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By Pancho J. Garza, Keith H. Dahlen, Chris A. Labye

"Design for reconstruction of the East Flagstaff traffic interchange project located in Flagstaff, Arizona posed particular challenges. The proposed design included construction of a nearly 50-foot tall mechanically stabilized earth (MSE) wall given rightof- way constraints and soft subgrade soils. The tight right-of-way, approximately 15 feet in certain locations, adjacent to existing structures limited the number of viable remedial alternatives to provide grade separation at the proposed bridge abutment without significant settlement. Preliminary analyses indicated the existing subgrade soils - consisting primarily of relatively soft silts and clays with decomposed pumice - would settle approximately 12 to 14 inches resulting in unacceptable wall deformation. Stone columns placed via vibratory methods (vibro-replacement) consisting of circular excavations which penetrate to firm bearing soils and which are filled with crushed stone were selected to densify the existing subgrade soils. The implemented mitigation measures helped limit settlement to less than one inch and allow for successful construction of the project. The project history - including site constraints, subsurface conditions, evaluation of remedial alternatives, stone columns methodology, and effectiveness of ground improvements - will be discussed.IntroductionThis paper describes the subsurface investigation performed for the reconstruction of the Business Route 40 (B-40) (Country Club Drive) and United States (US) 89 Traffic Interchange (TI) located within the city limits of Flagstaff, Arizona. This project is currently referred to as the East Flagstaff TI. The Project Site Vicinity Map is shown below.The former B-40/US 89 TI was considered ineffective in handling the current and projected volumes of traffic which transition from northbound (NB) B-40 to US 89 (both directions), as well as from southbound (SB) US 89 to SB B-40. The intent of the project was to reconstruct the TI to better accommodate projected traffic volumes. The project eliminated the existing ramps from both NB B-40 to SB and NB US 89. The new interchange includes a Tee intersection from B-40 to US 89. In order to accommodate this alignment, the profile of US 89 was raised several feet (on nearly the same as existing horizontal alignment) to match the elevated profile of B-40. B-40 was shifted just west of its current alignment to accommodate construction of a new, wider bridge structure which spans over Industrial Drive, the Burlington Northern Santa Fe (BNSF) railway, and old Route 66. South of the new bridge, B-40 transitioned back to the existing alignment just north of the I-40/B-40 TI. Within the project limits, both US 89 and B-40 were widened to three travel lanes in each direction."

Jan 1, 2015

By Jochen Maurer, Dr. Christian Hoyme, Dr. Hans Regler

Currently, it is very difficult to obtain qualitative and quantitative information about the status and production process of a construction site. As a rule, companies depend on reports from on-site experts. There is no end-to-end digitalization due to the mobility of equipment and ever-changing locations. Equipment from different manufacturers, especially in special foundation engineering, is highly specialized. Any data collected by this equipment is recorded in proprietary formats and made available on the manufacturers' platforms. This exacerbates the situation, making simple analysis of performance indicators impossible. Most functions such as construction diaries, equipment utilization analyses, etc. are implemented only as standalone solutions. This does not allow for prompt visualization and intervention in critical process sequences because the construction site process is usually managed using a cost-based method. Furthermore, special foundation engineering requires a high level of expertise in an extremely wide range of construction processes. In this article, the results from a set of non-proprietary performance analysis tools are presented using numerous practical examples. Once a construction element is completed, the equipment data is immediately transferred to the platform using the latest cloud technology. Because the data is normalized, construction progress can be documented immediately, even for mixed equipment fleets. Bottlenecks can be immediately detected by visualizing the current performance of the production process, which is broken down into individual steps. Modern analyses of this equipment data improve quality, thereby providing better information about current performance. These sets of tools are essential for changing from the current monetary or cost-based method of process management to time- and bottleneck-oriented management. This makes it much easier to identify the critical path during projects. The article shows that processes can be documented and managed.

