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By Gerry Houlahan

The east span of the 3.5 km long SF-Oakland Bay Bridge is supported by different types of foundations along its span. Starting from the west, its first 460 m section comprising twin concrete box-girders is supported by sands and rock on Yerba Buena Island. A 620 m long steel suspension span then bridges a 25 m deep channel that is formed in sediments overlying rock. Twin concrete box girder structures, each 2.4 km long, complete the stretch over the remainder of San Francisco Bay to the engineered earth fill landing at its east end. For most of its length, the Skyway bridges water 3 to 10 m deep over soft surficial Young Bay Mud. The foundation types include spread footings with hold-downs, steel and concrete piles that are set in drilled rock sockets up to 3 m in diameter and 2.5 m diameter steel tubular piles driven to penetrations of up to 100 m. The design and construction-related considerations are presented. The different foundation types, influences of the site geology and earthquake demands on the substructures are discussed. The seismic motions of the bridge superstructures and substructures, as well as the depth-varying soil motions, influenced the foundation design. Together with performance-based design criteria, including post-earthquake footing displacement limits, these seismic demands influenced various aspects of the foundation design, including the use of battered and vertical piles.

Jan 1, 2005

By Matteo Montesi

Deep foundation elements are often used as discrete elements in externally supported earth retaining structures such as soldier piles and lagging walls, secant/tangent pile walls, anchored walls, etc. These structures can be designed using different approaches such as conventional limit equilibrium methods, finite element/difference analyses, and soil spring (p-y) analyses which are contained in various commercially available computer programs used by engineers worldwide. Although these programs usually undergo various degree of verification and validation, users must be aware of each program’s limitations and conditions in which each design approach should or should not be used. These programs may incur difficulties when non-continuous deep foundation elements are used as part of the retaining system and in cases of non-uniform geometry where closed-form solutions are not available. Design input parameters such as passive arching width, wall-to-soil friction, and p-multipliers (pm) are not always given enough attention which may result in potential design deficiencies. This paper presents the main features of various earth retaining structure design approaches and discusses their advantages/disadvantages. The paper addresses some of the limitations and difficulties that may be faced with when utilizing non-continuous discrete deep foundation elements and identifies key elements that are sources of potential deficiencies and errors. An example comparing the design outcomes using different design approaches is presented. INTRODUCTION Earth retaining structures are used to retain soil and create or maintain a difference in ground elevation between grades in front and behind the retaining structure. Deep foundation elements have been used for decades to support earth retaining structures. Earth retaining structures that are supported by deep foundation elements are typically referred to as externally stabilized system (O’Rourke and Jones, 1990). An externally stabilized system uses an external structural element, in contrast to internally stabilized systems which rely on reinforcements installed within and extending beyond the potential failure mass. The design of externally supported retaining structures can be accomplished using different approaches, which can be challenging under certain conditions. Each approach has been discussed extensively in available literature, and is well summarized in the and Federal Highway Administration (FHWA) guidelines. The objective of this paper is to present the most widely used design approaches and discuss their limitations and difficulties in one concise and brief document, giving the reader a good source for comprehensive understanding of the various design approaches, supported by a technical example. This paper is not intended to be a comprehensive review of all available design methods and formulations available in the literature.

Jan 1, 2018

By Gustavo E. Armijo

This job was done in Morristown, NJ, with mono fluid system jet grouting for the construction of a new bank building. After the demolition of the existing two story structures, an excavation in loose sandy fill materials was necessary in order to reach the new structure basement level. Due to this jet grouting was selected as a medium to provide both excavation support and permanent underpinning, minimizing the adjacent building settlements. These two adjacent buildings were partially underpinned with a "gravity wall" made with 2 and 3 rows of secant vertical and inclined jet grout columns. Besides the classical jet grouting control methods, during the jet grouting execution, all the drilling and grouting parameters were recorded by a proprietary system called "Slogger". Additionally, after the jet grouting execution, an innovative result control technique was used by means of the application of the same parameter recording system. Some of the production columns were re-drilled and a comparison was made between the obtained drilling parameters and those obtained for the same age test columns. Under the referred existing conditions and in comparison with the conventional underpinning techniques, this project demonstrated that jet grouting, with proper execution and result control, can be faster than them and can maintain the building structural stability and act, at the same time, as a retention system minimizing the existing building settlements.

