1. Research Fellow, Dept. of Civil, Architectural and Environmental Engineering, Univ. of Naples Federico II, via Claudio 21, 80125 Napoli, Italy (corresponding author).
2. Freelancer, RDR Company, via Nazionale 715/S, 80059 Torre del Greco, Italy.
3. Full Professor, Dept. of Civil, Architectural and Environmental Engineering, Univ. of Naples Federico II, via Claudio 21, 80125 Napoli, Italy.