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By Upendra L. Karna

The pile capacity gain with time evaluated and implemented for the construction of the Route 21 Viaduct in Newark, NJ, U.S.A is discussed in this paper. The project consisted of the replacement of more than 3.2 km of viaduct and ramps. The project site consists of thick residual materials deposited by the Wisconsin Glacier over sedimentary rocks. The upper portion is glacial-lacustrine deposit underlain by marginal morainic till and stratified drift. Subsurface investigations identified significant variations in layer thickness and grain size consistency. The site was characterized into 4 Soil types, based on subsurface soil behavior. Closed end 600 mm and 450 mm diameter driven pipe piles were used for the foundation. Loading tests conducted during an advanced construction contract, established that a significant soil set-up could be expected. For the first construction contract, a pilot loading test program consisting of 112 dynamic loading tests and 77 re-strikes (at 2 to 4 weeks) using the PDA (Pile Driving Analyzer) with CAPWAP (Case Pile Wave Analyses Program) was conducted to establish the soil set-up behavior. Nine (9) quick static loading tests were conducted to substantiate the long-term pile capacity. Based on the loading test results, average set-up factors were established and utilized for developing production pile driving criteria. Bearing resistance with depth was analyzed and reviewed. The set-up factors varied significantly, ranging from 1.05 to 1.89, and averaged about 1.30. Conclusions are derived. Set-up factors behavior for each soil type plotted by linear regression are presented and discussed. An appropriate set-up with time relationship for a glacial soil is suggested.

Jan 1, 2006

Jan 1, 2000

By Shachar Magali

This article describes two new concepts regarding the CFA (Auger Cast) piles. The first one, MALI Effect, is an approach to control the casting phase, while the second one, NETA Shear, is a technique which converts the drilling rig into a geo-mechanical tool. We look upon the system of the auger and the ground as a piston inside a cylinder. When concrete (grout) is pumped into that system, an up lift force is generated (We call that force MALI Effect). That up lift force reduces the needed tension in the pull up cable. By analyzing the tension force in the cable we detect the up lift force of the concrete. That pushup force is the product of the real concrete pressure at the bottom of the auger by the area of that bottom. As the area is known, the real pressure is accurately calculated. A control loop which is based on MALI Effect is very sensitive, precise, objective, reliable and easy to be used. All the process is based on pure real physical measurements. The system has no assumptions, no comparisons, no parameters, no zeroing and no adjustments. When we penetrate into the ground like a theoretical screw, for about a meter in depth, and then brake the main cable while rotating the auger, a set of forces generates. As the auger tends to keep penetration, but the cable holds it - a tension force develops (We call that force NETA Shear). Analysis of that tension force shows that it relates to the ultimate shearing capacity of the ground.

Jan 1, 2000

By Bernardo J. Jiménez Vega, Edy L. T. Montalvan PhD

The experience gained during more than 900 Crosshole Sonic Logging (CSL) tests on drilled shafts shows the importance of establishing proper project acceptance and repair protocols. Drilled shaft evaluation is a multidisciplinary task that should not be left solely to the outcome of the CSL test. This test allows to characterize and delimit areas of different qualities of concrete, and it is important that all the interested parties understand the difference between flaws and defects. The information presented here is intended to give a guideline to contractors, inspectors, engineers, owners and clients on how to deal with acceptance and remediation of defective drilled shafts, detected using CSL tests. A database of flaws is presented depending on their location, intensity and remediation method. Procedures that allow the flaws to be analyzed are presented in order to dismiss or classify them as defects. In many cases, the CSL test may indicate an anomaly, but by coring the concrete and analyzing the structural demands and conditions, the flaw can be classified as non-severe. When flaws are classified as defects, their repair will depend on the area where they are located in the drilled shaft pile. In this document two procedures are described for repairing defects depending on their location. For defects in the drilled shaft head area, the procedure takes into account the interaction between the new and old concrete. For repairing the middle zone of the drilled shaft by grouting, the major concerns are the difficulty of accessing through the drilled shaft at deep depths and the communication between boreholes. For defects at the drilled shaft tip, two proposed remediation methods are presented. Finally, tomography tests are presented to compare the effectiveness of remediation by grouting.

