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"Boston’s Central Artery passes beneath nine active railroad tracks carrying commuter and Amtrak trains into South Station, the City's busiest rail terminal. These railroad operations had to remain in service throughout the construction of the “Big Dig”. The solution was to jack the tunnel under the tracks, rather than build the tunnel by more conventional means.Jacking of utility pipes is fairly common, but jacking boxes as big as a highway had never been done in North America, until the Big Dig came along.Soil freezing was decided upon as a means of stabilizing the soil under the tracks. This allows the tunnels to be jacked into place without soil caving when the soil is excavated at the leading face of the advancing tunnel boxes. Hundreds of pipes were driven into the ground between the tracks. Inside the steel pipes were smaller plastic pipes. A freezing plant near the railroad tracks pumped refrigerated brine into the inner plastic pipes. The brine ran out the bottom of the inner pipe, flowed up to the top inside the outer pipe, and was re-circulated to the freezing plant and back again into the ground. Over several weeks the circulating brine drew the heat out of the soil little by little, and froze the ground outward from the pipes. Soil FreezingThe plan required the construction of jacking pits in which the tunnel boxes could be constructed, and from which they could be jacked forward to their final locations, as described in the accompanying article. Once the jacking pit was built and the tunnel box constructed inside the pit, crews made an opening in the headwall of the pit to allow passage of the tunnel sections, excavated about three feet of the frozen soil, pushed the tunnel box ahead, and repeated the procedure again and again."

Jan 1, 2003

By Jacob A. Jordan, Rachel M. Garrett, W. Robert Thompson III, James C. Pegues

"Environmental control structures for an existing fossil-fuel power generating plant near Pascagoula, Mississippi faced several design and construction challenges due to space limitations. Conceptual design calculations indicated drilled shaft foundations would likely be needed to accommodate the higher lateral and compressive loads expected under some structures. A maximum drilled shaft diameter of 60-in was preferred due to various space constraints. Smaller diameter drilled shafts were deemed acceptable under structures with more moderate loading conditions. Furthermore, augercast piles were considered where lateral loading was not a governing design criterion.A series of SPT borings and CPT soundings revealed a subsurface profile consisting of soft to firm clays to depths of about 25 feet, underlain by fine to coarse sands. The apparent relative density of the sands was loose just below the clay, with increasing density noted with an increase in depth.Analysis of conventional drilled shafts indicated needed capacities could not be achieved unless shaft lengths exceeded 100 feet. Post-grouted drilled shafts were therefore evaluated to decrease shaft lengths by taking advantage of increased base capacity. Analyses showed the higher predicted capacities needed for some structures could be achieved with this approach. Final design for the project incorporated 90-ft long, 60-in diameter post-grouted drilled shafts; 60-ft long, 48-in diameter post-grouted drilled shafts; and 60-ft long, 48-in diameter conventional shafts. Both post-grouted and conventional trial shafts were installed as part of the detailed design phase of the project. Each trial shaft included CSL integrity testing and Osterberg-cell bi-directional load testing. Load test results revealed that additional base capacity was, in fact, achieved through the post grouting process. The 60-in diameter post-grouted production shafts and the 48-in diameter conventional production shafts have been installed at the site, with the project that would utilize the 48-in diameter post-grouted shafts deferred at this time."

Jan 1, 2015

By Lucian L. Bogdan

"SummaryActive loaded strand anchors are often used for slope stabilization, retaining walls or tiedown anchors. Normally, strands are tensioned against the structure and wedges are locked inside the anchorages at a certain lock-off load. During the life of the structure, anchors can receive additional loading during a surcharge, seismic event or other activity on the structure.In order to have a reliable ground anchor system, the strand must not slip through the anchorage wedges during its service life. Strand slippage has been reported during lock-off, when dirty wedge plates and wedges have been used. Low lock-off loads are believed to contribute to strand slippage too. Since the initial lock-off load for a ground anchor is usually lower than the lock-load for an equivalent capacity tendon in other types of post-tensioning construction, there is a concern that strand slippage may occur if the load on the anchor increases above the initial lock-off load.Corrosion protection grout, placed after the anchor is locked off, fills the pocket and surrounds the strand and wedges. Some anchor installers believe that the grout will prevent the anchorage from developing additional capacity if the load increases above the initial lock-off load.The load-carrying capacity of an anchorage depends on several factors. Most important are: initial applied load, anchorage geometry, friction between wedge-anchorage-strand and condition of the contact surfaces.The ADSC Anchored Earth Retention Committee considers that the industry should know how wedges behave once the permanent strand anchors are stressed and grouted inside the transition pipe, between wedges and inside the grout cap."

