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By Michael Gebman, Jack Gerwick

"With the opening of the new San Francisco-Oakland Bay Bridge East Span, the former bridge and its caisson foundations are being demolished. Caisson foundations are in the path of a future shipping channel and therefore need removal down to the mudline 50 ft below water (MLLW). For the first caisson to be removed (E3) a mechanical demolition was performed above the waterline and an implosion was done for the remaining caisson down to mudline. Mechanical demolition consisted of excavators operating from either on top of the caisson, from work platforms or from barges. The demolition was implemented on a trial basis with a successful implosion on November 14, 2015. The work was conducted in an environmentally sensitive area, with measures taken to protect fish, marine mammals and birds. This demolition technique was cost effective, faster to execute, and had a better environmental impact then an alternative option. The demolition, measures implemented to protect the environment, outcome, and lessons learned are presented.INTRODUCTIONThe California Department of Transportation needed a cost effective and environmentally friendly solution for removal of the remaining San Francisco-Oakland Bay Bridge (former East Span) caisson foundations, starting with caisson E3. This was necessary to clear a future shipping channel. One option was to construct a steel cofferdam around the caisson to allow demolition in the dry down to the mudline. This option would take years to complete, be cost prohibitive, and its noise would disrupt aquatic life and birds throughout the cofferdam construction and demolition. An alternative option was implemented on a trial basis to conduct a mechanical demolition of the caisson above waterline along with an implosion of the remaining caisson down to mudline. This had the clear advantage as a cofferdam was not needed, and the demolition project duration would be approximately 6 months, instead of several years for the cofferdam option. The potential impact on aquatic life and birds from the implosion was a concern, as the location is environmentally sensitive; however, measures were implemented to minimize these impacts. As presented in this paper, this demolition option was implemented on a trial basis for Caisson E3. The technique succeeded and will now be used on the remaining caissons.BACKGROUND INFO ON CAISSON E3The reinforced concrete Caisson E3 is the largest caisson which supported the former East Span of the Bay Bridge. It was constructed in 1934, with the Bay Bridge opening in 1936. Figure 1 shows the project location. The caisson had a cell arrangement of 7 x 2 above the mudline. Below mudline, the caisson had a cell arrangement of 9 x 4. A structural transition was made between the 7 x 2 and 9 x 4 cell arrangements with buttress walls. All cells were flooded, as underwater openings were included in the original caisson walls to equalize the hydrostatic pressure. Figure 2 shows the caisson layout with limits for mechanical demolition and for the implosion."

Jan 1, 2016

By Seth Robertson, Daniel Belardo, Travis Coleman

Thermal Integrity Profiling (TIP) is a non-destructive method used to evaluate drilled deep foundation integrity. This integrity testing method is specified more frequently, and is becoming an industry standard in the transportation and private construction sectors. This testing method utilizes heat generated during the concrete/grout curing process to assess deep foundation integrity over the evaluated length. With compilation of the measured temperature versus time and installation records, a model of the Effective Average Radius versus measurement depth is generated. The generated effective shaft model is highly dependent on specific construction details, subjective modeling parameters, and proper interpretation of concrete/soil heat dissipation characteristics. Key components of the TIP analysis include both qualitative and quantitative assessments. Qualitatively, variations or sharp reductions in temperature profiles may indicate potential anomalous regions. Quantitatively, a correlation is established between measured temperatures and estimated Effective Radii for subsequent integrity evaluation. Best practices in processing the TIP measurements are presented, including selecting the optimal time for analysis, normalizing the thermal profile, and proper interpretation of potential anomalous regions. Recommendations for implementing mitigation efforts and interpretation of the TIP results are presented.

