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 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 Pile lateral subgrade reaction modulus for Jakarta

2019 ◽  
Vol 270 ◽  
pp. 02002
Author(s):  
Saskia Nadilla ◽  
Widjojo Adi Prakoso
Keyword(s):  
Load Cycle ◽  
Reaction Model ◽  
Lateral Loads ◽  
Subgrade Reaction ◽  
Lateral Deflection ◽  
Linear Elastic ◽  
Construction Methods ◽  
Cyclic Lateral Load ◽  
Load Tests ◽  
Laterally Loaded

The behavior of laterally loaded piles could be simulated by the subgrade reaction model. The primary soil parameter for this model is the subgrade reaction modulus, and in this paper, the correlation between the subgrade reaction modulus and the soil N-SPT value is examined by conducting numerical analyses of 34 pile cyclic lateral load tests in Jakarta. In each analysis, the pile is modeled as a series of beam elements, while the surrounding soil is modeled as a series of linear elastic springs. The moduli are varied according to the N-SPT values recorded in the associated deep boring data. In each load cycle, a trial and error process is conducted to match the resulting pile head lateral deflection to the measured value. The resulting correlation between the subgrade reaction modulus and the pile lateral deflection is presented for the 34 case studies and compared to a correlation in the literature. Furthermore, the analyses reveal that subgrade reaction modulus is affected by the magnitude of measured deflection, by the applied lateral loads, as well as by the construction methods.

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.

Slip modulus in bolted timber joints

1992 ◽  
Vol 19 (6) ◽  
pp. 960-964 ◽  
Author(s):  
D. B. Van Dyer
Keyword(s):  
Test Results ◽  
Lateral Loads ◽  
Initial Load ◽  
Theoretical Predictions ◽  
Mechanically Fastened ◽  
Timber Joints ◽  
Interlayer Slip ◽  
Laterally Loaded ◽  
Wood Columns ◽  
Good Agreement

This paper is concerned with the initial load–slip behaviour of laterally loaded bolted timber joints and deals specifically with verifying a theory for determining the values of slip modulus in mechanically fastened timber joints. Such a theory is essential in dealing with the phenomenon of interlayer slip, which occurs in built-up timber columns with nonrigid joints. The concept of a beam on an elastic foundation is used to evaluate the slip modulus. The theoretical predictions are compared with the test results of 75 timber joints. Good agreement is observed between the experiment and the theory. Key words: timber joints, bolts, nails, wood, interlayer slip, slip modulus, built-up wood columns, shear, lateral loads.

scholarly journals Settlement of a Pile under Cyclic Lateral Loads in Dry Sand

Géotechnique ◽  
2021 ◽  
pp. 1-32
Author(s):  
Gang Zheng ◽  
Jibin Sun ◽  
Tianqi Zhang ◽  
Yu Diao
Keyword(s):  
Theoretical Model ◽  
Load Transfer ◽  
Lateral Loads ◽  
Cyclic Lateral Load ◽  
Practical Engineering ◽  
Pile Settlement ◽  
Dry Sand ◽  
Transfer Method ◽  
Laterally Loaded ◽  
Load Transfer Method

It is found through centrifuge model tests that the cyclic lateral load on a pile reduces the shaft friction and induces additional pile settlement. A theoretical model using the load-transfer method was proposed for the settlement prediction of cyclic laterally loaded piles in dry sand. A simple formula was established to quickly predict the pile settlement in practical engineering. The theoretical model provided a reasonable estimate of the pile settlement, while the predictions from the proposed quick prediction formula were relatively conservative. A new concept of “settlement-controlled design” was proposed to advance the methodology for the design of a pile by considering potential settlement after many cycles of lateral loads. According to the design plane derived from this study, the design-state points were suggested to be limited in the convergent zone.

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.

scholarly journals Influence of Vertical Loading on Behavior of Laterally Loaded Foundation Piles: A Review

2020 ◽  
Vol 8 (12) ◽  
pp. 1029
Author(s):  
Qiang Li ◽  
Luke J. Prendergast ◽  
Amin Askarinejad ◽  
Ken Gavin
Keyword(s):  
Large Diameter ◽  
Offshore Wind ◽  
Pile Foundations ◽  
Future Research ◽  
Gravitational Acceleration ◽  
Lateral Loads ◽  
Vertical Loading ◽  
Lateral Response ◽  
Current Design ◽  
Laterally Loaded

The majority of installed offshore wind turbines are supported on large-diameter, open-ended steel pile foundations, known as monopiles. These piles are subjected to vertical and lateral loads while in service. In current design practice, interaction of vertical and lateral loads are not considered, rather piles are designed to resist vertical and lateral loads independently. Whilst interaction effects are widely studied for shallow foundations, the limited research on this topic for pile foundations often produces conflicting results. This paper reviews the research of the influence of vertical loading on the lateral response of pile foundations under combined loads, from the perspective of analytical research, numerical research, and experimental research from tests performed on 1-g (gravitational acceleration) model, centrifuge, and full-scale piles. The potential reasons for the differences among the results of previous research are discussed. Some guidance for future research on the effect of vertical loads on the lateral response of piles is provided.

scholarly journals A Full 3-D Finite Element Analysis of Group Interaction Effect on Laterally Loaded Piles

2018 ◽  
Vol 12 (5) ◽  
pp. 9
Author(s):  
Amer Alkloub ◽  
Rabab Allouzi ◽  
Haider Alkloub ◽  
Ramia Al-Ajarmeh
Keyword(s):  
Finite Element ◽  
Interaction Effect ◽  
Group Interaction ◽  
Reduction Factor ◽  
Lateral Loads ◽  
Laterally Loaded Piles ◽  
Element Analysis ◽  
Pile Diameter ◽  
Lateral Resistance ◽  
Laterally Loaded

Piles are used for many types of structures to resist vertical and lateral loads.  Design considerations of piles under lateral load are very crucial because the lateral performance of the pile foundations significantly influences the integrity of the structures supported by group of piles.  Finite element study has been conducted to investigate the group interaction effect on the laterally loaded piles.  This study investigates three factors, piles spacing, group arrangement, and group size.  It has been concluded that: (1) As the piles spacing increases as the reduction factor increases and becomes close to one. (2) No reduction due to group interaction for piles spaced at eight times the pile diameter. (3) Group efficiency factor increases in piles that are arranged in a single row. (4) As the number of piles increases more reduction in the lateral resistance occurs.

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