1. Department of Civil and Environmental Engineering, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
2. Department of Mechanical Engineering, Politecnico di Milano, Via Giuseppe La Masa 1, 20156 Milano, Italy
3. Department of Civil, Environmental, and Geomatic Engineering, ETH, Stefano-Franscini-Platz, 5 8093 Zürich, Switzerland
4. Department of Mathematics, Imperial College London, London SW7 2AZ, United Kingdom
5. Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, United Kingdom
6. UMI 2004 Abraham de Moivre-CNRS, Imperial College London, London SW7 2AZ, United Kingdom