect of polyanionic cellulose on filtration process of the low solid-phase drilling fluid."

Jan 1, 2017

By Salim Mezazigh

Usually different methods for designing a single pile submitted to a lateral loading are available. They are based on theory of elasticity with the parameters E,v or subgrade reaction method using the p-y curves. The subgrade reaction methods are commonly used. They allow determining the efforts exerted along the piles and their corresponding displacements. Before any design the reaction curves P-y must be well defined for each foundation soil layer. These curves link the pile horizontal displacement y to the subgrade reaction of soil P. Different in situ tests such as the static penetrometer or the pressuremeter give a possibility to get the P-y curves in the case of a single pile installed in sand with an horizontal surface and statically laterally loaded. These ideal conditions are not always respected on the site around the pile if appear slopes, embankments, or buildings... The behaviour of such configurations of piles is more sophisticated due to the proximity ( slope, embankment, earthworks, buildings,..). A research program has been conducted to determine the influence of a slope on the P-y curves by centrifuge modelling. The centrifuge tests constitutes an experimental approach allowing parametric studies in respect with similitude laws in geotechnique. Before all, repeatable tests have demonstrated that the test conditions, the instrumentation equipment and the installation method for piles are well controlled. By this way, the obtained results from centrifuge tests can be transferred to the prototype i.e. the in situ piles. Many tests have been performed on piles in sand to determine the influence of a pile on the p-y curves. The main objective is to give for practice some coefficients to apply to p-y single pile curve to take into account the proximity slope effect. Here the experimental set up is described and in particular the proximity slope effect is discussed. Deduced subgrade reaction reduction factors are proposed for piles in sand under lateral loading.

Jan 1, 2002

By Takashi Enomoto

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

Jan 1, 2015

By Filippo Maria Leoni, Wesley Schmutzler

"Deep Mixing Method (DMM) for the Rio Puerto Nuevo Project in San Juan was chosen by the Corps of Engineers to improve the soils adjacent to a 90 inch forced sewer main relocation and to improve the soils for the base of a new drainage channel. The project is located just east of San Juan and south of the Horizon Port. The soils to be improved consisted of fill, marine clay, organics (peat) and the foundation clay layer. A preconstruction soil investigation campaign was performed to assess soil properties and to retrieve samples of the different soil layers for the laboratory Bench Scale Testing program (BST). The BST was conducted using various binder contents and water/cement ratios in each of the soil types; the selection of the different combinations and dosages was based on past extensive experiences on similar materials. Following the laboratory program, a full scale Field Test (FT) was done installing several DMM elements to verify the results of the BST and fine tune the construction parameters. Each element consisted of two 5.5 feet diameter overlapping mixing augers installed simultaneously to a depth of approximately 60 feet using a SOILMEC SR-90 dual axis drilling rig. The FT construction and post-construction coring results showed significant differences between the lab study and the actual field conditions. This paper will highlight these differences and the importance of performing both pre-construction laboratory and field tests in order to ascertain the proper mixing parameters in the different soil layers.IntroductionThe Puerto Nuevo project consists of the stabilization of a major drainage channel using Deep Mixing Method (DMM) and the relocation of a 90 inch forced main sanitary sewer outfall. The first portion of this project was a 40 x 16 x 2,000 foot box culvert installed in 2004. In order for the drainage system to be completed and function properly, the 90 inch forced main needed to be lowered about 20 feet 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 overall layout of the project is shown in Figure 1. The DMM is 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 and B as an example. (Figure 2) The total amount of soils to be treated by DMM is approximately 84,000 cubic yards up to a maximum depth of 57 feet from ground surface and an Area Replacement Ratio of 100%.The equipment used to perform the DMM is a Soilmec SR90 twin-shaft jet assisted deep mixing rig (Figure 3) coupled with a LODOS 30 grout plant and two Soilmec 7T-500J high pressure pumps."

