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By Peter O. Wilkinson

Ascot Racecourse in the UK is a major international venue for horseracing. The racecourse is being redeveloped to provide entirely new public facilities. The development includes the construction of a new grandstand. A site investigation was earned out comprising mainly cone penetration testing. The site is underlain by the Bagshot Formation, comprising predominately cohesionless deposits of medium dense becoming dense, silty fine to medium sand, containing occasional layers of clay. Shallow foundations would present uncertainty regarding total and differential movement; hence a piled foundation solution was chosen using a continuous flight auger (CFA) piling system. The possibility that piles may found either directly on or within the influence of cohesive material suggested uncertainty regarding toe resistance. In order to measure shaft friction, an instrumented preliminary test pile was undertaken. The results were compared to published correlations of cone and shaft resistance. This approach resulted in a net saving in terms of pile length which resulted in optimum value engineering and hence a cost saving to the client.

Jan 1, 2006

By Arash Saeidi-Rashk-Olia, Dunja Peric

Energy piles are gaining increased popularity due to a growing demand for clean energy. To further advance the understanding of soil-structure interaction in energy piles, recently-derived analytical solutions have been implemented to investigate the impact of stratigraphy on the soil-structure interaction. This was accomplished by comparing the measured and predicted head displacements, axial strains and stresses in an energy pile embedded in the actual homogeneous and layered soil profiles, as well as into synthetic homogeneous soil profiles. The analytical solutions for homogeneous soil profile captured the smooth experimentally observed response versus depth very well. In the case of a layered soil profile, the corresponding analytical model was capable of capturing nuances in trends of axial stress and strain versus depth at the interface of different layers. The analytical predictions for the layered profile appear to be slightly less accurate than for the homogenous profile. The experimental data obtained from the layered profile appear to be a bit more scattered than those from the homogeneous profile. In the former case, the interplay of the individual soil layers with the pile occurs while maintaining the continuity of the pile stress and displacement at the interface of different layers. The response throughout each layer of the layered profile is quantitatively different than the corresponding homogeneous response. Nevertheless, qualitatively the response throughout each layer of the layered profile is similar to the response of the pile embedded in the corresponding homogeneous layer.

Sep 8, 2021

By Wei Zheng

A pulverized coal fired power plant is being built in Osceola, Arkansas, along the Mississippi River. The subsurface soil conditions consist of a certain amount of very soft clayey silt and clay underlain with a medium dense sand layer and a dense sand layer. The site has been raised four to five feet with fill material consisting of sand and gravel. Consolidation settlement due to the fill is expected to cause negative shaft resistance (downdrag) on the pile foundations. The site is located in a high seismic hazard area - the New Madrid Seismic Zone (NMSZ). The liquefaction analyses indicated that there is a high liquefaction potential in the medium dense sand layer. Load tests are needed to determine the shaft resistance and the end bearing of each soil layer for design purpose. Two types of pile foundations ? augered pressure grouted displacement pile (APGD) and partial augered pressure grouted displacement pile (P-APGD) were considered for this project. Ten pile load tests, including five compression tests and five tension tests, were performed for three different areas. Strain gauges were installed for the compression tests. The APGD and P-APGD piles were installed side by side for comparison. In addition, three additional dynamic tests were performed to supplement the information from the static load tests. Load deflection curves for the compression tests were predicted, and the failure loads were interpreted using four different methods. The shaft resistance and the end bearing were determined from the strain gauge data and were used to back calculate the ultimate capacity. The back-calculated capacities are in good agreement with the predicted failure loads; they were further verified with the tension load test results.

