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By Mario Mauro

In 2007 the US Army Corps of Engineers classified the Herbert Hoover Dike in Florida as a Dam Safety Action Classification (DSAC) 1 dam, and started the implementation of one of the largest dam rehabilitation projects in the nation. The construction of the cutoff wall is a key feature of this rehabilitation work to upgrade the dike to current dam safety criteria. The cutoff wall installation is currently being completed on Reach 1, which extends from Port Mayaca to Belle Glade, under a Multiple Task Order Contract based on performance specifications and stringent verification criteria. For the construction of the cutoff wall TREVIICOS selected the self-hardening slurry method. Since the cutoff wall is installed through a layer of highly variable limestone with Unconfined Compressive Strength (UCS) up to 14,000 psi, the excavation requires the use of the hydromill equipment. This is the first successful application of the hydromill technology with self-hardening slurry in a large scale project in the US. This paper presents the details of the method utilized, the quality control procedures, and the experience gained over seven miles of cutoff wall installed.

By Giovanni A. Bonita, Asher H. Peltz, Sean D. Johnson

This paper examines a complex earthwork project in the Washington DC metro area that had project delivery directly impacted by questionable instrumentation monitoring data. The case study summarizes the impacts to the project caused by questionable instrumentation data and reveals how the authors were able to utilize data to extract meaningful insights. The case study also demonstrates how clear data presentation became a key factor in maintaining stakeholder trust and facilitated progress of the project schedule. The case study highlights key points to collecting high quality instrumentation data, approaches to assess and improve value of the data collected, and techniques to reduce and interpret questionable data.

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 Akshay Sakhuja, M. S. Karthika, R. Vignesh

"The bridge across River Mandovi in Goa is a cable stay bridge structure proposed parallel, along existing bridges for regulation and reduction of vehicular traffic; the entire bridge structure is supported on pile foundation socketed in rock. This paper describes drilling related issue encountered during execution of pile where bed rock varies considerably from factual geotechnical investigation, which in turn affected the productivity of bored piles socketed in rock then chiseling is advocated for rock socketing with limited number of blows based on penetration resistance of rock encountered or equivalent energy principle to increase the productivity and also to avoid excess chiseling which otherwise would have fractured the rock mass below and around the pile tip resulting in increased settlement of pile subjected to design load. Contractor decision on socket length have been taken without compromising either quality or productivity; the paper presents various procedures and the equipment involved for installation of pile in rock along with the conclusion related to termination of pile in rock and also the lessons learned in process.INTRODUCTIONPile foundations are generally used to transfer heavy loads in deeper bearing stratum if the soil immediately beneath the base of the foundation does not have sufficient capacity. The bridge across River Mandovi, Goa is in its construction phase as a part of the development plan of Goa State Infrastructure Development Corporation Ltd (GSIDC). The project was awarded to M/s. L&T Construction, Heavy Civil Infrastructure; subsequently the geotechnical investigation was awarded to M/s L&T Geostructures.The client has specified the foundation of the bridge as rock-socketed. Rock socketing is generally done to achieve higher bearing pressure through concrete-rock shear interface which many building codes permit. The design and construction of rock socketed pile foundation entails a detailed analysis and judgement on the superstructure loads, predominant geological conditions as well as ground water levels. The termination of pile is normally based on thumb rule of half to three times the pile diameter into the rock. Quite often the criteria is based on chisel penetration rate (Gandhi,1990) In fact, this is the key factor to consider appropriate and economical depth of embedment of pile into rock stratum which necessitates enormous understanding on the type and quality of rock strata encountered which may significantly influence the selection of suitable rotary rig for pile installation. Such criteria are site specific and also applicable for the set of equipment used for the particular project."

Jan 1, 2015

By Andreas Brandner, Karl Schoenherr-Strasse, I. B. Brandner, Dipl. Ing

"A world famous Wintersport resort in the Alpine planned to build a parking garage for more than 600 cars and busses situated between a torrent, a district road and the village.A nearly 200 m long building giving place for 6 parking levels and a maintenance level for busses and trucks is situated alongside a hill causing excavation height between 20 and 25 meters, which had to be secured. Due to restrictions – neighbours did not allow the client to drill anchors for retention – we designed a solution combining micropiles, strand anchors, shotcrete and nails as permanent earth retention not exceeding the space of 7 meters provided by the local street. Soil conditions were as challenging - reaching from backfill to moraine with boulders of more than 20 m³ volume – as the construction period of total 12 months for the whole project, which was opened mid of November 2015.The innovative solution outperformed the client´s project from the technical and commercial aspect and helped the contractor to save time and money.The design process with its difficulties as well as erection process is described in the following paper."

