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By Sherrill Gardner

Vibratory drivers have been used since the 1930s to drive and extract piles. Vibratory pile drivers have the capability of significantly decreasing pile installation time, especially in granular type soils. However, they have not been widely accepted because of the uncertainty in estimating the bearing capacity of the driven pile. When driving bearing piles, the industry standard method for obtaining load carrying capacity of a pile installed with a vibratory driver is to redrive with an impact hammer. The advantage of improved productivity is lost with the redrive procedure. Currently, there is no other method to predict the capacity of these bearing piles installed with a vibratory driver. The Naval Civil Engineering Laboratory (NCEL) is making progress towards being able to estimate the bearing capacity of these piles. This paper describes field testing and corresponding analytical modeling of the vibratory driver-pile-soil system. The following sections describe the development of the numerical model and techniques for collecting field data. A discussion of the prediction of the pile driving process based on field test data is followed by suggestions as to the additional work that should be done to further verify the model to a point where it can be used with confidence.

Jan 1, 1987

By Andrew Pontecorvo, Steven Lowe, David Sposito

Buildings with large height-to-width ratios require foundations with significant uplift resistance. This paper presents a case study of the permanent rock tiedowns installed for One Manhattan West, a sixty-seven-story office building in midtown Manhattan. Site access and schedule dictated the size of the equipment for installing the tiedowns would be limited to drilling a 16 inch (406 mm) diameter hole. A three bar configuration of 3 inch (76 mm) diameter high strength threaded bars was chosen to develop an allowable capacity of 923 tons (4060 kN) per tiedown. Although the quality of the rock at the site was generally high, a challenging geologic condition emerged during the installation of one of the tiedowns requiring a creative installation procedure. Although the three bar configuration performed relatively well there are challenges with loading and testing this bar arrangement. Unlike single bar tiedowns that are typically tested with a high success rate, testing of a multiple bar system can result in some unsatisfactory results. This may be attributed to the installation challenges, difficulty loading each bar uniformly and/or the method of monitoring the test. Understanding the complexities is necessary to improve the testing results and achieve similar reliabilities of single bar systems.

By L. J. Whitworth

Five trial piles were constructed during the trial pile programme for the Birmingham International Convention Centre. In addition, trial piles have been tested on two other sites in central Birmingham. Methods of pile construction were conventional sandstone rock sockets, sleeved piles and voided piles. The results of these load tests are compared with the theoretical predicted behaviour based on the results of unconfined compressive tests of rock core taken on the Convention Centre site and on other sites in the central Birmingham area. On the basis of this work, the various design procedures are discussed.

Jan 1, 1989

By L. Z. Xie

The results of the experimental study on the static behavior of single piles subjected to repeated and reciprocating axial loadings are recommended in this paper. Tests of four full-scale single piles of two different lengths under repeated loading and those under reciprocating loading have been conducted using the slow maintained load test method. All the eight piles were instrumented with strain gages located along the shafts. The study showed that for repeated loads below a certain critical value the total displacement of the pile top approached gradually a constant value. However, any repeated load greater than the critical value resulted a residual displacement per cycle, and that the reciprocating load capacity of a pile was dependent on the ultimate bearing capacity of the pile in tension and both were in the direct ratio.

Jan 1, 2010

By Han Jie

The results of full scale plate load tests on stone columns on soft clay in coastal areas are presented in this paper. Four load tests were made, two of which were performed on the ground treated with stone columns, one on an isolated stone column and the last one on the untreated ground. For a given stress range, the settlement of the rigid plate, the stress concentration factor, and the excess pore water pressure were measured. It is found that the distribution of vertical stress beneath the rigid plate supported by the composite ground of stone columns is very different in shape from the one by the untreated ground, that the stress concentration factor has a relation with the stress level and time, that the stone columns increase the bearing capacity up to by 2 times, and that the ground stabilized by stone columns is of great advantage to keep the foundation stable.

Jan 1, 1991

By Xuhui

Pile foundations are underground projects which are carried out under complicated site conditions, so it is difficult to summarize their characteristic patterns from the everchanging practical pile foundations. In combination with theories, the paper analyses the effects of sound reinforced concrete piles and various types of defective piles on the propagations of stress waves. Through testing on prototype pile models, by use of the transient dynamic method and comprehensive analysis in both time domain and frequency domain, their reflection characteristics and patterns are acquired. In addition, discussions are carried out in combination with some real projects. Our model tests include comparison of large scale pile models of 20X20cm in cross section, 5. 0m in length respectively in air, standard sand, and natural stratum; prototype model tests of digged piles of 0. 7-1. 2m in diameter, and 18m, 30m in length; prototype model tests of bored piles of 0. 6m, 0. 8m in diameter, 12-20m in length. Test results show that no matter in air or buried in medium, the intrinsic characteristics of sound piles and various types of defective piles are fixed. In their time domain waveforms and spectral diagrams, obvious regularity are shown, which proves that the relations between the pile natures and their dynamic responses are fixed, which provide basis for correct judgement of pile soundness and natures of defective piles.

