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By Scott C. Vollmer

This paper seeks to examine some of the technical factors influencing the deflection of Mechanically Stabilized Earth (MSE) retaining walls based on the authors' field observation of numerous structures. Excessive deflections can be unsightly and can be perceived as wall failure. Deflections can cause cracking or gapping of the facing units and general misalignment. Deflection of the reinforced backfill zone behind the wall face can result in settlement of the backfill zone and adjacent pavement cracking. Deflections can be the result of excessive movement external or internal to the reinforced soil structure. This paper only examines internal factors affecting wall deflections. External factors such as foundation settlement are not discussed.

Jan 1, 2003

By Jiwei Duan

The deformation and load transfer behavior of a single soil-cement column are studied with the finite element method. The results show that there is an effective length for a soil-cement column. Beyond this length, the settlement of the column is approximately equal to a constant. The effective pile length is introduced to the concentric cylinder approach (Randolph and Wroth 1978), and an analytical formula for estimating the settlement of a single flexible pile is presented. A second analytical formula for determining the effective pile length of a soil-cement column is obtained and an example shows that the calculated and measured results are in quite good agreement.

Jan 1, 2002

By Walter G. Brusey

This paper describes a comprehensive pile test program conducted at John F. Kennedy International Airport (JFKIA) to evaluate pile types and design capacities ranging from 890 to 4450 KN (100 to 500 tons). Driven cased piles and drilled shafts, both standard construction and post-grouted after installation, were tested with platform loads extending to 8900 KN (1,000 tons). Alternate load test procedures were developed, extensive structural integrity testing and dynamic load tests were performed on selected shafts. A brief update is provided covering the application of results of the test program to pile selection for support of major structures incorporated in the on going redevelopment of JFKIA.

Jan 1, 2000

By Uwe Hess

For the Danish landworks for the coming fixed link between Denmark and Sweden across the Øresund the focus has been on the environmental aspects of the construction and operation of the facilities. This paper describes how the environmental objectives pertaining to the project have influenced the design and construction of one of the major elements of the Danish landworks, i.e. the tunnel in Sydhavnsgade and under Sydhavn Station. The chosen construction methods for the construction pit bracing and the groundwater lowering will be described along with the observed effects on the environment as shown by simulated or measured values for noise impact, settlements, pumped groundwater and extension of the drawdown cone.

Jan 1, 1996

By Anand J. Puppala

This paper provides information on various evaluation studies conducted to assess the CPT based interpretation methods. Salient findings from these evaluations are summarized. Additionally, a comprehensive evaluation study on both LCPC and European methods was performed on twenty-four driven piles selected from four different states. This evaluation showed that the LCPC method predictions are close to measured pile capacities. The European method provided good predictions for driven steel piles. Overall, both methods' predictions show high values of coefficients of variations, which are in agreement with other studies. Overestimation of driven concrete pile capacities is attributed to large estimations of unit point resistance. Suggestions to consider appropriate CPT based pile capacity interpretation methods are presented.

Jan 1, 2002

By James N. Mure

The paper describes the design development and construction of bored piles at Pindersfield Hospital, Wakefield, U.K. The piles were of monopile type. Monopile is the term used to describe piles which are constructed without pile caps so that the superstructure columns bear directly on the pile top. Pile geotechnical design was developed from the Site Investigation data and testing of two preliminary piles. Final design philosophy is described. Pile structural design was developed from the loadings applied by the superstructure, and the requirements, tolerances and limitations of monopile construction techniques. Construction was closely controlled in order to achieve a ?right first time? result. The conclusion gives a critique of the system and its value.

Jan 1, 2008

By Scott A. Walker, Gabriel J. Alcantar, Brian Zuckerman, Ramin Golesorkhi

"The new San Francisco 49ers Levi’s Stadium is part of the next generation of sporting facilities. Constructed in Santa Clara, Calif., the new structure has 68,500 open-air bowl seats and includes a 7- story tower housing more than 150 suites. The overall project includes the stadium structure, elevated open pedestrian walkways, commercial community space, three new pedestrian bridges and improvements to the adjacent light rail station. Sustainable design for the project includes a green roof, photovoltaic panel and a ground source geothermal system. Stadium-wide next-generation Wi-Fi capability is another feature. The design-build project team included HNTB (project architect), Magnusson Klemencic Associates (MKA, structural designer) and a joint venture of Turner Construction and Devcon Construction (TDJV, general contractor).During preconstruction, the 49ers’ original design team and the design-build team formed later worked together to facilitate communication and provide continuity. This helped to meet the project’s aggressive schedule. Working directly for the 49ers, with the design-build team, Treadwell & Rollo (T&R) served as the geotechnical engineer of record for the project from preliminary to final design and through construction. Although not contracted directly to TDJV, the stadium ownership encouraged direct interaction between T&R and TDJV and improved responsiveness to geotechnical issues during design and construction.Subsurface ConditionsThe new stadium lies within the Santa Clara Valley, a deep alluviumfilled basin resulting from historic movement on the active and potentially active strike-slip and thrust faults that bind the valley. The valley is filled with Holocene age (approximately 11,000 years old to present) alluvium, consisting of levee and basin deposits, with bedrock more than 750 ft (229 m) beneath existing ground surface. The stadium site is between two of the highly-active faults in California, the Hayward Fault 6.8 mi (11 km) northeast, and the San Andreas Fault about 11.8 mi (19 km) southwest."

