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By Wu Jie Mei, Li Yao Liang, Franz-Werner Gerressen, Arthur Bi

Diaphragm walls (D-walls) are known as underground structural elements commonly used for retention systems and permanent foundation elements. In addition, they are also quite often used as deep groundwater barriers, called Cut-Off-Walls (COW). Shanghai ranks third among the most densely populated metropolises in the world. In 1990, only eight million people lived there. Today, Shanghai has about25 million inhabitants. The increasing demand to accommodate the infrastructure of growing megacities like Shanghai pushes the required depth for subway, sewage and foundation projects to the limit. Future projects will demand excavation depths of more than 100 m (328 ft) on a regular basis. Already carried out reference projects will be described and a general outlook for upcoming projects will be given. The paper also explains the installation process in general focusing on the use of trench cutter technology. INTRODUCTION D- walls are known as underground structural elements, commonly used as retention systems for excavation pits and shafts as well as permanent foundation walls or elements. It is anticipated that, with the increasing trend of utilizing more and more underground space to accommodate environmental considerations and urban/suburban development, there will be an increasing requirement for diaphragm wall usage in even more difficult conditions and with increasing depth. The trench cutter is the most important tool for performing this work. The hydraulic grab, a well-known and valuable excavation tool for d-walls reaches its limits in terms of depth and when cutting rock. Therefore the trench cutter technology will be in the focus of this paper. The trench cutter itself is a reverse circulation excavation tool. It consists of a heavy steel frame with two drive gears attached to its bottom end, which rotates in opposite direction around the horizontal axis. Cutter wheels are mounted onto the drive gears. As they rotate, the soil beneath the cutter wheels is continuously broken up, removed, mixed with the bentonite slurry in the trench and moved towards the opening of the suction box of the pump? A centrifugal pump located right above the cutter wheels conveys the slurry via a hose system up to a desanding plant. There the slurry loaded with soil and rock particles is cleaned and returned into the trench.

Jan 1, 2018

By J. Matos e Silva

"Abstract Although one can think that it is very low the probability of a seism occurrence during the execution of an excavation in an urban lot protected by a diaphragm wall curtain, reality shows that whenever a seism occurs in an urban area several diaphragm walls will be affected by it. So it is advisable to consider the seismic action when designing a diaphragm wall curtain. The paper refers the main information about the seismic design of diaphragm walls according to the Eurocodes 7 and 8 and to the Portuguese Norms related to them (respectively NP EN 1997-1 2010 and NP EN 1998-5 2010), as the Eurocodes consider the possibility of each European country to adopt their own seismic parameters as the seismic risk is different in each country. Thus the so-called National Document of Application (in our case the Portuguese Norms) prescribes the seismic local parameters.1 - EUROCODES AND PORTUGUESE NORMS PRESCRIPTIONSAccording to Eurocode 8 - Part 5 and to the related Portuguese Norm NP EN 1998-5 2010, seismic actions on soils should be quantified adopting the Mononobe-Okabe method that gives goodapproaches when compared with reality.From paragraph 7.3.2.2 of the referred Norm, the horizontal seismic coefficient kh will be:"

Jan 1, 2014

By Walter Ensinger

Working safely means working cost-effectively. Every "dangerous occurrence" and - even more so - every industrial accident causes disruptions in the planned course of construction. Besides moral and legal obligations, economic aspects are therefore also factors motivating increased efforts towards optimal prevention: improvements in work safety and protection of health are wise investments! Ever since its earliest days, the European Federation of Foundation Contractors (EFFC) has made this subject one of its key objectives and therefore set up a Safety + Environmental Working Group, in which experts from the member organisations exchange national experience and develop proposals for "best practices". The paper presents current developments and results from the work of the S+E WG with particular reference to the project "Ideas for Safety Improvement".

Jan 1, 2006

Port Gaspé is located on the back side of Gaspé bay and is protected by a natural sand barrier with a length of 2,5 km, from which it got its name, Gaspé Sandy Beach (1). Since 1904 the Gaspé region had a deep water wharf, initially very different, in fact, from the one existing just before the recent reconstruction (2). This wharf with a length of 228 m and a width of 23 m was build of timber cribs. The outside walls of these cribs had been doubled with a wooden wall, creosote impregnated to provide resistance to decay and to the attack of marine organisms (limnorias) (3). Fifteen years ago the upper part of the wood construction had to be removed, because of progressing rottenness and was replaced by an L-shaped reinforced concrete structure (4).