Jan 1, 2002

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 Andy Schroeder

Located in Hamilton, Ontario Canada, Berminghammer Foundation Equipment, is a manufacturer of advanced foundation equipment with 30 years of experience. The company is represented in more than 20 countries world wide, maintains an extensive Research and Development team, and has earned a reputation for finding the most practical solutions to the most challenging projects. The vertical travel lead, referred to as "VTL" system, was first developed and patented by C.W. Bermingham in the 1970's. This lead system was developed in response to the fundamental limitations of either a fixed lead or hanging lead system. The fixed lead system is well suited to level job sites with few obstructions and has the advantage of faster positioning of the lead, the hanging lead is very adaptable to different elevations and batter piles but takes much longer to position. Therefore the Vertical Travel Lead was developed to combine the advantages of fixed leads, fast and accurate positioning, with the ability to adjust the height of the lead base up or down. The VTL lead is connected to the boom by a sliding connection which allows the lead to be elevated or lowered below grade. The advantages of the VTL system were recognized by many foundation specialists and they have become the Industry standard in Canada , US Railway Construction , and many parts of the USA.

Jan 1, 1997

AUSTRALIA CHAPMAN Gary JOHN WAGSTAFF CONTSRUCTIONS PTY. LTD. 1 Ashgrove Crescent 4060 ASHGROVE BRISBANE HILLAR Jaaes Director J.A. HILLAR & ASSOCIATES 99 Woolwich Road WOOLWICH, NSW 2110 WAGSTAFF John Managing Director JOHN WAGSTAFF CONSTRUCTIONS PTY. LTD. 1 Ashgrove Crescent 4060 ASHGROVE, BRISBANE AUSTRIA FUCHSBERGER M. TECHNISCHE UNIVERSITAT INSTITUT FUR BODENMECHANIK Rechbauerstrasse 12 8010 GRAZ

Jan 1, 1994

By Peter J. Nicholson

A new method of constructing retaining walls, in-situ, prior to excavation has been developed. This "Vertical Earth Reinforcement Technique" VERT, has been demonstrated at a full scale test wall at the National Geotechnical Experimentation Site at Texas A&M University. This 10 meter high wall, was constructed of elements of soil mixing in an array that forced composite behavior between the soil mixed elements and the in-situ soils. Inclinometers and extensometers were used to verify the performance of the wall. The construction and results of the testing are presented.

Jan 1, 1998

By Fabrice Mathieu

The Cutter Soil Mixing (CSM) provides a cost effective solution for the rapid construction of retaining and cut-off walls using new equipment developed from diaphragm wall cutter technology. CSM consists of cutting and mixing drums mounted on compact hydraulic motors. Soletanche Bachy CSM has been designed to leave the space above the tool free, thereby mixing the soil efficiently during all the phases of the wall construction, with high penetration rates. The precise positioning and verticality of the wall is achieved using a kelly bar and full monitoring. Soletanche Bachy CSM is a versatile equipment which can be mounted on various carriers: pile rigs, hydraulic crane, carrier equipped with telescopic mast. The major phases of Soletanche Bachy CSM development are presented, including the results of an extensive trial carried out in Le Havre (France). The soil consists of hydraulic fill with soft soil lenses overlying sandy deposits. 20m deep panels were constructed to support a rectangular shaft. During the construction, and after its completion, the shaft was subjected to an extensive series of tests followed by a partial excavation. The paper discusses also the future development of the technique and its potential applications.

Jan 1, 2006

By Patrick Bermingham

The advancement of hydraulic impact hammers has followed the general advancement of hydraulics. The construction industry has been revolutionized by the application of hydraulics in excavators, cranes and, of course, in the hydraulic vibratory driver/extractor, which has become a standard tool. The innate ability to move a large mass with a very small displaced volume has given hydraulic power the advantage over previous power mediums. Recent development of more specialized and complex seal configurations and compounds has greatly improved the reliability and permitted the use of higher pressures in hydraulic systems.

Jan 1, 1987

By J. Nakayama

For drilling large diameter holes for deep foundations, the common and distressing difficulty of long standing has been in coping with ground containing rocky formations and boulders. Where geological formation contains weathered rock or boulders, or deep rock socket is specified, drilling equipment occasionally is found to be unable to drill through and therefore will need supplementary equipment and procedures. Incentive of the MACH Drill Development has been to realize a capable drilling system for rocks of weathered to fresh rock without losing its applicability to usual overburden. Through seven decades' experience of manufacturing and operation of boring machines, the best features of all sorts of drillhead are known such as the drag bit, wing bit, auger bit, diamond bit, rock roller bit, down-the-hole hammer bit, etc.

Jan 1, 1988

By Feng Yongxuan

Anchored sheep pile is normally used in deep excavations, many of which only require stability in accordance with Terzaghi theory. In this paper, based on the experience, new lateral earth pressure method is adopted taking account into interaction among soil, anchors and sheet piles so that a group for the project under very difficult conditions and very severe requirments, especially, for the displacements are determined according to that mentioned above. During and after construction, displacements monitoring were carried out for about four months, which was proved that there was a little difference between calculation and practice.