Jan 1, 2015

By K. Ronald Chapman, Claus Ludwig, Doug Jenevein

"In the spring of 2005 Schnabel Foundation Company completed a $15.2 million Design/Build subcontract to underpin 11 structures, and provide 202,800 square feet of earth retention for the Reno Transportation Rail Access Corridor (ReTRAC) project in Reno, Nevada. Schnabel’s work was part of a Design/Build contract to depress a railroad alignment through downtown Reno. The depressed section was 2.2 miles long, 54 ft wide, and up to 35 ft deep (3.5 km long, 16.5m wide and up to 10.7m deep). The trench structure was required to be watertight. SUBCONTRACT WORK OVERVIEWEleven buildings along the track alignment required underpinning. Three types of underpinning were used, designated Type 1, Type 2 and Type 3.At four buildings the trench retaining walls were to be located directly under the exterior footings. This alignment eliminated traditional underpinning and cut-off wall techniques that could normally be used to support structures. Type 1 underpinning was used at these buildings. This underpinning system consisted of a combination of permeation grouting, hand-dug piers, and permanent tiebacks. This underpinning system became the new watertight trench walls.Five buildings were located a few feet behind the trench walls, and their exterior walls were supported by continuous footings. Type 2 micropile/pile cap underpinning (patent pending) was used to support these buildings.The remaining two buildings were also located a few feet behind the trench walls, but they had column footings along the exterior walls. At these structures traditional micropile underpinning was provided through the existing footings. This is described as Type 3 underpinning.Temporary earth retention was required on both sides of the trench along most of the alignment. This shoring supported frontage roads, private property and surcharge from the temporary railroad shoofly running parallel to one side of the trench.SUBSURFACE CONDITIONSThe soil along the trench alignment consisted of river outwash deposits. The top 2 to 18 feet (0.6m to 5.5m) generally consisted of flood plain silt and sand deposits, or fine-grained fills. These fine-grained soils are underlain by the Tahoe Outwash Formation which consists of interbedded layers of sand; sand and gravel; and sand, gravel, cobbles and boulders. Some of these layers encountered during construction consisted of 30 to 50 percent cobbles and boulders, with some boulders up to eight feet in diameter.A major challenge to the design and construction of the trench structures and the underpinning was the ground water table which was 10 feet (3m) above subgrade in the deepest portions of the trench. Based on specification restrictions, temporary and permanent dewatering was not feasible. As a result, the selected design and construction methods had to consider three water conditions: the anticipated groundwater level during construction (CGW), the groundwater level for permanent design (DGW), and an additional special design condition with water at street grade."

Jan 1, 2006

By David R. Sutfin, Joseph Lodde

110 N. Carpenter is new commercial building located in the West Loop neighborhood of Chicago, Illinois. The new home to the McDonalds Corporation work headquarters, accelerated project delivery methods were essential to meet the scheduling demands for this project along with other projects slated to start in the region. As such top-down construction methods were utilized to allow for above and below grade construction to proceed in parallel in lieu of more conventional bottom-up construction methods, thus compressing the project schedule. To achieve this plan, perimeter secant pile walls were constructed in conjunction with interior columns/drilled shafts and a shear wall core constructed from inside a temporary cofferdam. The use of secant pile walls allowed for efficient accommodation of a variety of loading conditions including: exterior curtain walls loads, perimeter column loads, tower crane foundation loads, and in-plane shear loads. Furthermore, this system allowed for efficient and fluid operation of equipment on site in order to accommodate the 90-day window allotted for initial foundation construction. INTRODUCTION 110 N. Carpenter is a recently-constructed 9-story commercial building located on the old Harpo Studios property in the West Loop neighborhood of Chicago, IL. The construction of this 55,750m2 (600,000 ft2) structure is significant to the continued commercial development of Chicago as nearly 46,450m2 (500,000 ft2) of the building houses the new world headquarters for the McDonald’s Corporation, which had moved from Chicago to the suburb of Oak Brook in 1971. McDonald’s recommitment to this urban environment is not only a reinvention of the long-established fast food giant but the anchor for a broader redevelopment of the West Loop neighborhood. Since the opening of this building was seen by the developer, the City of Chicago and others as a key to future local projects, innovative solutions were required to showcase forward-thinking design as well as expedite the construction process. The final result of the design/planning process is a structure consisting of nine levels of above-grade commercial space and two levels of below-grade parking, providing approximately 300 parking spaces. The above-grade structure consists of a reinforced concrete flat plate system, including two-way slabs, columns, and two core/shear wall systems for lateral support. With an average depth of 7m (23ft), the below-grade structure consists of interior components similar to the above-grade structure (structural slabs, columns, shear walls) but includes a perimeter secant pile wall that was designed to support lateral earth pressures; vertical forces from the exterior curtain walls, perimeter columns, and the construction tower cranes; and in-plane lateral forces to reduce the demand on and quantity of interior shear walls. The use of a secant pile wall is a key component to the project because it accommodated the use of top-down construction methods to accelerate the construction schedule.