Jan 1, 2007

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 Marwa Nabil, Alaa A. Ata

"Recent developments in the analysis of piled rafts has incorporated the load sharing of the raft and the piles to support the superstructure. In the piled-raft system, piles are cast monolithically with the raft and the load is partly transmitted by the raft to the soil directly below it, and partly by the piles to more competent deep soil. While these piles are effective in increasing the bearing capacity and reducing the settlements, they often lead to significant straining actions at the pile head-raft connection which may constitute the weakest link. An attempt to provide a more economical solution, that at the same time overcomes this weak link, is to disconnect the pile heads from the raft and introduce an intermediate cushion of compacted fill. In this case, the piles are considered as reinforcement to the subsoil and will also act as settlement reducers. This paper investigates the load transfers mechanism of the unconnected piled raft with cushion using ABAQUS finite elements Program. The main objective is to provide an in depth analysis of the raft–soil–pile interactions in multi-layered soil under static and seismic loads. The investigated system provides an economical alternative for traditional connected piled raft foundation, where there is no need to reinforce the piles, no need for pile head demolition or expensive waterproofing of the pile head connection. Cost analyses of unconnected versus connected piled raft systems confirmed a cost savings in the construction that may reach from 50 to 70 percent.INTRODUCTIONDesigners around the world have gained more confidence to use the piled-raft as a more realistic system where the raft and the piles share transferring the superstructure loads to shallow and deep soil layers. A further advancement is to use unconnected piled rafts as another practical and economical alternative to the traditional piled rafts. Unconnected piled raft is also synonymous to settlement reducing piles; or simply, soil improvement piles. Liang et al. (2003) has extended the concept of pile-raft-foundation to a new type of foundation called composite piled raft foundation or unconnected piled raft foundation. The foundation is composed of a sand/gravel cushion sandwiched between the raft and piles. The piles group may contain short and long piles. The short piles are constructed of flexible materials such as soil-cement columns or sand-gravel columns, and are used mainly to improve the bearing capacity of shallow soft soil; the long piles, which are made of relatively rigid materials such as concrete, and their main function is to reduce settlements. The cushion plays an important role in mobilizing the bearing capacity of the subsoil and in modifying the load transfer mechanism of the piles. In Shanghai, China, this system of unconnected piled raft has proved to be quite suitable and effective in coastal areas, where deep soft soil deposits exist."

Jan 1, 2016

By Kenneth E. Henn, David B. Paul, John D. Rice, Brian H. Greene

"Several laboratory modeling programs have been conducted to investigate the mechanisms associated with internal erosion of dam embankments and foundations. The investigation consists of developing laboratory devices to model three separate mechanisms associated with process: 1) contact erosion along bedrock joints, and 2) piping into an open bedrock defect. The contact erosion device subjects the soil above a bedrock joint to high velocity flows in the joint. The erosion into a bedrock defect device examines a number of static and transient hydraulic conditions to study the mechanisms associated with this type of erosion. Numerous tests have been conducted using both devices. The results of the modeling will be discussed along with a discussion of how this information could be used in future dam design and risk assessment studies.IntroductionA series of laboratory modeling programs were performed to assess the seepage and internal erosion behavior of several man-made and natural structures within dams and their foundations. Each model was performed on a “bench scale” and depicted an isolated location where internal erosion was likely to occur. The models were subjected to hydraulic boundary conditions to simulate the in-situ conditions so that the processes of internal erosion could be observed. Two laboratory devices were developed to model conditions depicting 1) contact erosion along a bedrock joint in contact with a dam embankment, and 2) backward erosion (piping) into an open bedrock defect (joint, solution void, etc.).Embankment dams often have rock foundations containing defects which may detrimentally impact future performance. Further, there are existing foundations which contain rock defects that may already be detrimentally impacting the dams; however, due to the inherent aspects of the mechanism, the signs of distress may not have propagated to the surface and thus not observed during inspections. A better understanding of the mechanisms which are influenced by, and impose their influence upon, rock defects will enhance the ability of dam safety professionals to analyze the risks associated with internal erosion due to rock defects, increase our ability to monitor and successfully initiate earlier detection, and also increase our ability to design remediation methods to contend with rock defect failure modes."

Jan 1, 2016

By Jean-Louis Briaud

The following is a summary of a very recent report prepared at Texas A&M University for the National Cooperative Highway Research Program and entitled "Downdrag on Bitumen Coated Piles". Anytime the soil settles more than the pile, downdrag or negative skin friction will develop. The load in the pile increases with depth up to a certain point and then decreases down to the pile point. This phenomenon has been quoted as being the number one culprit for deep foundation failures. In Chapter 1, an introduction to downdrag is given. The most common criterion for downdrag is to consider it in design as soon as the settlement of the soil surface after pile driving exceeds 0.5 in. Coating piles with bitumen is an effective way of reducing downdrag forces and therefore allows to use smaller piles for the same load. This results in cost savings. Coating piles with bitumen increase the cost of piles by about 33% and therefore the decision to use bitumen is generally based on economic considerations.