Jan 1, 2016

By Fabio Santillan, Lyndon Bedford

"This paper presents the main features of the Wolf Creek Dam Foundation Remediation Project, highlighting the innovative construction approach and stressing on how the collaboration between the contractor and the owner became a key element for the success of this project.The main rehabilitation contract, $341 M, was awarded in 2008 for the construction of a 980,000 sqft concrete barrier. Most of this 2ft-wide concrete barrier wall is being built to depths reaching 277 ft using innovative construction techniques proposed by the contractor and under quality control measures that exceed by far the industry standards.The construction of the barrier wall entails the use of nine different foundation techniques which run concurrently following very stringent requirements in terms of verticality, distance between open elements, strength, permeability and dimensions that control the installation sequence of each barrier wall element.The innovative construction approach by the contractor and the collaborative efforts by the contractor and the USACE (“US Army Corps of Engineers”) have brought this unique and very difficult project to a successful completion, setting new standards in the dam foundation industry and nine months ahead of scheduleINTRODUCTIONWolf Creek Dam is on the Cumberland River in south central Kentucky. It provides hydropower, flood control, water supply, and water quality benefits for the Cumberland River system and surrounding region. The lake is a source of recreation that has attracted more visitors (4.89 million) than Yellowstone National Park (2.87 million).The dam and its adjacent reservoir reside upon a heavily Karst bedrock foundation. In late January 2007, the USACE placed the dam under a 'high risk' for failure designation. As a temporary measure, the pool elevation was lowered to 680 ft Above Main Sea Level (“AMSL”), 80 ft below its maximum capacity, with huge impacts to the local economy while the major, and ambitious, $ 594 million remediation program to bring the dam back to its full operating condition was carried out.The main rehabilitation contract of $341 million was awarded in 2008 for the construction of a 980,000 sqft concrete cut-off barrier. Most of this 2ft-wide concrete barrier wall has been built to depths reaching 277 ft using innovative construction techniques under quality control measures that far exceed the industry standards."

Jan 1, 2015

By Jianhua Wang, Jianming Yao, Zhen Meng, Jinjian Chen

"Drilled screw pile is a newly developed displacement pile foundation which has been applied in soft clay for many years. Compared with traditional circular displacement pile, It is characterized by high bearing capacity, small volume and small squeezing effects. For the purpose of investigating the squeezing effects of drilled screw pile, a full scale field monitoring test with two test piles was performed. Detailed soil horizontal displacement and pore pressure measurements were conducted in the vicinity of the two drilled screw piles during penetration and subsequent soil consolidation. It can be concluded that the horizontal displacement of the surrounding soil induced by the installation of a drilled screw pile is mainly in a circular region with a diameter of 3 m (r/D<6), and the compaction effect outside the area can be essentially negligible; The excess pore pressures measured at the same time increase with depth throughout the entire process of consolidation, and its dissipation shows an exponential decay as a function of time.INTRODUCTIONA knowledge of the displacement and stress changes induced in the soil surrounding a pile is very important for evaluating pile performance. Numerous field and laboratory research projects have examined loading conditions, total soil stresses, and excess pore pressures during and following pile installation (Pestana et al., 2002). A relatively comprehensive and detailed review of these experimental works from 1948 to 2002 was presented by Pestana et al. (2002). More recently, Xu et al. (2006) conducted a field experiment to study displacements and stresses in the vicinity of two pipe piles during their installation in a soft lightly overconsolidated clay and compared the field measurements with existing predictive methods. Abdrabbo and Gaaver (2011) collected field observation data from four different construction sites to study soil disturbance during construction of piles using continuous flight auger (CFA). They have found that the disturbed zone of soil by CFA has a conical shape and the excess pore pressure has no appreciable influence on the load capacity of the piles.Drilled screw pile (DS pile) is a kind of vibration-free, cast-in-place concrete pile. Because of the excellent bearing performance, low level of vibration pollution and negligible spoil, as well as its fast construction speed, DS pile has been widely accepted by many engineers around the world. As a new type of drilled displacement pile, the significant installation effects of DS pile on the adjacent soil have not been systematically and integrally investigated yet. Since a proper numerical simulation of the real installation process of DS pile is difficult to achieve, the investigation based on field measurements is necessary. This paper presents a field investigation of the installation effects of two DS piles on surrounding soils. Detailed horizontal soil displacement and pore pressure measurements during pile installation and subsequent soil consolidation have been conducted. Based on the monitoring data, variation of horizontal displacements and dissipation of excess pore pressures with depth and time have been analyzed. What's more, the construction machinery and technology used in DS pile installation are also simply introduced."