Jan 1, 2014

By Patrick J. Hannigan, Seth Robertson, Rozbeh B. Moghaddam

The Top-Loaded Bi-Directional Test (―TLBT‖) and the conventional Bi-Directional Load Test (―BDLT‖) are full-scale static load test methods. In both methods, the test loads are applied bi-directionally to the deep foundation. The advantages of the conventional BDLT have been well established for cost efficient static load testing of deep foundations, particularly for large diameter, high-capacity drilled foundations. A conventional BDLT applies the bi-directional test loads using an embedded jack and bearing plates. The TLBT method also applies the bi-directional test load to embedded bearing plates but does so using reusable high-strength threaded bars attached to an above-grade hydraulic jack and load transfer assembly. The new TLBT method is well suited for load testing shafts of a moderate diameter, length, and nominal resistance or ultimate load. TLBT advantages include economic considerations resulting from the method’s reusable load application components and constructability considerations as it readily accommodates a center concrete tremie pipe or pump line location. This paper presents comparison results from full-scale load tests performed using both bi-directional load testing methods. Adjacent 3-foot diameter by 30-foot long BDLT and TLBT shafts were tested. Details regarding subsurface conditions and test shaft construction are included for the comparison of the TLBT and BDLT results. Corresponding test data and analyses for both test shafts are presented and discussed in detail. The BDLT shaft had a maximum uni-directional load of 240 kips at upper and lower bearing plate displacements of 0.5 and -3.8 inches, respectively. The TLBT had a maximum uni-directional load of 300 kips at upper and lower bearing plate displacements of 1.0 and -5.9 inches, respectively. These results as well as the load-transfer behavior and equivalent top loading curve results from the adjacent BDLT and TLBT drilled shafts are discussed. The paper also discusses the strain gage instrumentation on the TLBT load application bars and on the embedded bearing plates.

Oct 1, 2022

By Michael Frawley, Deana Ruud, Jessica Turner

Technology is allowing for new ways to mitigate risk associated with subsurface exploration and unanticipated subsurface conditions during construction. Unanticipated subsurface conditions have the potential to force delays and cost overruns on even the best-managed and well-executed projects. For more than a century, geotechnical professionals have documented the location and conditions encountered in hundreds of thousands of subsurface borings. Utilizing processes for compiling and managing data, owners can streamline site selection and receive access to a conceptual geotechnical model before field exploration takes place. Digitizing historical subsurface information allows for creation of an interactive, web-based platform combining publicly available information and culminating with the opinion of a local, experienced geotechnical engineer. This connectivity aids in the reduction of risks associated with unknown conditions on prospective project sites. Through this conceptual project study, we demonstrate how a project owner would be able to use a comprehensive desktop study to review the expected conditions prior to making a purchasing decision. Following the purchase, the expected conditions would be confirmed through traditional methods, confirming potentially problematic site conditions and the associated risks. INTRODUCTION Preliminary project planning is often based on assumptions made by the design team with regards to site suitability. After due diligence, site development is traditionally initiated by the owner or the owner’s representative when engaging a geotechnical engineer to perform a thorough subsurface exploration at a site. The data generated by the geotechnical engineer’s analysis of the site is required to design foundations, pavements and earth retaining structures and move the project from concept into design. This necessary, subsurface exploration can be time consuming, intrusive, and require significant resources, often when resources during construction seasons when resources are most limited. By leveraging historical data generated from previous subsurface exploration, a more thorough analysis of project risk can be developed prior to mobilizing a drill rig. Ultimately, preliminary budgets and designs are more accurate and geotechnical field exploration is more strategic. The geotechnical engineer’s role transforms from raw exploration and analysis to confirmation of anticipated conditions.