By Takefumi Takuma, Hiroyuki Nishimura, Shigeru Kambe

"Japan’s Great Tohoku Earthquake and the immediately following tsunami of March 11, 2011 killed more than fifteen thousand people and destroyed numerous buildings and infrastructures in the northeastern part of the country.In addition to reconstruction projects in the areas where the earthquake and tsunami hit, other seismically vulnerable regions in the country have started building new and more robust facilities as well as upgrading existing coastal structures so they will be able to cope with such deadly seismic and hydraulic force. This paper will highlight two different types of aseismic and anti-tsunami levee upgrades currently under construction on the coast of Kochi Prefecture, approximately 500 miles west of Tokyo. The first type is the installation of double sheet pile walls in existing seawalls. The second type is to drive tubular piles into existing levee structures for reinforcing them. Both sheet and tubular piles are being driven by the Press-in Piling Method without removing or compromising the function of the existing structures. 1. BACKGROUNDGreat Tohoku Earthquake of March 11, 2011 caused severe damage to many structures. ASCE’s survey of damaged coastal structures conducted immediately after the disaster by Ewing, et al. (2014) categorizes failure modes of the structures in the following manner.?Overtopping without structural failure.?Overtopping with structural damage or failure.?Wave uplift forces.?Movement of structure off foundation from sliding, rotation, or overtopping.?Impact loads.?Hydrostatic pressure.?Supercritical flows.?Scour.?Erosion.?Abutments end effects.?Subsidence."

Jan 1, 2017

By Lawrence F. Johnsen, Felix Ferrer, Dino Tomasetti, Cassandra A. Wetzel

"A 17 story building was constructed at the Brooklyn Navy Yard on a site with a long history of development. Most recently the site supported a dewatering well and craneway to service two adjacent drydocks. The subsurface conditions generally consist of the following strata and approximate depths: miscellaneous fill and debris to 20 ft., organic soils to 35 ft., liquefiable sand to 45 ft., varved clay to 65 ft., glacial till to 95 ft. and gneiss bedrock.Hollow core bar piles replaced 18 in. diameter caissons on a 1.67:1 basis. The resulting service loads on the hollow bar piles were 600 kips compression, 21 kips lateral, 180 kips tension and 450 inch-kips moment. The top 30 feet of the hollow bar was cased with a 16 in. x 0.375 in. Grade 50 steel pipe. The piles were socketed 6 feet into bedrock. An extensive load testing program confirmed the axial and lateral load capacities. The paper will also discuss some adjustments to the installation procedure based on the load test program.PROJECTThe hollow bar piles were installed to support a 95,000 sf footprint, 17-story office building at the Brooklyn Navy Yard. The Brooklyn Navy Yard was first developed in the late 1700’s to build merchant vessels. The federal government purchased the old docks and adjoining 40 acres in 1801. The site was an active U. S. Naval Shipyard from 1806 to its decommissioning in 1966. At its peak in World War II it employed 70,000 people, 24 hours a day. Since 1966 the property has been converted to private manufacturing and commercial activity.The site is located between Dry Docks 2 and 3. The adjacent drydocks extend 40 to 43 feet below grade. The drydock walls are restrained by tierods extending back to deadman anchors. The site is also underlain by piles that were installed to support rail lines and a craneway. The building footprint also covered an 85 ft. wide, 70 ft. deep dewatering well which had a thick slab. The structural engineer for the project, ARUP, designed the building to span over the dewatering well.SUBSURFACE CONDITIONSIn September 2014, Langan Engineering conducted a geotechnical engineering study for the project. Figure 1 provides a subsurface profile through the long axis of the site. The general soil profile was very erratic but generally consisted of miscellaneous fill and debris to 20 ft., organic soils to 35 ft., liquefiable sand to 45 ft., varved clay to 65 ft., glacial till to 95 ft. and gneiss bedrock. The fill contained numerous obstructions from the over 200 years of site development. The organic soils were mostly very weak and compressible organic silt. The depths and thicknesses of the varved clay, and sand varied"