Jan 1, 2019

By M. Hesham El Naggar, Maged A. Abdlrahem

"Hollow bar micropiles have constructional advantages such as: fast and low-noise and low vibration installation process and small installation equipment, which allow access to tight places. In addition, they have efficient load transfer mechanism, which facilitates carrying considerable load in compression and tension. The common practice is to use diameter ratio of drill bit/ hollow bar (Db/Dh) around 2 in their construction, and they are typically designed assuming type B as classified by the Federal Highway Administration (FHWA). In this paper, the performance and capacity of Hollow bar micropile with different (Db/Dh) ratios are investigated. Full-scale micropiles were installed at a site in Ontario, Canada, and were tested in order to evaluate the uplift performance of Hollow bar micropile with different(Db/Dh) ratios. Two micropiles with two different ratios 2.25 and 3 were constructed and tested. The total length of the micropiles was 6m with embedded length of 5.75m. The soil at the site was primarily medium dense to dense sand. The results of the load tests are presented and discussed. It was found that the uplift capacity of the micropile increased by about 19.5% as Db/Dh increased from 2.25 to 3.INTRODUCTIONMicropile is a small diameter, less than 300 mm, drilled and grouted pile and is typically reinforced according to Federal Highway Administration (FHWA, 2005). The technology of micropile was introduced in North America in 1970’s, but the growth in the east coast of United State was intense compared to all other cities around the globe (Bruce and Nicholson, 1989). Nowadays, micropile construction is used extensively worldwide as a viable solution that offers several advantages such as fast installation in low headroom, minimal disturbance to the adjacent structure efficient load transfer due to high grout to ground bond strength. As the method of grouting has major influence on the grout – ground bond strength, FHWA has classified the micropiles into four categories. Type A: the grout is placed under gravity and no pressure is required. Type B: The grout is typically pressurized under a pressure range from 0.5 to 1 MPa as the temporary casing is withdrawn. Type C: the grout is placed in two-step process. First, the grout is poured under gravity only as in Type A. Before the hardening of the grout, similar grout is pressured of at least 1MPa without the use of packer. Type D: Like Type C, it is a two – step process, the grout is placed under gravity as in Type A and sometimes pressurized as in Type B. After hardening of the initial grout, additional grout is pressurized between 2 to 9 MPa through sleeved pipe by using packers, as many times as needed. According to this classification, hollow bar micropile is usually designated as Type B. However, the construction technique is completely different from Type B. Recently; there is a trend to supplement the four types of micropiles by Type E as represent to hollow bar micropile (Timothy et al, 2012). The construction method of hollow bar micropile involves two main stages which can be performed in one–step process: advancing the drilling bit attached to a threaded hollow bar to the required depth; and pressurizing the grout through nozzles of the drill bit."

