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By Brian Metcalfe, Kord Wissmann, Gianni Martinez

The Middle East consists of vast deserts that reach temperatures up to 50°C (122°F), with some areas characterized by endless sand dunes. When project team members selected the location for a large new transportation project, little did they know that the site would be characterized by soft, nearly normally consolidated silt and clay extending below a thin sand crust. Searching for solutions, the design team elected to reinforce the sub­surface with rammed aggregate pier ground improvement elements and wanted verification that the method would stand the test of prolonged static loads. Because the concrete pave­ments would serve to spread the load, a "zone load test" was performed, consisting of applying a uniform bearing pressure of 150 kPa (22 Psi) over a 7.5 m (25 ft) square concrete footing. Unlike individual pier load tests, the zone test allowed the project engineers the opportunity to confirm design parameter values under large­loading area conditions, a situation not often available to most designers. This paper presents the results of the zone load test, which may be interpreted to better understand design parameter values, and is of particular significance because it adds a valuable contribution to the relatively few numbers of "group load tests" available in the literature for ground im­provement applications.

Feb 1, 2024

By Masakazu Takano, Koji Suzuki, Naotoshi Shinkawa

"Cement deep mixing (CDM) method successfully applied to a marine construction project in northern Vietnam is reported. The method is classified as wet method, in which cement slurry is injected into the ground. Thickness of clayey deposit subjected to improvement is from 20 m to 28 m, and the total volume of CDM improvement exceeds 460,000 m3. This is the first massive application of CDM method in the region. Three CDM barges, each equipped with four mixing shafts, were brought to the site in order to finish CDM work within a period of seven months. Cement content used in the work was 180 kg/m3 and water-cement ratio of slurry was 100%. Unconfined compression strength of stabilized soil was 1,200 kPa to 1,600 kPa in average with coefficient of variation from 0.3 to 0.4. Statistics analysis of the strength with these values gave percentage of lower strength less than 10%. Trial use of needle penetration test performed to study strength profile of a CDM column is also reported.INTRODUCTIONThe site of Lack Huyen Port Infrastructure Construction Project is located in the sea adjacent to Cat Hai Island, offshore Hai Phong city which is around 100 km east of Hanoi, the capital of Vietnam. Left side of Fig. 1 shows the location of the site. The project contains development of container terminal, dredging of waterway, construction of sand protection dyke to prevent waterway from being buried, and bridge construction to connect the island to the mainland.Joint venture of Penta Ocean Construction and Toa Corporation was awarded Package 6 of the project, in which reclamation of container terminal area, retaining wall construction and terminal road construction were included. Plan of the site is presented in right side of Fig. 1. The site work has been started in June 2013 and is scheduled to finish within 4 years."

Jan 1, 2015

By Dewey W. Geary, Rachael V. Bisnett, R. Michael Bivens, Thomas G. Andrews

"The powerhouse for the Red Rock Hydroelectric Project is being constructed at the toe of the existing U.S. Army Corps of Engineers’ Red Rock Dam immediately adjacent to the existing stilling basin retaining wall. The powerhouse excavation extends though overburden and 40 feet into rock. Prior to rock excavation, a grouting was performed around the excavation for the purpose of increasing the strength of zones of fractured rock. For the majority of the perimeter, the rock was fairly tight and grout takes were relatively low. However, for a 160 foot extent along the landside of the excavation, extensive grouting was required to treat a two to five foot thick zone characterized by artesian flows from grout holes on the order of 20 gallons per minute (gpm) or higher from a voided zone in rock that was partially filled with sand, clay, and rock fragments. This paper discusses the treatment measures used to fill and improve the strength of this zone, which ultimately entailed a combination of thick cement grout and polyurethane grout, holes spaced as close as 18 inches on-center, and two additional rows of grout holes.IntroductionThe Red Rock Hydroelectric Project (Project) is currently under construction at the existing U.S. Army Corps of Engineers’ (USACE) Red Rock Dam on the Des Moines River near Pella, Iowa. At peak generation, the Project will generate up to 55 MW with an average annual energy output of 178 gigawatt-hours.The powerhouse for the Project will be located at the toe of the existing dam immediately adjacent to the existing stilling basin retaining wall. The powerhouse excavation extends up to a depth of 40 feet into rock through the St. Louis Limestone and terminates in the Warsaw Limestone. Prior to rock excavation, grouting was performed around the excavation for the purpose of improving the strength of zones of fractured rock. An auxiliary benefit of the grouting was reducing seepage into the excavation. Grouting began on July 20, 2015 and ultimately concluded on September 26, 2015.Drilling and grouting occurred as planned on the riverside (southwest) of the excavation along the cellular cofferdam and stilling basin wall (grout holes P-1 through S-13) and on the upstream (northwest) side of the excavation along the secant pile excavation support wall (grout holes P-14 through S-19) (refer to Fig. 1). The rock in these areas was generally tight with relatively low grout takes. However, on the landside (northeast) of the excavation (grout holes P-20 through P-28), partially infilled voids and artesian flows were encountered during drilling generally between depths of about 28 to 40 feet."