Jan 1, 2017

By Abid Adekunte

"Engineers and developers have witnessed the growing popularity of deep basement structures as components of urban commercial and residential developments. This is often attributed to inadequate surface parking facilities in urban centres and a somewhat popular belief that underground parking facilities improve both commercial and aesthetic values of urban structures. For many years, diaphragm walls and sheet pile walls have been widely accepted as effective deep excavation support systems for basement construction in urbanised zones. However, these are now being replaced by bored pile retaining walls as preferred earth retention systems of choice on many projects for several reasons, which may include economy, faster installation process, reduced space requirement for machinery and ancillary equipment, flexural rigidity and axial capacities.However, there are complexities associated with the use of bored pile retaining walls on urban developments. These include; limitations due to vertical and horizontal installation tolerances, which is a major issue when wall is required to provide groundwater cut-off for multi-level basements as tolerances are difficult to achieve for deep piles, uncertainty associated with the prediction of wall axial capacity as piles are rarely tested, difficulties in using temporary props as wall restraint due to restricted working spaces in urbanised zones and difficulties in adopting ground anchors as restraint due to the existence of adjacent sensitive structures in built-up areas. Such complexities have resulted in cases of failure, non-serviceability and abandonment of basement construction schemes. Therefore, overcoming the intricacies associated with the application of bored pile walls is becoming a priority to the present day basement engineer.This paper is centred on the numerical modelling, design, construction and monitoring aspects of four recent case histories of multi-level basement and marine engineering construction schemes in the United Kingdom and the Republic of Ireland, which involved the use of bored pile retaining walls. The paper highlights the various customised approaches and innovative novel solutions adopted on the sites, to mitigate risks and ultimately overcome the intricacies associated with the earth retention techniques. Simple empirical equations for developing the geometry of secant pile walls for effective groundwater cut-off are presented and validated. An alternative approach for predicting axial capacities of bored pile walls is also presented; this is shown to be considerably less conservative than a common routine design approach, while also in good agreement with observations made in a recent series of laboratory-based scale model tests."

Jan 1, 2017

By Schmitz Stefan, Stephan Jee-Sun

"Due to the reunion of Western and Eastern Germany in the late 80’s, a multitude of infrastructure projects had to be executed. A good portion of these projects required improvement of the motorway system. In the southern region of Leipzig, in the eastern part of Germany, it was required to connect two existing motorways. Parts of the new motorway pass old strip mining areas. These strip mining areas consist of up to 70m thick backfill material. Especially the upper 20m are very inhomogeneous soil material with a very low bearing capacity. In order to increase the bearing capacity, to decrease the differential settlements and to homogenize the soil parameters, soil improvement using sand-gravel columns was required. Bauer Spezialtiefbau GmbH executed the installation of approx. 711,000 linear meters of columns with a length from 5 m to 25 m. For the project, 11 rigs with frame leads up to 40m were used to install the 43,000 columns with a diameter of 0.8m in 27 weeks.1. INTRODUCTION1.1 Site LocationThe construction site is located in the south-eastern part of Germany, in the south west of the city Leipzig.The area to be treated had a size of approx. 500,000 m² to allow the construction of dam/embankments and a highway bridge.1.2 Required WorkIn addition to the general earthworks and the installation of geogrids and fibre mats, a total amount of more than 710,000 linm of Gravel-Sand Columns with different lengths due to the given soil conditions had to be installed:•nos. 4,206 Columns length 5m ? 21,030 linm•nos. 4,581 Columns length 10m ? 45,810 linm•nos. 10,820 Columns length 15m ? 162,300 linm•nos. 19,634 Columns length 20m ? 392,680 linm•nos. 3,574 Columns length 25m ? 89,350 linmFor the installation of the columns Gravel-Sand with the grain size of 0/32mm was used. The total amount of Material was 580,000mt"

Jan 1, 2015

By Brian Koch

Michels installed 242 drilled shafts to support the piers for a new basket-handle, true-arch twin bridge across the Mississippi River from Moline, IL to Bettendorf, IA. The installation of the drilled shafts was completed with the simultaneous use of two Liebherr LB36 and one IMT 300 drill rigs. Utilizing barges, 233 drilled shafts were installed in the river. Michels crews also installed 7-ft to 10-ft permanent steel casing into the bedrock, and drilled to depths of 60 feet for each shaft. Despite working in strong currents, freezing temperatures and on rocking barges, Michels crews placed the shafts within 3 inches of plan position. Since the drilled shafts are the key piece in supporting the bridge structure, Michels provided cross-hole sonic logging to verify the integrity and strength of the concrete within the shafts and to add another level of quality control for the owner/customer. Extensive planning took place each day to ensure that tugboats, the linchpin of the project, were being efficiently utilized to shift the barges and materials daily. On any given day, Michels transported five concrete trucks by barge from shore to shaft sites to pour between 40 and 240 cubic yards of concrete. The Michels environmental team was diligent with preparing, discussing and implementing a water treatment plan that was accepted by all state and federal agencies and adhered to strict environmental regulations. Grain hopper barges were rented to control and treat the water that was used in the drilling operations. Another challenge crews ran into was the discovery of caverns when drilling into some parts of the bedrock. Michels worked with the engineer to develop a plan to construct the drilled shafts that encountered the caverns.

