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By Noreen Tarac, Pablo Forgoso, Philipp Schober

A multiple use storage facility building is being developed in the Philippines on a peninsula that was reclaimed in the 1990s without any soil treatment. The subsoil now consists of loose to medium dense silty sand underlain by a soft to medium stiff clay. A liquefaction assessment by analytical methods have shown that the loose to medium dense silty sand yields a high potential for liquefaction and lateral spreading during pthe design level seismic event. To mitigate the risk of liquefaction and lateral spreading, as well as assure the slope stability of the shoreline, a solution utilizing a combination of ground improvement techniques by means of a Mixed-In-Place (MIPTM) Lattice Grid Wall and Stone Columns was developed and successfully executed. For the detailed seismic design, a Finite Element 3D analysis was undertaken to simulate static and dynamic actions on the buttress wall. The liquefaction assessment and settlement calculation were carried out based on analytical design approaches. For the execution of the Lattice Grid Wall, the Mixed-In-Place (MIPTM) method developed by BAUER Spezialtiefbau GmbH was applied. The stone columns were installed using the Wet Top Feed method.

Sep 8, 2021

By Vijaya Bhushan Rao, Jason Redgers

A mixed-use development comprising of multistoried residential towers, retail and associated infrastructure covering an area of 500,000 m2 is under construction in Dubai. The subsoil conditions consist of calcareous sands with high carbonate and shell content with hard and competent strata encountered at varying depths. To achieve the design requirements of soil stiffness, friction angle, limit differential and total settlements and mitigate the liquefaction due to a seismic event then ground improvement were deemed necessary. In order to provide the most time and cost efficient solution numerous techniques were applied to meet the requirements for all depths such as Vibrocompaction, VC (depth >8m), Dynamic Compaction, DC (depth < 8m)] and Rapid Impact Compaction, RIC (depth <4m). The specified ground improvement requirements were translated into a target Cone Penetration Test, CPT line that served as the defacto performance requirements for the project. Suitable correction factors were applied to the CPT results to account for the high carbonate content following the works of Al-Homoud and Wehr 2006, Belotti and Jamiolkowski , 1991 and Vesic, 1965. Furthermore, the alpha factor, α, used to obtain stiffness from CPT results was applied following A.C. Meigh 1987 and Massarsch & Fellenius, 2005 where high over consolidation ratios (OCR) could be demonstrated.

Sep 8, 2021

By Kevin Baumgartner, Steven Babcock

A landfill in Phoenix, AZ reached capacity and was graded over in the 1970s. The property was subdivided into lots in 2007 to create a business park. However, the challenging site conditions caused by the underlaying landfill put into question the feasibility of typical deep foundation systems. Several different foundation systems were evaluated to support the proposed development. The considered systems were: drilled concrete shaft, driven piles, drilled micropiles and helical piles. Soil stability, landfill decomposition, method of installation, flexibility of design, anticipated material, and equipment costs were considered. A system of helical piles with concrete pile caps and grade beams was selected. To mitigate unknown obstructions, holes were drilled through the landfill debris at pile locations and then backfilled with screened granular material. The helical piles were installed through these backfilled holes and advanced to bear in competent native material below the landfill. This method allowed for minimal disturbance of the landfill materials and provided a strong and adaptable foundation. Additional advantages of helical piles on this site include minimal installation vibration, no grout or concrete in the deep foundation, and capacity verification for each pile via torque correlation. Two load tests were performed to verify the design.

Sep 8, 2021

By Ramin Motamed, Fahim M. Bhuiyan, Raj V. Siddharthan, Joseph Toth

The difficulty in material characterization and the erratic response of cemented soil layers, such as caliche in the Las Vegas valley, creates challenges for practicing engineers to reliably predict the response of deep foundations. The focus of this paper is the numerical prediction of axial response in drilled shaft foundations, which are commonly used in infrastructure projects (i.e., bridges and tall buildings) in Las Vegas, NV. The prevalence of hard caliche layers with variation in the degree of cementation add to the complication in numerical modeling. In this study, the applicability of two existing t-z models, developed for Florida limestone and soft rock, was evaluated based on numerical simulations of three bi-directional load tests conducted at caliche-dominant sites. The corresponding top-down load tests were also simulated for further assessment. A MATLAB-based finite-difference program, NVShaft, has been used to implement the mentioned t-z models in axial load analysis. Complexity originating from drilled shaft construction and the interaction with caliche during one axial load test resulted in a stiffer predicted response compared to measure data. For the other two load tests, both t-z models produced comparable load-displacement responses. It was observed that the t-z model for Florida limestone predicted relatively stiffer responses and higher drilled shaft capacity.