Jan 1, 2016

By Glen M. Bellew, James F. Mehnert

"The Kansas City District-United States Army Corps of Engineers has completed the design modification of a pile supported floodwall located along the Missouri River in Kansas City, Kansas. This deep foundation supported floodwall protects over 2 billion dollars in infrastructure, is approximately 17 ft (5.2 m) tall and is 1,446 ft (440.7 m) long. Design modifications included the addition of a row of drilled shafts and the addition of relief wells. Typically, deep foundation design is controlled by total stress analysis and undrained soil strength. Neither controlled design at this site, where effective stress and drained strength controlled. During high river stages, artesian pressures develop, leading to a reduction in both effective stress and pile capacity. Deep foundation analysis software available to the designer does not allow these effective stress conditions to be directly entered, so a unique way was developed to account for them. A load test was performed to verify the design. During load testing, the supporting ground was unsaturated and had effective stress conditions different from those that controlled the design. A load test evaluation process involving unsaturated soil mechanics was developed and performed. This paper will share both the effective stress design process used and the load test interpretation process performed.INTRODUCTIONThe Fairfax-BPU Floodwall is part of the Fairfax-Jersey Creek Flood Protection Unit in Kansas City, Kansas. The floodwall was built in the 1940s and currently provides Missouri River flood protection for over 2 billion dollars of infrastructure in the Fairfax Industrial Area. The floodwall averages 17 ft (5.2 m) in height, is 1,446 ft (440.7 m) in length and is divided into 35 separate monoliths. The originally constructed foundation support for each of these monoliths typically consisted of three rows of seven tapered steel monotube piles, each roughly 20 ft (6.1 m) in length. All monontube piles are tipped in sand, well above bedrock."

Jan 1, 2016

By Racquel Nottingham, Freddy Lopez, Ole Gadermann

The ongoing urban development is a global phenomenon, placing has high demands on urban infrastructure (housing, public services, transportation, telecommunications, etc.). Micropiling is one of the most successfully implemented deep foundation technologies in urban interventions, and in densely populated and built-up areas. The use of micropiles enabled the implementation of several solutions within short time frames, with minimal disturbance to the daily activities of the population. Since urban interventions usually represent a very important investment and have an economic impact, special attention should be paid to the serviceability of the urban infrastructure in the middle and long term. For the foundations, the design loadbearing capacity of the used structural elements needs to be guaranteed during the planned life time of the structures. In the case of micropiles, it must be ensured that the steel load bearing elements are effectively protected against corrosion. This paper presents the structural design of permanent self-drilling micropiles, subject to tension due to uplift loads. For the case study, different micropile systems - available worldwide - will also be evaluated. For the afore mentioned micropile systems, the design considerations regarding the durability of the reinforcement, based on their corrosion protection approaches, will be presented in this paper.

