1. Graduate Research Assistant, Dept. of Civil and Environmental Engineering, Michigan Technological Univ., Houghton, MI 49931.
2. Associate Professor, Purdue School of Engineering and Technology, Indiana Univ.–Purdue Univ., Indianapolis, IN 46202.
3. Professor, Dept. of Civil and Environmental Engineering, Michigan Technological Univ., Houghton, MI 49931 (corresponding author).