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By Mike Neill, O&apos

? Bypass soft soils near the surface ? Resist uplift loads ? Resist lateral loads ? Bypass scourable soils ? Bypass liquefyable soils ? Mitigate movement of expansive or frozen soils ? "Tune" foundations for vibrating machinery

Jan 1, 1998

By Mohammed Z. Islam

As cities are growing all over the world, the need for urban transportation facilities are on the rise. Designers (of these facilities) today are faced with a number of constraints for their design, of the most is the space limitation and impact of new construction activities to the community. A typical subway station, as the focus of this paper, is approximately 600 to 1000 feet long, 50 feet wide and 2 to 3 story high. With such a large volume of construction activities, it is easily realized why underground stations are becoming obvious choice for larger cities eventhough the cost could be 2 1/2 to 3 times as much as an aerial station and 4 to 5 times that of an at-grade station [O'Neil et. al.(1977)]. Since cost is an important factor which is always increasing, therefore, the designer should have a good planning, consider alternatives for design and come up with a realistic design with minimum impact to the community. This paper is about the geotechnical considerations that the designer should be aware of. PLANNING A 1977 report [O'Neil et. al.(1977)] on the construction costs for a number of underground subway stations indicate that about 4 0% of the cost is site-controlled, 35% is structural items, and 25% is finish and equipment. It is seen that of opportunity exists for cost savings in the site selection and proper use of the site. Once the site is selected, the cost of construction become controlled by urban conditions at the site, geotechnical conditions, station size and depth. Therefore, the design-solution is very much site-specific. The geotecnical designer should collect the following information at the early phase of the design:

Jan 1, 1993

By Mohab Sabry

Pile foundations are used extensively around the world to support both inland and offshore structures, including important structures such as nuclear plants and oil drilling platforms. The limit of the pile depth is currently predicted during the pile deriving process, given no chance for the designer to predict accurately the capacity of these piles prior installation. Furthermore, after pile installation, designer may not be able to modify the pile group design by increasing the number of piles and or changing the geometry of the pile group. This paper presents a numerical model for the case of single piles driven in homogenous sand using finite element technique and the theory of cavity expansion. The model is capable of simulating all the construction stages of concrete piles up to the maximum depth, which can be driven in sand and accordingly the capacity, which can be attained by these piles. The program "PLAXIS" is used to perform the proposed analysis. This model simulates the process of pile driving in terms of the changes in the earth pressure and the overconsolidation ratio acting along the pile's shaft. Based on the results of the present investigation, these depths can be predicted based on the pile geometry and the sand properties. Charts are given to provide these depths for given pile/soil conditions.

Jan 1, 2006

By Chu E. Ho

Field load tests on deep slurry stabilized bored piles have shown that end bearing resistance was unreliable due to soft toe conditions caused by debris accumulation at the bottom of the hole during pile installation. This is true whether bentonite or polymer slurry was used. Skin friction resistance was less affected by the slurry and is more reliable. A design strategy is proposed which ensures that an adequate factor of safety against the ultimate shaft resistance is maintained for any chosen design working load, such that a pile settlement of 12mm would not be exceeded.

Jan 1, 2002

By Peter Florian

At 5:50 am on October 1, 1992, the new $800 million Pittsburgh International Airport Midfield Terminal opened its gates to the world after five years of construction and more than 24 years of planning. Despite numerous design changes, this massive project was completed on time and substantially within budget. The importance of this airport to Allegheny County and the Pittsburgh region was recognized 24 years earlier by Allegheny County Commissioners Tom Foerster and the late Leonard Staisey. Staisey and Foerster established a program to acquire land for the "Airport of the Future".

Jan 1, 1993

By Virendra Singh

The load settlement behaviour of single pile or pile group may be obtained using computer based methods such as the finite or boundary element techniques. An alternative method of obtaining the vertical soil stresses adjacent to the Pile is presented Based on calculated stresses consolidation settlement for Piles foundation is obtained. This approach may be computationally more attractive than the more general finite or boundary element techniques.

