1. Civil Engineer, FLUOR, Reyes Lavalle 3340, Las Condes, 7550121 Santiago, Chile.
2. Associate Professor, Dept. of Civil Engineering, Univ. of Chile, Piso 4, 8370449 Santiago, Chile (corresponding author).
3. CEO and Chief Engineer, ALV Engineers & Associates, Avenida Vitacura 2909 of 801 Las Condes, 7550024 Santiago, Chile.