Centrifugal testing of laterally loaded piles in sand

1992 ◽  
Vol 29 (2) ◽  
pp. 208-216 ◽  
Author(s):  
M. Georgiadis ◽  
C. Anagnostopoulos ◽  
S. Saflekou
Keyword(s):  
Bending Moment ◽  
Cohesionless Soil ◽  
Soil Reaction ◽  
Lateral Loads ◽  
Laterally Loaded Piles ◽  
Nonlinear Springs ◽  
Different Types ◽  
Different Diameters ◽  
Laterally Loaded ◽  
Pile Length

Results of an investigation of the response of piles in sand, under lateral loads, are presented. Model piles of three different diameters and flexural stiffnesses were tested in a centrifuge apparatus to determine prototype pile behavior. The experimental results, consisting of pile head displacements and bending moment distributions along the pile length, were interpreted, analyzed, and compared with the results of several numerical analyses. The piles were treated as elastic beams on nonlinear springs, examining several different types of soil reaction relationship (p-y curves). A new p-y relationship was developed for piles in cohesionless soil which provided very satisfactory results. Key words : pile, sand, lateral loading, centrifuge, numerical analysis.

scholarly journals An Investigation into the Effect of Cracking on the Response of Drilled and Postgrouted Concrete Pipe Pile under Lateral Loading

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Zhijun Yang ◽  
Qing Fang ◽  
Bu Lv ◽  
Can Mei ◽  
Xudong Fu
Keyword(s):  
Flexural Rigidity ◽  
Bending Moment ◽  
Test Results ◽  
Lateral Loads ◽  
Analysis Method ◽  
Pile Head ◽  
Laterally Loaded Piles ◽  
Pipe Pile ◽  
Concrete Pipe ◽  
Laterally Loaded

The cracks are likely to initiate on a lateral loaded pile and would cause greater deflection at the pile head. However, there is a lack of thorough investigation into the effect of cracking on the response of the lateral loaded pile. In this article, a full-scale field test was carried out to investigate the behavior of Drilled and Postgrouted Concrete Pipe Pile under lateral loads. A novel analysis method for the lateral loaded pile, which can take the cracking effects into consideration, was proposed, and the validity was verified by the test results. With the proposed method, the cracking effects on flexural rigidity, displacement, rotation, and bending moment of the pile were studied. In brief, cracking effect would dramatically reduce the flexural rigidity of the pile, remarkable increase the displacement and rotation of the pile top, and slightly decrease bending moment of the pile. Unambiguously, the results show that the proposed method can excellently predict the response of laterally loaded piles under cracking effects.

scholarly journals Experimental observation on laterally loaded pile in unsaturated silty soil

2019 ◽  
Vol 56 (11) ◽  
pp. 1545-1556 ◽  
Author(s):  
L.M. Lalicata ◽  
A. Desideri ◽  
F. Casini ◽  
L. Thorel
Keyword(s):  
Water Table ◽  
Ground Surface ◽  
Bending Moment ◽  
Data Interpretation ◽  
Partial Saturation ◽  
Laterally Loaded Piles ◽  
Silty Soil ◽  
Centrifuge Tests ◽  
Surface Data ◽  
Laterally Loaded

An experimental study was carried out to investigate the effects of soil partial saturation on the behaviour of laterally loaded piles. The proposed study was conducted by means of centrifuge tests at 100g, where a single vertical pile was subjected to a combination of static horizontal load and bending moment. The study was conducted on a silty soil characterized with laboratory testing under saturated and unsaturated conditions. During flight, two different positions of water table were explored. The influence of density was investigated by compacting the sample with two different void ratios. Finally, the effects of a variation of saturation degree on the pile response under loading were studied by raising the water table to the ground surface. Data interpretation allows drawing different considerations on the effects of partial saturation on the behaviour of laterally loaded piles. As expected, compared to saturated soils, partial saturation always leads to a stiffer and resistant response of the system. However, the depth of the maximum bending moment is related to the position of the water table and the bounding effects induced by partial saturation appear to be more important for loose soils.

scholarly journals Numerical Study of Laterally Loaded Piles in Soft Clay Overlying Dense Sand

2021 ◽  
Vol 7 (4) ◽  
pp. 730-746
Author(s):  
Amanpreet Kaur ◽  
Harvinder Singh ◽  
J. N. Jha
Keyword(s):  
Layer Thickness ◽  
Soft Clay ◽  
Bending Moment ◽  
Layered Soil ◽  
Clay Layer ◽  
Pile Groups ◽  
Dense Sand ◽  
Lateral Capacity ◽  
Laterally Loaded ◽  
Pile Length