Oct 1, 2022

By Bernardo J. Jiménez Vega, Edy L. T. Montalvan

During the last phase of the Circunvalacion Norte project in San Jose, Costa Rica, preliminary designs for an underpass structure of over 16 km (10 miles) considered drilled shafts as an earth retaining system. Since the project’s execution was delayed and close to the deadline, it was necessary to optimize this structure, with the drilled shafts being the most critical aspect. The key element in order to obtain an improved design was characterizing the job site with a specific site study for seismic demand, and the use of advanced numerical modelling, considering soil-structure interaction. The site investigation comprised the CPT, PMT, MASW geophysical tests, deep exploration drilling, and triaxial compression tests. The terrain was modeled using an advanced constitutive model with hardening plasticity calibrated from the triaxial tests. Plaxis software was used to calibrate the seismic model for the terrain and for the dynamic analysis. Two conditions were considered for the retaining structure: free-head and fixed head. A parametric study with drilled shafts of 1.0 m (3.3 ft) and 1.2 m (3.9 ft) in diameter, and center-to-center spacing of 1.3 m (4.3 ft) and 3.0 m (9.8 ft) was conducted in order to obtain an optimized structure. For each condition of the drilled shaft wall, the computed deformations were compared for two spectrum designs: site-specific spectrum and seismic code generic spectrum. Finally, a dynamic analysis was performed to check the performance of the drilled shafts with optimized spacing using a control earthquake. Based upon seismic performance curves, the analysis showed the possibility of greater spacing for the drilled shafts compared to the original design, obtaining a 32% reduction in the total length of the drilled shafts in the project.

Oct 1, 2022

By D. Kolymbas

A simple formula is introduced which allows the evaluation of dynamic pile tests. The following case is considered: The pile top is dynamically loaded by an impact. The velocity v of the pile top is recorded over the time. Let v1 and v2 be the first and the second maximum of this curve. Then, the pile bearing capacity (resulting from ideally plastic resistance at the pile wall and at the tip) can be set approximately equal to Z(v1- ½ v2), where Z is the impedance of the pile cross section. Due to the assumption of ideal plastic resistances, radiation damping needs not be taken into account. Material damping may be important in rate sensitive soils (such as clay, even if it is highly overconsolidated). A simple correction procedure for material damping is proposed.

Jan 1, 1989

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 Michael D. Justason

This paper details the static and Statnamic load testing on a 600 mm square pre-stressed concrete pile. The pile was located at Pier 15 on the 20 million-dollar Bayou Chico Bridge Project in Pensacola, Florida. The pile was 10.5 meters long and had a design load of 1.3 MN. Three static load test cycles were performed in November, 1996. The Statnamic load test was performed in January, 1997. The Davisson Failure load of the first cycle of the static test was 3.7 MN, and the Davisson Failure load of the Statnamic test was 3.2 MN. The load-displacement curves for the two types of tests were very similar, indicating that the Statnamic load test performed well in the sandy soils. Strain gauges embedded in the pile showed 35% skin friction and 65% end bearing for both test methods. Strain gauges were located at equal spacing at five elevations in the pile. A toe accelerometer verified the rigid body assumption of the Unloading Point Method currently used in the analysis of Statnamic load tests. The data collected from the pile instrumentation was of excellent quality and represents some of the best research to date comparing static and Statnamic load tests.

Jan 1, 1997

By Richard J. Hartman

Current design practice is to select steel sheet piling sections using sufficient section modulus and yield strength to resist the calculated bending moment. Thus, section modulus is the only property of the sheet pile cross section used in the selection process. Full scale laboratory testing documented that section modulus alone is insufficient to predict the strength of sheet piling. During testing, sheet pile sections with equivalent section modulus exhibited as much as 75 percent difference in load resisting capacity. Analytical study following the testing established that, in addition to the traditional longitudinal (vertical) stress in sheet piling, transverse (horizontal) stresses are also present. Transverse stresses reduce the ability of the sheet piling to function in the intended manner. It was found that transverse stresses result from the pressure applied by soil and water and that the capacity of the sheet piling diminishes with increased pressure. All sheet piling is subject to this behavior. This paper describes the testing and the results and establishes that a problem exists. A two dimensional procedure is described that assists in evaluating transverse stresses and their effect on sheet pile capacity. A method of creating design aids for use by engineers is illustrated.

Jan 1, 2006

By Y. K. Wong

This paper describes in detail various problems concerning the construction of a pile-raft foundation supporting a 42-storey tower block. The subsurface generally consists of highly weathered sedimentary rock. A comprehensive instrumentation program is implemented to monitor the behaviour of the foundation system throughout the construction period of the superstructure. Instrumentation observations are highlighted in the second half of the paper.

