MTR/SASSI software is a substructuring program that uses the complex frequency response method and finite element technique to solve a wide range of dynamic soil-structure interaction problems.

The program has been developed specifically for practical applications and has the following characteristics:

• Site response analysis, subgrade impedance analysis, and formation of the basic stiffness and mass matrices for the structure can be performed separately. The results are stored on disc files.
• If the seismic wave field, external loads, soil properties, or the properties of superstructure are changed, only part of the computation needs to be repeated.
• The final response transfer functions are stored on a disk file from which specific information can be extracted without re-computing the entire solution.
• Both deterministic and probabilistic results can be obtained from the above file.