Sep 8, 2021

By John Kvinsland

"The Block 43 Project is the future home of the Paul Allen Institute for Brain Science located just off the southern shore of Lake Union in Seattle, Wash. The South Lake Union (SLU) district experienced considerable development over the last 10 years and Vulcan, Inc., which is headquartered in Seattle, is at the forefront of this transition. Once a light industrial/residential location, SLU has transformed into a hub of medical technology comprising new residential units and mixed-use buildings. Malcolm Drilling Company, Inc. constructed four shoring projects for Vulcan in this vicinity over the last year, beginning with Vulcan Block 44, which consisted of 42,000 sq ft (3,902 sq m) of soldier pile and tieback wall to support a below-grade parking facility. Block 44 construction began in February 2013 and ended in mid-April. The feature project, Vulcan Block 43, was in planning stages at the time and began construction in late fall 2013.Awarded by GLY Construction of Bellevue, Wash., in September 2013, Block 43 was the most complex of the block projects performed by Malcolm. Block 43 featured dewatering and ground improvement components along with a water-tight secant pile wall. Following the commencement of Block 43, Malcolm also began work on Vulcan Block 52 in December 2013. Block 52 consisted of 43,000 sq ft (3,995 sq m) of conventional shoring in conjunction with dewatering of 8 ft (2.4 m) of excavation located below the water table. The final Vulcan project was Block 45, which started in January 2014 for Turner Construction of Seattle and consisted of 41,000 sq ft (3,809 sq m) of conventional shoring and required dewatering to complete the final 15 ft (4.6 m) of excavation.Scope and Subsurface ConditionsBlock 43 involved a wide variety of drilling applications for the building to be constructed and properly founded. The primary scope of work involved shoring support for an underground parking structure requiring excavation of approximately 82,000 cu 3 yds (62,694 m ) of soil. The cuts for the excavation were up to 43 ft (13.1 m) in depth, and the excavation was bounded by city streets as well as the South Lake Union Light Rail on its perimeter. In order to excavate beneath the water table, an extensive, deep dewatering system was required to drain the upper fill and reduce the impact of the pressurized aquifer located beneath the excavation. In addition, drilled rigid inclusions, along with compaction grouting, were required for foundation support of the future structure."

Jan 1, 2014

By Steffen Schweizer, Tadeusz Brzozowski, Alfred Koller, Michał Topolnicki, Jürgen Wäger, Grzegorz Sołtys

A full scale test has been conducted to determine ground bearing pressure under rig tracks. The track loads were recorded in real time using Liebherr's Ground Pressure Visualisation system, and the vertical stress induced in the ground was measured with pressure cells embedded in the ground. It has been found that the recommendation of EN 16228 regarding determination of the track length is oversimplified. The contact length should dependent on the susceptibility of the working platform. It has been also demonstrated that the corrected pressure distributions under the tracks influence the dimensioning of the working platforms. As a result, the designed working platform may actually be less secure than is shown by conventional calculations.

May 1, 2022

By Howard A. Perko, Margaret Dring, Gerald Verbeek, Scott Slaughter

Helical piles have become a widely used deep foundation system in recent years due to their many inherent advantages. The cone penetration test (CPT) is commonly used in geotechnical practice to evaluate subsurface conditions for deep foundation design as the method provides a continuous soil profile in a short amount of time, measures in-situ soil strength, and in many ways behaves similar to a “mini pile” during penetration. In the CPT test, an instrumented cone is hydraulically advanced into the soil at a constant rate. As the cone is advanced, strain gauges embedded in the cone body continuously measure the tip resistance and side friction. In addition, a piezometer element is commonly used to measure the (dynamic) pore water pressure in the soil as the cone is advanced. A study was conducted comparing the CPT tip resistance to helical pile installation torque and capacity. In this paper, the outcome of this study was compared with historical data of helical pile installation torque records, static analysis predictions using commonly used techniques, and pile load test results over a wide range of soil conditions. A literature review was also conducted where a comparison was made for CPT tip resistance and helical pile installation torque data with previously published correlations.