Jan 1, 2005

By Grischa Dette, Thomas Schröder, Holger Merski

For the construction of the tunnel for the new Berlin S21 light rail line, a construction pit had to be built below the crossing B 96 federal road. For this purpose, the construction pit M’ has been built beforehand as a preliminary structure for the later S21 Berlin. A crucial element of this structure is a 2.50 m deep reinforced concrete deck slab which carries the B 96. During the later construction of the S21, it became clear that the existing preliminary structure could not be used without major modifications. Consequently, the construction pit design was gradually upgraded – still with the aim of retaining the basic concept of a trough structure with a jet-grouting cut-off. As construction progressed, for reasons of stability it became necessary to develop a fundamentally new concept with an underwater concrete base replacing the jet-grouting cutoff. This paper describes the planning and construction of a cut-and-cover structure with an underwater concrete base – a layout that brings with it the difficult task of underwater excavation and concrete placing without direct accessibility from above. Special emphasis is placed on describing the innovative approaches in connection with a remotely controlled underwater dredger from the Norwegian offshore industry for excavation works. Furthermore, the sophisticated underwater technologies for concrete placing in the confined surroundings are described.

May 1, 2022

By Christian Hoyme, Jochen Maurer, Hans Regler

Up to today, it has been very difficult to obtain qualitative and quantitative information about the status and production process of a construction site. It is becoming more and more important to be able to analyze this process so as to notice bottlenecks and interruptions on the site early on. The high costs of each shift in special foundation industry mean that making the wrong decision and/or interruptions can put the financial result at risk. Previously, keeping reliable data meant manual process documentation. This was done either by an additional staff member (incurring high additional costs for training, education, etc.) or by the equipment operators. The latter is critical, because they have to initiate every process step change, leaving no time to log data separately. Studies have shown that there are considerable deviations from the actual process steps. In this paper, a seamless, automated method will be introduced to analyze the construction process. This method recognizes each process step from the equipment data. The main purpose of the data recorded by the piling rig is the need of quality reports and now basis for the presented analysis. Here, a method was successfully transferred from theoretical computer science (compiler construction field) to find application for process recognition. Because the execution of works in special foundation construction can always be defined sequentially and therefore also practiced sequentially, recognition can occur step-by-step. Our method always recognizes the next step, so it does not have to monitor as much data at the same time. Individual trigger points are easier to define. Unlike solutions that are based on a global approach and allocate suitable process steps to data patterns, thereby also creating gaps, the presented method is always seamless. Furthermore, this method can be applied regardless of time or location provided that the necessary machine data is available, which is normally the case with production data logging. This means that construction sites even from the past can also be analyzed and the results used for comparisons. The first results from the analysis of a complete continuous flight augering (CFA piles) installation process of a construction site will be presented.

Sep 8, 2021

By Mitsuhiro Shibazki

I can't answer that question but I am looking at Andy, my co-author, and he says we didn't measure it. No movement. If I understand it correctly, how do we handle lateral forces in shear? The main columns were designed as pin connections so there wasn't a moment in the shear between the pile cap and the columns the steel reinforcing was used to resist that. I am not aware of how we would have installed those, it is possible to try and submerge them all if the jet grout is still fluid. They were higher than design. You are correct.

