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By Zhu Tonghao

A method of calculating anti-slide pile, sheet pile, underground diaphragm and structure with anchors etc. is proposeed in the paper. The effect of the various layers of soil, anchors and bracings etc. on laterally loaded structures may be considered in the model. In the analysis the structure is divided into a series of elements. The transfer matrices of both deformation and internal force are established for each element. According to continuous condition neighbouring element should be connected. Thus the deformation and internal force of each element can be found out in conbination with boundary conditions. The method has a wider adaptability and it can be applicable to a great variety of the analysis of interaction between various structure and soil. If parameters in model are selected properly, the computed results would be in good agreement with the measured data.

Jan 1, 1991

By Madan Kumar Annam, Hari Krishna Y

"Basement construction is one of the challenging geotechnical concerns in the urban environment. Several types of retention systems are practiced to support the earth which is suitable for restricted access, rapid mobilization, fast excavation and cost-effective designs. A thorough understanding of geotechnical engineering as well as the structural mechanics is important for the earth retention systems. This paper discusses a project with various types of foundation solutions including monitoring of deflections during excavation stage of a retention system.A multi storeyed residential building (3B+Stilt+18F) in Chennai having structure foot print area of 1500 m2 has to be constructed on large diameter pile foundations and also to support the proposed basement excavation. Ground water table was encountered at about 6m below the existing ground level (EGL). In order to support heavy structural loads, large diameter bored cast-in-situ piles were chosen and installed. Further, complete retention system was economically designed and built, which includes installation of Contiguous Bored Piles (CBP) in combination of vertical grout columns behind CBP wall to seal the gap between the CB Piles, installation of inclined ground anchors, construction of capping beam, stressing and locking of installed ground anchors. A detailed monitoring program was in place and continuous monitoring of wall deflections is being measured at the time of publishing this paper. This paper describes the design and construction aspects adopted for foundation and retention system including the monitoring results during excavation stage of the project.INTRODUCTIONIn general, stage wise open excavation will be opted for basement construction where plenty of space is available. Due to urbanization and restricted space, open excavation became a difficult task nowadays. To overcome this problem, suitable retention system need to be selected to retain the soil mass. Selection of suitable retention system for multi-level basement excavation is a great challenge in geotechnical industry, especially when the proposed site is located within the minimum set back distance from the existing structures. This in turn calls for the advanced and innovative methods of retention system.Several earth retention systems such as Diaphragm Walls, Secant Pile Walls, CBP system, Soldier Pile Walls, Sheet Piles, Deep Soil Mixing (block walls) etc. with or without inclined ground anchors are being practiced worldwide. Considering the advantages and disadvantages of the available retention systems in practice locally and keeping in view of present site conditions, the developer has chosen CBP system with inclined ground anchors so that all foundation related works of the project will be handled in a single package. The main advantage of such packaged solution will ease the coordination between design consultants and foundation contractor resulting in faster construction of foundation works which in turn reflect savings in time and cost."

Jan 1, 2015

By Mike Muchard

STATNAMIC load testing augmented with embedded instrumentation has been successfully used to obtain structural and geotechnical design information on large diameter spun cast concrete cylinder piles on many large marine construction projects. The paper focuses on one particularly interesting large marine project involving a new bridge to St. George Island, Florida where instrumentation and STATNAMIC load testing was used in conjunction with static load testing on high capacity piles. The information presented includes embedded instrumentation measurements taken during pile fabrication (post-tensioning), during pile driving, during static load testing, and STATNAMIC load testing. As much of this data is the first of its kind on concrete cylinder piles, it is exciting to present the foundation industry with this additional insight as to the behavior of this pile type and the accuracy of the methods used to test them.

Jan 1, 2005

By Madan B. Karkee

The understanding and the development of sound theoretical basis concerning the pile foundations has been phenomenal during the past few decades, considering the thousands of years the piles have evidently been in use. The importance of the quality assurance and the need for verification of load bearing capacity is being further reinforced rather than undermined by these developments. This is evidenced by significant developments made in the pile load test technology in recent decades, making it possible to make judicious selection of a test method, or a package of test methods, suitable for a given situation. The selection depends on the objective of carrying out the test and the reliability desired. Presently, the possible selection ranges from dynamic to static methods. The extent of dynamic effect in a test can be reckoned based on a dimensionless parameter defined as the 'relative duration'. Examples of different load tests are given for illustration of the different methods currently in use.