By Richard Hanke, Franz-Werner Gerressen

"The twin decked Alaskan Way Viaduct is a passage to Seattle’s downtown waterfront and of great economic importance to the city. In 2001, the Nisqually earthquake damaged the viaduct and led to the redevelopment of this corridor. The project includes two miles of 57.5 ft diameter bored tunnel beneath downtown Seattle and a stretch of new highway and overpass bridges at the southern tunnel entrance. State-of-the-Art special foundation equipment was mobilized for the project to perform a broad range of geotechnical construction. Applications included soil mixing and jet grouting for confinement cells around new bridge foundations, large diameter secant pile walls for the Tunnel Boring Machine launch portal along with an extensive jet grouting regime for ground improvements within the tunnel alignment. This paper will study the evolution and use of advanced special geotechnical construction equipment and describe its application at the Alaskan Way Viaduct Replacement Project.INTRODUCTIONThe evolution of geotechnical construction equipment continues through innovative applications and continued modification or enhancement of machinery. Similarly and in parallel, market expectations continually demand more in terms of construction speed and performance. Together, market demands and contractor innovation have led way to the development of specialty geotechnical construction equipment with capabilities previously not seen feasible or possible. Several examples of this scenario have recently developed during design and construction of the Alaskan Way Viaduct Replacement Project.The Alaskan Way Viaduct Replacement Project is a joint project between the Federal Highway Administration (FHWA), the Washington State Department of Transportation (WSDOT), and the City of Seattle. Three build alternatives were under consideration for replacing the Alaskan Way Viaduct: the Bored Tunnel Alternative, the Cut-and-Cover Tunnel Alternative, and the Elevated Structure Alternative. Ultimately, the bored tunnel option was selected as the best value approach. The project includes two miles of 57.5 ft diameter bored tunnel beneath downtown Seattle and a stretch of new highway and overpass bridges at the southern tunnel entrance. Several other associated improvements tie into this project that will ultimately lead to the complete demolition of the viaduct and redevelopment of Seattle’s waterfront."

Jan 1, 2015

By Quanchen Sun, Mohammed Z. E. B. Elsahife, Anthony Fisher, Chris Barker, Jennifer Schooling

A review of the literature shows that pile integrity is a significant concern in pile construction. Recently, a new integrity test, thermal integrity profiling (TIP,) has been put into use in foundation construction. It measures temperature changes and thermal profiles of concrete during curing. Heat generation and dissipation of early-age concrete is determined by the concrete mix, the ground conditions and the shape of concrete structure. The current data interpretation practice is primary based on experience. Anomaly detection through direct analysis of temperature profiles is currently indicative or suggestive and temperature signatures are usually similar, and numerous causes are not easily isolated. The core of the TIP testing technique, i.e. collecting detailed temperature measurements along the pile during the hydration process, is promising but a new interpretation approach is required. In this paper, a new interpretation approach has been developed in which TIP constitutes the first step. An investigative staged process is then followed to establish and assess the anomalies in the problematic regions along the pile employing the combined use of detailed finite element (FE) simulations, the actual temperature data from TIP and genetic evolution algorithms. In each stage, more details could be revealed about the anomalies being investigated including, ultimately, location, size and shape; this staged process enables practitioners to follow a riskbased approach and decide whether or not to pursue subsequent stages depending on the results they get at the end of each stage. This new approach, depending on the stages required for the analysis, will potentially avail practicing engineers of crucial test results about the quality of the pile immediately following pile construction, hence enabling repair and remedial work straight away at a lower cost.

