Search Documents

By Anthony T. C. Goh

"For deep excavations in soft clay, it is common to use jet grouting piles (JGP) prior to excavation to minimize wall deflections and ground settlement, and to prevent basal heave instability. In this paper, finite element analyses were carried out to assess the basal heave factor of safety for excavations in soft clay supported by JGP. Comparison of the factor of safety from the finite element analyses with limit equilibrium methods was then performed. Subsequently, to account for the uncertainties in the soil and JGP properties, a simplified reliability analysis procedure is proposed to estimate the probability of basal heave failure for deep excavations supported by JGP.INTRODUCTIONJet grout piles (JGP) are often used to prevent basal heave instability and to minimize excessive wall and ground movements associated with deep excavations in soft clay deposits (Shirlaw 2003; Wen 2005; Ou 2006). The jet grouting process which is carried out prior to any excavation works produces a series of short overlapping grout columns resulting in a “continuous” base slab (commonly termed as jet grout pile or JGP) below the final excavation level that spans across the entire excavation (Gaba 1990; Hsieh et al. 2003; Ho and Hu 2006). Typically, the JGP thickness ranges from 2 m to 4 m.The focus of this paper is on the assessment of basal heave instability for deep excavations in clay stabilized with JGP. Finite element analyses were first conducted to determine the basal heave factor of safety for deep excavations in clay with JGP. Comparisons were then carried out with factors of safety based on conventional limit equilibrium methods. Since the conventional factor of safety approach does not explicitly reflect the uncertainties of the soil and JGP properties, it is demonstrated in this paper that a simple reliability based approach (Hasofer and Lind 1974) can be used to assess the probability of basal heave failure.LIMIT EQUILIBRIUM METHODFor excavations is clay, the Terzaghi (1943), Bjerrum and Eide (1956) and Eide et al. (1972) methods which are based on bearing capacity theory, are commonly used to determine the basal heave factor of safety. Another commonly adopted method in Japan and Taiwan is the slip circle method which involves taking moments about the lowest strut level (JSA 1988; Hsieh et al. 2008; Luo et al. 2012). The slip circle method has also been applied for excavations with a JGP at the base by incorporating the undrained shear strength of the JGP. In the slip circle method, the basal heave factor of safety FSslip is assessed by taking moments about the lowest strut level (Fig. 1)"

Jan 1, 1900

By John D. Thornley

Alaskan villages typically store a one-year supply of fuel to reduce significant delivery costs. Alaska Village Electric Cooperative (AVEC), an electric utility cooperative providing power to 51 Alaska villages, has made a concerted effort to upgrade and improve their undersized and aging facilities. The Village of Stebbins, located south of Nome on Norton Sound is receiving upgrades to its AVEC bulk fuel facilities. Stebbins offered unique challenges from a foundations perspective due to the nature of the soil. The geotechnical investigation found the soil below roughly a third of the footprint of the bulk fuel facility to be thawed with seasonal freezing and the remainder was found to be warm permafrost with ground temperatures of between 30°F and 32°F. This is a unique and challenging arctic engineering design issue because foundations are designed differently for frozen ground conditions. Driven piles were selected because of site constraints, such as the design flood elevation and the change from thawed to frozen ground conditions. The pile design specified that the pile embedment depths would be selected based on the results of pile driving analyzer (PDA) testing during construction in the thawed ground and maintained within the frozen ground portion of the footprint. Difficulties during pile driving in the frozen ground resulted in several piles becoming severely damaged, requiring subsequent removal. This resulted in a reevaluation of the means and methods for pile installation. Additional fieldwork was performed to further characterize the subsurface soils and their frozen nature. Options for installation of piles in difficult areas were evaluated including ground thawing, predrilling, and reducing embedment depths. Presented within this paper are the findings from the initial and subsequent field explorations, discussion of the design methodology, and the decisions that led to successful installation of piles at this challenging remote village.