Jan 1, 1989

By David A. Staab

Numerical modeling was used to investigate the feasibility of using two geophysical imaging techniques, cross-borehole ground penetrating radar (XBGPR) tomography and electrical resistivity (ER) tomography, for detecting and characterizing defects in deep-mixed soil columns. XBGPR modeling was accomplished with a three-dimensional numerical forward modeling code and a two-dimensional inversion routine. Spatial variations in apparent dielectric constant (Ka) and attenuation (a) were mapped. Electrical resistivity modeling was accomplished with a three-dimensional numerical forward modeling code and a three-dimensional inversion routine. Spatial changes in electrical resistivity were then mapped. Three different types of defects were simulated, in addition to a defect-free column. The computer simulations suggest that XBGPR tomography and ER tomography might be useful, non-destructive methods for detecting and estimating the extent of defects in deep-mixed soil columns. The results show that small, isolated defects might be difficult to detect, but defects approximately equal to or larger than the sampling interval (for XBGPR) or vertical electrode spacing (for ERT) should be detectable.

Jan 1, 2004

By R. J. Yan

There was a plant equipped with a 32000t Hydraulic Press to be built, under which a box foundation of 22.5m x 15m x 14.25m (depth) with a base slab of, varying thickness was proposed. The subgrade reactions, bending moments and settlements needed to be determined by means of in-situ model test. A model of the same materials as the prototype scaled to l/10 was embedded in-situ with simulated depth in the bedrock. A lot of data obtained from 39 bench marks, 32 elongation measuring points, 30 couples of electric resistance strain gauges and 24 pressure cells attached to the model foundation enables all the quantities required to be found out. Since it was put into operation, the settlements measured has reasonably agreed with the test results and the foundation has been in good condition.

Jan 1, 2010

By Noreen Tarac, Pablo Forgoso, Philipp Schober

A multiple use storage facility building is being developed in the Philippines on a peninsula that was reclaimed in the 1990s without any soil treatment. The subsoil now consists of loose to medium dense silty sand underlain by a soft to medium stiff clay. A liquefaction assessment by analytical methods have shown that the loose to medium dense silty sand yields a high potential for liquefaction and lateral spreading during pthe design level seismic event. To mitigate the risk of liquefaction and lateral spreading, as well as assure the slope stability of the shoreline, a solution utilizing a combination of ground improvement techniques by means of a Mixed-In-Place (MIPTM) Lattice Grid Wall and Stone Columns was developed and successfully executed. For the detailed seismic design, a Finite Element 3D analysis was undertaken to simulate static and dynamic actions on the buttress wall. The liquefaction assessment and settlement calculation were carried out based on analytical design approaches. For the execution of the Lattice Grid Wall, the Mixed-In-Place (MIPTM) method developed by BAUER Spezialtiefbau GmbH was applied. The stone columns were installed using the Wet Top Feed method.

Sep 8, 2021

By Vasileios A. Drosos

The response of pile foundations to lateral loads is an important factor for the successful performance of several critical structures. A new numerical code for the analysis of single piles under lateral load is outlined. The code can simulate (through appropriately chosen parameter values) not only the non-linear behavior of soil, but also the inelastic structural response of the pile itself under lateral load. Emphasis is given on the calibration of model parameters and the verification of the code. For the calibration of the parameters, data is used (a) from the well documented in the literature p-y curves, and (b) from experiments conducted either in full scale or in the centrifuge. Results are compared to those of well known published codes for inelastic analysis of single piles under lateral load.

Jan 1, 2006

By Nadir Ansari, Brian W. Wilson, Marina S. W. Li

"A hybrid Deep Mixing (DM) shoring system was recently constructed for a high-rise development in downtown Vancouver, British Columbia, Canada for the temporary support of a five-level basement excavation. The site is bounded by an existing bridge off-ramp structure along its longest side and by city streets on the other two sides, which formed a truncated triangle in plan. A conventional secant pile wall was installed along the longest side, about 380 ft (116 m) in length, of the site. Hybrid shoring walls (HSW) 1 and 2 were installed along two shorter sides with each being 235 to 246 ft (72 to 75 m) long. HSW 3 completed the excavation support system along the shortest side with a length of about 55 ft (17 m). Cutter soil mixing (CSM) was proposed by the excavation and shoring design-build team in lieu of conventional secant piling. CSM was the preferred method to construct the infill panels between soldier piles because of the speed at which the shoring system could be constructed in the variable fill, peat, wood waste and overburden. Design ConsiderationsTo minimize the impact on buried utilities along the outside perimeter of the excavation, the temporary shoring was designed to limit the lateral displacements to less than 0.8 in (20 mm). Factors taken into consideration for shoring design included the lateral earth pressures from the fill and native soils, groundwater pressures, temporary construction loads (e.g., crane or heavy plant/equipment), and permanent structural requirements. The subsurface conditions at this site typically consisted of fill (cohesive and granular), overlying peat and/or wood waste, overlying clayey silt to sandy silt, overlying weathered to dense to very dense clayey silt till to sandy silt till with silt layers. Localized, perched groundwater was observed within the fill, peat, wood waste and sandy silt layers above the dense till."

