1. Graduate Research Assistant, Dept. of Civil and Materials Engineering, Univ. of Illinois, 842 West Taylor St. M/C 246, Chicago, IL 60607.
2. Civil Engineer, Robinson Engineering Ltd., Frankfort, IL 60432; formerly, Graduate Research Assistant, Dept. of Civil and Materials Engineering, Univ. of Illinois, 842 West Taylor St. M/C 246, Chicago, IL 60607.
3. Associate Professor, Dept. of Civil and Materials Engineering, Univ. of Illinois, 842 West Taylor St. M/C 246, Chicago, IL 60607 (corresponding author).