A numerical procedure to correlate the subgrade reaction coefficient with soil stiffness properties for laterally loaded piles using the FSAFEM

2017 ◽  
Vol 13 (5) ◽  
pp. 458-473 ◽  
Author(s):  
Lamia Medjitna ◽  
Djillali Amar Bouzid
1984 ◽  
Vol 21 (3) ◽  
pp. 431-438 ◽  
Author(s):  
J. F. (Derick) Nixon

A theory for the design of laterally loaded piles in permafrost is presented. The approach is valid for icy soils or ice, where secondary creep displacements will be responsible for the majority of the soil strain under sustained load. Initially, the paper studies in some detail the response of a short, rigid pile embedded in a nonlinear viscous medium. The concept of a flexible elastic pile in a viscous continuum is then introduced, and a relatively straightforward numerical procedure must be introduced to obtain a solution. Once the limiting or design ground surface displacement rate is established by the designer, the paper shows how a typical chart relating lateral pile load to average ground temperature can be prepared.The available (but limited) data base is reviewed for field pile load tests carried out in the early 1970's in Inuvik, N.W.T. and some laboratory model pile tests carried out in connection with this study. Using available long-term secondary creep data for ice and icy silts, predictions for the lateral creep response of piles can be carried out. Agreement between prediction and observation is certainly encouraging and points the way to further research and field testing in this area. Finally, the paper briefly discusses the resistance of rigid fixed-headed piles to lateral loads, and the resistance of a pile in permafrost to the application of a pure moment. Key words: lateral piles, permafrost, creep, model, field tests.


1987 ◽  
Vol 24 (2) ◽  
pp. 289-296 ◽  
Author(s):  
Muniram Budhu ◽  
Trevor G. Davies

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.


Author(s):  
Matt Bristow

A new analytical method is presented to determine the effects of cyclic loading on laterally loaded piles. The method uses a new numerical procedure to quantify the effects of the cyclic loading at each soil depth and convert that to a set of cyclic p-y modifiers. The reduced foundation stiffness associated with the cyclic loading can be determined, including the residual static capacity and an estimate of the accumulated displacement. The new method introduces the concept of cyclic degradation damage, which is defined as sum of the cyclic degradation that is occurring at each soil depth. Cyclic degradation calculations are based on the shear stresses in the soil. Consequently, anything that causes the shear stresses to change (e.g. pile length, pile diameter, applied loading, etc.) will automatically be included in the calculation of cyclic p-y modifiers. The method has been validated by comparing the cyclic p-y curves produced using the new method with established cyclic p-y curves derived from fielding testing. The new method has also been used to investigate what happens to the cyclic p-y modifiers as one moves away from the reference conditions used to determine the established cyclic p-y curves in API RP2A (2000). The new method shows that every application (e.g. combination of cyclic loading, pile properties, and soil characteristics) has its own unique set of cyclic p-y curves, though most p-y curves fit within an upper and lower bound range. Examples are provided for large diameter monopiles.


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