Numerical Implementation of a 3-D Nonlinear Seismic S-P-S-I Methodology
01 Jan 1997-pp 96-110
About: The article was published on 1997-01-01 and is currently open access. It has received 5 citations till now. The article focuses on the topics: Soil structure interaction.
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TL;DR: In this paper, a continuum model for the interaction analysis of a fully coupled soil-pile-structure system under seismic excitation is presented, and the acceleration of the piled-structures at ground level can, in general, be larger than that of free-field shaking of the soil site, depending on the excitation frequency.
Abstract: A continuum model for the interaction analysis of a fully coupled soil–pile–structure system under seismic excitation is presented in this paper. Only horizontal shaking induced by harmonic SH waves is considered so that the soil–pile–structure system is under anti-plane deformation. The soil mass, pile and superstructure were all considered as elastic with hysteretic damping, while geometrically both pile and structures were simplified as a beam model. Buildings of various heights in Hong Kong designed to resist wind load were analysed using the present model. It was discovered that the acceleration of the piled-structures at ground level can, in general, be larger than that of a free-field shaking of the soil site, depending on the excitation frequency. For typical piled-structures in Hong Kong, the amplification factor of shaking at the ground level does not show simple trends with the number of storeys of the superstructure, the thickness and the stiffness of soil, and the stiffness of the superstructure if number of storeys is fixed. The effect of pile stiffness on the amplification factor of shaking is, however, insignificant. Thus, simply increasing the pile size or the superstructure stiffness does not necessarily improve the seismic resistance of the soil–pile–structure system; on the contrary, it may lead to excessive amplification of shaking for the whole system. Copyright © 2003 John Wiley & Sons, Ltd.
24 citations
20 Aug 2011
TL;DR: In this article, the authors developed modified p-y curves for Winkler analysis to characterize the lateral load behavior of a single pile embedded in a volume of improved clay surrounded by unimproved soft clays.
Abstract: In the past decades, the behavior of pile foundations in liquefiable sands has been studied extensively; however, similar investigations of soft clays or static/seismic response of piles in improved soft clay soils are scarce. Despite the widespread presence of this soil type in high seismic regions and the frequent need to locate bridges and buildings in soft clay, only a few investigations have been carried out to guide engineers in evaluating the effectiveness of ground improvement techniques on increasing the lateral resistance of pile foundation embedded in soft clay, and no numerical models have been validated to evaluate this approach. Thus, the objective of this research was to develop modified p-y curves for Winkler analysis to characterize the lateral load behavior of a single pile embedded in a volume of improved clay surrounded by unimproved soft clays. A detailed literature review was completed in the study, aiming to gain knowledge on the development and fields of applications together with limitations of different ground improvement techniques. The ability of each available analysis method for lateral loaded piles was assessed for determining lateral responses of pile foundation in a volume of improved soil surrounded by unimproved soil. A method of developing p-y curve modification factors to account for the effect of the improved soil on enhancing the lateral load behavior of a single pile embedded in soft clay was developed by integrating the effectiveness of the improved soil into the procedures of constructing p-y curves for stiff clay recommended by Welch and Reese (1972). It was achieved by estimating the effective length for a infinitely long soil layer with soil improvement so that the fraction of the load resisted by the soil improved over a
13 citations
Cites background from "Numerical Implementation of a 3-D N..."
...Cai et al. (1995) analyzed a three-dimensional nonlinear finite element subsystem model consisting of substructured solutions of the superstructure and soil-pile systems....
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...Davisson and Gill (1963) investigated the case of a laterally loaded pile embedded in a layered soil system with a constant (but different) modulus of subgrade reaction for each layer, but it was varied between layers....
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01 Jun 2010
TL;DR: In this paper, the authors proposed a 2.40G dataset, where 40G is the total amount of data generated by all the users in the dataset and 3.4G is their download rate.
Abstract: 40G場の遠心模型実験により，均一で密な砂地盤で下端支持杭を持つ2自由度構造物の動的応答について調べる。上部工の慣性力が杭基礎に与える影響を考察するため上部工の有無，入力正弦波の振幅と振動数を変化させて実験を行う。また，実験結果を2次元非線形動的有限要素解析結果と比較する。ただし，本質的に3次元の問題である杭?地盤の動的相互作用は，応力履歴を考慮できる地盤?杭相互作用ばねを導入し2次元でモデル化するものとする。加速度および変位時刻歴については実験と解析とで良い一致を示したが，曲げモーメントについては今後の検討が必要である。
5 citations
TL;DR: In this paper, the nonlinear response of coupled soil-pile-structure systems to seismic loading is parametrically studied in the frequency domain using two-dimensional (2D) finite elements.
Abstract: The non-linear response of coupled soil-pile-structure systems to seismic loading is parametrically studied in the frequency domain using two-dimensional (2D) finite elements (FE). The soil-pile interaction in three dimensions (3D) is idealized in the 2D type using soil-pile interaction springs with non-linear hysteretic load displacement relationships. The system under investigation comprises of a single degree of freedom structure supported by an end-bearing single pile founded in a homogenous sand layer over rigid rock. Comparisons with established results from the literature suggest that the adopted FE model reasonably captures the essential features of the seismic response of the coupled soil-pile-structure system. Numerical results demonstrate the strong influence on the effective natural period of the foundation properties. The effect of non-linear soil behavior and soil profile as well as the frequency content of excitation on both kinematic and inertial interactions is illustrated. The relative contributions of kinematic and inertial interaction to the development of dynamic pile bending are clarified.
2 citations
31 Aug 2012
TL;DR: In this paper, the interaction between adjacent buildings with different foundation levels under earthquakeloading conditions is studied using axisymmetric fein element method in corporation of grob element for soil region and wave input technique transit boundary condition.
Abstract: The aim of this paper is to study the interaction between adjacent buildings with different foundation levels under earthquakeloading conditions. Buildings and soil are represented by two different models. In the first case the building itself is modeled withstandard frame element, whereas the soil behavior is stimulated by a special grid model. In the second case, the building and soilare represented by plane stress or plane strain elements. The modulus of elasticity of the ground is varied. Just like the modi-fication of the modulus of elasticity the varying relations of inertia have a strong influence on the section forces within the build-ings. The analysis is carried out using numerical program which has been developed based on the axisymmetric fein elementmethod in corporation of grob element for soil region and wave input technique transit boundary condition. Interaction of the pro-posed method is demonstrated in numerical examples.Key words : Soil-structure interaction, Grid model, Wave input technique, Earthquake response