Search Documents

By S. L. Karunakaran

Selection of an appropriate foundation system requires great skill and ingenuity on the part of the designer. Certain guidelines for choosing between a pile and raft foundation are presented. A number of methods are available for estimating the capacity of piles, giving a wide range of values for the theoretical load carrying capacity. A few aspects to be taken into account while arriving at an appropriate theoretical capacity are discussed. The effect of fluctuation of water table level on the pile capacity and method of accounting for this factor on the pile capacity obtained through initial load test are also discussed. A case study presents a comparison between the estimated values of capacity of piles and the values obtained through the initial load test.

Jan 1, 1996

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 James M. Tantalla, Jr. Ellman

"Construction of the powerhouse for the Willow Island Hydroelectric Project, located at the Willow Island Lock and Dam, required a 120-ft deep temporary excavation inside the limits of a cellular cofferdam on the Ohio River side of the excavation and a soil-bentonite seepage cut-off wall on the landward side of the excavation. Stability analyses were performed for critical sections to evaluate the stability of the soil slopes and rock cuts using limit equilibrium, tension crack, and buckling analysis techniques. The stability analyses indicated adequate factors of safety through the landside embankment sections, and for the weighting berm soil slopes in front of the riverside cellular cofferdam. However, the results of deep-seated stability analyses through the rock supporting the riverside cellular cofferdam indicated marginal factors of safety for the 100-year flood condition. Consequently, the riverside portion of the excavation required enhanced stability measures, namely the installation of long, high-capacity rock anchors. Also, the dewatering system was modified to lower the site piezometric head to near the top of rock to improve the stability of the rock cuts.Thirty high-capacity rock anchors were installed on the upstream, riverside, and downstream sides of the cofferdam rock cut. The rock anchors consisted of multiple, seven-wire strands designed to provide the full-required design load at 60% of the strand capacity. Rock anchor loads varied from 1,968 to 2,074 kips. The maximum number of strands per anchor was 59. Bond lengths assumed an allowable bond stress of 100 psi based on the rock bond from pull-out tests.Project DescriptionAmerican Municipal Power, a nonprofit organization that owns and operates electric generation facilities for its member communities, has been in the process of constructing hydroelectric power plants adjacent to existing navigation locks and dams along the Ohio River. The Willow Island Hydroelectric Plant was recently completed on the West Virginia bank of the river adjacent to the US Army Corp of Engineers (USACE) Willow Island Lock and Dam. The plant is on the opposite river bank to the locks, and includes two turbine generating units with FERC rated capacity of 44MW at a 20-foot head differential. The Ruhlin Company of Sharon Center, Ohio was awarded contracts to construct both the cofferdam and the powerhouse. Construction began in mid-2011, and was completed in early 2016."

Jan 1, 2016

By Andrew Stauble

This project included the replacement of the Long Island Railroad (LIRR) Atlantic 6 Bridge in New York City, which services rail traffic and spans the Van Wyck Expressway and frontage roads. The bridge re- placement was part of an overall project to widen the Van Wyck Expressway between Kew Gardens and John F. Kennedy Airport, which serves as the major route for vehicular traffic between the airport and the city. The railroad bridge crosses the expressway and frontage roads in a significantly congested area, and it services an average of approximately 140,000 commuters per day through- out the boroughs of Manhattan, Brooklyn and Queens. The existing bridge superstructure and foundations were to be demolished and new structures and foundations were proposed to be constructed at the bridge's east and west abutments and center pier. The new bridge would be supported on driven H-piles. To facilitate the construction of the new bridge's abutments and center pier, a support of excavation design was required to support the grade around the existing structures. The design shown on the contract drawings included a driven soldier pile and lagging wall with multiple rows of drilled tiebacks at the abutments to laterally support excavation heights of up to 36 ft (11 m). The existing abutments are located directly adja- cent to frontage roads that have an extremely high vehicle traffic volume,

