1. Assistant Professor, Dept. of Civil and Environmental Engineering, Univ. of California, Davis, 2001 Engineering III, One Shields Ave., Davis, CA 95616 (corresponding author).
2. Research Assistant, Dept. of Civil and Environmental Engineering, Univ. of California, Davis, 2001 Engineering III, One Shields Ave., Davis, CA 95616.
3. Associate Professor, Departamento de Ingeniería Civil, Universidad de Chile, Av. Blanco Encalada 2002, 3er. piso, Santiago de Chile, Chile.