By R. H. Wright

This paper describes the design philosophy and methods employed in constructing the foundation elements for the Little Britain Project in the City of London. The Contract is a design and construct package for the foundations of a 3-storey basement which will be built using "top-down" construction techniques and is to be carried out by Fairclough Piling and Marine on behalf of Wimgrove Nominees. The Project includes 8000 sq.m. of diaphragm wall and barrettes 139 No. large diameter piles ranging from 900mm to 3000mm in diameter and up to 45m deep, and 9 No. cruciform barrettes for the heaviest column loads. Major factors influencing the design of these foundations include differential settlement, heave analysis and a fast track construction approach. Little Britain will provide 43000 sq.m. of space in two linked buildings which will bridge a new road joining London Wall to Newgate Street. The foundation contract is well advanced and the building is due for completion in the Summer of 1990.

Jan 1, 1989

By Richard Short

Shallow rainfall-induced landslides in residual and colluvial hillslopes and steep embankments are a common occurrence in many settings [1, 2, 3]. While occasionally posing a threat to property and life-safety, they more often present an ongoing maintenance problem and can lead to the initiation of larger failures. Typically, these slides consist of 2 to 4-foot thick translational movements of silty and clayey soils down slope through the reduction of strength from increases in pore water pressures. Direct surficial infiltration and indirect groundwater seepage are the normative triggers for failure. In the residential community of Blackhawk, California, located east of the San Francisco Bay, these types of landslides are a common occurrence (Figure 1). However, shallow landslides have also been a repetitive and constant problem along many state highways where steep embankments have been constructed in close proximity to busy thoroughfares. Given the real threat to property values in residential and commercial settings and the constant maintenance problem posed to lifeline structures such as utilities, roadways, and pipelines, new methods to deal with these landslides are needed.

Jan 1, 2007

By James G. Ulinski, Sebastian Lobo-Guerrero, Vishal B. Patel

"Recently modified design equations used in the transportation industry to calculate side friction and end bearing capacity for drilled shafts are now providing more realistic estimations of capacities than did previous methods. Using multiple case studies and test results from various projects, a more realistic design approach was formulated by the Federal Highway Administration (FHWA), which resulted in greater values of ultimate capacity for side friction and end bearing and in a more efficient design overall.In 2010, the FHWA published GEC-10 – Drilled Shafts: Construction Procedures and LRFD Design Methods, which illustrates a different method of calculating side friction and end bearing resistance and results in greater values for design. In 2014, the Association of State Highway and Transportation Officials (AASHTO) adopted the method put forth by FHWA, which was included in its LRFD Bridge Design th Specifications, 7 Edition. The Pennsylvania Department of Transportation (PennDOT) recently adopted and incorporated the similar methodology as AASHTO for calculating side friction and end bearing for drilled shafts in rock, and these changes are reflected in the 2015 edition of the PennDOT Design Manual, Part 4 (DM-4). This article discusses the past and current design methodology along with a project case study with results from Osterberg Cell (O-cell) load testing, which presents a comparison between the design resistances of ultimate side friction and end bearing and the measured capacities at failure.The Old and the NewEditions of the AASHTO LRFD Bridge Design Manual from 2012 and earlier estimated ultimate side resistance, qs, in rock using the following equation (modified from Horvath and Kenney, 1979):qs=0.65aEpa(qu/pa)0.5 < 7.8pa(f ’c/pa)0.5 where: qu is the uniaxial compressive strength of the rock in ksf; pa is the atmospheric pressure in ksf; aE is the reduction factor to account for jointing in rock; and f ’c is the compressive strength of the concrete in ksi. For intact rock, previous versions of the AASHTO manual required that the ultimate end bearing resistance, qp, was calculated using the following equation: qp=2.5qu."

