1. Department of Civil and Transport Engineering, Norwegian University of Science and Technology, Høgskoleringen 7A, NO-7491 Trondheim, Norway.
2. Department of Industrial and Systems Engineering and Department of Civil and Environmental Engineering, School of Engineering, University of Washington, Box 352650, Seattle, WA 98195-2650.
3. Department of Civil and Environmental Engineering, School of Engineering, University of Washington, Box 352700, Seattle, WA 98195-2700.