1. Researcher, Dept. of Engineering, Univ. of Ferrara, Via Saragat 1-44100, Ferrara, Italy.
2. Associate Professor, Dept. of Civil Engineering, Univ. of Minho, Azurém 4800-058, Guimarães, Portugal (corresponding author).
3. Assistant Professor, Dept. of Engineering, Univ. of Ferrara, Via Saragat 1-44100, Ferrara, Italy.