1. Research Officer, National Laboratory for Civil Engineering, Av. do Brasil, 101, 1700-066 Lisboa, Portugal.
2. Assistant Professor, Lisbon Technical Univ., Dept. of Civil Engineering, Av. Rovisco Pais 1049-001 Lisboa, Portugal.
3. Principal Research Officer, National Laboratory for Civil Engineering, Av. do Brasil, 101, 1700-066 Lisboa, Portugal.