Sep 8, 2021

By Robert Bachus, Jamey Rosen, Fabio Santillan, Georgette Hlepas

"A seepage barrier of length 4,800 feet and maximum depth 144 feet is being installed at Bolivar Dam in Ohio. This project is owned by the United States Army Corps of Engineers and contracted to Treviicos South. Many data types are being collected, synthesized and analyzed on a nearly real-time basis to monitor and track dam construction using several technologies including an enterprise relational database and web-based Geographical Information Systems. These data are being collected by both the owner and contractor and managed by the data subcontractor, Geosyntec Consultants. Each of the owner and contractor brings their own list of goals and desires to the data management program, and the subcontractor’s duty is to address these goals with minimal compromise by either party. The owner requires comprehensive, transparent and timely access to data in both “executive summary” and detailed formats. The contractor requires immediate analysis of disparate data to determine (for example) if a given excavation meets the specified tolerance and continuity requirements. This paper will describe the tools and methods used to store, analyze and visualize these data and discuss how each party’s needs were met in a collaborative system.INTRODUCTIONThe 4,800 foot long seepage barrier under construction at Bolivar Dam requires the collection, organization, and sharing of several types of data. These data include drawings and borehole logs that existed prior to construction; data collected during construction (seepage barrier panel composition and verticality data, slurry quality control and quality assurance data, grouting records, etc.); and instrumentation data collected and reviewed throughout and beyond construction. Each of these data streams require input and review from the Owner (United States Army Corps of Engineers (USACE), responsible for quality assurance and the ultimate consumer of the data), the Contractor (Treviicos South, responsible for the construction of the seepage barrier, its quality control and analysis of the data per the Contract Specifications), and the Data Management Subcontractor (Geosyntec Consultants, responsible for organizing and presenting the data to meet the needs of the Owner and Contractor). While all parties work with the same common goal, i.e.: producing a high quality product in an efficient manner making dam safety paramount during construction, and require immediate and comprehensive access to these data, the needs and desires of the parties differ. The challenge presented to the Data Management Subcontractor is to synthesize these data into a series of tools and reports that meet each of these needs."

Jan 1, 2017

By Zaw Zaw Aye, Sereyroath Chea, Nutthapon Thasnanipan, Thayanan Boonyarak

"As there are only limited numbers of bored pile constructed in sandstone and siltstone in Thailand, load transfer and settlement behavior of a pile in these rocks are still not fully understood. Major factors which influence the performance of the pile in the sedimentary rock should be systematically investigated. The objective of this paper is to analyze load distribution and load-settlement behavior of bored pile in sedimentary rock. Interpreted data was obtained from instrumented load testing results of large-diameter bored piles. These piles were drilled in aeolian soil and socketed in sandstone or siltstone, having socketed length varying from 1 to 3 times the pile diameter. Factors that influenced pile settlement behavior, consisting of rock type at the pile base, socket length, at-rest earth pressure and rock conditions, were analyzed. For interpretation of results, analytical solutions were used to estimate load bearing capacity and calculate settlement of each pile. According to test results of mobilized unit skin friction in siltstone, relationship of 0.1 – 0.3 square root of the unconfined compressive strength of rock appears to reasonably capture the measured shaft friction. Note that shaft movement in siltstone layer was not fully mobilized as maximum pile head settlement was still less that 1% of the pile diameter.INTRODUCTIONExtensive research of bored pile construction in soft soil in Thailand and Myanmar (Boonyarak et al., 2016; Aye et al., 2015) has been carried out. However, behavior of bored pile in weak rocks such as sandstone and siltstone is still not fully understood. Unit skin friction and unit end bearing of piles in these weak rock were reported by Horvath et al. (1983) and Pells and Turner (1980), respectively. Further research is still required to minimize variation in data presented in their study.This paper presents interpretation of load testing results of instrumented piles. These piles were excavated in aeolian deposit in the Northeast Thailand. Some piles were socketed in sandstone or siltstone. Analysis results of load-settlement, shaft shortening, pile settlement estimation, factor for calculating shaft friction and end bearing are reported. Discussion and explanation of pile behavior in sandstone and siltstone is provided.BRIEF INFORMATION OF THE PROJECTProject locationsThe construction sites are located in Khon Kaen and Nakhorn Ratchasima Provinces in the Northeast Thailand. Bored piles in this project were designed for supporting elevated structures for railways, overpasses and U-turn bridges for vehicles. These overpasses and U-turn bridges are distributed along the existing railways with the distance of about 180 km."