Jan 1, 2017

By Jianhua Wang, Jianming Yao, Zhen Meng, Jinjian Chen

"Drilled screw pile is a newly developed displacement pile foundation which has been applied in soft clay for many years. Compared with traditional circular displacement pile, It is characterized by high bearing capacity, small volume and small squeezing effects. For the purpose of investigating the squeezing effects of drilled screw pile, a full scale field monitoring test with two test piles was performed. Detailed soil horizontal displacement and pore pressure measurements were conducted in the vicinity of the two drilled screw piles during penetration and subsequent soil consolidation. It can be concluded that the horizontal displacement of the surrounding soil induced by the installation of a drilled screw pile is mainly in a circular region with a diameter of 3 m (r/D<6), and the compaction effect outside the area can be essentially negligible; The excess pore pressures measured at the same time increase with depth throughout the entire process of consolidation, and its dissipation shows an exponential decay as a function of time.INTRODUCTIONA knowledge of the displacement and stress changes induced in the soil surrounding a pile is very important for evaluating pile performance. Numerous field and laboratory research projects have examined loading conditions, total soil stresses, and excess pore pressures during and following pile installation (Pestana et al., 2002). A relatively comprehensive and detailed review of these experimental works from 1948 to 2002 was presented by Pestana et al. (2002). More recently, Xu et al. (2006) conducted a field experiment to study displacements and stresses in the vicinity of two pipe piles during their installation in a soft lightly overconsolidated clay and compared the field measurements with existing predictive methods. Abdrabbo and Gaaver (2011) collected field observation data from four different construction sites to study soil disturbance during construction of piles using continuous flight auger (CFA). They have found that the disturbed zone of soil by CFA has a conical shape and the excess pore pressure has no appreciable influence on the load capacity of the piles.Drilled screw pile (DS pile) is a kind of vibration-free, cast-in-place concrete pile. Because of the excellent bearing performance, low level of vibration pollution and negligible spoil, as well as its fast construction speed, DS pile has been widely accepted by many engineers around the world. As a new type of drilled displacement pile, the significant installation effects of DS pile on the adjacent soil have not been systematically and integrally investigated yet. Since a proper numerical simulation of the real installation process of DS pile is difficult to achieve, the investigation based on field measurements is necessary. This paper presents a field investigation of the installation effects of two DS piles on surrounding soils. Detailed horizontal soil displacement and pore pressure measurements during pile installation and subsequent soil consolidation have been conducted. Based on the monitoring data, variation of horizontal displacements and dissipation of excess pore pressures with depth and time have been analyzed. What's more, the construction machinery and technology used in DS pile installation are also simply introduced."

Jan 1, 2015

By Richard J. Hartman

This presentation identifies some of the more common problems associated with cofferdam construction. After the various problems are identified, they are briefly explained and possible solutions and preventive measures are noted. Photographic slides used during the seminar illustrate the conditions. This discussion is limited to cofferdams which are braced structures excavated inside to allow access for construction. The common procedure is to drive sheet piling and then alternatively install bracing and excavate. They can be located either on land or in water. Loads are applied by soil, water, surcharge pres-sure, eccentricities, and impact loads. The loads are resisted by the sheet piling, the bracing, and the soil below the bottom of the excavation; each of these three components must be capable of resisting the applied loads.