Jan 1, 2017

By Maral Papazian Bedian

"Case 2. 100th Street Bus Depot: Elimination of Deep Caissons in Favor of Spread FootingsThe PROJECTThe 100th Street Bus Depot is a new five-story bus terminal for the New York City Metropolitan Transit Authority occupying one city block in Manhattan between 99th and 100th Streets, and between Lexington and Park Avenues. It replaces a former two-story garage, built in the 1890’s and initially used as a trolley-car barn. The new structure is a steelframed building with concrete floors and includes a partial basement near its middle. The easternmost column line with design loads of 10 MN (1,125 tons) is within 1.5 m of the underlying multi-tube Lexington Avenue subway system. To support the new columns along the subway line, the project bid plans had called for 1 m diameter and 17 m deep drilled shafts. The upper 14 m of each unit would have required 50 mm separation from the surrounding rock to prevent stress from being imposed on the roof and walls of the adjacent tunnel. The column loads were thus transferred to below the base of the tunnel and supported by 3 m long sockets in bedrock. The bid documents contained extensive test boring information, which revealed that the project site was underlain by massive Manhattan Mica Schist bedrock within just 3 m below street level. In fact, the Lexington Avenue two-level and multi-tube subway had been tunneled through this rock circa 1910, leaving an about 6 m thick solid roof over the upper-level subway. The NX rock core recovery values were near 100 %, with average RQD of 75 %.The CHANGEThe Bus Depot project was let as a design/build contract with a very aggressive fast-track schedule. Both the pre-bid preliminary design and the subsequent final design by the Contractor’s own hired design engineers relied heavily on very restrictive codes, including unnecessarily conservative approaches to seismic design. Any suggestion for value engineering change was undesirable and was strongly resisted. Yet, objecting against the blind reliance on codes in foundation design, the author questioned the real need for the deep drilled shafts to support the columns along the subway. The unsupported statement that no stresses from the new structure can be imposed on the roof and walls of the adjacent tunnel was not sufficient reason for the drilled-shaft design. Unconvinced that deep shafts were necessary, the author rushed to MTA’s warehouse where many rows of rock core boxes were neatly stacked. Careful inspection and some simple testing of the rock cores with the blows of a geologic hammer gave support to the reservations about the design. Later, as expected, the schist bedrock at this site was found to be hard to very hard with unconfined compressive strength values estimated to range from at least 70 MPa to over 100 MPa (10,000 psi to 15,000 psi). The tensile strength of the rock was assessed to be minimum 5 MPa (750 psi)."

Jan 1, 2003

By Paul J. Sabatini, Yazen A. Khasawneh

"A Demag CC1800 crawler crane was partially erected on crane mats adjacent to a seawall when settlements near a corner of the crane mat area were observed to be slightly larger than previously assessed. A ground improvement program including installation of dry soil cement mix (DSM) piers was implemented to improve soil bearing capacity. Due to near-surface obstructions, only 75 percent of the DSM piers were installed to the design depth. Because of the partial installation of the DSM piers, an evaluation of the crane pad stability and the effect of the crane loading on the stability of an adjacent 10-ft high concrete seawall, which was believed to have limited (if any) reserve capacity, was required. A two-dimensional finite element model was developed to evaluate the responses of the partially improved ground and the sea wall to the loads imposed by the crane. Geotechnical site investigation and laboratory testing programs were performed to better define the subsurface conditions near the area where settlements occurred and to provide the required mechanical parameters for the soil constitutive model. Analysis results indicate that total and differential settlements of the crane pad and the increase in load on the seawall were tolerable provided limited excavation and replacement of weak dredged soils outside the DSM area would be implemented.INTRODUCTION & BACKGROUNDA Demag CC1800 was erected on 8 ft × 16 ft crane lattice mats at about 12 ft from an existing seawall. Approximately 3.5 in. of subsidence was observed at one corner of the crane mats, while the crane was partially erected and stationary. The approximate location of the crane mats with respect to the existing seawall when the subsidence occurred is shown on Fig. 1.The seawall consists of a reinforced concrete wall connected by reinforced concrete bents to a composite section of sheet pile wall; the total depth of the seawall is about 29 ft. The bents are spaced at about 20’4” and supported by five piles at each bent location. The composite sheet pile consists of concrete and a sheet pile section with a reinforced concrete wale section. The retaining wall is about 10 ft in height and is supported at three levels. The first support level comprises a 2-½” diameter steel rod near the top of the wall spaced at 40’8” the second and third level supports comprise 1-½” diameter steel rods spaced at about 5’6”. The second level support is inclined at about 10 degrees below horizontal and the third level support is oriented horizontally through the wall footing. A schematic of the seawall section is shown on Fig. 2.A geotechnical site investigation was implemented soon after the subsidence was observed. The program included advancing four borings to a depth ranging from 16 ft below ground surface (bgs) to about 30 ft bgs. In general, the investigation showed sandy material (likely fill that was used behind the retaining wall) from the ground surface in two borings located immediately behind the retaining wall. The other two borings furthest from the retaining wall showed very soft to soft clay (possibly dredged material) from the ground surface to a depth of about 10 ft bgs. Based on this information, the ultimate bearing capacity of the subsoils was estimated to range from 1,200 to 2,000 pounds per square feet (psf). From the anticipated crane loading (weight of the crane and loading lifts), a minimum allowable bearing capacity of about 1,500 psf would be required for safe operation. To achieve the required bearing capacity a ground improvement program was selected and implemented."