Jan 1, 1900

By Armin W. Stuedlein, Steven R. Saye

The differences between calculated axial pile capacity and the capacity realized during and following installation has long presented a significant concern for foundation engineers and contractors. Such differences have increased in prevalence with the increased use of larger diameter steel pipe piles and the significant increase in design-build contracting. The writers present concepts to close the gap between calculated axial pile capacity and the capacity realized during and following installation of driven pile foundations, including: (1) pile set-up in plastic soils, (2) limitation of re-driving of piles after setup which serves to reduce pile capacity, (3) the use of a vibratory hammer to install piles in cohesive soils disturbs the supporting soils and reduces the pile side resistance capacity significantly, and (4) long pile installation times for open-ended piles can damage the pile side resistance. Examples are presented from practice to illustrate these concepts and to guide pile installation planning to recognize the installation impacts and either consider alternate installation approaches or to properly consider the installation impacts during design.

By Edward C. Clukey

A deep mixing method (DMM) foundation was selected by the Project Team for a very largeLNG facility in West Africa. As described in a companion paper, this foundation consists of alarge number of columns installed by mixing cement with in-situ soils. The foundations arearrayed as a variety of honeycombed type configurations which, if installed to desiredspecifications, can provide a robust foundation alternative. The foundation is capable ofdistributing loads and limiting settlements even if some of the soil in the columns is not fullymixed during installation. An important part of the overall quality assessment program,therefore, involved developing a testing program to verify the methodology. In addition theimpact of potential defects in columns on the overall foundation integrity had to be assessed.This paper describes some of the preliminary work done to establish the requirements for thequality assurance program. A key component of this program involved the samplingfrequency used to assess potential defects in the columns. To verify the column integrity 104-mm samples were taken continuously at a selected frequency through the 23 m longcolumns. The preliminary work described in this paper demonstrated that the appropriatesampling frequency depends on both the desired reliability level as well as the number ofdefective columns encountered during testing. Initial finite element analyses were performed to assess the extent that defects could occur incolumns within the honeycombed structure without adversely affecting the overall foundationintegrity. The results from this work demonstrated that the spatial location of the defects wascritical to properly assessing the foundation integrity. In addition to column sampling a load test was performed as part of the foundationverification process. The methods used to apply appropriate loads so that loads at thebottom of the columns approached design values are discussed in the paper. The results obtained from this preliminary study were then used to help develop a morecomprehensive assessment program, described in a companion paper, to determine therobustness of the DMM foundations for both the LNG processing facilities and a condensatetank.

By Ramanathan C, Prasad P. V. S. R

The most critical challenge for any large size storage structures to be constructed on soft compressible soils is bearing capacity and consolidation settlements. Consolidation is the time dependent phenomena, as expulsion of water from soil voids on application of external load will take longer period. It is mainly influenced by soil consistency, permeability, thickness of compressible stratum and presence of free draining layers. This study deals with the foundation solution of a large size Mounded Storage Vessel (MSV) to be constructed on thick compressible stratum whose loading intensity is around 155 kPa and the estimated settlements are greater than 400 mm. Hence, the foundation solution using vibro stone columns is adopted as an effective technique to address the challenges of excess settlements and inadequate bearing capacity. Further to keep settlements within the permissible limit of 50 mm, preloading technique with 60% of actual loading intensity will be utilized. The consolidation analysis of stone column reinforced foundations is carried based on the method given by Han and Ye (2001). The quality of the stone columns is ensured by real time quality control measures and the performance of the stone columns shall be ensured by vertical load tests. Ground settlements was closely monitored with proper instrumentations and the actual degree of consolidation has been verified by Asaoka’s (1978) method.