May 1, 2022

By Mu Chen, Ye-Shuang Xu, Dong-Wei Hou, Shui-Long Shen, Huai-Na Wu

"This paper presents a laboratory investigation on the mechanical behaviors of the cement-clay admixture improved by polypropylene fiber. Cement can significantly improve the clay admixture. The fiber additive also improves the strength and ductility of the improved clay. The Unconfined Compression Strength (UCS) of the polypropylene fiber-reinforced cement-clay presents an overall trend to grow with the increase of fiber length. The improved clay reached its peak strength at the fiber content of 0.5%. Then the UCS of the improved clay will slowly reverse if the fiber content continues to rise. For study of curing time, improved clay behaves better in its early strength, but an inhibition will be brought about if fibers are excessive.INTRODUCTIONGround improvement technology is essential for construction of structures in soft ground. Some traditional techniques often cost much but result in little. For instance, along the coastal region of China, soft ground is often improved by backfill with high quality sandy soil transported far away, leading to high additional haulage costs and long construction period. Reutilizing the excavated soil as backfill or subgrade after treatment, by contrast, will be more economical and effective (Hufenus et al., 2006). Many researches have been conducted to improve the compression strength of soft soil, among which, the method of mixing the soft soil with cement and fly ash is one of the most common ways (Kolias et al., 2005; Horpibulsuk et al., 2009; Porcino et al., 2012). It is known that soil resists well against compression and shear force but behaves poorly in resistance to tension. Therefore, utilizing tensile elements such as fibers and strips to improve the tensile strength will be effective because of its strength isotropy, better durability and cost effective (Haeri et al., 2000; Kaniraj and Havanagi, 2001; Consoli et al., 2010)."

Jan 1, 2015

By Bartho J. Admiraal, Antoine Feddema

Pneumatic sinking of caissons has been established from mid-19th century. The technique of pneumatic sinking has been applied on many projects for underground construction up to depths over 20m below groundwater level since that time. Volker Staal en Funderingen, a known deep foundation contractor in the Netherlands, was awarded two contracts in 2015 for sinking in total 2 caissons in Hamburg (Germany) to large depths (over 30 m (100 ft) and two projects near Amsterdam (the Netherlands). The latter concerned two gate chambers for the world’s largest sea-lock, one of them was 55x81 m2 (180x266 ft) to a depth of 25.5 m (84 ft), which would mean a world record for pneumatic sinking! But with depths and dimensions like these, the deployment of personnel is the main limiting factor for production, despite all developments to date. It was decided to develop a remote controlled process, including the necessary equipment and monitoring systems. Monitoring not only the kinematics of the equipment in the working chamber and the production parameters related to the excavation but also of the structural behaviour of the sea-lock gate chambers was essential for approval of this innovative execution method. The lay-out and the sizes of the largest caisson the structural integrity was extremely critical for torsion and bending moments. A displacement controlled execution by the observational method was therefore required. In engineering a new approach for modelling the semi-continuous failure mechanisms of the soil was needed to understand the sensitivity of the excavation process and to define limit values for the execution. In the paper these structural and geotechnical issues will be explained together with the experiences during the execution.

May 1, 2022

By Anjana C. P, K. Ranga Swamy

The hilly regions of Kerala are severely affected by excess rainfall, causing tremendous damage due to landslides and slope failures. It is necessary to strengthen the existing slope profiles to prevent such disasters and avoid their risk to human lives and civil infrastructures. This paper studies the effect of micro pile to reinforce the slopes in Idukki district of Kerala, where slope failures are frequent. Three-dimensional slope stability analysis is carried out on slopes from the Idukki to obtain safety factor values using the MIDAS GTS NX program. The slope is fully saturated herein by taking the model's piezometric surface at the ground level to simulate high rainfall intensity. The critical slopes are then modelled with micro piles to analyze their effectiveness in improving the stability under static conditions. Different micro pile arrangements are considered, and a series of slope stability analyses have been carried out to obtain the optimum configuration with the required safety factor. The FOS values increased by more than 50% with micro piles for all the slopes. The optimum micro pile arrangement obtained for each slope shows that micro pile distribution between the toe and middle of the slope is an effective location for reinforcing slopes.

Sep 1, 2022

By Qingwei Joshua Ong

Tension piles, also known as uplift or anchor piles, are necessary to resist uplift forces that might cause structural distress. In excavation projects, most uplift forces are developed because of hydrostatic pressures, and so tension piles are subjected to a great deal of tensile forces. Most current methods of design for tension piles completely neglect the tensile strength contribution of concrete, relying only on the steel members to carry the tensile stresses, resulting in an overly conservative design. The stressstrain behavior of the composite material of concrete and steel must be considered for a realistic simulation of tension piles. This paper will examine a case on a tension bored pile in typical soft clay to demonstrate the importance of considering the tension strength and tension softening of the concrete.