Jan 1, 2017

By Hitoshi Ogura, Koichi Kobayashi, Sadao Yabuuchi

"In Japan, most pile foundations using pre-cast concrete piles are installed by the bored pre-cast piling method, wherein pre-cast piles are installed in holes that have been excavated beforehand and filled with cement milk (term used for cement water slurry in Japan). The bored pre-cast piling method with enlarged base, in which the portion near the toe is enlarged during boring operation, is widely used because of the cost benefits and the increased vertical bearing capacity that this method offers.The EX MEGATOP method, further developed as an improved bored pre-cast piling method with enlarged base, is reported here. The features of this method are: (1) High vertical bearing capacity; (2) High degree of freedom in design; (3) Excellent workability; and (4) Friendly to the environment. In particular, high vertical bearing capacity can be obtained using nodular piles and by enlarging the area at the pile toe and shaft. This method can gave a vertical bearing capacity coefficient at the toe of a=430, more than twice the corresponding value of a = 200 of a conventional bored pre-cast pile. Moreover, the shaft resistance can be several times larger than that of a conventional bored pre-cast pile. This report gives an overview of the EX MEGATOP method, evaluation of vertical bearing capacity, and examples of application of the method.1.lntroductionMost pile foundations in Japan are installed by the bored pre-cast piling method, that is, in holes that have been excavated beforehand and filled with cement water slurry, referred to as 'cement milk'. The ""bored pre-cast piling method with enlarged base"" is frequently used. In this method an enlarged excavation is used near the pile toe to increase the vertical bearing capacity.The EX MEGATOP method is a variation of the bored pre-cast piling method. Its features include the use of nodular piles and a long, enlarged excavation. The vertical bearing capacity of the EX MEGATOP method is described in this report."

Jan 1, 2005

By Muhannad T. Suleiman

Temperatures below freezing significantly enhance the soil shear strength and stiffness and to a lesser extent increase the compressive strength of concrete as well as the yield and ultimate strength of reinforcing steel. Consequently, the lateral load resistance of bridge columns supported by drilled shafts becomes dependent on seasonal weather conditions. To investigate the effects of seasonal freezing on the behavior of bridge columns supported by drilled shafts, large-scale field lateral load tests were conducted at 23°C (73.4°F) and -10°C (14°F) on two identical units at an field test site, which consisted of glacial till soil classified as low plastic clay. The bridge column-drilled shaft systems were subjected to cyclic lateral load with the maximum lateral column top displacements reaching approximately ±30 cm (±11.8 in.). The soil at the test site was characterized at different temperatures using unconfined compression tests in the laboratory as well as in-situ Cone Penetration and Pressuremeter Tests. Using these test results, the lateral load behavior of the column-drilled shaft systems were analyzed utilizing numerical models that consisted of beam elements representing the concrete column and the shaft and lateral springs representing nonlinear p-y response of soil. This paper focuses on comparing the calculated responses of test units with different p-y curves that were developed for the soil near the ground surface using the laboratory and in-situ tests. From the experimental study, the response of the unit tested at -10°C (14°F) was found to show 44% increase in lateral force resistance and 0.84 m (2.76 ft) upward shift of the maximum moment location compared to the response of the identical unit tested at 23°C (73.4°F). Theoretical behavior that included the temperature effects on soil, concrete and steel properties provided good correlation with the measured responses when the soil near the ground surface was modeled using the unconfined compression test or the Cone Penetration Test data, but not the Pressuremeter test data.