Jan 1, 2016

By Darrell L. Beddard

The test program information provided for some immediate changes on the upcoming contracts and in contract administration for the I-880 Replacement Project. Plan sheet modifications included changes to the pile data tables showing the actual demand load required for structural stability. The normal class of pile with a minimum load carrying capacity was removed. This provided for substantial pile length reduction at several locations since the structural loading was much less than the predetermined pile class ultimate capacity. New specifications were developed and standard specifications were modified to accommodate the newer foundations, installation procedures and pile acceptance criteria. Current Caltrans specifications require that the Contractor provide bearing capacity at the specified tip elevation. This requirement was removed and pile acceptance was determined by the Engineer. Acceptance criteria was established by the State and was based on. set-up trend over time. Static loading tests were reduced especially in areas where testing was performed on the indicator program. Testing procedures were modified and set-up periods were established before piles could be tested. For the contract near the San Francisco Oakland Bay Bridge (Unit E) the FHWA 1000 tons (8.9 MN) test beam configuration was completely changed. This provided added safety and allowed more tolerance in the pile placement for the testing operations. Indicator piles were added as companion piles to the static loading test piles. These piles were used for restrike events which included collecting dynamic data for calibrating the wave equation analysis with static load test results. Indicator piles also provided quick access for restrike events, where as, the static loading test pile needed modification to perform the restrike operation. Penetration rates were recorded for these operations. Wave equation Analysis Program (WEAP) was used in developing the acceptance criteria. The standard Engineering News Record (ENR) formula in the current Caltrans' Standard Specifications was removed for the contracts. Contractors were required to submit, prior to driving piles, a driveability study for their contract. These studies required discussion of their operations, method of installation, effects of soil set-up, set periods, hammer settings, bearing graphs, inputs to the WEAP program and complete a "Pile and Driving Equipment Data" form. Dynamic monitoring was detailed in the specifications on how the monitoring process was to occur. Set periods were established and restrike events were called out with the frequency of these events.

Jan 1, 1996

By H. Cheng

The Bohai Oil Company has applied all together 11 jack-up oil drilling rigs (movable platforms) (1) which can be classified in terms of their forms of foundations into two types: the integ­ral mat and the column legged, as demonstrated in figure 1. Figure 1 a) indicates the entire structure of the sunk cushion type, i.e. the one with a box-like sunk cushion serving as its foundation by directly sitting on the sea bed. The length, width and height of the outer sides for the sunk cushion stand at 45.8 x 38.0 x 3.3m ( for Rig Bohai No.2 ) and 50.6 x 33.2 x 4.88m ( for Rig Bohai No.6 ), the relative areas of theirs being 1475m2 and 2008m2 respectively and both bigger than the plane areas of the rigs. With a view to realize a convenient drainage of mud while sinking, two holes of 14 x 14m and 32 x 18m in size are constructed in the center part of the sunk cushion. When work sets off, the underside of the sunk cushion operates as a foundation, the sunk cushion being connected to the platform by hull columns which transmit the load of the platform down­wards to the sunk cushion that passes it further onto the subgrade. [ ] Column legs for rigs may also be grouped into two categories considering their features: columns with and without boots. The bodies of boot columns are made up of trusses, whose bottoms, are boot-shaped with a big diameter. The diameter of boot columns of the rigs applied by the Bohai Oil Company shows bigger and it may reach 12 or 18m. In the boot columns, the transmission of the platform's weight into soil is done by the underside areas of boots. While in the case of the vertical columns, which are of cylinder columns of steel with sealed bottom ends shaped inverted arch, the entire drilling platform is supported by the carrying force delivered by the bottoms of these steel cylinders and the frictional force rendered by their outside walls. Such a type of columns is featured by a small diameter, 3m in general. Figure 2 exhibits the schematic diagram of sections regarding the two types of column legs.