Aug 1, 2023

By José L. M. Clemente, John R. Davie

"Abstract An extensive pre-production static and dynamic pile load testing program was conducted for a coal-fired power plant. The static load testing program included axial compression, uplift (tension), and lateral load tests. Three types of piles were tested: Monotube, closed-end pipe, and step-tapered. The load tests were used to (a) determine pile driveability characteristics for each pile, (b) verify pile load response behavior, and (c) provide data to support the selection of a cost-effective piled-foundation system for the plant. A recent publication (Clemente and Lewis, 2013) describes the compression load testing program, the interpretation of instrumentation measurement results, and pile selection criteria. This manuscript describes site subsurface and groundwater conditions and installation of probe piles for testing, focuses on the uplift and lateral load testing program, and provides a comparative interpretation of the load test results.INTRODUCTIONThe pre-production probe pile load testing program described here was conducted for a 202-megawatt, coal-fired power and steam generating (cogeneration) facility. A schematic layout of the main plant (power block area) is shown in Figure 1, which also includes the locations of clusters of preproduction probe piles and boreholes drilled near these clusters.The load testing program included 24 pre-production probe piles driven throughout the power block area. The probe piles were driven at locations T-1 through T-8, shown in Figure 1. Three types of piles were driven at each location: Monotube pile; closed end, straight shaft pipe pile; and step-tapered pile. At each location, the three piles were driven in a row with the pipe pile at the center, and the center-tocenter spacing between piles was equal to about 1.5 m (> 3.5 pile diameters for the largest pile). No pile cap was used to connect the three piles, and the three piles driven at locations T-1 through T-8 will be referred to as pile clusters. A complete suite of static load testing (compression, tension, and lateral) was performed on each individual pile at Cluster T-2 and on the step-tapered piles only at Cluster T-8, shown in Figure 1.Clemente and Lewis (2013) provide details of the compression load testing program, the interpretation of instrumentation measurement results, and pile selection criteria. This manuscript focuses on the uplift (tension) and lateral load testing program. A brief summary of the site geology and existing subsurface and groundwater conditions in the vicinity of the test pile clusters is presented, with emphasis on T-2 and T-8. Probe pile driving results at T-2 and T-8 are also presented. Descriptions of the static uplift and lateral load test program at T-2 and T-8 are given along with a comparative evaluation of the load test results."

Jan 1, 2014

By Jr NeSmith

"Drilled Displacement piles are a product of screw pile technology originally developed in Europe. The process involves rotating tool into the ground that displaces the soil laterally as it advances, then grouting or concreting through the hollow stem of the tool as it is withdrawn. They were first introduced in the United States in the 1990’s and have become a mature and accepted technology since that time. They are now used to support a variety of heavily loaded structures including electric power and LNG facilities, stadiums and arenas, airports and mid- to high-rise commercial and residential facilities. In urban environments, the technique has a number of advantages including, low noise and vibrations, no removal of the existing soil, and reduced pile material cost due to the improved stress state of granular soils after installation (smaller or shorter piles can be used). For these reasons, displacement piles have been used to support various facilities in Northeastern United States (US). The paper presents case histories of the performance of displacement piles in the Northeastern US including the use of full displacement elements as a settlement limiting ground improvement system.INTRODUCTION“Drilled Displacement” (DD) is an industry umbrella term for a number of proprietary or commercially available cast-in-place pile installation systems which involve a hollow-stem tool that laterally displaces soil as it advances and the placement of grout or concrete through the hollow-stem tool as it is withdrawn. The systems include grout/concrete placement methods by both sand-cement grout pumped under pressure and tremie grout/concrete placement through bottom-hole discharge. The system discussed in this paper includes grout pumped under pressure, also referred to as Auger Pressure Grouted Displacement (APGD). A schematic of the APGD tool is shown in Figure 1. The tools require significant torque and downward force to advance; a typical installation platform is shown in Figure 2."

Jan 1, 2016

By Geoffrey Birch

A skilled and efficient workforce is a pre-requisite for the success of modern construction companies. The drive for improved performance, innovation and best value must be matched by the enhanced skills of the construction personnel. Training has been accepted as one of the essential cost effective elements to achieve these goals. The foundation industry demands particular specialist skills and requires focused training for its dedicated operatives. The introduction and development of specific training qualifications for the foundation sector is providing significant benefits.