Jan 1, 2006

By Ed Revoort, Robert Schippers

In Rotterdam in the Netherlands the project ‘De Zalmhaven’ is being developed. The project consists of the realization of houses, parking facilities, two residential towers of 70 m and a residential high rise of 215 m. An artist impression for the project is given in figure 1. For the high rise a new development in the use of large diameter, drilled piles with a steel casing has been successfully utilized. In this article the installation method of 65 m long steel drilled piles in two consecutive sections is presented. The settlements for the building (and the influence on its surroundings) have been analyzed in detail using 3D Finite Element calculations, which will also be discussed. Finally there is focus on the results of settlement measurements carried out during construction in relation to the settlement prognosis.

May 1, 2022

By K. Rainer Massarsch

The effects of soil displacement caused by pile driving on adjacent piles and structures are discussed. A method is proposed to estimate the point of force equilibrium which makes it possible to calculate up-lift forces and pile head movements. For the case of pre-coring a method is proposed to estimate the stability of the bore hole, based on cavity expansion theory. Model tests were performed to establish the displacement pattern of the soil during the driving of a pile group. It can be concluded that at the ground surface, already installed piles have little influence on the lateral displacements, but reduce significantly the soil heave. During the driving of a pile group, the soil is displaced according to a complicated pattern, which is strongly influenced by the order in which the piles are driven. In clay the displaced soil volume corresponds to the total volume of driven piles.

Jan 1, 1989

By Benoit Virollet

Over the last 10 years the diameter of unbraced, unlined and unanchored circular shafts has grown dramatically in many parts of the world. This progress has taken place through improvements in: construction methods; concrete rheology; and design capabilities. Excavation equipment has become more precise in terms of operator control and ability to correct alignment of digging elements leading to better alignment tolerances. Also contributing to the increases in shaft diameters is the evolution of design models. A better understanding of soil structure interaction is being incorporated into the analyses in terms of radial soil stresses and imposed loads on the shaft. This paper provides an overview of the recent progress made in circular shaft construction, the primary design considerations, and some innovative uses of efficient arc elements to develop unsupported structures of other shapes. In addition, a summary of recent circular shafts constructed worldwide is provided.

Jan 1, 2006

By Kiyotaka Ohno, Nobushige Yasuoka, Yosuke Hioki

"The diameter of improved columns adopted by the original DJM Method had been 1000 mm, however, in order to comply with the social need for construction cost reduction, the Expanded Dry Jet Mixing (EX-DJM) Method with maximum column diameter expanded to 1300 mm was developed between 1998 and 2001 and has been widely applied since then. From the first application of EX-DJM in January 2002 for a first construction project, the total volume of improved soil has reached 325,000 m3 in 17 projects up to September 2014. Because of the advantages of the EX-DJM such as reduction of construction costs and periods leading to reduction in the number of improved columns, adoption of this method is expected to increase in the future. This paper describes the advantages of the EX-DJM, its construction results and case examples including those applied to restoration projects after the Great East Japan Earthquake, 2011.1. BACKGROUND OF DEVELOPMENTThe Dry Jet Mixing (DJM) Method is a soil stabilization method in which a powdery or granular binder is pneumatically fed into and mixed with soft soil to induce chemical reactions that stabilize and strengthen the soil. It was developed by government - private collaboration in Japan between 1977 and 1979. Up to March 2014, the total volume of soil improved by DJM method reached 33,500,000 m3. The initial diameter of improved columns of the original DJM Method was 1000 mm. In order to comply with the social need for construction cost reduction, the Expanded Dry Jet Mixing (EX-DJM) Method with maximum column diameter 1300 mm was developed between 1998 and 2001.2. ADVANTAGES OF EX-DJMThe construction equipment for the EX-DJM consists of two major parts, which are DJM machine and binder plant are shown in Fig. 1.The construction machine is of double mixing-shaft type with its column diameter expanded to 1200mm or 1300mm. In association with the increase in the column diameter, the binder feeder has also increased its discharge rate by approximately 1.69 times. Same as the increase rate of the area of original diameter 1000mm to diameter 1300mm are shown in Fig. 4."

