1. Professor, Dept. of Civil Engineering, K.U.Leuven, Kasteelpark Arenberg 40, B-3001 Leuven, Belgium (corresponding author).
2. Doctoral Student, Dept. of Civil Engineering, K.U.Leuven, Kasteelpark Arenberg 40, B-3001 Leuven, Belgium.
3. Postdoctoral Researcher, FWO Flanders, Dept. of Civil Engineering, K.U.Leuven, Kasteelpark Arenberg 40, B-3001 Leuven, Belgium.
4. Postdoctoral Researcher, Dept. of Civil Engineering, K.U.Leuven, Kasteelpark Arenberg 40, B-3001 Leuven, Belgium.
5. Post-Doctoral Researcher, Dept. of Civil Engineering, K.U.Leuven, Kasteelpark Arenberg 40, B-3001 Leuven, Belgium; presently, Tractebel Engineering International, B-1200 Brussels, Belgium.