Jan 1, 2010

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

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

Jan 1, 2016

By Fred Tarquinio, Giovanni Bonita, Lars Wagner

"A new embassy for the Peoples Republic of China is under construction in Washington, DC. The 475,000 square feet (44,125 m2) structure has five levels below ground and four above, making it the largest embassy in Washington DC. A vertical soil nail wall was used as the primary support of excavation system for the project. The soil nail wall was irregularly shaped, benched in areas, and up to 98 feet (29.9 m) in height. The soil nail and shotcrete system consisted of approximately 1,600 soil nails and 50,000 square feet (4,645 m2) of exposed shotcrete wall surface. Design and construction challenges included soft soil conditions, inside wall corners, underground utilities, seismic impacts from blasting, and logistical and political factors. Overall, wall movements were lower than expected, with maximum horizontal movement less than 0.25% of the total height of the excavation.INTRODUCTIONThe proposed Embassy of the Peoples Republic of China in Washington, DC, will consist of about 475,000 ft2 (44,125 m2) of building space and contain up to four fl oor levels above ground and fi ve levels of basement (Figure 1). When completed, the building will be the largest embassy in Washington, DC. The architect for the project, Pei Partnership Architects, along with the world-renowned architect I.M. Pei, made effi cient use of the site by inserting the building into the existing slope. Consequently, excavations reach heights up to 98 feet (29.9 m) on the southern side of the property and 42 feet (12.8 m) on the northern side.The soil nail and shotcrete system consisted of approximately 1,600 soil nails and 50,000 square feet (4,645 m2) of exposed shotcrete wall surface. The location of the building relative to the property line called for tight excavation requirements, including precise wall positions and shotcrete tolerances. Design and construction challenges included soft soil conditions, inside wall corners, arched walls, underground utilities, seismic impacts from blasting, and logistical and political factors.SITE INVESTIGATIONInformation obtained from the geotechnical investigation revealed about 10 to 20 feet (3.1 to 6.1 m) of a loose to medium dense fi ll material placed during previous site activities. The fi ll material was underlain by a silty sand and sandy silt residual soil derived from the natural weathering of the underlying bedrock. This soil sequenced naturally from a medium dense to very dense material through natural weathering of the underlying bedrock. This soil sequenced naturally from a medium dense to very dense material through natural weathering processes in the rock. The underlying bedrock was locally characterized as a gneiss. A water table elevation about 17 feet (5.2 m) above the fi nal excavation level was revealed, except in the “radius” area, where a leaking water main/hydrant generated a high local water table."

Jan 1, 2007

By Filippo Mira-Cattò, Andrea M. R. Pettinaroli, Elena Rovetto

"The construction of Powisle station of Metro Warsaw Line 2, in Poland, required the execution of two shafts next to an urban road tunnel adjacent to the Vistula River. The shafts were linked by three conventionally mined tunnels to be excavated 10 m below the water table level, into an upper sandy and sandy silty layer and a lower stiff clayey stratum. After a failed dig attempt under the protection of jet grouting and forepoling, it was decided to deal with the tunnels excavation problem by using the ground freezing technique as a temporary, non-polluting geotechnical treatment, keeping in service the upper road tunnel. The planning of the activities and the executive phases had a significant importance for the success of the work. For work scheduling reasons the mixed system was adopted, i.e. using both the liquid nitrogen system and the brine freezing method. The freezing process management, with a real time evaluation of the soil temperature measured by thermometric strings and an accurate monitoring of the overlying road tunnel structure, allowed the tunnel excavation and lining stages to be performed under difficult conditions, without water leaking from the frozen ground shell, within the expected times and saving extra costs.INTRODUCTIONThe new Underground Line 2 in Warsaw connects the eastern and western part of the town. One of the most critical interferences was the under passing of the Vistula river and of the Wislostrada motorway tunnel, a very congested motorway along the western bank of the river, with the construction of the new station Powisle. The construction of the station required the excavation of two shafts, using the top-down system with the creation of intermediate slabs while deepening the excavation.The shafts were used for the extraction of four Tunnel Boring Machines (TBMs), two approaching from the Vistula river side (east-side) and two approaching from downtown (west-side); in order to connect the two shafts was foreseen the realization of three tunnels, two for the underground lines and the central one for the exchanging passenger platform. These tunnels were underpassing the “Wislostrada Road Tunnel” and interfered with this tunnel foundation, which consisted of diaphragm walls (DW), the “barrettes” (Figure 1).Due to the variable geological conditions at the site, the first excavation stage, with a temporary underground support constructed of horizontal jet grouting columns and forepoling, caused the North tunnel face failure, that required an immediate filling of the empty cavities with lean mix concrete under the Wislostrada tunnel slabs. Thereafter, the recovering attempt with the grout injections could not be completed because of the development of heaves induced on the tunnel structures (Bringiotti et al. 2016). In those conditions the tunnel excavation with traditional technologies appeared to be very problematic, with high risk for the structural safety of the Wislostrada tunnel. This would have meant longer duration for the works and higher costs for the General Contractor as well as for the city Council."