Jan 1, 1996

By Rudolph P. Frizzi

This paper presents different deep foundation systems and associated settlement records for high-rise building projects in the coastal areas of southeastern Florida. An introduction to the sedimentary soil and soft rock geology in coastal areas of southeast Florida is presented, and the deep foundation systems utilized include: piles of varying length, pile supported mat, preload and short piles, and drilled shafts. The implementation and associated settlement monitoring data of the different deep foundation systems are described through case histories involving 20 to 66-story buildings. In addition, the deep foundation systems and settlement monitoring results for twenty-one additional high-rise building projects in the coastal areas of southeastern Florida are presented.

Jan 1, 2003

By Rick Deschamps, Brian Barkauskas, Aled Hughes, Abigail Stein

In central Washington, six miles south of the small town of Vantage, the flow of the Columbia River is harnessed by the Wanapum Dam which is part of the Priest Rapids Hydroelectric Project owned and operated by Grant County Public Utility District (GCPUD). Extending more than 8,300-feet from bank to bank, the dam includes left and right earth embankments, left and right concrete gravity sections and a 10-unit powerhouse. Adjacent to the right embankment is a concrete gravity spillway featuring radial gates measuring 50-feet-wide and nearly 70-feet-high. In the early 1960’s when Wanapum Dam was built, these seven-story spillway gates were the highest in the world. In late February 2014, 50-years into its service life, during a routine maintenance inspection, observant workers noticed a slight misalignment in the roadway deck curbs and handrails located on top of the spillway. Further survey and inspection efforts uncovered a 65-foot-long by two- inch-wide crack that spanned the full length of Monolith 4. On discovering the extent of the damage, GCPUD initiated immediate drawdown of the reservoir to relieve pressure on the spillway monoliths. Wanapum Reservoir and the areas directly downstream of the dam were immediately closed, boat ramps and inlets were left completely dry, campsites were closed and boating activity was banned on the lake until further investigations and remedial procedures were in place and completed. An extensive root cause analysis ultimately led to the conclusion that errors in the initial design calculations and late changes to the final spillway design led to a condition that generated tensile stresses in the concrete at the upstream face, which over a period of 50-years resulted in the formation of a crack along a horizontal lift joint located about 85-feet below normal pool elevation. Further analysis showed that, although visible distress was found at Monolith 4, there was nothing preventing this issue from happening at other locations along the dam spillway. Although no visible cracking was found in the other monoliths, repair procedures for Monolith 4 would have to be replicated at the remaining monoliths.

Jan 1, 2018

By Jacob Chacko

The Izmit Bay bridge, a 3-km-long suspension bridge crossing of Izmit Bay, Turkey is planned to be constructed in one of the most seismically active places in the world. The site, which has the potential to experience significant earthquakes associated with the relative motion accommodated on the North Anatolian Fault, is underlain by deep deposits of soft soils, and areas of unstable and liquefiable soils. Characterizing the seismotectonic setting, foundation soil conditions, potential fault locations, as well as other geohazards was a critical component for the project concessionaire to finance the project and obtain meaningful bids for bridge design and construction. Given the Build Operate Transfer (BOT) funding mechanism, executing this work in the least possible time was critical to the concessionaire?s financing scheme. Fugro was retained to provide geotechnical, geological, and seismological evaluations for the project region, and to generate data for contractors to develop reliable designs and bids. The uncertainties in these data made it difficult for the BOT concessionaire to finance the project and tender Bridge design and construction. The investment in an early and comprehensive site characterization program to evaluate and quantify those uncertainties allowed the concessionaire to save schedule, provide a robust bid basis to bridge contractors, and persuade banks to finance what was perceived to be a relatively high risk project.

Jan 1, 2011

By Robert E. Fosse

Driven 14-inch-square concrete piles were used as the foundations of Genentech Hall at the new University of California, San Francisco Mission Bay Campus. The five-story, steel eccentrically-braced frame building is currently under construction at a 43-acre property located in a former large shallow marshy inlet from San Francisco Bay. The piles were driven through 10 to 25 feet of fill and 20 to 60 feet of soft compressible Bay Mud into an underlying dense sand layer. Pile design capacities were developed for traditional allowable stress design, load factor and resistance design, and ultimate design criteria. The ultimate level capacities were for checks of loads occurring when the links in the eccentrically-braced frame yield during an earthquake. A load test program was performed to confirm pile design recommendations. Two test pile locations were selected for compression, tension, and lateral load tests to evaluate pile capacity and pile/soil stiffness under long-term, short-term and rapid loading conditions. Maximum test loads were 1000 kips downward, 350 kips uplift and 50 kips lateral. Foundation construction began by driving 34 indicator piles with a Delmag D46-32 diesel hammer of 113 foot-kips maximum rated energy. All indicator piles were monitored during initial driving using the Pile Driving Analyzer. Restrike data, obtained several days after initial driving, indicated significant pile-soil setup and typical pile capacity increases from 750 to 1000 kips. The majority of the 1242 production piles were then driven to acceptance criteria of 75 blows per foot and a minimum embedment of 10 feet into the dense sand bearing layer. Piles driven to full length without achieving the blowcount criteria were evaluated on a case-by-case basis. Acceptance of these piles was established by evaluating restrike data.

