[1] FURNAS Hydropower Co, Civil Engn Ctr FURNAS Cent Eletricas SA, Goiania, Go, Brazil
[2] Univ Fed Rio Grande do Sul, Porto Alegre, RS, Brazil
[3] Univ Brasilia, BR-70910900 Brasilia, DF, Brazil
[4] Univ Fed Rio de Janeiro, Rio De Janeiro, Brazil
[5] Univ Sao Paulo, Sao Paulo, Brazil
[6] Univ Fed Rio de Janeiro, COPPE, Civil Engn Program, BR-21941 Rio De Janeiro, Brazil