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By Richard Crockford

The World Trade Center (WTC) is located on the west side of Manhattan in New York City, approximately 0.5 miles north of Wall Street, and is owned and operated by the Port Authority of New York and New Jersey (PA). As part of the WTC site redevelopment the New York City Transit Authority?s No. 1 subway line which runs through the site below grade, was underpinned so that the soil beneath it could be removed along with the rest of the new east basement excavation. Consequently a scheme comprising micropile installation through and around the existing subway box was designed. The subway had to remain in use throughout save for planned weekend outages to allow a portion of the underpinning to be fitted through or on to the existing structure. At times this involved accessing and drilling from within the subway tunnel under short General Order (GO) Subway shutdown periods. At either end of the subway passage through the WTC site jet grout underpinning was designed to provide support and to complete the excavation and construction of the east basement wall in the areas beneath the subway where it was impossible to install a slurry wall. The jet grout blocks thus formed had to be largely installed around the clock during 53 hour long GO weekend outages and had to overcome severe logistical constraints in and over the tunnel. The jet grout blocks had to provide strengths of at least 500 psi at 3 days and 700 psi at 28 days. The jet grouted soil mass also had to have a level of permeability less than 0.03 feet/day (1 x 10-7 m/s). After an extensive trial program and then production testing it was concluded that the glacial till above the rock proved to be a particularly difficult soil strata to collect test data from and hence the level of observational monitoring was increased to progress the excavation works. Throughout the installation of micropiles and jet grout columns extensive monitoring was in place and prompted a variety of working method changes. The work described in this paper was performed by the Nicholson Construction Company/EE Cruz Joint Venture.

Jan 1, 2008

By Evangelia Ieronymaki

Civil engineering education relies on traditional methods of teaching, comprising mostly of deductive instruction by presenting the theory, followed by applications. This paper presents an alternative way for teaching foundation design to senior students, introducing a more inductive approach. The students are presented with a project/game adapted to a real-world problem at the beginning of the course. They are asked to identify the correct steps and methods throughout the lectures, for reaching an appropriate solution that they document and present at the end of the course. To make the project more enjoyable, the project has the format of a game where the students compete with each other on completing the task faster and more efficiently. The goal of this teaching approach is to enhance the ability of the students for problem solving and the engineering way of thinking, while playing a game. In the end, the students were requested to respond to a survey regarding the efficiency of this project/game on their learning. The results showed that students prefer more inductive methods for a design course, feeling that this project made them think more like engineers, while the ‘game’ twist of it made the whole course more fun. INTRODUCTION Most civil engineering courses are taught in 2019 the same way they used to be taught 40 years ago in the 80s. Classic methods are mostly deductive, where the instructor presents the theory first and then applications of that theory follow. Little or no attention is given initially to why the theory was developed or what are the problems it solves. The applications of the theory, and thus the purpose it serves, come only in the end and after methodologies have been presented, leading the students to show low interest in the material. As Albanese and Mitchell (1993) have reported, people are mostly motivated to learn things when they clearly see the need to know them. This explains the students’ little motivation that, if any, comes mainly from the fact that the material may be useful either in other courses or in their future careers. On the other hand, there are alternative inductive methods of teaching, where the role of the students is more active. A lot of researchers have highlighted the benefits of inductive methods in teaching engineering courses. Based on Prince and Fedler (2006), inductive methods include; a) inquiry-learning, b) discovery learning, c) problem and project-based learning (PBL), d) case-based teaching, and e) just-in-time learning. Inquiry-learning is maybe the most traditional method of inductive teaching/learning methods, where the instructor asks questions or poses problems and the students need to apply the theory they have learnt in order to find the solution (Bateman 1990; Prince 2004; Lee 2012). Similar to inquire-learning is the discovery learning, where students have to find the solution to a problem or answer to a question, while the instructor simply provides feedback to the students without guiding their efforts (Leonard 1988; Westbrook and Rogers 1994).

Jan 1, 2019

By Takashi Saito

Since early 1970?s skirt suction foundations (skirted foundation / bucket foundation) have been used as support for large fixed substructures or anchors for floating structures in offshore hydrocarbon development projects. In recent years skirt suction foundations are recognized as one of the solutions in foundations applicable to bridge substructures installed in waters, because skirt foundations have a wide variety of functions such as control of settlement during service life, less impact to environments during operation at installation site. This paper introduces general features of skirt suction foundations, and then discusses design practice of them for the application to bridge substructures, with reference to experiments in both laboratory and field.