Jan 1, 2019

By Scott A. Walker, Roberto A. Lopez, Lori A. Simpson, David A. Shook

500 Folsom Street is part of the new Transbay neighborhood in San Francisco, which is being redeveloped after the 1989 Loma Prieta Earthquake damaged a freeway viaduct; removal of the viaduct created parcels of land available for development. The development consists of a 42-story residential tower with a six-level basement. The slender, core-only structure was designed using performance-based seismic design. Subsurface conditions include undocumented fill, Dune sand, marsh deposits, sand, and clay, all overlying sloping bedrock of the Franciscan Formation. The building is supported on a 10-foot-thick mat foundation approximately 62 to 72 feet below street grades; clay, sand, and bedrock are all present at mat subgrade. Under a portion of the mat, sand susceptible to liquefaction was present. The variable subgrade conditions and potential for ground failure, along with the depth of mat subgrade below street grade, created a challenge for the design and construction team to solve. The ground below mat subgrade needed to be improved to mitigate the liquefaction potential and provide more uniform support. The areal extent and depth of ground improvement necessary to support the mat with an acceptable amount of deformation was determined. Settlement was analyzed and subgrade moduli were provided for design of the mat, with multiple iterations performed to converge between the geotechnical and structural models. Based on the project schedule and logistics, it was beneficial to work from street grade to improve the ground. In order to target the depths below the mat and minimize wasted effort and materials within the depth of excavation, grids of jet grouting were determined to be the most economical ground improvement method; however, it was challenging to install the columns from 65 feet above the top of the target zone. During installation, QA/QC was performed to check that the jet-grouted columns were installed to the design depth and diameter and developed the design strength.

Jan 1, 2018

By Martin D. Larisch, Ronald Damen

The design and construction of temporary working platforms for cranes and piling rigs is a high-risk activity. It requires the careful selection of the appropriate input parameters to obtain the correct load cases, as well as the application of robust and reliable design methods to assess the required thickness and stiffness of the working platform. The document introduces some of the most common and most relevant guidelines for working platform design which are currently used in Australia and New Zealand. The authors will also discuss the basic assumptions and considerations about load transfer from construction plant, debate ground risk, compare the applicability of different design methods for various ground conditions and suggest some common verification methods for working platform certification.

May 1, 2022

By A. Boominathan

The behaviour of single piles under lateral dynamic loading is very critical and the study is still a current field of research since 1950's. Though many methods have been developed analytically to estimate the dynamic lateral stiffness, very limited dynamic testing on full scale piles were carried out to study the response of piles under lateral dynamic loading. Hence, field lateral dynamic vibration tests are conducted on driven precast concrete square pile of 400mm size and driven cast in-situ concrete piles of 400mm and 500 mm diameter at a petrochemical complexes site at Haldia (India). The results of steady state and free vibrations tests are discussed herein and compared with the response of the piles estimated from PILAY.

Jan 1, 2002

By S. Hardy

The paper describes state of the art non-linear analyses of the pile groups that were employed during the raising of the 133m high triumphal arch which forms the centre piece of the new Wembley stadium in North London. The deformation behaviour of these piles groups was critical during the lifting process, due to the slendemess of the arch structure. The issue was made more critical by the high profile nature of the project. The results of Class A (Lambe (1973)) predictions of the pile group movements are compared with observed displacements and rotations which were accurately measured on site. To illustrate the importance of soil non-linearity on pile group behaviour, comparison is also made with pile group analyses which assume a linear soil stiffness.

Jan 1, 2006

By Alain E. Holeyman

After scoping out the objectives of this general report, the report reviews the three assigned main themes addressed by the papers submitted to the session: pile monitoring, testing, and data processing. It focuses on later developments and on issues requiring clarification, thereby identifying topics for potential discussion. Pile Monitoring does not bring much novelty, except for the integration of IT on construction sites. As far as testing, new developments focus on internal pile loading procedures while more confidence is being gained with dynamic and kinematic load tests. Significant advances are noted in the interpretation of data, where variability of results are coped with, loading rate effects are being better addressed, and more routine use of Finite element analyses are observed. Several many older problems remain while new issues emerge from more recent technologies and approaches.

Jan 1, 2006

By Timothy D. Stark

Jet grouting has increasingly become a ground improvement technology used to address seepage concerns and provide strength improvement to soils underlying dams. The technique of jet grouting uses high pressure/volume jet fluids to erode existing soil, evacuate some or most of the soil, and mix the remaining cuttings with cement slurry to form soilcrete. While considered a useful technology, this paper discusses some of the problems that can develop while jet grouting in or below a dam with an operational reservoir and seepage condition. Jet grouting experience at Tuttle Creek Dam indicates concerns with respect to ground fracture; spoil return, column diameter consistency, and homogeneity of resulting soilcrete. Recommendations are presented to increase monitoring of downhole parameters during jet grouting to better understand the downhole pressures and soil response during jet grouting.

