1. Dept. of Civil, Environmental and Geomatic Engineering, Institute of Structural Engineering, ETH Zurich, Stefano-Franscini-Platz 5, 8093 Zurich, Switzerland.
2. Dept. of Civil, Environmental and Geomatic Engineering, Institute of Structural Engineering, ETH Zurich, Stefano-Franscini-Platz 5, 8093 Zurich, Switzerland (corresponding author).