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