Sep 8, 2021

By Michael G. Batten, Brian D. Keaney

]The Virginia Department of Transportation (VDOT) and the harbors on the James River routinely use precast concrete piles founded in the Yorktown formation to support bridges and other coastal structures. However, axial pile resistances for large diameter piles in this area have been historically overestimated on past projects. This may be due to a common assumption that very large unit end bearing resistance will be developed for a large diameter displacement pile that is driven a significant depth. This assumption is integrated in the Nordlund (1963; 1979) method which is commonly used to estimate axial pile resistance for bridge foundations. A static and dynamic pile load testing program was implemented as part of the Hampton Roads Bridge and Tunnel Expansion project in Norfolk, VA in the James River. A primary objective of this program was to calibrate an axial resistance calculation method against the measured load test results. A method developed by Eslami and Fellenius (1997) that uses CPTu data directly was effective at calibrating to the measured load test results, and allowed for clearer interpretation of the unit resistance values than indirect, semi-empirical methods that require interpretation of soil friction angle and undrained shear strength.

Sep 8, 2021

By Dominik Gächter, Wojciech Szczepiñski

In early 2020, the construction phase began for the new complex of buildings for Radium Hospital in Oslo – the leading facility for cancer treatment in Norway. Settlements in the surrounding area, caused by pore pressure changes, allowed for the introduction of an alternative solution for the construction of the excavation pit. The presence of solid bedrock and sensitive clay – the same material that causes major landslides in the Scandinavia – in the excavation pit, lead to a combination of techniques, which were never applied in Norway before. For the stabilization of the clay Dry Deep Soil Mixing was applied to allow safe execution of the geotechnical works. Interlocking Bored Piles with footbolts and Jet Grouting columns, in combination with anchors, provided the retaining structure for the excavation pit. Rock injections were performed to avoid any ground water ingress into the pit. Underpinning of fully operational, adjacent buildings was carried out with jet grouting columns. These works were performed from the basement of the hospital and the ‘ACI – Acoustic Column Inspector’ was used to ensure proper installation of 2 m diameter columns to a maximum depth of 25 m. The buildings were later founded on Steel Core Piles, the most common pile type in Scandinavia.

Sep 8, 2021

By Challa Venkata Rami Reddy, Anindya Roy, G. R. Konni

This paper presents the results of pile lateral capacities obtained from both conventional design and fullscale pile lateral load tests. Conventional design using P-Y curve analysis is very commonly being used by designers; designers use well accepted software programs like Lpile and Allpile for analysis. However, these programs do not cover the soil models to simulate engineering behavior of marine carbonate sands; which generally have different engineering behavior than silica/quarts sands. In this study, the existing soil models for common sands have been used to assess pile lateral capacities and these results are compared with the results from full-scale instrumented pile lateral load tests performed in compacted marine carbonate sand fills of artificial island constructed for oil and gas facilities in Abu Dhabi. The objective of this study was to verify the applicability of the existing sand soil models for carbonate sands and also to verify the associated conservatism in the pile lateral capacities. This study shows that the actual pile lateral response is much stiffer than what was anticipated through the LPile analysis. Therefore, further research focus may be required to capture the engineering behavior of the marine carbonate sands to develop specific P-Y curves.

Sep 8, 2021

By Ralphie Adams, Tiana Rasmussen, Ashley E. Shirer

Transmission line foundation designers must rely on limited subsurface information, from easily accessible locations, resulting in subsurface uncertainty, increased design risk and increased construction costs. This paper presents a different approach for foundation analysis conducted in mountainous and alluvial floodplains located northwest of Phoenix, AZ. The region is dominated by fault-bounded, northeast dipping mountain ranges, where rock types and drillability can vary from granite to intact basalt. The valleys between are comprised of “basin-fill” deposits ranging from conglomerates and cemented soils to lose alluvium. Recently deposited alluvial fills can vary in depth significantly from location to location due to erosion and deposition from active and historic hydraulic features. To limit the subsurface uncertainty for foundation design, a phased approach using geophysical surveys along with detailed geologic reconnaissance was employed. Both compression wave and shear wave velocities were measured in order to identify the depth and properties of loose erodible materials from more scourresistant cemented, conglomerate, and rock deposits. These analyses were used in combination with limited subsurface drilling and sampling to evaluate direct embedment steel pole foundations for over fifty structures. Post analysis results from limited construction drilling reports were used to assess this approach.

