SSI SoilStructureInteraction
What is SoilStructureInteraction?
In case of vibration of the ground, i.e. during Earthquakes, earthworks or machine vibrations, Waves spread throughout the subsoil, interact with buildings and be reected and broken. This mutual inuence of soil and structure is called Soil Structural Interaction (SSI).
Where is the SSI needed?
 Earthquake proofs of dams
 Proofs of Nuclear Power Plant buildings, their components and pipe systems for earthquake
 Propagation calculation of vibrations i.e. induced by impact piledriving
Our tool  ACS Sassi
In the eld of soilbuilding interaction ACS Sassi is currently the leading software package from Ghiocel Predictive Technologies Inc.
1 Generation of spektra compatible TimeHistories
Given are earthquake loads for a location in the form of freeeld excitations. For the SSI calculation Time Histories are needed. These can be either generated articially or derived from real earthquake events.
2 SSIcomputational Model
 Model of building with the main internals and possibly sourrounding soil (HOUSE)
 SoilModel of the upper Layers and of the infinite halfspace (LAYER)
HouseModel
Modeling of the building and possibly the near field soil. The level of details in the FE model for the SSI calculation determines the computing time. Subsequent transfer of the calculation model and the boundary conditions from the SSI in ANSYS with the possibility of model renement and stress evaluation.
SoilLayer Model
Soil parameters of each Soil layer down to the halfspace:
Iteration of dyn. soil properties:

3 SSICalculation
SITE 

POINT 

HOUSE 

ANALYS 

4 Postprocessing
 Output of accelerations, displacements and stresses
 calculation and processing of the InStructureResponseSpectra
Displacement 
Stress 
Broadening of spectra
 RSSSuperposition of the responses in each spatial direction due to the excitation in each single direction
 Averaging of spectra for the excitation of various time histories
 Capping of peaks
 Broadening of Spectra
 Enveloping the calculation results from different Soil models