Numerical Analysis of Seismic Response of a Piled Raft Foundation System

Varghese, Ramon; Boominathan, A.; Banerjee, Subhadeep

doi:10.1007/978-981-13-0562-7_25

Cited by 3 publications

(1 citation statement)

References 4 publications

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“…Nakai et al [2004] suggested that simplifying pile as beam elements underestimates impedance functions and over estimates Foundation Input Motions (FIMs). The use of brick elements and the inter pile elements to model pile for the same PR clay system were assessed by Varghese et al [2019] and Boominathan et al [2018], respectively. Although these studies were limited to a single ground motion, a reasonable match with experimental results was observed.…”

Section: Fe Model Of the Foundation-soil Systemmentioning

confidence: 99%

Seismic Response Characteristics of a Piled Raft in Clay

Varghese

Boominathan

Banerjee

2019

J. Earthquake and Tsunami

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This paper presents a study on three-dimensional seismic soil–structure interaction analysis of a piled-raft (PR) foundation in clay by the substructure approach. Two different pile modeling techniques were adopted and compared with centrifuge shaking table test results reported in the literature. The effect of pile spacing on dynamic impedances, kinematic response parameters, axial pile forces and bending moments of PRs is studied. It is found that the presence of a rigid raft on a pile group results in significant variation in vertical and horizontal dynamic stiffness after a dimensionless frequency ([Formula: see text] value of around 0.22. The influence of raft on kinematic response parameters at the top of raft is found to be significantly influenced by pile spacing beyond a dimensionless frequency ([Formula: see text] value of 0.4. The axial forces generated at the pile heads of a PR–structure system during seismic shaking are quantified using a new dimensionless factor, and are found to be significantly influenced by the pile spacing. Pile layout in the PR system is found to play an influential role in seismic response as well as pile bending moment for a structure–PR–soil system studied.

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Section: Fe Model Of the Foundation-soil Systemmentioning

confidence: 99%

Seismic Response Characteristics of a Piled Raft in Clay

Varghese

Boominathan

Banerjee

2019

J. Earthquake and Tsunami

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3D Numerical Analyses for Optimization of Deep-Mixing Columns Combined by Raft Foundations

2021

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Pile induced filtering of seismic ground motion in homogeneous soil

Varghese

Boominathan

Banerjee

2020

IOP Conf. Ser.: Earth Environ. Sci.

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The foundation input motion (FIM) that a structure experiences during an earthquake, is known to be different from the free field ground motion due to soil structure interaction (SSI) effects. Kinematic interaction in a single pile can also introduce a rotational component to the FIM. Conventionally, soil structure interaction is performed by applying the free field ground motion to the structure ignoring the effects of kinematic interaction. Deep foundation elements such as piles are known to suppress certain frequencies of ground motion which in turn induces kinematic bending moments in them. In this study, kinematic soil pile interaction is simulated using 3D numerical models using a coupled finite element-boundary element method. Single pile, group pile and piled raft models in a homogeneous soil profile are analysed for vertically propagating shear waves. Three earthquake time histories with varying frequency content are considered in this study. Transfer functions are then plotted together to analyse the effects of pile induced filtering of ground motion. The ratio of response spectrum at the foundation level and free field ground, for the pile group considered, is found to closely follow the behaviour of a fixed headed single pile. It is found that embedment of the pile cap, as in the case of a piled raft can result in further filtering of ground motion.

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Numerical Analysis of Seismic Response of a Piled Raft Foundation System

Cited by 3 publications

References 4 publications

Seismic Response Characteristics of a Piled Raft in Clay

Seismic Response Characteristics of a Piled Raft in Clay

3D Numerical Analyses for Optimization of Deep-Mixing Columns Combined by Raft Foundations

Pile induced filtering of seismic ground motion in homogeneous soil

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