Capacity Of Piles In Sand Research Articles

Discussion of “Determination of Bearing Capacity of Open-Ended Piles in Sand” by Kyuho Paik and Rodrigo Salgado

Discussion of “Determination of Bearing Capacity of Open-Ended Piles in Sand” by Kyuho Paik and Rodrigo Salgado

Closure to “Determination of Bearing Capacity of Open-Ended Piles in Sand” by Kyuho Paik and Rodrigo Salgado

Closure to “Determination of Bearing Capacity of Open-Ended Piles in Sand” by Kyuho Paik and Rodrigo Salgado

Interface Load Transfer Degradation During Cyclic Loading: A Microscale Investigation

The shaft capacity of piles in sand subjected to cyclic (wave) loading has been observed to decrease significantly with loading cycles (Poulos, 1989). A number of researchers (Boulon and Foray, 1986; Tabucanon et al., 1995; Shahrour et al., 1999) have replicated the characteristics of the load transfer degradation behavior in the laboratory through cyclic interface shear testing with a constant normal stiffness confinement condition (Vesic, 1972). However, no consensus currently exists as to the primary microscale mechanisms that govern cyclic interface shear behavior and load transfer degradation. A research program was undertaken to quantify the contribution of soil properties, cementation, confinement condition, and displacement mode, in load transfer degradation. Monotonic and cyclic interface shear tests were performed using a modified interface direct shear device with a Perspex side window. The specimen particle displacement fields were quantified during selected cycles by capturing high resolution digital images (1600 x 1200 pixels) and using Particle Image Velocimetry (White et al., 2001a). Results indicate that the confinement condition, which is intended to replicate the elastic response of the far-field soil, is of primary importance as it allows for normal stress relaxation with soil contraction adjacent to the interface. The displacement magnitude, particle characteristics, and particle-particle cementation were also observed to affect the magnitude and rate of degradation. It is anticipated that these findings will provide a fundamental rationale to identify field conditions where shear stress degradation is likely to occur and a basis from which more rigorous models may be developed.

Closure to “Discussion on ‘Direct Shear Interface Test for Shaft Capacity of Piles in Sand’ by K. S. Subba Rao, Mehter M. Allam, and Retnamony G. Robinson” by E. Saibaba Reddy, D. N. Chapman, and V. V. R. N. Sastry

Closure to “Discussion on ‘Direct Shear Interface Test for Shaft Capacity of Piles in Sand’ by K. S. Subba Rao, Mehter M. Allam, and Retnamony G. Robinson” by E. Saibaba Reddy, D. N. Chapman, and V. V. R. N. Sastry

Direct Shear Interface Test for Shaft Capacity of Piles in Sand

Abstract For precise estimation of shaft capacity of a pile, it is essential to determine accurately the soil-pile interface friction angle (δ). The apparatus available to measure the value of δ, the miniature pile test apparatus and the soil-pile-slip test apparatus are only available for research purposes. This paper presents the details of an investigation carried out using the conventional direct shear test apparatus to measure the value of δ for soil-pile interface. The direct shear interface tests were conducted using four types of surfaces and two types of sands. The values of δ obtained from these tests are compared with the internal friction angle (φ) of the sand and with the results obtained from soil-pile-slip tests. The interface test results are also used to estimate the shaft capacity of a few model piles embedded in sand.

Measured Time Effects for Axial Capacity of Driven Piling

The results of a study to quantify effects of time on pile capacity are presented herein. The main focus of this paper is to present results from a database developed from various pile tests reported in the literature and to present some observations based on the pile test data. Both sands and clays are shown to experience setup. A database containing 80 pile load tests (both static and dynamic) was collected and sorted into three groups according to the primary subsurface profile: sands, clays, and mixed soil. Capacity-versus-time relationships are plotted for each soil type, but particular attention is given to the increase in capacity of pile in sand with time. It is shown that the load test results can provide an upper-bound estimate and a lower-bound estimate. Estimating the effect of time on pile capacity in sand can be important for reuse of existing piling and also can be helpful for quantifying just how much to expect capacity to increase with time if pile load tests show that capacities are coming up short.

Bearing capacity of shaft-expanded driven model piles in sand

Bearing capacity of shaft-expanded driven model piles in sand

Closure to “Tensile and Compressive Shaft Capacity of Piles in Sand” by Anthony De Nicola and Mark F. Randolph

Closure to “Tensile and Compressive Shaft Capacity of Piles in Sand” by Anthony De Nicola and Mark F. Randolph

Tensile and Compressive Shaft Capacity of Piles in Sand

Tensile and Compressive Shaft Capacity of Piles in Sand

Tensile and compressive shaft capacity of piles in sand : A. de Nicola & M.F. Randolph, Journal of Geotechnical Engineering — ASCE, 119(12), 1993, pp 1952–1973

Tensile and compressive shaft capacity of piles in sand : A. de Nicola & M.F. Randolph, Journal of Geotechnical Engineering — ASCE, 119(12), 1993, pp 1952–1973