Jan 1, 2019

By Amr Al Degwe, Walid Jaber

"INTRODUCTIONNSCC International Ltd. carried out the enabling works and constructed the foundation system for the Emirates Pearl Tower and Bab El Qasr Hotel in Abu Dhabi. Emirates Pearl Tower is a joint venture project of TDIC- Tourism Development and Investment Company and ATLAS group, a leading telecommunication company in the UAE. Bab El Qasr Hotel is a project of EMROC Emirate-Moroccan General Trading & Investment Company. The combined enabling project is executed under the combined management of JACOBS International Holdings Inc. and NASSAR Engineering Services.The project is located to the south-east of Emirates Palace and west of Etihad towers, at about 20m away from the sea shore. Since the two projects are located next to each other a combined shoring system was constructed for the entire area. This decision was based on an agreement with clients and consultants of the two projects and resulted in significant savings for both parties. The shoring system consisted mainly of diaphragm wall with ground anchors and steel struts. Cantilever secant piles were used on the eastern side of the plot, adjacent to Etihad Towers` basement.PURPOSE AND SCOPE OF WORKNSCC International Ltd. was responsible for the design, procurement and construction of strutted and anchored diaphragm walls and cantilever secant piles. The shoring layout and a summary of shoring sections are shown below."

Jan 1, 2017

By Sebastian Lobo-Guerrero

Welcome to DFI45! our first on-line annual meeting. We cannot deny the severe impacts that the COVID19 pandemic is having in our industry and our lives. We extend our support to all of our members that have been impacted in many different ways. But through the middle of this difficult and challenging times, our beloved annual conference emerges, trying to re-unite our industry and remind us why we love what we do so much. DFI45 was not originally planned to be delivered virtually, but as our world changed, we adapted. Adversity became an opportunity to re-invent our annual conference. Thanks to the vision of our Organizing Committee, we saw the amazing new possibilities and DFI45 is today a reality. Our theme for this year is People + Purpose + Passion. This theme was decided before the COVID 19 pandemic started, but today it is more relevant than ever before. We are a group of very diverse people at DFI. Our organization includes Contractors, Consultants, Suppliers, and Academics just to name a few sub-groups. But we all have a common purpose and try to find common ground. We are all extremely passionate about what we do, and this excitement is really what makes this organization what it is today. This conference celebrates this passion as you can see in our three main Keynote Sessions. On a local scale, we want to go back and remember the contribution of our industry to our beloved National Monuments in Washington D.C. On a national scale, we want to explore and recap the development of Government Guidelines and Specifications that became the world standards. And finally, we want to close the conference with a session celebrating the family legacy and share amazing stories of families with multiple generations working in our industry. Besides our Keynote Lectures, the conference is full of exciting content such as several case histories, experimental research in deep foundations, applications of new technologies, business aspects and risk management considerations for deep foundations, just to list a few. We also have our now traditional events such as the Hal Hunt Lecture, Awards Reception, DFI Educational Trust 5K Fundraiser, etc. For the first time, all this content will be delivered using different virtual formats, including on-demand presentations, plenary sessions, interactive chat rooms, etc. We are excited about these possibilities. To conclude, we need to recognize the people that against all odds made this conference a reality. First our sponsors, they adapted to the most abrupt change never thought before, and they always stayed there with us, providing unconditional support. Without them no conference is possible. Next, our Organizing Committee that re-invented the concept of an annual conference and found new and exciting ways to make this happen! Our Technical Program Committee led by our Technical Program Chairs, Jennifer Nicks and Gregg Piazza, showed us that nothing is impossible. And last, but not least, the amazing DFI staff that make dreams reality. It has been an honor to serve as the Conference Chair for DFI45. It is an experience that will stay with me for the rest of my career. Conference Chair: Sebastian Lobo Guerrero, Ph.D., P.E. American Geotechnical and Environmental Services (A.G.E.S.)