Jan 1, 2015

By Hamed Layssi, Farid Moradi, Thomas Tingson

This paper describes the feasibility and pilot study of of using existing non-destructive testing solutions for evaluating structural integrity and mechanical performance of mass concrete foundations. This paper includes two pilot studies using well-known NDT methods (i.e., Crosshole Sonic Logging and seismic tomography) for new applications (i.e., NDT inspection of mass concrete foundations). In the first case, we will examine an existing mass concrete foundation block with internal cracking, which has negatively impacted the strength and stiffness of the foundation block. A combination of pulse velocity and 2D tomography was used to evaluate the structural integrity in the foundation block. In the second case, the quality and integrity of newly built mass foundations were evaluated using Crosshole Sonic Logging (CSL). The methods are combined to locate potential sub-surface defects such as large voids and discontinuities. This paper aims to study the effectiveness of the NDT methods of Deep Foundations to assess the quality and structural integrity of new and existing mass foundations and explore the opportunity to extend the capabilities of these tests beyond their conventional use.

Sep 8, 2021

By Richard J. Hartman

This presentation identifies some of the more common problems associated with cofferdam construction. After the various problems are identified, they are briefly explained and possible solutions and preventive measures are noted. Photographic slides used during the seminar illustrate the conditions. This discussion is limited to cofferdams which are braced structures excavated inside to allow access for construction. The common procedure is to drive sheet piling and then alternatively install bracing and excavate. They can be located either on land or in water. Loads are applied by soil, water, surcharge pres-sure, eccentricities, and impact loads. The loads are resisted by the sheet piling, the bracing, and the soil below the bottom of the excavation; each of these three components must be capable of resisting the applied loads.

Jan 1, 1987

By Arash Khosravifar Ph. D. P. E., Thomas Torkelson P. E., Milad Souri Ph. D. P. E.

Kinematic demands from lateral ground deformations can be a major cause of damage to maritime and highway transportation structures such as wharves, piers, and bridges. These kinematic demands are different from the ground deformations in the free field in that the resisting forces from piles will reduce the ground deformations to some extent (i.e., pile pinning effect). Current design codes for wharf structures allow the beneficial resisting forces from pile pinning effects to be incorporated in pseudostatic slope stability analysis (e.g., ASCE/COPRI 61-14). While design guidelines that are specifically developed for bridge foundations provide recommendations on how to incorporate the pile pinning effects (e.g., Caltrans 2012), their applicability to wharf structures need to be evaluated. This study uses the results of a large-scale centrifuge test on a pile-supported wharf structure to evaluate the accuracy of available Newmark sliding block analysis in estimating the lateral ground deformations. Pile pinning effects are incorporated based on the approach outlined by Caltrans. The results of this study support the use of existing pile pinning methods that were primarily developed for bridge foundations in maritime structures (e.g., wharves and piers). It was found that median Newmark displacements provide a good estimate of the permanent end-of-shaking displacements and that the median plus 1 standard deviation Newmark displacements provide a good estimate of the peak transient displacements. Design considerations for use in the Newmark sliding block analysis to estimate the kinematic demands on piles are discussed.