Jan 1, 1997

By Aly M. Mohammad

State and federal agencies during rehabilitation of existing bridges may require the existing bridges to be evaluated under seismic conditions. If the bridge does not perform under the seismic event, the bridge may require seismic retrofitting. Bridges are classified as: Critical, Essential, and Others according to their importance. Geotechnical considerations play a major role in evaluating the bridge behavior under a seismic event. Subsurface conditions influence the magnitude of ground acceleration and hence the forces and moments on the superstructure. This paper will provide a detailed description of the geotechnical aspects associated with the seismic retrofit evaluation for the 12th Street and 14th Street Viaducts located in Jersey City, New Jersey. The paper will also present a description of the geotechnical investigation program including seismic cross-hole surveys to determine the dynamic soil parameters, including the results of site-specific response spectra for both the 475 and 2475-year events. Liquefaction assessment methodology utilizing an equivalent factor of safety will also be described and the design method used will be summarized. In general, the pile foundation is modeled as 6x6 foundation stiffness matrix with 36 stiffness coefficients at the center of the pile cap. The seismic loading on the foundation is evaluated in a pseudo-static analysis, where the dynamic earthquake-induced loads are presented by static forces and moments. The computer program FB Pier was used to evaluate the foundation stiffness. The moments, axial loads, and shear are input into the FB Pier model. The stiffness of the foundation is determined and the results are then input into the Structural model to determine new forces and displacements. Adjustments are made until the loads are compatible with the stiffness used. The understanding of the geotechnical conditions at the 12th Street and 14th Street Viaducts and the coordination between the Bridge and Geotechnical Engineers were able to provide significant cost saving to the Owner. The Design Engineers were able to retrofit the existing Viaduct foundations with reasonable number of additional piles. It is believed that the results and finding presented in this paper will benefit both the Bridge Engineers and Geotechnical Engineers by highlighting the importance of interaction between the two disciplines.

Jan 1, 2006

By W. F. Van Impe

The design of piles and of pile groups has remarkably progressed over the past two decades. The in­creasing complexity of the building concept implements a more rational approach of the deep foundation capacity and its interaction with the structure. Moreover, the understanding of the soil characteristics relevant to deep foundation behaviour, is continuously in progress because soil parameters are always more accurately determined; which also contributed a lot to the recent developments in pile capacity design. At last, due to the increasing sensitivity of buildings to deformations, continuous attention must be also paid to pile group settlements. The aim of this report is to discuss some of the mentioned more important pile design developments.

Jan 1, 1994

By Arash Khosravifar, Matt Steffan

An expansion of the City of Klamath Falls Wastewater Treatment plant required geotechnical seismic hazard evaluations and deep foundation design. The site is located on the shore of Lake Ewauna and is underlain by diatom rich lake deposits. Diatomaceous soils exhibit unique engineering properties that are not well understood. Cyclic Direct Simple Shear (CDSS) testing was performed on three undisturbed samples to evaluate cyclic and post-cyclic properties of the diatomaceous soils. Results from the CDSS testing indicated that the soils would not liquefy in the classical sense, though cyclic softening behavior was observed. The CDSS results were used to develop a Cyclic Resistance Ratio curve for the diatomaceous soil to compare with clean sand liquefaction curves. Seismic lateral pile capacities were developed using two approaches. One approach used conventional p-multipliers for liquefied soil and modified them to reflect expected excess pore pressure ratios. The other approach applied residual strength and fifty percent strain values from post-cyclic monotonic shear testing. A lateral spread hazard zone was identified along the Lake shoreline and reduced, seismic lateral pile capacities were recommended. The objective of this paper is to report the seismic design considerations for this project in a unique geologic and seismic setting. INTRODUCTION The engineering properties of diatomaceous soils have rarely been studied and the cyclic behavior under seismic loading is generally unknown. Some of the critical geotechnical uncertainties of diatomaceous behavior include potential for large consolidation settlement, influence of irrecoverable strains due to diatom particle crushing, shear strength (peak and residual), and cyclic properties. This paper presents results of cyclic shear testing, seismic evaluations and seismic lateral pile design in diatomaceous soils performed for the expansion of a waste water treatment plant in the city of Klamath Falls, Oregon, site of the largest recorded earthquake in Oregon’s history. The expansion consisted of adding six new facilities at the existing Plant including influent pump station (IPS) and headworks, aeration basin, tertiary treatment, and other buildings. The IPS/headworks and aeration basin will be founded approximately 15 feet below ground. The other buildings will be founded at grade. The existing facilities are supported by timber piles that penetrate the surficial diatomaceous soils and terminate on a hard underlying deposit. Figure 1 shows the site plan and proposed additions.

