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By Hanlong Liu

The construction process and load-bearing behaviors of Cast-in-place Concrete Thin-wall Pipe Piles are analyzed based on its application on Yan-Tong Expressway project. The low strain test, static load test and field excavation are also carried out. It can be concluded that the new type of pile is convenient to construction with high bearing capacity and reliable quality, which has great potential in practical engineering.

Jan 1, 2006

By Van E. Komurka

This paper presents a cost comparison of the driven pile foundations for two large Wisconsin Department of Transportation (?WisDOT?) projects in Milwaukee, Wisconsin: the Marquette Interchange South Leg, and the Canal Street Viaduct. The projects? geology is fairly similar, but their methods/approaches to pile foundation design and installation differ. Although the Marquette Interchange South Leg had deeper poor soils, its pile design was more-cost-effective than the Canal Street Viaduct?s. Potential reasons for cost differences between the projects are identified, and the effect of the different design and construction approaches on economics is discussed.

Jan 1, 2009

By Chu E. Ho

Key variables that govern the jet cutting process are examined based on fundamental theories of jet hydrodynamics and soil mechanics. Under normal conditions of jet grouting operations, lift speed and rotation speed are found to be of less importance than the depth of jetting, nozzle pressure, nozzle diameter, and the soil bearing resistance, with regards to their influence on jet cutting distance. An analytical equation linking the governing variables is proposed, which allows for the possibility of evaluating column diameters achievable in different ground conditions based on theoretical calculations. When used in conjunction with shallow jet grouting field trials, the equation can provide a means for extrapolating trial results to conditions at actual depths for production jet grouting.

Jan 1, 2006

By J. Pei

The studies of dynamic measurements using stress wave theory has commenced in China. This paper introduces some practical experiences using "CASE method" in Shanghai showing applications of dynamic measurement to determine ultimate bearing capacity of pile, the change of capacity due to set up, determining the optimum bearing layer during pile driving, the efficiency of hammer system and integrity of pile and discussions of method concered.

Jan 1, 2010

By Geoffrey Birch

A skilled and efficient workforce is a pre-requisite for the success of modern construction companies. The drive for improved performance, innovation and best value must be matched by the enhanced skills of the construction personnel. Training has been accepted as one of the essential cost effective elements to achieve these goals. The foundation industry demands particular specialist skills and requires focused training for its dedicated operatives. The introduction and development of specific training qualifications for the foundation sector is providing significant benefits.

Jan 1, 2000

By Greg Nutson, Jeremy Butkovich, Bill Perkins, Hollie Ellis, Paul Bott

"Dynamic soil-structure interaction (DSSI) analyses are becoming more common in bridge designs, especially in seismically active areas. Because of its proximity to two active fault zones, the Evergreen Point west approach bridge replacement will be base isolated, and will be designed using DSSI. The project team completed two independent bridge designs to satisfy peer review requirements. The designs required substantial characterization of the soil dynamic behavior using both laboratory and in-situ testing. The analyses made use of earthquake time histories spectrally matched to conditional mean spectra. This led to reduced, and more realistic seismic demands on the structure, compared to conventional uniform hazard spectrum matching. The bridge analyses suggest that the preliminary bridge design is relatively conservative. This will allow the design team to potentially reduce shaft/column diameters and reinforcement. The design team estimates that the dynamic analysis design could represent a net savings of around $60 to $90 million compared to a conventional design.INTRODUCTIONThe Evergreen Point Bridge conveys State Route (SR) 520 2.6 miles (4.2 kilometers [km]) from Seattle to Medina across Lake Washington. The bridge is located in a seismically active area, and the Washington State Department of Transportation (WSDOT) has determined that the western half of the 1960s-era bridge (the “west approach”) is vulnerable to earthquake damage. WSDOT has begun preliminary design to replace the west approach bridge.The west approach extends about 6,100 feet (1,900 meters [m]) east from Seattle’s Montlake neighborhood, over Union Bay and Foster Island, then into Lake Washington proper (Figure 1). Approximately 5,600 feet (1,700 m) of the replacement bridge would be constructed over water. Subsurface conditions along the bridge alignment consist of 5 to 80 feet (2 to 24 m) of very soft peat and clay, over very dense/hard sand and clay. Multiple pile supported columns support the existing bridge. The new bridge would be supported by 8- to 10- foot-diameter (2.4 to 3.0 m) drilled shafts that extend about 50 feet (15 m) into the underlying very dense/hard soil. To reduce seismic demands on the bridge superstructure, WSDOT has decided to incorporate a base-isolation system into the bridge design."

Jan 1, 2017

By Mandy Korff

Walls consisting of CFA-piles are often used for vertical cut offs for building pits. Several methods of installation and geometry may be used and sizes, depths and strengths of walls necessary vary widely. Based on experience with secant CFA-pile walls in The Netherlands, requirements for this type of wall can be set with a risk management view to it. This paper describes those requirements, based on specific local conditions.