Pile capacity in sand — the critical depth myth : Randolph, M Aust GeomechN24, Aug 1993, P30–34

Pile capacity in sand — the critical depth myth : Randolph, M Aust GeomechN24, Aug 1993, P30–34

Tensile and Compressive Shaft Capacity of Piles in Sand

In most soil types, it is generally assumed that the shaft capacity of a pile is identical under both tensile and compressive loading. However, there is widespread experimental evidence that in sand the shaft capacity is significantly lower for tensile loading, or uplift, than for compressive loading. This paper describes the results of a parametric study that was conducted to explore the theoretical basis for such differences. It is shown that the primary cause of lower tensile capacity is due to a Poisson’s ratio effect, and that the ratio of tensile to compressive shaft capacity may be expressed as a function of the relative compressibility of the pile and the slenderness ratio. Design recommendations are proposed, and corroborated with results from high-quality field tests.

Discussion of “ Model for Capacity of Single Piles in Sand Using Fuzzy Sets ” by C. H. Juang, J. L. Wey, and D. J. Elton (December, 1991, Vol. 117, No. 12)

Discussion of “ <i>Model for Capacity of Single Piles in Sand Using Fuzzy Sets</i> ” by C. H. Juang, J. L. Wey, and D. J. Elton (December, 1991, Vol. 117, No. 12)

Closure to “ Model for Capacity of Single Piles in Sand Using Fuzzy Sets ” by C. H. Juang, J. L. Wey, and D. J. Elton (December, 1991, Vol. 117, No. 12)

Closure to “ <i>Model for Capacity of Single Piles in Sand Using Fuzzy Sets</i> ” by C. H. Juang, J. L. Wey, and D. J. Elton (December, 1991, Vol. 117, No. 12)

Computing axial pile capacity in sands for offshore conditions : Kraft, L M Marine GeotechnolV9, N1, Jan–March 1990, P61–92

Computing axial pile capacity in sands for offshore conditions : Kraft, L M Marine GeotechnolV9, N1, Jan–March 1990, P61–92

Computing axial pile capacity in sands for offshore conditions

Abstract The application of a new criterion to compute the axial capacity of pipe piles driven into sands is described for offshore conditions. The new criterion is tested, independently, against measured capacities from 64 pile load tests and is compared with current recommended practice of API RP2A. These comparisons show that the new criterion is more reliable than the current API criterion and that the new criterion can provide greater capacities for long, large‐diameter pipe piles used in the marine environment. Topics also discussed include (1) the use of limiting values for unit shaft resistance and unit end bearing, (2) computing the capacity of piles in layered soil profiles, (3) the soil plug resistance in overcoming end bearing resistance, and (4) the influence of rate of loading and cyclic loading on pile capacity. A few examples are included to demonstrate the applications.

Pull-out capacity of single batter piles in sand: Discussion

The interesting experiments carried out by Hanna and Afram bring to mind a series of tests conducted by the writer some 20 years ago at the Danish Geotechnical Institute (Schmidt and Kristensen 1964). A brief review of this test series supports some of the experimental findings of the authors, but a slightly different philosophy is suggested for the interpretation of the data. The writer conducted a series of more than 40 axial pull-out tests on inclined model piles for three different pile inclinations and a variety of sand densities and friction angles. The tests were carried out in a sand box similar to that used by the authors. These axial pull-out tests were the initial part of tests modeling the failure of retaining walls anchored by inclined anchor piles. This type of test puts a nonaxial load on the piles. Writing the general formula for skin friction on piles in sand as follows:

Uplift capacity of piles in sand : Chattopadhyay, B C; Pise, P J J Geotech Engng DivASCEV112, N9, Sept 1986, P888–904

Uplift capacity of piles in sand : Chattopadhyay, B C; Pise, P J J Geotech Engng DivASCEV112, N9, Sept 1986, P888–904

Uplift Capacity of Piles in Sand

An analytical method has been proposed to predict the ultimate uplift capacity of piles embedded in sand. The method takes into consideration the length, diameter, and surface characteristics of piles and the soil properties. Typical charts for evaluation of average skin friction values for piles are presented through figures in dimensionless quantities. Critical depth of embedment beyond which the average skin friction attains a constant value depends not only on the relative density of sand but significantly on pile surface characteristics. Reasonable agreement has been observed between the measured and predicted values of uplift capacities. Among the available methods the proposed analysis predicts more realistic values of uplift capacities.

Scale Effects of Ultimate Pile Capacity

Methods of estimating the ultimate bearing capacity of piles in sand from the results of static cone and standard penetration tests are compared with the results of load tests on driven and bored piles of different sizes and embedment ratios in the sand bearing stratum. An empirical reduction factor of the ultimate unit point resistance in sand is established, which decreases with greater pile base diameter and with greater average static cone or standard penetration resistance near the pile point. Similarly, for piles in stiff fissured clay an empirical reduction factor of the undrained shear strength is established, which decreases with greater pile base diameter and is greater for driven than for bored piles. The ultimate unit skin friction of piles in a given sand or clay is practically independent of the pile diameter.