Nov 1, 2022

By Bruno Vingiani, Alessandro Bertero

"The use of Artificial Ground Freezing (AGF) for temporary soil strengthening and seepage control is an effective alternative to grouting when dealing with soils whose degree of finesses would imply the use of highly expensive chemical grouts. However, compared to grouting, the application of this improvement technique usually needs a more accurate preliminary soil investigation campaign and a design assisted by specific calculation software. Besides a general description of the main features of this technique, the paper will describe a recent application of AGF carried out in Rome to underpass an existing metro station.INTRODUCTIONNatural ground freezing occurs seasonally or permanently (permafrost) in some areas of the globe close to the poles and can negatively affect the engineering performance of underground structures. On the other hand, Artificial Ground Freezing (AGF) is man-made controllable freezing process that can be used in foundation engineering to temporarily strengthen the ground and create a barrier to the passage of groundwater. During the process, the heat is extracted from the soil in a cylindrical shape around a number of freezing pipes installed into the ground. This action produces columns of frozen soil, which expand gradually till they merge and create continuous frozen wall. The thickness of this barrier can be regulated according to the specific project requirements. Nowadays, AGF technique is applied to a wide range of foundation engineering problems where soil stability and groundwater flows are an issue (Pimentel et al. 2011, Haß and Schäfers, 2013). Typical applications include the temporary stabilization and waterproof of the ground around the excavation profile of mined tunnels until the construction of the final lining (Figure 1).The case history described in this paper deals with a recent application of AGF carried out during the construction of metro Line “C” in Rome. Specifically, this technique has been applied to allow the construction of two single-track mined tunnels running underneath an existing metro station belonging to Line “A”. In that case, the AGF has been evaluated by the Designers as the only possible solution for improving the mechanical and hydraulic characteristics"

Jan 1, 1900

By J. Gniel, L. King, C. Gaudin, C. O’Loughlin

"This paper presents some recent advancements in centrifuge modelling, which enable the installation of displacement piles to be performed in-flight while measuring ground responses. Details and results are provided from a series of experiments where 21 full-displacement piles were installed into a sample of consolidated kaolin clay at 40g. The piles were pushed into the sample at a constant rate of penetration, with installation reaction loads and pore pressures measured. Insight into the installation effects of the full-displacement piles was obtained by undertaking in-situ testing pre- and postinstallation of piles. The findings show that centrifuge testing has the potential to play an important role in furthering the current understanding of displacement pile behaviour and installation effects.INTRODUCTIONDisplacement piles and displacement ground improvement columns cause soil to undergo significant distortion and shearing during installation, which alters the soil properties. It is essential to consider these changes in soil properties to estimate the behaviour of pile foundations with higher degree of accuracy. However, the installation effects of displacement piles are widely considered as one of the most difficult geotechnical mechanisms to model, both analytically and numerically, and experimental data is needed to advance the current state of knowledge.Theories, analytical and semi-analytical, have been developed to describe the displacement pile installation process. Randolph et al. (1979) applied the cylindrical Cavity Expansion Method (CEM) to model the installation of a displacement pile in a fine grained cohesive soil. However, cylindrical CEM only considers the field variables in radial coordinates, and hence the soil-pile interface can only be modelled as a frictionless material. Baligh (1985) introduced the Strain Path Method (SPM), which assumes soil flows around the tip of a displacement pile. SPM was shown to model the stress and strain fields, particularly within close proximity to the pile, more accurately compared to the cylindrical CEM. While these methods account for the installation effects of a displacement pile and can be used to estimate a resulting ultimate bearing capacity, they are unable to describe the load-settlement behaviour of such piles. With the added complexity of group effects, existing analytical methods do not provide a means to accurately calculate the ground response to the installation of a group of displacement piles in a cohesive soil.The advancement of computational power, numerical techniques and constitutive models has improved the accuracy of numerical analysis, particularly in regard to modelling pile installation. However, even with advanced techniques, Finite Element Method (FEM) suffers a number of disadvantages due to the large deformations, which results in mesh distortion and tangling. Mesh-free methods such as Discrete Element Method (DEM), Smoothed Particle Hydrodynamics (SPH) and Material Point Method (MPM) are the next generation of computational techniques that are able to deal with large deformation problems. However, these advanced techniques are computationally expensive, complex and yet to be incorporated into commercial packages. Such methods are considered to still be in the development stage and are yet to provide a complete solution to pile installation problems."