Oct 1, 2022

By Adam Gerondale, David Hemstreet, Lisheng Shao, Kenji Yamasaki

"Foundation soils of a proposed single-span bridge over a busy railroad in Anchorage, Alaska included a layer of sensitive, non-plastic to low-plasticity silt. Slope stability analyses showed that, without ground improvement, the proposed abutments would not be stable immediately following the design earthquake due to the liquefaction of the sensitive silt. Wet soil mixing was selected to mitigate the liquefiable soils and assure abutment stability because: (i) it is a non-vibratory method and can be used for areas adjacent to the railroad tracks and underground utilities, as well as in areas not sensitive to vibration; and (ii) preand post-ground improvement testing, such as SPT or CPT, is not required. Eliminating the liquefaction hazard at the site also allowed for the abutments to be economically supported on shallow spread footings. A total of 511 soil-cement columns were constructed at the two abutments, each with a diameter of 8 feet (2.4 m) and an average length of 20 feet (6.1 m), extending from about 30 to 10 feet (9.1 to 3.0 m) below finished ground elevation. The columns were laid out in a shear wall pattern (in the longitudinal direction of the bridge) to increase stability under the loading by approach embankments.INTRODUCTIONAlaska Department of Transportation and Public Facilities (Alaska DOT&PF) is currently constructing West Dowling Road Overcrossing in Anchorage Alaska. It will be a single-span, steel box girder bridge approximately 200 feet (61 m) long and 100 feet (30 m) wide. It will have approach embankments, about 40 feet (12 m) high, on both sides. It will carry the new extension of West Dowling Road over double tracks of Alaska Railroad and Arctic Blvd. Foundation soils of the abutments consist of surficial fill and peat layer underlain by soft silt which is likely to liquefy and lose strength under shaking by a design earthquake. Both deep and shallow foundations were considered to support the bridge abutments. The design team pursued the option of improving the foundation soils and using shallow footings. Several ground improvement methods were evaluated, out of which wet soil mixing was selected as the best option.In situ wet soil mixing (hereinafter simply soil mixing) is mechanical mixing of soil in its location with cement slurry and produces soil-cement (soilcrete) columns that are stronger, less permeable, and less compressible than the original soil. Soil mixing is used for various applications including reinforcement of soft soils, excavation support, liquefaction mitigation, cutoff walls, etc. This paper presents a case history of soil mixing successfully used to improve foundation soils of bridge abutments to allow the use of spread footings."

Jan 1, 2015

By Takefumi Takuma, Hiroyuki Nishimura, Shigeru Kambe

"In order to achieve tubular pile driving with low noise and low vibration, the Press-in Piling Method has been adopted on many projects. The method utilizes reaction force derived primarily from previously driven piles to push in the next pile into ground. With attachments, the Press-in piling equipment can deal with hard soil as well as difficult site conditions. At West Toronto Diamond Rail Grade Separation Project in Toronto, Canada, the Press-in piling equipment drove more than 500 of 914 mm (36 inches) diameter tube piles in length of 12 to 25 meters (39 to 82 feet) to construct earth-retaining walls for railway grade separation. Myoshoji River Restoration Project in Tokyo, Japan drove some 600 of 1,000mm (39.4 inches) diameter tube pipe sections in length of 11 to 22 meters (36 to 72 feet) by the rotary Press-in piling equipment to increase the flood drainage capacity of an existing river in highly populated area of the city. Both projects exemplify the advantages of the method in urban settings.1. BACKGROUNDThe Press-in Piling Method was invented some forty years ago in Japan, where a very large number of construction projects were causing widespread construction pollution, especially by pile driving work in densely populated areas. The method has been providing solutions for piling projects which could not have been built otherwise due to the noise and vibration impact to the surrounding communities. The method can be used with various types of piles including sheet piles, tubular piles, concrete sheet piles and so on. With high pressure water jet and continuous flight auger attachments, the Press-in piling equipment can deal with dense sand, stiff clay, gravels, boulders and even soft rock without employing a different set of equipment."

