1. Assistant Professor, Dept. of Civil Engineering, Univ. of Coimbra, R. Luís Reis Santos, 3030-788 Coimbra, Portugal (corresponding author).
2. Assistant Professor, Dept. of Civil Engineering, Univ. of Coimbra, R. Luís Reis Santos, 3030-788 Coimbra, Portugal.
3. Civil Engineer, R. Santo Velho, n. 71, 3240-307 Avelar, Portugal.