Feb 10, 2003

By P. Middendorp, Gerald E. H. Verbeek

"INTRODUCTIONStatic Load Testing (SLT) is generally considered the pile testing method that provides the de-facto answers regarding pile capacity and load-deflection behavior. However, as this testing method is time consuming and costly, alternative pile testing methods are applied, such as High-Strain Dynamic Testing (HSDT), commonly referred to as Dynamic Load Testing (DLT), and Rapid Load Testing (RLT), which includes Statnamic Testing (STN) and the Fundex Pile Load Tester (PLT). Extensive descriptions of these pile testing methods as well as comparisons of the results from these two methods have been widely published, but little is written on the choice between HSDT and RLT. This article will address this issue for concrete piles by discussing five different aspects that should be considered when making a choice between HSDT and RLT for either cast-in-situ piles or precast driven piles. TIMINGThe timing of the pile load test is independent of the testing method. For cast-in-situ piles load testing is performed some time after the pile has been installed (to allow the pile to obtain the compressive strength required to withstand the test load), while for precast driven piles load testing is performed after a so-called set-up period following pile installation (to allow the soil to recover from driving induced disturbances and, at least in most cases,regain strength).In other words, the timing of the test does not affect the choice of the testing method.ACCURACY OF THE APPLIED LOADWhen a pile is tested by RLT the applied load is measured by a calibrated load cell placed on the pile head, just as it would be during SLT. This means that the error in the applied load value is less than 0.1% of the maximum range of the load cell.However, when a pile is tested by HSDT the load is calculated from the measured strains, which means that the outcome is dependent on the pile material properties. In this case the applied load (F) on the pile head is calculated by multiplying the measured strain (?) with either the calculated or estimated elastic modulus of concrete (E) and the pile cross section (A).The elastic modulus is generally back calculated from the (average) stress wave velocity (c), which in turn is derived from the reflection time (T) it takes for a stress wave to travel over the pile length (L) from the pile head to the pile toe and back to the pile head."

Jan 1, 2006

"After the non-destructive testing is completed, the data must be compiled, evaluated, and interpreted. During this process, the data may indicate that there is an anomaly warranting further investigation, which may eventually be determined to be a flaw or defect. The definitions of an anomaly, flaw, and defect can be described as follows (after Amir, 2002):Anomaly - Any irregular feature identified in the NDT graphic results. An anomaly may be due to the testing instrumentation (such as noise), to the means used to perform the test (e.g. access tube debonding in CSL) or to the shaft itself. It is the responsibility of the NDT practitioner to gather and analyze all relevant data and try to resolve every anomaly before it is declared a flaw or defect.Flaw - Any deviation from the planned shape, size and/or material of the shaft.Defect - A flaw that, because of either size or location, may detract from the shaft’s intended performance or durability. The geotechnical engineer and the structural engineer are jointly responsible to decide which flaw comprises a defect.This section describes the process of evaluating the data, determining if an anomaly exists, and if so, deciding whether the anomaly is actually a flaw or a defect. If the anomaly is determined to be a defect, its effect on the performance of the shaft must be evaluated, and if necessary, the can be re-engineered, repaired, or replaced."

Jan 1, 2004

By Kevin Cunningham

"Litigation resulting from neighboring structures with settlement and/or lateral movement or improper pile design and faulty soils engineering analysis, are a multi-faceted opportunity for law firms. These types of claim scenarios are an attorney’s dream, and can obliterate a Deep Foundation Contractors profit and more importantly, can be avoided with a progressive approach to risk management in design and project management.The following (4) case studies will be examined and dissected to discern certain lessons learned for risk management solutions to avoid these deep foundation related challenges in the future.1) Pipe Flotation – Soil Conditions Not Anticipated in Specifications or Contract2) Easement Encroachment – Easement Dimensions Not Recognized Until Completion of Project3) Subjacent Lateral Support – Neighboring Structure Wooden Pile Unprotected Causing Structure to Settle4) Improper Pile Placement - Construction & Design Caused Retail Store to SettleSpecific Deep Foundation project challenges involving: buoyancy calculations regarding subsurface soil characteristics, design factors taking existing subsurface sewer line easements into account, structural instability as result of excavation causing exposure/heavy rainfall to existing wooden piles supporting adjoining building and improper pile location resulting from faulty pile design will be described with risk management recommendations to avoid these challenges in the future.From the very start of construction on any project deep foundation and excavating work poses numerous engineering and technical challenges for developers, contractors and engineers. Dealing with changing or hidden conditions is one of the most difficult challenges facing any contractor or engineer on a project. Relying on incomplete or inaccurate engineering reports is another common problem. Other challenges include dealing with technical errors or oversights that are deeply embedded in the project specifications or bid process.No matter what is the origin of the problem or how it manifests, deep foundation contractors, design professionals and engineers should be ever-mindful of good risk management practices that can prevent serious disputes that can result in costly litigation."