Jan 1, 2015

By Christian B. Woods, Joe C. Drumheller

"Kenneth A. Huber, P.E., Langan Engineering & Environmental Services, New York, New York, USAThe dream to bring New Jersey Devils hockey to the largest city in New Jersey became a reality in the summer of 2005, when construction began for the Prudential Center in downtown Newark. The Prudential Center site encompasses an entire city block that had a varied history of uses ranging from a cemetery in the late 18th century, to a rail yard and train station for the now-defunct Central Jersey Rail Road in the 19th and early 20th centuries, to commercial development in the latter half of the 20th century. Each of these prior uses presented challenges to the design and construction of the Prudential Center that required innovative engineering solutions, including: archaeological investigation and exhumation of the former cemetery occupants, protection of historic buildings surrounding the site, and extensive demolition to remove old train bridge foundations.The design team was required to develop potential foundation systems for the arena. Several foundation concepts were evaluated for cost and constructability, including: driven piles, drilled shafts, and shallow foundations on improved subgrade. Following a detailed cost analysis and value engineering exercise, the decision was made to support the arena on spread footings following the completion of a multi-phased ground improvement program consisting of a combination of dynamic compaction and removal and replacement. To evaluate achievable allowable bearing pressure as part of the design, a dynamic compaction test section was performed within the building footprint prior to the start of production work; this resulted in an increase of the allowable design bearing pressure from 2 tons per square foot (tsf) to 3 tsf. This reduced the expected foundation costs by 30% and gained sufficient time in the schedule to allow for the completion of the arena in time for the New Jersey Devils 2007- 2008 hockey season.BACKGROUNDThe dream to bring New Jersey Devils hockey to the largest city in New Jersey became a reality in the summer of 2005, when construction began for the Prudential Center in downtown Newark. After several years of negotiating between the City of Newark, local landowners, area developers, and the Devils themselves, a deal was finally struck to erect Newark Arena, now known as the Prudential Center, right next to City Hall. This is not to say, however, that once the site location was finalized, that no further challenges were encountered in the construction of Newark’s new crown jewel."

Jan 1, 2015

By Ke Yang

"Drilled shafts are typically used to support structures subjected to large moments at the shaft head. The large moment can produce push and pull forces on the two sides of a drilled shaft. Consequently, the applied moment is partially resisted by the push-pull moment resistance induced from the vertical side shears. This type of push-pull resistance has not been fully recognized in most design and analysis methods. In this paper, a 30 finite element model for a drilled shaft subjected to lateral load and moment is presented and is validated against two field lateral load tests. Based on the 30 finite element model, a parametric study is carried out. It shows that the push-pull moment can resist 18-35% of the applied moment. The parametric study also shows that the push-pull resistance varies linearly with loading eccentricity when the eccentricity is less than the shaft embedment length. A method to estimate the push-pull resistance is proposed based on the results of the parametric study. Then, a new method for lateral capacity prediction is proposed to account for the push-pull resistance. The base shear resistance is significant for short drilled shafts; therefore it is also included in the proposed method. A case study on four lateral load field tests illustrates that the new method could improve the accuracy of lateral capacity prediction when compared with the traditional Broms method.INTRODUCTIONDrilled shafts are typically used to support a variety of structures subjected to large moments. Sound walls, highway signs, traffic signals, high-rise buildings, electrical transmission towers, and bridge piers are examples of cases where lateral loads with large eccentricity would result in high overturning moments on foundations.Current analysis methods for capacity predictions (Broms, 1964a and 1964b; Brinch Hansen, 1961) or deflection predictions (Reese, et al. 197 4) of laterally loaded drilled shafts are based on the lateral resistance of soils and rocks. However, O'Neill pointed out that moments can be partially resisted through the push-pull resistance provided by the vertical side shears due to the rotation of the pile (Reese, 1997)."

Jan 1, 2005

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

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

Oct 1, 2022

"What can we do in ground engineering to reduce damage to the environment, to repair historic pollution, to reduce our demand on basic resources and to reduce the carbon footprint of our industry? Some developments in geotechnical engineering are already heading in the right direction. These include reductions of ground pollution from grouting, improved dewatering procedures and advances in mix-in-place processes, ground improvement and jet grouting.There is increased interest in certain promising technologies (for example, drilled partial or full displacement piles), but this approach remains for the moment somewhat avant-garde. These piles require substantially greater power to install, and the overall sustainability balance for general application has yet to be shown to be in their favour. They are particularly suited to polluted sites where the problem of dealing with spoil would be costly and where, in the past, driven cast in-situ piles would have been employed. Drilled displacement piles offer some environmental benefit over driven piles in that they cause far less drawdown of potentially contaminated near-surface ground into sensitive, underlying aquifers.There is also great interest in various means of increasing the frictional capacity of bored piles, both conventional auger and continuous flight auger (CFA) piles, by threading or ribbing the soil/pile interface. The increase in adhesion capacity allows reduction in the pile dimensions necessary for a specific load. This obviously leads to less construction waste, but also to less permanent material consumption in the piles and also in the pile caps.The role of ground improvement remains significant for brown land sites and lower capacity foundations. Information technology (IT) has improved the quality assurance of stone column construction, for example. From the sustainability point of view, this is a good news method; here is no cement, no pollution and little obstruction to future redevelopment. We now need to introduce recycled crushed materials instead of natural aggregate as general practice and the technique’s green credentials will be really compelling."