Jan 1, 1987

By Emre Biringen

"Results from a small-scale laboratory experimental program show the changes in the vertical stiffness and strength of a soft clayey soil adjacent to the shaft of an inserted pile (i.e. expansion of a cylindrical cavity). The experimental program provides a realistic axi-symmetric physical model of an element of a cylindrical pile and the surrounding soil. The study interprets the improvement and assesses its magnitude in vertical stress-strain-strength properties of a normally consolidated soft cohesive soil in response to preloading impact in the radial direction. The results verify that insertion of a cylindrical pile causes densification of surrounding soil in a radial direction due to change in stress state around the pile, and thus consolidating and stiffening of the soil.The test results indicate that most improvement in modulus and strength takes place within a distance of 4 times the radius of a pile, though significant improvement is realized to a distance of 8-10 times the radius, beyond where there is negligible effect. Settlement characteristics of the surrounding soil in a zone of 12 times the pile radius improve significantly after the formation of a cylindrical cavity. The miniature vane shear strength tests show a 1.5 times increase in a zone of 4 times the pile radius compared to the strength at 10 pile radii. The results also imply that the spacing of cylindrical piles should not be more than 4 to 10 times pile radius, so that the surrounding soil matrix may improve the vertical bearing capacity under any foundation or embankment loading.INTRODUCTIONThe engineering community is familiar with different techniques to improve the bearing capacity and settlement characteristics of weak cohesive and organic soils. Some of the in situ techniques to improve the properties of soft ground (e.g. soft clays) prior to placement of foundations are vertical preloading, deep cemenUlime mixing, stone columns, and grouting (Henn 1996; Moseley 1993). In addition to these methods, researchers have recently showed interest in achieving soft ground improvement by means of applying radial compression method for which different names exist including expanding pile (Kelleher et al. 2001 ), Preload™ Pier (Biringen and Edil 2003), and sand compaction pile (Lee et al. 2004). Handy (2001) has described how preloading can also be achieved by imposition of radial loading in soft ground with an expected improvement in stiffness. The idea behind the latter method is densification and consolidation of soft soil in the radial direction by controlled displacement for which the process can be viewed as a cavity expansion problem (Vesic 1972)."

Jan 1, 2005

By Babak Mamaqani, Pirooz Barar

The Moanalua trestle spanned over Moanalua Stream, Honolulu, HI and was designed to accommodate construction of five 10 feet diameter cast in drilled hole (CIDH) piers as a part of Honolulu Authority for Rapid Transportation (HART) project. Due to the proximity of piers to the existing bridge, the trestle was elevated 20 feet above grade. Stratigraphy of the site consisted of shallow depth of fill and 150 feet of loose to very loose recent alluvium (soft clay) underlain with stiff to hard old alluvium (stiff clay). CIDH casings were installed by a rotator or oscillator depending on the diameter of the piers. The challenge was to design the trestle, not only for heavy gravity loads, but also to resist significant lateral loads from rotator and oscillator with minimal deflection. Series of piles, called reaction piles, were integrated into the trestle at each CIDH pier location to provide adequate lateral support for the rotator/oscillator. Due to the lack of information regarding soil Young’s modulus (E), a methodology was developed to calibrate and calculate E with two methods. Extensive analyses using LPILE and finite element analysis program, PLAXIS, were performed to model reaction piles and calculate lateral deflection. PROJECT SPECIFICATIONS The Honolulu Rail Transit includes 20-mile route and 21 stations to be built from East Kapolei to Ala Moana Center, with $1.55 billion construction budget. The project is divided into two phases as shown in Fig. 1: Phase 1 which connects East Kapolei to Aloha Stadium with expected operation in late 2020, and Phase 2 which connects Aloha Stadium to Ala Moana Center with expected operation in 2025.

Jan 1, 2019

By Ashutosh S. Dhar

Cast-in-place piles were examined in this paper from the viewpoints of construction quality, axial capacity, and load-displacement responses. The results of ten 450 mm diameter (18? f) bored piles, installed in a soil deposit of silt to medium dense sand using the method of percussion drilling, were tested under static loads. The results of the pile load tests were used for evaluation of various design methods of calculating pile capacity. The study revealed that the design methods based on the concept of critical depth underestimated the ultimate skin fiction. Thus, the applicability of the critical depth concept for design of bored piles under the soil condition considered may be unreliable. The estimated skin friction factor, ß, was too low in these methods. The Tomlinson method and the Neely method provided the best prediction of the ultimate skin friction. The methods used for calculating end bearing resistance were found to provide a conservative estimate of the resistance. During pile load tests, a settlement of 5 to 6 mm was required for full mobilization of skin friction for the piles in loose sand, while larger settlements (> 10 mm) were required for piles in denser soil. The ultimate skin frictional resistance was observed to be low for piles in loose sand.

