Simplified assessment of pile-head kinematic demand in layered soil

Stacul, Stefano; Squeglia, Nunziante

doi:10.1016/j.soildyn.2019.105975

Cited by 16 publications

(11 citation statements)

References 32 publications

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“…The results of this study extend, therefore, the validity of the simple analytical solutions to the non-linear range of soil response, denoting that kinematic soil-pile interaction is controlled by the soil stiffness even if the response of the soil is controlled by its strength. The above finding generalizes earlier indications [27][28][29][30] of the controlling role of the mobilized soil stiffness on pile kinematic bending.…”

Section: Frequency Effects: Proposed Analytical Expressionsupporting

confidence: 90%

Kinematic Pile-Head Bending Under Large Earthquake-Induced Shear Strains

Stacul¹,

Rovithis²,

Laora³

2021

Proceedings of the 8th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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The problem of kinematic bending moments imposed at the head of a single pile during the passage of seismic waves is explored under large shear strains in the surrounding soil. To this end, non-linear soil response at free-field conditions is derived numerically by a freelyavailable 1D code and then utilized to calibrate the constitutive law of soil introduced in a rigorous 3D Finite-Difference (FD) model of the soil-pile system employed to obtain pile's head bending moments. The pile is considered embedded to a normally-consolidated clay and seven earthquake records with different amplitude and frequency content are imposed as input motions at the base of the soil layer, thus allowing the investigation of pile kinematic bending with increasing levels of shear strains in the soil, exceeding the limit of equivalentlinear soil behavior. The performance of a simple analytical expression for predicting the kinematic bending moment at the pile-head is compared to the rigorous FD solution. It is concluded that this simple solution is still applicable, with slight modifications, for high shear strains related to non-linear soil behavior close to shear failure, provided that the proper mobilized soil properties from 1D soil response analysis are introduced.

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Section: Frequency Effects: Proposed Analytical Expressionsupporting

confidence: 90%

Kinematic Pile-Head Bending Under Large Earthquake-Induced Shear Strains

Stacul¹,

Rovithis²,

Laora³

2021

Proceedings of the 8th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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“…The nonlinearity of the unsaturated soil is neglected, and thus a linearly elastic soil constitution is adopted for mathematical convenience in this study. Literature research from Stacul et al 30 and Mucciacciaro and Sica 31 shows that some deviations in comparisons with the calculated results utilizing nonlinear soil constitution will occur. However, the motivation of the proposed solution is to simulate the Rayleigh wave propagation across the unsaturated soil-pile system and elastic soil constitution is sufficient enough.…”

Section: Mathematical Model and Assumptionsmentioning

confidence: 90%

“…There are two main simplifications and explanations are listed adopted in this paper as follows: The nonlinearity of the unsaturated soil is neglected, and thus a linearly elastic soil constitution is adopted for mathematical convenience in this study. Literature research from Stacul et al 30 . and Mucciacciaro and Sica 31 shows that some deviations in comparisons with the calculated results utilizing nonlinear soil constitution will occur.…”

Section: Mathematical Model and Assumptionsmentioning

confidence: 92%

Flexible support of a pile embedded in unsaturated soil under Rayleigh waves

Yang

Líu

et al. 2022

Earthq Engng Struct Dyn

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Under the action of Rayleigh waves, pile head is easy to rotate with a concrete pile cap, and pure fixed-head condition is rarely achieved, which is a common phenomenon for it usually occurs on the precast piles with insufficient anchorage. In addition, the propagation characteristics of Rayleigh wave have been changed significantly due to the existence of capillary pressure and the coupling between phases in unsaturated soil, which significantly affects the pile-soil interaction. In order to study the above problems, a coupled vibration model of unsaturated soil-pile system subjected to Rayleigh waves is established on the basis that the pile cap is equivalent to a rigid mass block. Meanwhile, the soil constitution is simplified to linear-elastic and small deformations are assumed to occur during the vibration phase of soil-pile system. Then, the horizontal dynamic response of a homogeneous free-field unsaturated soil caused by propagating Rayleigh waves is obtained by using operator decomposition theory and variable separation method. The dynamic equilibrium equation of a pile is established by using the dynamic Winkler model and the Timoshenko beam theory, and the analytical solutions of the horizontal displacement, rotation angle, bending moment and shear force of pile body are derived according to the boundary conditions of flexible constraint of pile top. Based on the present solutions, the rationality of the proposed model is verified by comparing with the previous research results. Through parametric study, the influence of rotational stiffness and yield bending moment of pile top on the horizontal dynamic characteristics of Rayleigh waves induced pile is investigated in detailed. The analysis results can be utilized for the seismic design of pile foundation under Rayleigh waves.

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“…The methods described in the literature to account for kinematic interaction effects in the seismic analysis of piles are broadly classified into numerical and analytical. Numerical methods such as the Finite Element Method [13][14][15][16][17][18][19][20] and the Boundary Element Method [21][22][23][24][25][26][27][28] have been widely used to study the response of piles affected by seismic waves, but are seldom used in engineering practice as the cost associated with performing three dimensional dynamic simulations is often prohibitive. A much more efficient alternative to modelling the pile and its surrounding soil as continua is the Beam-on-Dynamic-Winkler-Foundation (BDWF) concept, in which soil resistance to pile deformations is modelled by means of distributed and independent springs and dashpots.…”

Section: Introductionmentioning

confidence: 99%

Transverse seismic response of end‐bearing pipe piles to S‐waves

Zheng

Luo

Kouretzis

et al. 2022

Num Anal Meth Geomechanics

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This paper presents a method for the seismic analysis of open-ended pipe piles subjected to vertically propagating S-waves, that considers kinematic interaction between the pipe pile and its external and internal soil. Following the presentation of the elastodynamic continuum model, which is based on the assumptions of linear elastic soil response and uniform soil conditions, we employ the derived solution to investigate the sensitivity of the seismic response of pipe piles to certain key problem parameters, such as pile slenderness or the relative stiffness of the pipe pile compared to its surrounding soil. We demonstrate that the bending stiffness of pipe piles is governing their seismic response, and that thin-walled pipe piles offer the best material usage versus seismic performance ratio. The presented solution offers a low-cost alternative to complex numerical simulations for preliminary seismic design purposes, such as the selection of optimal pipe pile section geometry.

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Simplified assessment of pile-head kinematic demand in layered soil

Cited by 16 publications

References 32 publications

Kinematic Pile-Head Bending Under Large Earthquake-Induced Shear Strains

Kinematic Pile-Head Bending Under Large Earthquake-Induced Shear Strains

Flexible support of a pile embedded in unsaturated soil under Rayleigh waves

Transverse seismic response of end‐bearing pipe piles to S‐waves

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