Assessment of the local variability of the ground motion due to local lateral heterogeneities and to attenuation properties is crucial toward the realistic definition of the asynchronous motion at the base of the bridge piers. We illustrate the work done in the framework of a large international cooperation to assess the importance of non-synchronous seismic excitation of long structures. To accomplish this task a complete synthetic accelerogram dataset was computed by using as input a set of parameters that describes, to the best of our knowledge, the geological structure and seismotectonic setting of the investigated area. The results show that lateral heterogeneities can produce strong spatial variations in the ground motion even at small incremental distances.