Oct 27, 2020

By Rajasekar Subbian, Jessica Oudhof

In the Netherlands pile foundation design is done using CPTs in accordance with EC7 national annexure. The capacity per tip level is calculated for every CPT followed by zonation to find the tip level per zone. The correlation factors are used to take into account the variability in ground across the zone and they depend upon the number CPTs within the zone. The CPTs and pile tip levels selection for zoning is an iterative process that can demand significant manual effort to produce an economical pile plan. This often leads to the use of conservative correlation factors in order to accelerate the design process. Thus, it has been automated in a tool with CPTs, pile location and loads, and capacities as input. The tool has also been employed in two case studies and the results are compared to the current design practise.

May 1, 2022

By Clif Kettle

The paper will detail the design and execution of passive and active settlement control measures, the means adopted to overcome the various physical and operational constraints, and to meet specified allowable settlement criteria. The paper will highlight the close integration between the tunnelling and geotechnical contractors, designer, and Client, and demonstrate how particular practical difficulties were overcome by both the design and the construction methods.

Jan 1, 2008

By N. Aarthi, G. R. Dodagoudar

The improvement of soft clay deposits using stone columns is a well-established ground improvement technique in the western world. This technique has been well documented and has proper design codes for precise execution in the field. The sand compaction pile (SCP) method is a contemporary technique to stone columns and has limited literature related to the strength characteristics of the loose to medium dense sand deposits treated with SCP. The available studies on the SCPs installed in cohesionless deposits focused on the improvement by indirectly assessing the SPT-N values pre- and post-installation of the SCPs. The widespread implementation of the SCP technique in recent years has increased the need for a more direct evaluation of the improvement. Earlier studies in this regard have revealed that the available design solutions are based on the type of installation equipment, their working efficiency, and accumulated field data. However, it is found that there are no generic design codes for the direct estimation of the ultimate bearing capacity of the SCP improved cohesionless deposits. To meet the design requirement for the SCP treated ground, a series of experimental and numerical investigations are performed in the present study to arrive at a direct framework in the form of design charts based on the pressure-settlement response of the treated ground. The developed design charts give the ultimate bearing capacity (UBC) of the treated sand deposit for the known initial relative density (RD) of the deposit, spacing and diameter of the SCPs, size of the footing, and for the specified target unit weight required for the intended application. It is concluded that the design charts will be of preliminary use to the design engineers to directly evaluate the UBC of the SCP improved loose to medium dense cohesionless deposits as part of the SCP method of ground improvement. It is expected to have more field-scale experiments and in-depth analysis before implementing these charts for actual field execution.

Nov 1, 2022

By Wanchai Teparaksa

Pile deviation generally can happen after installation of driven pile particularly in soft soil layers. In this case study, all 242 diameter 0.8 m spun piles were deviated from 20 to 820 mm. The large deviation was caused by lateral soil movement in the top very soft clay layer of thickness about 23 m. This very soft marine clay is very sensitive and anisotropic having high water contents of over 120% and low undrained shear strength of 5-10 kN/m2. The remedial works were carried out based on theory of load transfer and soil-structure interaction. All deviated piles were rectified and used as the foundation piles with strictly controlled pile load tests. The construction of a nine-storey building was successfully completed founded on the rectified piles and it has been opened for the service for over two years.

Jan 1, 2002

By Abid O. Adekunte

The design, construction and monitoring of the deep excavation support for the basement of a large-scale commercial development in Cavan, Ireland is presented. Excavation area was adjacent to existing structures and retained height H varied between 4.0m ? 11.0m. In areas where excavation depth H < 5.0m, wall was designed as cantilevered section. However in sections where 5.0m = H = 11m, additional wall supports were required for serviceability reasons. Traditionally, designers often provide additional wall support through the use of tie-back ground anchors, raking props and braces. On the current project, the main contractor was not in support of the use of temporary props so as to maximise working space, while owners of adjacent properties disapproved the use of tie-backs. The limited set-back between the wall line and site boundary also contributed to the complexity of the project. A rare alternative solution has been adopted. This novel approach involved buttressing the wall with steeply raking bored tension piles at regular intervals along the wall. Comparison of the monitored deflections in the cantilevered sections with those recorded at sections where tension piles were used shows the novel solution to be safe and quite effective. This approach is also considered to be more economical when compared with ground anchorage and propping.