Jan 1, 2006

By Mostafa Mossaad, Ali Helwa, Manal Salem

Support of excavation (SOE) design practice tends to model SOE elements using two-dimensional (2D) analyses to avoid the complexity associated with three-dimensional (3D) analyses. Such practice overlooks soil arching in the horizontal plane and prevents designers from accounting for elements such as capping beams as part of the statical system. This study simulates square excavations supported by cantilever slurry walls in dry cohesionless soil using 2D and 3D finite element (FE) models. First, side support wall behavior is compared from 2D and 3D FE models for variable excavation length to depth (L/H) ratios. Second, the effect of slurry wall lateral bending stiffness on wall behavior is studied by modeling the wall using plate element with isotropic and anisotropic wall stiffness. Finally, the sensitivity of cantilever wall behavior to the presence of capping beam is illustrated. The study concludes that unbraced excavations with L/H ratios greater than 5 almost resemble plane-strain conditions. Slurry walls are better simulated in 3D FE models by dividing the plate element into discrete panels or by assigning anisotropic bending stiffness to the plate element. Finally, the presence of capping beam affects the behavior of cantilever walls resulting in reduction of deflections and redistribution of bending moments. INTRODCUTION Support of excavation (SOE) design practice ranges in complexity from conducting simple hand calculations to performing three dimensional numerical modeling depending on several factors among which is the geometry of the design problem. This paper addresses walls that are designed using numerical modeling, and discusses the factors governing the choice of the most suitable modeling approach. It has been believed for a while that modeling excavations using 2D numerical models would lead to a more conservative solution, which turned out to be incorrect in specific cases. This paper attempts to describe cases where 2D finite element modeling could be on the conservative side and other cases where it could be less conservative than the more complex 3D modeling.

Jan 1, 2018

By Alec C. Bloem

A 55' deep excavation encompassing almost a city block in London, Ontario required a lateral earth retention system to provide both temporary excavation support and a permanent groundwater cut-off wall for a proposed office complex. The system selected was an interlocking Drilled Shaft wall with 3-4 levels of tiebacks. The specifications required the system to be designed for movements or settlements around the excavation of ¼" max. Design to be by the Contractor with design parameters and a comprehensive soils report provided. An extensive system of instrumentation in the form of inclinometers and survey targets were used to monitor vertical and horizontal movements of the shoring system and adjacent properties. Introduction The project, One London Place, is a two phase office tower development in downtown London, Ontario. Phase one consists of a 24 storey office tower on the northwest part of the site, with five levels of below ground parking over the entire site "Figure 1". A second office tower will be constructed at a future date.

Jan 1, 1991

By JO Choi

Jet-grouting method is a useful technique to reinforce foundations on relatively soft or vulnerable soil layers such as fractured zone and stratum with cavities. Although jet-grouting has been widely applied to various field works, a reliable design standard has not been established yet. A number of model tests were performed to investigate end bearing behaviors of piles reinforced by jet-grouting. It was concluded that end bearing capacity was increased in proportion to uniaxial compressive strength of grout column. Based on the test results, the design criteria for the end bearing capacity were suggested.

Jan 1, 2006

[ENGLISH active earth pressure adapter additive adhesion admixture, addition adsorbed water aggregate air air entrainment air hose allowable bearing value allowable pile bearing load]

Jan 1, 1994

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 R. G. Shen

The relation curve of strain and acceleration is presented in this paper. The steel pipe pile of 609.6 mm in external diameter driven by IDH-45 diesel motor hammer on the esturial shoal of Yangtze River. The ultimate bearing capacity of pile is analyzed by one dimensional wave equation and the effect of computational parameters of the equation is discussed.

Jan 1, 2010

By David H. Sanders, Ramin Motamed, Fahim M. Bhuiyan, Raj V. Siddharthan

Large-diameter drilled shafts (DS) are a critical part of a seismic-resistant system, and therefore it is important to be able to accurately model lateral resistance. To undertake the lateral load analysis of largediameter DS, a finite-difference p-y analysis program, NVShaft, is being developed at the University of Nevada Reno. Validation of the new program involved numerous p-y analyses using commercially available programs. Subsequent comparisons suggested the program's ability to yield reasonable predictions for typical diameter DS. Based on the I-15/US 95 load test program carried out in Las Vegas, NV, this study presents the evaluation of NVShaft in Nevada’s subsurface condition. Lateral load analyses of a 2 ft and an 8 ft diameter DS were attempted using NVShaft. The location of the applied lateral loads and the presence of cemented soil-layers were incorporated in the modeling. A good agreement between NVShaft prediction and the measured response was found for the 2 ft diameter DS. For the 8 ft diameter DS, a stiffer response was predicted. The inspections of the moment-curvature characteristics at different load levels suggested cracked response of the concrete due to prior axial load testing may be one of the reasons behind the deviation.

By Michael J. Brown

Load testing is important for controlling the quality of piled foundations. The Statnamic test is an alternative to existing testing methods with a load duration that lies between that for static and dynamic tests. Current methods of analysis offer excellent correlation between static and Statnamic tests for coarse-grained soils but often over-predict the capacity for fine-grained soils. Thus a calibration chamber is being used to produce instrumented beds of clay with reproducible properties. A model pile placed in the beds can be loaded at varying rates using a computer controlled servo-hydraulic system. Results from the modelling will be used to improve methods of analysis and govern the design of a full-scale study. Initial results suggest the rate effect can be represented by a power law relating pile velocity and resistance. Statnamic loading of the model pile produced large negative pore pressures in the clay bed.

