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By George J. Tamaro

The design and construction of foundations in the New York City area are usually dictated by the widely varying geologic conditions encountered in the five boroughs, particularly along the spine of Manhattan Island. Rock extends well above sea level at the northern reaches and falls to depths in excess of 250 m at the barrier islands at the southern extremities. These highly variable geologic conditions, significantly affected by glacial activity, dictate different design and construction approaches throughout the five boroughs of New York City. Extensive rock removal is required at the north while long piling is dictated in the south. Similar changes can occur within a project site on Manhattan Island. This paper will describe these conditions in general, will identify the various solutions used to solve these problems and will summarize various foundation types used in the New York City area.

Jan 1, 2000

By Ali Nasirian Ph. D., Gabriel Carvajal

To facilitate the safer and more secure transportation of inmates from San Diego Central Jail to the new San Diego Courthouse, the County of San Diego committed to building a new transfer facility as part of the downtown developments. The transfer facility includes a three-story underground structure adjacent and connected to the Central Jail and a 60-ft deep, 23-ft diameter, 320-ft long tunnel. The tunnel starts at County Jail, passes underneath Western Regional Detention Facility (Old Jail) and, ultimately, connects to the State Courthouse. Condon-Johnson & Associates, Inc. (CJA) was selected to install the temporary shoring shaft for the underground structure as well as three arrays of canopy pipes to support the tunnel’s Sequential Excavation Method (SEM) construction. CJA installed the rectangular 56-ft deep access shaft shoring with three levels of bracing, and a combination of secant piles, soldier piles, and timber lagging. The shoring also included a sliding bridge at top to provide access for trucks to enter and exit from county jail during the duration of construction. Following shoring and shaft excavation, CJA installed and grouted 7-5/8” dia. canopy pipes in 3 reaches, parallel to the longitudinal design line of tunnel with a slight lookout angle. CJA installed 24 each canopy pipes, 99-ft from face of shaft at reach 1, 21 each, 80-ft length canopy pipes at reach 2, and 21 each, 75-ft length pipes at reach 3. CJA confirmed canopy pipe alignment via Inertial Sensing Gyro. To mitigate the possibility of settlements caused by the tunneling operation underneath Old Jail strip footing and grade beams, CJA also performed void fill grouting. Sleeve port grout pipes (SPGP’s) were installed inside the Old Jail basement and grouted with the use of packers as the tunneling operation passed underneath the Old Jail. In detailing various aspects of the construction, this paper aims to magnify the innovative solutions for shoring, canopy pipe installation and void fill grouting challenges as well as the state of the art quality control measures undertaken by CJA.

Oct 1, 2022

By EFFC/DFI Concrete Task Group

Concrete technology continues to advance rapidly and modern mixes with five components – cement, additions, aggregates, (chemical) admixtures and water – often have characteristics which differ significantly from the older three component mixes – cement, aggregates and water. Recent trends have favoured higher strength classes and lower water/cement ratios, resulting in greater dependence on admixtures to compensate for reduced workability and to meet the (often competing) demands for workability in the fresh state and setting time. The application of testing methods which reflect the true rheological properties of the concrete has not developed at the same rate as the mixes themselves and it is still not uncommon for the slump or flow table test to be used as the only acceptance test for fresh concrete.A joint review of problems in bored piles (drilled shafts) and diaphragm walls cast using tremie methods by both the European Federation of Foundation Contractors (EFFC) and the Deep Foundations Institute in the United States (DFI) identified a common issue. The review determined that many of the problems were caused by (or in part due to) the use of inadequate concrete mixes with inadequate workability, or insufficient stability or robustness of the mixes. It further identified the primary causes as inadequate concrete specifications and inadequate testing procedures. The consequences of these problems are often significant and it has been recognised that spending more time and money on getting the concrete right is the most cost effective approach.A joint Concrete Task Group was set up by EFFC and DFI in 2014 to look at this issue and this guide is the output from that Task Group. A research and development project, funded by the Sponsors of this guide, is being carried out by the Technical University of Munich in conjunction with the Missouri University of Science and Technology. This project includes desk studies, laboratory testing, and onsite testing at worksites in Europe and the US. The research work will be completed during 2016.