Jan 1, 1900

By Adnan A. Malik, Tadashi Maejima, Jiro Kuwano

"Previous studies revealed that the helix deflection reduced the end bearing capacity of screw pile in dense ground even if the installation process is completed with minimal soil disturbance. The ultimate end bearing capacity in dense ground is difficult to achieve during the full-scale pile load test due to the limitation of the loading system. Therefore, in the present study, model scale of testing is selected to investigate the effect of helix deflection on load settlement behavior of single helix screw pile under increasing stress level. It is observed from the test results that the applied surcharge pressure, which is used to simulate the effect of stress level, is decreased with increase in model ground thickness. This decrease in the stress level is due to the frictional resistance between the container wall and sand. It is also observed that the end bearing capacity of screw pile increases with the increase in stress level but at gradually decreasing rate. The test results indicated that the helix deflection during the pile load test should not be more than critical deflection (0.72 mm average) of the helix to avoid any reduction in the end bearing capacity of screw pile. The helix deflection, which is measured after the pile load tests are also compared with the equations of flat circular plate having uniformly distributed load over the plate with simply supported and fixed inner edges.INTRODUCTIONThe screw pile consists of a central steel shaft with one or more helices attached at different location on the central shaft. The installation mechanism of screw pile consists of torque and pushing force. The screw pile installation mechanism can affect the unit weight of the ground during its installation. This effect is small in cohesive soils but it is quite noticeable in loose to medium dense sands (Adams 2011; Santos et al. 2013). The pushing force should be controlled in such a manner that pile penetration should be at least 80% of the pitch of the helix, during each revolution (Perko, 2009)."

Jan 1, 2017

By Frederic A. Verheyde

The CPT pile design method of the ‘Laboratoire des Ponts et Chaussées’ (LPC) uses the cone resistance (qc) for the design of axially loaded piles. It was originally proposed in 1982 and was revised in 1993 and 2012. It has been widely used in France for several decades and is included in the current French pile design code. The objective of this paper is to summarise the two first versions (1982 and 1993) of the method and to detail the most recent one as described in the current French pile design code (AFNOR 2012).

Nov 1, 2022

By Camilla Favaretti, Benjamin Turner, Anne Lemnitzer

Pile foundations are extensively used in the construction of various types of superstructures, including tall buildings, bridges, freeways and offshore structures. A fully constrained tip embedment such as a rock-socket offers an attractive solution for achieving significant tip resistance and improving the load-carrying capability of the foundation element. In profiles with very soft surficial soil, rock-socketing often provides the only reliable source of axial and lateral resistance. In preparation of a large-scale testing program on rock-socketed piles at UC Irvine (UCI) geared towards studying the magnitude of shear amplification at the rock-soil boundary of pile foundations, a pre-test model-scale experiment was executed in the UCI Structural Laboratory. The objective of the model-scale experiment was to iterate and validate the test setup, study the influence of important boundary conditions, assess instrumentation techniques and sensor placement, and to gain preliminary insight into the small-scale specimen non- linearity. In addition, this model-scale study provides ample opportunity to compare lateral performance parameters with analytically predicted lateral load behavior using traditional soil resistance functions and limit state analyses and explore new techniques for the derivation of soil resistance functions. The pile specimen had a pile diameter (D) of 10 inches and a total pile length of 125 inches. The pile was embedded in a 40 inch simulated rock socket overlain by 52 inch of medium dense sand (DR~50%). The pile extended 32 inches above the soil surface, where cyclic lateral loading was applied. The pile was installed in a laminar metal frame box with inside dimensions of 39 inches in width (W), 73 inches in length (L) and 86.1 inches in height (H) as shown in Figure 1. During testing, the box was restrained using a rigid bracing system consisting of concrete reaction blocks, wooden braces and steel girders.