Jan 1, 2008

By Gregory A. Stephan

A case history of design, prediction, instrumented static load tests on probe piles, installation monitoring, and integrity testing of production piles is presented. Based upon project-specific subsoil conditions, as obtained from several 60 to 80 ft (18.3 to 24.4 m) deep test borings, deep foundation system alternatives included driven concrete and steel pipe piles as well as augered cast-in-place (ACIP) piles. High structural loads, site-specific constraints, and the production time frame mandated by the project owner led to the selection of an ACIP pile foundation system that was designed for a pile capacity of 75 tons (667 kN) in compression and 35 tons (309 kN) in tension. Site-specific concerns were raised about the highly porous nature of fragmented and decomposed sandy limestone as well as the high grout intake during construction that could result in increased foundation cost as well as interconnecting of the piles in the rock layer. Consequentially, a multi-phase ACIP pile evaluation program consisting of instrumented compression pile load tests, in conjunction with single-hole ultrasonic pile testing, pile echo testing (sonic testing), as well as full-time production pile monitoring by an experienced geotechnician was specified. As a result of this testing and evaluation program, while grout usage was determined to be within an acceptable range, the instrumented compression load tests yielded data that allowed use of 55 ft (16.8 m) long ACIP piles in lieu of the original plans to use 70 ft (21.3 m) long precast concrete piles. This information was effectively utilized as part of the overall quality control program to install a total of 268, 14 in. (356 mm) diameter ACIP piles within the building footprint to depths of 55 ft (16.8 m) below the pile cut-off elevation as part of the foundation support system. Information recorded during installation included rate of insertion/extraction of the auger, grout pump strokes and pressure, total grout volume, and grout factors, as well as quality and strength of grout. Additionally, many pre-selected installed piles were tested for integrity with a Pile Integrity Sonic Analyzer (PISA) using both sonic and ultrasonic methods. This engineered, monitored, and tested foundation solution provided an effective and quality intensive basis for completion and approval of the foundation work for the building that resulted in cost savings over other foundation alternatives for the owner.

Jan 1, 1999

By Gary L. Seider

Chance, a Division of Hubbell Power Systems, Inc., in conjunction with Sailors Engineering, Inc. has updated its Helical Design Capacity Software. This latest version, ?HeliCAP® v2.0?, is a state-of-the-art helical anchor and pile capacity program designed to operate in the Microsoft® environment. The program calculates the tension and compression capacity along with the frictional capacity, if applicable, of CHANCE® Civil Construction helical anchors and piles using design theories and methods adopted by Chance. This paper details the current state of practice employed by the software in the design methods and installation methodologies of helical anchors and piles.

Jan 1, 2007

By Anupam Saxena

This paper presents a case history of design, prediction, probe and production pile driving monitoring, loading test, and installation of piles for a 22-story condominium tower in southwest Florida, U.S.A. ASC was commissioned to provide value engineering services in the proper selection of an economical and satisfactory foundation system. For the site-specific subsoil conditions, various types of foundations were considered and following an evaluation of high structural loads, site-specific constraints, and the production timeframe mandated by the project owner, a prestressed concrete pile-supported system was selected as an economical and effective foundation approach. The building foundations were designed for a compression capacity of 575 kN (65 tons) for the tower and 220 kN (25 tons) for the parking structure. The axial pile capacity and lengths were predicted using SPT91 software. The validation of these capacities was derived from driving 21 probe piles and performing static loading tests on selected probe piles (2 in compression and 1 in tension). The predicted pile capacities were evaluated with results from static loading tests on selected probe piles. This information was effectively utilized as part of an overall quality control program to install a total of over 920 prestressed concrete piles to lengths ranging from 11.5 to 16.5 m (37 to 54 ft) below existing ground elevation as part of the foundation support system.

Jan 1, 1996

By Suthan Pooranampillai

This paper presents a case study of the use of single axis cement deep soil mixing (CDSM) to deal with static settlement and seismic stability of the foundation soils under a reinforced soil slope (RSS) embankment up to 50 feet high. As part of the widening of Interstate 5 (I-5) to allow High Occupancy Vehicle (HOV) lanes in Tacoma, Washington, a new approach and span over the Puyallup River will be constructed. During the soils investigation and design phase of the project, low plasticity silts (ML) inter-bedded with silty sand layers and organic silt where identified as being potentially liquefiable. CDSM was selected to address the embankment foundation concerns and allow for future trenchless installation of utility lines beneath the embankment. The presence of a confined, artesian aquifer within the design depth of the CDSM led to the installation of a depressurization system to avoid an upward gradient through the wet soil-cement. In addition to addressing the design approach, the paper discusses the challenges associated with quality assurance of CDSM within the time constraints of an ongoing project. The limited recovery rate of conventional triple tube coring in the soil-cement and double tube wet sampling led to the use of sonic coring to provide a near continuous core of the soil-cement.