Jan 1, 2015

By Wang Lushuang

This thesis is devoted to the research of the interaction between pile and foundation soil by boundary element method (BEM for short). The interaction is simulated by the interaction between two different elastic mediums. The foundation soil is simulated by the two-dimensional elastic half-plane, and the pile by the two-dimensional elastic finite plane. Therefore, the calculating models made by the paper's author would come more closed to the actual conditions. The elastic behaviour of the interaction between pile and soil, and the whole course of pile ultimate load are analysed in the thesis, and the relevant applied computer programs "BEME", "BEMPA" are designed by the paper's author. The bearing power of single pile can be worked out by the program "BEMPA", it has compared with staic loading tests of pile, and the results are in conformity to actual conditions. So it can be drawn that the BEM for studying on interaction between pile and foundation soil made in the thesis is more simple, more precise and more practical in actual project.

Jan 1, 1991

By John A. Egan, Nathaniel Wagner, Micaela Largent, Jonathan P. Stewart, Debra Murphy, Jeremy Butkovich

The Millennium Tower is a 58-story reinforced concrete building that was constructed in San Francisco, California between 2005 and 2009. The Tower is founded on an embedded pile supported mat with pile tips bearing in dense marine deposits that overlie an over-consolidated marine clay layer known locally as Old Bay Clay. This clay layer experienced stress increases from Tower self-weight and from multiple episodes of de-watering between 2006 and 2018 at the Tower site and neighboring sites. Settlements of the Tower foundation have been measured since 2006 and lateral deflections of the Tower have been inferred and measured since 2009. Available information on this case history include geotechnical site conditions and data from a monitoring program that tracked foundation settlements, Tower tilt, groundwater levels at the Tower site, and ground inclinations over time. This presentation will discuss the ground deformation mechanisms that caused the observed movements, the degree to which the movements can be predicted, and lessons from this case history for the design of deep foundations for tall buildings in San Francisco and geologically similar regions.

Sep 8, 2021

By Douglas Heenan

The fracture orientations were inferred based on theory and previous experience. The fracture pattern was not monitored during the project. Grout volume was recorded at each sleeve port and real time movement monitoring of the building foundation was performed.

Feb 10, 2003

By Allen Cadden

The type of soil we had was a silty fine sand. It had been placed by hydraulic methods in 1904 so it was quite clean I would say less than 10% silt the rest of it was very loose sand. That I'm not certain, I've only done it on sandy soils but it would stand to reason that some sort of a number should apply because you are measuring the amount of work that you are doing to it so if the soil is fairly consistent over the site it should be able to generalize from there but I don't know for a fact that it works. Well, verifying to ourselves that this method actually worked because we weren't certain at first when we were doing it so then we would develop the numbers and then check the results.

Feb 10, 2003

By Sherif Elfass, Gary Norris

Bi-directional load testing of drilled shafts has been widely adopted as a means to evaluate their load carrying capacity. However, in order to reach failure, most of these tests are carried out on sacrificial shafts using expensive sacrificial elements such as hydraulic jacks. A proposed low-cost bi-directional testing technique is discussed. It mechanically loads the end bearing soil below a drilled shaft, against its side shear resistance. The technique was originally established as an alternative to post-grouting to reliably account for the forfeited end bearing resistance. However, since it loads the shaft in a manner similar to conventional bi-directional tests, it can be used to not only load test sacrificial shafts, but production shafts as well. Furthermore, unlike conventional bi-directional load tests, the load is applied through surface jacks. These jacks, along with other load test components, are movable and can be reused to load test all the shafts of the project thus presenting an economic benefit. The concept of this technique has received favorable feedback from a few consulted departments of transportation, and while promising, has not been field tested to date. A U.S. patent was issued for the tip loading module and the loading technique described.

