1. Professor, Dept. of Civil and Environmental Engineering, Michigan Technological Univ., 1400 Townsend Dr., Houghton, MI 49931 (corresponding author).
2. Graduate Research Assistant, Dept. of Civil and Environmental Engineering, Michigan Technological Univ., 1400 Townsend Dr., Houghton, MI 49931.
3. Lecturer, School of Engineering, Monash Univ., Sunway Campus, 47500 Subang Jaya, Selangor, Malaysia.
4. Associate Professor, Dept. of Civil Engineering and Engineering Mechanics, Columbia Univ., 500 West 120th St., New York, NY 10027.