1. Assistant Professor, Dept. of Construction Engineering, Civil Engineering School, Technical Univ. of Catalonia, Jordi Girona 1-3, C-1 201, 08034 Barcelona, Spain (corresponding author).
2. Engineer, Tec-Cuatro, S.A., Amigó 15, 1ª Planta, 08021 Barcelona, Spain.
3. Professor, Dept. of Construction Engineering, Civil Engineering School, Technical Univ. of Catalonia, Jordi Girona 1-3, C-1 201, 08034 Barcelona, Spain.