Jan 1, 2018

By Fabrice Mathieu

The Cutter Soil Mixing (CSM) provides a cost effective solution for the rapid construction of retaining and cut-off walls using new equipment developed from diaphragm wall cutter technology. CSM consists of cutting and mixing drums mounted on compact hydraulic motors. Soletanche Bachy CSM has been designed to leave the space above the tool free, thereby mixing the soil efficiently during all the phases of the wall construction, with high penetration rates. The precise positioning and verticality of the wall is achieved using a kelly bar and full monitoring. Soletanche Bachy CSM is a versatile equipment which can be mounted on various carriers: pile rigs, hydraulic crane, carrier equipped with telescopic mast. The major phases of Soletanche Bachy CSM development are presented, including the results of an extensive trial carried out in Le Havre (France). The soil consists of hydraulic fill with soft soil lenses overlying sandy deposits. 20m deep panels were constructed to support a rectangular shaft. During the construction, and after its completion, the shaft was subjected to an extensive series of tests followed by a partial excavation. The paper discusses also the future development of the technique and its potential applications.

Jan 1, 2006

By Craig H. Olson

"Anew ship dock at a Philadelphia area refinery will be capable of docking the largest tanker to travel the Delaware River, the Stena V-MAX, which will induce significant lateral loads. The loads at the dock, a system of mooring dolphins and platforms, will be resisted by over 150 pipe piles, including some 20- and 30-in diameter, reinforced, concrete-filled pipe piles and H-piles. Construction included driving the pipe piles to the required ultimate capacity, flushing the pipe pile casing clean of overburden materials, followed by drilling rock sockets into the underlying Wissahickon Formation. The Wissahickon Formation is a complex subsurface that includes variations in depth to bedrock, rock quality, degree of weathering and the presence of very hard quartzite lenses or inclusions. Because of the problematic subsurface, the designers and client requested extensive pile dynamic analysis (PDA) testing by TRC Engineers (TRC).Before beginning, the contractor requested that TRC perform the WEAP (wave equation analysis program) to evaluate the proposed hammer (APE D30-32 open-end diesel) to drive the piles into the proposed bearing strata while maintaining allowable compression stress levels. The WEAP provided a prediction of blow counts and stresses for various ultimate capacities, and showed that for the HP14x89 piles with a required ultimate capacity of 480 kips, a blow count of at least four blows per in at a stroke of 8.0 ft was necessary. New Approachway RampThe PDA testing began at the new dock approach way ramp, parallel to the existing one. The new structure is a 300-ft-long by 21- ft-wide concrete deck supported on seven bents; each has two 24- ft-diameter steel open-ended pipe piles. Every pipe received an HP 14 x 89 x 80-ft pile that was later driven beyond the pipe pile tip to create a composite pile. The pipe piles were later cleaned of overburden materials and finally filled with concrete and rebar. At each bent, a cap was installed on top of each pair of pipe piles, and then a prefabricated concrete deck was added."

Jan 1, 2008

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 Brian McGlynn

There are many factors that can result in a site characterization being limited. For example, a client may undervalue the importance of a good geotechnical report, or an owner may feel that it would take too much time to perform an appropriate investigation among other reasons. For this project, neither was the case. The challenge was that the construction sequence of work required wick drains to accelerate the settlement of soil that had yet to be placed, resulting in the need to create a wick drain bid package based on unknown settlement parameters. This wick drain project took place in Long Beach, California, at the Long Beach Middle Harbor Re- development. For much of the past decade, the Port of Long Beach undertook a $1.5 billion redevelopment of two outdated terminals to create the Long Beach Container Terminal (LBCT). To achieve this goal, the existing terminals were demolished and the slip that serviced one of the older terminals was designed to be infilled to create the new area that would allow for the LBCT to manage 3.3 million TEUS (a commonly used freight term meaning twenty-foot equivalent unit) of cargo each year. Ultimately, the construction of the LBCT would be performed under multiple contracts to allow the new terminal to begin operation in a phased approach. Menard performed the wick drain installation under two out of three contracts, and this case history focuses on the challenges anticipated and faced under the second of these awarded contracts.

May 1, 2023