1. University of Thessaly , Department of Civil Engineering , Pedion Areos, GR-38334 Volos , Greece , Ph.: +302421074133, Fax: +302421074131
2. University of Thessaly , Department of Civil Engineering , Pedion Areos, GR-38334 Volos , Greece , Ph.: +302421074158, Fax: +302421074131
3. University of Thessaly , Department of Civil Engineering , Pedion Areos, GR-38334 Volos , Greece , Ph.: +302421074164, Fax: +302421074131
4. Transport and Telecommunication Institute , Lomonosova Street 1, LV-1019 Riga , Latvia , Ph.: +37167100544, Fax: +37167100660