1. Dept. of Civil, Mining and Environmental Engineering, Luleå Univ. of Technology, 971 87 Luleå, Sweden (corresponding author).
2. Associate Professor, Dept. of Architecture and Planning, Univ. of Sassari, Palazzo del Pou Salit, Piazza Duomo 6, 07041 Alghero, Italy.
3. Dept. of Civil, Mining and Environmental Engineering, Luleå Univ. of Technology, 971 87 Luleå, Sweden.