Jan 1, 2015

By Rick Deschamps

"Fountain Slide is located approximately 10 mi (16 km) northeast of Lillooet, British Columbia, Canada, within the Coastal Mountain Range, and has been locally active since the 1970s. The project site is located near the base of the relic Tunnel Mountain landslide. The progressive movements have posed a significant challenge to British Columbia (BC) 99, the main north-south highway in the region. The slide began affecting the British Columbia Railway Company (BCR) tracks in the 1990s. In 2004, the Canadian National Railway Company (CN) acquired BCR and, during the next 11 years, undertook measures to stabilize the rail bed. Some of the measures undertaken include numerous track realignments, a shotcrete and soil nail wall, an anchored soldier pile-and-lagging wall, and adding a row of anchors to the wall. For many years, the measures had proved successful until mid-2014 when it was observed that the slide retrogressed uphill of the tracks. Since that time, the slide movements typically ranged between 5/32 and 0.4 in (4 and 10 mm) per day, leading to extreme distortion of the earth retention system and the need for frequent track realignment.In the spring of 2016, CN issued a request for proposals (RFP) for a designbuild solution with the expectations of: (1) a safety factor greater than 1.2, (2) considering only the currently identified retrogressive blocks that extend to about 200 ft (61 m) above the track; and (3) minimizing activities outside the current easement. It was also communicated that there was a possibility that a portion of the line may have to be abandoned if the proposed remediation was cost prohibitive.The fact that the existing slide was a small fraction of the relic slide was intimidating. The relic slide extended for approximately 1.0 mi (1.6 km) above the uppermost retrogressive block that was now affecting the rail line. Other areas of concern included:"

Jan 1, 2017

By Roger Frank

"Abstract After noting the importance of standardization for piles, the European system is described (execution, tests and design, etc.). Some important aspects of Eurocode 7 are outlined (like the role of pile load tests). Finally, the calculation methods in the recent French standard for the design of piles following Eurocode 7 are shortly addressed.Importance of standardization for piles Like for other fields of geotechnical engineering, pile engineering is a complex art. For piles, the challenges are particularly numerous and many things must be mastered properly: - the soil investigation must be serious and adequate (for instance, deep enough!);- the choice of the pile type and the assumed behaviour must be assessed in order to reach a safe and economic design of the overall foundation;- the execution itself (construction and/or installation) deserves special attention and must follow strict state-of-the art rules.The geotechnical engineer, in charge of the design of a pile foundation, must have in mind the parameters linked to the variety of soils, of soil conditions and of pile types. A wide range of strong environmental issues are also to be considered: minimum disturbance during the execution processes, long-duration friendliness of the “inclusions” into the ground (to avoid pollution of the soils and waters, for instance) and respect of the neighbouring structures.Pile engineering plays in a world which is constantly moving and progressing: constructions expand in new difficult areas, actions on piles are more and more important, new execution techniques of piles are developed, research into the complex behaviour of pile foundations has no end, etc. Our views on how piles and group of piles really work are constantly evolving!"