Jan 1, 1987

By Sanjeev Malhotra

The American Petroleum Institute (API) method of predicting pile capacities in sands is reviewed. Factors that influence pile capacity such as soil parameters, pile parameters, loading effects and installation effects are listed. In addition, the simultaneous occurrence of physical phenomena such as grain crushing, pile shaking, stress-redistribution and plugging add to the uncertainty in the prediction model. To better understand the method of prediction, each parameter and the associated uncertainty is revisited. It is evident that these factors are inter­related and sometimes compensating. This discussion also draws attention to the influence that pile installation procedures can have on pile capacities and highlights the need for field experience with various pile installation procedures for designers. In summary, the strength of the method lies in its simplicity and ease of application, but the possible savings generated by an improved method are too substantial to ignore.

Jan 1, 2000

By Heinz Brandl

Box-shaped pile and diaphragm wall foundations have proved suitable for transferring heavy loads of bridges, power plants, tanks, towers or other buildings in a concentrated form into the ground. The bearing-deformation behaviour and the earthquake resistance of such "box-foundations" are superior to those of conventional pile groups. The reason lies in the reduction of lateral soil displacement and in the composite effect between concrete elements and the enclosed soil. The paper describes results of comprehensive model tests and in situ measurements, theoretical aspects and case histories.

Jan 1, 2002

By A. R. Jambekar

City of Bombay has been developed out of former 7 islands. Landmass of 434 sq.km. of Bombay, started looking inadequate for further growth and expansion of Bombay City. In order to develope twin city of New Bombay, State Government formed fully owned Company "City and Industrial Development Corporation of Maharashtra Limited", (CIDCO) in 1971 and entrusted it with planning and development including social and physical infrastructure of New Bombay.Hence, Trans - Thane Creek area is being planned and developed, to serve as counter-magnet to Bombay. Area of 343 sq.km located on the main land, is fast developing into a satellite community, for India's overcrowded financial capital. Thane Creek, running in almost North-South direction, separates Bombay City from main land and posed a significant barrier, to further expansion of city's sprawling suburbs, until, it was bridged for the first time in 1972. On the basis of traffic study, CIDCO decided to construct an additional road link across Thane creek to cope up with future projected traffic. This bridge will connect Airoli in New Bombay and Eastern Express highway near Mulund. Bridging the vast, exposed tidal Thane Creek, have always posed challenging conditions, during constructions of these bridges. In this paper, case history of deep open foundations provided for Airoli Bridge is presented.

Jan 1, 1996

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

? Hollow Stem Auger ? Drill Bits ? Leads/Torque Arm ? Hydraulic Gearbox ? Hydraulic Power Unit ? Grout Pump ? Crawler Crane

Jan 1, 2000

By Darrell L. Beddard

The Loma Prieta earthquake occurred on October 17, 1989 at 5:04 PM, Pacific Daylight Time. It measured 7.1 in magnitude and was felt from Los Angeles north to the Oregon state line and east to western Nevada. The epicenter of the earthquake was located along the San Andreas Fault, in the Southern Santa Cruz Mountains just north of the City of Watsonville, California. It was the largest earthquake to occur in the San Francisco Bay area since the 1906 earthquake. A total of 87 aftershocks of Magnitude 3.0 or larger were recorded within 21 days after the seismic event. As a result of this earthquake thirteen State-owned and five locally-owned bridges were closed to traffic. Three of the most publicized State-owned structures closed to traffic were Struve Slough Bridge, San Francisco-Oakland Bay Bridge and Cypress Street Viaduct. Struve Slough Bridge was twin slab bridges that collapsed and were rebuilt and open to traffic three months after the earthquake. San Francisco-Oakland Bay Bridge experienced collapse of upper and lower spans at Pier 9 and was reopened to traffic one month after the earthquake. The Cypress Street Viaduct experienced collapse of 48 bents that resulted in the upper roadway falling onto the lower roadway.

