1. Associate Professor, Dept. of Civil Engineering, Univ. of Thessaly, Pedion Areos, 383 34 Volos, Greece (corresponding author).
2. MSc, Senior Engineer, GeoStatiki S. A. Consulting Engineers, 3 Sapfous Str., 54627 Thessaloniki, Greece.
3. Ing. Dr., C.E.O., Egnatia Odos S.A., P.O. Box 60030, 57001 Thessaloniki, Greece.