Jan 1, 2014

By Gordon King

The site of the First Quality Tissue plant is located on a previous paper production facility in Lock Haven, Pennsylvania. The new development, which included the construction of a tissue machine building, baled building, converting building, various storage buildings and an electrical switchgear building, required the use of deep foundation systems to transfer loads below compressible fill and alluvial soils. Loading details provided by Jacobs Engineering, the project structural engineer, detailed braced steel frame buildings with typical column loads ranging from 75 to 150 kips and slab live loads of 250 to 300 psf. As an exception to this, however, the tissue machine and stock preparation building, which had a roof height ranging up to 85 feet, had column loads ranging up to 800 kips in addition to high dynamic loads. The First Tissue plant is located in a river valley in the hills of Western Pennsylvania. To evaluate the proposed site conditions and to formulate recommendations for the structure foundations, a geotechnical study was performed by the owner. Approximately 30 borings were advanced to bedrock, with wire-line coring performed in the tissue machine building. The borings disclosed a soil profile comprising of the following:

Jan 1, 2004

By Christopher J. Ramsey, Don W. Dotson

"An existing four lane section of US 27 was widened to eight lanes. The project lies in the rugged Valley and Ridge Province of the Appalachian mountains starting at the Tennessee River in Chattanooga, Tennessee and extending 2.6 km north to Signal Mountain Boulevard. This terrain presented many challenges to accommodate the road widening in the narrow, rugged topography. Multiple tiered wall systems consisting of large tieback walls, post-tensioned reaction blocks, and gravity MSE walls for a total of approximately 30 retaining walls were required. The retaining walls served to stabilize the thrust faulted geology while also minimizing right-of-way acquisitions. The cut walls consist mainly of a tiered system of tied-back soldier piles walls with cast-in-place concrete facing. Cast-in-place pile shear walls were required along the toe of existing MSE walls to maintain stability during construction. This paper discusses the design methodology, which includes a hybrid (rather than traditional) earth pressure diagram intended to reduce life-cycle maintenance and long-term performance. Further this paper addresses wall construction, slope stability analysis, landslide mitigation alternatives, soldier pile wall design features, site challenges, monitoring and performance (to date) of the wall systems.INTRODUCTIONThis project involves the proposed widening of US Highway 27 (State Route 29) from the north end of the Tennessee River Bridge at Manufacturer’s Road to State Route 8 (Signal Mountain Road), approximately 2.64 km of roadway (Fig. 1). The project site is located adjacent to the Tennessee River on the north side of downtown Chattanooga, Tennessee in Hamilton County. The existing, limited access highway is to be widened from four lanes (two northbound and two southbound) to a minimum of eight lanes. Some portions of the alignment will expand to as much as ten lanes where northbound and southbound ramp acceleration/deceleration lanes coincide.In addition to the number and heights of cuts and fills involved, a major factor in determining an economical design for the alignment is the complicated geologic conditions along the roadway alignment. The existing roadway is situated between several steep cut slopes, some of which are only marginally stable or currently exhibit signs of instability. Due to the proximity of the project to the downtown area, the steep slopes along the alignment, and the relatively dense population near the alignment, widening the pavement and constructing cut and fill slopes to a stable configuration would result in major land acquisition for slope right-of-way."

Jan 1, 2015

By Robert B. Bittner

"AbstractLarge diameter tubular piles offer significant advantages in terms of design performance and economy for major marine structures. This is particularly true for foundations of major overwater bridges in regions of high seismicity such as the west coast of North America. The use of large diameter piles in the range of 2 to 3 m diameter means that fewer piles are required, and the size and mass of the pile caps can be significantly reduced, thereby greatly reducing lateral load demand during seismic events. Another advantage of using larger diameter piles is increased pile stiffness that allows the pile caps to be located at or near the waterline rather than being positioned at or below the mud line. This elevating of the pile cap offers significant cost savings by eliminating the need for deep cofferdams. However, relocation of the pile cap creates new problems and opportunities in regard to the means and methods used to construct the pile cap. With the pile cap at depth, conventional steel sheet pile cofferdams with thick tremie seals are typically used to isolated the cap location and allow dewatering for construction of the cap. However with pile caps positioned up off the bottom, conventional bottom founded cofferdams are no longer cost efficient. Float-in or lift-in cofferdams have been developed to address the need for a more cost efficient method for cap construction. This paper describes the key features of the concept and provides three case history examples of its successful implementation.Pier Construction Using Conventional Sheet-Pile CofferdamsCofferdams are temporary structures used in the construction of bridge piers and other marine structures. Their primary purpose is to hold out water and unstable soil from the construction area, and thereby, allow in-the-dry construction of the permanent structure below the water line and quite often below the mud line. Typically, cofferdams consist of long interlocking steel sheet piles driven through water into the bottom of the waterway. The sheet piles form temporary exterior walls which are typically braced internally with wales and struts. The bottom of the cofferdam is typically sealed with tremie concrete or an impervious clay layer if one exists. The depth at which this type of cofferdam can be used is typically limited by the length of steel sheet pile that can be transported and handled by conventional marine equipment."

