1. PhD Student, Dept. of Civil Engineering, Univ. degli Studi di Firenze, Via S. Marta 3, 50139 Firenze, Italy.
2. Professor, Dept. of Civil Engineering, Univ. degli Studi di Firenze, Via S. Marta 3, 50139 Firenze, Italy.
3. Researcher, Hydraulics, Dept. of Civil Engineering, Univ. degli Studi di Firenze, Via S. Marta 3, 50139 Firenze, Italy.