SUMMARY
This paper is devoted to the analysis of elastodynamic problems in 3D-layered systems which are unbounded in the horizontal direction. For this purpose, a finite element model of the near field is coupled to a scaled boundary finite element model (SBFEM) of the far field. The SBFEM is originally based on describing the geometry of a half-space or full-space domain by scaling the geometry of the near field / far field interface using a radial coordinate. A modified form of the SBFEM for waves in a 2D layer is also available. None of these existing formulations can be used to describe a 3D-layered medium.

In this paper, a modified SBFEM for the analysis of 3D-layered continua is derived. Based on the use of a scaling line instead of a scaling centre, a suitable scaled boundary transformation is proposed. The derivation of the corresponding scaled boundary finite element (SBFE) equations in displacement and stiffness is presented in detail. The latter is a nonlinear differential equation with respect to the radial coordinate, which has to be solved numerically for each excitation frequency considered in the analysis.

Various numerical examples demonstrate the accuracy of the new method and its correct implementation. These include rigid circular and square foundations embedded in or resting on the surface of layered homogeneous or inhomogeneous 3D soil deposits over rigid bedrock. Hysteretic damping is assumed in some cases. The dynamic stiffness coefficients calculated using the proposed method are compared with analytical solutions or existing highly accurate numerical results. Copyright © 2011 John Wiley & Sons, Ltd.

A modified scaled boundary finite element method for three‐dimensional dynamic soil‐structure interaction in layered soil

This study addresses the responses of idealized building clusters during earthquakes, their effects on ground motion, and the ways individual buildings interact with the soil and with each other. W...

Coupled Soil-Structure Interaction Effects of Building Clusters during Earthquakes

An efficient approach for dynamic impedance of surface footing on layered half-space

Kinematic bending moments in pile foundations

Equivalent linear and nonlinear site response analysis for design and risk assessment of safety-related nuclear structures

Presented here is a numerical investigation of the influence of non-uniform soil conditions on a prototype concrete bridge with three bents (four span) where soil beneath bridge bents are varied between stiff sands and soft clay. A series of high-fidelity models of the soil-foundation-structure system were developed and described in some details. Development of a series of high-fidelity models was required to properly simulate seismic wave propagation (frequency Lip to 10Hz) through highly nonlinear, elastic plastic soil, piles and bridge structure. Eight specific cases representing combinations of different soil conditions beneath each Of the bents are simulated. It is shown that variability of soil beneath bridge bents has significant influence on bridge system (soil-foundation-structure) seismic behavior. Results also indicate that free field motions differ quite a bit from what is observed (simulated) under at the base of the bridge columns indicating that use of free field motions as input for only structural models might not be appropriate. In addition to that, it is also shown that usually assumed beneficial effect Of Stiff soils underneath a Structure (bridge) cannot be,generalized and that such stiff soils do not necessarily help seismic performance of structures. Moreover, it is shown that dynamic characteristics of all three components of a triad made Lip of earthquake, soil and structure play crucial role in determining the seismic performance of the infrastructure (bridge) system. Copyright (C) 2009 John Wiley & Sons, Ltd.

Time domain simulation of soil-foundation-structure interaction in non-uniform soils

Note: [397] Reference LCH-ARTICLE-2003-013View record in Web of Science Record created on 2007-04-24, modified on 2016-08-08

Dynamic stiffness of foundation embedded in layered halfspace based on wave propagation in cones

Two-phase free-surface fluid dynamics on moving domains

Current design practice for structures subject to earthquake loading regards dy- namic Soil-foundation-Structure Interaction (SFSI) to be beneficial to the behavior of structures. Including the flexibility of the foundation and soil reduces the overall stiffness of a SFS system and can therefore reduce peak loads caused by a given ground motion. This might be true in (some) many cases. However, there is the possibility of SFS system going into resonance with the exciting earthquake motions as a result of a shift of the natural frequencies of the SFS-system. This can lead to much larger inertial forces acting on a structure. In that case, the SFSI is not beneficial, but rather detrimental to the seismic response of the structures (and of the SFS system). In this paper we present methodology and an analysis of beneficial and detrimental effects SFSI can have on seismic response. It will be shown that an interaction between SFS system and the seismic motions plays crucial role in determining if SFSI will be beneficial or detrimental. In other words, SFSI can be both beneficial and detrimental for a particular SFS system, depending on the characteristics of the seismic motions exciting the system.

Matthias Preisig

Papers

Time domain simulation of soil-foundation-structure interaction in non-uniform soils

Dynamic stiffness of foundation embedded in layered halfspace based on wave propagation in cones

Two-phase free-surface fluid dynamics on moving domains

Benefits and Detriments of Soil Foundation Structure Interaction

Free-surface fluid dynamics on moving domains