Dynamic Behaviour Of Pile Foundations Research Articles

Correction to: A probabilistic investigation on the dynamic behaviour of pile foundations in homogeneous soils

Correction to: A probabilistic investigation on the dynamic behaviour of pile foundations in homogeneous soils

A probabilistic investigation on the dynamic behaviour of pile foundations in homogeneous soils

A probabilistic investigation on the dynamic behaviour of pile foundations in homogeneous soils

Dynamic behavior of pile foundations under vertical and lateral vibrations: review of existing codes and manuals

ABSTRACT Designing structures subjected to dynamic loads is quite complex and involve structural, mechanical, geotechnical engineering and the theory of vibration. Machines, buildings under seismic effect, and wind turbines induce both dynamic and static loads on their foundations. If these structures are supported on piles, a full understanding is required of the dynamic interaction between individual piles and soil (pile-soil interaction) and between adjacent piles (pile-soil-pile interaction). Due to the complexity of this problem, codes and manuals recommend the use of approximate approaches. However, there is a general lack in research concerning the accuracy of these approaches. The present paper aims to help filling this gap by comparing the recommendations from selected codes and manuals with the results obtained from the numerical analysis. The codes and manuals considered in this paper are the Egyptian Code (EC), ACI, and the Canadian Manual (CM). This comparison is held over a range of parameters including excitation force frequency (f), soil modulus of elasticity (Es), pile slenderness Ratio (L/D), dimensionless spacing ratio (S/D) and pile group size (ng). At the end of this study, advantageous and downfalls of these approaches are discussed.

Dynamic behavior of pile foundations under vertical and lateral vibrations

ABSTRACTPile foundations supporting machines, buildings under seismic effect, and wind turbines are subjected to dynamic loads. Under such conditions, there is a necessity to evaluate the dynamic behavior of piles. Therefore, a 3D numerical modeling technique is needed to consider the complicated dynamic interaction between the piles and soil (pile-soil interaction) and between adjacent piles in the same group (pile-soil-pile interaction). To validate the results of 3D numerical simulation of piles, the results obtained from the numerical model has been compared to the measurements of a selected case study. The 3D finite element model has also been used to evaluate the impedance parameters and induced peak displacements. The study is performed for single piles and pile groups. The different techniques to model the piles are evaluated. In addition, the effect of related parameters, such as excitation force frequency (f), soil modulus of elasticity (Es), pile slenderness Ratio (L/D), dimensionless spacing ratio (S/D) and pile group size (ng) have been studied.

Dynamic behavior of pile foundations under cyclic loading in liquefiable soils

In this paper, a fully coupled three-dimensional dynamic analysis is carried out to investigate the dynamic behavior of pile foundations in liquefied ground. A critical state bounding surface plasticity model is used to model soil skeleton, while a fully coupled ( u– P) formulation is employed to analyze soil displacements and pore water pressures. Furthermore, in this study, variation of permeability coefficient during liquefaction is taken into account; the permeability coefficient is related to excess pore water pressure ratio. Results of a centrifuge test on pile foundations are used to demonstrate the capability of the model for reliable analysis of piles under dynamic loading. Then, the verified model is used for a parametric study. The parametric study is carried out by varying pile length, frequency of input motion, fixity of the pile head, thickness of the liquefying soil layer and relative density of liquefying soil layer. Three different soil profiles have been considered in this study. In general, parametric studies demonstrate that fixity of the pile head, thickness of liquefying soil layer and frequency of input motion are the most critical parameters which considerably affect piles performance in liquefied grounds.

Nonlinear Dynamic Behavior of Pile Foundations: Effects of Separation at the Soil-Pile Interface

During strong ground motion, pile foundations are subjected to two special effects. First, behavior of the soil surrounding the piles is nonlinear. Second, large inertial forces are generated in the soil around the pile heads, causing separation between the soil and pile. In this paper, a new approach is presented to overcome material nonlinearity of the soil as well as geometrical nonlinearity arising due to separation. The analysis is performed in two steps. To account for material nonlinearity, equivalent linearization is used in conjunction with a hyperbolic model of the soil. The hyperbolic model defines the nonlinear stress-strain relationship of the soil. To deal with separation, a Winkler soil model is used. The dynamic stiffness reproduced by the soil model is changed according to the degree of separation. Depending on the level of excitation, different cases of separation arise which are investigated with skeleton curves. It has been found that due to separation, dynamic response of the soil-pile system increases whereas the dynamic stiffness decreases significantly.