Jan 1, 2013

By Harpal Parmar

This paper evaluates dynamic methods of pile capacity prediction by comparing their results to static load test results. Dynamic and static pile load test data were assembled from four southeastern states of the U.S. End-of-drive and restrike capacities were evaluated using the Pile Driving Analyzer (PDA) and by wave equation (WEAP) analyses. These were compared to static (Davisson criterion) loads. The best comparison was obtained for restrike PDA results; restrike wave equation analyses values also compared well. The end-of-drive results for both methods-showed relatively poor comparisons. The PDA was recognized as an important tool to measure energy transferred to the pile; this transferred energy was recognized as an uncertainty when conducting wave equation analyses. A statistical analysis showed restrike capacity results to be associated with higher precision and accuracy as compared to end-of-drive methods. The authors believe that restrike dynamic testing is essential to establish long term static soil strength and that it will lead to accurate and cost-effective design of piles.

Jan 1, 1996

By M. Pernot

A 12 m-deep excavation has to be perfomed in the Shanghai soft clay to install an underground electric substation. This article was originally intended to study the behaviour of the wall, the excavation bottom and the surrounding ground during the excavation. Since the works are behind schedule, and the data referring to the excavations are not, therefore, available, the article is limited to a presentation of the analysis methods that we envisaged for the study of the behaviour of the excavation.

Jan 1, 2010

By Cassandra A. Wetzel

Rock socketed mini-piles are a desirable foundation alternative when design capacity is more than 40 tons and there is limited access. In this case history mini-piles were designed to support between 75 and 200 kips at 12 locations adjacent to a perimeter wall, a party wall and at cast iron column piers. Limited geotechnical information, low overhead clearance, and active building population tested the creativity of the team to get the piles installed. The key geotechnical concern during installation of the mini-piles was the presence of a glacial till layer above the bedrock surface that restricted the seating of the casing into bedrock with a track mounted drill rig. Soil loss during the advancement of the rock socket using an air hammer was excessive and increased the risk of subsidence. Over a three week period the engineer worked with the contractor to modify the design, means, methods, and materials to install piles with adequate load capacity. This paper will present the changes in design and construction methods that were required.

By Jesse A. Pfeiffer

CPAR, the Construction Productivity Advancement Research Program, is a new initiative of the Corps of Engineers to enhance U.S. construction industry productivity through the development and application of joint-funded research. CPAR seeks to balance the requirements of both the private sector and the Corps of Engineers construction program, to identify research needs that are common to both parties in a partnership for conducting research, and to achieve practical real-world products which will enhance productivity in the construction industry. Increasing costs of doing business has had a major negative impact on much of the nation's industrial base, and research and development (R&D) is among the areas hardest hit. The Congressional Budget Office estimates that since 1984 inflation adjusted R&D outlays in private U.S. firms have risen at an average annual rate of three percent, or about half the rate of gain of the preceding decade. And, despite a significant increase in foreign competition, the portion of gross national product (GNP) devoted to R&D is lower today than 20 years ago. For the case of the U.S. construction industry, the numbers are even more dramatic.

Jan 1, 1989

By Donald R. McMahon

This paper presents a unique case history that documents the use of a braced secant pile wall to underpin a heavily loaded footing inside of a manufacturing plant. Construction of a pit for a new manufacturing process directly next to the footing necessitated the underpinning. The footing supports an overhead crane that needed to remain operational throughout construction of the pit and therefore, settlement of the footing could not be tolerated. The base of the footing was about 7.7 feet above the base of the 17-foot deep excavation. The footing bears on a silty clay deposit that grades from a stiff consistency beneath the footing to a soft/medium consistency near the base of the pit excavation. This paper describes the design and construction of the secant pile wall and bracing to control wall deformations, ground movements and settlement of the footing. The footing was monitored for settlement throughout construction of the pit and no measurable movement was observed.

Jan 1, 2006

By Andrew Pontecorvo, Steven Lowe, David Sposito

Buildings with large height-to-width ratios require foundations with significant uplift resistance. This paper presents a case study of the permanent rock tiedowns installed for One Manhattan West, a sixty-seven-story office building in midtown Manhattan. Site access and schedule dictated the size of the equipment for installing the tiedowns would be limited to drilling a 16 inch (406 mm) diameter hole. A three bar configuration of 3 inch (76 mm) diameter high strength threaded bars was chosen to develop an allowable capacity of 923 tons (4060 kN) per tiedown. Although the quality of the rock at the site was generally high, a challenging geologic condition emerged during the installation of one of the tiedowns requiring a creative installation procedure. Although the three bar configuration performed relatively well there are challenges with loading and testing this bar arrangement. Unlike single bar tiedowns that are typically tested with a high success rate, testing of a multiple bar system can result in some unsatisfactory results. This may be attributed to the installation challenges, difficulty loading each bar uniformly and/or the method of monitoring the test. Understanding the complexities is necessary to improve the testing results and achieve similar reliabilities of single bar systems.

