1. Ph.D. Student, Dept. of Civil Engineering, Federal Univ. of Sao Carlos, Rod. Washington Luís, km 235, SP-310, 13565-905, São Carlos, SP, Brazil (corresponding author).
2. Associate Professor, Dept. of Civil Engineering, Federal Univ. of Sao Carlos, Rod. Washington Luís, km 235, SP-310, 13565-905, São Carlos, SP, Brazil.
3. Professor, Dept. of Civil and Environmental Engineering, Brigham Young Univ., 368 Clyde Bldg., Provo, UT 84602.
4. Full Professor, Dept. of Civil Engineering, Sao Paulo State Univ., Alameda Bahia, 550, 13565-905, Ilha Solteira, SP, Brazil.