1. Assistant Professor, Dept. of Civil Engineering, IST/ICIST, Technical Univ. of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon, Portugal.
2. Associate Professor, Dept. of Civil Engineering, IST/ICIST, Technical Univ. of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon, Portugal (corresponding author).