1. Assistant Professor, Dept. of Civil Engineering, Federal Univ. of Rio Grande do Sul, 99 Osvaldo Aranha Ave., 3rd Floor, Porto Alegre, CEP 90035-190, Rio Grande do Sul, Brazil (corresponding author).
2. Assistant Professor, Dept. of Industrial Engineering, Federal Univ. of Rio Grande do Sul, 99 Osvaldo Aranha Ave., 5th Floor, Porto Alegre, CEP 90035-190, Rio Grande do Sul, Brazil.
3. Engineer, Dept. of Industrial Engineering, Federal Univ. of Rio Grande do Sul, 99 Osvaldo Aranha Ave., 5th Floor, Porto Alegre, CEP 90035-190, Rio Grande do Sul, Brazil.