Sep 1, 2022

By Paul Summers, Kevin Richardson, Willem (Billy) Villet, Paul J. Sabatini, Attasit Korchaiyapruk, Edward C. Clukey

"A deep mixing method (DMM) foundation was selected by the Project Team for a very large LNG facility in West Africa. As described in a companion paper, this foundation consists of a large number of columns installed by mixing cement with in-situ soils. The foundations are arrayed as a variety of honeycombed type configurations which, if installed to desired specifications, can provide a robust foundation alternative. The foundation is capable of distributing loads and limiting settlements even if some of the soil in the columns is not fully mixed during installation. An important part of the overall quality assessment program, therefore, involved developing a testing program to verify the methodology. In addition the impact of potential defects in columns on the overall foundation integrity had to be assessed. This paper describes some of the preliminary work done to establish the requirements for the quality assurance program. A key component of this program involved the sampling frequency used to assess potential defects in the columns. To verify the column integrity 104- mm samples were taken continuously at a selected frequency through the 23 m long columns. The preliminary work described in this paper demonstrated that the appropriate sampling frequency depends on both the desired reliability level as well as the number of defective columns encountered during testing.Initial finite element analyses were performed to assess the extent that defects could occur in columns within the honeycombed structure without adversely affecting the overall foundation integrity. The results from this work demonstrated that the spatial location of the defects was critical to properly assessing the foundation integrity.In addition to column sampling a load test was performed as part of the foundation verification process. The methods used to apply appropriate loads so that loads at the bottom of the columns approached design values are discussed in the paper.The results obtained from this preliminary study were then used to help develop a more comprehensive assessment program, described in a companion paper, to determine the robustness of the DMM foundations for both the LNG processing facilities and a condensate tank.IntroductionFoundations constructed with the Deep Mixing Method (DMM) can be an attractive and cost efficient alternate to other deep foundation options. This foundation is constructed by mixing soil and cement with an auger type drill. The foundation is usually constructed with a dual auger system that simultaneously creates two contiguous columns called foundation elements. Many elements are then arranged in a honeycombed configuration to create the overall foundation (Figure 1). A desired column strength can be obtained by varying the volume of cement added to the columns, the mixing rate of the soil and stroking sequence."

Jan 1, 2017

By Phillip E. Glogowski, N. Catherine Bazan-Arias

Steel foundations can be designed to cross-sectional configurations ranging from triangular and square to other multi-side shapes. Adding lateral extensions (hereby called wings) along the length of the steel stem can increase the foundation’s uplift, torsional and lateral load capacities. DiGioia Gray staff developed a methodology for the optimal design for multi-facetted, winged deep steel foundations. A finite element (FE) model is used to represent the steel components and the nonlinear subsurface behavior. The geometry of the foundation can be complex; thus, an optimal design needs to be fine-tuned to the specific site conditions. We created a pre-processor tool to generate the FE model including varying values for the number and size of wings, depths of embedment, reveal/stickup heights, top plate geometries, and subsurface profiles. The analytical model has been partially validated through full-scale testing and the methodology has been applied to two installed projects to date.