Sep 8, 2021

By Lok M. Sharma

Development of brownfields is of great interest in these days. Such fields are not easily adaptable for foundations of structures. The uncertainties in ground behavior present challenges of unpredictable subsidence that could be detrimental to the build up facility. A desalination plant had to be located along the seashore, close to the needy population and the existing water supply infrastructure. The available site had been developed as a recreational park area over a dumped construction demolition debris landfill along the coastline. To construct a desalination plant comprised primarily of large concrete basin tanks on slab, founded on the debris fill had its challenges. A ground improvement system in the form of vibro replacement stone columns was designed and constructed. Approximately 5,000 stone columns were installed across the site. This paper describes the analysis process, the design, field load testing, and installation of stone columns. Difficulties during construction and monitoring aspects are briefly described. The plant started operations in the summer of 2008 and to date has performed satisfactorily. When properly designed, the development of brownfields is achievable at other sites.

Jan 1, 2009

By Todd Nottingham

Channel deepening of major ports is challenging designers to explore innovative solutions to ensure stability of bulkheads, such as for the Oakland Inner Harbor. This particular challenge was met with the use of the SPIN FIN® Tension Pile for restraint of an HZ combination wall along the Oakland Inner Harbor Shoreline in Oakland, California. A SPIN FIN pile is a pipe pile with welded plates at the pile tip that increase pile capacity. A brief history of the project will be provided as well as results of pile load tension tests, pile strain gauge, and wall deflection under construction loads. Tension pile load deflection results will be discussed with recommendations toward establishing deflection-based ultimate load criteria. A discussion of predicted wall loads and field observed wall loads will be provided.

Jan 1, 2008

By Nathan A. Ingraffea

The use of steel sheet pile walls and drilled shaft foundation elements to enable up-down construction methods has been used successfully on recent high-rise structures with multi-story below grade parking. The John Ross Tower and The 3720 Tower in Portland, Oregon each make use of this system and are discussed in-depth. Up-Down construction involves the simultaneous construction of the building levels above and below grade instead of the standard construction technique of excavating and shoring the below grade construction before being able to build upward from the base of the excavation. Advantages of the up-down system include a shortened overall construction schedule, permanent basement walls that double as the temporary shoring walls, elimination of the typical continuous wall footing or grade beam at the building perimeter, increased use of recycled material (steel) while maintaining an overall decrease in total materials, elimination of wall forming costs, decreases in forming costs for slabs, decreases in waterproofing costs for walls and elimination of pile caps and/or footings for the building columns. Lessons learned during the construction of both buildings include the need for more extensive geotechnical boring information, descriptive sheet pile and drilled shaft specifications, a clear understanding from the design team on finished appearance of sheet pile and shafts, and careful consideration of the connection between both slabs and the sheet pile wall and slabs and drilled shafts.