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

Jan 1, 1995

By BRETTMANN TRACY

Jan 1, 2000

By Allan Sylvester

This paper will discuss the design, construction, and performance of the support of excavation on the San Diego State University LRT Station. The vertical elements of the system include drilled secant piles and drilled soldier piles. We will discuss the geo-technical characteristics, design and construction considerations, loading criteria, construction techniques, schedule constraints, and performance of the pile and support of excavation systems. In consideration of the conference theme, there will be a discussion of the successful accomplishment of meeting the interim milestone dates of the Contract. The project team cooperatively worked to design and install approximately 1,100 drilled secant and soldier piles as well as excavate and install the balance of the support of excavation elements in such a manner as to minimize the disruption to campus students and operations.

Jan 1, 2002

Jan 1, 1990

By Camilo A. Alvarez, Stephen K. Harris, Brian R. Zuckerman, Philip J. Meymand, Danielle M. Steinmetz

"The sleek new air traffic control tower at the San Francisco International Airport stands at 221 feet tall and is set to replace the existing air traffic control tower by 2016. This aluminum-clad, torch-like structure and three-story Integrated Facilities Building at the base are situated between Terminal 1 and Terminal 2 adjacent to the tarmac. Berkel & Company Contractors, Inc. and Simpson Gumpertz & Heger Inc. worked in conjunction with structural engineers from Walter P. Moore Engineers and Consultants, geotechnical engineers from URS Corporation, architects from Fentress Architects, and general contractors from Hensel Phelps Construction Company on the performance-based design of a foundation to support this critical facility, which is located in a high seismic zone and situated on the very soft soil of the San Francisco Bay margin. With the loading demands and performance criteria established and Young Bay Mud thicknesses ranging from 44 to 47 feet thick across the site, the design team employed a total of 214 24-inch diameter Auger Pressure Grouted piles, which were drilled into the underlying Franciscan Formation as deep as 148 feet below existing grade. Pile reinforcement included full-length confined cages.The piles were designed to resist Maximum Considered Earthquake axial demands as high as 1,400 kips in compression and 700 kips in tension. The performance-based pile design included verification of shear capacity under double-plastic-hinge flexural mechanisms, verification of pile ductility via non-linear moment-curvature analyses, and consideration of curvatures due to kinematic as well as inertial loading.The team implemented an extensive pile load test program including a full-scale static compressive load test on a sacrificial test pile and five non-destructive high-strain dynamic load tests, four of which were performed on indicator piles that were later used as part of the foundation system. These piles were monitored with extensive embedded instrumentation throughout their length, including strain gauges and accelerometers."

Jan 1, 2017

By Babak Mamaqani, Pirooz Barar

The Heights project was located at Fashion Valley North, San Diego, CA. The scope of the project was to replace two existing commercial buildings with a large 7-story multi-family residential building. There was an existing 1:1 slope on the north side of the site. A permanent soil nail wall, 1,000 linear ft long, with a maximum height of 100 ft, was needed to replace the 1:1 slope at the north side of the project to accommodate the development. Previously there was a design for the permanent soil nail wall which required up to 115 ft long soil nails with large diameter rebars and 13 in. thick permanent facing. PB&A was engaged by the owner to conduct soil nail design optimization and value engineering to reduce construction costs and improve scheduling. First, the SnailPlus program was used to check the stability under static and seismic conditions and to design soil nail lengths and sizes. Then, soil nail head forces were calculated to design the permanent facing using FHWA recommended procedure. Another challenge of the project was to evaluate the interaction between a future San Diego Gas and Electric (SDG&E) tower and the soil nail wall. Finite element analyses were conducted with the PLAXIS program to ensure the deflection of the future tower would be within the acceptable range. The soil nail design optimization helped the owner to save approximately $800,000 in construction cost and improved construction scheduling.