Jan 1, 1991

By M. Makarchian

Existing buildings sometimes experience excessive settlement under their design loads, or due to increased foundation loading, if a change of building use is required. One of the oldest and widely numerical study has been carried out of a simple idealised problem of an underpinned rigid circular foundation to better understand the behaviour of pile used for underpinning and load transfer mechanism from an existing foundation to the underpinning piles. The finite element method has been used for this analysis, with the soil treated as a two-phase elasto-plastic material. It is found that the effect of the length of the pile becomes more significant as pile length increases. As would be expected, the earlier the pile is installed, the less is the final settlement.

Jan 1, 1996

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 Peng Jiahong

With ultrasonics application during checking the large diameter cast-in-situ pile body, it is usualy applied the statistical method of probability and PSD. This paper presents a converse probabilistic-analytical method which can identify important anomalies, both strong and weak, during interfered situation. So the inhomogeneity in concrete pile may be ellectively distinguished. In order to ensure the capacity of bed rock support layer under large diameter pile, a test-in-situ is conducted to determine the compresive strength and shear force inserting rock of the support layer, so the compresive strength and modulus value of elasticity of bed rock tested will closely tally with the actual situation.

Jan 1, 1991

By Rob Jameson

"The demand for commercial and residential construction has continued to evolve across the United States over the last decade. Our markets demand larger, deeper and inherently more complex structures, located within increasingly constrained urban locations and with challenging geotechnical conditions. As project demands incrementally escalate, specialty contractors are continuously challenged to extend their state of practice. Development in the size and capabilities of construction equipment, tooling, techniques, monitoring and verification systems over the last decade has consistently allowed contractors to build larger and deeper. For support of excavation (SOE), in addition to scale, selection of the most appropriate system has been a key to success in the most challenging ground conditions. This selection process is based on sound engineering and construction practice, and also prior experience, both positive and negative. Ultimately many Owners have chosen to manage their risk of SOE construction through design-build contracts, which allows specialty constructors to optimize the balance of cost, schedule, scope and associated risk based on their local expertise. Successful implementation of a design-build methodology begins long before a contractor is selected, with identification of key project requirements and risk factors during the feasibility studies and design development phases. In these early stages of the project development, advice and budgets are frequently solicited from Specialty Contractors. The Owner, Construction Manager and Consulting Team will filter this input from multiple sources to provide their specific recommendations, develop construction documents and select the appropriate form of contracting. Only in the final stages, after award of a Design-Build Subcontract, can the successful specialty contractor directly influence risk management approach on the project. A case study is presented from Block 9 in San Francisco’s Transbay District. This project demonstrates the incremental identification, assignment and mitigation of construction risk through the planning and design build process for SOE on the deepest planned excavation in San Francisco.INTRODUCTIONThe mature urban development market in United States results in high demand for complex Support of Excavation (SOE) schemes on constrained sites. The Design-Build approach can be applied to increasingly difficult SOE challenges, combining regional specialty subcontractor knowledge and experience in order to optimize solutions for cost and schedule. The most successful applications will involve early engagement of shoring subcontractors within the project teams, during feasibility and design development stages, in order to identify key scope and risk issues, and their potential solutions. Throughout the project development, it is important to reasonably assign responsibility for construction risks amongst the project stakeholders who are best able to control them.This paper presents a case history for San Francisco’s Block 9, a well-planned and successfully executed design-build SOE project in San Francisco’s Transbay Redevelopment area. Throughout the 4 year period from the Developers initial proposal to the Redevelopment agency, through completion of excavation down to subgrade, the project team developed a series of increasingly refined SOE schemes, with corresponding scope definition and cost and schedule estimates. This program relied on early identification of key challenges and risks for the project, and evolved through multiple phases of proposals as first the General Contractor (GC) and then Specialty Shoring Subcontractor were engaged for the project. The scheme, cost and schedule refinements continued throughout construction in order to accommodate unanticipated conditions and events as they unfolded."

Jan 1, 2017

By Mark H. Balfe

Over the last decade, Fenway Park has undergone annual improvements to modernize the facility for players and fans. These renovations include the Monster Seats, the Right Field Roof expansion, a new pavilion behind home plate, expansion of the Red Sox clubhouse, additional roof seating, and concourse improvements. Retrofitting the historic ballpark to bring it up to current standards required installation of foundations to support the new structural loads for each of the alteration projects. This required evaluation of existing conditions, and in many cases augmentation of the foundations at existing columns to accommodate the structural changes to the park. New foundations, generally consisting of drilled-in micropiles, were installed in numerous configurations and conditions. Since 2003, a total of 215 drilled-in micropiles have been installed to augment various columns around the park. The micropiles range in capacity between 40 and 70 tons and are installed through Fill and Organic Soils and embedded into the dense Glaciofluvial Sand and Gravel layer. Issues and learning related to the foundation augmentation include schedule constraints (work is typically conducted during the off-season and schedule is very aggressive), encountering old/abandoned utilities or foundations, ventilation of equipment, and management of spoils during micropile installation.