Sep 8, 2021

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

By Brandon M. Robinson, Osman F. Besler, Dominik Gaechter

With the increase in population over the last decade, and anticipated population growth over the coming years, Norway is making significant investments in the Country’s infrastructure. Part of this investment in development starts with the Intercity development project in South-East Norway, which is the largest transport project in Norway. The Intercity Development project consists of 270 km (167 mi.) of new doubletrack rail, capable of train speeds reaching 250 km/h (155 mph). The new stations are centrally located in the major cities, in South-East Norway, to provide the benefit to as many citizens as possible. The goal of the project is to reduce the increase in traffic, which is coupled with an increase in population, and reduce the travel times between the cities. The Intercity Development Project has an anticipated completion date of 2034. The Sandbukta-Moss-Såstad (SMS) project, part of the Intercity development, includes 10 km (6.2 mi) of new double-track railway and is situated on the Østfold Line, near the city of Moss, Norway shown in Fig. 1. The 10 km SMS-section covers three open stretches and two tunnels, including 630 m (2,066 ft) substructure for double-track railways on the open line at Sandbukta. The Moss tunnel is a 1720 m (5,643 ft) long tunnel from Sandbukta to Moss center, including a 420 m (1,378 ft) long concrete culvert. The new Moss station includes an 800 m (2,625 ft) long station area. The Carlberg tunnel is a 2350 m (7,710 ft) long tunnel from Kleberget to Carlberg, including a 200 m (656 ft) long concrete culvert.

Sep 8, 2021

By Martin Walker, Joseph Ang, Jongwon Lee, Alvin Bayudanto, Lilian Lorincz, Morteza Khorshidi, Wenyong Rong

This paper presents a case history of liquefaction susceptibility evaluation study for a major infrastructure project in the San José area. The subsurface material of the study area consists of Holocene alluvial deposits composed of interbedded and crosscut clays and silts, sands and gravels. The simplified approach for liquefaction triggering evaluation was carried out using both CPT data and SPT data representing site’s seismic capacity and the peak ground acceleration associated with a return period of 975 years at ground surface representing seismic demands. Site-specific cyclic stress ratio (CSR) profiles as seismic demand are also estimated from one-dimensional site response analysis. The simplified approach uses empirical depth stress reduction factors (rd) based on generic shear wave velocity profiles to account for the non-rigid response of the soil profile in estimating CSR. The CSR profiles of the simplified procedure were examined by completing site response analyses using site-specific soil profiles to represent site-specific seismic demands in the liquefaction triggering evaluation. The paper concludes with a comparison and discussion of the liquefaction evaluation examining results from CPT versus SPT data, and the comparison of CSR profiles from the simplified procedure versus site-specific response analysis.

Sep 8, 2021

By Racquel Nottingham, Marc Mastrantuono, Freddy Lopez

In the digital era that we live in, connectivity and mobility play a decisive role in our daily activities. In this context, insufficient telecommunication infrastructure gives origin to the so called “dead zones” (areas with poor or non-existing cell phone reception), which hinder economic development in small communities and in many rural areas, since they remain invisible to a larger marketplace due to the inadequate cellular coverage. Several countries are working to identify these dead zones and with this information, establish strategies together with mobile providers in order to improve the existing mobile networks by expanding the coverage areas. As a result of the analysis, it is expected that thousands of telecommunication towers for 4G and 5G networks will be erected in the coming years. Telecommunication towers are slender elements that require large shallow foundations to verify primarily the safety against overturning. However in remote areas, it can be advisable to consider alternatives to the conventional shallow foundations, in order to optimize the use of materials (concrete, reinforcement steel, etc.). The following article presents an overview of intervention projects, where telecommunication towers were founded on micropiles. The micropiled foundations allowed to reduce considerably the dimensions of the originally planned shallow foundations. Furthermore, the use of micropiles allows for additional optimization, in combination with pre-fabricated foundations (i.e., precast concrete elements, etc.). This paper will focus mainly on the design and the execution of the micropiled foundation.