Jan 1, 2009

By Remco Offenberg, Marcel Bielefeld, Martijn van Delft

The question of the continued suitability of existing foundations arises when the function of the superstructure changes. This can occur when the superstructure is replaced or when the existing structure is expanded, leading to higher loads on the existing foundation. Quite often it is a challenge to define the suitability (with respect to integrity, bearing capacity or both). The lack of information on the existing foundation (such as pile dimensions, installation records, original soil investigation, design calculations, etc.) makes it frequently seemingly impossible to assess whether the foundation or foundation elements can be re-used. The paper outlines the tools available to an engineer to evaluate existing foundation piles for potential re-use. The paper illustrates the application of these tools through a few case studies from The Netherlands, including the evaluation of a 400 years old bridge foundation to address increasing traffic loads.

May 1, 2022

By Babak Mamaqani, Pirooz Barar

The Moanalua trestle spanned over Moanalua Stream, Honolulu, HI and was designed to accommodate construction of five 10 feet diameter cast in drilled hole (CIDH) piers as a part of Honolulu Authority for Rapid Transportation (HART) project. Due to the proximity of piers to the existing bridge, the trestle was elevated 20 feet above grade. Stratigraphy of the site consisted of shallow depth of fill and 150 feet of loose to very loose recent alluvium (soft clay) underlain with stiff to hard old alluvium (stiff clay). CIDH casings were installed by a rotator or oscillator depending on the diameter of the piers. The challenge was to design the trestle, not only for heavy gravity loads, but also to resist significant lateral loads from rotator and oscillator with minimal deflection. Series of piles, called reaction piles, were integrated into the trestle at each CIDH pier location to provide adequate lateral support for the rotator/oscillator. Due to the lack of information regarding soil Young’s modulus (E), a methodology was developed to calibrate and calculate E with two methods. Extensive analyses using LPILE and finite element analysis program, PLAXIS, were performed to model reaction piles and calculate lateral deflection. PROJECT SPECIFICATIONS The Honolulu Rail Transit includes 20-mile route and 21 stations to be built from East Kapolei to Ala Moana Center, with $1.55 billion construction budget. The project is divided into two phases as shown in Fig. 1: Phase 1 which connects East Kapolei to Aloha Stadium with expected operation in late 2020, and Phase 2 which connects Aloha Stadium to Ala Moana Center with expected operation in 2025.

Jan 1, 2019

By Michael Perlow Jr

A modification of the original Davisson Offset Limit (DOL) is presented for drilled foundations using soil quake (QDOL) factors ranging from 2 to 6. A further modification of the Davisson Offset Limit has also been developed using helical pile soil quake values (HDOL) based upon helix diameter. In addition, the initial tangent slope (IS) of the pile load test displacement curve is used in lieu of the calculated elastic slope (ES) to eliminate many of the uncertainties associated with determining the drilled foundation pile elastic modulus. The QDOL and HDOL load test methods do not require any graphical interpolation and provide easy simple ultimate pile capacity interpretation methods where drilled foundation pile load tests are not carried to plunging failure. Drilled foundation and helical pile load test case studies are presented to demonstrate the use of the modified soil quake QDOL and HDOL Methods.

By Chris Leach, Lucie Spencer

This case study describes the geotechnical aspects of the basement construction for a multi-storey, residential and hotel complex located in the newly developed Elizabeth Quay precinct in Perth, Western Australia. The development included a three-level basement for car parking covering the full site area which was constructed using the top-down construction sequence. Soil conditions generally comprised 2m of fill overlying medium to dense clayey sands that in turn were generally overlying a very stiff clay stratum at approximately 13m depth. Bedrock level was generally encountered at approximately 22m to 35m below ground level. The ground water table was at a depth of approximately 1m below the existing ground surface level. A site boundary basement wall was constructed using a diaphragm wall retention system. The majority of the vertical loads from the building were transferred to the Kings Park Formation (KPF) bedrock through the use of foundation piles constructed by the CFA method. The CFA piles were installed from existing ground level, resulting in approximately 9m sacrificial concrete length from pile platform level to basement 3 (B3) level. The permanent column loads are such that a single CFA pile was not structurally adequate. To allow a full CFA foundation system to be adopted, an innovative design and construction approach was developed for these heavily loaded columns. This paper discusses the site technical details and the design and construction aspects required to meet the challenges offered by this project.

Nov 1, 2022