Jan 1, 2018

By Giovanni A. Bonita

The new Embassy of the Peoples Republic of China in the United States (Chinese Embassy) is located in the Embassy Row portion of Northwest Washington DC. The 475,000 ft2 (44,125 m2) structure has five levels below ground and four above, making it the largest embassy in Washington DC. The structure approaches the property line on all sides, and is immediately adjacent to several foreign embassies and a secure U.S. Federal Building. A vertical soil nail wall was used as the primary support of excavation (SOE) system for the project. The soil nail wall was irregularly shaped, benched in areas, and reached total heights up to 98 feet (29.9 m). The soil nail and shotcrete system consisted of approximately 1,600 soil nails and 50,000 square feet (4,645 m2) of exposed shotcrete wall surface. Tight excavation requirements were defined for the project due to the location of the building relative to the property line, requiring fairly precise wall positions and shotcrete tolerances. Design challenges included soft soil conditions, inside wall corners, underground utilities, and seismic impacts from blasting. The paper will focus on the design, construction, and performance of the soil nail SOE system, as well as touch on the logistical and political factors that influenced the design. The paper also notes the Value Engineering and communication approaches that were generated during construction. These efforts resulted in a significant improvement in the quality control and quality assurance exhibited on site, expedited the schedule, and led to significant cost savings to the contractors, engineer, and owner.

Jan 1, 2006

By W. H. Liu

The stability of floors of large drydocks and wagon tipper sheds at coal terminals is an important matter but quite difficult to solve. Anchors can be used to join floors to foundations thus ensuring the stability of floors by the self-weight of floors and the pull of anchors. In this paper, the author describes the structures and types of the anchors used in the floors of the drydock in Beihai Shipyard and the wagon tipper shed at Shijiu Port, both in Shandong Province China, the determination of bearing capacity of anchors in rock bed of highly weathered granite, the comparison between prestressed anchors and non-prestressed anchors, the construction technology of anchors and the analysis of field experimental data.

Jan 1, 2010

By James J. Anderson

In this talk I will report on an effort to reassess the risk of pile driving to juvenile salmonids migrating through Puget Sound. The study was motivated by the concern of the construction industry that provisions restricting pile driving during the spring migration is resulting in an unbalanced burden to the industry. In simple terms the industry wants to know if some construction can be conducted in the spring without harming the juvenile fish. Fisheries agencies have agreed to reconsider their regulations in the context of additional studies. So, in this talk I will present some thoughts on risk assessment in general and the results of our study to assess the impact of pile driving on Snohomish River juvenile pink and chum salmon that migrate through the Navy Homeport construction site at Everett. The research, which is being carried out by the Fisheries Research Institute at the University of Washington, was planned and is supported in a joint effort including: the Washington Department Fisheries, National Marine Fisheries Services, U.S. Fish and Wildlife Service; General, Manson, and Hurlen construction companies, the Department of Transportation and a number of Puget Sound ports authorities. I will first briefly discuss the early life history of the juvenile salmon the regulations are designed to protect Second, I will outline the legal criteria required for risk regulation and some specific thoughts on how a reassessment of pile driving risk might be approached. With this basis I will report on our research and how it can be applied to a new risk assessment.