Jan 1, 2002

By Mario Terceros H., Bengt H. Fellenius

"ABSTRACTFour strain-gage instrumented bored piles were constructed in a sedimentary, dense to very dense, fine to medium sand in Santa Cruz, Bolivia. Two of the test piles were the normally used bored pile constructed with bentonite slurry and two piles were Bauer Full Displacement Pile (FDP). One of each pair was equipped with the Expander Body, an inflatable steel cylinder that on pressure-grouting provides an enlarged pile toe. Head-down static loading test were performed on three of the piles and a bidirectional test was performed on the fourth pile, a standard pile with Expander Body and a bidirectional cell placed immediately above the EB. The latter pile was tested in 3 phases. First by activating the cell, second, by a head-down test, and, third, by a repeat bidirectional cell test. The static loading tests proved the shaft resistance of the FDP pile to be about twice that of the standard bored pile and that the Expander Body more than doubled the toe stiffness. The strain-gage records showed that the standard bored piles had multiple bulges and neckings, which affected the evaluation of the axial stiffness and load distribution of the piles. The testing programme was used for a prediction event with 60 persons, ahead of the tests, submitting predictions of the load-movement curves for the test piles and also a capacity appraised from the curves.1. INTRODUCTIONOn April 23 - 26, 2013, the First International Conference and Seminar on Deep Foundations was held in Santa Cruz, Bolivia under the auspices of INCOTEC SRL, the UAGRM University, and the Bolivian Association of Civil Engineers and Chamber of Construction. To coincide with the conference, a research study on construction and static and dynamic testing of four instrumented bored piles was undertaken. To ""add spice"" to the conference, a prediction event was organized on the test programme. This paper presents the soil conditions at the site, the type and construction of the test piles, the outcome of the prediction event, and the results of the static tests.2. SOIL CONDITIONSGeotechnical studies comprising SPT and CPT tests with routine laboratory analysis were performed on recovered soil samples. Three SPT boreholes were put down at three of the locations of Pile TP1, TP2, and TP3, at 5.0 m distance from each other. The SPT procedure consisted of manual hoisting of the weight by three crew members pulling on ropes over a pulley supported by a tripod and letting the weight fall by gravity. The groundwater table lies at 3.5 m depth.Figure 1 shows diagrams of the SPT N-indices and the distribution of water content in the three boreholes. The SPT-indices show the soil density to be compact. The average water content is about 15 %, plus-minus a few percent."

Jan 1, 2014

By Mike Muchard

Augered cast-in-place piles are one of the most cost effective deep foundation options available to designers but have been largely underutilized due to skepticism associated with quality assurance and hence capacity. When installed correctly, unit friction values can rival any other competing foundation system. To this end, many means have been implemented to increase confidence in the competence of the foundation. One such method is load testing via the Statnamic test method. This paper presents an overview of the Statnamic test method, advantages and disadvantages of its use, and several case studies where Statnamic testing of augered cast-in-place piles confirmed quality construction, brought about design changes, or proof tested problematic installations.

