1. Department of Civil and Environmental Engineering, Ruhr Universität Bochum, Germany.
2. Institute of Structural Engineering, Bauhaus Universität Weimar, Germany; also Ruhr Universität Bochum, Germany.
3. Institute of Geotechnics, Technische Universität Darmstadt, Germany; also Ruhr-Universität Bochum, Germany.
4. Institute of Geotechnics, Technische Universität Darmstadt, Germany.
5. Ruhr-Universität Bochum, Germany.