Jan 1, 1990

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

Jan 1, 2002

By Kodi Ranga Swamy, N. Sankar, M. Akhila

"Until recently, liquefaction-related studies concentrated on clean sands believing that only sands are susceptible to liquefaction. However, a few earthquakes like 1976 Tangshan earthquake, the 1989 Loma Prieta earthquake, the 1999 Kocaeli earthquake, the 2010 Chile earthquake, and the 2011 Christchurch earthquake, etc. showed that sand with fines could also liquefy. The research findings on liquefaction of silty soils are limited, and several structures constructed on such soil deposits are damaged during the past earthquakes. Some previous results of research on earthquake events show an increase of liquefaction resistance in silt soils with increase the fines content, but some report the opposite trend. This study presents the results based on undrained triaxial cyclic tests which were carried out on the fine sand with fines (0%, 10%, 20% and 40% fines). The samples were prepared at the required unit weight (Dr = 50%) and saturated by using back pressure and cell pressure increments. Each consolidated sample is subjected to cyclic loading with sinusoidal wave load form at a frequency of 1 Hz. The liquefaction resistance is evaluated in terms of cyclic stress ratio required to cause 100% pore pressure or 20% failure strain occur at 15 numbers of load cycles. Results are presented in forms of pore pressure build up and axial strain propagation plots. As the fines content increased, an increase in liquefaction potential was observed.INTRODUCTIONLiquefaction and related phenomenon have been responsible for tremendous amounts of damage all around the world. In general, the liquefaction may occur in fully saturated sands, silts and low plastic clays. When the saturated soil mass is subjected to seismic or dynamic loads, there is a sudden buildup of pore water within a short duration, and it could not dissipate which leads to reducing the effective shear strength of soil mass. In this state, the soil mass behaves like a liquid and causes large deformations, settlements, flow failures, etc. This phenomenon is called soil liquefaction. As a result, the ability of soil deposit to support the foundations of buildings, bridges, dams, etc. is reduced. Liquefiable soil also exerts a higher pressure on retaining walls.This lateral movement of soil could cause settlement of the retained soil. A sudden build-up of pore water pressure during quake also triggers landslides. Liquefaction damages of structures are commonly observed in low-lying areas near the rivers, lakes, and oceans."

Jan 1, 2017

By R. L. Xu

In this paper, the author would like to point out with figures that the building industry is one of the key industrial sectors of the national economy in China. And in the coming 15 years, the output of building construction will not in the least decrease, but increase. The requirements for building standards, quality, functions as well as physical environment will also be higher along with the incessant development of the national economy and the gradual raising of people's living standard. China is a country with a vast territory and a great, variety of physical characteristics. The topographic and engineering geotechnical conditions are complex and varies considerably from place to place. Although, in recent years, encouraging progress has been made in building construction, there still exist many problems unsolved or even not explored at all, which we have to tackle in the future design and construction of foundations. Also reviewed in this paper are the achievements attained in the past thirty odd years and the challenge we will face in the foundation engineering field in China.

Jan 1, 2010

By Richard D. Short

The Pseudo Static Pile Load Test, PLT, is a rapid method for determining pile capacity. Pile design is usually based on theoretical calculations of ultimate load capacity using soil data from a field investigation. The pile capacity is confirmed during construction by analysis of blow counts using dynamic formulae, dynamic pile monitoring, and load testing. Load testing is the most direct and reliable method of determining the actual capacity of a pile. Conventional load testing procedures, however, are time consuming and expensive. A typical load test requires installation of two to four reaction piles, construction of a high-capacity steel test frame, hydraulic jacks, and dial gauges, and will typically take one to three days per pile. Costs for load tests range from $10,000 to $20,000 per test. The Pile Load Test machine features a 25-tonne weight mounted on a mobile test frame. PLT load tests can be performed in a matter of minutes once the equipment has been mobilized to the site. This paper examines three test sites where the PLT test method was used and compares the results to conventional load test results and theoretical capacity calculations.

Jan 1, 2000

By Melvin I. Esrig

Lime Cement column stabilization of soft clay and sand in Salt Lake City, Utah and in San Francisco California is described and discussed. Stabilization permitted the construction, in a single stage, of a 14 m MSE wall on "medium" clay in Salt Lake City. It was used to mitigate the potential for liquefaction in San Francisco and to stabilize the Young Bay Mud beneath the BART extension to San Francisco Airport. These applications are described and the field measurements of performance are reported.