Sep 8, 2021

By Brandon Smith, William Bohlen

Riverbank erosion along the Brazos River has modified the structural support conditions for an existing bridge structure in Southeast Texas. The 8-span, 1,200-foot long bridge was completed in 1992 along Highway 99, a key corridor for the Houston area. Foundation support conditions have been altered due to natural, ongoing river morphology for three bents on the affected riverbank. Recent events include three storms within a three-year period that each exceeded the 500-year return probability. This resulted in accelerated erosion along the northern riverbank. Over forty vertical feet of soil has been removed in some locations. Drilled shaft foundations are now functioning as columns. This review considers the behavior of columns and deep foundation elements due to the modified support conditions. The review ultimately presents a rational methodology for the review of the present and anticipated future bridge configuration with respect to current strength, service, and extreme event limits, with corresponding safety factors for the design. Introduction and Background The Fort Bend Grand Parkway Toll Road Authority (Owner) oversees the State Highway 99 Judge Jodie Stavinoha Bridge over the Brazos River. The 8-span, 1,200-foot long bridge was originally designed with four southern approach spans of 115 feet; a three-span continuous river crossing with span lengths of 195 feet-235 feet-195 feet; and a single northern approach span of 115 feet. Figure 1 provides an overview of the northern portion of the bridge. Table 1 provides a summary of the original bridge substructure configuration. When the bridge was completed, the centerline of the Brazos River was located at midpsan of the main span and the northern high bank was originally located at Bent 7. Erosion process has forced the northern high bank to Abutment 9 (also called Bent 9), and the river centerline during normal flow conditions is located south of Bent 8. The overall estimated river excursion at present day is approximately 270 feet to the north from its original location. An erosion wall that was installed in 2017 limits further erosion of the north river bank within the 300-foot width of the roadway corridor right-of-way. This study was developed to better understand the existing conditions, and to forecast the need, nature, and criteria for potential future improvements.

Jan 1, 2019

By Paul M. Schuman, Alessandro Bertero, Giuliana A. Zelada, Sharon G. Cranston

Many jet grouted columns were recently installed to create a jet grout-treated soil foundation for an earthen embankment used in a large shoreline stabilization project in the Mystic River in Charlestown, MA. A physical test program was used to determine whether the jet grouting parameters the Contractor selected would meet the design requirements given the local soil variability, including soft river sediments and organic soils. The presence of hydrocarbons encountered in the marine sediments during the test program caused concern that the design strength could not be achieved. The published literature discusses the environmental aspects of jet grouting with hydrocarbons. The literature did not include many studies of the effect on jet grout-treated soil strength for the types and concentration of hydrocarbons encountered on this project. The grout mix, air pressure, and number of passes of jet grouting were varied in a second field test program to determine jet grouting parameters needed to achieve the design strength of columns with hydrocarbons. A geo-probe study was performed to identify the type and concentration of hydrocarbons on the site. With few exceptions, the quality control core samples from the production columns met the design requirements with many strength values far exceeding the design strength. This paper presents the data, and reviews the lessons learned. PROJECT BACKGROUND The Charlestown Bus Garage, located in Cambridge, Massachusetts, is a Massachusetts Bay Transportation Authority (MBTA) bus maintenance facility located on the Mystic River. The site was home to a coal gasification facility before it was developed by the MBTA as a bus garage in 1978. A deadman-anchored steel sheet pile bulkhead wall installed along the Mystic river on the east side of the site supports the site grade at about El. 11 ft (NAVD 1988) (Figure 1).

Jan 1, 2019

By Clarissa Aguiar, Seok hyeon Chai, Thamer Yacoub, Sina Javankhoshdel

Sheet piles are used as an excavation support for soil retention. They are interlocked systems to form a wall for earth support along with anchors to provide an extra lateral support in excavations. The earth pressure against a sheet pile structure is not unique for each soil, but rather a function of soil-structure system. Movements of the structure with respect to the soil are primary factor in developing the pressure and thus the problem becomes indeterminate. In order to model a sheet pile wall for the analysis, structural element/interface can be used for the sheet pile. However, the use of the structural element with soil model alone is insufficient to simulate this soil-structure system as it fails to capture the slip condition between the sheet pile and the retained soil. In order to capture this slip condition, an interactive element can be used between sheet pile and soil to allow slip to occur. There have been many case studies where this method was used to analyze the response of the retained soil. Numerical studies have shown a good agreement with experimental results, but this stiffness is often not a well-known parameter, due to its complexity in nature of interactive behavior between soil and sheet pile walls. Also, many case studies are carried out with twodimensional analysis of the foundation, where three-dimensional analysis may be more suitable in some practical applications. In this paper, the interactive behavior of the element between sheet pile and soil is investigated with case studies for staged excavation using sheet piles and anchors. Then, investigation of a three-dimensional model is carried out by comparing with two-dimensional analysis.

