The Application Of Boundary Element Techniques For Some Soil Structure Interaction Problems

The Application of Boundary-element Techniques for Some Soil-structure Interaction Problems

Boundary-element technique research performed to solve soil-structure interaction problems is the basis for this report. Specifically, it was designed to answer questionable situations for long hydraulic U-Lock structures erected on elastic soil. A review of earlier research that employed the Kelvin-type element directed the decision in favor of Flamant-type boundary element. Both constant and linear elements were developed and many sample problems were dealt with to illustrate the capabilities of these elements in the problem situations of soil-structure relationships. The Flamant-type boundary element proved to be convenient, gave better results for displacement problems using the constant element, offered satisfactory behavior description of soil-structure response, required considerably fewer elements than the conventional model, provided more accuracy in stress analysis of structure, and was confirmed as very beneficial for use in input data preparation. Research was also conducted on soil-structure interaction problems with the structure modeled by the finite-element method and the soil modeled by the boundary-element method. A model problem suggested by the AEWES was selected for study and solving. The emphasis was to develop a convenient and economical technique to couple the boundary- and finite-element methods of analysis. A computer code for coupling the two methods has been developed in FORTRAN. Keywords: Soil mechanics; Structural engineering; Mathematical analysis.

Boundary Element Methods for Soil-Structure Interaction

W S HALL School of Computing and Mathematics, University of Teesside, Middlesbrough, TS1 3BA UK G OLIVETO Division of Structural Engineering, Department of Civil and Environmental Engineering, University of Catania, Viale A. Doria 6, 95125 Catania, Italy Soil-Structure Interaction is a challenging multidisciplinary subject which covers several areas of Civil Engineering. Virtually every construction is connected to the ground and the interaction between the artefact and the foundation medium may affect considerably both the superstructure and the foundation soil. The Soil-Structure Interaction problem has become an important feature of Structural Engineering with the advent of massive constructions on soft soils such as nuclear power plants, concrete and earth dams. Buildings, bridges, tunnels and underground structures may also require particular attention to be given to the problems of Soil-Structure Interaction. Dynamic Soil-Structure Interaction is prominent in Earthquake Engineering problems. The complexity of the problem, due also to its multidisciplinary nature and to the fact of having to consider bounded and unbounded media of different mechanical characteristics, requires a numerical treatment for any application of engineering significance. The Boundary Element Method appears to be well suited to solve problems of Soil- Structure Interaction through its ability to discretize only the boundaries of complex and often unbounded geometries. Non-linear problems which often arise in Soil-Structure Interaction may also be treated advantageously by a judicious mix of Boundary and Finite Element discretizations.

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