Jan 1, 2000

By Lars Richter, Franz-Werner Gerressen

"The Eglinton Crosstown Line was conceived as the Eglinton Crosstown LRT, a partially underground light rail line, announced in 2007 as part of the Transit City plan, which included the implementation of six other light rail lines across Toronto.There were 43 stops planned for the Eglinton Crosstown LRT, 13 of which would be underground . For those underground stations a lot of specialty foundation works needed to be carried out. King piles, soldier piles with lagging and secant piles were mainly required fulfilling the tasks of installing the retaining wall system.The paper will focus on the original design and alternative solutions, discussing the benefits and limits of these. It will also explain the installation process in general as well as some specific features related to specific site conditions, e.g. limits in installation depth, soil characteristics etc. The required equipment will be explained showing the benefits and limits.INTRODUCTIONThe Eglinton Crosstown project is a 19-kilometre LRT line that will bring much needed relief to the transit woes of Torontonians. Traversing the city in an east-west slice across the midtown artery of Eglinton Avenue, the Crosstown rail line involves a combination of 15 underground stations and 10 atgrade surface stops. It is one of the largest transit infrastructure projects under way in North America today. Aecon has joined partners ACS Infrastructure Canada, Ellis Don, and SNC-Lavalin to form Crosslinx Transit Solutions (Crosslinx).As with many of today’s mega public transportation projects, the Crosstown LRT follows the Public- Private Partnership (P3) model. Aecon is an equal partner in the $5.3-billion Crosslinx consortium to develop the Eglinton Crosstown LRT project in Toronto. Upon the LRT's completion in 2021, Metrolinx, the region’s transit authority and also the project client/owner, will turn to the Toronto Transit Commission (TTC) to operate it. The impact of this highly anticipated LRT line on commuters in the Greater Toronto Area (GTA) is expected to be dramatic and immediate once the first train leaves the station five years from now. In fact, Metrolinx is estimating that within its first 10 years of service, the Crosstown line will be carrying 5,500 passengers per hour (in peak direction) and making 100 million passenger trips annually."

Jan 1, 2017

By John R. Wolosick

MACROPILES are defined as ultra-high-capacity micropiles, with working loads in excess of 250 tons. The piles are typically 9-5/8 to 24 inch (244 to 610 mm) outside diameter. They are drilled and grouted in place, with either large diameter steel bars and/or steel pipe reinforcement. The piles are typically tested to twice the working load. Piles with working capacities of up to 500 tons and tested to 1000 tons have been installed. The paper discusses MACROPILE design philosophy, construction techniques, and two case histories where this innovative foundation system has been installed. Macropiles are descended from micropile technology pioneered in the early 1950s by Fernando Lizzi of Italy.

Jan 1, 2006

By David B. Paul

"ABSTRACTThe US Army Corps of Engineers (USACE) has 704 dams in their inventory and over 100,000 miles of levees with a capital value of over $150 billion. Currently, there are 319 dams that are classified as high hazard and have actionable failure modes that will require structural modifications. The most frequent actionable failure mode associated with the inventory is seepage and piping. One of the most effective engineering solutions is the installation of a cutoff to limit seepage. Currently, USACE has over $1.5 Billion of cutoff wall projects under construction and/or design. Given the magnitude of the dam and levee safety issues, USACE is developing a new Engineering Manual (EM) titled “Seepage Control Cutoffs for Dams and Levees.” This EM covers all of the methods to construct cutoff walls. USACE has partnered with the Deep Foundation Institute (DFI) in preparation of the EM to ensure that it is comprehensive and draws from the expertise of the specialty foundation engineering companies that design, manufacture, and construct seepage control cutoffs around the world. The EM contains case histories as well as a comprehensive project statistical summary and guide specification paragraphs. The goal of USACE was to make the EM a state of the art document for use by Districts.HISTORYSlurry wall construction techniques were developed in the late 1940’s in Italy by ICOS. The first use of the slurry trench method of construction in the United States was by the USACE Memphis District in September 1945, to form a partial cutoff along the Mississippi River levee on the Arkansas side of the river just below Memphis, Tennessee. The idea for the project probably evolved from the use at that time of puddle clay trench cutoffs combined with the use of drilling mud for advancing borings. A paddle wheel mixing device was constructed for making slurry from native clays. Trenches were dug to a 20-ft depth using a trenching machine and to a 35-ft depth using a dragline with a 100-ft boom and 2-cu-yd bucket. Backfill was mixed in windrows at the site from hauled-in clay gravel and native materials and pushed into the trench by a bulldozer when the length of the trench was equal to about twice the trench depth. It is amazing that after almost 70 years, the technique is still about the same as it was when first developed by the Memphis District. A soilbentonite cutoff was constructed under the Kennewick Levee adjacent to the Columbia River as part of the McNary Dam Project in Washington by the Walla Walla District in 1952 The first application of a soil-bentonite slurry trench cutoff for control of underseepage at a major earth dam was at Wanapum Dam on the Columbia River in Washington in 1959.The first cement- bentonite cutoff in the United States was constructed at the Tilden Tailings Project to store tailings from the Tilden Mine in Michigan in 1976. The first cement-bentonite cutoff constructed at a dam on a river retaining a reservoir in the United States was completed in 1978 at the Elgo Dam (formerly the San Carlos Dam) in Arizona.The USACE has designed and constructed some of the deepest and most complex cutoff walls for dams since the 1970’s. The first major concrete panel cutoff wall constructed in a dam in the United States was at Wolf Creek Dam (Nashville District) by the ICOS Corporation between 1974-77. The dam has a long history of seepage issues associated with the karst geology that comprises the foundation. In 1968, about 17 years after first being impounded, wet areas, muddy flows in the tailrace and sinkholes in the downstream toe adjacent to the switchyard occurred."