Jan 1, 1991

By P. Srinivasulu

The popular theoretical models used for assessing the dynamic behaviour of piles under vertical and lateral excitations are critically reviewed. An experimental study is presented on model piles with varying slenderness ratios. The theoretically evaluated and experimentally deduced natural frequencies and resonant amplitudes of the test pile-soil system are compared. The dynamic stiffness and damping are seen to increase with increasing slenderness of piles. Further, the damping yielded by the theory is found to be on the unconservative side.

Jan 1, 1996

By Jack Hayes

Vibrating wire strain gages have proven to be a very reliable and effective tool for the measurement of strains associated with the loading of bored piles (drilled shafts). However, when these strains are used to calculate the load, or stresses in the pile, the results can sometimes be confusing and/or difficult to interpret. This paper describes some of these situations, using examples from actual case histories, and discusses some of the difficulties associated with residual load effects, curing and temperature induced strains, load stress distribution effects, estimated modulus and area.

Jan 1, 2002

By Yong Jingrong

Based on the results of several test socketed piles in Sichuan, the mechanism of the deformation for a loaded socketed piles is investigated, and the concept of the socketed effect is proposed. The bearing capacity and settlement of socketed pile are controlled directly by socketed effect, that is an important mark different from the other types of cast-in-situ piles. According to the analysis of this effect and factors interferring it, their roles are discussed with the results of test piles. In order to increase the bearing capacity of piles, the ways and methods enhancing socketed effect are recommended.

Jan 1, 1991

By RAP Bement

Installation by vibrodrivers of sheet and bearing piles generates periodic vibrations in the surrounding ground, which have been widely measured and reported. One of the possible consequential effects of these vibrations is ground settlement caused by the compaction of loose granular soils. Vibratory compaction settlement of a range of granular soils has been studied in the laboratory using a 150mm diameter Rowe cell, which allows sample preparation and control during vibrations equivalent to conditions in the field during vibrodriving. The cell containing the soil sample was mounted on an electromagnetic shaker and vibrated at amplitudes and frequencies appropriate for soils adjacent to vibrodrivers. The changes in sample height were recorded.

Jan 1, 1996

By Rob van Dorp

Most traditional foundation designs are based on soil investigations using Standard Penetration Testing (SPT), sometimes combined with static load testing on sacrificial trial piles. However, this design approach has two major shortcomings. First, SPT data do not provide direct and continuous informa- tion about soil resistance as a function of depth. Second and more important, because of the relatively wide spacing between borehole locations, SPT soil investigations do not provide adequate information about variability of soil profile and/or soil resistance over the project area. Preliminary pile load testing on an SPT location can compen- sate for the first disadvantage but cannot address the second disadvantage. A design approach based on an adequate soil investigation campaign with Cone

May 1, 2022

By V. T. Ganpule

The effect of Sulphate and Chloride is well understood by the engineers. Most of the codes stipulate permissible limits for sulphate and chloride content in groundwater. Relatively few reference are available about the effect of organic acids on pile concrete. While executing a pile foundation work around Bombay, the authors came across the peculiar phenomenon. The routine testing of water has indicated that water is non-aggressive; however, on exposing the piles, the piles were found to be highly detonated. The testing of water on the guidelines followed by engineers associated with flow through pipes revealed that water is corrosive as per the Ryznar index concept. The present papers discussess the significance of Ryznar index in under water concreting.

Jan 1, 1996

By W. G. K. Fleming

The codification of foundation design and construction is a subject of extensive discussion in Europe and all current code proposals are based on limit state partial factoring. For simplicity, it is claimed, simplified forms of Partial Factor use are presently being advocated but, if this is the direction which codes are to follow, then it is preferable in this age of computer technology that a true system should be adopted rather than a simplification. A philosophically satisfactory method can readily be found which can fulfilcurrent requirements and it is better that such a method should be adopted from the beginning rather than later to find it necessary to make important alterations and amendments.

