1. Lecturer, Dept. of Civil Engineering, Aristotle Univ., Thessaloniki, GR, e-mail: anas@civil.auth.gr
2. Post-Doctoral Fellow, Dept. of Civil and Architectural Engineering, City University of Hong Kong, Hong Kong, formerly Aristotle University of Thessaloniki, GR, e-mail: ksenetak@civil.auth.gr
3. Professor, Dept. of Civil Engineering, Aristotle Univ., Thessaloniki, GR, e-mail: kpitilak@civil.auth.gr
4. Civil Engineer, Dept. of Civil Engineering, Aristotle Univ., Thessaloniki, GR.