1. Building Engineer, Lecturer, Polytechnic School, Univ. of Extremadura, Ave. de las Letras s/n, 10004 Cáceres, Spain.
2. Full Professor, Dept. of Civil Engineering, Architecture, and Georresources, Instituto Superior Técnico, Univ. of Lisbon, Ave. Rovisco Pais, 1049-001 Lisbon, Portugal (corresponding author).