By Yan Lap J. Kan

"A waterfront stabilization system consisting of Deep Soil Mixing (DSM) columns, vinyl sheet pile fascia, and concrete flood walls supported on shallow footings was designed and constructed for a high-density waterfront development in Northern California. The project site is underlain by soft, compressible organic soil locally known as Bay Mud that has been capped with loose sand and imported fill. The waterfront stabilization system constructed at the site mitigates liquefaction, consolidation settlement and seismic potential slope deformation along the waterfront; the system was designed to reduce lateral displacements to tolerable amounts for the proposed structures. This paper presents the general design methodologies, construction challenges and quality control of this waterfront stabilization system.INTRODUCTIONUrban development in Northern California is fueling innovations in geotechnical engineering as more complex sites are developed. ENGEO Incorporated introduced a deep soil mixing technology from Japan to the US and designed a waterfront stabilization system for a high density waterfront development project in Redwood City, California. The approximately 12½-acre project site, as shown on Fig. 1, is surrounded by water on three sides, with an inner marina at the center of the site.The project site is located in the seismically active San Francisco Bay Area in California. The San Andreas Fault, the Monte Vista-Shannon Fault, the Hayward Fault and the San Gregorio Fault are major active faults located within 25 miles of the site. Once a former marshland with a major slough until the late 1950s, the site was reclaimed by placing imported fill over the native compressible clay deposits, locally known as Bay Mud."

Jan 1, 2016

By Hayel M. El-Naggar, Mohamed Sobhi, Mamdouh M. Hamza, Marawan M. Shahien

"This paper presents the results of two lateral load tests on large bored piles in soft clay deposit for a major site in northern Egypt. The tests are carried out on 0.8 m diameter piles. One of the tests is carried out on the pile where the clay starts from the ground surface. The other test is carried out on a pile after surface improvement by replacing the top 1.50 m of the clay deposit by compacted granular soil. The results of the tests show the influence of the surface replacement layer on the lateral load versus lateral displacement relationships of the loaded pile. The results of the two tests are used to calibrate a 3D Finite Element Analysis model for the pile. The model is used to investigate the influence of the thickness and lateral extent of the surface replacement layer on the behavior of laterally loaded large bored piles.INTRODUCTIONLateral loads for piles are produced by seismic events, wind, wave action, ship impact, traffic, and land slide forces. The lateral resistance of a pile is controlled by the stiffness and the strength of the material of the pile and the soil surrounding the upper portion of the pile. In most situations, the soil surrounding the upper portion of the pile is too weak to sustain the design lateral loads. Thus there is a need to increase the lateral resistance of the pile or groups of piles. Such an increase may be achieved by either increase number of piles or increase pile diameter. Alternatively, an economic way to increase the lateral resistance is to improve the soil surrounding the upper portion of the pile (Rollins and Brown, 2011; Faro et al., 2015).Ground improvement has the ability to increase the lateral resistance of the pile by increasing the passive resistance of the soil surrounding the upper portion of the pile. The ground improvement techniques have the potential for being more cost-effective and reducing construction time. In spite of this fact, such techniques are rarely implemented in practice. Further, there are relatively few tests or records available in the literature to guide engineers in evaluating the actual effectiveness of this approach. In addition, there is no standard or methodology to aid engineers in designing increase of lateral resistance with surface ground improvement. There are specific improvement methods for each soil type, whether it is loose cohesionless soil or soft cohesive soil and these methods are provided by Michell (1981), Tershai and Juran (2000), ASCE (1997), and Rollins and Brown (2011). Furthermore, there are number of case histories that add a new hole in the sight, such as the cases provided by Brown et al. (1987, 1988), Mokwa and Duncan (2001), Rollins et al. (2005), Rollins and Cole (2006), Cole and Rollins (2006), Rollins, Snyder et al. (2010) , Rollins, Gerber, and Kwon (2010), Rollins and Nasr (2010), and Gerber et al. (2010)."