Jan 1, 1995

By Dennis J. Riley

A. This outline addresses what a sub-contractor, or a subsub-contractor should do to get paid in the event the general contractor or building owner files for bankruptcy. B. Negotiating payment terms. Progress payments vs. "pay when paid". How a sub or subsub can avoid financing the contract. C. Court interpretation of "pay when paid" clauses allow postponement not excusal of payment. See, e.g., Seal Tite Corporation v. Ehret. Inc., 589 F. Supp. 701 (D.N.J. 1984) (where the court held that the general contractor could not delay payment indefinitely to the subcontractor in the event of non-payment from the owner); United Plate Glass Co. v. Metal Industries. Inc., 525 A.2d 468 (Commw. Ct. Pa. 1987) (where the court held that payment from owner was not a condition precedent to paying subcontractor but instead a timing mechanism indicating when payment should be made); But see. Straham v. Landis Construction Co., 499 So. 2d 417 (La. App. 4 Cir. 1986) (where the court strictly interpreted the "pay when paid" clause).

Jan 1, 1991

By J. Nakayama

Construction of foundation piles or diaphragm walls through rocky or boulder containing formations has been long-standing difficulty. It has been widely understood that the down-the-hole hammer is the most capable mechanical means but is restricted in drilling diameter by the unavailability of drillhead sufficiently large diameter and the difficulty of disposal of cuttings. A great number of submersible motordrills have been used for the construction of cast-in-place piles and diaphragm walls and the reverse circulation system employed has demonstrated its advantage of the prompt removal of cuttings. The development of multi-head down-the-hole hammer drill combined with reverse circulation system presents a powerful engineering choice for those "hard-to-drill" ground formations. This paper will introduce the features of the system and some actual operation results in the foundation engineering through those hard rocky ground formation in some countries.

Jan 1, 1989

By W. Robert Thompson

Hurricane Katrina caused significant damage to transportation structures on the Gulf coast in August, 2005, including the destruction of the US 90 Bridge over Biloxi Bay, Mississippi. Part of the successful design/build proposal for the replacement bridge included a comprehensive test pile program of indicator piles and load test piles in the geotechnical investigation program. A total of 22 indicator piles were installed on the project using the pile driving analyzer to monitor the pile behavior. Five load tests were performed: two axial Statnamic, two lateral Statnamic, and one static axial. The results of the test pile program established driving criteria for production piles that included end-of-drive blow counts and pile tip elevations with an appropriate allowance for setup. The program also confirmed that the planned installation equipment and techniques of GC Constructors, a joint venture of Massman Construction Co., Kiewit Southern Co., and Traylor Bros., Inc., would install the piles to the design tip elevations before production piles began. An extensive program of restrike measurements at a range of times after initial driving of the indicator piles provided a systematic documentation of pile setup in the soil profiles on the site. These resistance values were used to develop a dimensionless setup factor ?S? as the ratio of the restrike resistance to the end of drive resistance. This factor varied from 1.5 for piles penetrating clays and tipped in sand to 3.0 for piles bearing completely in clay and helped establish an end-of drive blow count that included an allowance for setup. The CAPWAP analyses of restrike data with setup and the load test data were used to confirm the design unit side shear and end bearing values developed from the borings and static capacity calculations and to select the design pile lengths.

Jan 1, 2009

By Shamsher Prakash

Equivalent spring constants for analysis of footings is a function of Young's modulus of pile material (Ep), shear modulus of soil (Gs), and geometry of the footing and/or piles. Shear modulus is strongly strain dependent in soils. Therefore, the spring constants are strain dependent, which is acceptable to the Geotechnical engineers. However, structural engineers prefer to use spring constants as a function of displacement, rather than strain. In order to develop these relationships, appropriate relationships between strain and displacement are needed. Also, modulus degradation with strain needs be built into these relationships. Description of spring constants kx , ky, and kz in x, y, and z direction and k?, k?, k?, about x, y, and z directions are relatively simple. However, description of kxø and ky?, the cross-coupling spring constants depend on 2 - components of displacement and rotation. Thus, there are 8 spring constants and likewise there are 8 damping constants. Approximate strain-displacement relationships on which displacement dependant k's and c's are based are presented with appropriate equations, and a numerical example is included illustrating k's and c's as functions of displacement.