Jan 1, 2000

By Roy Jennings

The Discovery Expedition of St. Charles, MO chose to build its two-story museum in the flood plain of the Missouri River, near the starting point of the Lewis and Clark Expedition. Should the lower level be inundated at flood stage, plans call for the replica riverboats to be moved by trailer to higher ground. The museum&apos;s design required an open span structure with heavily loaded footing or piles. Spread footings could not be used due to the compressible soil profile. The location, in a historical district, precluded dynamically driven piles. Sixty-three uncased Helical Pulldown Micropiles were driven to the bearing stratum to support the museum with minimum disturbance. There were no spoils to dispose of during construction and the piles were completed in eight working days with minimum impact to the environment and neighborhood. The maximum working load required was 84,000 pounds (374kN). Test results are given in the form of installing torque.

Jan 1, 2003

By Karl A. Higgins

In 1976, Prof. G. G. Meyerhof published a famous article in the Journal of Geotechnical Engineering titled ?Bearing Capacity and Settlement of Pile Foundations?. This article presents the authors opinions on calculating pile capacities in clays and sands, group capacities and pile settlement. A portion of the article presents correlations of shaft friction and end bearing to the Standard Penetration Test (SPT) N-value. Subsurface exploration via the Standard Penetration Test is the most widely used exploration tool in the United States, so correlations of pile capacity to N-value are significant to the practice of geotechnical engineering. Meyerhof?s SPT-N correlations are relatively simple calculations compared to other pile capacity computation methods presented in the article or found in other text books (such as the a-method, b-method, Nordlund, Vesic, Meyerhof?s semi-empirical, others) and therefore are popular amongst practicing geotechnical engineers. At the time these correlations were published by Prof. Meyerhof, utilization of dynamic testing with the Pile Driving Analyzer (PDA) was not widespread in geotechnical engineering practice. Prof. Meyerhof?s correlations appear to be based upon conventional static pile load testing of instrumented piles. Dynamic pile measurements to estimate a pile?s static capacity provides certain advantages over conventional static load testing, namely the determination of unit shaft friction values at discrete intervals along the pile, and the unit end bearing support value. The author has compiled a database of driven, displacement piles tested with dynamic methods (ref. ASTM D4945, Test Method for High-Strain Dynamic Testing of Piles). The data was collected between 2002-2010 and is comprised of displacement piles driven into coastal plain sediments in the mid-Atlantic states of Virginia, Maryland and the District of Columbia. In layered soils, dynamic testing in particularly helpful as it reveals the differences in unit shaft friction for varying soil types. One hundred ninety (190) piles are included in the database, with a corresponding 1,373 discrete shaft friction and 190 end (toe) bearing measurements. The pile type typically consisted of 12 and 14 inch square, prestressed, precast concrete piles; however, a significant number of piles were steel HP 12 or 14 inch sections. The database was sorted based upon soil type, and then correlations of shaft friction and end bearing were derived in the same or similar manner as Meyerhof?s original 1976 publication. The new correlations are compared to Meyerhof?s original values.

Jan 1, 2011

By Madhu. P, Srinivas. K

Measurement of thermal properties like thermal conductivity, thermal resistivity, heat capacity and thermal diffusivity for materials, it plays a crucial role in a wide range of various civil and electrical engineering projects, and many field applications like building’s basement, power generation, underneath soil heating, wastes from nuclear as well as thermal plants, and buried cables. Thermal conductivity of soil depends upon various geotechnical parameters such as type of soil, moisture content, particle size distribution, density, and compaction characteristics. Earlier studies, the measurement of thermal conductivity of soil by incorporating the heat source methods. Thereby expensive and time taken to conduct in laboratory as well as field measurements. The thermal conductivity is determined by fabricated probe and used in this work. Fabricated probe was calibrated with glycerin. The thermal conductivity of the soil increases as the water content and density increase because these factors are majorly influencing and water has a higher thermal conductivity than soil minerals, and grain to grain contact increases as density increases. therefore, Thermal conductivity is higher in coarser soils than in finer soils. The details regarding of this work as explained in this paper.

