1. Ph.D. Candidate, Laboratory of Reinforced Concrete, Dept. of Civil Engineering, Democritus Univ. of Thrace (DUTh), 67100 Xanthi, Greece.
2. Lecturer, Laboratory of Reinforced Concrete, Dept. of Civil Engineering, Democritus Univ. of Thrace (DUTh), Vas. Sofias 12, 67100 Xanthi, Greece (corresponding author).
3. Professor, Laboratory of Reinforced Concrete, Dept. of Civil Engineering, Democritus Univ. of Thrace (DUTh), 67100 Xanthi, Greece.