Jan 1, 2010

By Ingemar Hermansson, Thomas Bjerendal, Mattias Grävare, Carl-John Grävare

"AbstractHigh strain dynamic pile tests (HSDPT) on driven piles have been carried out on a routine basis in Sweden for more than 30 years. The Swedish Commission on Pile research established, in the early 1980s, safety factors based on the percentage of piles tested. The safety factors could then be reduced, creating economic incentives for the contractor to carry out testing.Energy formulas adopted by our neighbour countries, Norway and Denmark, were not accepted in Sweden as a reliable method since the dynamic testing method was considered to be a more scientific and reliable method. It has become almost the only in-situ method used to verify geotechnical bearing capacity on driven piles.The typical Swedish geology of soft soils overlaying very hard strata makes it possible to verify high design loads, typically 20 kN per cm2 of pile cross sectional area for steel piles and 1,5 kN per cm2 for concrete piles.Conventionally a certain percentage of the piles have been tested in Sweden. The EC7, on the other hand states a number of piles to be tested, regardless of the total number of piles. The Swedish NA (National Annex) states a maximum distance between tested piles, which results in better distribution of the test piles over the foundation.For shaft-bearing piles in soft clays, dynamic pile tests have to be correlated by static load tests.Historical backgroundOn a research basis stress-wave measurements have been carried out for a long time in Sweden. One example is a project in the city of Gothenburg, conducted by Fellenius and Pejrud (1964). Strain gauges were glued on the reinforcement bars in 60 m long, precast concrete piles at 3 m and 25 m above the pile tip respectively. Evaluation was done with different methods such as dynamic formulas,stress-wave measurements and in addition compared with static load tests.In the 1975 Building Code in Sweden, driving criteria for concrete piles based on stress-wave theory were introduced, as summarized in Table 1. The driving criteria are intended for 3 and 4 tonne gravity hammers. For hydraulic rigs, which have free-falling hammers, the drop height indicated should be reduced to 80 % of the values in the table. The criteria were considered to include a safety factor of 3,0. For 330 - 450 kN pile load, pile with a standard a cross sectional area of 235 mm x 235 mm was used. For 600 kN load, the standard cross sectional area was 275 mm x 275 mm."

Jan 1, 2014

By Ketan H. Trivedi

This paper describes the method of analyses used for the design of temporary and permanent Secant Pile Walls, describes various aspects of construction including, guide walls, sequence of pile installation, plan alignment and verticality tolerance, methods of drilling (auger, wash boring, cased and open holes), lateral bracing for secant piles, cutting of keys in secant pile walls for the connection of permanent floor slabs, sealing of water leaks and waterproofing. The paper concludes with a brief case history of a secant pile wall project recently constructed in New York City.

Jan 1, 2006

By R. Bellotti

The theory of cavity expansion in an infinite frictional soil mass whose strength is represented by a curved Mohr-Coulomb failure envelope has been used to predict with some confidence the cone resistance of a clean dry sand. Experimental data were obtained from cone penetration and pressuremeter tests on two sands, conducted in a large calibration chamber (CC) under carefully controlled placement and boundary conditions. A plane strain bearing capacity theory was developed, and to convert the results to axi-symmetric conditions, an empirical "shape factor" was used. In the paper, the theoretical background, experimental data, calculation procedure, and the results of the analysis are presented. In general, a reasonable validation of the cavity expansion approach to the bearing capacity of deep foundations has been obtained.