Sep 1, 2022

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

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

Jan 1, 2015

By Klaus Pöllath

The Netherlands RandstadRail project makes use of a large range of sophisticated geotechnical techniques to allow a shield driven tunnel to approach the central station of Rotterdam. This paper describes the construction of three deep excavation pits constructed with 1.2 m and 1.5 m thick diaphragm walls. Besides the presentation of the actual diaphragm wall activities special consideration is given to the break-in and break-out situations of the TBM into the deep excavations pits using sealing blocks and partly glass fibre reinforcement in the diaphragm walls.

Jan 1, 2006

By Lin Li

A reliability based analysis method for a drilled shaft stabilized slope system is presented in this paper. In the past effort, a deterministic method using the limiting equilibrium method of slices for determining the global factor of safety of a slope reinforced by a row of drilled shafts was developed using the soil arching concept. The drilled shaft stabilization mechanisms for the slope were treated as the drilled shaft induced soil arching, which reduces the driving forces on the down slope side of the drilled shaft. The effect of drilled shafts induced soil arching on the reduction of the driving stresses in the limiting equilibrium slope stability analysis was quantified by the load transfer factor through extensive finite element simulation studies. A semi-empirical equation was also developed for expressing the load transfer factor as a function of the soil properties, including strength parameters and unit weight as well as the slope geometry and soil profile, the location and spacing of the drilled shaft, and the dimension of the drilled shaft. However, due to the inherent uncertainties of the soil properties and the model error of the semi-empirical load transfer equation, a modification of the deterministic method into a probabilistic method is developed in this paper. The Monte Carlo statistical method is used to generate random variables for the soil strength parameters based on the prescribed probability characteristics, including mean, COV, and the probability distribution function. In addition, the modeling error of the load transfer factor is also treated as a random variable in the Monte Carlo simulation method, in which the mean, COV, and probability distribution function for the bias of the semi-empirical equation are used. The developed theories were coded into a computer program for analyzing complex slope geometry and slope profile conditions. Two examples are shown in the paper to illustrate the analysis results of the developed probability approach for determining the reliability of a drilled shaft stabilized slope system.

By Lin Li

A reliability based analysis method for a drilled shaft stabilized slope system is presented in this paper. In the past effort, a deterministic method using the limiting equilibrium method of slices for determining the global factor of safety of a slope reinforced by a row of drilled shafts was developed using the soil arching concept. The drilled shaft stabilization mechanisms for the slope were treated as the drilled shaft induced soil arching, which reduces the driving forces on the down slope side of the drilled shaft. The effect of drilled shafts induced soil arching on the reduction of the driving stresses in the limiting equilibrium slope stability analysis was quantified by the load transfer factor through extensive finite element simulation studies. A semi-empirical equation was also developed for expressing the load transfer factor as a function of the soil properties, including strength parameters and unit weight as well as the slope geometry and soil profile, the location and spacing of the drilled shaft, and the dimension of the drilled shaft. However, due to the inherent uncertainties of the soil properties and the model error of the semi-empirical load transfer equation, a modification of the deterministic method into a probabilistic method is developed in this paper. The Monte Carlo statistical method is used to generate random variables for the soil strength parameters based on the prescribed probability characteristics, including mean, COV, and the probability distribution function. In addition, the modeling error of the load transfer factor is also treated as a random variable in the Monte Carlo simulation method, in which the mean, COV, and probability distribution function for the bias of the semi-empirical equation are used. The developed theories were coded into a computer program for analyzing complex slope geometry and slope profile conditions. Two examples are shown in the paper to illustrate the analysis results of the developed probability approach for determining the reliability of a drilled shaft stabilized slope system.