Sep 8, 2021

By Abdulazeez Rotimi, Barry Sheppard, Abid Adekunte

Good engineering practice is a function of sound theoretical knowledge, first-hand experience on previous projects of similar scope and scale, good acquaintance with case histories of similar projects completed by others in similar environmental conditions, as well as satisfactory degree of exposure to state-of-the-art methodologies. The four factors itemised above are typically interdependent. They amalgamatively influence the judgement of the Engineer and they ultimately result in the delivery of safe and cost-effective solutions by Professional Engineers. This technical paper presents detailed information on the ground engineering aspects of a large-scale housing development project located on a sloping site that had been presumed to be unstable in West Sussex, England. The ground engineering design package for the scheme comprised of temporary working platform designs & stability assessment for piling rigs and other construction machinery, geostructural designs for approximately 1km total run of permanent bored pile retaining walls to support the split-level construction on the sloping site and geostructural designs for the permanent foundation piles to support the housing units. The paper details how the four factors outlined above were amalgamated by the project’s foundation specialist consultants & piling contractors to deliver safe and practical solutions for the development, with significant savings in materials, cost and project completion time.

Sep 8, 2021

By Arash Saeidi-Rashk-Olia, Dunja Peric

Energy piles are gaining increased popularity due to a growing demand for clean energy. To further advance the understanding of soil-structure interaction in energy piles, recently-derived analytical solutions have been implemented to investigate the impact of stratigraphy on the soil-structure interaction. This was accomplished by comparing the measured and predicted head displacements, axial strains and stresses in an energy pile embedded in the actual homogeneous and layered soil profiles, as well as into synthetic homogeneous soil profiles. The analytical solutions for homogeneous soil profile captured the smooth experimentally observed response versus depth very well. In the case of a layered soil profile, the corresponding analytical model was capable of capturing nuances in trends of axial stress and strain versus depth at the interface of different layers. The analytical predictions for the layered profile appear to be slightly less accurate than for the homogenous profile. The experimental data obtained from the layered profile appear to be a bit more scattered than those from the homogeneous profile. In the former case, the interplay of the individual soil layers with the pile occurs while maintaining the continuity of the pile stress and displacement at the interface of different layers. The response throughout each layer of the layered profile is quantitatively different than the corresponding homogeneous response. Nevertheless, qualitatively the response throughout each layer of the layered profile is similar to the response of the pile embedded in the corresponding homogeneous layer.

Sep 8, 2021

By Nozomu Kotake, Rakshya Shrestha, Ralph Griffin, Stefanos Papadopulos, Jeff Fippin, Sushil Kafle

Direct Power Compaction (DPC) is a deep Vibro-compaction method used for liquefaction mitigation. In DPC, H-beams are used as vibrating rods penetrating deep into the ground, and a vibrating force is applied directly to the tip of these H-beams to densify the loose ground. A characteristic feature of DPC is the use of a flapping plate installed at the base of the H-beam to enhance the compaction efficiency during penetration. In addition, 2-rod and 4-rod type equipment have been developed to improve productivity and enable rapid construction. DPC was selected as the most suitable and cost-effective technique to mitigate liquefaction hazards in two projects in the San Francisco Bay Area, one on Alameda Island and another on Treasure Island. Both sites were capped with hydraulically placed sand fills. Liquefaction analyses indicated excessive liquefaction-induced settlements and large lateral spread without ground improvement. Densification using DPC was performed up to depths of 42 ft to reduce the liquefaction potential of the sand fill to acceptable levels and to allow planned improvements. Cone penetration tests were conducted before and after DPC to evaluate its performance. This paper describes the equipment and process involved in DPC and discusses its application in terms of subsurface conditions and geotechnical design considerations.

