1. Postdoctoral Fellow, Dept. of Engineering, Univ. of Ferrara, 1 Via Saragat, I-44122 Ferrara, Italy (corresponding author).
2. Ph.D. Student, Dept. of Engineering, Univ. of Ferrara, 1 Via Saragat, I-44122 Ferrara, Italy.
3. Professor, Dept. of Engineering, Univ. of Ferrara, 1 Via Saragat, I-44122 Ferrara, Italy.
4. Associate Professor, Dept. of Civil and Environmental Engineering and Architecture, Univ. of Cagliari, 2 Via Marengo, I-09123 Cagliari, Italy.