Jan 1, 2014

By A. Eslami

In recent development of piled raft design, the contribution of both raft and piles to tolerate the loads is taken into account, depending on the stiffness and contributions of involved elements i.e.; piles, raft and surrounding soil. The piles are usually required not to ensure the overall stability of the foundation but to act as settlement reducers. One alternative method of foundation design is therefore to introduce piles purely as a means of improving or enhancing the stiffness of the base soil by structurally disconnecting the piles from the raft. In this paper, two and three dimensional finite element analysis of disconnected pile-raft systems are performed on three case studies including a 12-storey residential building in Iran, a 39-storey twin tower in Indonesia, and the 256m height of Messeturm tower in Frankfurt, Germany. The analysis include different geometrical parameters, e.g., pile spacing and embedment length, arrangement and raft thickness for foundation system to obtain the optimized design functions and to clarify the role of each parameter and method of analysis. The parametric study results and comparison to a few field measurements indicate that by concentrating the piles in the central area of the raft foundation leads to the optimum design with the minimum total length of piles. This achievement can be considered as a criterion for project cost efficiency. On the other hand, disconnected piled-raft systems can significantly reduce the settlements and raft internal bending moments. Finally, the comparison indicates that simple and faster 2D analysis has almost the identical results to 3D analysis which is complicated and time consuming.

Jan 1, 2008

By G. Price

The Building Research Establishment installed a base load cell in a driven cast-in-place pile prior to it being tested under vertical load. The monitored base loads were found to be significantly less than could have been predicted by current design methods. The less than expected capacity was attributed to the drilling out procedure. An electro-level system installed in a second similarly formed pile, provided detailed information on the performance of the pile under lateral load. The information obtained was used to check several current design methods for laterally loaded piles. The findings show the potential dangers of attempting to improve design parameters from only limited performance data.

Jan 1, 2010

By Andrew Port, Ali Ghandeharioon

Nonlinear seismic deformation analyses using the finite difference program FLAC were performed for a wastewater treatment plant to estimate foundation displacement and performance of two proposed trickling filters during the 2475-year event design earthquake. The effective stress based constitutive model UBCSAND, which captures the cyclic behavior of both the “sand-like” and “clay-like” materials, was used to model the dynamic response of the soil strata. Dynamic analyses of the site indicated that in absence of ground improvement or deep foundations beneath the proposed trickling filters, those structures would undergo horizontal displacements in excess of 1 m and short-term differential settlement gradient of about 400 mm over 50 m as a result of seismic and post-seismic settlements. Three mitigation options were considered for limiting the seismic displacements and differential settlement gradients of the proposed trickling filters. These alternatives include vibro-replacement stone columns, vibro-replacement stone columns plus supplementary cutter soil mixing (CSM) configurations, and pile foundations. Various layouts for each mitigation option were considered including the lateral extent of the ground improvement, CSM walls and pile spacing. Seismic horizontal and vertical displacements of the proposed structures as well as post-earthquake consolidation settlements due to dissipation of excess pore water pressures in soil layers were assessed in all the analysis alternatives. The analyses indicate that all the alternatives considered have the potential to provide a comparable level of seismic and post-seismic performance. However, for similar performance levels, the ground improvement options need to extend well beyond the edges of the proposed structures, while the piles can be limited to just beneath the footprint of the structures. INTRODUCTION Annacis Island Wastewater Treatment Plant (AIWWTP) is owned and operated by Greater Vancouver Sewerage and Drainage District and services a population of approximately 1 million people in Vancouver, British Columbia. Wastewater is generated by residential, commercial, and industrial sectors and the treated effluent is discharged to Annieville Channel of Fraser River on the south side of Annacis Island. AIWWTP is located on a 51-hectare site and was commissioned in 1975 as a primary treatment plant, but has had two major expansions to meet the population growth needs, and to improve the treatment process efficiency through the provision of secondary treatment of the liquid stream. The current expansion includes construction of additional solids contact tanks and secondary clarifiers. Future expansions include the construction of proposed additional trickling filters. New expansion structures are required to be designed for post-seismic operation after the 2475-year event design earthquake.