Jan 1, 2015

By Debra F. Laefer

Jet grouting is a ground improvement technique that has become widely adopted over the past three decades, yet relatively little data has been published about performance characteristics of mixes under adverse conditions, such as the inclusion of clay lenses. This paper presents an experimental investigation on the impact of clay on the strength of jet grouting. A total of 150 grout samples were subjected to 0-10% levels of Kaolinite and Bentonite inclusion. While the Bentonite was introduced as a pre-hydrated slurry, the Kaolinite was mixed in two ways: in a pulverized condition and as large chunks. Sample strength and stiffness were measured at multiple dates within the first 28 days. With 10% clay inclusion all samples exhibited significant strength and stiffness losses. With some, substantial losses began with as little as 4% clay. Even a 1% clay inclusion tended to decrease strength and stiffness between one-quarter and one-third of the control sample. Depending upon clay type and inclusion method, results differed significantly with respect to strength and stiffness development and failure mechanism. Petrographic analysis is used to provide further insights as to apparently divergent behaviors.

Jan 1, 2009

By Edmund J. Cardoza

The Detroit Water and Sewerage Department (DWSD) provides water and wastewater services to the Greater Detroit Metropolitan Area. Sewerage is treated at the DWSD Wastewater Treatment Plant (WWTP) located at 9300 W. Jefferson Street south of the City of Detroit, Figure 1. PARTICIPANTS Engineering and design of the project for the DWSD was performed by Harza Engineering Company, Inc., C.C. Johnson & Malhotra, P.C. and their sub-consultants, including Worley Engineering and Wade Trim. The Prime Contractor is a Joint Venture of Traylor Brothers, Inc. and Jay Dee Construction. The shaft drilling and riser installation was performed by The Millgard Corporation in joint venture with the Prime Contractor (MTJD). The selection of specialized drilling equipment and the supervision and performance of the access shaft and riser installations was primarily the responsibility of The Millgard Corporation (TMC).

Jan 1, 2001

By Dan Brown

This paper provides an overview of the advantages and limitations of continuous flight auger (CFA) and drilled displacement (DD) systems compared to other deep foundation systems, along with a summary of important considerations for selection and design. Geotechnical and project considerations are described which favor the use of CFA and DD piling, and also which may be problematic for this type of construction or which may limit the practicality and competitive advantages. A brief summary of design methods for axial and lateral loading is included.

Jan 1, 2005

By Dempsey S. Thieman

The Kuparuk River Central Channel Bridge on the North Slope of Alaska provides critical access for oilfield service vehicles in the largest oilfield in the United States. The original sloped spill-through bridge abutments were protected by articulated concrete revetment. After 27 years of heavy service, ice impact, deep river scour, and high floods, the revetment required replacement. An OPEN CELL SHEET PILE® abutment was selected to replace the existing erosion protection and provide increased performance and structure life. Project engineers and contractors successfully addressed the challenges of low overhead sheet pile installation under the bridge, extremely heavy vehicle loads, and arctic winter construction conditions through innovative design and construction techniques. The project was successfully completed on schedule with minimal disruptions to critical bridge traffic. This paper provides a detailed discussion of the design and construction techniques utilized to address the challenges of the project, many of which could be adapted to other projects.

Jan 1, 2008

By Frederick C. Rhyner

The United States government sponsored the construction of a new vehicular bridge over the Diyala River in Bubriz, Iraq. This paper describes the geotechnical engineering for design and construction of drilled shaft foundations for this bridge. An Iraqi geotechnical engineering firm made borings and laboratory tests while analysis and design recommendations were provided in the United States. Despite the severe challenges of engineering in a war zone, excellent cooperation was the key to a successful effort. Three drilled shafts designs were necessary to accommodate the different subsurface conditions: a) medium-compact to compact sands, b) stiff to hard clays and c) mixed soil profile. The alpha and beta methods were used to estimate capacities for a conservative design, recognizing that quality control during construction might be less than what is normally provided in the United States. Iraq has a high seismic risk and LPILE was used to estimate the drilled shaft response during earthquake loading conditions. Settlement estimates were made using FHWA methods. Construction was carried out entirely by local Iraqi firms, despite the challenges of working in an active conflict area.

Jan 1, 2009