Jan 1, 2012

By Walter E. Vanderpool

Type 1B micropiles (Bruce and Juran, 1997) can be installed rapidly and efficiently. During an 85-day period, 536 micropiles were installed to depths of 61 meters within a site 41 meters by 43 meters. Their performance, as measured by load test, varied even where the materials, construction procedure, and installation technique were closely monitored and controlled. The variation in displacement, as measured by the standard deviation, exceeded 50 percent of the mean test-load displacement for all loads up to the maximum load applied (2670 kN). This study provides a statistical basis to predict variability with respect to the construction method, micropile materials, and installation technique. The variability of displacement at all test loads is a fundamental characteristic of this type of drilled deep foundation system.

Jan 1, 2002

By Jeffery L. Ottesen

Early construction delays can jeopardize timely completion of subsequent work. As an early construction activity, and due to many unforeseen issues, deep foundation work inherently bears great potential for impacting the critical path of a planned construction schedule. This article describes two construction projects where delays related to deep foundation work forced the Contractor to consider various schedule recovery alternatives to mitigate those delays. Specifically, deep foundations on Vancouver BC's Millennium SkyTrain light rail extension and on a Mill Facility in the United States are discussed. This article cites examples of permitting delays, alleged design changes, differing subsurface conditions and changed construction methodology, the effect each problem had on the project, the mitigation means implemented by the Contractor to minimize adverse impacts of the problem, and Lessons Learned for each scenario.

Jan 1, 2002

By Matthew Janes

The RC Harris Filtration Plant, which treats the majority of the fresh water for over 2.5 million Torontonians, is a Canadian Architectural Heritage site demonstrating a classic example of Art Deco Architecture. The facility is undergoing an expansion to install an underground sludge treatment capability. Perched atop a bluff on the North shore of Lake Ontario the structure enjoys a commanding presence on the Lake Ontario shoreline. A series of underground tanks were proposed for the hillside below the structure, which when covered would preserve the building?s architectural presence. However, the plan required two, stepped excavations 12 m and 10m deep into compact, wet sands over stiff clays and clayey silts. Concerns regarding the original structure influenced designers to set the lateral deflection limit for the front footing of the existing structure at 4 mm, (0.03% excavation depth). The design-build team indicated at the time of tender that the movement criteria was unattainable using the tender design. Analysis indicated installation effects and overall elastic movement of the soil mass beneath the building would result in movements of 7 to 9 mm at the structure. Through extensive FLAC analysis and a novel construction geometry the design-build team crafted an alternative that produced significant savings over the original concept. Based upon the analysis the design-build team negotiated a new deflection criteria dictating a maximum of 2.0 mm of movement across the critical expansion joint between the Filter Building front footing and the tank slab beyond. The contractor invested in additional pre tender soils investigation to support the refined design process. The FLAC analyses indicated the Filter Building movements would be elastic and distributed up to 50 m back beneath the front footing of the structure. An extensive precision monitoring program proved construction related movements of 6 to 10 mm horizontal at the front footing. Extensometers placed at two locations over the critical interior tank expansion joint showed no measurable movements. The overall monitoring program, including inclinometers, tilt meters, tie back extensometers (smart cables) and tie back load cells indicated a good match between recorded movements and loads and those predicted by FLAC Analysis.

Jan 1, 2006

Port Gaspé is located on the back side of Gaspé bay and is protected by a natural sand barrier with a length of 2,5 km, from which it got its name, Gaspé Sandy Beach (1). Since 1904 the Gaspé region had a deep water wharf, initially very different, in fact, from the one existing just before the recent reconstruction (2). This wharf with a length of 228 m and a width of 23 m was build of timber cribs. The outside walls of these cribs had been doubled with a wooden wall, creosote impregnated to provide resistance to decay and to the attack of marine organisms (limnorias) (3). Fifteen years ago the upper part of the wood construction had to be removed, because of progressing rottenness and was replaced by an L-shaped reinforced concrete structure (4).

Jan 1, 1987

By James Green

It has often been said that the best contracts written are by people who are suspicious of each other. The Spanish philosopher, Ortega y Gasset, said: "Every contract is an Act of Distrust." The arena for dispute settlement outside of the courts is increasing day by day - contracts, especially construction and civil engineering contracts, are written containing arbitration clauses for settling disputes - the very drafting of standard forms of contract, do in some instances by their very construction, create an ambiguity as to intent and provide a breeding ground for dispute. I come from a land far across the sea - the most southern land before the South Pole. Being a young country, 150 years old, we are still progressing - being far removed from the trouble free zones of the world and nuclear free we enjoy a lifestyle second to none.

Jan 1, 1987