Jan 1, 2016

By Francisco A. Flores, Rigoberto Torres

The Complementary Technical Standards of Mexico’s City Building Code do not mention the criteria to compute the bearing capacity of Steel H-piles. It is necessary to increase knowledge in using steel H-piles as foundation elements in very soft soils of Mexico City. Considering their applicability to reinforce structures as well as new foundations in confined spaces, this research is proposed to obtain the axial load capacity of piles at scale in laboratory. This paper describes the construction and testing of scale models in laboratory of steel H-piles to measure their axial compression and tension load capacity in the soft soils of Mexico City. Three types of piles were fabricated at scale. Tests were performed on individual piles and pile groups. Based on the axial load tests, the load-displacement curves are presented both in compression and tension. The analysis of the results is shown, and comments are given regarding the ultimate bearing capacity of piles. Recommendations are presented regarding the determination of the bearing capacity of these piles in the very soft soils of Mexico City.

Sep 8, 2021

By Shawna Munn, Nadir Ansari, Toben Jerry

With ever increasing demands on space in urban environments and smaller available footprints, buildings are being designed to increasing heights to meet the need. This case study discusses the increasing challenges in developing projects within urban environments with smaller available footprints and increasing building heights. The One, Canada’s tallest residential building under construction will stand at 85 storeys and is located at one of the most prominent and built up intersections in Toronto, Yonge Street and Bloor Street. This led to many challenges in design and construction of the shoring and foundation work, including the required design capacity of the foundations for the supertall building and proximity of the large diameter drilled shafts to the excavation shoring wall. This case history describes the shoring design option evaluation, performance, and lessons learned to date throughout construction of the building foundations within a small congested site. PROJECT OVERVIEW The One, Canada’s tallest residential building under construction by Mizrahi Developments, is a supertall building that will stand at 85 storeys and 306 m (1005 ft). The first 18 floors will be comprised of retail, restaurants, and hotel with luxury residential condominium units in the tower above. The project is located on the Southwest corner of Yonge Street and Bloor Street, one of the most prominent and built up intersections in Toronto. The L-shaped excavation measures 58 m by 47 m (190 ft to 154 ft) and ranges from 22 m to 28 m (72 ft to 92 ft) in depth with one internal corner projecting 11 m (36 ft) into the site.

Jan 1, 2019

By Mark Zablocki, Dakarai McCoy

Ground vibrations are an unavoidable effect of driving piles and may pose a risk to nearby infrastructure and the comfort of adjacent occupants. Driven-pile-induced ground vibrations are known to vary widely based on ground conditions, pile material, and installation means and methods. A monitoring sensor to record ground vibrations during pile driving is necessary for understanding potential impacts to sensitive infrastructure and should be considered when implementing a monitoring program anticipating ground vibrations. The implementation of a vibration monitoring program historically relies on experiential-based decision-making, which may result in the costly vibration monitoring of low-risk infrastructure. Prior understanding of anticipated ground vibrations is necessary to create an appropriate monitoring program. A framework is proposed for organizing data from past monitoring programs and quantifying the anticipated risk of driven-pile-induced vibrations. An example of risk quantification from data imported to ]a cloud database is presented by comparing driven steel H-pile and prestressed precast concrete vibration monitoring measured and collected by Haley & Aldrich between 2010 and 2020. The methods presented within the example can be applied to quantify a first order approximation of risk for ground vibrations at proposed driven pile sites based on the measured performance of previous sites with similar ground characteristics and pile installation methods. The presented novel data managements tools allow for a quick aggregation of vibration data with similar site conditions.

Sep 8, 2021