Jan 1, 2000

By Roger A. Archabal, Omar A. Conte, Gustavo Langoni

This international case study focuses on the rigorous geotechnical interaction and results of a soil improvement program utilized to mitigate consolidation settlements of over 1.5 m [5.0 ft]. The extreme settlement results from very deep, nearly normally consolidated clay and the required high floor loading of a new Logistics Park near Bogota, Colombia. The general subsurface conditions consist of very soft clay extending to depths beyond the 50 m [164.0 ft] explored. A required 1.2 m [3.9 ft] thick fill combined with high floor loads resulted in an applied areal load of approximately 7 ton/m2 [1300 psf] (equivalent to about 4.5m [15.0 ft] of fill). Langan recommended performing a test section to validate the initial consolidation settlement calculations and evaluate possible optimization of the prefabricated vertical drain (PVD) spacing and length. The test section sizing was designed to accurately represent the stresses at depth of the future structures. Extreme settlements of over 1.5 m [5.0 ft] in the center and large differential settlements of over 0.6 m [2.0 ft] were measured between the center and corners of the test section over a relatively short test time. Discussion on the methodology, instrumentation, measured results and future optimization are presented. The recommended soil improvement varied from the standard approaches typically utilized in the area. PROJECT LOCATION AND DESCRIPTION The project site is immediately north-northwest of the city of Bogota in the Bogota Valley. The site is bordered with, and has historically been, farming land bordered to the south by the El Rosal-Bogotá highway. The overall site encompasses about 570,000 m2 [141.0 acres] of gross area and about 484,000 m2 [119.6 acres] of net buildable area. The warehouse complex will consist of 10 very large warehouses with footprints ranging from about 15,000 m2 [3.7 acres] to 30,000 m2 [7.4 acres]. The total building area is about 210,000 m2 [51.9 acres] with most of the remaining areas being paved principal drives, truck parking or administrative parking. The topography of the site is relatively flat and close to final grade in roadway areas. However, the warehouse floors will be raised about 1.2 m [3.9 ft] (equivalent to about 2 t/m2 [370 psf] considering engineered fill) to allow for truck docking. In addition, the design floor loads are heavy and estimated to be up to 5 t/m2 [930 psf] and equivalent to about 2.5m [8.2 ft] of fill. Geotechnical conditions at the site are very weak at depths of 50 meters [165 ft] or more, with soft compressible clays comprising the majority of the soil profile. The Bogota Valley is composed in some areas of very deep alluvial deposits. These deposits have been classified as an important challenge and limitation to the development of high/heavy structures such as the project in question for many years (Orozco, 2006). Soft clay deposits have been encountered even beyond depths of 100 meters [328 ft] in some regions of the Bogota Valley (Sanz, 1994). Extreme settlements can be expected if extensive and high permanent loads (above preconsolidation stress levels) are supported in these thick alluvial deposits.

Jan 1, 2018

By W. Tom Witherspoon

Many Engineers are skeptical and cautious about skin friction factors for the portion of drilled piers where temporary casing is used. This has led Texas engineers in many cases to eliminate skin friction values for the cased section, which necessitates deepening the drilled shaft to compensate for the loss in the cased section. This paper has provided field test data that supports inclusion of skin friction in the temporarily cased hole section as a contributing factor in total axial capacity as comparable to open hole shafts of the same diameter. Reasons for the resultant friction values are provided including; remolding of the cased clay section and the increased pier circumference necessitated by the oversized casing required for adherence to the engineers shaft diameter specification.

Jan 1, 2009

By Marius B. Wechsler

There are considered deep piles which are fixed in blocks of rotating machinery foundations. A mathematical background is developed for determining the behavior of this kind of piles for motions caused by horizontal and vertical oscillations, as well as by roc-king and twisting. It is assumed that the piles come across a top soil layer of depth c, not capable of lateral support, and penetrate over a length b, in a bottom firm soil layer, or in a bottom soft soil layer in which vibrations can produce voids around the piles. With respect to b and c, as well as to the elastic properties of piles and soils, the analysis leads to the maximum bending moments and shear forces subjecting the piles, to the maximum lateral bearing on the bottom soil layer, as well as to the deflection of the pile and the displacement of the foundation block. The results of the performed analysis can be applied to seismic loads too, and they are illustrated by a numerical example.

Jan 1, 1987

By Nino Catalano

The combination of two top levels of cross-lot braces designed and installed to act as a truss, and vertical post-tensioning of the panels allow the unbraced excavation of a 36' span. Philosophy of Excavation Support System The excavation of interest is for the cut-and-cover box sections of the southern approach to the Third Harbor Tunnel, which is part of the Central Artery/Tunnel project in Boston, Massachusetts. The 60' deep excavation is located very close to an existing building which is supported by piles, as shown in Figure 1. Therefore, it was necessary to minimize ground movement which may damage the building.

Jan 1, 1994

By David R. Beadman

This paper discusses how modern techniques of design and construction were used to create the deep stations for the Copenhagen Metro. The deep stations are located in small squares within the city adjacent to many old and sensitive buildings. The architectural design provides a large open atrium to allow natural light to reach the column free platforms to give the citizens of Copenhagen a feeling of safety and security and encourage them to use the Metro. The design and construction contract was undertaken using the relatively new and untried Eurocodes. The resulting stations set new standards of design for underground metros and have pushed forward the frontiers of what is appropriate construction practice to protect the existing and enhance the future environment.

Jan 1, 2000