Jan 1, 2002

By Jeffrey A. Schaefer

The Olmsted Locks and Dam project is located on the Ohio River approximately 16.5 miles upstream of its confluence with the Mississippi River. It consists of twin 1200 ft. locks with floating and fixed approach walls, five 110 ft. wide tainter gate bays, a 1400 ft. wide navigable pass boat operated wicket gate section, and a 400-ft. section of fixed weir (Fig. 1). The project will have a total cost over 1.0 billion dollars, and as such is one of the largest civil works project underway in the Corps of Engineers.

Jan 1, 2001

By Kenneth Gavin

The accurate prediction of the shaft capacity of drives piles in sand continues to present problems for foundation designers. Research in this field has been carried out for many years and has yielded a wide range of design approaches -some of which have been shown by recent experimental work to be based on questionable assumptions. This Paper reviews some of the current popular design methods for piles in sand in the context of recent information obtained from high quality field tests conducted by institutions such as Imperial College London. A database of driven piles in cohesionless soils has been compiled from well documented (and reliable) case histories that have been reported in the literature. The measured shaft capacities of the piles in this database are compared with predictions made by the various methods and an assessment is made of the predictive performance and reliability of each method

Jan 1, 1996

By Matthew Janes

Statnamic load testing is becoming widely accepted as a method to quickly and economically determine the load-deflection behaviour and ultimate static resistance of high capacity deep foundations. Strain instrumented large diameter bored shafts were tested at four locations for the federal and state Departments of Transportation in the United States. Tests were conducted vertically (to 30 MN) and laterally on the shafts and, in some cases, testing was completed over water. Instrumented shaft test results provided shaft load distribution with depth and shaft shear transfer stress throughout the soil stratum. Shaft end bearing and ultimate end bearing stress values were provided. On two projects, Osterberg load cells provided comparative static data for skin friction and end bearing. Correlations between Statnamic derived static load-displacement results and Osterberg load-deflection results are very good. Statnamic lateral load test results were correlated with static lateral results in addition to providing useful dynamic response and damping data.

Jan 1, 1996

By A. M. Hanna

This paper presents the experimental investigation on the ultimate skin friction of batter piles. The model piles were pushed in medium dense sand deposits at different inclinations up to 30 with respect to the vertical and tested under axial compression loads. The decrease in the total skin resistance with increasing pile inclination can be explained in terms of the reduction of the ave­rage mobilized angle of friction between the pile shaft and sand. The analysis, which takes into account asymmetrical earth pressure distributions around the pile shaft, showed good agreement with experimental results.

Jan 1, 2010

By George K. Burke

Jet grouting was first introduced into North America in the late 1970's, soon after the conception of the system in Japan. However, it was not until the mid-1980's that the technique began to gain acceptance through the renewed interest and efforts of specialist U.S. geotechnical contractors. Since this time, innovations by both American users and other users worldwide have further advanced the technology, with a corresponding increase in the range of practical applications. This paper discusses the evolution of jet grouting in North America, from simple single-fluid methods to more complex triple-fluid methods, to the energy-intensive double-fluid and SuperJet methods. Case histories, illustrating a variety of jet grouting methods and applications, are cited to support the newest United States applications.

Jan 1, 2002

By Jay A. Berger

Nondestructive testing of deep foundations for integrity problems made great strides in the late 1980's. Inexpensive portable computers have allowed the immediate and rapid processing of field measured acceleration records which can provide insight into the relative structural integrity of a previously installed foundation member. Although the gathering, processing and displaying of the data is now straightforward, interpretation remains at times rather challenging. This paper provides a brief introduction into the theoretical basis for data interpretation and the hardware necessary for data acquisition. Five case studies are discussed which demonstrate the varied applications of low strain integrity testing of deep foundations and the efficiency at which they are completed. BACKGROUND One dimensional wave mechanics, when applied to a linear elastic pile with a length that is an order of magnitude greater than its width, provides a straightforward basis for the interpretation of motion measurements made at a pile top. When impacted, a stress wave travels through the pile at a wave speed, c, which is a function of the elastic modulus, E, and mass density p (i.e., E=pc2). The applied load F, and particle velocity v, at a point are related by the equation F=Zv. For a cross-sectional area A, the proportionality constant Z is equal to EA/c. Because Z is a measure of the pile's resistance to change in velocity it is called the pile impedance.

Jan 1, 1990