1. Ph.D Candidate, Dept. of Civil and Transport Engineering, Norwegian Univ. of Science and Technology (NTNU), Høgskoleringen 7a, Trondheim NO-7491, Norway (corresponding author).
2. Associate Professor, Dept. of Civil and Transport Engineering, Norwegian Univ. of Science and Technology (NTNU), Høgskoleringen 7a, Trondheim NO-7491, Norway.
3. Retired, Dept. of Civil and Transport Engineering, Norwegian Univ. of Science and Technology (NTNU), Høgskoleringen 7a, Trondheim NO-7491, Norway.