By Peter McDonald

In 1994 the world's largest underwater tunnel was constructed to link Canada and the U.S.A. This new tunnel was large enough to accommodate double-decker railway cars. The construction of an unplanned Retrieval Shaft was required to allow removal and servicing of the Cutterhead of the Tunnel Boring Machine before it passed under the St. Clair River. This paper, which is a revision of that published in Canadian Tunnelling, has been modified here to emphasize construction considerations and describes the evolution of the design and construction of this "Rescue Shaft" under extreme schedule pressure, and changed ground conditions..

Jan 1, 1997

By K. C. Foye

Use of load and resistance factor design (LRFD) of foundations is growing, from offshore applications to bridge applications and beyond. The development of load and resistance factors for design has traditionally relied on calibration to traditional factors of safety. This technique, however, offers little insight into the challenges of pile design. This paper discusses an approach to LRFD factor development that seeks to isolate the various sources of design uncertainty. Using this approach, reliability analysis is used to develop resistance factors for the design of driven pipe piles in sand. These findings shed light on many aspects of the ongoing discussion of how LRFD can be successfully applied to pile design.

Jan 1, 2008

By Larry Rayburn

Design of cost effective engineered solutions to complex problems requires the team efforts of the owner, the designer and the specialty construction contractor. The basic ingredients of success required to remain competitive and still produce a quality product are creative design based on experience and sound engineering principles, plus practical aspects of constructibility. The three case histories describe creative design/construct approaches that benefited all parties. 1. Introduction The increasing demand placed on specialty contractors to provide cost effective buildable solutions to complex construction problems compels us in the industry to be highly innovative. The practice of geotechnical engineering is considered more of an "art" than perhaps the other disciplines within civil engineering largely because of the basic nature and variability of soil and rock. The geotechnical design engineer must have the knowledge of the components of his design and know the limitations of his equipment and labor force. Thus, for the design/build specialty contractor the potential for creation of unusual solutions to difficult problems is quite high.

Jan 1, 1991

By George Machan

Bitumen coatings have been successfully used to significantly reduce downdrag on piles. Thicker coatings of "soft" bitumens can accommodate downdrag so well that very little downdrag load is transferred to the pile. Many of the case histories describe better than 80 percent downdrag load reduction. Bitumen coatings have been used on several projects in Oregon. On the Mocks Bottom Bridge project (see Reference 1), experimentation and instrumentation confirmed the viability of bitumen coatings and provided insights for design and construction. Subsequent bridge projects have used this information and have raised issues to be resolved.

Jan 1, 1989

By Khamis Y. Haramy

Quality assurance and quality control of drilled shafts has become a concern due to difficulties in accurately locating construction anomalies and determining load bearing capacity of defected drilled shafts. Various non-destructive evaluation techniques have been developed to estimate the integrity of the concrete in drilled shafts. While these techniques have been widely accepted, variables and unknowns can affect the measurement results. Results are typically difficult to interpret, leading to unnecessary construction delays and possible litigation over shaft integrity. In addition, influences of surrounding ground materials, stress states under different load conditions, and crack and residual stress development during concrete curing further complicate determination of shaft performance. This paper focuses on the evaluation of load bearing capacity of defected drilled shafts under various conditions by numerical analysis and modeling.

Jan 1, 2007

By Anthony H. Tawil

Modern, high-speed machines used in the manufacture of paper require foundations with stringent settlement constraints. To fulfill this requirement, caisson piles, extending into bedrock, were selected to support a paper machine in Baie Comeau for the Quebec North Shore Paper Company (QNSPCo.). This was the fourth machine in an existing paper mill, and its construction was part of an expansion program which included the building of associated structures such as a wood room and chip storage building, and other facilities, Figure 1. The paper mill in Baie Comeau, Quebec, is located in an area which has extensive deposits of sensitive marine clay which are transformed into a viscous liquid when disturbed by external forces such as the driving of piles. Loss of ground and soil disturbance as affected by piling activity assumed considerable importance in the design and construction of the caissons particularly in view of the proximity of existing plant facilities, including another paper machine.