Discussion: Dynamic behaviour of pile foundations in layered soil medium using cone frustums

Discussion: Dynamic behaviour of pile foundations in layered soil medium using cone frustums

Calibration of dynamic analysis methods from field test data

In view of the heterogeneity of natural soil deposits and approximations made in analysis methods, in situ methods of determining soil parameters are highly desirable. The problem of interest here is the nonlinear dynamic behavior of pile foundations. It is shown in this paper that soil parameters needed for simplified dynamic analysis of a single pile may be back-calculated from the dynamic response of the pile measured in the field. A pile was excited by applying a large horizontal dynamic force at the pile-head level, and the response measured. In this paper, two different (simplified) methods of modeling the dynamic response of the pile are considered. One of the methods is based on the Winkler foundation approach, with the spring constant characterized by the so-called nonlinear p– y springs. The second method is based on the equivalent-linear finite element approach, with the nonlinearity of shear modulus and damping accounted for by employing the so-called degradation relationships. In the latter, the effect of interface nonlinearity is also considered. Starting with best estimates of soil parameters, the experimental data on the response of pile is used to fine-tune the values of the parameters, and thereby, to estimate parameters that are representative of in situ soil conditions.

Dynamic behaviour of pile foundations in layered soil medium using cone frustums

An analytical method using a cone model is developed to evaluate the impedance functions of pile foundations in a layered soil medium. The dynamic behaviour of piles depends on the nature of the interaction between the piles and the surrounding soil. The soil–pile interaction effect modifies the stiffness of the piles and generates damping through energy radiation to infinity. This modified complex stiffness is called the impedance function. A physical model called a cone frustum is developed to represent the layered soil medium. It is capable of incorporating the complexity of layered soil media and the complicated behaviour of propagating waves. The analytical tool is developed based on wave propagation principles.

Dynamic behaviour of pile foundations in layered soil medium using cone frustums

An analytical method using a cone model is developed to evaluate the impedance functions of pile foundations in a layered soil medium. The dynamic behaviour of piles depends on the nature of the interaction between the piles and the surrounding soil. The soil–pile interaction effect modifies the stiffness of the piles and generates damping through energy radiation to infinity. This modified complex stiffness is called the impedance function. A physical model called a cone frustum is developed to represent the layered soil medium. It is capable of incorporating the complexity of layered soil media and the complicated behaviour of propagating waves. The analytical tool is developed based on wave propagation principles.

Dynamic behaviour of pile foundations in homogeneous and non-homogeneous media : K. Miura, A. M. Kaynia, K. Masuda, E. Kitamura & Y. Seto, Earthquake Engineering & Structural Dynamics, 23(2), 1994, pp 183–192

Dynamic behaviour of pile foundations in homogeneous and non-homogeneous media : K. Miura, A. M. Kaynia, K. Masuda, E. Kitamura & Y. Seto, Earthquake Engineering & Structural Dynamics, 23(2), 1994, pp 183–192

Dynamic behaviour of pile foundations in homogeneous and non‐homogeneous media

AbstractA three‐dimensional formulation based on Green's functions of cylindrical loads in layered semi‐infinite media is employed to investigate the dynamic behaviour of piles in homogeneous and non‐homogeneous half spaces. The pile‐soil‐pile interaction taking place in pile groups is incorporated in the model. The results presented in this paper include the dynamic stiffnesses and dampings of single piles as well as those of representative 2 × 2 and 4 × 4 square pile groups in the soil media considered in this study. In addition, the distribution of forces applied on the pile cap among the individual piles in a group is investigated.

Static and dynamic behaviour of pile foundations : Proc Ninth Southeast Asian Geotechnical Conference, Bangkok, 7–11 December 1987 V2, P6.265–6.276. Publ Bangkok: Southeast Asian Geotechnical Society, 1987

Static and dynamic behaviour of pile foundations : Proc Ninth Southeast Asian Geotechnical Conference, Bangkok, 7–11 December 1987 V2, P6.265–6.276. Publ Bangkok: Southeast Asian Geotechnical Society, 1987

Effects of soil liquefaction on dynamic behaviour of pile foundations : Hakuno, M; Iwasaki, T; Tatsuoka, F Proc Specialty Session 10, 9th International Conference on Soil Mechanics and Foundation Engineering, Tokyo, July 1977, P165–174. Publ Tokyo: Japanese Assoc for Steel Pipe Piles, 1977

Effects of soil liquefaction on dynamic behaviour of pile foundations : Hakuno, M; Iwasaki, T; Tatsuoka, F Proc Specialty Session 10, 9th International Conference on Soil Mechanics and Foundation Engineering, Tokyo, July 1977, P165–174. Publ Tokyo: Japanese Assoc for Steel Pipe Piles, 1977