Sep 8, 2021

Jan 1, 1988

By Alexander Ciccone, John H. Gill

Jet grouting is a highly versatile ground modification technique that can offer significant commercial and technical advantages over traditional concrete pit underpinning applications. Despite these advantages, jet grouting remains an underutilized technique in the construction industry due to its perceived complexity, cost, and risk. When performed thoughtfully, underpinning by jet grouting offers significant safety and schedule advantages over traditional underpinning approaches. The New England construction market has seen a recent acceptance in the use of jet grout underpinning on congested project sites across a variety of subsurface conditions. The reduction of the cement batch plant footprint due to equipment advances has allowed the use of this technique in urban sites where its use would be previously infeasible. Furthermore, jet grout underpinning has been utilized for support of historic and sensitive structures with generally lower tolerance to settlement than is typically feasible with conventional pit underpinning. Robust, real-time geotechnical instrumentation monitoring systems have helped reduce the uncertainty and further expand the feasibility of jet grout underpinning applications. When properly designed and constructed by qualified and experienced jet grouting contractors, the flexibility of soilcrete for design and construction may be utilized to overcome the many inherent challenges which complicate underpinning and earth retention systems. INTRODUCTION The construction of buildings and infrastructure in our increasingly dense urban spaces often requires excavations below the elevation of existing structures immediately adjacent to the proposed work. Where a proposed excavation system encroaches into an existing structure’s zone of influence, additional measures, such as the construction of an underpinning or excavation support system, are required to safely excavate and minimize the impacts on the adjacent structures. Jet grouting is one method of underpinning that offers significant commercial and technical advantages over many other techniques. Though it was first used to the United States in the 1980s and has grown in popularity elsewhere, jet grout underpinning remains underutilized domestically due to its perceived cost and risk premium. Jet grouting has significant technical advantages over other underpinning methods due to its applicability in a wide range of soil types and its flexibility of design and installation. The jet grouting process is capable of limiting the movement of foundations during construction and excavation to lower thresholds than most traditional underpinning methods (Droof, Furth, & Scarborough, 1995). Its use for underpinning historic and sensitive structures with lower settlement criteria provides additional evidence to its technical utility. Through thoughtful design, adequate planning, and experienced installation, jet grouting can be an appropriate underpinning solution that can provide significant cost and schedule savings.

Jan 1, 2019

By Lois G. Schwarz

I did a project (Sungai Piah) as a consultant to your firm in Malaysia, where we were faced with a similar situation as sketched out in your question. The following is what we did for the grouting of the primary holes, which were both located upstream of the plug as well as downstream: We used a hydrophobic MDI based semi-rigid polyurethane prepolymer in the first phase of the grouting operation when grouting under water flow conditions. Then in the second phase and also for the contact grouting we used a two component water compatible polyurethane elastomer. And then for deeper formation grouting, when all the water flow had been stemmed in the vicinity of the plug, we used a regular (balanced stable) cement based grout. So it may not exactly answer your question, but we first used hydrophobic grout because it is very efficient to grout a formation through which water flows. We didn't stop all the leaks day-lighting downstream of the plug or all water running through the formation near the plug, but the flow of water through the rock formation adjacent to the plug was reduced by 99.9%, after completing the urethane grouting. This facilitated the placement of cement based suspension grouts without wash-out.

Feb 10, 2003

Jan 1, 1997

Jan 1, 1993

Jan 1, 2005

By Han Jie

The results of full scale plate load tests on stone columns on soft clay in coastal areas are presented in this paper. Four load tests were made, two of which were performed on the ground treated with stone columns, one on an isolated stone column and the last one on the untreated ground. For a given stress range, the settlement of the rigid plate, the stress concentration factor, and the excess pore water pressure were measured. It is found that the distribution of vertical stress beneath the rigid plate supported by the composite ground of stone columns is very different in shape from the one by the untreated ground, that the stress concentration factor has a relation with the stress level and time, that the stone columns increase the bearing capacity up to by 2 times, and that the ground stabilized by stone columns is of great advantage to keep the foundation stable.