Jan 1, 1987

By Terrence M. Carroll, Chu E. Ho, Dimitrios Niarchos

"Construction of the new extension to Terminal 4 at John F Kennedy International Airport in Queens, New York involved the application of tapered piles for foundation support. Initial design based on past load testing experience had indicated that a pile depth of 65 feet was necessary to achieve a capacity of 394 tons. However, piles with a single length of 62 feet were ordered and installed, which led to marginal performance of the piles. This paper presents the technical considerations for mitigating the situation based on a systematic review of three preliminary pile load tests and dynamic capacity measurements on the shorter piles. Consideration was given to the long term gain in capacity of tapered piles due to set up in the Glacial Sand. The observational approach to the evaluation of piling performance adopted on this project resulted in salvaging many piles which failed to comply with the specified driving criteria. It was acknowledged that a more prudent course of action was for the Contractor to have ordered more appropriate pile lengths that allowed for potential variation in soil conditions across the site. The 4.6% saving in pile material did not warrant the effort that was required to mitigate the 39% of installed piles that did not meet the specified driving criterion.INTRODUCTIONAn expansion project at John F. Kennedy International Airport in Queens, New York involved the Phase 2 extension of Concourse B at Terminal 4. The site consists of 4 to 5 feet of pavement over about 10 feet of hydraulically placed sandy fill. Below this is a layer of marsh deposit, comprising of soft organic clay and peat, up to about 11 feet thick. Beneath the marsh deposits is a deep layer of glacial sand which extends to well over 100 feet below ground. Figure 1 shows the typical subsurface profile at the site. The new structures were supported on 223 steel tapered piles. The piles consisted of a straight steel pipe 18 inches in diameter and 0.375 inches thick, with a 25 feet long tapered bottom section (diameter varying from 18 inches down to 8 inches at the pile toe). The piles were first driven to the founding depth and subsequently in-filled with concrete. The concrete strength (fc) specified was 4,500 psi and the yield strength of the steel piles (fy) was 50 ksi. Initial pile design, based on earlier experience with static pile load testing for Phase 1 development at the same terminal, indicated that a pile length of 65 feet was necessary. However, piles with a single length of 62 feet were ordered and installed by the Contractor, leading to marginal performance of the piles. This paper presents the technical considerations for the adoption of alternative pile driving criteria, based on a systematic review of the preliminary static load test results for the present site and PDA measurements obtained during pile installation, in order to accommodate the capacity of the shorter piles."

Jan 1, 2017

By S. X. Liang

In China, the bearing capacity predictions of the pile with Stress-Wave Theory have been developed rapidly in recent years. This paper recommended a DZH-3 Pile Driving Analyzer and its relevant computer programs. Taking Qinghai Hotel Project for example, it gave their applications in the dynamic tests of large diameter cast-in-place piles.

Jan 1, 2010

By D. A. Bruce

The Deep Mixing Method is a very valuable tool for combating problems related to in situ soil treatment, improvement, and retention. Many different variations are used throughout the world, and there is a correspondingly rich technical literature on the testing and properties of the treated soil. This paper provides a synopsis of these aspects.

Jan 1, 2001

By J. D. Findlay

The demands on development in London in recent years has led to the increasing use of top down construction methods in which there is a requirement to place steel columns to high tolerances into large diameter bored piles with deep cut-offs. A number of different proposals for the sequence of construction are being suggested. The tolerances requires for the steel columns are becoming increasingly stringent. This review examines a number of basic construction proposals and comments on the problems and solutions used by foundation contractors to provide the required foundations.

Jan 1, 1989

By Thomas Domanski

Any type of deep excavation whether for Bored Piling, Diaphragm Walls or Contiguous Bored Piling Walls depends on forming a stable borehole with a defined cross-section to receive safely the permanent materials. In modern construction the excavation depth can reach well the range of 100 m and above. The diameters of the Piles reach often sizes of 2.5 m and bigger. Top casings in Bored Piles (Diaphragm Wall none) are rather short and stability below the casing, need to be secured by stabilization slurry. The boreholes need to be formed through a variety of different materials and stand open for an extended period. Without a safe stable borehole, it is impossible to produce quality products and work cost-efficient. The understanding and proper usage of a suitable slurry is a key element essential for the delivery of Foundation Elements with high quality and within a reasonable budget. The setting of mechanical and rheological parameters in specifications is necessary and helpful, but probably insufficient to embrace and control such a key element in the practical implementation of foundation construction. The proper selection, design, implementation and supervision of slurries on site requires both from Contractors and Engineers to understand how different slurries do function. Only with this knowledge the right decisions in slurry operations can be made. This talk is directed to give some help to both, Contractor’s and Engineer’s, in understanding how different type of slurries do work. (Which ones should be preferred in what kind of soils.) The better knowledge will help the Contractor to control cost and enhance production. The Engineer will be able to assist in arriving at the appropriate technical choices and include in the specifications.

Sep 1, 2022

By Yin Zongze

The pile foundation of Sutong bridge pylons is an extra large pile foundation. The length of piles is 115m, and the diameter of the piles is 2.5-2.8m. Since the traditional design method may not determine the settlement and capacity reasonably for such a large pile foundation, the finite element method is used to study stress and deformation of the foundation. The interface element is set to simulate the possible slide between piles and soil layers. The hyperbolic model is taken for soils. Parameters are determined from triaxial test first, and then modified by back analysis on basis of in-situ loading test. The computation results show that the axial force of piles changes with the location of the pile. Outer piles support greater axial force and also friction. The settlement will not be greater than 26cm. The stress and deformation of the pile cap, the abutment, are obtained too. The whole foundation is safe.

Jan 1, 2006

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