Jan 1, 1987

There are many ways to classify structural slurry wall elements, but the DFI committee chooses to limit these descriptions to three functional requirements, namely: design function, plan configuration and type of panel reinforcement. (See Figure 1 in Part IV for panel classification). Slurry walls can function as: 1. Curvilinear or linear elements for temporary and/or permanent structures to resist lateral forces transferred from the ground, water, earthquakes and various surcharge loads. 2. Load bearing elements in various plan shapes to resist vertical forces. 3. Combination Elements to resist combined forces under conditions 1 and/or 2. For example, elliptical shafts with various openings for tunnels and conduits have been commonly used for deep excavations.

Jan 1, 2005

By L. C. Reese

? Good construction and inspection presumed. ? Capacity-computation factors are independent of construction method. ? To account for variable or uncertain site conditions, anticipated construction problems, and/or minimal inspection, increase factor of safety. ? Conduct load tests and/or develop easily implemented design alternates (e.g., straight shaft in case bell can't be formed) to reduce factor of safety.

Jan 1, 1988

By Hiren J. Shah

The urban environment and geology create unique challenges for design and construction of deep foundations. The effect of these is prominently experienced in New York City. Three such project case histories are presented in this paper. The first project is a multi-use development. Relatively unusual glacial geology was observed at the site during the subsurface investigation phase. This played an important role in the selection of deep foundations as well as during construction. The design and construction aspects of the pile foundations, settlement estimates, a pile drive test program during design, piling equipment and production pile installation are discussed herein. A relatively smaller project is the second case history. A combination of drilled and driven deep foundations was employed in one area of the project due to its unique conditions. In another area of the project, an addition to a structure required the use of supplemental foundations to resist new additional loading. Tight space and load sharing with the existing foundations were important considerations in the design and construction. Finite element modeling of the existing and completed structure was performed which was an interesting aspect of the project. The third project case history involves a very large multi-billion dollar project in which various different types of deep foundation elements were used. The aspects requiring the use of such a variety of types and sizes of deep foundation elements included: geologic conditions, re-use of existing foundations, protection of adjacent infrastructure, construction staging, restricted space, loads, deep excavations, cost and schedule.

Jan 1, 2011

By Alexander B. Reeb, Richard J. Varuso, George M. Filz, Jehu B. Johnson

"T-walls, which are concrete floodwalls in an inverted “T” shape, are an integral component of the Greater New Orleans Hurricane and Storm Damage Risk Reduction System (HSDRRS). In order to resist large lateral flood loads, T-walls are typically supported on long batter piles that extend through the weak and compressible clays and peats commonly encountered in southern Louisiana. Since the piles are battered, settlement of the compressible foundation soils can result in loads acting normal to the piles and induce pile bending moments. Therefore, the design of pile-supported T-walls is a complex soil-structure interaction problem that requires detailed and careful numerical analysis to accurately estimate the stresses and bending moments in the piles. For this paper, numerical analyses were performed for three cross sections that each included a two-pile T wall system that was installed within a 15-ft tall new levee embankment. The cross sections were identical except that the elevation of the T-wall base was varied. This paper discusses the analyses, and it compares the influence of settlements and flood loading on the pile stresses and bending moments. In addition, this paper includes general recommendations for the analysis and design of pile-supported T-walls in practice.INTRODUCTION AND BACKGROUNDThe recently completed Greater New Orleans Hurricane and Storm Damage Risk Reduction System (HSDRRS) includes 350 miles of levees and floodwalls and is designed to defend against a 100-year storm surge event. The floodwalls predominantly consist of I-walls and T-walls. I-walls are comprised of a sheet pile wall curtain capped with a monolithic concrete wall above grade. T-walls are similar to I-walls, but they include a wide concrete base at grade, which forms an inverted “T” shape, and they are generally supported by long batter piles that provide additional lateral and rotational stability for resisting flood loads.During Hurricane Katrina, several I-walls failed, resulting in large breaches and devastating flooding (Duncan et al. 2008, IPET 2009). T-walls on the other hand performed quite well, including T-walls that were overtopped and eroded on the protected side, yet still did not collapse. As part of the HSDRSS, more conservative designs and height restrictions were required for I-walls (USACE 2011), and a number of I-wall sections were replaced with T-walls. However, the design of pile-supported T-walls is complex and requires careful consideration of both flood loading and settlements."

Jan 1, 2017

By Jack Hayes

Vibrating wire strain gages have proven to be a very reliable and effective tool for the measurement of strains associated with the loading of bored piles (drilled shafts). However, when these strains are used to calculate the load, or stresses in the pile, the results can sometimes be confusing and/or difficult to interpret. This paper describes some of these situations, using examples from actual case histories, and discusses some of the difficulties associated with residual load effects, curing and temperature induced strains, load stress distribution effects, estimated modulus and area.

Jan 1, 2002