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Keywords: layered media, pile, raft, boundary elements, finite elements.

Summary

The objective of this paper is to present formulations developed by the authors for soil-structure interaction analysis. The soil is modeled with the boundary element method (BEM) as a layered solid infinite for radial directions. Cylindrical piles are modeled with the finite element method (FEM) using one dimensional elements. The raft is also modeled with the FEM, but with two dimensional elements. The analysis is static and all materials are considered homogeneous, isotropic, elastic and with linear behavior.

Kelvin fundamental solutions are used in the BEM and an alternative multi-region technique is employed. Establishing relations between the displacement fundamental solutions of the different domains, the alternative technique here used allows analyzing all the domains as one unique solid, not requiring equilibrium or compatibility equations. Infinite boundary elements (IBEs) are employed for the far field simulation, allowing computational cost reduction without compromising the result accuracy. The IBE formulation is based on a triangular boundary element instead of the quadrilateral IBEs usually found in the literature.

In the one dimensional elements used for the piles, displacements and tractions along the shaft are approximated by polynomial functions. The triangular three-node finite element employed for the raft is obtained by superposing plate and membrane effects, totalling six degrees of freedom per node. For the FEM-BEM coupling, the BEM tractions are considered as nodal reactions between the contact surfaces. The coupling is established using equilibrium and compatibility equations, obtaining a single system of equations that represents the complete pile-raft-soil problem.

The proposed formulation is applied into two examples and it is concluded that it may be considered a practical and attractive alternative in the field of soil-structure interaction simulation.

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Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Proceedings ISSN 1759-3433 CCP: 102 PROCEEDINGS OF THE FOURTEENTH INTERNATIONAL CONFERENCE ON CIVIL, STRUCTURAL AND ENVIRONMENTAL ENGINEERING COMPUTING Edited by: Paper 196 Simulating Piled Rafts in Layered Media using Finite Element - Boundary Element Formulations D.B. Ribeiro¹ and J.B. Paiva² ¹Polytechnic School of the University of São Paulo, Brazil ²Structural Engineering Department São Carlos Engineering School of the University of São Paulo, Brazil doi:10.4203/ccp.102.196 purchase the full-text of this paper Full Bibliographic Reference for this paper D.B. Ribeiro, J.B. Paiva, "Simulating Piled Rafts in Layered Media using Finite Element - Boundary Element Formulations", in , (Editors), "Proceedings of the Fourteenth International Conference on Civil, Structural and Environmental Engineering Computing", Civil-Comp Press, Stirlingshire, UK, Paper 196, 2013. doi:10.4203/ccp.102.196 Keywords: layered media, pile, raft, boundary elements, finite elements. Summary The objective of this paper is to present formulations developed by the authors for soil-structure interaction analysis. The soil is modeled with the boundary element method (BEM) as a layered solid infinite for radial directions. Cylindrical piles are modeled with the finite element method (FEM) using one dimensional elements. The raft is also modeled with the FEM, but with two dimensional elements. The analysis is static and all materials are considered homogeneous, isotropic, elastic and with linear behavior. Kelvin fundamental solutions are used in the BEM and an alternative multi-region technique is employed. Establishing relations between the displacement fundamental solutions of the different domains, the alternative technique here used allows analyzing all the domains as one unique solid, not requiring equilibrium or compatibility equations. Infinite boundary elements (IBEs) are employed for the far field simulation, allowing computational cost reduction without compromising the result accuracy. The IBE formulation is based on a triangular boundary element instead of the quadrilateral IBEs usually found in the literature. In the one dimensional elements used for the piles, displacements and tractions along the shaft are approximated by polynomial functions. The triangular three-node finite element employed for the raft is obtained by superposing plate and membrane effects, totalling six degrees of freedom per node. For the FEM-BEM coupling, the BEM tractions are considered as nodal reactions between the contact surfaces. The coupling is established using equilibrium and compatibility equations, obtaining a single system of equations that represents the complete pile-raft-soil problem. The proposed formulation is applied into two examples and it is concluded that it may be considered a practical and attractive alternative in the field of soil-structure interaction simulation. purchase the full-text of this paper (price £20) go to the previous paper go to the next paper return to the table of contents return to the book description purchase this book (price £65 +P&P)
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