1. Ph.D. Student, Dept. of Civil and Environmental Engineering, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milan, Italy (corresponding author).
2. Associate Professor, Dept. of Civil, Environmental and Geomatic Engineering, Institute of Structural Engineering, Eidgenössische Technische Hochschule Zürich, Stefano-Franscini-Platz 5, 8093 Zürich, Switzerland.
3. Associate Professor, Dept. of Civil and Environmental Engineering, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milan, Italy.