1. Civ. Engr., Asst. Prof., Dept. of Transp. Plng. and Engrg., National Technical Univ. of Athens, 5, Iroon Polytechniou St. GR-157 73 Zografou, Athens, Greece. E-mail: dtsamb@central.ntua.gr
2. Civ. Engr. Res., Dept. of Transp. Plng. and Engrg., National Technical Univ. of Athens, 5, Iroon Polytechniou St. GR-157 73 Zografou, Athens, Greece.
3. Engrg. Geol., Res., Dept. of Min. and Metallurgy, National Technical University of Athens, 5, Iroon Polytechniou St. GR-157 73 Zografou, Athens, Greece.