Jan 1, 2014

By Chu E. Ho, Paul Napoli

This paper presents the performance of nineteen open-ended steel pipe piles driven through highly variable overburden soils into glacial till and schist bedrock. The piles were 16 inches in diameter and 0.656 inches thick, with yield strength of 50 ksi. The piles were designed for a service capacity of 250 kips and were driven to achieve an ultimate geotechnical capacity of at least 500 kips. Due to the large variation in the ground conditions, installed pile lengths ranged from 25 to 66 feet. Some piles were driven to refusal on the bedrock while others were terminated at final driving resistance of 2 to 7 blows/in. Two piles were suspected to be plugged during driving while others did not. Each pile was instrumented with strain gages and accelerometers near the pile top, and observed using a Pile Driving Analyzer (PDA) to provide preliminary guidance on pile capacity achieved at end of initial drive (EOID). The influence of plugged and unplugged pile toe conditions on the interpretation of pile capacity was investigated using Case Pile Wave Analysis Program (CAPWAP). Characteristics of driving energy, compressive and tensile stresses developed in the steel pipe piles, and the resulting pile deformation behavior are discussed. INTRODUCTION The Hunters Point South redevelopment in Long Island City, Queens is one of New York City’s major efforts to transform former manufacturing zones into mixed developments for the middle-income community. The site is located along the eastern shoreline of the East River and Newtown Creek. The development included low to high-rise residential buildings, a public school and retail structures. Open spaces were created 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 with the shoreline protected by revetments as part of the City’s flood mitigation strategy. The project was implemented in two phases, with completion of construction for Phase 1 in 2013 and Phase 2 in 2019. Based on available historical information, extensive reclamation took place between 1855 and 1898. After 1951, changes to the shoreline were made along the East River, including the removal of reclaimed land along the northern portion of the project site to allow for docking facilities. By 1977, these facilities had been demolished and backfilled to form the current shoreline configuration. The present site was temporarily used as a parking lot with stockpiles of fill mixed with construction demolition rubble, rip-rap and boulders of varying heights across the site. The existing ground surface varied significantly up to approximately 25 feet difference in elevation. The stockpiles were removed and the site was re-graded during final development of the project. This paper discusses the foundation design challenges due to the loose overburden soils and potential obstructions within the fill material, in particular, the issues relating to installation of open-ended steel pipe piles through the ground conditions encountered on site.

Jan 1, 2019

By Rüdiger Wunsch

The new high speed Vienna - St.Pölten line and the Lainzer tunnel are to be connected to the existing Western railway line in Vienna. This involves building an underground cut and cover branching tunnel which will be connected to the Western railway line by ramps. A key structure is the Herzmansky Street tunnel, which has a length of some 820m. It is to be constructed as a cut and cover tunnel using the top down method. The walls of the tunnel are designed as a water resistant structure consisting of double walls, an outer wall of bored piles and an inner reinforced concrete wall. The bored pile wall will be used as a temporary retaining wall during the construction phase and will also be a structural part of the per­manent tunnel wall. The retaining walls of the open pit, which will have a depth of up to 14m and a width of 12m, were investigated as a non-contiguous bored pile wall and overlapped bored pile wall. Preventing ground water from penetrating into the pit is of paramount importance. The high ground wa­ter level is the determining factor for the dimensioning of the bored pile wall and results in the require­ment for a water resistant concrete structure. It has been necessary to adopt adequate measures, therefore, in order to reduce the hydrostatic water pressure during the construction phase, assuming economical pile dimensions.

Jan 1, 2000