Jan 1, 2011

By John E. Lens

How much trouble can narrow vertical fissures in bedrock cause on a shallow bedrock site? Enough trouble so end-bearing H-piles range between 8 and 100 feet long in a single pile cap and tiebacks range from 40 to over 100 feet long within a 10 foot wall span. Sloped bedrock surfaces also complicated the tieback installation as the drill casing followed the sloped rock surface while drilling and caused unanticipated bending (and sometimes breaking) of the drill string. Warned via pre-construction rock probes and cores reaching over 80 feet deep at the Winooski, Vermont project site, the design and construction team expected anomalies in pile driving and tieback drilling due to fissures in the bedrock filled with soil and weathered-rock. The degree of abruptness in the variability in the rock surface, and its impact on pile driving and tieback drilling were less predictable. Close monitoring of pile and tieback installation, redesign of pile caps, and lengthened tiebacks overcame these anomalous fissures. This paper shares the lessons learned for overcoming these geologic challenges to benefit designers, contractors bidding the work, and ultimately, the owner, with lower contingencies.

Jan 1, 2006

By Claudio Olalla

This paper relates to the foundation of a steel structure located at the San Martin de la Vega (Madrid) amusement park. The structure has more than 100 supports with various loading conditions, including important horizontal and uplift forces. Additionally, the settlement tolerances are very strict. A massive gypsum formation with interbedded clay layers and random solution great voids at various levels constitute the soil. The foundation design has been conditioned large enough these difficulties (load conditions and soil problems). The piling machine used was powerful to drill through the soft rock (UCS up to 11Mpa). The integrity of each pile had to be guaranteed by continuous recording of drilling and concrete pouring parameters. In order to fulfil all those conditions, a STARSOL type-piling rig was used. More than 4500 meters of piles were performed. The diameters of the piles were 450 and 550-mm and their depths varies from 6 to 23 meters. All piles were reinforced over their full length.

Jan 1, 2002

By Paul J. Lewis

Estimation of the axial side shear resistance of drilled shaft rock sockets is directly related to the unconfined compressive strength of the bedrock. Commonly, the mean unconfined compressive strength value is calculated from a range of laboratory test results and is used to estimate the side shear of the bedrock. This paper presents the results from a full scale axial load test performed on an 8.5-feet-diameter drilled shaft rock socket, and compares measured side shear values to estimated values for two different rock strata. Measured side shear values correlated well with the design value calculated for the "strong" rock stratum, but did not correlate well with the design value calculated for the "weak" rock stratum. The mean unconfined compressive strength was used to calculate the side shear in both strata, but review of the laboratory data indicates that this value may not have been appropriate for the weak stratum due to a large variation in the laboratory test results. Also included in this paper is a discussion of the subsurface conditions, the laboratory test results, and the methodology used to design the drilled shaft rock sockets for axial and lateral resistance.

Jan 1, 2005

By Mohammadreza Khanmohammadi, Kazem Fakharian

"AbstractIn driven piles, the gradual dissipation of excess pore water pressure and consequently the soil setup significantly contribute to increasing the pile capacity with time. The question is risen that how the scale differences affect the stress state variations around the pile shaft and at the pile tip? Would the CPT predictions better correlate with End-Of-Drive (EOD) or Beginning of Restrike (BOR) conditions? On the other hand, are the proposed a and ß parameters for clayey soils mostly predicting the EOD or BOR situation? The main objective of this paper is to back calculate the a and ß parameters from CPT profiles, pile Dynamic Load Tests (DLT) at the EOD and BOR as well as Static Load Tests (SLT) and evaluate how they compare with those suggested in literature. Four precast 400 mm square concrete piles driven in North Azadegan Oilfield in Khuzestan Province were selected for the comparisons. CPT test results were available from the extensive geotechnical investigation at the study site. DLT tests using PDA were carried out at EOD, 1 day and 14-day BOR on all the 4 piles. All the piles were SLT tested as well. The UniCone software was used to estimate the tip and shaft resistances using 4 methods including the Dutch, Eslami & Fellenius, LCPC and Schmertmann. The results indicate that the a-method based on the proposed values in literature has predicted a shaft capacity of 90% of the 14-day BOR. This is while the ß-method has predicted a shaft capacity equivalent to 1-day BOR results only. Therefore, both methods have under-predicted the shaft capacities compared to real capacities measured after the significant soil setup in the study area. Two of the CPT methods have underestimated, one has overestimated and one has matched the estimated 60-day capacity."

Jan 1, 2014