1. Professor, Laboratory of Reinforced Concrete, Dept. of Civil Engineering, Democritus Univ. of Thrace (DUTh), 67100 Xanthi, Greece. E-mail: karabin@civil.duth.gr
2. Dr. Civil Engineer, Laboratory of Reinforced Concrete, Dept. of Civil Engineering, Democritus Univ. of Thrace (DUTh), Vas. Sofias 12, 67100 Xanthi, Greece. E-mail: trousak@civil.duth.gr
3. Civil Engineer, Ph.D. Candidate, Laboratory of Reinforced Concrete, Dept. of Civil Engineering, Democritus Univ. of Thrace (DUTh), 67100 Xanthi, Greece. E-mail: gmanolit@civil.duth.gr