1. M.Sc. Civil Engineer, Dept. of Civil and Environmental Engineering, Pontifical Catholic Univ. of Rio de Janeiro, Rio de Janeiro 22451-900, Brazil.
2. Doctoral Candidate, Dept. of Civil and Environmental Engineering, Pontifical Catholic Univ. of Rio de Janeiro, Rio de Janeiro 22451-900, Brazil (corresponding author).
3. Full Professor, Dept. of Civil and Environmental Engineering, Univ. of Brasília, Brasília 70.910-900, Brazil.