Why use SASSI?

SASSI is a substructuring program that uses the complex frequency response method and finite element technique to solve soil-structure interaction (SSI) problems. This offers several advantages over other finite element programs in which the total SSI system is solved in one step.

1. 1. Because soil shear modules and damping properties are independent of shear strain rate in earthquake engineering applications, they are best characterized in the frequency domain using complex-valued stiffness parameters.
   2. Because nonlinear soil shear modules and damping properties depend mainly on the maximum effective shear strain, nonlinearity in the soil can be accounted for by iterating on soil properties using the equivalent linear procedure. Although this procedure introduces some approximations, its application in real engineering problems has been shown to be adequate in light of great uncertainty regarding dynamic soil properties.
   3. In total SSI analysis, a large finite element mesh is often required to model unbounded soil media. SASSI uses the point load solution in a layered soil system to derive dynamic impedance properties at the soil/structure interface, which account for wave radiation in unbounded soil media. This significantly reduces computational effort.
   4. Because SASSI uses the frequency domain method, analysis for different input motions is basically a post-processing effort. This significantly reduces the numerical analysis effort compared to the time domain method.

What are the advantages of MTR/SASSI?

• Flexible node and element numbering for seamless interfacing with other structural software.
• Extensive new capabilities for modeling complex SSI systems.
• Advanced solver and parallel processing for fast and efficient analysis of large SSI models.
• Improved software performance, scalability, and reliability.
• Extensive verification and validation for reliable and accurate results.
• Available technical support for smooth and uninterrupted project execution.
• Optional integrated Graphical User Interface (GUI).
• Support for the latest multicore and manycore based systems.
• Versions available on both Windows and Linux platforms.
• Versions available for Standard Parallel Compuing (SPC), High Speed Parallel Computing (HSPC) and High Performance Super Computing (HPSC) and High Performance Cloud Computing (HPCC).