Jan 1, 1991

By Athul Prabhakaran, Ramin Motamed, Ahmed Elgamal, Milad Jahed Orang, Reza Boushehri

Documented case histories from past earthquakes have exhibited the devastating effects of the liquefaction phenomenon on the performance of buildings that are often presented in the form of excessive settlement of shallow foundations. Example earthquakes include the 1964 Niigata earthquake in Japan, and more recently the 2010-2011 Canterbury Earthquake Sequence in New Zealand, and the 2011 Tohoku earthquake in Japan. All of the listed events comprised several examples of severe liquefaction-related damage to the buildings founded on shallow foundations. Although the liquefaction-induced building settlements have been experimentally studied extensively since 1964 using shake table tests and dynamic centrifuge experiments, studies focusing on cost-effective mitigation strategies are still limited. In this study, the performance of helical piles as a cost-effective countermeasure to minimize the damaging effects of liquefaction-induced ground settlements on buildings founded on shallow foundations is studied. Two large-scale shake table experiments were conducted at the University of California, San Diego (UCSD) to investigate the effectiveness of helical piles in liquefiable grounds. Results from these two experiments highlight a highly improved performance of a shallow foundation supported on helical piles. These largescale shaking table experiments demonstrate the efficiency of using helical piles as a cost-effective countermeasure to reduce the liquefaction-induced building settlement.

By Stefan Swartling, Rudy Lyon, Donald A. Bruce

"Since their first production application in Sweden in 1995, water-powered, down-thehole hammers (WDTH) have been used throughout the world in many different drilling applications, total lines, over 25 million lineal meters of drill hole. This paper reviews the history and principles of down-the-hole drilling (DTH) in general with both air and water, before focusing on the details of WDTH hammers. A summary of the numerous and considerable advantages of WDTH drilling is provided, with particular emphasis on their superior productivity, smaller deviation, applicability in sensitive/urban conditions, environmental protection and much reduced energy requirements.HISTORICAL PERSPECTIVE ON PRODUCTION DRILLING METHODSAir-flushed drilling with top hammers began in the mining industry in Sweden in 1873, while down-the-hole (DTH) drills, again with air flush (and activation) became operational in 1950. During that same time interval, Simon Ingersoll had patented the first steam-powered, top hammer rock drill to provide higher productivity in blast hole drilling. It is well known that water, as an activating, flushing and cooling medium, has many significant advantages over the use of air. However, it was not until 1973 that top hammer systems (either air or hydraulically activated) for larger rigs were adapted to the use of water flush, typically via “under the head” swivels.The concept of a water-powered, down-the-hammer (WDTH) had been explored prior to G. Drill acquiring the original patent from Atlas Copco in 1988. LKAB, a huge underground mining company owned by the Swedish Government and providing about 90% of the European Union’s iron ore, purchased G. Drill in 1991 and encouraged the commercial development of the WDTH. The first full-scale WDTH production works were carried out for LKAB in 1995, since when over 25 million lineal meters of drilling have been recorded in both underground and surface applications.In 2001, G-Drill was renamed Wassara, which today still holds the worldwide patents for WDTH technology. Regarding North American usage, the first significant application was by Advanced Construction Techniques (ACT) Ltd. during the test grouting program conducted for the U.S. Army Corps of Engineers at McCook Reservoir, Chicago, in 2002. Since then, WDTH has become the tool of choice for specialty drilling and grouting contractors on dams and other major structures throughout the U.S."

Jan 1, 2015

By Peter J. Nicholson

The methods of reinforcement to be discussed in this paper are all insitu methods, ones that can be used on the soil structure as it exists in the ground, and do not rely on excavation and replacement of the soil. Current practice in the United States, as well as new ideas and methods, will be discussed as they relate to slope stability, retaining walls, and to other uses such as control of mine or cavity related subsidence and to liquefaction control under existing structures. The method is based on the concept of "nailing" or reinforcing the soil in place, and thereby causing a mass of soil to act as a coherent unit. When performed properly, a true gravity structure can be constructed, one that will remain intact under both horizontal and vertical loadings and that will also resist vibrational and seismic loadings.

Jan 1, 1991