Sep 8, 2021

By Patrick Granitzki, Alicia Plinio, Janitha Batagoda, Peter Howell

The City of Newark is making a comeback with new mixed-use multi-storied Residential Development projects. The majority of developers tend to use driven H-pile deep foundation systems to support their super-structures. A different approach was recommended for one particular new development near the Passaic River. The surficial geology included glacial deposits consisting of loose to dense sand overlaying relatively soft silt and clay and a lower stratum of medium-dense sand. During a preliminary site investigation for the project, bedrock was encountered at depths ranging between approximately 168 feet to 182 feet below the ground surface. Design capacity required a single pile of 200 tons. Two different pile foundation systems were evaluated in conjunction to the typical driven H-pile system in order to review potential costs and construction schedule impacts. The two alternative pile systems evaluated were tapered tube piles and drilled displacement piles. Theoretical calculations were followed by in-situ load testing. The field testing results indicated the use of drilled displacement piles as the best option for a portion of the proposed building. This paper discusses the different piles systems considered, installation and using drilled displacement piles to minimize cost and optimize construction.

Sep 8, 2021

By Gisele R. Passalacqua, Taylor Malangone, Subhash Mahali

New York City is a busy metropolis with 8 million people. New York has the largest public transportation system with 6 million riders a day throughout the subway system. Keeping this infrastructure in service is vital to the overall economy of the region. Hurricane Sandy proved to have a devastating impact on infrastructure in Metropolitan New York. New York City Transit is on the forefront to provide resiliency and maintain its facilities with the use of flood protection systems. This paper presents flood protection structures utilized at Hammels Wye substation site in Far Rockaway, Queens, New York. The site is in close proximity and surrounded by water. The subsurface conditions consist of loose silts overlain by medium dense glacial sand. The high groundwater level combined with limited access to the site presented challenges. A flood protection system consisting of flood walls was recommended for this site. In certain areas the flood walls consisted of retaining walls supported on micropiles. For other areas, the flood walls consisted of steel sheet piles with jet grout columns to reduce seepage below the walls. The effect of driving sheet piles with vibratory hammers on nearby existing structures is always a concern. Recently, hydraulic hammers with variable moment/frequency are being considered as a mean to reduce vibration effects during driving. In this project, an instrumentation testing program was performed to measure peak particle velocity during sheet pile driving utilizing the variable moment vibratory hammer. Plots of peak particle velocity versus frequency were generated. This paper will present the design aspects of the flood walls and construction challenges during installation. This will prove beneficial to engineers in both design and construction fields.

Sep 8, 2021

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 Dharmil S. Patel, Zoyav S. Benyaminov, Cassandra A. Wetzel

Rehabilitation of the Henry Hudson Bridge is nearing completion, connecting Spuyten Duyvil in the Bronx to Inwood Hill in Manhattan, New York. Constructed in 1936, the Henry Hudson Bridge spans 840 feet over the Hudson River. Challenging geotechnical aspects of this Project required a team of innovators to overcome. Rehabilitation of the existing bridge involved the replacement of sixteen bent pedestal substructures, two abutment pilasters and installation of new deep foundations at the skewbacks. However, the Bridge, roadways, adjacent Metro-North Railroad (MNR) structures and New York City (NYC) Parks land were to remain open to the public for use, with minimal disturbance. In addition to physical constraints, geologic site conditions varied widely across both sides of the River, with varying bedrock quality and depth, greatly impacting the proposed design and construction. Extensive analysis of bedrock conditions was conducted to locate areas of potential wedge failure. The implementation of anchors was used to reinforce rock stability where pedestals and pilasters were replaced. This paper describes several challenging technical and natural aspects overcome in the rehabilitation of the Henry Hudson bridge foundations, including varying geologic site conditions, access restrictions, construction limitations, project specifications and design requirements.

Sep 8, 2021

By Matthias Pulsfort, Hanna Nissen, Markus Herten

An insufficient integrity of cast in-situ bored piles can lead to a reduction of the load bearing capacity and may require cost intensive repairs. Reasons for an insufficient pile integrity are linked to the construction process, mainly to poor concrete quality leading to bleeding and segregation of the fresh concrete. Moreover, the entrapment of soil and an insufficient concrete cover can pose a problem. Knowledge about the time-dependent development of the fresh concrete pressure during the construction process of bored piles is needed for a better understanding of the underlying processes causing these defects. Therefore, pressure measurements were carried out on different construction sites with pressure cells being installed at different depths along the reinforcement cage. The measurements revealed the maximum pressure acting on the surrounding soil. The achievement is a better understanding of the effects of the concrete placement specifically and the construction process in general on the surrounding soil to reduce the risk of pile imperfections.

Sep 8, 2021