This paper presents the results of three dimensional finite element analysis of laterally loaded pile groups of configuration 1×1, 2×1 and 3×1, embedded in two-layered soil consisting of soft clay at liquid limit overlying dense sand using Plaxis 3D. Effects of variation in pile length (L) and clay layer thickness (h) on lateral capacity and bending moment profile of pile foundations were evaluated by employing different values of pile length to diameter ratio (L/D) and ratio of clay layer thickness to pile length (h/L) in the analysis. Obtained results indicated that the lateral capacity reduces non-linearly with increase in clay layer thickness. Larger decrease was observed in group piles. A non-dimensional parameter Fx ratio was defined to compare lateral capacity in layered soil to that in dense sand, for which a generalized expression was derived in terms of h/L ratio and number of piles in a group. Group effect on lateral resistance and maximum bending moment was observed to become insignificant for clay layer thickness exceeding 40% of pile length. For a fixed value of clay layer thickness, lateral capacity and bending moment in a single pile increased significantly with increase in pile length only up to an optimum embedment depth in sand layer which was found to be equal to three times pile diameter and 0.21 times pile length for pile with L/D 15. Scale effect on lateral capacity has also been studied and discussed. Doi: 10.28991/cej-2021-03091686 Full Text: PDF

Response of tapered piles subjected to lateral loading

1999 ◽  
Vol 36 (1) ◽  
pp. 52-71 ◽  
Author(s):  
M Hesham El Naggar ◽  
Jin Qi Wei
Keyword(s):  
Large Scale ◽  
Bending Moment ◽  
Average Diameter ◽  
Confining Pressure ◽  
Lateral Loading ◽  
Cohesionless Soil ◽  
Lateral Loads ◽  
Moment Functions ◽  
Measured Strain ◽  
Displacement Transducers

Eighteen lateral loading tests were conducted on large-scale steel piles to establish the lateral behaviour of tapered piles in cohesionless soil. Three piles 1.52 m in length with different taper angles but the same average embedded diameter of 168 mm were installed in sand enclosed in a steel chamber 1.5 m in diameter and 1.445 m in depth. The soil chamber was lined with an air bladder so that sand inside the chamber could be pressurized to vary the confining pressure. The piles were instrumented with electrical resistance strain gauges and the horizontal pile movements at grade and the loading point were measured with displacement transducers. The bending-moment functions along the pile were calculated from the strain measurements by curve fitting the measured strain data. The soil resistance (p) and pile displacement (y) relationships were developed in the form of p-y curves by differentiating and integrating these bending-moment functions. It was found that tapered piles carried up to 77% more lateral loads than straight-sided-wall piles with the same average diameter. The maximum bending moment occurred in all piles at almost the same depth of one third of the embedded length of the pile. Hence, the cross section of tapered piles at the location of maximum bending moment was larger than that of straight-sided-wall piles, resulting in lower stresses in the pile. It was concluded that the tapered piles represent a more efficient distribution of the pile material and display better performance under lateral loading conditions.Key words: tapered piles, lateral response, p-y curves, modulus of subgrade reaction.

An Automated Approach for Designing Monopiles Subjected to Lateral Loads

2017 ◽  
Author(s):  
James P. Doherty ◽  
Barry M. Lehane
Keyword(s):  
Limit State ◽  
Ultimate Limit State ◽  
Lateral Loads ◽  
Limit States ◽  
Laterally Loaded Piles ◽  
Improve Design ◽  
Design Procedures ◽  
Automated Algorithm ◽  
Laterally Loaded ◽  
Ultimate Limit

This paper describes an automated algorithm for determining the length and diameter of monopile foundations subject to lateral loads with the aim of minimising the pile weight, whilst satisfying both ultimate and serviceability limit states. The algorithm works by wrapping an optimisation routine around a finite element p - y model for laterally loaded piles. The objective function is expressed as a function representing the pile volume, while the ultimate limit state and serviceability limit states are expressed as optimisation constraints. The approach was found to be accurate and near instantaneous when compared to manual design procedures and may improve design outcomes and reduce design time and costs.

Laterally loaded piles in sand: slope effect on P-Y reaction curves

1998 ◽  
Vol 35 (3) ◽  
pp. 433-441 ◽  
Author(s):  
S Mezazigh ◽  
D Levacher
Keyword(s):  
Preparation Method ◽  
Slope Angle ◽  
Back Analysis ◽  
Bending Moment ◽  
Laterally Loaded Piles ◽  
Quintic Spline ◽  
Centrifuge Tests ◽  
Extensive Program ◽  
Laterally Loaded ◽  
Method Model

An extensive program of centrifuge tests was undertaken to study the effect of slopes on P-Y curves in dry sand. The paper concerns the method developed in a previous series of centrifuge tests to experimentally determine P-Y curves. Bending-moment curves are fitted by local quintic spline functions through a crossed validation method and then differentiated twice. These experimental P-Y curves are validated by back analysis. The program of tests on piles near slopes is given. It includes studies of the effect of distance to the slope, slope angle, and soil properties. Sample preparation method, model piles, and the lateral-loading device are described. Deflection versus load curves, bending-moment curves, and derived P-Y curves for piles close to slopes are compared to horizontal-ground response. The coefficients that can apply to the P-Y reaction curves of the reference piles (a single pile in horizontal ground) are proposed for use in practice.Key words: pile, slope effets, models, centrifuge, bending moment, P-Y reaction curves.

