Influence of strong motion processing on numerical simulations of soil-structure interaction

Numerical simulations aimed at the performance based design in geotechnical earthquake engineering require the selection of suitable input strong motion records. Since many earthquake of the past have been recorded by analog instruments, the corresponding records are often affected by instrumental errors and drifts, affecting an important part of the frequency spectrum. Modern strong motion databases provide both the original uncorrected records (raw data) and the corrected records. Although correction procedures have been significantly harmonized, the expert judgment of the operator still plays an important role in the correction process. As a result, different corrected versions of the same record may be distributed in different strong motion databases. In the present paper the influence of correction procedures in a typical engineering application is studied by performing numerical simulations on the same model with different corrected versions of the same strong motion record. For this purpose, the seismic behavior of a diaphragm wall is simulated using a finite difference scheme. The results show large differences especially in terms of displacements of the wall, which is a parameter of particular relevance when dealing with performance based design.