Jan 1, 2006

By A. Bozorgzadeh, B. M. Jensen, B. N. Koelling, B. R. Murtaugh

"The Service Base mooring system originally consisted of two general types of structures, 19 timber piles cabled together and steel three-legged pipe piles. The St. Louis District fleet moored to the fleet barges which were tied off to shore-side concrete deadman and supported on the landward side by the timber and steel piles. The purpose of this project was to replace the existing floating wharf mooring system at the St. Louis Service Base. The Marine Design Center of the U.S. Corps of Engineers developed a three pile cluster system concept. The clusters consisted of one vertical pile and two batter piles. Piles in rock sockets were selected to resist the uplift loads due to high wind loads on the tall, spare lock gates stored at the floating wharf. This paper focuses on the design of the rock sockets for steel pipe piles with large uplift loads and the lessons learned during the design and construction of this system.INTRODUCTIONBackgroundThe U.S. Army Corps of Engineers’ St. Louis District is located at the critical transition point on the Mississippi River where it is a “locking river” north of St. Louis and an “open river” to the south. The St. Louis District is responsible for maintaining navigation channels on the Mississippi River, the Illinois River and the Kaskaskia River. It is also responsible for the operation and maintenance of five locks and dams within its geographic boundaries.The St. Louis District utilizes a fleet of vessels (dredges, crane barges, motor vessels, and barges) to support the navigation mission identified above. The St. Louis District Service Base, located in St. Louis, Missouri, serves as the base of operations for the district fleet. This riverfront facility originally consisted of a floating wharf, a railroad trestle, and a walkway down the river bank to the floating wharf. Historically, there have been two fleeting areas at the Service Base. The main fleeting area was approximately 965 feet long and consisted of six fleet barges (Figure 1). This area supported the Dredge Potter and its attendant fleet. The upper fleeting area was approximately 1,050 feet long and consisted of various stop log, crane and work barges, dredge pipe pontoons and work flats."

Jan 1, 2017

By A. J. Partos

The figures and tables referred to herein are presented in the Proceedings; Volume I, Pages 309 through 316. The 61-story One Liberty Place, at 315 m., is the tallest building 1n Philadelphia and was in 1987 the ninth tallest building in the world. One Liberty Place is supported on drilled piers socketed in heterogeneous metamorphic rock. Design load distribution was 40% on the base and 60% by shaft resistance. Drilled Pier G-10 supporting a T13-A type outrigger column was instrumented. There 1s no uplift load on the exterior outrigger columns. This column supports a 53,850 kN compressive load which includes a 13,440 kN windload. Table 4 presents experimental parameters from straight line interpolation of Mohr failure envelopes for the Wissahickon schist. Lowest values of cohesion (12,200 kN/m2) and angle of internal friction (19°) are at a 50° - 59° angle of foliation. Figure 3 presents a typical pier supported by shaft resistance 1n decomposed (D) and coreable (C) rock and by end bearing (B).

Jan 1, 1991

By Tracy Brettmann, Melis Sutman, C. Guney Olgen

"The use of energy piles for geothermal heat exchange has been steadily increasing during the last decade, yet there are still pending questions on their behavior during temperature changes. This paper focuses on the thermo-mechanical response of three full-scale energy piles installed in Richmond, TX. The behavior of test piles subjected to thermo-mechanical loadings was studied in situ with the aim of quantifying the thermal influence on the performance and capacity of energy piles. An extensive field test program, including conventional pile loading tests and application of heating-cooling cycles was conducted on the test piles during a period of six weeks. For thermal load applications, the heat exchanger fluid with maximum temperature of 113°F (45°C) and minimum of 47°F (8°C) was circulated in the geothermal loops placed at the center of the test piles. Optical fiber sensors, vibrating wire strain gages, thermistors and thermal integrity profile wires were installed to monitor the strain and temperature variations along the energy piles throughout the field tests. The strain and temperature profiles during heating-cooling cycles on the test piles under static loads and without a maintained load were monitored to investigate the effect of thermo-mechanical and pure thermal loads on the energy piles, respectively. Conventional pile load tests were applied before and after the application of thermal cycles. The results of the pile load tests are compared to evaluate the effect of temperature cycles on pile capacity.IntroductionEnergy piles are deep foundation elements designed to access and exploit the relatively constant temperature of the ground and its heat storage capacity for efficient heating and cooling of buildings. The deep foundation elements that are already in place for structural support are integrated with adsorber pipes to perform as heat exchangers connected to ground source heat pump (GSHP) systems. With the use of energy piles, the heat energy is fed into and withdrawn from the ground for cooling in the summer and heating in the winter, respectively.Energy piles present an innovative way to harvest near-surface geothermal energy and to provide lower carbon emissions, however, there are still pending question on their performance. During heating-cooling cycles, energy piles experience temperature changes, which result in expansion or contraction of the piles."

Jan 1, 2017