By Dominic Parmantier, Karen Dawson, Suthan Pooranampillai, Seungcheol Shin

"This paper presents a case study of the use of single axis cement deep soil mixing (CDSM) to deal with static settlement and seismic stability of the foundation soils under a reinforced soil slope (RSS) embankment up to 50 feet high. As part of the widening of Interstate 5 (I-5) to allow High Occupancy Vehicle (HOV) lanes in Tacoma, Washington, a new approach and span over the Puyallup River will be constructed. During the soils investigation and design phase of the project, low plasticity silts (ML) inter-bedded with silty sand layers and organic silt where identified as being potentially liquefiable. CDSM was selected to address the embankment foundation concerns and allow for future trenchless installation of utility lines beneath the embankment. The presence of a confined, artesian aquifer within the design depth of the CDSM led to the installation of a depressurization system to avoid an upward gradient through the wet soil-cement. In addition to addressing the design approach, the paper discusses the challenges associated with quality assurance of CDSM within the time constraints of an ongoing project. The limited recovery rate of conventional triple tube coring in the soil-cement and double tube wet sampling led to the use of sonic coring to provide a near continuous core of the soil-cement.IntroductionCement deep soil mixing (CDSM) was used as a replacement for stone column ground improvement in a corridor which the owner, the Washington State Department of Transportation (WSDOT) wanted to reserve for future trenchless crossings beneath reinforced soil embankments within a freeway interchange. The work was part of HOV improvements to I-5 in Tacoma, Washington. The CDSM construction occurred in late 2010 and early 2011.Approximately 14,500 cubic yards of soil cement columns were placed by CDSM. The soil cement improved ground supports permanent geosynthetic reinforced slopes up to 50 feet high. The ground improvement was designed primarily to provide global stability of the reinforced slopes during seismic loading, but it was also utilized to reduce the time and total amount of settlement following construction of the embankments.This paper presents a discussion of the design approach and challenges associated with quality assurance of a relatively small volume of CDSM within the time constraints of an ongoing project. The challenges associated with attempts at collecting cores of the cured soil-cement mix cured by triple tube coring and pushing a double tube into the wet mix and allowing it to cure insitu are discussed, along with the eventual adoption of sonic coring combined with reliance on laboratory testing of wet mix samples collected daily."

Jan 1, 2017

The pile inspector is a critical element in the quality control process necessary for a successful pile installation project. This guide is intended to provide the inspector with a basic understanding of only one of the many components of this process - the pile driving hammer. Pile driving hammers are used to install both bearing piles for structure foundations and sheet piles (and soldier piles) as used in retaining structures. In a single document, this guide offers a general presentation of the operation of the more common types of hammers the inspector is likely to encounter. It should make the information in the contractor&apos;s hammer submittal for the project more understandable. It should also provide an appreciation for the importance of a properly operating pile hammer. Prior to the start of most pile driving operations, the contractor will normally furnish a submittal to the engineer giving the specific pile driving equipment that he intends to use on the job. This submittal should include the make, model, and type of the intended pile driving hammer or hammers and their operating characteristics such as ram weight, rated energy, operating speed, external power requirements and, other pertinent information. Frequently, the operating characteristics are provided in the form of the manufacturer&apos;s specification sheet. The engineer will review this information and when he is satisfied, approve it and pass it on to the inspector. The driving criteria will have been determined by the engineer or others (the geotechnical engineer, consulting engineer, contractor, etc.) from the results of static analysis (for minimum penetration), driving during a test pile installation, Wave Equation analysis, dynamic formula, pile instrumentation during driving, static load test, or a combination of these or other appropriate analyses. The driving criteria can be a minimum penetration of driven pile length (embedded length), or a minimum (or maximum) blow count per unit of penetration. The pile inspector should become familiar with this information prior to the start of the job and should understand or seek help to comprehend the terminology and intent of each specification.

Jan 1, 1995