Jan 1, 2017

By David J. White

The decreasing availability of land in urban areas, and the increasing demand for urban development is leading to the construction of taller and heavier buildings at increasingly marginal sites. Such structures usually require founding at depth and modern construction methods are making the economics of piled foundations ever more attractive (Salgado, 1995). However, the urban environment is not suited to pile driving. Conventional dynamic installation techniques (i.e. drop hammer or vibro-piling) induce vibrations and settlement in a zone close to the pile, and cause noise and dust pollution. Damage to existing structures resulting from pile driving vibrations is not uncommon (Tomlinson, 1986).

Jan 1, 2000

By Hitendrabhai S. Dewangan, Dr. Aashish A. Mehta

Pile foundation is widely used in construction of marine structures. In offshore & marine piling work, drilling/boring supporting fluid is used to stabilize the borehole (excavation) prior to tremie concrete. The poly-fluid is a synthetic drilling granular polymer characterized by high molecular weight.it is mainly used for the preparation of stabilizing and lubrication mud in drilling of deep foundations. Disposal of polymers after using it into the sea, pollutant the sea environment, which may be harmful for living organisms inside sea. To reduce the pollution in offshore/Onshore, it is essential to take the precautions during flushing operation with proper recycled, reused & it’s Disposal. To provide economic and environmental solutions, used slurry was treated with addition dose of fresh material/polymers. The amount of fresh materials/ Polymer to be added can be decided based on (viscosity, density and pH value) test results. Finally, initiate water flow and air agitation as required. Run the tests on the re generated slurry before transferring to storage tank. Also, after storage, polymers will be reused for next operation. Moreover, mud wastage coming from borehole will also be disposed at suitable dumping places.

Sep 1, 2022

By Clyde N. Baker

Foundations for the Sohio Corporate Headquarters in downtown Cleveland have column loads of 11,400 kips, which increase to 15,000 kips with wind loading. An extensive exploratory program was conducted and comprehensive studies made to select the economically dependable support for the 46-story structure. A test on bond or socket friction for the caissons has usable values.

Jan 1, 1984

By David E. Thompson

This paper describes the full-scale field load testing of three deep foundation units using the Osterberg Load Cell. The load tests were completed on three separate projects, two in Massachusetts and one in New York. The Massachusetts projects involved the load testing of two 18-inch O.D. concrete-filled steel pipe piles over water for railroad bridge reconstruction projects in Revere and Saugus/Lynn. The New York project involved the load testing of a 24-inch diameter drilled shaft socketed into sandstone on land for a building foundation in Rochester. The 18-inch O.D. piles were loaded to failure at jack pressures of 142 to 215 tons. The drilled shaft was loaded to failure at jack pressures of approximately 450 tons. The loading testing procedure is described and the results of the three tests are presented. The advantages and disadvantages of the Osterberg load cell for load testing of deep foundations are discussed.

Jan 1, 1989

By Jørn H. Thomsen

This paper presents the experience gained and the lessons learned over the last decade within the numerous offshore foundation projects undertaken in the offshore waters of Denmark and Belgium by COWI A/S of Denmark. This experience derives from the close collaboration with, and interaction between the owners, contractors, and engineers in the various stages of project development. In turn, the experience draws on COWI&apos;s experience within foundation of large bridges world wide over half a century. Focus is on two pioneering gravity base foundation projects: ? Nysted in Denmark, currently the largest offshore windfarm worldwide with 72 Nos Bonus 2.3 MW turbines in water depths up to 10 m in the relatively benign inner Danish waters ? Thornton Bank in Belgium, where the first phase - comprising 6 Nos REpower 5MW-turbines of a total of 60 - are planned to be built in the rough North Sea in water depths exceeding 25 m.

Jan 1, 2013

By Arturo Ressi di Cervia

From the times when men in lacustrine environments drove wooden piles into the mud to elevate their dwellings, until the beginning of the twentieth century builders reacted to the conditions found in the location of their proposed structures by attempting to distribute their loads in ways that could be supported by the foundation&apos;s soils; or, if those were unsuitable, by moving the structure, whenever possible. While many major structures were built on stable ground (the pyramids were founded on rock), others were built on [ ]

Jan 1, 2000