1. Research Assistant, Lyles School of Civil Engineering, Purdue Univ., West Lafayette, IN 47907; Associate Professor, School of Civil Engineering, Univ. del Valle, Cali, Colombia (corresponding author).
2. Professor, School of Civil and Mechanical Engineering, Purdue Univ., West Lafayette, IN 47907.
3. Professor, Dept. of Health and Kinesiology, Purdue Univ., West Lafayette, IN 47907.