Jan 1, 2002

By A. Mazzucato

This paper presents the experimental results of driving and load tests on an instrumented pile driven into a test pit filled with fine homogeneous sand.

Jan 1, 2010

By Marie-Pierre Bourdouxhe-Barnich

Since 1997, in partnership with the Laboratoire Central des Ponts et Chaussées in Strasbourg, ProfilARBED has been carrying out a vast study to qualify the improvements jetting can make to vibratory driving of steel sheet piles, and to understand its effect on the surrounding ground and on the sheet piles themselves. The process basically involves discharging a fluid (mostly water, sometimes in association with air) at controlled pressure and/or flow rate near the toe of the sheet pile being driven. The steel jetting pipes are attached to the sheet pile and are connected to the pumps by hoses. The jet of fluid loosens the soil, thus reducing the resistance at the toe of the sheet pile. Depending on ground conditions, the fluid that flows along the pile can reduce skin friction. Four soil types were involved in our experiments. Each site was instrumented: the driving parameters and the geotechnical characteristics of the soil before and after vibratory driving and jetting-assisted driving were recorded. Each test provided its own particular information which contributes to overall thinking on the matter and is of help to project managers who are often confronted with rapid driving to the final depth.

Jan 1, 2002

By Bengt H. Fellenius

"ABSTRACTAn example from a guidelines document for the Eurocode is discussed that addresses design for geotechnical strength of piled foundations in settling soil, generating drag force and downdrag. A modified example of geotechnical response is then analyzed in a failure mode, Ultimate Limit States (ULS), and stationary long-term state, Serviceable Limit States (SLS). It is shown that the Eurocode principles, when applied to correctly determined forces, results in an irrational and costly design. The results of the analysis of the modified example are applied to eight different codes pertaining to piled foundations from USA, Canada, Europe, and other countries. Several of the codes require that the drag force be included as a load in a ULS design, which an absurd and costly requirement, in some codes, in one case made even worse by combining drag force with live load. A major weakness of almost all codes is their minimal treatment and sometimes total absence of aspects of settlement of piled foundation. In contrast, my main argument is that design for capacity, whether in working stress approach, or by LFRD or ULS approaches, is not always safe unless a thorough settlement analysis shows that the design also meets the requirements of the SLS.1. INTRODUCTIONFirst, there were analysis, design, and construction establishing a State-of-Practice, SOP. Then, came codes and specifications summarizing the SOP, as interpreted by a committee. When the state-of-art, SOA, was not understood by that SOP-interpreting committee, the codes and specifications are uneconomical and, sometimes, also unsafe.The paper first presents an example quoted from two commentaries on the Eurocode 7 on design for geotechnical strength by the Eurocode (1997). The example is then modified to a more realistic case and analyzed in failure mode (ultimate limit states, ULS) and in the context of settlement (serviceability limit states, SLS). The analysis results are then applied to eight codes addressing piled foundation design and changes necessary for the referenced codes and specifications to be closer to the SOA are identified."

Jan 1, 2014

By Marco D. Boscardin, Benjamin H. MacKinney, Kenneth R. Allard, Kenneth A. Pidgeon, Adriane G. Boscardin

This paper presents a case history for a unique application of a system of vertical micropiles with horizontal soil nail bracing and shotcrete facing for underpinning. The system was used to support and protect an existing 2-story hospital building during demolition and renovation. The goal was to limit building movements and have the building remain in use during construction of an abutting addition. Soils at the site consisted of clean, loose to dense, sand and gravel. The original underpinning design was revised after the initial excavation revealed unsuitable soil conditions for traditional underpinning pits. An alternative system consisting of vertical micropiles (hollow bars) through the footing, combined with shotcrete and soil nails was proposed, accepted by the owner, and successfully constructed. Excavation depths were up to 15 feet (4.6 m) below the existing footings. Wall movements were monitored at regular, horizontal and vertical intervals along the hospital wall, and less than 0.6 inches (15 mm) of settlement and 0.1 inches (3 mm) of horizontal displacement throughout underpinning and construction were reported. The challenges with the original proposed support of excavation design and other alternative approaches considered will also be discussed.

Oct 1, 2022

By S. Narasimha Rao

Bored cast in situ piles are highly susceptible to construction defects like necking, discontinuity in concreting, poor compaction of concrete, improper end bearing condition due to inadequate cleaning of bore hole, exposure of reinforcement, segregation of concrete etc. There is a necessity to understand the behavior of piles so as to design effective foundation system. In this paper investigations of two field cases were discussed to bring out the effect of defective piles. In one case improper end bearing has been discussed for a concrete pile of length of 45m and diameter equal to 1.2 m and is reinforced with 32 no's of 28mm diameter steel bars and in another case necking of the pile has been discussed. Further model piles with preformed defects have been tested in laboratory to bring out the influence of defective piles.

Jan 1, 1996