1. Graduate Student, Dept. of Civil Engineering, Univ. of Illinois at Urbana-Champaign, 205 N. Mathews Ave., Urbana, IL 61801.
2. Associate, Skidmore, Owings & Merrill, LLP, 224 S. Michigan Ave., Chicago, IL 60604.
3. Partner, Skidmore, Owings & Merrill, LLP, 224 S. Michigan Ave., Chicago, IL 60604.
4. Professor, Dept. of Civil Engineering, Univ. of Illinois at Urbana-Champaign, 205 N. Mathews Ave., Urbana, IL 61801 (corresponding author).