1. Assistant Professor of Structural Engineering, Dept. of Civil Engineering, Univ. of Salerno, via Ponte don Melillo, 84084 Fisciano (SA), Italy (corresponding author).
2. Full Professor of Structural Engineering, Dept. of Civil Engineering, Univ. of Salerno, via Ponte don Melillo, 84084 Fisciano (SA), Italy.
3. Ph.D. Scholar, Dept. of Civil Engineering, Univ. of Salerno, via Ponte don Melillo, 84084 Fisciano (SA), Italy.