Jan 1, 2018

By Reda M. Bakeer

"Measurements obtained during load testing of two steel H-piles driven at a site in Northeastern Mississippi are discussed. The general site conditions, equipment used, testing procedures and results of the pile load tests are presented. Both piles were tested in compression and one of the piles was subsequently tested in tension. The piles were instrumented with strain gauges and extensometers to measure the mobilized soil resistance and pile movement. Three different “zero strain” conditions were used to determine the mobilized soil resistance and residual loads due to driving or a load cycle. It was concluded that the effect of residual loads on driven piles could be significant. Driving residual loads influenced the magnitude and distribution of the load transfer curves more than those due to a load cycle. Results of the tension test were impacted by the residual loads from the previous compression test performed on the same pile.INTRODUCTIONSeveral factors affect the performance of a deep foundation system including the subsoil conditions, loading settings, pile type and installation method. Residual stresses develop in piles particularly due to pile driving, but they are typically not accounted for in the analysis (Fellenius 2002). Siegel and McGillivray (2009) presented an assessment of residual loads measured during load testing of instrumented auger-cast-in-place (ACIP) piles. The magnitude and distribution of residual stresses along the pile shaft and toe depend on the pile installation method, previous load cycles and time effects. Poulos (1987) reported that residual load due to driving at the pile toe is independent of pile driving equipment and may significantly affect the results of a pile load test. Hunter and Davisson (1969) reported results of pile load tests performed in compression on fully instrumented piles driven in cohesionless soils along with a discussion of the effects of residual loads. Tension loads of about 445 kN (100 kips) were measured at the pile toe after driving. Unloading residual compression load at the toe was detected as “apparent” tension since the instrumentation was zeroed prior to the test. The researchers suggested a graphical approach to obtain the “corrected” load distribution curves considering that residual load will dissipate following the tension test. Holloway et al. (1975) conducted a study on the effect of residual stresses due to pile driving and developed a computer software that accounts for residual loads. Briaud and Tucker (1984) suggested a method to account for residual loads based on the results of 33 pile load tests performed in mostly cohesionless soils."

Jan 1, 2017

By Anne Lemnitzer

Full-Scale cyclic field testing was performed on a 3x3 pile group consisting of nine cast-in-drilled-hole (CIDH) reinforced concrete shafts and a comparable single-shaft in order to investigate group interaction effects. Both specimens were constructed with pile diameters of d = 0.61m (2 ft), fixed head boundary conditions, and placed in stiff clayey soil at a test site near the LAX Airport in Southern California. Internal instrumentation was installed in the single pile as well as in three piles within the pile group to obtain pile curvatures. External instrumentation controlled the lateral displacement of the specimens. A combination of experimentally and analytically obtained p-y curves for the single pile was used to simulate results for piles located in the group when field data were not available. All test specimens were tested to structural failure and excavated after test completion to investigate pile damage and plastic hinge formations. Calculated group interaction factors ranged between 1.0 at very small displacement levels of <2.5 mm (0.1 in), 0.8 at the initiation of the pile-soil-pile interaction, i.e. between 4 mm - 15 mm (0.16-0.6 in), and increased towards 0.9 near structural failure (displacement >25 mm or 1 in). A literature set of p-multipliers was found to reproduce an accurate fit to the available load displacement test data from the group.

Jan 1, 2010