r4.05.04 Soil-structure interaction with spatial variability (operator DYNA_ISS_VARI)

Summary:

This document is a theoretical guide describing the methods developed in operator DYNA_ISS_VARI. This operator makes it possible to deal with soil-structure interaction problems (ISS) in seismic analysis where it is desired to take into account the spatial variability of the incident seismic field. In the context of a standard seismic study with soil-structure interaction using Code_Aster/MISS3D chaining, it is assumed that the seismic excitation does not vary spatially. However, spatial variability can have significant effects on the response of structures subjected to an earthquake. In particular, we observe a reduction in the translation response, which can make it possible to create margins in ISS calculations.

DYNA_ISS_VARI makes it possible to calculate the response of a structure subjected to a variable seismic movement in space based on a coherence function, the impedance matrix and the seismic force. These can be calculated by the software MISS3D. More precisely, the modal response spectral vectors (resulting from a spectral decomposition of the coherence matrix) are constructed by means of a harmonic calculation into generalized components. At the output, we obtain the spectral density of the modal response (for a unit excitation) or the temporal response (in acceleration).

• 1. Introduction
• 2. Order description DYNA_ISS_VARI
  • 2.1. Seismic analysis with ISS in the frequency domain
  • 2.2. Taking account of spatial variability
  • 2.3. Results calculated by DYNA_ISS_VARI
• 3. Other software: SASSI and CLASSI
• 4. Bibliography
• 5. Description of document versions