Jan 1, 2008

By Yoshinori Kurumada, Masaya Watanabe, Kenji Sasa

"The Port of Yokohama is strengthening its international competitiveness as a strategic container port in order to respond appropriately to global exchange and shipping demands. Thus, the Minami Honmoku main Pier is currently being developed. The high-standard container terminals MC-1 and MC-2 have already started their service, and the development of the container terminals MC-3 and MC-4 is currently in progress.Because the South Honmoku Pier plays an important role in waste disposal management of Yokohama, a final waste disposal site (controlled final landfill site) is being developed in Block 5 to provide long-term and stable reception of waste that will be generated in the city. For this project, a revetment with water-blocking properties and an extension approximately 1.7 km in length is being built in order to prevent water from leaking from the disposal site. The base part of the revetment will be subjected to foundation improvement using the Cement Deep Mixing (CDM) method in order to secure water shielding of the soft sediment underneath the water, prevent slipping of the seawall, reduce the amount of subsidence, and increase the foundation support force.This report presents a preliminary study on using CDM on reclaimed soil and the construction process of the development project of the disposal site in Block 5 of the Minami Honmoku Pier, which has been underway since 2007.ABOUT MINAMI HONMOKU PIERThe development of the Minami Honmoku Pier started in 1990. It was designed to develop high-standard berths with greater water depths in order to handle the increasing volume of foreign container cargo and growing size of vessels. Figure 1 shows the layout of Minami Honmoku Pier. In April 2001, the Phase 1 (MC-1 and MC-2) began services. This is the newest pier in Port of Yokohama.This pier has one of Japan’s largest terminal areas (40 ha) and is equipped with 22 row-type mega gantry cranes capable of handling the newest ultralarge container ships. The pier has a quay with a water depth of 16 m, which is the first in Japan. The pier is equipped with advanced facilities and equipment to let Port of Yokohama be internationally competitive and function as an international commercial hub. An innovative system for high-efficiency transport is currently being introduced; it includes the installation of waiting vehicle lanes and a reservation-based loading and unloading system.Since the fiscal year 2007, a new container terminal (MC-3) with a -20m deep quay capable of handling the increased size of container ships and the diversification of port logistics has been under construction and is nearly completed."

Jan 1, 2015

By Brett K. Mainer

In the summer and fall of 2007, Drill Tech Drilling and Shoring, Inc. designed and built three 24-foot inside diameter shafts in Northern California using soil mix panels for support. The soil mixing was performed using the Bauer Cutter Soil Mix (CSM) method, by which rectangular soil mix panels up to 71 feet deep were arranged in an overlapping manner to form a 24-foot inside diameter circle. The shafts were then excavated to depths up to 51 feet. One of the shafts was a test shaft and used only the soil mix panels for support. The other two shafts were located immediately adjacent to the Mokelumne River and were used as access pits for a microtunnel drive under the river. These two shafts had wide flange beams embedded in the panels and were supported with several levels of ring steel placed during excavation. This project was the first use of the Bauer CSM method in the United States. The CSM method has been used extensively in Europe and Asia, but never for this application and never with this high a loading criteria due to water head and microtunnel reaction forces. Soil conditions at the river crossing shafts consisted of sands, gravels, and cobbles over top of sandstone and conglomerate bedrock ranging in strength up to 5,000 psi. Groundwater was within several feet of the surface. The shafts were successfully completed between October 2007 and January 2008, and the microtunnel was successfully completed in February 2008. This paper provides discussion regarding selection of the shoring type, structural design, the soil mixing method, and the mix designs. Shaft construction, shaft performance, and the capabilities of the CSM equipment are presented.

Jan 1, 2008

By Jon E. Bischoff

Construction of a secondary clarifier on the banks of Rainy River, Northern Minnesota, required the driving of H-piles 14HP102 to a sloping, very strong bedrock through thick deposits of soft and medium stiff soils. Pile toe protection, APF Hardbite HP 77750, was specified to prevent damage to the pile toe and to enable the pile toe to bite into the bedrock surface. The toe protection worked well for bedrock sloping less than 2H:1V. However, where the bedrock was steeper, the piles experienced damage and failed to reach bearing. In most cases, the also the replacement pile failed. Pile Driving Analyzer measurements showed that on encountering the bedrock, the pile toe reflection, which at first was sound, deteriorated indicating pile toe damage. Extraction for visual inspection showed that the failed piles were bent and had deformed pile shoes. In areas of steeply sloping bedrock and for replacement piles, an alternative shoe, the Scanpile Herkules rock shoe, was employed. This pile shoe proved to be able to secure the pile toe into the rock and to eliminate the problem. The costs of the Herkules rock shoe considering price, shipping, and attaching, were about equal with the Hardbite shoe.

Jan 1, 1993