Effect of Relative Density on P-Y Backbone Curves for Cyclic Lateral Load on Pile Foundations in Sandy Soil

2014 ◽  
Author(s):  
Sung-Ha Baek ◽  
Joon-Young Kim ◽  
Seung-Hwan Lee ◽  
Choong-Ki Chung
Keyword(s):  
Relative Density ◽  
Sandy Soil ◽  
Sandy Soils ◽  
Pile Foundations ◽  
Test Results ◽  
Lateral Loads ◽  
Laterally Loaded Piles ◽  
Cyclic Lateral Load ◽  
Subgrade Modulus ◽  
Laterally Loaded

Pile foundations installed to support offshore structures are primarily subjected to cyclic lateral loads due to wind, and waves. The p-y curve method, which represents a nonlinear relation between soil-pile reaction and lateral pile deflection, has been used to design cyclic laterally loaded piles. Recommended by the American Petroleum Institute (API) [10] and generally adopted to evaluate the behavior of static and cyclic laterally loaded piles installed in sandy soils, the API p-y curve contains a reduction factor for the initial horizontal subgrade modulus in order to take cyclic effects into consideration. When pile foundations are subjected to cyclic lateral loads, however, the initial horizontal subgrade modulus can both decrease and increase according to the relative density of the soil. In this paper, a series of cyclic lateral load model tests were performed on a preinstalled aluminum flexible pile to examine its cyclic lateral response under different relative density conditions. Model piles were embedded in sandy soils with relative densities of 40%, 70%, and 90% and were subjected to static as well as cyclic lateral loads. From the test results, cyclic p-y backbone curves were derived and compared with static p-y curves in identical soil conditions. Test results showed that the initial horizontal subgrade modulus increased for the model pile installed in sandy soil of 40% relative density, while decreased in relative densities of 70% and 90%. In addition, the infinite depth, above which cyclic lateral loads were supported, was evaluated and the test results were compared with the API p-y curve.

scholarly journals Effect of Eccentricity in Sandy Slope of Laterally Loaded Single Pile

2019 ◽  
Vol 15 (2) ◽  
pp. 92-100
Author(s):  
S.V. Sivapriya ◽  
R. Balamurukan ◽  
A. Jai Vigneshwar ◽  
N. Prathibha Devi ◽  
A. Shrinidhi
Keyword(s):  
Experimental Study ◽  
Bending Moment ◽  
Cohesionless Soil ◽  
Single Pile ◽  
Sloping Ground ◽  
Lateral Capacity ◽  
Governing Factor ◽  
Sandy Slope ◽  
Ground Condition ◽  
Laterally Loaded

AbstractAn experimental study was proposed to understand the behaviour of single pile in sloping ground with various eccentricity. Cohesionless soil was used for conducting experiments with a horizontal ground and with a slope of 1V:2H. With calculated stiffness factor (T) as 92 mm, the eccentricity was varied as 0T, 0.5T and 1T. The lateral capacity of the pile in horizontal and sloping ground condition decreases with increase in eccentricity; the increase in lateral capacity was linear too. The bending moment increases with increase in load; but the depth of maximum bending moment was 0.15 m for 0T and 0.5T of eccentricity. For 1T of eccentricity, the depth of maximum bending moment varied to 0.07 m from the point of load. An equation was proposed to calculate the maximum bending moment of the pile for any eccentricity for a slope of 1V:2H, which is the governing factor for pile designing.

Nonlinear analysis of laterality loaded piles in cohesionless soils

1987 ◽  
Vol 24 (2) ◽  
pp. 289-296 ◽  
Author(s):  
Muniram Budhu ◽  
Trevor G. Davies
Keyword(s):  
Lateral Loads ◽  
Cohesionless Soils ◽  
Laterally Loaded Piles ◽  
Soil Stiffness ◽  
Angle Of Internal Friction ◽  
Routine Design ◽  
Lateral Displacements ◽  
Laterally Loaded ◽  
Theoretical Results ◽  
Good Agreement

The results of a numerical analysis of single laterally loaded piles embedded in cohesionless soils, taking soil yielding into account, are presented. The analysis is intended to serve as an independent alternative to the well-known p–y method. The input parameters for the soil are the angle of internal friction and a parameter characterizing the increase in soil stiffness with depth, here assumed to be linear. A parametric study shows that soil yielding significantly increases the maximum pile bending moments and lateral displacements. Equations suitable for routine design applications are presented and the ease with which these can be applied in practice is demonstrated by an illustrative example. Good agreement between the theoretical results and data from published case histories attests to the validity of the method. Key words: analysis, angle of friction, cohesionless, deformation, design, failure, foundations, piles, lateral, loads.

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