Jan 1, 1996

By John R. Davie

This paper describes the design and construction of two 5.6 MN capacity drilled piers installed to support the main loading elements of a large cantilevered gantry crane. The critical crane columns were located within and at the edge of an existing sheet-pile cofferdam, which had been filled with loose coal slag when it was originally constructed Due to the presence of the slag and the age and questionable condition of the sheet-piles, the drilled piers were installed to provide vertical and lateral supports for these columns. The lateral capacity of the piers was supplemented by two smaller drilled piers and two large spread footings that were linked by a system of grade beams.

Jan 1, 2006

By S. L. Karunakaran

There are cases where it is found that a raft foundation would have adequate factor of safety against ultimate bearing capacity failure but the settlements would be excessive. Piles may be introduced in order to limit settlements to an acceptable level. The actual number of piles required to reduce the settlements to an acceptable level may be very small compared to the number of piles required to transmit the whole structure load. The paper focuses on the difficulties encountered in evaluating the load sharing between raft and piles. An elaborate analysis taking into account the interaction between raft, piles and soil is very complex and time consuming. Few approximate methods for arriving at a satisfactory solution to piled raft system are discussed in the present paper.

Jan 1, 1996

By Raffaella Granta

Mosul Dam is an earth fill dam located on the Tigris River, approximately 40 km (25 mi) northwest of Mosul, Iraq. The construction of the dam was completed in 1984. It is one of the largest multipurpose dams in the Middle East, and the largest dam in Iraq. The dam provides flood control, irrigation, power generation and water supply. At 113 m (371 ft) high and 3.65 km (2.3 mi) long, the reservoir has a storage capacity of 11.1 billion m3 (392 billion ft3) of water. The main hydroelectric power station has four turbines for an installed capacity of 750 MW. The discharge system includes two bottom-outlet tunnels of 10 m (33 ft) diameter, a five-gate service spillway and an emergency fuse plug spillway.

Oct 1, 2022

By Subhash B. Bhide

Deep foundations are affected by the presence of sulphates, chlorides, organic contents and water currents present in the soil. The sulphates in soil and ground water interfere first with setting of concrete. In long term, growing of sulphate crystals in concrete, crevices can spall the concrete. The chlorides mainly affect the steel. The organic content does not allow the concrete to set. It also reduces the compressive strength of concrete. The frequency and methods of sampling and testing for above corrosive elements are discussed. Presently available methods to avoid attack due to these corrosive elements are discussed. The stipulations by various codes are summarised. A method to assess the short term impact is elaborated with results of field studies. A tool developed to study the presence and effects of underground water currents on concrete is also discussed.

Jan 1, 1996

By Ashley Shirer

Have you heard a geotechnical engineer rail against using the word "dirt"? The typical maxim is: "It's not dirt, it's soil!" This axiom is so prevalent that it is joked about on the construction site. How did we get to the point in our profession that soil is too technical to understand, while dirt is not viewed as important? Take a moment and think about the images that come to mind by the word soil. Responses range from the sand at a playground to the mud that sticks to the bottom of your shoe, the dark loam found in gardens to the firm earth under your feet. But do you know where the term soil originated? Or how it was intended to be used? This article looks at how word choice can lead to very different motivations for owners, designers and constructors.

May 1, 2023

By Timothy C. Siegel

Drilled displacement piles (also known as augered cast-in-place displacement piles or augured, pressure grouted displacement piles) are installed by the displacement of soil and subsequent placement of fluid cement grout within the evacuated volume. Depending on the soil grain-size characteristics, soil behavior, in situ soil density, pile spacing, and pile diameter, the installation process can result in measurable densification and an increase in lateral stress. This paper examines the conditions prior to and following the installation of drilled displacement piles at sandy sites using the cone penetration test. The data support that the installation of drilled displacement piles results in a substantial increase in tip resistance.

Jan 1, 2007

By Shamsher Prakash

Estimation of vertical load carrying capacity of a single vertical pile under earthquake loading is an important task of a design engineer. Lateral vibration of vertical pile is highly influenced by the magnitude of vertical load. Several load reversal, during earthquake loading introduce gap between pile soil interface which reduces its load carrying capacity and increases lateral motion. This paper presents a simple time domain numerical scheme to estimate the lateral pile response, considering the loss of contact of pile at pile soil interface, during impact and earthquake loading. The motion of the pile is limited in the vertical plane. Time domain has been discretised into small intervals. The non linearity of soil properties has been taken into account by discretised Winklers model with Wolfes frequency independent mass spring dash pot coefficient for geometric damping. Suitable software has been developed which keeps track of the load reversal point of each elements.

Jan 1, 1996