1. Ph.D. Candidate, Dept. of Civil Engineering, Democritus Univ. of Thrace, Vassillissis Sofias 12, GR-67100 Xanthi, Greece (corresponding author).
2. Professor, Dept. of Civil Engineering, Democritus Univ. of Thrace, Vassillissis Sofias 12, GR-67100 Xanthi, Greece.
3. Professor, Faculty of Medicine, Aristotle Univ. of Thessaloniki, GR-54124 Thessaloniki, Greece.